Home

Matisse User's Guide - Spectra

1. 0 07 1 1 1 1 1 1 1 1 179 3 18000 18200 18400 18600 18800 19000 19200 19400 19600 19800 20000 Thin Etalon motor position Options Ol The blue curve looks similar to a sequence of parabolas with minima Changing the thin etalon s position within such a parabola will not change the Matisse wavelength If you change the motor position from one parabola to the next one the Matisse frequency will change normally by one Free Spectral Range of the Thick Piezo Etalon see the Single Frequency Tunable Laser Physics see page 30 chapter for more details Once the acquisition 1s finished drag the line towards the minimum of the parabola where the original thin etalon motor position was located Set the line on the left hand side of the minimum as shown in the next Figure Click on Set and the thin etalon will be moved to the stepper motor position indicated by the red cursor You have to hit Set even if the default position of the red cursor is the position you want to keep because otherwise the etalon will stay in the utmost right position on the displayed motor position scale The software operates with the gradient of the reflected power therefore the cursor needs to be set well outside the minimum of the curve On the other hand setting the etalon too far away from the minimum of the blue curve will decrease the emitted laser power because the minimum of the curve indicating the reflection from the etalon coincides with the maximum of t
2. Scan Lower Limit Jj 0 125599 Sampling Points Jj 128 Amplitude Sampling Mode J Average l Modulation On 60 Time cov active Autoscale Y Axis PDH Multiplexer Input Jj Mixer Output Basic Advanced DSP Offset Jj 103 Phaseshift tJ 150 The graph shows the various signals Photo Diode signal Phase Mixer output Slow Side EOM signal Transmission Diode signal that play a role for the PDH stabilization scheme by choosing the PDH Multiplexer Input Modulation On indicates sets the status of the 20 MHz sideband generation and EOM active shows sets the control status of the intra cavity EOM PDH Multiplexer Input shows which signal is currently as output from the multiplexer Modulation On indicates sets the status of the 20 MHz sideband generation and EOM active shows sets the control status of the intra cavity EOM Basic Parameters DSP Offset will change the baseline of the Phase Mixer signal Choose a value so that the baseline is around zero The Phaseshift determines the phase between the 20 MHz sine modulation and the detector signal This phase will determine the shape of the PDH error signal Choose a value that results in an symmetric error signal with a steep slope in its center Advanced Parameters The Attenuator value determines how strong the intra cavity EOM will react on deviations from the zero crossing of the PDH error signal Matisse Commander 103 With
3. Even with the by pass open some dye will enter the tube leading to the dye nozzle Carefully observe the dye flowing towards the nozzle Wait until the dye reaches the nozzle Once the entire tube from the circulator to the nozzle is filled with dye wait for another 5 minutes before proceeding Basic Matisse Operation 50 12 DO NOT open the spray guard to watch the dye arriving in the nozzle only check its appearance in the different tubing sections 13 Slowly close the needle valve on the circulator in order to increase the dye pressure In a first step only increase the pressure by 1 4 bar Wait for 5 minutes Increase the pressure by another 1 4 bar wait another 5 minutes Continue to increase the pressure in similar steps until the pressure reaches 2 5 bar Wait for 5 minutes While doing these steps of increasing pressure check the dye flow in the drain back from the dye catching tube towards the pump Note that the dye drain is only driven by gravity If ever you realize that the tube s position does not allow proper dye flow e g because tube s slope is not sufficient then immediately switch off the dye pump and change the position of the drain If too much dye accumulates in the tube and does not flow back to the pump properly then in the worst case the dye may flow backwards out of the dye catching tube in your laser 14 If the dye flows properly with a pressure of 2 5 bar then carefully increase the pressure in one sin
4. Frequency Hz 3000 0 Amplitude 0 76094 Waveform Close The advanced tab is divided into three sections each section controls a different aspect of the piezo etalon Oversampling and Sample Rate control the modulation frequency Average and Proportional Gain control the action of the control loop Phase Shift and Amplitude the action of the feed forward to the tweeter Oversampling This parameter determines how many samples are used to synthesize the modulation waveform The minimum value is 8 the maximum value is 64 samples per period Sample Rate This parameter determines the rate at which each of the sample points is transferred to the piezo etalon The combination of Oversampling and Sample Rate determines the frequency of the modulation f mod Sample Rate Oversampling Valid Sample Rates are 8 kHz 32 kHz 48 kHz 96 kHz Hence the limits for the modulation frequency are 125 Hz and 12 kHz Frequency Output Displays the calculated modulation frequency for the selected combination of Sample Rate and Oversampling Average This parameter determines how many cycles of the modulation are averaged before the controller action is calculated An increase in the number of averaged cycles lead to a betters signal to noise ratio of the control signal but makes the control loop less responsive Matisse Commander 86 Proportional Gain The Proportional Gain determines the magnitude of the controller action
5. Safety P recautions 12 Never place reflecting surfaces into the laser beam before having verified where the reflected beam will go Even absorbers and beam dumps may reflect a considerable amount of laser power which can be sufficient to cause severe injuries or damages at the power levels common in the operation of your laser The introduction of lenses into the laser beam requires special caution because its curved surfaces generate additional laser foci in the reflected beam which are able to destroy optical elements Use the pump laser at the lowest possible power level Especially for alignment purposes you should use the pump laser at a power level which is just slightly above the threshold power level of the Matisse laser Never expose your skin to the laser radiation All laser beams have to be terminated with a beam stop All experiments to which the laser is applied have to be designed in such a way that the laser beams are confined to the experimental set up All laser beams for which the set up itself does not provide a suitable beam stop have to be terminated with a beam dump Operate the laser only inside distinctly marked areas The laser should only be operated inside a room distinctly marked with respective warning signs and warning lamps The access to this room has to be restricted to personnel properly trained Do not install the laser in a height that the output is at eye level Maintain a high ambient light level
6. 0 6151 708 217 Germany Sirah Laser und Plasmatechnik GmbH Ludwig Erhard Str 10 D 41564 Kaarst Telephone 49 0 2131 66 06 51 Fax 49 0 2131 66 80 95 E mail info sirah com Internet www sirah com Customer Service 135 Japan East Spectra Physics KK East Regional Office Daiwa Nakameguro Building 4 6 1 Nakameguro Meguro ku Tokyo 153 Telephone 81 3 3794 5511 Fax 81 3 3794 5510 gt Japan West Spectra Physics KK West Regional Office Cycnas Building 2 19 Uchihirano Cho Chuo ku Osaka Telephone 81 3 6941 7331 Fax 81 3 6941 2700 gt United States and Export Countries Spectra Physics Lasers 1330 Terra Bella Avenue Mountain View CA 94043 Telephone 1 800 456 2552 Service 1 800 775 5273 Sales Fax 1 650 964 3584 E mail service splasers com sales splasers com Internet WWW spectra physics com Problems and Solutions Customer Service 136 This form should encourage you to tell us about difficulties you have experienced when using your Sirah instruments or this manual problems that did not require a formal call or letter but which you should feel free to communicate We are always interested in improving our products and manuals and we appreciate your suggestions Thank you From Name University Company Institute Department Address gt Instrument Type Serial Numb
7. Slow Piezo Control Setup Figure 55 SPZ Control Setup dialog only available for Matisse TS DS and TX DX Slow Piezo Control Setup Setpoint io Free Proportional Gain 10 Locked Proportional Gain ilo Locked Integral Gain io Slow Piezo Control In this dialog you can determine the behavior of the Slow Piezo control loop by setting the loop s parameters The Setpoint defines the point in the nominal voltage range of the Fast Piezo from 0 to 0 7 to which the Fast Piezo is kept with the help of the Slow Piezo It should be set to 0 5 so that the Fast Piezo has the full dynamical range available to react on pertubations to keep the laser locked to the reference resonator The Lock Proportional Gain and the Lock Integral Gain are the control loop parameters used when the laser is in the lock The Free Proportional Gain determines the scan speed of the slow piezo for the scan that is executed to find or regain a resonance of the reference resonator to lock the laser to if the lock was lost Slow Piezo Control will switch the control loop on or off Changing the controls values has an immediate effect on the control loop RefCell Waveform Figure 56 Waveform display RefCell Matisse Commander 93 only available for Matisse TS DS RefCell Waveform Scan Upper Limit ot Scan Lower Limit 0 085 Oversampling 128 3 2 k 3 l a z X Sampling Mode Jj Maxim
8. Material under warranty will be repaired or replaced FOB our shipping point by Sirah Sirah will provide an on site field service representative in a reasonable amount of time provided the customer issues a valid purchase order to Sirah covering all transportation and subsistence costs For warranty field repairs the customer will not be charged for the cost of labour and material Material not under warranty may be returned to Sirah for repair or replacement Sirah will advise you of the cost and delivery time to repair the equipment before beginning work on it Customer Service 133 Return of the Instrument for Repair Before any return of instrument please contact your local Sirah service or sales centre for shipping instructions or an on site service appointment You are responsible for the one way shipment of the defective instrument to the Sirah service centre Always use the original packing boxes for shipment If shipping boxes have been destroyed or lost we recommend you to order new ones We will return instruments only in Sirah transport boxes Customer Service 134 Service Centres Central Europe Spectra Physics Europe Guerickeweg 7 D 64291 Darmstadt Telephone 49 0 6151 708 0 25 Dutch spoken 257 French spoken Fax 49 0 6151 708 217 gt Europe and Middle Eastern Countries Spectra Physics Guerickeweg 7 D 64291 Darmstadt Telephone 49 0 6151 708 219 Fax 49
9. Pump laser power 5 20W Ambient conditions constant temperature in the 20 25 C range non condensing humidity conditions Cooling required for crystal lt 10 W Laboratory vibrational isolated optical table dust free air flow box Electrical 100 250 V max 2 5 Amps Computer control Windows 2000 or Windows XP system USB port Matisse Laser Description 26 Matisse DR Specifications This section summarizes the specifications of the Matisse DR laser Please note that specifications are subject to change without notice Tuning range Pump laser Optics set Output range Millennia Pro 10s MOS 4 550 660 nm Millennia Pro 10s MOS 5 650 780 nm Power Output at the output maximum of the Rhodamine 6G tuning curve Pump laser Specified power Millennia Pro 5s 550 mW Millennia Pro 10s 1600 mW General Characteristics Spatial Mode TEMOO Beam Diameter at typical 1 4 mm Matisse output port Beam Divergence 2 mrad Linewidth lt 20 MHz rms Amplitude Noise 3 5 rms Beam polarization horizontal Requirements Pump laser Millennia Pro Series or similar Pump laser power 5 20W Matisse Laser Description 27 Ambient conditions constant temperature in the 20 25 C range non condensing humidity conditions Laboratory vibrational isolated optical table dust free air flow box Electrical 100 250 V max 2 5 Amps Computer control Windows 2000 or Windows XP system USB port Matisse Laser Description 28
10. Required Dye Solvents Required solvents to be used with the Matisse dye circulators are Ethylene Glycol EG Ethylene Glycol Phenyl Ether EPH and Propylene Glycol Phenyl Ether PPH because of their lubricant properties Other solvents will damage the dye circulators The dye concentration should be chosen in that way that at least 85 of the pump power is absorbed The following table contains solubility data g l for various dyes in the required solvents courtesy of Exiton Inc Solubility of Dyes in EG EPH PPH grams liter Dye Bo em em BPBD 365 Eo ma pm Eee Exalite 389 lw 227 f sa Exalite 392A lw jos fi Exalite 400E 65 sous 0 4 Coumarin 480 lom m Coumarin 515 B4 ss Coumarin 535 fiz6 Coumarin 540 js Pyrromethene 546 tow UM Pyrromethene 556 insol Pyrromethene 567 84 Pyrromethene 580 NN Pyrromethene 597 premio feo Matisse Laser Description 29 Kiton Red 620 Perchlorate 337 3 4 gt 95 10 3 DODCI DCM 0 07 2 6 1 4 e p pe km em fs um pe e mw p e CNN NC TN me fp ke p ie us LONE NN TN TM kmemse ps ws Matisse Reference Cell The Matisse Reference Cell contains a highly stable scannable optical resonator made of an INVAR rod serving as an external frequency reference in different frequency stabilization schemes for the Matisse S and X models The resonator itself is is evacuated The reasons are to prevent humidity related problems that degrade the piezo
11. 104 Pound Drever Hall frequency stabilization 42 Pound Drever Hall Waveforms 102 Powermeter 75 Precautions for the Safe Operation of Class IV High Power Lasers 11 Principle Laser Set up 31 Problems and Solutions 136 R RefCell Frequency Noise 94 RefCell Properties Measurement 95 RefCell Spectrum Analysis 96 RefCell Waveform 93 Remove Wavemeter 72 Required Dye Solvents 28 Return of the Instrument for Repair 133 S S Stabilization 88 Safety Precautions 11 Scan 106 Scan Device Calibration with Wavemeter 112 Scan Device Configuration 108 Scan Setup 106 Service Box 8 Index 138 Service Centres 134 Shut Down Matisse D 62 Shut Down Matisse T 62 Side of Fringe frequency stabilization 40 S Single Frequency Tunable Laser Physics 30 Slow Piezo Control Setup 92 Standard Units 7 Start Up 65 Start Up Matisse D 48 Start Up Matisse Ti Sa 47 System Components 8 T Thick Piezo Etalon Optimization 53 Thin Etalon 34 81 Thin Etalon and Birefringent Filter Optimization 54 Thin Etalon Control Position Options 83 Thin Etalon Control Setup 81 Thin Etalon Scan 82 Thin Etalon Signal Monitor 72 Transport 118 U Unpacking and Inspection 8 Using your own reference for stabilizing 46 V Version Changes 63 WwW Warranty 132 Wavemeter 112 Wavemeter Support 67 X X Stabilization 98
12. 3 59999 STOP J 0 001 Thin Etalon 3500 Measurement Progress Close The ControlScan parameter values see ControlScan Setup see page 109 for the active Scan Device see Scan Device Configuration see page 108 can be measured by executing a scan over a range of Scan Range with a speed of Scan Speed while calculating the position change for the Thin Etalon Thick Piezo Etalon and in the case of a Matisse TS DS or higher the Slow Piezo as well at the start and end During the scan all ControlScan parameters are set to zero Before executing the scan position the scan piezo at 0 3 set the PZETL baseline to 0 and optimize the BiFi and the Thin Etalon positions For a Matisse TS DS or higher also set the Slow Piezo to 0 35 and lock the laser Set Scan Range to 0 1 and Scan Speed to 0 001 and press the Measure button to start the scan All control loops have to be active otherwise the function will abort and give a corresponding warning The scan may take several minutes to complete It can be aborted with the Stop button After completion the ControlScan values for the various optical elements are calculated Pressing Set will set these values for the active configuration To make the change permanent you have to save the active configuration see Device Configuration see page 69 Matisse Commander 111 Motor Control Figure 70 Motor Control dialog The motors for the Thin Etalon and the Birefringent Filter can be controlled d
13. Commander installation if no appropriate software 1s already present on the computer Version Changes Matisse Commander 1 6 Matisse Commander 1 6 x rescales parameters with small values 1 by a factor of 10000 This is true for the FPZ and SPZ control loop gain parameters as well as for the PZETL modulation amplitude These parameters are rescaled only for display purposes The internally used values in the Matisse Controller stay the same Matisse Commander 64 Matisse Commander 1 8 Version 1 8 is based on LabVIEW 8 6 The dialog window for the piezo etalon was re programmed to accommodate the new feed forward parameters and to clarify the usage of the control The fast piezo dialog was modified to reflect the changes in the firmware General With the help of the Matisse Commander program you can manipulate the positions of the frequency selective elements and the settings of control loops respectively to achieve maximal stable single mode output from the Matisse laser device Moreover this program allows you to configure and execute scans over the laser s wavelength The following chapters ordered in analogy to the menu structure of the program gives you information on the various functions of Matisse Commander References to indicators or controls of dialogs are set in bold type The following subsections provides information concerning Matisse Commander in general Matisse Commander 65 Start Up Figure
14. Goto 0 0 0 3 Li 1 Uu 1 Li 1 t 1 Li 18000 18200 18400 18600 18800 19000 19200 19400 19600 19800 20000 Thin Etalon motor position Options Ol Figure 28 This window indicates the power reflected from the thin etalon as well as the total laser power for different positions of the thin etalon Basic Matisse Operation 60 Press Set and note down the wavelength frequency Now move the red cursor to the minimum of the next parabola of the Thin Etalon reflex signal and press Set again A comparison between the current and former frequency will normally reveal a difference with an absolute value of one FSR PZETL The change in frequency going from parabola to parabola in one direction is not necessarily monotonous There can be differences of up to one FSR TE Finding a parabola by going from one to the next one that has a minimal absolute value for the frequency difference is here the goal It should be possible to approach the desired frequency within a range of 0 5 x FSR PZETL for a standard configuration this corresponds to about 10 GHz If you cannot get close to this value please have a look at the full range of TE motor positions where there is a TE reflex signal and try to find a parabola with a frequency difference in the stated range Before doing the final approach to your frequency f you have to optimize the position of first the Birefringent Filter and then the Thin
15. Low Proportional Gain will result in a slow reaction from the controller but overshoot will be avoided Phase Shift This parameters controls the phase shift that is applied to the modulation signal that is applied to the tweeter The modulation of the piezo etalon results in a small modulation of the cavity length and subsequently of the emission wavelength A direct feedback of the modulation to the tweeter removes some workload from the tweeter control loop For an optimal setting of the Phase Shift parameter you require an external optical spectrum analyser Amplitude This parameters controls the amplitude of the modulation signal that is applied to the tweeter The modulation of the piezo etalon results in a small modulation of the cavity length and subsequently of the emission wavelength A direct feedback of the modulation to the tweeter removes some workload from the tweeter control loop For an optimal setting of the Phase Shift parameter you require an external optical spectrum analyser Changing the controls values has an immediate effect on the control loop To make changes permanent you have to save the active configuration see Device Configuration see page 69 Piezo Etalon Waveform Piezo Etalon Waveform E in pa SOT OUSAR US 5 E eee m a 2a 2 a a lt 1 25 1 1 1 1 1 200u 400u 600u 800u 968 75u Time sec 1 000 Modulation Frequency kHz Matisse Comma
16. signal have carriers that have a oscillation phase shift of 7 2 i e they are mathematically orthogonal like e g a sine and a cosine wave By applying a tunable phase shift to the EOM modulation signal before the mixer only the desired signal can then be filtered out The resulting theoretical Pound Drever Hall error signal in dependance of the laser detuning to the used non confocal resonator with a free spectral range of 1320 MHz and a Finesse of about typically 250 to 300 and a modulation frequency for the EOM of 20 MHz is shown below Theroretical PDH error signal for a resonator with FSR 1320 MHz Finesse 250 Modulation frequency Oyoq 20 MHz PDH error signal Detuning 0 MHz Frequency Stabilization 44 The interesting part of this graph is the relatively steep slope around the detuning of 0 MHz giving a very sensitive measure for the laser detuning in relation to the reference resonator resonance The fundamental principle producing this signal form is the following assuming the laser frequency is exactly resonant with the reference resonator then the beat signal terms of the fundamental frequency with the equidistant left sideband and the right sideband will cancel out because the sidebands have a phase difference of n giving a PDH signal of 0 If the laser is slightly off resonant the exited field in the reference resonator will have an optical phase shift in comparison to the laser field The s
17. 117207 777 222643 119207 Open File 776 418739 121207 775 616701 123207 Save 775 056293 125207 774 256857 127207 Y Save As Coefficients max deviation al 843 931003012 0 27432 x mean deviation a2 1 597 430108 7 0 086656 Set CalPar a3 Jj 1 115709E 6 l C Show Graph a4 j 198566 702983 The laser s wavelength can be calculated to an accuracy of 1 nm if there is an adequate calibration function for the Birefringent Filter motor positions The calibration table represents the relationship between wavelengths and motor positions that will be used to calculate a corresponding function To get data set the laser to a known wavelength and enter it into the table Get MOTBI Pos will retrieve the current MOTBI position and fill it into the active row Click into a row to make it the active one Sort will sort the table row in descending order of the wavelengths You can Delete marked rows Mark rows by selecting them with the left mouse button pressed With Open File Save Save As you can open or save files containing calibration table data Fit will fit the table data to the calibration function Wavelength WLOff WLFac sin 2 arctan LLen pos LOff Matisse Commander 80 The Coefficients have to fulfill certain conditions WavelengthOffset WLOff has to be greater than the maximum wavelength occurring in the table WavelengthFactor WLFac has
18. 1997 EN 61326 1 1998 Electrical equipment for measurement control and laboratory use EMC requirements We herewith declare in exclusive responsibility that the above specified instruments were developed designed and manufactured to conform with the above Directives and Standards Dr Sven H drich Gesch ftsf hrer Sirah Laser und Plasmatechnik GmbH Kaarst November 30 2005 CHAPTER 2 11 Safety Precautions Precautions for the Safe Operation of Class IV High Power Lasers The use of a dye laser system may cause serious hazards if adequate precautions are not taken Most of these hazards can be avoided by appropriate operation of the laser device However after a period of problem free operation many users tend to become careless with safety precautions Hence you should ensure that all safety rules described in the following section and of course those prescribed by law are observed The Sirah Matisse laser 1s operated in combination with a powerful pump laser Nd Y AG or Ar laser The laser power of the Matisse depends on the pump laser power and on the selected wavelength In any case the laser beam of the pump laser as well as the Matisse laser beam have an extremely high power density Hence both lasers are able to cause severe eye and skin damages Due to the high powers involved even scattered or specularly reflected laser light are sufficient to produce such injuries Furthermore absorbing and flammab
19. 23 ERR EI 0 207 0 104 0 007 Clear Chart m Thin Etalon Piezo Etalon Scan T Direction 2 Stabilization Thin Etalon Signal Piezo Etalon Baseline Scan Piezo Voltage Slow Piezo Voltage EME Tes nce ETET 0 0 25 05 0 125950 05 07 0 0 5 0 7 0 19398 J 0 00000 0 10000 Jj 0 35000 Your laser is now ready to work Basic Matisse Operation 58 Frequency Setting Setting the Matisse to a specific frequency needs a step by step setting and optimization of Birefringent Filter Thin Etalon TE and Thick Piezo Etalon PZETL In order to approach a specific frequency f you first need to set the Birefringent Filter Doing so will allow you to set the laser wavelength within a range of f 0 5 x FSR TE where FSR TE 250 GHz is the free spectral range of the Thin Etalon This is the standard value it might be different for your laser Older Matisse lasers were shipped with a TE with a FSR TE 130 GHz Then you need to set the Thin Etalon resulting in a laser frequency within the range of f 0 5 x FSR PZETL where FSR PZETL 20 GHz is the free spectral range of the Thick Piezo Etalon Finally tuning the PZETL will allow you to set the laser to the desired frequency f The recommended method for this last step is to scan the laser to the goal frequency instead of manipulating the baseline voltage directly Fine frequency adjustments of the Matisse are only possible by using an external frequency reference either
20. 58 Frequency Stabilization 39 Frequency Selective Elements 33 Frequently Asked Questions and Troubleshooting 129 G General 64 Goto Birefringent Filter Position 76 H Handling of Optical Components 114 l Installation 63 Installation Requirements 117 Integrate Wavemeter 72 Interactive Shell 71 K Key Navigation 66 L Laser Head Titanium Sapphire Models 16 M Main Window 68 Maintenance 114 Matisse Tools and Options 69 Matisse Commander 63 Matisse Commander 1 6 63 Matisse Commander 1 8 64 Matisse Electronics 127 Matisse Installation 117 Matisse Laser Description 15 Matisse Power Optimization 51 Matisse Preface 4 Matisse Reference Cell 29 Matisse DR Specifications 26 Matisse TR Specifications 24 Mirror Exchange 115 Motor Control 111 Motor Control Options 111 Motor Status 75 O Optical Alignment Procedure Matisse Dye 122 Matisse Ti Sa 118 Optical Alignment Procedure for the Matisse S Reference Cell 125 Optical Alignment Procedures 118 Optical Diode Unidirectional Device 38 Optical Set Up Matisse DR 19 P Piezo Amplifier Board Input Characteristics 127 Piezo Etalon 83 Piezo Etalon Control Setup 84 Piezo Etalon Description 35 Piezo Etalon Dither 37 Piezo Etalon Waveform 86 Pound Drever Hall Control Setup 100 Pound Drever Hall Error Signal Measurement 105 Pound Drever Hall Frequency Noise
21. Control LED indicator in the main window or ticking the Control On item in the RefCell Stabilization menu Troubleshooting If no lock can be obtained stop the RefCell Control loop Open Matisse gt Advanced Tools amp Options gt Control Loop Live View Set Protocol to FPZ The upper graph in this case will show the photo diode signal the red line corresponds to the FPZ Lockpoint Let this window open and switch on the RefCell Control loop Observe now the upper graph When you switch on the control loop and there is no lock then the slow piezo starts scanning the laser to find a resonance of the reference resonator You should see after a while in the upper graph the peaks of the resonator spectrum appear If you cannot see that the FPZ lock is setting in then you should decrease the Free Proportional Gain parameter in the Slow Piezo Control Setup see page 92 dialog This parameter determines the scan speed of the slow piezo If you see that the fast piezo control loop tries to lock to the setpoint but looses the lock quickly than you have to increase the fast piezo control loop parameters in the Fast Piezo Control Setup see page 90 e g multiply the values by a factor of 2 Optimizing the lock Matisse Commander 89 open the RefCell Properties Measurement dialog see page 95 Measure the spectrum and choose about half of the maximum peak signal seen in the spectrum graph as the new Setpoint for the fast piezo
22. a high resolution wavemeter or the atomic line or any other frequency selective phenomenon of your experimental set up The Matisse laser is delivered with a rough calibration for the Birefringent Filter This calibration is accurate enough to set the laser wavelength with an accuracy of about 1 nm to the desired value If the laser wavelength is already in the range of the calibration accuracy skip the next step Otherwise open the Goto Position dialog in the Birefringent menu of the Matisse Commander program Type the desired laser position in THz nm or 1 cm in the respective field You can choose whether to indicate the laser position in THz nm or 1 cm in the Display Options dialog in the Matisse menu For further tuning the Birefringent Filter and the Thin Etalon a procedure very similar to the one for the Thin Etalon and Birefringent Filter Optimization is applied For tuning the Birefringent Filter setting open the Birefringent Scan dialog and execute an corresponding motor scan A typical result is shown below for a description of the graph s elements and the signal forms see the Thin Etalon and Birefringent Filter Optimization section see page 54 Figure 27 Result of a Birefringent Filter motor scan Blue curve thin etalon reflex Red curve total Matisse power Both in arbitrary units Basic Matisse Operation 59 O Birefringent Filter Scan Thin Etalon Reflex Birefringent Filter Scan Total Po
23. and Finesse 17 800 600 400 200 0 200 400 600 800 Detuning MHz The Fast Piezo control loop works as follows any frequency deviation of the laser in relation to the reference resonator shown as blue arrows in the figure above will cause a change in the transmitted intensity green arrows This intensity difference to the desired transmitted intensity the setpoint in this case 0 5 1s then taken as an error signal for the FPZ control loop There is also a control loop for the Slow Piezo that manages the tasks for this piezo as explained above One drawback of this frequency stabilization method is its sensitivity to laser intensity noise Because an intensity change is taken as a measure for a laser frequency deviation intensity noise of the laser is wrongly interpreted as frequency deviations and actually transformed into real frequency noise To minimize this intensity sensitivity the Finesse of the used reference resonator could be increased i e the linewidth of the resonator decreased This would increase the laser frequency deviation sensitivity transmitted intensity change per frequency deviation and in this sense decrease the sensitivity to laser intensity noise But this will also decrease the catching range of the stabilization method defined as the maximal allowed frequency deviation without loosing the laser lock In this case it is about one quarter of the full linewidth of the reference resonator I
24. change per second see diagram below The Stop Mode determines if and when the scan stops at upper or lower limit Rising Speed MHz s and Falling Speed MHz s are about values for the frequency change per second These serve as a hint for the order of magnitude of the change Scan Range GHz gives the frequency range that corresponds to the scan range between Upper and Lower Limit To calculate the frequency quantities there has to be a conversion factor that can be set in the Scan Device Configuration see page 108 dialog Equal Speeds determines if the scan is symmetric in scan speed terms Figure 65 Scan Setup dialog Figure 66 Scan Timing 2 aer orci ca see een cecccccecccccsgpoec upper limit Ej rising falling 5 speed speed peo volts sec 3 a e oO 1 21 ert c AA T R ee lower limit time Matisse Commander 107 Scan Control switches the scan off or on Scan Mode allows you to define scan limits in three different ways Start Stop defines the scan by its upper and lower limits Start Range defines the scan by its lower limit and and scan range from which an upper limit can be calculated Position Range defines the scan using the current position and a scan range to calculate the following lower and upper limits current position range 2 and current position range 2 You can store different scan setups including Scan Mode to the Matisse C
25. control loop open the Frequency Noise display increase the Integral Gain for the fast piezo control loop multiply by factors of 2 until you see an increase in the displayed frequency noise There is a threshold for this parameter above which the control loop starts to oscillate and frequency noise rises strongly Decrease the Integral Gain until you find this threshold value Choose a value that is about 10 smaller than the threshold value If you cannot find a threshold you might have already started above it so decrease the Integral Gain until you will find a decrease in the frequency noise Matisse Commander 90 Fast Piezo Control Setup only available for Matisse TS DS and TX DX Fast Piezo Control Setup Integral Gain 999 98 Setpoint j 0 035 Lock Point Fast Piezo Control Figure 54 Fast Piezo Control Setup dialog In this dialog you determine the behavior of the Fast Piezo Tweeter control loop by setting the loop s parameters For optimizing the control loop s gain parameters see either the Stabilization see page 88 and X Stabilization see page 98 sections Integral Gain The Integral Gain determines the magnitude of the controller action that is applied to the fast piezo Low Integral Gain will result in a slow reaction of the piezo and not all perturbations of the laser will be compensated Excessive Integral Gain will result in overshoot and uncontrolled oscillations of the fast pie
26. dye or Titanium Sapphire laser five mirror sets which include the mirrors TM and M 1 through M 3 are sufficient to cover the entire wavelength spectrum see the Laser Description chapter Some effort has been undertaken so that the complete mirror change is possible in less than 30 minutes The focusing mirrors FM 1 and FM 2 are supplied with broadband coatings covering the entire tuning range of either the dye or the Titanium Sapphire laser Therefore changing the focusing mirrors is only necessary when changing from dye to Ti Sa set up or from Ti Sa to dye When changing from one mirror set to another the most simple procedure is to set the laser to a wavelength where the two mirror sets overlap Then operate the Matisse laser with medium pump power in order to have a stable output beam One by one unscrew all four mirrors to be changed and replace the removed mirror with the respective new one from the new mirror set After each replaced mirror the Matisse should restart lasing immediately and you should do a rapid optimization by tuning the exchanged mirror in order to come back or close to the initial power ATTENTION You are working and operation inside a laser Take great care to use the correct laser safety goggles and make sure that your work does not represent any danger for anyone else present in the laboratory The mirrors TM M 1 M 2 and M 3 are squeezed in metals rings which are then screwed in the massive body o
27. ee tme et eere EV e Pe Ted 77 Biretringent Filter Calibration Tables sce ue hate dete o ie ER deg 79 Thin Etalon eseguite ERRAT S Od UN Re eae eet un a uie ARIES 81 Thin Etalon Control Setup SERERE RT A Ge ERE ed E 81 Phin Etalon Scan o ettet o ERR Ge Bae seo hc eges adonde tit cee asda e IE ee ee 82 Piezo Btal ti eR SR ERRANT at ERN ete m Ru CI n CR I ERAT 83 Piezo Etalon Control Setup cie RETRAIT ee eS 84 Advanced Settings xii Re RR RR He RE a OR RIEN eeedei 85 Piezo Etalon W vetotm toe te ee tte aes bee aiite oe RS ee E 86 S Stabilizatioti epus uite ne atu Qi aee 88 Fast Piezo Control Setup ee RARE RR UAR Nt Re ee 90 Slow Piezo Control Setups ee esae ae RI e e e ae e NH cee 92 RetGell Waveforms ete te em pete e E ER rn I hee dit oon s 93 Retell Frequency Noise e et e SER Re OR E C ER EORR Re Ie We nau 94 RefCell Properties Measurement Ret ee FR GR Re ete HORE Xe SERE E D ees 95 X Stabiliz tion etes den atte xata e RR ONG NURSE EUe RE TIR EHE NN E RU Res ER habe ERR us 98 Pound Drever Hall Control Setup ssai ee ett ec CR DA T eee e e e E D et reed 100 Pound Drever Hall Waveforms eee eet e ERA TR IR AER OA aa 102 Pound Drever Hall Frequency Noise sess eene eren ener enne nnns 104 Pound Drever Hall Error Signal Measurement sse 105 DCAM ecc teme es Co Mae Deed e dede E A TLLA EU SEO C DL TTE RU stobscaghteans Convers 106 Siva TEE 106 Scan Device Configuration eee RR p
28. etalon motor is running LED 18 Birefringent filter error Lights up when an error condition is present at the etalon motor controller unit LED Figure 6 Rear view of the Matisse electronics box 1 X1 Connector This mixed signal sub D connector is used to connect the laser head to the control unit Matisse Laser Description 23 X2 Connector This mixed signal sub D connector connects the thin etalon stepper motor with the control unit X3 Connector This mixed signal sub D connector connects the birefringent filter stepper motor with the control unit AC Input Connector This connector also holds the fuse for the unit Rating 1 6 A 250 VAC Matisse Laser Description 24 Matisse TR Specifications This section summarizes the specifications of the Matisse TR laser Please note that specifications are subject to change without notice Tuning range Pump laser Optics set Output range Millennia Pro 10s MOS 1 700 780 nm Millennia Pro 10s MOS 2 750 870 nm Millennia Pro 10s MOS 3 860 990 nm Power Output at approximately 780 nm Pump laser Specified power Millennia Pro 5s 800 mW Millennia Pro 10s 1800 mW General Characteristics Spatial Mode TEMO00 Beam Diameter at typical 1 4 mm Matisse output port Beam Divergence 2 mrad Linewidth lt 10 MHz rms Amplitude Noise 1 5 rms Beam polarization horizontal Requirements Pump laser Millennia Pro Series or similar Matisse Laser Description 25
29. idealized light ray etc The simplest laser beam has a transverse intensity profile in form of a Gaussian distribution Second they can have a very high temporal coherence 1 e the field has a relatively small frequency spectrum For the latter property some conditions have to be fulfilled Optical resonators have discrete resonances with well defined frequencies separated in the case of a ring resonator by a frequency difference of Av c d c velocity of light d mirror distance this is called the Free Spectral Range FSR These resonances are called resonator eigen modes If you have a gain medium with a relatively small bandwidth compared to the FSR of the optical resonator and one of the resonator modes frequencies coincides with the center frequency of the medium your laser will emit radiation only with just this frequency you then have a single mode laser In the case of the Ti Sa with its very large gain bandwidth a vast number of modes could in principle oscillate for any practical resonator length To achieve single mode laser operation for Ti Sa or dyes additional frequency selective elements have to be introduced into the resonator These elements will be explained in detail in the next section Single F requency Tunable Laser Physics 32 Another important aspect for single mode laser operations is to choose a ring laser geometry instead of a standing wave resonator configuration With electromagnetic standing waves
30. no lock can be obtained stop the RefCell Control loop Open Matisse gt Advanced Tools amp Options gt Control Loop Live View Set Protocol to FPZ The upper graph in this case will show the PDH error signal the red line corresponds to the FPZ Lockpoint Let this window open and switch on the RefCell Control loop Observe now the upper graph When you switch on the control loop and there is no lock then the slow piezo starts scanning the laser to find a resonance of the reference resonator You should see after a while in the upper graph PDH error waveforms appear If you cannot see that the FPZ lock is setting in then you should decrease the Free Proportional Gain parameter in the SPZ Control Setup see page 92 dialog This parameter determines the scan speed of the slow piezo If you see that the FPZ control loop tries to lock to the PDH error signal but looses the lock quickly than you have to increase the FPZ PID loop parameters in the FPZ Control Setup see page 90 e g multiply the values by a factor of 2 Optimizing the lock open the Frequency Noise display goto the Fast Piezo Control Setup see page 90 dialog increase the Integral Gain for the fast piezo control loop by factors of 2 until you see an increase in the displayed frequency noise There is a threshold for this parameter above which the control loop starts to oscillate and frequency noise is increased Decrease the Integral Gain until yo
31. saturation effects in the Ti Sa crystal Frequently Asked Questions and Troubleshooting 131 Start using the translation stage for mirror FM 2 Decrease the distances in steps of one full knob turn At each step compensate the changes of the beam path in the resonator by using mirror TM Observe the mode pattern on the laser housing to see if it is improves Do not make more than 4 to 6 steps When you find a good position you can use FM 1 and FM 2 in parallel decrease FM 1 and increase FM 2 by the same amount to shift the position of the beam waist in the crystal to further improve the mode quality Changes of the beam path introduced by a position change of FM 1 are compensated with mirror M1 Dye Matisse Changing the pump focus position can mitigate saturation effects in the dye jet Increase the distance between PM and dye jet by turning the translation stage knob of the pump mirror in steps of 1 8 turns Compensate for pump beam path changes with two adjustements screws of the pump mirror Observe the mode pattern on the laser housing to see if it is improves With increasing distance you will probably experience decreasing power If the pump mirror position change does not porduces the desired results start changing mirrors FM 1 and FM 2 as described for the Matisse Ti Sa case Instead of changing the position of one full turn per step use one half turn per step CHAPTER 12 132 Customer Service Warranty Sirah l
32. size at different positions within the ring cavity Place the beam overlap tool between the output coupler M1 and the Brewster window at the output Make sure that the fluorescence spot originating from FM1 has got the correct height To adjust the height slightly adjust the height of the beam path through the two pinholes using PM1 and PM2 Place the beam overlap tool between the Piezo Etalon Thick E and the TGG plate TGG Adjust the beam height with the vertical adjustment of the tuning mirror mount TM Remove the beam overlap tool and using a small strip of paper make sure that the beam passes through the TGG plate and hits the middle of M3 This is especially important for the actively stabilized Matisse versions because there M3 is rather small 10 11 12 Matisse Installation 122 Superimpose the propagation paths of the two fluorescence spots the beam path from FMI to the output coupler M1 serves as the fixed path to which the beam from FM2 will be aligned using M1 and M3 Put the beam overlap tool between the Birefringent Filter BiFi and the output coupler M1 Bring the spot from FM2 closer to the fixed spot using only M3 Then put the beam overlap tool between FMI and the Thin Etalon mount Thin E Overlap the spot from FM2 with the fixed spot using only M1 Put the beam overlap tool back to the first position between BiFi and M1 and repeat the procedure To distinguish between the two spots as they ge
33. the EOM Fast Offset and EOM Slow Offset controls offsets in the fast and slow control signal branch for the intra cavity EOM can be compensated A scan over the cell s piezo actuator voltage is performed within an interval determined by Scan Upper Limit and Scan Lower Limit values are in a range of 0 to 0 7 The Sampling Points parameter gives the number of points used to display the internal waveform It cannot be higher than 512 The Sampling Mode decides which characteristics of the full internal waveform at the ADC the DSP is looking for finding Maxima Minima or computing the Average The two red cursors at the edges of the graph can be dragged inside or outside to adapt the scan limits interactively to have an optimal view on the corresponding waveforms The Autoscale Y Axis property determines whether to automatically adjust the maximum and minimum values of that axis If the property is set to false you can manually adjust these values by clicking onto the axis with the left mouse button and entering new numbers for the minimum and maximum values Matisse Commander 104 Pound Drever Hall Frequency Noise Figure 63 PDH Frequency Noise display only available for Matisse TX DX and TX DX light PDH Frequency Noise Frequency Deviation 0 08 FSR RefCell MHz 0 06 J 11320 0 04 Finesse 0 02 1260 E pi PDH Error Signal 0 02 Maximum Intensity 0 04 J 0 231323 0 06 PDH Error Signal 3 Minimum Int
34. the baseline is around zero The Phaseshift determines the phase between the 20 MHz sine modulation and the detector signal This phase will determine the shape of the PDH error signal Choose a value that results in an symmetric error signal with a steep slope in its center The Attenuator value determines how strong the intra cavity EOM will react on deviations from the zero crossing of the PDH signal All above mentioned quantities have a range of 0 to 255 except the Attenuator which has a range of 0 to 63 Smaller or bigger values will be coerced to the corresponding limit value Figure 61 Drever Hall Setup parameters Matisse Commander 101 PDH Multiplexer Input shows which signal is currently as output from the multiplexer Modulation On indicates sets the status of the 20 MHz sideband generation and EOM active shows sets the control status of the intra cavity EOM Pound Drever Hall Control Basic Advanced EOM Slow Offset 127 A EOM Fast Offset 129 Advanced Parameters Pound Control advanced With Fast and Slow Offset offsets in the fast and slow control signal branch for the intra cavity EOM can be compensated TX light remark Fast and Slow Offset and Attenuator are disabled Matisse Commander 102 Pound Drever Hall Waveforms Figure 62 Waveforms dialog PDH only available for Matisse TX DX and TX DX light Pound Drever Hall Waveforms x Scan Upper Limit Jio 127639
35. to be negative Good start values might be maximum wavelength in table 50 for WavelengthOffset 400 for WavelengthFactor 2e 6 for LeverLength LLen and 100000 for LinearOffset LOff On opening the Calibration Table dialog the Coefficients indicator gives the current function parameters WLOff WLFac LevLen LinOff used by the Matisse controller After a fit is executed it will contain the newly calculated numbers together with the Maximum Deviation and the Mean Deviation of the fit result If Show Graph is ticked a graphical representation of the fit result and its errors is shown after a fit has been executed Set CalPar will program the displayed Coefficients into the Matisse controller To make this change permanent you have to save the active configuration see Device Configuration see page 69 available only with wavemeter support Birefr Scan will open the Birefringent Filter Calibration Table Birefr Filter Scan see page 80 dialog where a scan over the Birefringent Filter motor positions is executed simultaneously measuring the wavelength with the help of an external wavemeter Birefringent Filter Calibration Table Birefr Filter Scan only available with wavemeter support In this dialog a scan over the Birefringent Filter motor positions can be executed while simultaneously measuring the current wavelength with the help of an external wavemeter The scan start and end positions and increment can be set in
36. tube in your laser service box that should be installed between pump and Matisse laser to minimize perturbations caused by air flows Matisse Installation 123 Position the Matisse on your optical table so that the pump beam passes through the entrance opening and runs parallel to the Matisse housing The focusing pump mirror PM needs to be hit exactly in the middle Its distance should be about 40 mm from the pump spot in the dye jet The transmitted pump light should hit the beam dump next to the folding mirror FM 1 With these conditions fulfilled the beam may not pass exactly through the middle of the entrance opening If the height of the beam on PM is not right you may need to adapt the Matisse height loosen the counter nuts on the Matisse feet wrench size 17 mm and the adjust the height by turning the nuts near the bottom of the feet wrench size 10 mm One revolution corresponds to 2 mm of vertical movement Make sure you turn each of the nuts by the same amount to avoid instabilities and tilting of the Matisse housing Finally gently tighten the counter nuts without holding the nuts at the bottom of the feet For Matisse operation the pump beam path as well as the ring cavity beam path have to run at a height of 60 mm above the baseplate This height is marked by the center of the beam overlap tool see figure above if it is placed on the baseplate Set the distance between the two folding mirrors FM 1 and FM 2 to
37. 2 Phase Scale Factor Offset Off Set Intensity J 1255 8 0 180202 0 176692 Phase Offset J 2 9694 Set RefCell Prop The Peak Table contains the position amplitude and the full width at half maximum FWHM value for each found transmission peak of the RefCell spectrum measured in the RefCell Properties Measurement dialog see page 95 If more peaks are found than there are clearly visible ones increase the value for Peak Width until the correct number of peaks appear in the Peak Table With the information in the Peak Table it is possible to calculate the RefCell Finesse The Maximum Intensity and Off Set Intensity of the spectrum are given as well Airy Fit tab A Fit for the RefCell spectrum can be made according to the following function for the transmitted intensity Intensity Scan Piezo Position Offset Amplitude 1 2 x RefCell Finesse x Y x sin Phase Scale Factor x Scan Piezo Position Phase Offset 2 The best fit result is shown in the graph of the RefCell Properties Measurement dialog see page 95 If the fit does not lead to reasonable fit parameters press again Fit and see if the result improves If not press Init to initialize the start parameters again change the Phase Offset and repeat the fitting procedure Matisse Commander 97 Set RefCell Properties stores the calculated RefCell Finesse the RefCell s FSR the Maximum and the Off Set Intensity into the Matisse Commander s
38. 30 Device Not Found dialog At the start up of the program Matisse Commander will try to detect the presence of a Matisse laser device either with the help of information in the Matisse Commander s configuration file Matisse Commander ini or by directly accessing USB devices that have the correct Manufacturer and Model ID If no Matisse laser can be located the following dialog will appear requesting you to power up the Matisse controller box and restarting Matisse Commander or to choose the Dummy Mode E Device not found Could not find a Matisse device Please restart the Matisse hardware Exit Dummy Mode The Dummy Mode is useful for getting familiar with the control program without needing an actual physical device or using it as a test environment for software plug ins for the Matisse Commander see the Matisse Programmer s Guide for further details This mode tries to simulate the Matisse controller box with an idealized laser but it does not completely implement all device commands so you might encounter error messages in some dialogs Error Dialog Figure 31 Error Dialog Key Navigation Matisse Commander 66 Error Error Message Matisse Error 50 motor error Display Off Command MOTBI Command Motor Error 7 position out of range Error Stack Matisse API Motor Get Status vi lt Matisse API Y If an error occurs this dialog will display basic error information Details will pro
39. 445 0 24475 0 245 Scan Position mae Min Mex 0 13 1897 0 134033 Set Min Max Close i Measure will perform a sampled scan with a range of Scan Range and an increment of Scan Increment with the current Scan Device either RefCell or Slow Piezo while measuring the PDH error signal value For the scan to be successful the positions of the Thick and Thin Etalon have to be optimized and the corresponding control loops have to be active beforehand In the case of the RefCell as scan device the RefCell control loops will be switched off automatically After closing the dialog the original control loops status will be restored Set Min Max will store the Min and Max values of the PDH error signal that are needed for the PDH Frequency Noise display see page 104 Matisse Commander 106 Scan Scan Setup Scan Setup Available Scans Position Rising Speed V s Rising Speed MHz s DEVICE j 10 31095 J 0 005 s 0 05 Start Falling Speed V s Falling Speed MHz s Set E 10 25 0 005 0 05 e save Stop Range Scan Range GHz Jj 0 45 0 2 0 Scan Mode l Start Stop equal Speeds Scan Control Stop Mode C ej increase voltage stop at neither limit This dialog determines the scan behavior Position Start and Stop have a range of 0 to 0 65 and set the voltage applied to the scan piezo and the upper and lower limits of the scan respectively Rising Speed V s and Falling Speed V s are the voltage
40. 7000 258000 259000 260000 Birefr Filter motor position Options The blue curve has a step function form Within each step the Birefringent Filter might be set to an arbitrary position without changing the Matisse laser frequency If you change the motor position from one step to the next one the Matisse frequency will change normally by one Free Spectral Range of the Thin Etalon see the Single Frequency Tunable Laser Physics see page 30 chapter for more details Figure 23 Move the Birefringent filter to the position correspoding to maximum laser power without hopping onto another step of the blue curve Basic Matisse Operation 55 The Birefringent Filter position can be set by moving the red vertical cursor shown in the graph Once the acquisition is finished move the mouse cursor on the red vertical line and drag the line by clicking on it with the left mouse button pressed Move the filter to about the center of the step of the blue curve where the original motor position was located so that it coincides with the corresponding local maximum of the total laser power red curve as shown in the figure below Click on Set in order to physically move the Birefringent Filter motor Thus the total laser power will be optimized without any influence on the current wavelength You need to hit Set even if the default position of the red cursor is the position you want to keep because otherwise the Birefringent Filter will s
41. Commander extension is available on request Frequency Stabilization 46 Using your own reference for stabilizing Instead of using the reference cell that comes with the stabilized Matisse versions you can also use your own reference generating an adequate error signal for the laser frequency deviation For this the DSP controller card has an external input for your error signal so you can take advantage of the control loop logics already implemented for the Fast and Slow Piezo The section DSP Input Characteristics see page 127 gives the technical details and constrains for your signal When you connect your error signal to the DSP s external input and set the switch from Intern to Extern you replace the internal error signal from the Matisse Reference Cell with your own signal There is exactly one control loop DSP task that uses this error signal to act on the Fast Piezo So you can either stabilize on your reference or on the Matisse reference cell but not on both at the same time You have to adapt the Fast Piezo and Slow Piezo control loop parameters to the characteristics of your error signal CHAPTER 6 47 Basic Matisse Operation The present chapter deals with the standard start up procedure This procedure applies for systems which are well installed and have been used under the same operating conditions in the near past This holds true if you switch off your system in the evening and switch it on again th
42. Etalon as described in the Thin Etalon and Birefringent Filter Optimization section see page 54 Finally scan the laser to the desired frequency see the following section In most cases the procedure described above allows a direct approach to the selected frequency In some cases however the interaction of Birefringent Filter Thin and Piezo Etalon leads to an unstable optics configuration In this case more stable operation can be achieved by tuning the Birefringent Filter and Thin Etalon settings described above more than once Basic Matisse Operation 61 Frequency Scanning Figure 29 Scan Timing The Matisse is scanned by acting on the logical scan piezo For the Matisse R version this is the long travel piezo the tuning mirror TM is mounted on for the stabilized Matisse versions this is the reference cell piezo Before starting a scan you need to optimize the Birefringent filter the Thin and the Thick Piezo Etalons at the scan reference frequency as described in previous sections Take care to activate automatic tuning of the Thin and Thick Piezo Etalons by clicking on TE Control and PZETL Control and additionally for the stabilized versions to enable the reference cell lock in the Matisse Commander window To define a scan open the Scan Scan Setup menu Scans are defined by the current Scan Piezo Position Start lower limit and Stop upper limit positions that have a nominal voltage range of 0 to 65 Set the
43. Loop Principle detected amplitude variation detected amplitude variatior dither signal dither signal Having the etalon aligned to the cavity mode is essential not only for getting the maximum laser power but also in the case of scanning the laser Scanning is achieved by changing the laser resonator length continuously with the help of one of the resonator mirrors mounted on a piezo actuator So when the laser frequency changes the piezo etalon control loop will make sure that the piezo etalon s mode frequency will follow by adapting the thickness of the air gap Single F requency Tunable Laser Physics 38 Optical Diode Unidirectional Device Because the Matisse is a ring laser two counter propagating modes with the same frequency could co exist To prevent this an optical diode is also part of the optical set up It consists of a TGG crystal plate mounted in a strong magnetic filed that will rotate the polarization vector of the electric field by some degrees irrespective of the propagation direction Faraday effect The M3 Matisse mirror of the three mirror assembly is an out of plane mirror causing also a rotation of the polarization vector of the electric field but this time the direction of the rotation depends on the propagation direction For the counter clockwise running laser mode the effects of this mirror and the optical diode are canceled out For the clockwise running mode the effects sum up so that this mode will
44. Matisse User s Guide Version 1 8 Sirah und Plasmatechnik GmbH Contents Matisse Preface 4 Environimetntal Specifications 5 au eet e Ug d ae E RU RI E RO uuds 6 CE Electrical Equipment Requirements ssssssssssesseeeeenenerenerenenn enn ener nnne nnne 6 Environmental Specifications sesse ar eere ean e E raaa e e eE A a asis 6 Standard Units ME 7 Unpacking and Inspection 5e anite tti te ot die e e a eeu eget 8 System ComponeTniss avoien oie Hr in Cus arripere b re teo M ett e c ie ped es 8 Semice BOK m 8 CE Declaration of Conformity za oen o Hui repa M b dicet e d e doa 10 Safety Precautions 11 Precautions for the Safe Operation of Class IV High Power Lasers eee 11 Dangers Caused by Laser Dyes and Solvent ccecccescceseesseeeeeseeeseeeeceseeeseensecesecsaecnaecseecaeensecseecseeeeneees 13 Focused Back Reflection Dan ger oi 0 5 nut Hones Cete e e Ade awe ed 14 Matisse Laser Description 15 Laser Head Titanium Sapphire Models sse enn enne nnns 16 Optical Set Up Matisse DR 5 ettet NE IE ERR TAS DES heen Pee E VOR esas 19 Controls Box Front and Rear Panel Features sse ener 21 Matisses FR Specifications oT IRE D PRENDE TRUST ont eee aes eee eee 24 Matisse DR Specifications eere HIER IET Ree E STENT TRENDS ge eee 26 Required Dye Solvetits 4 tete teet et vci mia eee e BOE etes 28 Matisse Reference Celb4 s sach satietate eme a n tbe E i 29 Single Fre
45. Signal 1s 0 0818 The Thin Etalon s reflex signal is displayed to be used when adjusting the reflex on the corresponding detector Integrate Wavemeter Integrate Wavemeter If you possess a Wavemeter and a corresponding software plug in see Matisse Documentation Matisse Control can use the device to enhance its Functionality When you press OK Wavemeter related data will be added to Matisse Control s configuration File and the control program will terminate After you have restarted Matisse Control the new menu Wavemeter will be available If you have a wavelength measuring device wavemeter available the functionality of the Matisse Commander can be enhanced provided that a corresponding software plug in can be created Further information concerning the software plug in can be found in the Matisse Programmer s Guide Remove Wavemeter Remove Wavemeter Presssing OK will remove all Wavemeter related data from the Matisse Control configuration file and the control program will terminate The integrated support for a wavemeter Integrate Wavemeter see page 72 will be removed i e the Matisse Commander program will not search for wavemeter plug ins at the start up Figure 39 Control Loop Live View Dialog Matisse Commander 73 Control Loop Live View Control Loop Live View Protocol Jj PZETL 1069 SetPoint Time o Any zit Pu Lu 0 2322 45 Period ms
46. The frequency stabilization schemes described before will give small laser linewidths 1 e frequency fluctuations on time scales of several 10 or a few 100 ms are reduced When you look at the frequency behavior on time scales of several 10 s or minutes and some hours the center frequency of the laser can drift in the order of some 100 MHz depending on the ambient conditions of the reference cell environment The drifts are due to temperature changes or piezo actuator relaxation processes acting on the optical properties of the reference cell To compensate these drifts an absolute frequency reference like an atomic resonance is needed The following figure shows a possible Matisse setup using the absorption fluorescence signal of a gas exited by the laser radiation as an error signal for the laser frequency detuning This signal is digitized by a DAQ card and processed by a software extension of the Matisse Commander control program In reaction to the error signal this software extension will act via the Matisse controller on the RefCell piezo actuator to keep the master resonator on the atomic resonance Drift Compensation PC Extension Controller Pump Laser Small Linewidth This setup scheme does not need a stabilized Matisse to work The drifts of lasers of the Matisse R type can be compensated as well The LabVIEW framework for the Matisse
47. able Factory and User configurations Factory configurations are preset and can not be changed It is possible to have several user configurations that can be newly created changed and saved There is a default configuration that 1s used at every start up of the Matisse controller To fully administer the various device configurations see Device Configuration Administration see page 70 This menu lets you make the active configuration the default one save the active configuration to the Matisse DSP board or to a human readable text file Also you can load configurations from a file Note Saving the active configuration will interrupt the execution of the Thick Piezo Etalon control loop Figure 34 Device Configuration Administration dialog Matisse Commander 70 Device Configuration Administration I Device Configuration Administration Active Configuration USER ONE Default Configuration USER_ONE Device Configurations Factory Configurations FACTORY_THREE FACTORY_TWO FACTORY_ONE 2 User Configurations USER_ONE USER_THREE USER_TWO The Device Configurations control lists all available configurations differentiated by Factory and User configurations for a description what configuration means see Device Configurations see page 69 There is also the Active and the Default Configuration displayed With Activate or Make Default you can give any of the available configurations the corresponding status Onl
48. about 113 115 mm The distance between the pump spot in the dye jet and FM 1 should be about 50 52 mm and the distance between the pump spot and FM 2 should be about 62 64 mm In the service box you will find two pin holes that can be set on FM1 and FM2 Put the pin holes on the mirror side facing the dye jet Set the pump laser to the lowest possible output and put the beam overlap tool between FMI and the dye drain mount Adjust the height of the transmitted pump beam using the vertical adjustment of PM so that the center of the spot is in the middle of the beam overlap tool Make sure that the pump beam has got the correct polarization p polarized Loosen the plastic screw at the half wave plate on the Matisse input and rotate it so that the power of the pump beam reflex off the dye jet visible on the little beam blocking sheet on the dye nozzle mount is minimized The nozzle height should be adjusted so that the pump spot is about 3 to 5mm underneath the nozzle Adjust the nozzle s horizontal position so that the dye jet enters the drain tube at reasonable distances from the tube edges to avoid turbulences in the drain Increase the pump power to max 1 W Locate the two fluorescence spots one going from FMI to the output coupler M1 and one going from FM2 to the beam displacement rhomb PS Make sure that their height is 60 mm by putting the beam overlap tool between PS and the tuning mirror TM and then between M1 and the output o
49. ae a e e e Re resedit ne Be te edd 108 ControlScan Setup is ae ge tete a Rae dte Cul RG RA e det e ua t ete 109 ControlScan Values Measurement ccccccsseessesseeesceseceeceseceseesecesecesecaecaaecsaecaeeeaeeeaeeeeeeeeeenreees 110 Motor Control 21m treinta mei DU ia A t 111 Motor Control Options sessi enne enne entrent rene trennen nre a aeea ni 111 Mayemetet onerati ei GOL SOT OR PIP ARTI tU Pe b e t ip pe e ES 112 Scan Device Calibration with Wavemeter sese eene eene entere n nennen en 112 Maintenance Contents Handling of Optical Components 5 25 nne dep c ee b n e He pr e eer Mirror Exchange Matisse Installation Installation Requirements i reno dene RR Rate AS RR RE A E RUNS Transport Optical Alignment Procedures ci iode Ee e RE CORE e edn ee x Optical Alignment Procedure Matisse Ti Sa sssssssssssssseseseeeeeneenen ee enne Optical Alignment Procedure Matisse Dye sss ener nnns Optical Alignment Procedure for the Matisse S Reference Cell esses Matisse Electronics DSP Input ChatcCtekiSflCSz 53st fe tr i RE a eo eso atado aeu due mates Piezo Amplifier Board Input Characteristics eese Fast Piezo Amplifier Board Input Characteristics cccccsccesceeseeesecsceeseeeseeeeeeeeceseeeeenseeesecaeensecaaeeaeenaes Frequently Asked Questions and Troubleshooting Cust
50. aling of the two control loop gain parameters with the control loop setpoint set with the Thin Etalon Scan see page 82 procedure Changing the controls values has an immediate effect on the control loop Thin Etalon Scan Figure 50 TE Control Position dialog Matisse Commander 82 Thin Etalon Scan 0 4 0 8 JONI POL Thin Etalon Reflex 0 17j 1 i 1 1 1 l 1 1 1 170 7 13750 14000 14250 14500 14750 15000 15250 15500 15750 16000 16250 16500 16750 Thin Etalon motor position In this dialog a scan over the Thin Etalon motor positions can be executed to set the control position for the Thin Etalon control loop Two signals are recorded the total laser power and the intensity of the thin etalon s reflex The scan is centered around the current TE motor position The scan range scan increment and the initial motor position can be set in the Thin Etalon Control Position Options see page 83 press the Options button or F2 The current motor position is shown as a cursor red line within the graph in the Thin Etalon Scan graph and in the Motor Position control You can change this position by changing the position control and pressing Goto Pressing Start will execute the scan that can be aborted by the Stop button Set will move the motor to the position the cursor in the graph points to and the control goal value will be set It is the ratio of the thin etalon s reflex and the
51. are deactivated Powermeter Figure 42 Powermeter Motor Status Figure 43 Motor Status Display Matisse Commander 75 P Powermeter 0 4 0 5 0 6 0 2 0 3 0 7 0 8 Averaged Power 1s 0 6996 The powermeter displays the total laser power and can be used for adjusting purposes Motor Status MOTTE Position MOTBI Position 90000 180000 lm Running Gm Running EN Error EN Error Show Clear Error This windows display the current position and status of both the Thin Etalon and the Birefringent Filter motors It is updated every 500 ms and runs in parallel to the main program Show Clear Error will show you an error dialog indicating which motor error occurred and clear the error status if the Thin Etalon or the Birefringent Filter motor controller are in an error condition Matisse Commander 76 Display Options Display Options Position Display Made nm Precision Display On Figure 44 Display Options dialog The Position Display Mode control determines the physical unit the program uses to display the position of the laser device Precision sets the number of digits to be shown after the decimal point It has only an effectif a wavemeter is used otherwise the precision is fixed to one digit Display On switches the controls and indicators in the Main Window see page 68 on or off Birefringent Filter Goto Birefringent Filter Position Birefingent Position Figure 45 Bi
52. asers are thoroughly designed and assembled and we take great pride in the reliability of our instruments Nevertheless each precision instrument will need occasional service Therefore our aim is not only to provide high performance scientific instruments but also to offer an excellent after sales service In case of any problem please feel free to contact your local service centre Addresses may be found at the end of the present chapter You will need your instrument model and serial numbers available when you call Service data will be promptly supplied Warranty conditions are defined in our General Sales Conditions They may be modified by agreements made in your specific sales order In case of any conflict between documents the terms and conditions of the sales order shall prevail Sirah warrants that the products except optics shall be free from defects in materials and workmanship under normal use and service for a period of twelve 12 months from the date of installation or from 30 days after shipment from Sirah Optics and filters are warranted for 90 days This warranty is subject to Sirah products being installed maintained and operated in accordance with the operating and maintenance instructions accompanying the shipment Warranty shall be void if Sirah products are modified by the customer or used in other than the recommended manner or applications In no case shall Sirah be liable for consequential or special damages
53. ation If the cavity mirror optimization does not give you the expected or usual laser power within a range of 10 to 15 for the current wavelength it may be necessary to adjust the Piezo Etalon Before adjusting this etalon with the help of the two big micrometer screws as shown in the Matisse Ti Sa Optical Setup see page 16 note down the current setting using the scale on the upper side of the two screws The upper screw determines the vertical adjustment the lower one the horizontal one Start adjusting the lower horizontal screw Observe the Matisse power on your power meter Then carefully turn the lower micrometer screw to maximize the Matisse power There should be one position where the laser power peaks There might be a slight hysteresis so maximize the power twice approaching the peaking point from the two different directions to see which direction gives the maximum power Adjusting the upper vertical screw can reveal the existence of two different peaking points having similar laser power not due to hysteresis Use the one with maximum power Here also a slight hysteresis may exist so apply the same procedure as described above If you turn too much the Matisse will stop lasing In this case immediately come back to the starting position in order to re obtain laser operation and re start optimizing Basic Matisse Operation 54 Thin Etalon and Birefringent Filter Optimization Figure 22 Result of a Biref
54. back side beam and use only the front side beam for the following procedure Place a screen e g a business card behind the reference cavity Use an infra red viewer to look at the screen You should see one or several laser spots Try to concentrate these spots into one by adjusting mirrors BS and M1 Figure 81 Waveform display RefCell Matisse Installation 126 If you have not already done so switch on the Matisse electronics box Start the Matisse Commander program and choose Ref Cell Waveform from the Ref Cell Stabilization menu Adjust the position of the reference cell detector diode so that you have maximum signal for the waveform The detector is screwed on an L mount loosening the screw allows you to adjust the detector s vertical position The L mount in turn is screwed on the reference cell s base plate loosening this screw allows you to adjust the horizontal position If you have trouble getting a signal at all remove the neutral glass filters in front of the diode Keep in mind that without the filters the detector will be probably saturated resulting in a flat line waveform with high intensity Annotation The waveform graph in the Ref Cell Waveform dialog 1s autoscaling the signal Y axis by default You can change this behavior by deactivating the Autoscale Y Axis control Click then on the maximum and minimum values for the y axis and directly type in new values RefCell Waveform Scan Upper Li
55. cal modulator is used for fast change of the optical path length of the ring cavity The effect is used for high bandwidth correction of the Matisse s emission wavelength Note The device is only present in the Matisse DX TM Tuning Mirror The exact emission wavelength of the cavity is determined by it s length The tuning mirror is attached to a long stroke piezoelectric actor to allow the selection of this wavelength This device is used for low bandwidth woofer correction of the Matisse s emission wavelength when active wavelength control is enabled only available in Matisse DS and DX models Matisse Laser Description 21 DI Integral Diode The lock in control for the piezo etalon requires the measurement of the temporal behaviour of the integral intensity of the ring laser For this purpose the leak intensity on the backside of the out of plane mirror M2 is used DE Etalon Diode The control loop for the thin etalon requires the measurement of the back reflection of the entrance surface of the etalon This diode measures the reflected intensity Controls Box Front and Rear Panel Features Figure 5 Front view of Matisse control box 1 Power switch Turns the entire unit On and Off 2 Voltage indicators Light up when the respective voltage is available in the control unit LED 3 DSP signal input select Selects the internal or an external signal source for the digital signal processor DSP 4 DSP external in
56. ck knobs on the opposite side of the two silver colored micrometer screws of the Piezo Etalon Observe the wrong laser spot on the laser housing and turn the screws to get rid of it Instead of the laser spot you will see two fluorescence spots which relative horizontal and vertical position to each other will change with turns of the corresponding screws There is normally a trade off situation for the adjustment of the Piezo Etalon orientation the closer the etalon gets to the perpendicular case the higher is the laser output power If it is too close the output for the counter clockwise running mode will sharply drop As a rule of thumb introduce a vertical separation of the fluorescence spots by 5 to 10 mm I experience spatial instabilities spatial mode fluctuations of the laser beam Frequently Asked Questions and Troubleshooting 130 A laser pumped with higher pump powers might show spatial mode instabilities 1f not adjusted well enough or because of saturation effects in the lasing medium causing decreased power and making single mode operation difficult You can easily check the laser mode quality by looking at the laser spot of the transmitted light of one of the laser cavity folding mirrors Ti Sa Matisse Look at the spot coming from mirror FM 1 and going through mirror PM2 Optical Setup Ti Sa see page 16 on the inner laser housing about 7 cm left to the pump beam entrance The laser spot is horizontally el
57. ckness of 280 um for MOS 1 and MOS 3 the thickness is 325 um The frequency range in which lasing modes could exist is narrowed down to several 100 GHz by the Birefringent Filter This filter serves as the main broad range tunable element determining the approximate absolute wavelength where the Matisse laser will operate To achieve single frequency operation two additional etalons are necessary as described below The combination of the Birefringent Filter and the Thick Piezo Etalon is in general not sufficient to guarantee single mode single frequency laser operation Therefore there is another frequency filter a solid state Fabry Perot etalon called the Thin Etalon TE Its position in relation to the laser beam can be adjusted with the help of a motor controlled mount It has an FSR of about 250 GHz for the standard etalon and a relatively small Finesse The TE is in a way adjusted that will give no direct reflections from the etalon s facettes into the laser beam paths to avoid complicated laser intensity dynamics For the TE it also true that one of its mode s frequency has to be the same as the laser resonator mode s frequency For this purpose the reflection from one facette is monitored and compared to the total laser intensity A control loop will adjust the TE position so that the ratio of these two signals is kept constant Single F requency Tunable Laser Physics 35 Piezo Etalon Description Figure 9 Front view
58. configuration file making it possible to calculate the frequency noise in the the Ref Cell Frequency Noise display see page 94 Also the setpoint of the Fast Piezo control loop see page 90 will be set to the displayed FPZ Setpoint value The value is calculated to be the amplitude value at the Full Width At Half Maximum points of the measured transmission spectrum Scan Conversion Factor tab Calculate Conv will perform the calculation of the Conversion Factor MHz full nominal scan range of 1 utilizing the Free Spectral Range MHZ information for the RefCell the Number of FSR and the Scan Range Set Conv stores the calculated conversion factor into the Matisse Commander s configuration file to be used by the Scan Setup dialog see page 106 X Stabilization Matisse Commander 98 only available for Matisse TX DX and TX DX light The Matisse laser frequency can be stabilized by locking the laser frequency to an external reference resonator using the Pound Drever Hall control scheme Fast perturbations that might destroy this lock are counteracted by an intra cavity electro optical modulator EOM Slower perturbations are cancelled by an actively controlled laser cavity mirror mounted on a fast piezo actuator FPZ An actively controlled slow piezo acting on another laser mirror ensures that the FPZ will always have its full dynamical range to react on perturbations How to lock the Laser optimize the mode matching of
59. connector that connects to the piezoelectric actor Vertical Etalon Alignment This differential micrometer screw controls the vertical alignment of the two prisms that form the etalon to each other Horizontal Etalon Alignment This differential micrometer screw controls the horizontal alignment of the two prisms that form the etalon to each other Prism The etalon is formed by two prisms The resonator beam enters and exits under Brewster s angle Piezo Etalon Dither Figure 11 Piezo etalon principle Etalon aligned Single F requency Tunable Laser Physics 37 Prism moved Fixed Prism by Piezo Beam exit and entrance under Brewster s angle Piezo Element Surfaces forming the Etalon Apart from further narrowing down the frequency range of possible laser modes the piezo etalon has also to ensure that one of its mode s frequency coincides with the resonator mode s frequency of the laser This is done by modulating the distance between the prisms with the help of the piezo actuator so that the frequency spectrum of the etalon is slightly modulated This results into a small intensity variation that is monitored and used as the input for a control loop that keeps the center frequency of the piezo etalon mode at the frequency of the laser resonator mode The control loop principle is shown in the following figure to cavity mode Etalon out of alignment Cavity Mode Cavity Mode Figure 12 PZETL Phase Locked
60. cy Scanning osse petet i re A iore t rise suede eere pst respi PE und 61 Saiid Bona a MR 62 Shut Down MM 62 Matisse Commander 63 InstalldtOn 5 oeste ott t ee cic Mei ee eee a tele Hueso edd 63 Version Changes a toe e eee erattu dee inde t ute Meet Sebi e eet epe Da e 63 Matisse Commander 1 6 eere n ener enne nnne ennt 63 Matisse Commander 1 8 sse ener enne nnne nter enne 64 General 527 eo dn hatten bas t cito pott sd tm dis bap eas 64 Slant Up EE 65 Ertot Dialog 22 2 s sete dea yts east ete iet aio drm d er de quete i een 66 Key N yvigationi s esta tats looted etes eet aoc dt ep 66 Wavemeter SupporL 4 lett eerte TETA reget D uc E edd ed reo ES 67 Firmware Upd te ee eese eee eter ede eei ee Pte e Riedel 67 Main Window ssec e e te tede eee e e eee ie dee eee feed a 68 Matisse Tools and Options ete eere oett ere etd te iei e i i 69 Device Configuration nete e He ee tede te e a deese eire 69 Advanced Options amp Tools esses eene nennen nnne ree enne enne 71 Control Switch Off Level teen tide tete e ete ste eee been d 74 POW UICC o eode e aee tege ee e oie ee ts 75 Motor Status 2 avete ede aite eee o e Oe res 75 Display Options cete ee e E dei eie eite ed Pete eed 76 Birefringent Filter cc cv iecit eei tee e eee eie rete e ee eee dR 76 Goto Birefringent Filter Position sssssssssessesseeeeeeenenener ener nere nennen nne 76 Birefringent Filter Scan ste
61. dye nozzle is centred with respect to the nozzle If not slightly move the dye drain which should be screwed down to the optical table to a different position In order to avoid the transmission of vibrations to the laser base plate the dye catching tube is not screwed to the laser It is just squeezed in its holder by some foam Therefore moving the dye drain slightly will allow to re centre the catching tube with respect to the nozzle 6 Set the spray guard back to the lower position see Figure below Figure 19 View of the spray guard in its lower position to avoid dye spray during the start up procedure of the jet Figure 20 View of the Matisse dye circulator The dye jet pressure might be varied by adjusting the needle valve 9 Basic Matisse Operation 49 Spray guard Mixing screw On the dye circulator make sure that the dye by pass is completely open The by pass is open if the needle valve shown on the next figure is turned counter clockwise as far as possible In this case when switching on the dye pump the main fraction of the dye will follow the by pass and no pressure will build up in the circulator system Pressure gauge Needle valve 10 Switch on the dye pump The cooling loop in your dye reservoir 11 should be connected in series to the chiller of the pump laser and thus already be operational If you are using an external cooling system then check that this system is operational
62. e grey plastic tube in your laser service box that should be installed between pump and Matisse laser to minimize perturbations caused by air flows Matisse Installation 119 3 Position the Matisse on your optical table so that the pump beam will pass through the center of the entrance opening Align the long side of the laser base plate so that it 1s parallel to the pump beam direction The pump beam will hit the first pump mirror PM1 rather on its edge that in its center Figure 77 Pin Holes Matisse Installation 120 4 For Matisse operation the pump beam path as well as the ring cavity beam path have to run at a height of 60 mm above the baseplate This height is marked by the center of the beam overlap tool see Fig 73 below if it is placed on the baseplate To determine whether the Matisse height is set correctly set your pump laser to the lowest possible output level Right after the Matisse pump beam input further attenuate the beam to avoid damage to the beam overlap tool This may be done using the mount from the color filter see figure below and mounting one of the spare neutral density filters from the service box instead Put the beam overlap tool into the attenuated beam and check whether it has got the correct height If the Matisse height needs to be adapted loosen the counter nuts on the Matisse feet wrench size 17 mm and the adjust the height by turning the nuts near the bottom of the feet wrench size 10
63. e next morning at the same wavelength CW lasers in general are temperature sensitive Therefore if the air conditioning in your laboratory is not running continuously take care to switch on the air conditioning and wait for thermal equilibrium before switching on your laser The best results will be obtained if your air conditioning is continuously running with temperature variations of no more than 1 K Start Up Matisse Ti Sa 1 Switch on your pump laser and allow for sufficient warm up time Please check your pump laser manual for details about the exact procedure and the necessary warm up time During this time take care that the pump beam is blocked before entering the Matisse laser If present use the internal shutter of your pump laser or any other suitable external beam dump 2 In the case of a Matisse TX first switch on the XBox Controller Switch on the Matisse electronics box and start up the Matisse Commander program 3 Place a power meter or any other suitable beam dump at the Matisse output port 4 Open the pump laser shutter or remove the external beam dump and apply pump power to the Matisse 5 Increase the pump power until the Matisse laser threshold is reached The energy level necessary for first laser operation depends on the mirror set and the current wavelength As a rough indication if pumped with a 532 nm beam and used at around 780 nm the Matisse should start lasing at about 2 5 3 W input pow
64. e Scan Piezo Voltage shown With the Direction indicator control the scan direction up or down can be quickly toggled For Matisse models TS or higher the main window contains also the Stabilization indicator control display with which you can turn on or off the locking of the laser to the reference cavity For this control loop the voltage applied to the slow piezo given by the Slow Piezo Voltage indicator control is of importance It should not exceed critical values if the slider is at the limits of the control use the slider to reset the value The Laser Locked indicator control indicates if the locking state is reached and maintained Clicking on it will toggle the Stabilization state Matisse Commander 69 Matisse Tools and Options Device Configuration Figure 33 Device Configuration Menu Matisse Commander 1 2 S N 99 99 99 Birefringent Thin Etalon Piezo Etalon Scan Help Configuration Administration Advanced Options amp Tools gt Set Active as Default Conf Set Control Switch Off Level Save Active Powermeter Load Configuration from File Motor Status Save Configuration to File Display Options Exit Ctrl x 0 70 A device configuration comprises the various parameters for the control loops the Birefringent Filter calibration parameters the scan setup the switch off level etc that are stored on the Matisse DSP controller board Two different kinds of configurations are avail
65. e X also the XBox controller Shut Down Matisse D on Oo OC Switch off the pump laser Open the Matisse top cover Loosen the fixing screw of the spray guard and move the guard to its lowest position The dye jet should be completely hidden inside the spray guard Open the needle valve on the dye circulator The dye will no longer flow to the sapphire nozzle but follow the bye pass Decrease the pressure until the dye jet starts to contract itself to a V shape form The indicated pressure is not 0 Switch off the dye circulator Close the laser cover Exit the Matisse Commander Switch off the Matisse electronics box and in the case of a Matisse X also the XBox controller 63 CHAPTER 7 Matisse Commander Installation The Matisse Commander program runs on Windows 2000 Windows XP and Windows Vista 32 and 64 bit versions Installing the program requires Administrator privileges A USB port is needed to connect the laser to the PC First install the software by executing setup exe in the Matisse Commander Installer subdirectory then connect the laser to the computer Windows should detect the new device and ask for a driver Let Windows execute an automatic search The Matisse Commander is based on LabVIEW 8 6 for device communications National Instruments VISA software is used Corresponding required software LabVIEW runtime 8 6 VISA runtime 4 3 or higher etc will be installed or updated during the Matisse
66. e transmission spectrum of the Reference Cell that should have 2 or more peaks separated from their neighbor peaks by the Free Spectral Range FSR that can be used to calculate a scan range frequency factor for the current scan device For the scan to be successful the positions of the Thick and Thin Etalon have to be optimized and the corresponding control loops have to be active beforehand In the case of the RefCell as scan device the RefCell control loops will be switched off automatically After closing the dialog the original control loops status will be restored Analyze will call up the RefCell Spectrum Analysis dialog see page 96 that will calculate the above mentioned conversion factor as well as the Finesse of the Ref Cell cavity and other properties that will be needed for the Ref Cell Frequency Noise display see page 94 For the analysis to be successful the spectrum has to contain at least two peaks Figure 59 Scan Device Calibration Measurement dialog Analysis Matisse Commander 96 RefCell Spectrum Analysis Only available for Matisse TS DS I RefCell Spectrum Analysis Peak Table Position Amplitude FWHM 0 202499 0 303113 0 000281 0 207499 0 308122 0 000277 Peak Width 130 4 Range MHz iv lt 600 Free Spectral Airy Fit Scan Conversion Factor Fit RefCell Finesse Amplitude Maximum Intensity tJ 17 8 0 494199 0 3
67. eface 9 1 x Mains cable 1 x USB cable 4 x Laser fixing clamps 1 x Filter for purging the laser head 1 x Beam tube to be installed in between pump laser and Matisse 2 x Laser warning signs Service Accessories 1 x Set of metric Allen head keys 1 5 2 2 5 3 4 5 mm 1 x Set of neutral density filters for Matisse laser head diodes 1 x Tool 1 Pump mirror pinholes 1 x Tool 2 Lyot filter dummy 1 x Tool 3 Thick etalon dummy 1 x Tool 4 Beam overlap tool 1 x Tool 5 Pump beam filter Ti Sa laser only 1 x Tool 6 Mirror mount ring Spare parts 1 x Set of spare O rings 25 mm x 1 5 mm and 25 1 mm x 1 6 mm for mounting of mirrors Additionally depending on the configuration of your laser the service box may contain further items which are indicated in a list included in the box Matisse Preface 10 CE Declaration of Conformity Manufacturer Sirah Laser und Plasmatechnik GmbH Ludwig Erhard Str 10 41564 Kaarst Germany Phone 49 2131 660 651 Fax 49 2131 668 095 Product Name Matisse Product Types TR DR TS DS TX DX Directive Council Directive 73 23 EEC Low Voltage Council Directive 89 336 EEC Apendix I Electromagnetic Compatibility Applicable Standards EN 61010 1 2004 Safety requirements for electrical equipment control and laboratory use EN 60825 1 2001 Safety of laser products Part 1 Equipment classification requirements and user s guide EN 61326 1
68. electric actuator to minimize the acoustic transmission of noise to support a better thermalization Do not open the venting valve 30 CHAPTER 4 Single Frequency Tunable Laser Physics This chapter intends to give a concise and simple introduction into the physics and technologies used to operate the tunable single mode continuous wave Matisse laser Single F requency Tunable Laser Physics 31 Principle Laser Set up As the acronym L ight A mplification by S timulated E mission of R adiation indicates one crucial part of a laser is an amplifying medium This gain medium has in general to be exited pumped by a adequate sources to act as an amplifier for electromagnetic radiation The spectral bandwidth of a laser medium can be relatively small e g just one atomic resonance or very large covering a wavelength range of under 700 nm to over 1000 nm in the case of Titanium doped Sapphire T1 Sa or a range of some 10 nm for various dyes The second prerequisite for a laser 1s an optical resonator being in a simple case a pair of parallel spherical mirrors which acts as a feedback loop for the amplifier medium This system of an amplifier with feedback can produce self exited electromagnetic fields in the form of laser beams which have well known special properties First they have a very high spatial coherence i e they have a very small spotsize when focused they are the best practical approximation to an
69. ensity J 0 221191 0 17 1 1 D 1 1 1 1 1 1 u 783 800 820 840 860 880 900 920 940 960 982 Maximum Deviation MHz RMS Deviation MHz FPZ SetPoint 0 094195 0 0325394 0 0199737 eux N um c S5 2 E gt o e gt v bs o Pj Cr v D w S D 1 This dialog shows the relative Frequency Deviation from the current lock frequency of the Reference Cell calculated with the help of the PDH error function for a resonator with a free spectral range of FSR RefCell MHz and a finesse of Finesse These values have to be adapted to your Reference Cell for an X Matisse model the FSR has normally a value of 1320 GHz You also need the PDH Error Signal Maximum Intensity and PDH Error Signal Maximum Intensity values that can be determined with the PDH Error Signal Measurement see page 105 dialog The Maximum Deviation MHz and the RMS Deviation MHz gives you some statistical properties for the displayed sample series Matisse Commander 105 Pound Drever Hall Error Signal Measurement Figure 64 PDH Error Signal Measurement Only available for Matisse TX DX and TX DX light Pound Drever Hall Error Function Measurement E iol xl 0 14 j TERES 0 0 12 Reference Cell Piezo 0 1 0 06 m 0 04 5 A i 0 02 5 04 Re fa PE Scan Range a 0 04 K ZU m 0 05 zj 0 02 0 08 Scan Increment Adr AEs 2 12 J 9 147 1 1 1 1 1 D i 0 243 0 24325 0 2435 0 24375 0 244 0 24425 0 2
70. er 6 Slowly increase the pump power up to 5 W At this pump energy most Matisse laser configurations should start lasing However for wavelengths at the edge of the tuning range of the used mirror set or at the limit wavelengths of the Ti Sa crystal itself even higher pump power might be necessary Your Matisse laser should now operate In this case please refer to the next Sections for a quick optimization of the Matisse output power If in contrast your Matisse laser is not yet operating carefully check the entire pump beam path Basic Matisse Operation 48 Start Up Matisse D Figure 18 View of the dye jet nozzle and the dye catching tube The spray guard is fixed at its upper position 1 Switch on your pump laser and allow for sufficient warm up time Please check your pump laser manual for details about the exact procedure and the necessary warm up time During this time take care that the pump beam is blocked before entering the Matisse laser If present use the internal shutter of your pump laser or any other suitable external beam dump In the case of a Matisse DX first switch on the XBox Controller Switch on the Matisse electronics box and start up the Matisse Commander program Open the Matisse top cover Place a power meter or any other suitable beam dump at the Matisse output port Move the spray guard to its upper position see Figure below Verify that the dye catching tube situated underneath the
71. er Date of installation gt Problem Please give as much details as possible Mail to Email to Or fax to Sirah Laser und Plasmatechnik GmbH Ludwig Erhard Str 10 10 D 41564 Kaarst Germany info sirah com Sirah Laser und Plasmatechnik GmbH Fax 49 2131 66 80 95 Index A About 113 Advanced Options amp Tools 71 B Basic Matisse Operation 47 Birefringent Filter 34 76 Birefringent Filter Calibration Table 79 Birefr Filter Scan 80 Birefr Filter Scan Options 80 Birefringent Filter Scan 77 Birefringent Filter Scan Options 78 C Cavity Mirror Optimization 52 CE Declaration of Conformity 10 CE Electrical Equipment Requirements 6 Control Loop Live View 73 Control Loop Live View Options 74 Control Switch Off Level 74 Controls Box Front and Rear Panel Features 21 ControlScan Setup 109 ControlScan Values Measurement 110 Customer Service 132 D Dangers Caused by Laser Dyes and Solvents 13 Device Configuration 69 Device Configuration Administration 70 Device Hardware Configuration 74 Display Options 76 DSP Input Charcteristics 127 E Environmental Specifications 6 Error Dialog 66 F Fast Piezo Amplifier Board Input Characteristics 128 Fast Piezo Control Setup 90 Firmware Update 67 Focused Back Reflection Danger 14 137 Frequency Drift Compensation 45 Frequency Scanning 61 Frequency Setting
72. f the mirror mount Squeezing the mirrors in the rings by using o rings allows to unscrew the rings together with the mirrors from the mounts without the risk of mirrors dropping on the floor as shown on the Figure below Figure 74 Matisse mirror squeezed in a metal ring The mirror will not fall even when the ring is turned upside down Figure 75 Matisse mirror and mirror mount ring with the two o rings in place Figure 76 Use mirror mount ring to press the mirror in the metal ring Maintenance 116 To remove the mirror from the mount just gently pull the mirror with your fingers Two o rings are used in the mirror mounts When mounting the new mirror in the ring make sure that both of these o rings are present as shown on the figure below One thick o ring covers the bottom of the mirror s metal ring Another thinner o ring is used for squeezing This one needs to be wrapped around the mirror as shown in the figure Then place the mirror on the ring and squeezed it in the ring by using tool 6 see figure below Apply pressure on mirror mount ring Tool 6 CHAPTER 9 117 Matisse Installation The first installation of your Matisse is done by a Sirah or other qualified service engineers This includes the mechanical set up as well as the adjustment of the pump optics and the Matisse laser beam path Therefore the installation procedure described in the present chapter is not intended for
73. f this range is too small the laser lock becomes unstable This trade off situation finally limits the achievable laser bandwidth with the side of fringe stabilization scheme Detailed instructions for the various control loop settings can be found in the S Stabilization see page 88 section of the Matisse Commander chapter Frequency Stabilization 42 Pound Drever Hall frequency stabilization To DSP Figure 15 Matisse TX Setup For the PDH stabilization scheme there are additional elements in the optical path leading to the reference resonator in comparison to the Matisse S setup The schematic setup is shown in the following figure Laser Head Reference Cell Transmission Fast Amplifier Variable Attenuator High Pass Slow Amplifier Pound Drever Hall Unit First of all there are two lenses acting as a telescope to mode match the Matisse laser beam to the fundamental mode of the non confocal reference resonator Then follows an Electro optical Modulator EOM acting as a phase modulator which is modulated sinusoidally with a frequency of v With this modulation the frequency spectrum of the laser beam after the EOM has now essentially three components Vo Va Vo Vo Vmod Assuming that the reference cell is about resonant with the fundamental laser frequency v and its finesse is so high that the frequencies v v and Vo Vma are well outside of the resonator linewidth only the laser radiation par
74. fset Jo 177628 0 8 1 Li 1 Li n 19504 19850 19900 19950 20003 t Maximum Deviation MHz RMS Deviation MHz FPZ SetPoint Figure 57 RefCell Frequency Noise display This dialog shows the relative Frequency Deviation from the current lock frequency of the Reference Cell calculated with the help of the inverse Airy function for a resonator with a free spectral range of FSR RefCell MHz and a finesse of Finesse These values have to be adapted to your Reference Cell for an S Matisse model the FSR has normally a value of 600 GHz You also need the RefCell Spectrum Peak Intensity and RefCell Spectrum Intensity Offset values that can be determined with the RefCell Properties Measurement see page 95 dialog The Maximum Deviation MHz and the RMS Deviation MHz gives you some statistical properties for the displayed sample series Matisse Commander 95 RefCell Properties Measurement Figure 58 Scan Device Calibration Measurement dialog Only meaningful for Matisse TS DS Scan Device Calibration Measurement 2 iol xl Scan Device Reference Cell Piezo 5 E Scan Range La E 110 02 ivi y 5 a Scan Increment 2E 5 y Scan Position 2 i Close Measure will perform a sampled scan with a range of Scan Range and an increment of Scan Increment with the current Scan Device either RefCell or Slow Piezo while measuring the transmitted intensity of the Reference Cell The result will be th
75. gle step up to 4 bar Wait for 5 minutes increase the pressure to 6 bar and wait another 5 minutes Depending on the type of dye solvent you use this pressure may already be sufficient to operate your laser Furthermore laser operation is usually not limited to a single pressure value but is rather possible in a certain pressure range of up to some bar If you start with a new solvent and or dye you should carry out a series of tests of laser operation at different pressures to find optimal conditions and parameters The aim is to obtain high output power which is as stable as possible 1 e there should be no flickering visible within the output beam Note that changing the pressure during the adjustment can slightly alter the shape of the dye jet so you may also have to change the pumping position and or the location of the focus with the pumping mirror PM in order to regain optimal laser output If you increase the pressure continue in similar steps as before i e wait 5 minutes after each increase of up to 2 bar Do not increase the pressure in bigger steps than 2 bar at once and do not forget to watch the dye backflow 15 During the first minutes of operation characteristic noise from the nozzle indicates the presence of air bubbles in the dye If the increase in pressure is done slowly enough then the number and size of these bubbles will be at a minimum The bubbles will vanish with time When the final pressure is reached do not con
76. he laser power curve Set Thin Etalon Control Position Thin Etalon Reflex 7 Thin Etalon Scan Total Power a 0 8 0 5 Set Motor Position 1 19130 y Thin Etalon Reflex 4 aM0d 301 Goto 0 07 1 1 1 1 1 1 170 3 18000 18200 18400 18600 18800 19000 19200 19400 19600 19800 20000 Thin Etalon motor position Figure 25 Drag and drop the red cursor on the left hand side of a minimum of the blue curve indicating the power reflected from the thin etalon Figure 26 Main Window Basic Matisse Operation 57 When the cursor is properly set to a position corresponding to a reflection minimum leave the dialog window by hitting the respective button In the Matisse Commander main window click on the TE Control indicator The dark green indicator will switch to bright green as shown below indicating that the electronics is now continuously controlling the etalon position in order to minimize the reflection and maximize the laser power The blue bar underneath the TE Control lamp labelled TE Signal monitors the thin etalon error signal allowing for a rapid check of proper etalon operation by just a glimpse Matisse Commander 1 8 S N 99 99 99 DER Matisse Birefringent Filter Thin Etalon Piezo Etalon 5 Stabilization Scan Help Current Position 800 0 nm Laser Locked Laser Power 0 827 0 704 0 604 3 oso m a E pay c E bat G a o o w 2 o
77. he two spots at both positions can be achieved Do a check by putting the beam overlap tool between the beam displacement rhombus PS and FM1 If the adjustment is good the two spots will also be superimposed here Remove the two pin holes Make sure that there is no obvious dust on PM If there is any dust refer to the chapter Handling of Optical Components for cleaning Then increase the pump power to at least 5 W If the laser is not already lasing observe the fluorescence shapes in the laser output Carefully pull at the mirror knobs at the laser output side M1 and M3 to see if there is a short laser flash and adjust the respective mirrors to reach lasing Matisse Installation 125 Optical Alignment Procedure for the Matisse S Reference Cell Figure 80 RefCell S Scheme The schematical setup of the confocal reference cell and beam paths are shown in the figure below For a basic adjustment of the reference cell you should first make sure that the Matisse laser beam passes approximately through the center of the entrance opening beam splitter BS and the exit opening Confocal Resonator Mirror 1 PD Matisse laser beam Beam Splitter Align the partial beam from BS with the help of mirrors BS and MI Mirror 1 in that way that it will pass approximately through the center of the reference cavity Keep in mind that you have actually two partial beams one from the front side of BS and one from the back side Block the
78. ics The external input of the Piezo Amplifier Board for the Fast Piezo has the following electrical characteristics Parameter Value Connector Type SMA jack connector MIL C 39012 Voltage Range 0 0 4 0 Volts Input Impedance gt 1 MQ 129 CHAPTER 11 Frequently Asked Questions and Troubleshooting I cannot get the expected or usual power output from the laser apply the procedures given in the Power Optimization see page 51 section check the laser optics for damages or dust particles Observe the information given in the Maintenance chapter see page 114 check if the clockwise running mode of the ring resonator is exited see question below check if the laser beam shows spatial instabilities see question below I experience strong power fluctuations a big drop in power output more than 30 and I can see a second laser spot in the laser on its housing about 4 cm right to the normal laser beam exit In this case the clockwise running mode of the ring resonator is exited This can happen if the two surfaces forming the Piezo Etalon are adjusted perpendicularly to the laser beam so that reflected parts of the beam fully interact with the laser gain medium This may lead to complex intensity and polarization dynamics of the laser making the optical diode inoperable Therefore the orientation of the Piezo Etalon relative to the laser beam can be adjusted For this purpose there are two screws with bla
79. idebands are then no longer equidistant in relation to the resonator field frequency to be precise you have to look at the optical phases resulting in non zero terms for the PDH signal The Pound Drever Hall method actually detects optical phase shifts rather than frequency shifts making it very sensitive The PDH stabilization method is insensitive to laser intensity noise The catching range for this method is given by the modulation frequency Vma Together this makes the Pound Drever Hall stabilization a highly sophisticated tool for locking schemes In the Matisse TX DX light versions the PDH error signal 1s used as the error signal for the Fast Piezo control loop achieving a significant improvement in the laser bandwidth in comparison to Matisse S models In the full Matisse TX DX versions an EOM is added to the laser resonator that will also use this signal after adequate signal conditioning as the error signal for its control loop Because the EOM has a much larger control bandwidth a further significant improvement in the laser bandwidth can be seen Detailed instructions for the various control loop settings can be found in the X Stabilization see page 98 section of the Matisse Commander chapter Frequency Stabilization 45 Frequency Drift Compensation Experiment Figure 17 Possible Matisse Setup using an atomic resonance to compensate frequency drifts Gas Cell J Matisse Commander Photodetectors T
80. iezo r 0 Figure 68 ControlScan Setup dialog The ControlScan parameters are factors that are multiplied by the change of the nominal scan piezo voltage change and added to the position of the corresponding elements Birefringent Filter Thin Etalon Thick Piezo Etalon and the Slow Piezo the latter element is only of importance for Matisse models TS DS or higher These parameters are essential for fast scans scan speed of 1 GHz s The position changes will be executed even if the control loops for these elements are not active The values determined here correspond to a change of the scan piezo by the full nominal range of 1 Calc BiFi Factor will calculate the corresponding factor using information from the calibration function for the Birefringent Filter see Calibration Table see page 79 and the conversion factor for the current scan device see Scan Device Configuration see page 108 There are different sets of ControlScan parameters depending on the selection of the Scan Device see Scan Device Configuration see page 108 Pressing OK will set these parameters for the active configuration To make changes permanent you have to save the active configuration see Device Configuration see page 69 Matisse Commander 110 ControlScan Values Measurement Figure 69 ControlScan Values Measurement ControlScan Values Measurement m Scan Device Scan Range Slow Piezo Measure 10 1 Piezo Etalon Scan Speed
81. in the laser operation area Eye s pupils remain constricted and thus are less sensitive to scattered laser light Mark the laser operation area by prominent warning signs Safety P recautions 13 Dangers Caused by Laser Dyes and Solvents The physical chemical and toxicological properties of organic dyes are not well characterized Just as the solvents they should be treated as poisonous Thus an extreme caution is required in handling these substances During the work with laser dyes eating and drinking are strictly forbidden inside the laboratory Always wear protective gloves and a protective mask when weighing out the laser dye Following these measures an inadvertent ingestion of any dye can be excluded A more likely hazard is the potential for absorption of solvent or dye solution through the skin Even if the solvent itself is not extremely dangerous some solvents can penetrate the skin easily and carry the toxic dyes into the body This is especially true for solvents as e g benzyl alcohol DMSO dimethylsulfoxide p dioxane and methanol Therefore we highly recommend always to wear protective gloves laboratory overalls and a protective mask when handling laser dyes and solvents Your chemical supplier can give you further information concerning storage handling and waste management of laser dyes and solvents Almost all solvents are highly inflammable and volatile a fact that should always be remembered when handling the
82. ined direction M3 Tweeter Mirror M3 This mirror is mounted on a piezoelectric actor Changing the voltage applied to the actor will change the position of the mirror and ultimately the optical path length of the cavity The effect is used for mid bandwidth correction of the Matisse s emission wavelength Note The Matisse DR has no active control of the emission wavelength in this case the mirror is fixed directly to the mount TGG TGG Plate The TGG plate is made from Terbium Gallium Garnet and acts as a Faraday rotator when exposed to a strong magnetic field The combination of M2 and the TGG plate forms an optical diode that supports laser activity in a defined direction Note The magnetic field is generated by two powerful permanent magnets Be careful when using tools close to the device Piezo E Piezo Etalon The piezo etalon selects a single longitudinal mode from the spectral range that is determined by the configuration of output coupler birefringence filter and thin etalon To maintain the exact match of etalon and longitudinal mode the spacing of the etalon is dithered by an piezoelectric actor and a lock in scheme is used to control the etalon spacing Thin E Thin Etalon The thin etalon is used as a bandpass filter To provide tunability the tin etalon is attached to a motor driven mount A step motor controls the horizontal tilt angle of the etalon EOM Electro Optical Modulator The non resonant intra cavity electro opti
83. irectly You can move a motor to an Absolute Position by pressing Goto Keys F5 to F8 Big Increment down Small Increment down Small Increment up Big Increment up will change the motor position relative to the current one The increments can be set in the Motor Control Options dialog see page 111 press the Options button The Home button will set the motor to its home zero position defined by a hardware switch Motor Control Options Motor Steps Birefringence Filter Motor Control Small Increment 10 Big Increment 100 d Figure 71 Motor Control Options dialog Big Increment and Small Increment sets the steps a motor will be moved relative to its current position in the Motor Control dialog see page 111 Matisse Commander 112 Wavemeter only available with Wavemeter Support see page 67 If the Use Wavemeter menu entry is ticked the Current Position display in the main Matisse Commander window will show the wavemeter readout Scan Device Calibration with Wavemeter only available with Wavemeter Support see page 67 Scan Device Calibration with Wavemeter iol xl 5 077740E 3 scan ee mmm Reference Cell Piezo 5 077730E48 l 5 077710E 8 uw T 5 077700E 8 5 077690E 8 Scan Range 9 5 077680E48 Jfo os gs v d 5 077670E48 San Speed 5 077660E48 Jj 10 001 5 077650E48 5 077640E 8 Set 5 077630E 8 7 i i i i I 1 C
84. ji Clear OK 1 1068 This dialog lets you view the internal variables used by the various control loops Process Controller and Setpoint value and can be used to optimize the control loop parameters It is a non modal window i e it runs in parallel to the main program From the Protocol control you can choose which control loop none Thin Etalon Thick Piezo Etalon Slow Piezo Fast Piezo is to be logged The logging process uses a 256 value ring buffer to record the data If the selected control loop is not active the ring buffer may hold random data There are two Sample Modes available Continuous or Snapshot Continuous will give a steady data stream Because of the different time scales the control loops are working on you may have a real live view for the slower loops or just a sampling view for the faster ones An indicator which kind of behavior you experience is the Ordinal Number If it stays the same all the time or increase only slightly over time the current control loop values are read out if it increases rapidly you only have a time sampled view of the control loop The debug view behavior can be influenced by changing the Period time interval with which the logging buffer is read out Options will open the Control Loop Live View Options dialog see page 74 where the default values for the period times can be changed Choosing too small a period value may lead to communication errors due to the parallel acce
85. le material inadvertently used as a beam stop poses a fire hazard Thus working with such laser systems utmost precautions have to be taken Pay special attention to all advice given by the manufacturer of your pump laser In the following some general safety rules for the usage of lasers are given These recommendations are by no means complete rather they constitute the bare minimum of precautionary measures necessary to avoid laser induced dangers and damages Each person working with the laser or present in its operating room should wear laser radiation safety goggles Note that the safety goggles should give protection against the radiation of all lasers used in the operating room which are in each case the pump and the Matisse laser but also radiation generated by up or down conversion of the laser light Keep the laser closed This means not only to keep the housing of the laser closed during laser operation but also to enclose the emerging laser beam e g in tubes where feasible and to terminate the beam with a suitable beam stop Keep the internal protection sheets and beam stops in place Under no circumstances look into the laser beam For security reasons even when the laser is switched off never look backwards in direction of the laser beam Avoid wearing reflective jewellery while using the laser Especially watches are excellent mirrors for laser radiation Do not risk to reflect the beam into your eyes by them
86. mit 10 1 J Scan Lower Limit J 0 085 Oversampling J128 2 a EI E a ees Sampling Mode Jj Maximum Close You may further adjust the laser beam to optimize the spectral output of the reference cavity You can achieve a situation where every other transmission peak will have a strongly reduced peak value In this case the Gaussian laser mode is matched to the Gaussian reference resonator mode so that no higher order modes are excited This situation is highly sensitive to deadjustment and may be difficult to find It is not necessary to reach this situation to obtain optimal laser locking to the reference cell Choose a set of neutral glass filters so that you have a good signal to noise ratio for the waveform but are still below the saturation threshold 127 CHAPTER 10 Matisse Electronics DSP Input Charcteristics The external input of the DSP has the following electrical characteristics Parameter Value Connector Type SMA jack connector MIL C 39012 Voltage Range 5 0 5 0 Volts Input Impedance 3 4 KQ Piezo Amplifier Board Input Characteristics The external input of the Piezo Amplifier Boards for the Scan Device or the Thick Piezo Etalon has the following electrical characteristics Parameter Value Connector Type SMA jack connector MIL C 39012 Voltage Range 0 0 3 0 Volts Input Impedance gt 1 MQ Matisse Electronics 128 Fast Piezo Amplifier Board Input Characterist
87. mm One revolution corresponds to 2 mm of vertical movement Make sure you turn each of the nuts by the same amount to avoid instabilities and tilting of the Matisse housing Finally gently tighten the counter nuts without holding the nuts at the bottom of the feet In the service box you will find two pin holes that can be set on the two half inch mirrors directly located at the Ti Sa crystal FM1 and FM2 Set the pin holes on the mirror side facing the crystal Adjust the pump beam with the help of the pair of pump mirrors PM1 and PM2 so that it passes through the centers of the two pin holes Make sure that the pump beam has got the correct polarization p polarized Loosen the plastic screw at the half wave plate on the Matisse input and rotate it so that the power of the pump beam reflex from the Ti Sa crystal on the little beam blocking sheet is minimized Figure 78 Color Filter Figure 79 Overlap Tool Beam Matisse Installation 121 7 In the service box you will find a mounted green filter red glass plate Put it into the laser between the crystal mount and the second folding mirror FM2 so that residual pump beam radiation circulating through the resonator is filtered out Align it perpendicularly so that the back reflected green spot hits the pinhole center on FM2 Increase pump power to about 1 W An IR viewer will help you in observing the fluorescence spots Note that the spots may not have the same
88. nction are listed below Indoor use Altitude maximum of 3000 m Temperature 15 C to 35 C Humidity 30 to 60 non condensing conditions Insulation category 1 Pollution degree 2 Standard Units Matisse Preface 7 The following units abbreviation and prefixes are used in Sirah Manuals Quantity mass length time frequency force energy power electric current electric charge electric potential resistance temperature pressure Prefixes 10 12 tera giga 10 9 zZz Q mega 10 6 kilo 10 3 Unit kilogram meter second Hertz Hewton Joule Watt Ampere Coulomb Volt Ohm degree Celsius Pascal deci 10 1 d centi 10 2 c milli 10 3 m micro 10 6 u Abbreviation kg m o 0 z Pa nano 10 9 pico 10 12 femto 10 15 atto 10 18 Matisse Preface 8 Unpacking and Inspection Your Sirah laser system was assembled checked and packed with great care It was shipped in a container specially designed for this purpose Upon receipt of your system inspect the outside of the shipping container If there is any major damage insist that a representative of the carrier being present when you unpack the contents All Sirah laser containers are equipped with shock and tilt indicators Carefully inspect these indicators If any of them is actuated insist that a written confirmation is done on the shipping papers signed by the carrier If the tra
89. nder 87 The graph shows the AC part of the total laser power The curve should be stationary when the Piezo Etalon control loop is on and should have a sine like w shaped harmonic form starting with a maximum S Stabilization Matisse Commander 88 only available for Matisse TS DS The Matisse laser frequency can be stabilized by locking the frequency to a mode of an external reference resonator using the side of fringe locking technique Pertubations that might destroy this lock are counteracted by an actively controlled laser cavity mirror mounted on a fast piezo actuator FPZ An actively controlled slow piezo SPZ acting on another laser mirror ensures that the FPZ will always have its full dynamical range to react on pertubations How to lock the Laser open the RefCell Waveform see page 93 display and set Scan Upper Limit to 0 1 Scan Lower Limit to 0 Oversampling to 128 and Sampling Mode to Average Optimize the adjustment of the laser beam into thee reference resonator The photo diode signal for the transmitted light has a nominal value range from about 0 2 to 0 4 The signal maximum value should be lower than 0 25 Adapt the filters accordingly open the Fast Piezo Control Setup see page 90 dialog set the Setpoint to a value about half of the maximum peak signal seen in the Waveform display make sure the slow piezo baseline is in the middle of its range activate the lock by clicking on the RefCell
90. ns The Laser Safety Chapter should be read by all persons working in the laboratory where laser radiation occurs even by those not directly involved in laser operation The next chapter contains a general Laser Description with some details about the optimum performance range of your Matisse The laser s Controls are described in the following chapter An concise introduction into Single Frequency Tunable Laser Physics and the techniques used for Frequency Stabilization follows The operation of your Matisse laser on a day to day basis is described in detail in the next chapter This chapter contains both basic operation hints necessary for your everyday work with the laser system as well as more detailed alignment and optimization procedures for all relevant components of your laser To keep the laser working at optimum performance is quite easy as long as you do not totally corrupt the laser optical set up Some effort has been undertaken to illustrate the different laser optimization possibilities as step by step procedures Please always read the whole section corresponding to your task before doing the first step The following chapter serves as a description and reference for the Matisse Commander computer program with which the Matisse laser is controlled Matisse Preface 5 The Maintenance chapter will deal with all relevant maintenance tasks necessary for a stable long term operation of your laser system If you have to m
91. nsmitted intensity of the reference constant The laser frequency is then locked to one of the reference resonator s modes To achieve this locking a second laser resonator mirror is mounted on a piezo actuator the Fast Piezo This Fast Piezo has to counteract relatively fast perturbations to reduce the effective laser bandwidth The former scan piezo mirror the Tuning Mirror in the Matisse TR DR now becomes a kind of auxiliary piezo the so called Slow Piezo It has two tasks to fulfill first in the not Icoked case it will scan the laser to a resonance of the reference resonator Second when locking is achieved it will keep the Fast Piezo at the center of its dynamics range and so cancelling out slow drifts of the laser in relation to the reference cell The schematic setup is shown in the following figure Tuning Titanium Sapphire Thick Etalon Unidirectional Fast Reference Mirror Crystal Piezo Driven Device Piezo Cavity Thin Etalon Birefringent Filter Output Motor Driven 3 Plates Motor Driven Coupler Laser Reference Cell Figure 13 Matisse TS Setup The reference cell in this case is a confocal resonator with a free spectral range of 600 MHz and a Finesse of about typically 15 to 20 The Airy Transmission spectrum is shown in the figure below normalized to 1 l ransmitted Intensity Figure 14 Airy Transmission Spectrum Frequency Stabilization 4l Airy Transmission signal for a resonator with FSR 600 MHz
92. nsport boxes are in good condition and none of the shock and tilt indicators is actuated then carefully unpack and inspect the laser system and all accessory parts Each system is accompanied by a packing slip listing all the parts shipped Verify that your system is complete and undamaged In case of any problems like damaged or missing parts please immediately notify the carrier and your Sirah sales or service representative Addresses may be found in the Customer Service Chapter Keep the shipping containers If you file a damage claim you may need them to demonstrate that damage occurred during transport If you want to move your laser to another laboratory building or if you need to return the system for service the specially designed container assures adequate protection System Components Service Box The following components comprise the Matisse laser system Matisse laser head Matisse electronics box Matisse service box Matisse dye circulator system only for dye laser version Further components may be supplied together with the laser system according to the packing list Each Matisse laser is delivered together with a service box containing some laser accessories and service tools for your everyday work with the laser as well as some spare parts The following items are included in your service box Installation Accessories 1 x Matisse Laser Manual 1 x Matisse Commander Installation CD ROM Matisse Pr
93. ntial requirement for optimal performance of your Matisse laser Hence you should routinely check and clean all its optical components Avoid to touch optical elements with your fingers The fat persistent at the fingers collects on the surfaces of the optical elements from which it can hardly be removed In particular visually non perceptible layers may remain that considerably increase the losses in your laser cavity thus reducing the laser output power or destroying the surface itself The first condition to keep the optics clean and make your laser work at highest power is to always keep your laser under a permanently operating flow box Additionally from time to time you should wipe the optical surfaces with a soft clean Q tip Only apply very gentle pressure in order not to scratch the surface with the dry cotton The advantage of dry cleaning is to avoid smears from residual cleaning liquids on the optics but once again dry cleaning supposes only very gentle pressure In the case of important dust on the optics you may clean them by using isopropanol spectranalyzed or equivalent grade e g spetranal and lens cleaning paper e g Kodak lens cleaning paper In this case if ever possible you should remove the optics from their mounts in order to have easy and full access to the surface A part of the lens cleaning paper is wetted with isopropanol and wiped over its surface with low pressure In the ideal case it 1s sufficient to d
94. of the piezo assembly etalon The piezo etalon is formed by two prisms with parallel base sides functioning as a Fabry Perot interferometer with an air gap One prism is mounted to an piezoelectric actuator to control the air gap thickness The free spectral range of the interferometer 1s about 20 GHz and a Finesse of about 3 The piezo etalon ensures that all except one longitudinal mode have so high losses that lasing is not possible Therefore the spacing of the etalon must be matched to an multiple of the favored longitudinal mode s wavelength Because of the tight spacing and in order to be able to perform a scan the spacing is actively controlled The control loop is based on a lock in technique and the etalon spacing is varied by a piezo drive Prism The etalon is formed by two prisms The resonator beam enters and exits under Brewster s angle 2 Horizontal Alignment This screw controls the horizontal tilt of the entire etalon assembly 3 Vertical Alignement This screw control the vertical tilt of the entire etalon assembly 4 Piezo Voltage SMA connector that connects to the piezoelectric actor Figure 10 Side view of the piezo assembly etalon Single F requency Tunable Laser Physics 36 Horizontal Alignment This screw controls the horizontal tilt of the entire etalon assembly Vertical Alignement This screw control the vertical tilt of the entire etalon assembly Piezo Voltage SMA
95. ol and pressing Goto Pressing Start will execute the scan that can be aborted by the Stop button Set will move the motor to the position the cursor in the graph points to Achieving maximal laser output requires the Birefringent Filter to be positioned optimal in relation to the thin and thick etalon After a scan you should see a curve for the thin etalon s reflex that looks like a step function Set the graph s cursor by dragging it with the left mouse button pressed about into the center of such a step so the position coincides with a local maximum of the total laser power and press Set If Set is not used the motor will stay in the scan s end position when you close the dialog Matisse Commander 78 Birefringent Filter Scan Options Birefringent Scan Options Ed Scan Range 3000 Scan Increment 150 These controls determine the Scan Range and Scan Increment of the Birefringent Filter Scan Figure 47 Birefringent Filter Scan Options dialog Matisse Commander 79 Birefringent Filter Calibration Table Figure 48 Birefringent Filter Calibration Table Editor gt Calibration Table D Projekte Progr m Ed Wavelength nm Motor Position amp Get MOTBI Pos 786 017049 95207 785 192399 97207 Delete 784 615674 99207 783 795573 101207 Sort 782 977952 103207 782 406844 105207 781 592091 107207 780 779089 109207 780 211279 111207 779 401189 113207 778 592892 115207 778 030611
96. omer Service Index Warranty essse Return of the Instrument for Repat esanean enne enne nennen nennen enne nnne Service Centres Problems and Solutions 114 114 115 117 117 118 118 118 122 125 127 127 127 128 129 132 132 134 136 137 CHAPTER 1 Matisse Preface Thank you for purchasing the Sirah Matisse laser system This manual was written to show you how to safely install operate maintain and service your laser system An attempt was made to describe the laser both accurately and completely However due to the continuous progress in technical development discrepancies between manual and delivered laser system may occur Before applying pump laser power to the laser system it is strongly recommended to read this manual thoroughly and to understand its content The first chapter deals with Laser Safety The Matisse laser in combination with a powerful pump laser is a class IV high power laser Its laser radiation represents a serious hazard for your personal health as it can permanently damage your eyes and skin Moreover inadequate operation of the laser system may damage other laboratory equipment e g by ignition of combustible substances or by laser sputtering of surfaces as well as the laser system itself e g by focused back reflections To minimize the risks connected to laser operation read this Chapter thoroughly and carefully follow the instructio
97. ommander configuration file Available Scans shows all stored scans Its default value is SDEVICE i e it shows the current scan setup in the Matisse DSP controller When you select a stored scan setup the scan data will be shown in the respective fields the current scan position will not change With Set this scan setup will be sent to the Matisse controller You can create new scans with New prompting you for a scan setup name do not use names starting with a sign Save and Delete will do the corresponding actions for the displayed scan setup except in the case of DEVICE Changing the controls values except Position has an immediate effect on an active scan Matisse Commander 108 Scan Device Configuration Scan Device Configuration Scan Device Reference Cell Piezo LI Conversion Factor 1 84348 41 MHz scan range of 1 Laser Position nm at 775 3555 Figure 67 Scan Device Configuration This dialog lets you select the Scan Device that is used during a scan Possible devices are Reference Cell Piezo Slow Piezo or No Device Slow Piezo means that the intra cavity piezo is scanned which will cause a direct change of the laser s frequency Matisse TR DR setup Reference Cell Piezo means shifting the transmission spectrum of the Reference Cell which will cause an indirect change of the laser s frequency via the locking of the laser to the cell For the scan to be effective in this ca
98. ongated because of the oblique angle under which it hits the housing When you use an infra red viewer pay attention to look at the Matisse laser spot and not at the pump laser spot that will be close by Dye Matisse Look at the spot coming from mirror FM 1 hitting the laser housing between pump beam entrance and TM mirror mount Optical Setup Dye see page 19 Complex pattern or pattern dynamics in the central spot are the result of these instabilities Some dynamics on the spot fringes does not play any role Getting a better laser mode may require changing the distances between folding mirrors FM 1 and FM 2 and the gain medium with the help of the translation stages For the Matisse Dye changing the distance between pump mirror PM and the dye jet can also help Before you start using the translation stages make sure the knobs of the corresponding lead screws have marks so that you can clearly identify the amount of change you introduce If there is no clearly visible mark make one with e g a felt tip pen Note down the turns and their directions so that you can easily get back to original positions if necessary One full 360 turn of a knob will change the distance by an amount of 0 25 mm Turning knobs clockwise will decrease the corresponding distances mentioned above turning counter clockwise will increase them Ti Sa Matisse Decreasing the mirror distances will increase the laser mode volume and so mitigating
99. only part of the gain provided by the laser medium can used by a specific resonator mode at the locations of the wave s nodes the gain cannot be depleted spatial hole burning effect This can lead to a situation where another resonator mode having its anti nodes at the locations of the nodes of the former mode can start to oscillate and produce a multi mode laser operation case Ring resonators with their running waves do not suffer from this problem but there is the possibility for two modes with the same frequency but running in opposite direction to oscillate This case produces complicated intensity dynamics and can be avoided by introducing an unidirectional device optical diode to allow only modes in one propagation direction to oscillate Apart from adding new elements to the laser another way to reduce the number of modes is to use resonator mirrors that are highly reflective only for a certain range of wavelengths For the Matisse there are five different optical sets Matisse Optical Set Wavelength Range nm MOSI 690 780 Ti Sa MOS2 750 880 Ti Sa MOS3 850 1020 Ti Sa MOS4 550 670 Dye MOS5 650 780 Dye has the same high reflective mirrors as MOSI but a different output coupler Single F requency Tunable Laser Physics 33 Frequency Selective Elements This section gives a description of the frequency selective optical elements used in the Matisse One important parameters of these elemen
100. onversion Factor 0 2 0 21 0 22 0 23 0 24 0 25 0 26 MHz scanrange of 1 Scan Position 194949 Close Figure 72 Scan Device Calibration with Measure will perform a scan with a range of Scan Range and a speed of Wavemeter Scan Speed with the current Scan Device either RefCell or Slow Piezo while measuring the laser frequency over the current scan position After completion of the scan the Conversion Factor MHz scan range of 1 can be calculated Set stores the conversion factor into the Matisse Commander s configuration file to be used by the Scan Setup dialog see page 106 For the scan to be successful the positions of the Thick and Thin Etalon have to be optimized and the corresponding control loops have to be active beforehand About Figure 73 About dialog Matisse Commander 113 About Matisse Commander The About dialog displays System Information like the Model Name and the Serial Number S N of your Matisse Device as well as the DSP and Firmware version of the hardware controller This information 1s important in case of a support request The clickable www link www sirah com will open the Sirah homepage in the default web browser on your computer where you can find news about and updates for the Matisse laser systems and accompanying software CHAPTER 8 114 Maintenance Handling of Optical Components The good condition of all optical components mirrors beam splitters etc is an esse
101. or the thin etalon requires the measurement of the back reflection of the entrance surface of the etalon This diode measures the reflected intensity Matisse Laser Description 19 Optical Set Up Matisse DR Figure 3 Top view of Matisse dye laser head Figure 4 Optical layout of a Matisse dye laser PM Pump Beam Mirror Re directs and focusses the pump laser beam into the dye jet FMI1 Folding Mirror 1 Restores a parallel beam for the ring laser beam after amplification by the dye jet FM2 Folding Mirror 2 Focusses the ring laser beam into the dye jet for spatial mode matching with the pump laser focus DJ Dye Jet The laser gain medium The jet is formed by a flow of dye solution that is pumped by the circulator system into the nozzle Matisse Laser Description 20 BiFi Birefringence Filter The birefringence filter is used as a coarse bandpass filter to determine the emission wavelength of the ring laser The filter assembly is rotated by a stepper motor OC Output Coupler The output coupler forms the exit for the laser beam A fraction of the beam will be emitted by the laser the rest will be directed back into the ring cavity The beam polarization is horizontal M2 Out Of Plane Mirror M2 This mirror is mounted at a different beam height level This will introduce a geometrical rotation of the beam polarization The combination of M2 and the TGG plate forms an optical diode that supports laser activity in a def
102. or to the Matisse laser beam path then thoroughly check beforehand whether a focused back reflection may occur Warranty does not cover damages due to focused back reflection 15 CHAPTER 3 Matisse Laser Description The present chapter gives a brief description of the optical set up of the Matisse as well as its main specifications For a discussion of optical details including step by step instructions for system optimizations please refer to the next chapters Matisse Laser Description 16 Laser Head Titanium Sapphire Models Figure 1 Top view ofa Matisse TX laser head Figure 2 Optical layout E of a Matisse PM1 Pump Beam Mirror 1 Re directs the pump laser beam onto the Titanium Sapphire laser second pump beam mirror PM2 The mirror is used for steering the pump laser beam PM2 Pump Beam Mirror 2 Focusses the pump laser beam into the crytsal through the backside of folding mirror FM1 FM1 Folding Mirror 1 Restores a parallel beam for the ring laser beam after amplification by the Titanium Sapphire crystal Matisse Laser Description 17 FM2 Folding Mirror 2 Focusses the ring laser beam into the Titanium Sapphire crystal for spatial mode matching with the pump laser focus TiSa Titanium Sapphire Crystal The laser gain medium The crystal is cooled by a temperature controlled water EOM Electro Optical Modulator The non resonant intra cavity electro optical modulator is used for fast change of the op
103. ove your Matisse laser to a different location the Matisse Installation chapter contains procedures on how to set up the laser and bring it back to a lasing state Matisse Electronics gives additional and more detailed information on the electronics The FAQ and Troubleshooting chapter tries to help you solve some issues that you may encounter at some time working with a Matisse laser In the Customer Service section you will find the addresses of world wide Service and Sales Centres for Sirah instruments In case of any question remark or problem please do not hesitate to contact us Please read the whole manual before starting to work with your system We strongly recommend to keep a laser logbook You should note all changes of the mechanical or optical set up of your laser Regularly take notes about obtained laser powers together with the corresponding pump power These notes often simplify the identification of possible error sources Finally if you encounter any difficulty with the content or the style of this manual please let us know For your convenience a fax form has been added at the end of this manual which will aid in bringing such problems to our attention Matisse Preface 6 Environmental Specifications CE Electrical Equipment Requirements AC power input 100 240 VAC 50 60 Hz Power Consumption max 700 W Environmental Specifications The environmental conditions under which the laser system will fu
104. p and fixed with respect to the pump laser only two screws will allow to compensate the small day to day shifts of the laser alignment The figure below shows the three off plane folding mirrors M1 M2 and M3 in the Matisse cavity As already mentioned in the Laser Description Chapter M1 is the Matisse outcoupling mirror whereas M3 is equipped with the fast piezo crystal in case of the actively stabilized models TS TX DS and DX The Mirrors M1 and M3 are adjustable even with the top cover of the Matisse closed by means of the four tuning knobs shown above a Knob S Iv tunes mirror M 1 in the vertical sense Knob S 1h tunes mirror M 1 in the horizontal sense Knob S 3h tunes mirror M 3 in the horizontal sense Knob S 3v tunes mirror M 3 in the vertical sense For a fast optimization of a laser already running close to its maximum power it is sufficient to tune one of the two mirrors M 1 or M 3 Observe the Matisse power on your power meter Then very carefully either tune knobs S 1v and S Ih or tune knobs S 3v and S 3h in order to maximize the Matisse power In general the necessary amount of tuning will be very small in the order of a knob rotation of only 1 2 degrees or even less If you turn too far the Matisse will stop lasing In this case immediately come back to the starting position in order to re obtain laser operation and re start optimizing Basic Matisse Operation 53 Thick Piezo Etalon Optimiz
105. pening If the height is not right correct it using the vertical adjustment of PM If you notice clipping of the spots at the rhomb or at the Birefringent Filter BiFi correct it using the horizontal adjustment of PM 9 10 11 12 Matisse Installation 124 Put the beam overlap tool between TM and the Thin Etalon mount Thin E and check the beam height Correct it using the vertical adjustment of TM Remove the beam overlap tool and using a small strip of paper make sure that the beam passes through the TGG plate and hits the middle of M3 This is especially important for the actively stabilized Matisse versions because there M3 is rather small Superimpose the propagation paths of the two fluorescence spots the beam path originating from FM2 and going from the tuning mirror TM to M3 serves as the fixed path to which the beam from FMI will be aligned using M1 and M3 Put the beam overlap tool between the TGG plate TGG and the Thick Piezo Etalon Thick E Bring the spot from FMI closer to the fixed spot using only M1 Then put the beam overlap tool between TM and the Thin Etalon mount Thin E Overlap the spot from FM1 with the fixed spot using only M3 Put the beam overlap tool back to the first position between TGG and Thick E and repeat the procedure To distinguish between the two spots as they get closer alternately block one of the beams while watching the overlap tool After some iterations a precise overlap of t
106. put SMA connector to feed an external signal into the DSP unit USB connector Connects the unit to the USB USB indicator Lights up when the USB is transferring data LED Tuning mirror input select Selects the internal or an external signal source for the piezoelectric actor that controls the tuning mirror 8 Tuning mirror external input SMA connector to feed an external signal into the amplifier module Matisse Laser Description 22 9 Tweeter mirror input select Selects the internal or an external signal source for the piezoelectric actor that controls the tweeter mirror 10 Tweeter mirror external input SMA connector to feed an external signal into the amplifier module 11 Reference cell input select Selects the internal or an external signal source for the piezoelectric actor that controls the reference cell spacing 12 Reference cell external input SMA connector to feed an external signal into the amplifier module 13 Thin etalon manual control Two way switch to control the stepper motor that controls the tilt of the thin etalon 14 Thin etalon indicator Lights up when the etalon motor is running LED 15 Thin etalon error Lights up when an error condition is present at the etalon motor controller unit LED 16 Birefringent filter manual control Two way switch to control the stepper motor that controls the rotation of the birefringent filter assembly 17 Birefringent filter indicator Lights up when the
107. quency Tunable Laser Physics 30 Principle Laser Set p tete uet de Be eva a ie RT Oo eu RE e TR 31 Frequency Selectve Ele mernts 5 i dette ie de cu i usw a c diee aT enon 33 Biretringent Filter eee e ie HE dvi fu i Lite Re hod enda tie ohn re Era 34 Thin Et loti netten nece ep oie o Ree E er I d ce ei ire etd 34 Piezo Etalon DesCriptloft iicet f HE Ote edite du AE 35 Piezo Etalon Dithier ooi toD IRI dee n e EA rea cogere ree o HR re one 37 Optical Diode Unidirectional Device ssssssseseesee eee 38 Frequency Stabilization 39 Side of Fringe frequency stabilization eese nennen eene nennen ene tnenn nennen enne 40 Pound Drever Hall frequency stabilization ssessssssssssssesseseeeeneneren enne 42 Frequency Drift Compensation cerei edere pa rere E c ee rne d EHE rea ee Ug ve oe a ds 45 Using your own reference for stabilizing enne nnne nnne 46 Basic Matisse Operation 47 Starts Up Matisse EE S a Hh DAR e ate e e te o ee eett 47 Start Up Matisse D umet iu ettet ote tut lu ioc cei eae 48 Matisse Power Optimization 2 stet sanete que ice i Se OR E 51 Cavity Mirror Optimizations ace RR ARES TR UR MEAE OU RENTRER Cei Red 52 Contents ii Thick Piezo Etalon Optimization sess ener ener 53 Thin Etalon and Birefringent Filter Optimization eese eene 54 Frequency Setting desse Intt DO Re titii se stig iets noch act titi estes 58 Frequen
108. ram available on the Sirah website Attp Avww sirah com http www sirah com Matisse Commander 68 Main Window Figure 32 Main Window Matisse Commander 1 8 S N 99 99 99 Matisse Birefringent Filter Thin Etalon Piezo Etalon 5 Stabilization Scan Help Current Position 800 0 Laser Power 0 82 Laser Locked 0 702 0 60 3 0 504 m zi 0 402 0 302 0 202 0 10 0 002 Clear Chart Thin Etalon Piezo Etalon Stabilization m Scan Scan Piezo Voltage T Direction Thin Etalon Signal Piezo Etalon Baseline xdi TOME T NET 0 0 25 0 19398 Slow Piezo Voltage 0 00000 0 10000 10 35000 The window contains an indicator for the Current Position of the laser Display Options dialog see page 76 and a time chart of the total Laser Power Clear Chart will erase the time chart history Thin Etalon and Piezo Etalon Control are simultaneous indicator control displays determining the status of the corresponding control loops for the Thin and the Piezo Etalon Thin Etalon Signal displays the Thin Etalon reflex signal and the Piezo Etalon Baseline indicator control gives the voltage baseline applied to the piezo element If this voltage exceeds critical values the numerical indicator will start blinking red In this case use the slider to reset value Changing this value might cause a shift in the laser frequency The Scan indicator control displays the current scan status and there is also th
109. raw the wetted paper over the surface In this case the cleaning effect is caused by adhesion Be careful when cleaning half wave plates They are relatively thin and tend to break if too strong pressure is applied The best solution is to remove dust by applying a gentle flow of clean air or nitrogen rather than wiping the surface of these plates Of course you should clean the optics of your laser system only when not operated That means no pump laser beams should be applied to the Matisse and the entire system should be protected against unintended application of the pump laser In case you are removing optics for cleaning please remove them one by one and switch on and re optimize the laser between two successive optics removals In that way switching on the laser again and keeping its full output power is relatively straight forward Do not forget to completely block the pump beam before removal of each Matisse optics Maintenance 115 If you observe a significantly increased level of scattered light in your laser that cannot be reduced by thorough cleaning check your laser optics for defects In case of damages caused by wrong adjustment of your laser optics you should make sure to correct the alignment to avoid further damaging right before changing the defect optical elements Mirror Exchange The Matisse has been designed with the aim to keep mirror exchange as simple as possible Depending on the specific configuration as
110. rease the pump power until the Matisse starts lasing 22 Your Matisse dye laser should now operate In this case please refer to the following Sections for a quick optimization of the Matisse output power If your Matisse laser is still not operating then decrease the pump power to about 5 W and carefully re check the entire pump beam path Matisse Power Optimization Once your Matisse laser is emitting radiation you should follow the procedures given below for a fast and easy optimization of the laser ring cavity and the angular position of the thin etalon and the birefringent filter On a daily working routine this optimization should take only some minutes and allow you to fully optimize the laser power Before starting the optimization follow the start up procedure given above If not yet done boot the laser control computer and start the Matisse Commander Place a power meter in the Matisse beam and monitor the generated power Basic Matisse Operation 52 Cavity Mirror Optimization Figure 21 Alignment screws of the Matisse three mirror set Screws S Iv and S Ih allow to adjust the reflection direction of Mirror M 1 in the vertical and horizontal direction respectively Screws S 3h and S 3v act similarly on mirror M3 The Matisse laser cavity is designed for excellent long term stability Therefore only minor adjustments are necessary to keep the power of your laser system at maximum level Once the laser is set u
111. refringent Filter Goto Dialog In this dialog you can move the laser to a new position in units determined by the Display Options see page 76 The position of the Birefringent Filter motor position is computed with the help of a calibration function the parameters of which can be calculated in the Birefringent Filter Calibration Table see page 79 Matisse Commander 77 Birefringent Filter Scan Figure 46 Birefringent Filter Scan dialog Birefringent Filter Scan Thin Etalon Reflex Birefringent Filter Scan Total Power 1 0 7 Motor Position 1j 75664 Goto Jaiod P101 in gd D D D D x amp n E 5 i amp k 1 o w 1 o N 0 17 i i i i i 1 i 1 1 i 70 7 73000 73250 73500 73750 74000 74250 74500 74750 75000 75250 75500 75750 Birefr Filter motor position Options x In this dialog a scan over the Birefringent Filter motor positions can be executed Two signals are recorded the total laser power and the intensity of the thin etalon s reflex The scan is centered around the current Birefringent Filter motor position The scan range and increment can be set in the Birefringent Filter Scan Options see page 78 press the Options button or F2 The current motor position is shown as a cursor vertical red line in the Birefringent Filter Scan graph and in the Motor Position control You can change this position by changing the position contr
112. ringent Filter motor scan Blue curve thin etalon reflex Red curve total Matisse power Both in arbitrary units During laser operation especially when the laser wavelength is scanned the position of the thin etalon is actively controlled by the laser electronics The error signal for the electronics it the laser power reflected from the etalon as measured by diode D 2 divided by the total laser power as measured by diode D 1 This error signal is minimum for the optimum etalon position The set point of the thin etalon and also the position of the birefringent filter need to be checked and optimized for each wavelength Execute the optimization process in the following order Birefringent Filter Click on Scan in the Birefringent Filter menu of the Matisse Commander main window Start a Birefringent Filter scan A typical result is displayed in the next figure where the total laser power blue curve and the Thin Etalon reflection are shown as function of the Birefringent Filter motor position in stepper motor steps The third element in the graph is a red vertical line cursor indicating the original motor position before the scan was executed O Birefringent Filter Scan Thin Etalon Reflex Birefringent Filter Scan Total Power unn D 6 T 0 5 Motor Position 259663 4aM0d 301 x 2 D a c 2 m E i G im Goto 0 07 1 1 1 i 1 1 170 3 253000 254000 255000 256000 25
113. se substances Especially smoking is strictly forbidden In the following list some further safety precautions for the handling of dye solutions are given If possible use an outlet for handling solvents and dye solutions Otherwise ensure a sufficient ventilation of the workshop place Do not eat drink and smoke during your work with solvents and dye solutions Avoid all kinds of open fire Repair damages or leakage in the dye circulator system immediately without modifying the technical construction of the pump systems Install a suitable fire extinguisher next to your dye laser Safety P recautions 14 Focused Back Reflection Danger Focused back reflections of the pump as well as the Matisse laser s beam represent a serious hazard for both your personal safety and optical components Remember that an uncoated glass surface reflects 4 of the impinging light and even with an appropriate anti reflective coating 0 596 of reflection are normal These reflections may be focused from both convex and concave surfaces depending on the orientation of the surface to the direction of light In the focus the light intensity is often high enough to damage the surfaces of other optical components and to represent a serious hazard for eyes and skin The optical design of your Matisse laser has been set up very carefully by Sirah Laser und Plasmatechnik GmbH If you intend to make any modifications to the pump laser beam path
114. se the RefCell Control Loop has to be active Only meaningful for Matisse TS DS or higher You can also set a Conversion Factor that gives a relation between the nominal scan piezo range and the effective laser frequency change If you have a Matisse TS DS you can measure this factor with the help of the Reference Cavity see RefCell Properties Measurement see page 95 If you have a wavemeter and a corresponding Wavemeter plugin e g the HighFinesse wavemeter plugin available at the Sirah website integrated into the Matisse Commander then you should use the Scan Device Calibration with Wavemeter procedure in the Wavemeter see page 71 menu because this gives also the sign of the conversion factor that is important for advanced function of the wavemeter plugin Determining the Conversion Factor in the general case for a Matisse and a wavelength frequency device is as follows define a a scan for the Matisse with a specific scan range e g 0 1 see Scan Setup dialog see page 106 Measure the laser frequency at the start of the scan execute the scan and measure the laser frequency at the end of the scan Divide the frequency difference in MHz by the scan range and enter the result into the Conversion Factor control Matisse Commander 109 ControlScan Setup ControlScan Setup Scan Device Slow Piezo Birefringent Filter 590 885 Calc BiFi Factor Thin Etalon r 3500 Thick Piezo Etalon 213 59999 Slow P
115. ss to the Matisse device by the status data gathering loop of the Matisse Commander The Snapshot mode will wait until the ring buffer contains new data and will display therefore a fully real time snapshot of the control loop behaviour regardless of the time scale it it working on Snap will trigger another snapshot Clear will erase the data displays Figure 40 Hardware Configuration dialog Matisse Commander 7A Control Loop Live View Options These controls determine the delay time for the continuous read out of the various control loops data in the Control Loop Live View dialog see page 73 Device Hardware Configuration Hardware Configuration E3 Hardware Modules Slow Piezo DAC Reference Cell DAC Birefringent Filter Motor Controller Thin Etalon Motor Controller Fast Piezo Piezo Etalon C Pound Drever Hall Controller C Intra Cavity EOM Controller The various Matisse models possess different electronic hardware components In this dialog you can activate or deactivate these components To make this change permanent you have save the active configuration see Device Configuration see page 69 Changes will come into effect at the next start of the Matisse hardware controller Control Switch Off Level Figure 4l Level dialog Switch Off Switch Off Level Switch Off Intensity Level Jo 1 The Switch Off Level is the total laser power level below which the control loops
116. suffer additional losses at the various Brewster surfaces in the resonator CHAPTER 5 39 Frequency Stabilization For many laser applications is not only necessary to have a single frequency laser but also to have a very stable frequency itself 1 e a small effective laser linewidth It is possible to suppress laser intrinsic frequency noise by using external frequency references Frequency stabilized Matisse are using highly stable reference resonators that still allow to have a scannable laser by scanning the reference in contrast to using e g atomic frequency standards There are two stabilization schemes exploited with the Matisse for the TS DS version it 1s the side of fringe scheme for the TX DX and TX DX light version it is the Pound Drever Hall method These two schemes differ in their complexity and achievable stabilization results as will be described in the following sections Frequency Stabilization 40 Side of Fringe frequency stabilization The concept for this method is relatively simple when you scan the laser frequency and observe the transmitted light from the reference cell you can observe the well known Airy function spectrum of the reference resonator The stabilization idea is now to set the frequency of the laser so that it corresponds to a point of the flank of one of the resonator s transmission resonances side of fringe A control loop adapts the laser s frequency in a way that keeps the tra
117. t closer alternately block one of the beams while watching the overlap tool After some iterations a precise overlap of the two spots at both positions can be achieved Do a check by putting the beam overlap tool between FM2 and the Piezo Etalon Thick E If the adjustment is good the two spots will also be superimposed here Remove the color filter and the two pin holes Make sure that there is no obvious dust on the optics where the pump light is inciding or going through If there is dust refer to chapter 8 Handling of Optical Components for cleaning Increase the pump power to at least 5 W If the laser is not already lasing observe the fluorescence shapes in the laser output Carefully pull at the mirror knobs at the laser output side M1 and M3 to see if there is a short laser flash and adjust the respective mirrors to reach lasing Optical Alignment Procedure Matisse Dye This section gives a procedure how to align the various optical components of the Matisse Dye laser to achieve lasing The optical components are described in the Matisse Dye Optical Setup see page 19 section 1 The pump radiation has to be p polarized Your laser might have a half wave plate installed in the entrance opening for rotation of the polarization Step 6 below describes how to adjust the half wave plate The distance between pump laser and Matisse laser should not be too big about 10 to 30 cm You might find a beam tube grey plastic
118. t with the fundamental frequency can effectively interact with the resonator i e exciting a field inside the resonator Part of this excited field will be coupled out back by the first reference cell mirror The sideband parts are effectively just reflected back by the first reference resonator mirror Error Signal a u Figure 16 Theoretical PDH Error Signal Frequency Stabilization 43 The quantity that is now observed with a photo diode is the light reflected back from the reference resonator The reflected light is deflected from the in going beam path by a combination of a doubly passed quarter wave plate and a polarizing beam splitter to the Fast Diode In general photo diodes act as an intensity detector F square of the electrical field Having three different frequencies in the spectrum means that the resulting diode signal will not only contain a constant component but also beat signals with frequencies that corresponds to the various differences of the three optical frequencies Especially the beat signals having a carrier frequency of the EOM modulation frequency v are now used for generating a suitable frequency error signal For that purpose the diode signal is mixed with the modulation signal for the EOM which filters out just the desired signals with the v carrier As a complication there are actually two signals with this carrier frequency but only one of which is usable as an error signal Fortunately the two
119. tay in the utmost right position on the displayed motor position scale Birefringent Filter Scan Thin Etalon Reflex Birefringent Filter Scan Total Power 0 6 0 5 0 5 iz Ll Motor Position 256413 Goto x 2 A Lj 9 x a 5 D 03 3 a E S E i i e N 2n 0 1 0 07 1 1 1 1 1 1 79 3 253000 254000 255000 256000 257000 258000 259000 260000 Birefr Filter motor position Thin Etalon Click on Control Position Scan in the TE Thin Etalon menu Press Start The Thin Etalon performs a scan in the vicinity of of its current position A typical result is shown in the figure below The power reflected from the Thin Etalon and the total laser power are measured simultaneously as function of the etalon position The third element in the graph is a red vertical line indicating the original motor position before the scan which will allow you to move the etalon in a well controlled way near a minimum of the curve representing the reflected power Figure 24 This window indicates the power reflected from the thin etalon as well as the total laser power for different positions of the thin etalon Basic Matisse Operation 56 Set Thin Etalon Control Position Thin Etalon Reflex L Thin Etalon Scan Total Power 0 871 0 5 Set Motor Position t 20000 y x 2 3 g c ar 3 3 m i w I amp Y i zi Goto
120. the Birefringent Filter Calibration Table Birefr Filter Scan Options on page 80 press the Options button or F2 The range of motor position that is imported into the Calibration Table see page 79 is determined by the two red cursor vertical red line in the Birefringent Filter Scan graph Change this range by dragging the cursors to other positions Pressing Start will execute the scan that can be aborted by the Stop button Birefringent Filter Calibration Table Birefr Filter Scan Options only available with wavemeter support These controls determine the Scan Start Scan Start and Scan Increment of the Birefringent Filter Calibration Table Birefr Filter Scan see page 80 Matisse Commander 81 Thin Etalon Thin Etalon Control Setup Thin Etalon Control Setup Figure 49 TE Control Setup dialog Average Proportional Gain Integral Gain Flank Orientation J Left Gain Parameter Scaling Thin Etalon Control In this dialog you can determine the behavior of the Thin Etalon control loop by setting the loop s parameters like the Proportional Gain Integral Gain and Average which is the number of measurements the loop is averaging to compute the error signal Thin Etalon Control will switch the control loop on or off Flank Orientation determines on which flank of the Thin Etalon parabola structure in the Thin Etalon Scan see page 82 the laser is stabilized Gain Parameter Scaling enables the linear sc
121. the TE Control Position setting procedure The Initial Motor Position is the position the TE motor is moved to when you call the TE Control Goal dialog If it is set to a negative number the motor will not not be moved The thick piezo etalon ensures that all except one longitudinal mode have so high losses that laser emission is not possible Therefore the spacing of the etalon must be matched to an multiple of the favored longitudinal mode s wavelength Because of the tight spacing and in order to be able to perform a scan the spacing is actively controlled The control loop is based on a lock in technique and the etalon spacing is varied by a piezo drive The lock in measures the response of the laser to an externally introduced perturbation The perturbation is a slight modulation of the etalon spacing The modulation follows the amplitude of a sine wave with a modulation frequency f mod The response of the laser is the variation in the total laser power measured at the power diode Matisse Commander 84 Piezo Etalon Control Setup Figure 52 Basic setup for piezo etalon Piezo Etalon Control Setup Basic Advanced Amplitude Phase Shift 5 323 32 0 9 sp M f 100 4 150 J Control Loop Active 180 180 CD J 0 Waveform This dialog has two tabs Basic and Advanced Amplitude This parameter controls the amplitude of the sine modulation that is applied to the piezoelectric actor The val
122. the laser beam into the reference resonator open the Pound Drever Hall Waveforms see page 102 display and set Scan Upper Limit to 0 1 Scan Lower Limit to 0 Oversampling to 128 and Sampling Mode to Average Set the Multiplexer control to Diode Signal Minimize the signal strength by adjusting the mirror reflecting the back reflected light from the resonator onto the photo diode The signal has a nominal value range from 0 5 to 0 5 and is inverted Lower numbers mean higher signal value Adapt the filters so that you have good signal to noise ratio set the Multiplexer control to Mixer Output Choose a scan interval and decrease its size about 0 03 so that you can clearly see the PDH error waveform with the biggest amplitude Adapt the value of the DSP Offset so that the signal s baseline outside of the PDH error signal is around zero The mixer signal has a nominal value range from 0 5 to 0 5 The PDH error signal should be in the range of 0 2 to 0 2 open the Fast Piezo Control Setup see page 90 dialog set the Lock Point to either a value slightly lower than the maximum of the PDH error signal or to a value slightly higher than the minimum value Set Setpoint to 0 make sure the slow piezo Baseline is in the middle of its range Activate the lock by clicking on the RefCell Control LED indicator in the main window or ticking the Control On item in the PDH Stabilization menu Troubleshooting Matisse Commander 99 If
123. the mount TGG TGG Plate The TGG plate is made from Terbium Gallium Garnet and acts as a Faraday rotator when exposed to a strong magnetic field The combination of M2 and the TGG plate forms an optical diode that supports laser activity in a defined direction Note The magnetic field is generated by two powerful permanent magnets Be careful when using tools close to the device Piezo E Piezo Etalon The piezo etalon selects a single longitudinal mode from the spectral range that is determined by the configuration of output coupler birefringence filter and thin etalon To maintain the exact match of etalon and longitudinal mode the spacing of the etalon is dithered by an piezoelectric actor and a lock in scheme is used to control the etalon spacing Matisse Laser Description 18 TM Tuning Mirror The exact emission wavelength of the cavity is determined by it s length The tuning mirror is attached to a long stroke piezoelectric actor to allow the selection of this wavelength This device is used for low bandwidth woofer correction of the Matisse s emission wavelength when active wavelength control is enabled only available in Matisse TS and TX models DI Integral Diode The lock in control for the piezo etalon requires the measurement of the temporal behaviour of the integral intensity of the ring laser For this purpose the leak intensity on the backside of the out of plane mirror M2 is used DE Etalon Diode The control loop f
124. tical path length of the ring cavity The effect is used for high bandwidth correction of the Matisse s emission wavelength Note The device is only present in the Matisse TX Thin E Thin Etalon The thin etalon is used as a bandpass filter To provide tunability the tin etalon is attached to a motor driven mount A step motor controls the horizontal tilt angle of the etalon BiFi Birefringence Filter The birefringence filter is used as a coarse bandpass filter to determine the emission wavelength of the ring laser The filter assembly is rotated by a stepper motor OC Output Coupler The output coupler forms the exit for the laser beam A fraction of the beam will be emitted by the laser the rest will be directed back into the ring cavity The beam polarization is horizontal M2 Out Of Plane Mirror M2 This mirror is mounted at a different beam height level This will introduce a geometrical rotation of the beam polarization The combination of M2 and the TGG plate forms an optical diode that supports laser activity in a defined direction M3 Tweeter Mirror M3 This mirror is mounted on a piezoelectric actor Changing the voltage applied to the actor will change the position of the mirror and ultimately the optical path length of the cavity The effect is used for mid bandwidth correction of the Matisse s emission wavelength Note The Matisse TR has no active control of the emission wavelength in this case the mirror is fixed directly to
125. tinue working before at least 15 minutes of bubble free operation Bubble free operation means that you do not hear any gurgling or splashing of dye under the spray guard 16 Lift the spray guard to its upper position and fix it there as shown in the first figure Carefully clean remaining spilled dye with a Q tip Take great care not to cross the dye jet with the Q tip Strong dye spray all over the laser would be the consequence 17 Set your pump laser to a very low pump power 0 2 W or less Open the pump laser shutter or remove the external beam dump and apply pump power to the Matisse 18 Make sure that the pump laser is correctly coupled into the dye laser Basic Matisse Operation 51 19 Close the Matisse top cover 20 Increase the pump power until the Matisse laser threshold is reached The energy level necessary for the start of laser operation depends on the used dye and the wavelength As a rough indication if pumped with a 532 nm beam and used with a high gain red dye the Matisse should start lasing at about 1 5 W input power 21 Slowly increase the pump power up to 5 W At this pump energy most pump Matisse laser configurations should result in an operating dye laser However for very low gain dyes or at wavelengths at the edge of the tuning range even higher pump power might be necessary Before further increasing the pump power please check again that the pump beam correctly enters the dye laser Then slowly inc
126. total power at that position For keeping the Thin Etalon synchronized with the movements of the Piezo Etalon the reflection from one etalon facette is monitored and compared to the total laser intensity The TE control loop will adjust the TE position so that the ratio of these two signals is kept constant Choosing the right control point is important for achieving stable modehop free single mode operation of the laser After a scan you should see a curve for the thin etalon reflex that consist of a succession of parabolas with minima Set the cursor by dragging it with the left mouse button pressed on the left flank of a parabola close to its minimum and press Set if Flank Orientation is selected to be Left Set the cursor by dragging it with the left mouse button pressed on the right flank of a parabola close to its minimum and press Set if Flank Orientation is selected to be Right Thin Etalon Reflex Thin Etalon Scan Total Power Start I Set Motor Positior 16750 Goto Flank Orientat Jj Right Options T OK Figure 51 TE Control Position Options dialog Piezo Etalon Matisse Commander 83 If Set is not used the motor will stay in the scan s end position when you close the dialog Thin Etalon Control Position Options TE Control Goal Options Initial Motor Postion A 1 Scan Range e 3500 Scan Increment 1 50 These controls determine the Scan Range and Scan Increment of
127. ts except for the Birefringent filter is the Free Spectral Range FSR as described above The FSR of the Matisse ring resonator is about 160 MHz The following figure illustrates the effect on the laser mode spectrum of the Matisse Ti Sa laser by the various frequency selective elements in the case of the MOS2 optics set Intrinsic emission spectrum of titanium sapphire 950 1000 MOS 2 750 870 nm 60 THz 375 000 Modes Birefringent Filter Thin Etalon FSR 250 GHz UTE Mode spacing 160 MHz Thick Etalon FSR 20 GHz Figure 7 Laser mode spectrum in the case of the MOS2 optics set The schematic setup of the Matisse TR 1s shown in the figure below to illustrate the geometric arrangement of the various frequency selective elements Tuning Titanium Sapphire Thick Etalon Unidirectional Mirror Crystal Piezo Driven Device Pump Laser Thin Etalon Birefringent Filter Output Input Motor Driven 3 Plates Motor Driven Coupler Figure 8 Matisse TR Setup Birefringent Filter Thin Etalon Single F requency Tunable Laser Physics 34 The Birefringent Filter uses the effect of birefringence and the polarization selective property of the laser resonator to achieve frequency selection It consists of three plates having thicknesses in the ratio of 1 3 15 For different optics sets Birefringent Filters with different plates thickness have to be used in general For MOS 2 the thinnest plate has a thi
128. u find this threshold value Choose a value that is about 10 smaller than the threshold value If you cannot find a threshold you might have already started above it so decrease the Integral Gain until you will find a decrease in the frequency noise go to the Pound Drever Hall Control Setup see page 100 dialog decrease the Attenuator value by steps of 5 until you see an increase in the displayed frequency noise There is a threshold for this parameter below which the control loop starts to oscillate and to increase the frequency noise increase the Attenuator until you find this threshold value Choose a value that is about 3 lower smaller than the threshold value If you cannot find a threshold you might have already started above it so increase the Attenuator until you will find a decrease in the frequency noise Matisse Commander 100 Pound Drever Hall Control Setup Only available for Matisse TX DX and TX light These control parameters influence the various input and output signals of the Pound Drever Hall unit Pound Drever Hall Control Basic Advanced Phaseshift 15 DSP Offset 21123 4 T Attenuator j 23 5 dB PDH Multiplexer Input ej Slow Side EOM Sideband Modulation On Intra Cavity EOM active Co Figure 60 Pound Drever Hall Control Basic Parameters Setup basic parameters i DSP Offset will change the baseline of the Phase Mixer signal Choose a value so that
129. ue for the Amplitude should never exceed 50 Depending on the actual etalon values between 5 and 25 should work for almost all cases Bigger values make for a cleaner waveform less amplitude noise but might decrease the power output of the laser Too big values for the Amplitude will show up as more than one mode per FSR in the monitor spectrum Phase Shift This parameter controls the phase shift that is applied before the convolution of modulation waveform and waveform detected at the integral diode is calculated You should find a range of values or just one value where for each value the Piezo Etalon Waveform is stationary i e its form stays the same apart from some amplitude noise Choose a value from the center of the range Note The Phaseshift parameter can only be changed in discrete steps of 180 oversampling points Control Loop Active This button controls if the action that is calculated by the control loop is applied to the piezo If the control loop is inactive the modulation is still applied Waveform This button opens the Piezo Etalon Waveform see page 86 window Matisse Commander 85 Advanced Settings Figure 53 Advanced tab of the piezo control dialog etalon Piezo Etalon Control Setup Basic Advanced Dither Frequency Control Loop Feed Forward Oversampling Average Phase Shift i116 Yo i sp lt j x r 2 Sample Rate Proportional Gain y 100 48 kHz 0 98614 A j
130. um Close The graph shows the transmission spectrum for the confocal reference cell A scan over the cell s piezo actuator voltage is performed within an interval determined by Scan Upper Limit and Scan Lower Limit values are in a range of 0 to 0 7 The Oversampling parameter gives the number of sampling points It cannot be higher than 512 The Sampling Mode decides which characteristics of the waveform the DSP is looking for finding Maximums Minimiums or computing the Average using the full internal waveform at the ADC The Autoscale Y Axis property determines whether to automatically adjust the maximum and minimum values of that axis If the property is set to false you can manually adjust these values by clicking onto the axis with the left mouse button and entering new numbers Set Setpoint will set the setpoint of the Fast Piezo control loop see page 90 to the displayed FPZ Setpoint The value is calculated to be the amplitude value at the Full Width At Half Maximum points of the currently displayed transmission spectrum Matisse Commander 94 RefCell Frequency Noise only available for Matisse TS DS RefCell Frequency Noise d x Frequency Deviation 0 6 FSR RefCell MHz J 600 o de Lu Finesse J 13 3664 N 1 eo Uu RefCell Spectrum Peak Intensity 0 365513 N 1 0 4 Per c s 3 2 gt o a 2 v c o P cC o rg RefCell Spectrum 0 6 Intensity Of
131. ur laser at the wavelength of maximum power output of the current configuration This wavelength and the obtained power will be mainly defined by the mirror set and dye crystal your are using Optimize the system for that wavelength and take notes about pump power Matisse wavelength and obtained Matisse power After moving the system you should re install the laser for with the same configuration before eventually changing the wavelength or the pump power During transport your laser is exposed to unavoidable vibrations which might cause damages to the laser system if no adequate precautions are taken One precaution is to install transport safeties for the four linear translations and for the Birefringent Filter lever inside the Matisse laser Do not forget to remove the transport safeties when reinstalling the laser Optical Alignment Procedures Optical Alignment Procedure Matisse Ti Sa This section gives a procedure how to align the various optical components of the Matisse Ti Sa laser to achieve lasing The optical components are described in the Matisse Ti Sa Optical Setup section see page 16 1 The pump radiation has to be p polarized Your laser might have a half wave plate installed in the entrance opening for rotation of the polarization Step 6 below describes how to adjust the half wave plate 2 The distance between pump laser and Matisse laser should not be too big about 10 to 30 cm You might find a beam tub
132. vide more information Display Off will switch off the controls on the Main Window see page 68 This may be helpful if the error occurs repeatedly in the data gathering loop for the various indicators You can switch on the display again in the Display Options dialog see page 76 You have to choose if you wish to Continue with the application execution or if you want to Exit Matisse Commander Matisse Commander and all its dialogs follow a key navigation standard Key s Function lt Enter gt Execute Function Change Settings lt Esc gt Abort Dialog Function F1 Show context sensitive Help F2 Open Dialog Options Matisse Commander 67 Wavemeter Support Firmware Update The functionality of the Matisse Commander software can be enhanced by using devices capable of measuring the laser s current wavelength further referred to as wavemeters New functions like a Goto Wavelength routine that sets the laser to any desired wavelength position within its tuning range could be implemented Wavemeter support for the Matisse Commander program which is developed with LabVIEW is achieved by using LabVIEW application libraries plug ins for different kinds of wavemeters that conform to a specific interface Further details are given in the Matisse Programmer s Guide available on the Sirah website www sirah com http www sirah com The firmware of the hardware controller can be updated via the Firmware Updater prog
133. voltage applied to the scan piezo and the upper and lower limits of the scan respectively The value written in the Position field when opening the Scan Setup represents the current voltage on the scanning piezo which is driving the scan piezo If you set the laser to a specific position e g the start frequency of the scan to be performed prior to opening the Scan Setup menu then you can easily deduce the piezo voltage corresponding to this laser frequency just by checking the Position value o upper limit E rising falling 9 speed speed T volts sec volts sec 8 a c b RB a aaa lower limit time Rising Speed V s and Falling Speed V s are the voltage change per second see diagram above Scan Stop Mode determines if and when the scan stops at upper or lower limit There are eight pre defined scan modes first you may choose if the scan starts with increasing or decreasing voltage Additionally you may choose if the scan stops once it arrives at the upper voltage limit the lower voltage limit either of them or neither of them Scan Control switches the scan off or on Once the scan is defined it can be started or stopped by simply clicking on Scanning in the Scan menu or on the Scan LED in the Matisse Commander window Basic Matisse Operation 62 Shut Down Matisse T Switch off the pump laser Exit the Matisse Commander Switch off the Matisse electronics box and in the case of a Matiss
134. wer B AN 0 6 0 5 0 5 Set a ES 1 Motor Position 259663 Goto Thin Etalon Reflex eo wo 1 4BNOd e301 B N 1 0 1 0 07 1 1 1 1 1 1 73 3 253000 254000 255000 256000 257000 258000 259000 260000 Birefr Filter motor position o mt Press Set and note down the wavelength frequency Now move the red cursor to the center of the next step of the Thin Etalon reflex signal and press Set again A comparison between the current and former frequency should reveal a difference with an absolute value of one FSR TE The change in frequency going from step to step in one direction is monotonous So what you have to do is to find the direction and motor position range step in which the absolute value of difference between current and desired frequency decreases and gets minimal This positioning procedure of the Birefringent Filter motor will allow you to set the laser within the range of 0 5 x FSR TE around the desired frequency for a standard configuration this corresponds to about 125 GHZ The tuning procedure for the Thin Etalon is analogous to the one for the Birefringent Filter Open the Thin Etalon Control Position Scan dialog and execute a motor scan resulting in the figure below Set Thin Etalon Control Position Thin Etalon Reflex Thin Etalon Scan Total Power O 8 0 5 Set Motor Position 20000 J Thin Etalon Reflex ABNIO BIOL
135. y User Configurations can be saved deleted or newly created Active gt File will save the active configuration to a text file File gt Active will load a configuration from such a file Note Listing the various configurations saving or creating a configuration will interrupt the execution of the Thick Piezo Etalon control loop Matisse Commander 71 Advanced Options amp Tools Interactive Shell Matisse Command Command MOTBI POS ha Response ae IDN Matisse TS S N 05 25 20 DS gt MOTBI POS lt MOTBI POS 66664 Figure 35 Interactive Command Shell You can directly communicate with the laser device using low level device commands Commands typed into the Command control followed by pressing Enter will be sent to the Matisse controller and executed The controller s response will be shown in the Response indicator A history of sent commands to choose from can be accessed by using the pull down menu of the Command control To send the current command repeatedly you have to press Send Again You can also arrange commands line wise in a text file and load this file via Batch File The text lines will be sent until an End Of File or the word END is encountered Figure 36 TE Signal display Figure 37 Wavemeter Integration dialog Figure 38 Wavemeter Removal Matisse Commander 72 Thin Etalon Signal Monitor TE Signal Monitor 0 4 0 5 0 6 0 2 0 3 0 7 0 8 Averaged
136. your everyday work with the Matisse but for those users who have to move their laser to another location and to re install it afterwards e g in another laboratory Your Matisse is mounted in an extremely stable housing and transport does not cause any major problem Installation is also quite simple if the transport has been well prepared So please do not touch your system before having read the present chapter completely Installation Requirements The installation of the Matisse laser requires an area of about 1050 mm x 360 mm The laser needs to be mounted on a vibrational isolated optical table together with the corresponding pump laser The Matisse housing is equipped with legs designed for vibrational isolation allowing to set the height of the entrance for the pump laser beam to a value between 140 155 mm for the Ti Sa model and to a value between 145 155 mm for the Dye model In a first step you have to set your pump laser in such a way that its beam runs in a height within these limits and parallel to the plane on which the Matisse is to be mounted Advantageously you perform this setting before mounting the Matisse Matisse models TS and TX are equiped with a reference cell This cell requires additional space of about 450 mm x 360 mm Transport Matisse Installation 118 The main condition to keep installation after transport easy is to start with a running system Before moving the system you should operate yo
137. zo Setpoint This value defines the control goal for the fast piezo control loop The control loop will try to stabilize the laser at a wavelength that corresponds to the Setpoint value at the DSP input Matisse TS DS Use a position in the centre of the transmission flank as value for Setpoint See Reference Cell Waveform see page 93 on how to determine this point For Matisse TS DS systems the Lock Point will be automatically set to the same value as the Setpoint Matisse Commander 91 Matisse TX DX The Setpoint defines the point on the steep flank of the Pound Drever Hall mixer signal see page 102 to which the laser s wavelength is stabilized Choose a value that has has the same value as the signal has far from any resonance Lock Point This value defines an initial Setpoint that will be used when the laser starts a lock or re lock process The Lock Point is useful for Pound Drever Hall systems where it is not possible to distinguish between a laser system that is on the resonance or far awway from the resonance Hence the laser will first lock to a non zero value determined by the Lock Point parameter that is only present at a resonance After the lock is attained the laser will be smoothly moved from the Lock Point to the Setpoint Fast Piezo Control The Fast Piezo Control button will switch the control loop on or off Changing the controls values has an immediate effect on the control loop Matisse Commander 92

Matisse User's Guide - Spectra

Contents

Download Pdf Manuals

Related Search

Related Contents