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Hurricane i.book - Spectra

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1. 2 3 Figure 2 4 Hurricane i CE CDRH Radiation Control Drawing 2 7 Figure 2 5 CE CRDH Labele 2 8 Figure 3 1 Principle of Chirped Pulse Amplification 3 2 Figure 3 2 Principle of Pulse Stretching Using Negative GVD 3 3 Figure 4 1 Front Pariel ge ses etae ep ym im donee a AG Ee EN Re VOR ER A Yee E 4 1 Figure 4 2 Output Side Panel 4 2 Figure 4 3 Umbilical Panel Hurricanei 4 3 Figure 4 4 SDG II Front Panel 4 5 Figure 4 5 Optical Design of the BWD 4 6 Figure 4 6 SDG II BackPanel 4 7 Figure 4 7 Motion Controller 4 9 Figure 5 1 Interconnect Diagram 1 kHz Hurricane i 5 3 Figure 5 2 Hurricane i Control Diagram 5 4 Figure 5 3 Flow Diagram for Chiller Water 5 5 Figure 5 4 Outline Drawing Hurricanei 5 6 Figure 5 5 SDG II Outline Drawing 5 6 Figure 6 1 Typical Autocorre
2. 2 7 CE Declaration of Conformity 2 9 Sources for Additional Information 2 10 Chapter 3 General Description 3 1 Ti Sapphire Laser Theory hmm emer 3 1 Chirped Pulse Amplification 3 2 Regenerative Amplification ce n 3 6 The Synchronization and Delay Generator SDG II 3 7 Hurricane i Control Software 3 8 Performance Specifications hr 3 8 vii Hurricane i Integrated Ti Sapphire Amplifier System Chapter 4 Controls Indicators and Connections 4 1 Hurricane i Assembly External Controls 4 1 The Synchronous Delay Generator SDG II 4 4 Motion Controller 4 9 Chapter5 Installation 5 1 Requirements for Installation 5 1 Evolution 15 Power Supply 5 2 M i Tai Power Supply nii ssh ripreso SL A Ade Nu DEP d EEG 5 2 Interconnection Diagram ssec Ee Lt EXTR REM dee E RO e d ex EX 5 3 CASERA rt E ID IS RA du teca eee 5 5 Mechanical Specifications o ooccoccocconccre ren 5 6 Chapter 6 Operatlon sc ia A A A eee ee EE 6 1 Startup Procedure hh hr hr 6 2 Shutdown Procedure
3. Figure 8 4 Intracavity Pulse Train 6 While monitoring the pulse train adjust the M turning mirror that directs the seed pulse into the resonator Reduce the pulse build up time to the minimum possible that is adjust M so that the pulse train moves to the left on the oscilloscope screen 7 Adjust the SDG II OUT 2 DELAY until the intracavity pulse train looks like that in Figure 8 5 Figure 8 5 Intracavity Pulse Train with Correct Timing 8 9 Hurricane i Integrated Ti Sapphire Amplifier System Compressor Adjustment 8 10 Note 10 Connect the REGEN OUT PD output of the Hurricane i to an oscillo scope You should see a single stable output pulse Refer to the description in the section Rear Umbilical Panel on page 3 While viewing the output mode adjust mirror PM to obtain the round est and most homogenous mode If the pulse amplitude is stable but there is evidence of a secondary pulse make a slight adjustment to the OUT 2 DELAY control If this does not produce a stable and single cavity dumped pulse adjust the OUT 1 DELAY control by 10 ns If a stable single cavity is still not produced contact your Spectra Physics service engineer The alignment of the beam through the compressor should remain stable To optimize compressor performance first confirm that the output beam is round and even in intensity Then look at the radiation pattern on the com pressor grating with an I
4. STRETCHER GRATING COMPRESSOR GRATING Stretcher Compressor i pump beam stretched seed pulses stretched amplified pulses Regenerative Amplifier see Figure 7 3 22 N SM1 see Figure 7 4 PTO FARADAY ISOLATOR Evolution Pump Laser Mai Tai Seed Laser Figure 7 1 Hurricane i Beam Path The treatment of the beam and its path through the Hurricane i are described in the following sections For clarity a number of simple optical 7 1 Hurricane i Integrated Ti Sapphire Amplifier System elements in the Hurricane i apertures beam expanding lenses etc have been omitted from these diagrams Also omitted for clarity are the spec trometer in the stretcher compressor cavity and its optical elements The abbreviations used in Figure 7 1 are used throughout this manual to identify optical components A few of the more complex elements require some initial description Faraday Isolator uses the polarization properties of the beam to protect Mai Tai optical components Combined with the half wave plate 2 it absorbs any back reflected power that is generated in the amplifier and absorbs pulses that are not selected for amplification Polarizer is an optical element that as used in the Hurricane i regenera tive amplifier is transparent to horizontally polarized light and reflects ver tically polarized li
5. eer hr 6 4 Optimizing Pulsed Output 6 4 Control Software 2 4 svar area ed ben RD LEE vee hid ened eee eee eli 6 6 Chapter 7 OpticalLayout 7 1 The Hurricane i Beam Path 7 1 The Martai Beam NEE 7 2 The Stretcher and Compressor Beam Paths 7 3 Chapter 8 Maintenance and Service 8 1 Defeating the Cover Interlocks 8 1 Troubleshooting Guide 8 2 EV Fault Software Indicators 8 4 Cleaning the Optics 8 6 Performance Optimization 8 7 Customer Service use nr liana her Io dene Ep ere 8 12 Return of the Instrument for Repair 8 13 Service Centers ci Re ein 8 14 Notes Report for Problems and Solutions viii Table of Contents List of Figures Figure 1 1 Block Diagram of the Hurricane i Assembly 1 2 Figure 2 1 Labels Appropriate for Warning Signs 2 2 Figure 2 2 Folded Metal Beam Target 2 2 Figure 2 3 Hurricane i Emission Indicator
6. 3 etc This allows the output pulse rate of the Hurricane i to be changed without changing the repetition rate of either the Evolution or Mai Tai which might affect amplifier stability The largest factor available corresponds to a 1 Hz repetition rate i e 1000 for a 1 kHz system 5000 for a 5 kHz system The reduction fac tor is not shown only the actual output frequency is displayed SYNC ENABLE control selects synchronized LED is on or unsynchro nized LED is off mode If both the LED and error lamp are on the sync source is absent or the Mai Tai has stopped mode locking Cycle the SYNC ENABLE button after correcting the error condition The Hurricane i will not operate correctly in unsynchronized mode Synchronized mode allows the sync outputs to fire based on the current pump laser delay setting OUT 1 DELAY and the next available seed pulse Essentially it provides a way to fire the Hurricane i input Pockels cell based on sync signals from two different circuits the Evolution Q switch signal and the Mai Tai pulse train SYNC ERROR indicator when this lamp is on and the SDG II is in syn chronized mode either the sync signal is absent or the Mai Tai laser has stopped mode locking BWD PD1 PD2 and RESET controls see the Bandwidth Detector section below MODE control this button selects CONTINUOUS repetition rate firing based on the input trigger or SINGLE SHOT firing The selected mode is indica
7. Temperature changes or similar variations in the environment of the Hurri cane i may necessitate an adjustment to optimize the pulsed output When the Hurricane i output has been selected to exit from the front panel the PEAK POWER MONITOR displayed on either the SDG panel or the SPECT panel can be used to optimize the power of the individual output pulses Adjust the compressor length using the MOTOR CONTROL which displays relative values only to achieve the highest value on the PEAK POWER MONITOR display Optimizing Pulse Compression The compressed pulse should look like that in Figure 6 1 To achieve the shortest pulse view the compressed pulsed using an auto correlator The shortest pulse is achieved using the motor controller which optimizes the compressor length by changing the position of the horizontal retro reflector Operation At 038 Y i 203 54 PA e t n E r en Sn 1 Le 4 f e il T Ed i moncone ef 35m 20045 Figure 6 1 Typical Autocorrelation of a Well Compressed Pulse A quick method to optimize the compressor length is by observing the pulsed output on a white business card When the compressor length is cor rect the high peak power of pulse will cause the beam to appear blue in the center due to frequency doubling on the card Warning The peak power of a typical system pulse is insufficient to ignite com W mon types of paper nevertheless always use caution when ins
8. default value is set at the factory SDG COM PORT default value is set at the factory When lit the following indicators signal a communications error with the corresponding subsystem e g a cable is unplugged a subsystem is turned off Verify the cables are properly connected refer to the Interconnect Dia gram in Chapter 4 and that the subsystem is turned on appropriately For additional assistance contact your Spectra Physics representative EV COM ERR Evolution 15 error SPECT COM ERR spectrometer error LJ COM ERR LabJack error MT COM ERR Mai Tai error SDG COM ERR S DG II error MT ID ERR Mai Tai initialization error The software did not receive a proper response to a query about the software revision The is for use in troubleshooting by a trained technician LABJACK ERROR MESSAGE display shows the LabJack error messages intended for use by Spectra Physics service personnel LOG SAMPLE TIME S control sets the interval in seconds for writing entries to the log file LOG FILE display shows the path and file name for the event log A new log file is created every time the control program is started The file name is the time stamp of the first entry written to it YYYYMMDD HHMMSS MAI TAI ERROR MESSAGE display shows the most recent outstanding Mai Tai error and code for use by Spectra Physics service personnel Hurricane i Integrated Ti Sapphire Amplifier System Warning The
9. picosecond or 10 second radio frequency standard cubic feet per hour self phase modulation transverse electromagnetic mode Titanium doped Sapphire wavelength XV Hurricane i Integrated Ti Sapphire Amplifier System xvi Unpacking and Inspection Unpacking Your Laser Your Hurricane i laser was packed with great care and its container was inspected prior to shipment it left Spectra Physics in good condition Upon receiving your system immediately inspect the outside of the ship ping containers If there is any major damage holes in the containers crushing etc insist that a representative of the carrier be present when you unpack the contents Once uncrated carefully inspect your laser system as you unpack it If any damage is evident such as dents or scratches on the covers or broken parts etc immediately notify the carrier and your Spectra Physics sales repre sentative Keep the shipping containers If you file a damage claim you may need them to demonstrate that the damage occurred as a result of shipping If you need to return the system for service at a later date the specially designed container assures adequate protection Warning Spectra Physics considers itself responsible for the safety reliability and performance of the Hurricane i laser only under the following con ditions All field installable options modifications or repairs are performed by persons trained and authorized by Spectra Ph
10. DELAY 2 NS control sets the OUT 2 delay from 0 to 1275 ns DELAY 3 NS control sets the SYNC OUT delay from 0 to 1275 ns READ SET control determines whether the values for synchronous delays of the SDG II are controlled by software or by the SDG II unit itself When READ is selected the software reads and displays values that have been set on the SDG TI When SET is selected the software can change the SDG II values using input from the entry fields listed above When the READ is selected clicking STOP will cause the OUT 1 and OUT 2 controls to turn off thereby stopping the emission of amplified pulses from the Hurricane i Note that the system may still emit light from the Mai Tai laser When SET is selected clicking STOP will cause the OUT 1 and OUT 2 con trols to change to READ mode Clicking STOP again will then turn off the production of amplified pulses Operation EV SYSTEM Panel EVOLUTION STATUS Q SWITCH MODE QSW FREQUENCY kHz ELAPSED TIME EV STO EXTERNAL 6 JLT 1 La lin QSW PULSE WIDTH uS sala HOLD OFF 6 ON RF OFF Figure 6 3 The Evolution System Panel EV STOP indicator illuminates when the Evolution 15 is in the STOP state the pump diode lasers are turned off and the internal shutter is closed EV FAULT indicator illuminates when there is a problem with the Evolu tion 15 Select the EV FAULT tab to display more information EV COUNTDOWN indicator illuminates wh
11. Figure 2 2 VISIBLE AND OR INVISIBLE VISIBLE AND OR INVISIBLE LASER RADIATION LASER RADIATION AVOID EYE OR SKIN EXPOSURE TO AO EVE OR SON Er OSE TO DIRECT OR SCATTERED RADIATION CLASS 4 LASER PRODUCT POWER WAVELENGTH S AND PULSE WIDTH DEPEND ON PUMP WIDTH DEPEND ON PUMP OPTIONS AND OPTIONS AND LASER CON POWER WAVELENGTH S AND PULSE FIGURATION LASER CONFIGURATION CLASS IV LASER PRODUCT SEE MANUAL 0451 8080 Figure 2 1 Labels Appropriate for Warning Signs Figure 2 2 Folded Metal Beam Target Caution Use of controls or adjustments or the performance of procedures other than those specified herein may result in hazardous radiation exposure Follow the instructions contained in this manual for safe operation of your laser At all times during operation maintenance or service of your laser avoid unnecessary exposure to laser or collateral radiation that exceeds the accessible emission limits listed in Performance Standards for Laser Prod ucts United States Code of Federal Regulations 21 CFR1040 10 d Any electronic product radiation except laser radiation emitted by a laser product as a result of or necessary for the operation of a laser incorporated into that product Laser Safety Mode Locked Laser Pump Laser Safety Devices Emission Indicators Danger Laser Radiation The Hurricane i uses a CW mode locked Ti sapphire laser the Mai Tai as a see
12. flips the ends of the spectrum and returns the beam to the lower left side of the grating 5 The redder wavelengths now take the shorter path 5 The beam reflects off the grating and travels to the vertical retro reflector 6 6 The beam is stepped upwards an inch and is sent back to the top left side of the grating 7 which reflects it to the upper part of the right horizontal retroreflector 8 7 The horizontal retroreflector flips the beam around again 9 and sends it back to the grating 10 where the beam is finally combined as a round compressed beam and reflected toward the exit over Me 11 8 When the pulse exits the compressor it has been compressed close to the duration of the seed pulse The Ti Sapphire Regenerative Amplifier 7 4 i from Stretcher to Compressor Il vertically polarized light CH Ma PT NR ic a CMs Joy NEE ane 1 O CM Na PC d Figure 7 3 Regenerative Amplifier Beam Path pump beam not shown The Seed Beam Path 1 Horizontally polarized pulses from the stretcher are rotated to vertical polarization by the polarization rotating periscope PT and directed into the amplifier cavity by Ma Note Optical Layout 2 The Ti sapphire rod cut at Brewster s angle for horizontally polarized light reflects the vertically polarized pulses off its surface and directs them toward the first cavity mirror CM4 At this point the pulsed beam is in the amplifier cav
13. forced to take the longer path This allows the redder wavelengths to catch up and reduce the pulse duration to close to its original length The retroreflector in the compressor is mounted on a track for easy transla tion along the beam path which allows for the fine adjustment required to compensate for small routine fluctuations in the dispersion that takes place in the amplifier cavity Fine adjustment of this retroreflector translation is provided by a de motor and motion controller The property of GVD or chirp for a pulse described above is actually a non linear effect and the chirp contains components that depend upon the higher order powers of the pulse bandwidth For the Hurricane i amplifier however these higher order chirp effects are kept to a small enough level so that additional complexity in the optical design is not required Pulse Selection and Pockels Cells 3 4 Note Once the pulses leave the stretcher selecting a pulse for retention in the amplifier cavity is accomplished by using of the polarization of its light This polarization is controlled by means of Pockels cells in the amplifier cavity A Pockels cell is an electro optic device that without an applied voltage has essentially no effect on light transmitted through it When the proper high voltage is applied however the crystalline material in a Pockels cell acts as a 14 waveplate and rotates the polarization of trans mitted light by 45 each time a
14. the Mai Tai Do not change this setting unless instructed to do so by an authorized Spectra Physics representative Note that this power may change to a different pre set optimized level if the Mai Tai output is set to a different wavelength ACTUAL POWER indicator displays the actual output power level of the pump laser that is inside the Mai Tai CURRENT SET control sets the current level of the Mai Tai pump laser as a percentage of the factory pre set value of its range of operating current Do not change this value unless instructed to do so by an authorized Spectra Physics representative Note that this setting may change to a different pre set optimized value if the Mai Tai output is set to a different wavelength ACTUAL CURRENT indicator displays actual current level of the Mai Tai pump laser as a percentage of its operating range Current is related to pump output power and the current required to maintain a given output level will increase over time as the diode lasers for the pump laser age WAVELENGTH SET control changes the Mai Tai output wavelength Refer to the Mai Tai User s Manual for the Mai Tai tuning range The wavelength should always be set to 800 nm when the Mai Tai is operating as the seed laser for the Hurricane i WAVELENGTH READ indicator displays the actual Mai Tai operating wavelength This reading should always be 800 nm or close to it when the Mai Tai is operating as the seed laser for the
15. FAULT Panel COVER USER FLOW LBO TEMP QSW LOW FREQ QSW VSVYR QSW TEMP QSW PULSEWIDTH uS control sets the width of the internal trigger pulse to the Q switch driver This value should be 5 0 us for 1 kHz opera tion ELAPSED TIME indicator shows the cumulative time the Evolution 15 laser has been on DRIVER TEMP al Hurricane tEvolution 30 Loo Eva 30 log 20021009 txt DIODE TEMP OVER VOLTAGE Se OWER CURRENT OWER POWER PROT FAULT CHECKSUM ERROR Figure 6 4 The EV Fault Panel 6 10 The following indicators are primarily for use by service personnel Some types of faults however can be cleared by the user Refer to Chapter 8 COVER USER indicator denotes either a the remote interlock that connects to the rear of the Evolution 15 power supply has been activated or b during service of the system one or more of the micro switches under the cover of the Evolution 15 head have been activated FLOW indicator illuminates when chiller water flow is less than 2 0 GPM LBO TEMP indicator illuminates when the LBO temperature is outside a preset range around the factory set point QSW LOW FREQ indicator illuminates when the QSW MODE is set to EXTERNAL and the external trigger source drops below 500 Hz QSW VSWR indicator illuminates when one or both of the QSW RF con nectors on the back of the Evolution 15 power supply are disconnected QSW TEMP indicator illuminates when the thermal sensor in eith
16. Hurricane i RF PHASE SET control sets the timing of the RF driver for the mode locker This setting has been set at the factory to optimize the Mai Tai out put Do not change this value unless instructed to do so by an authorized Spectra Physics representative Note that this setting may automatically change to a different pre set opti mized value if the Mai Tai wavelength is changed RF PHASE READ indicator displays the timing of the RF driver for the Mai Tai mode locker MODELOCKER ENABLE switch enables or disables modelocking Mode locking must be enabled when the Mai Tai is operating as the seed laser for the Hurricane i MODELOCKER indicator illuminates if modelocking is enabled Operation MAI TAI INFO Panel EE Ria Diode Current Diode Temp 100 00 WEET Setted History Buffer Cm n ji MaiTai Warmed Up ERC ae 0 0454 8270N 6 00 0454 8340D L Msg System Error Code ME Figure 6 6 The Mai Tai Info Panel WARMUP display shows the percentage of warm up time elapsed MAI TAI WARMED UP indicator illuminates when the Mai Tai is 100 warmed up POWER display shows the average Mai Tai output power in Watts SHG STATUS display shows the status of the temperature of the doubling crystal in the Mai Tai pump laser It reads Settled when the crystal has stabilized at its operation level HISTORY BUFFER display lists the entries of the history buffer which can be navigated by cl
17. Hurricane i HSD 2 TRIG connector to turn on the output Pockels cell in order to eject the amplified pulse SYNC OUT DELAY display control and connector the display shows the selected delay from 0 to 1275 ns when the user can send a trigger signal to an oscilloscope or similar device The control knob works the same way as the one for OUT 1 DELAY This delay is synchronized to but independent of OUT 1 DELAY and OUT 2 DELAY The output is a 1 5 us positive TTL pulse The bandwidth detector BWD protects the regenerative amplifier optics from damage caused if the stretcher cannot adequately reduce the peak power of the Mai Tai pulses before they are amplified For example this problem could result from blocking a portion of the beam in the stretcher The BWD relies on the signals from two fast photo detectors placed behind the tall stretcher end mirror Figure 4 5 This mirror transmits about 596 of the incident light to the detectors If the signal from either detector falls below a threshold set for each version of the Hurricane i the BWD is activated FRA Photodiodes D2 Stretcher Stretcher End Mirror 27 Grating OUT Figure 4 5 Optical Design of the BWD When the seed laser is stable and properly mode locked the BWD permits the SDG II to function normally When the BWD senses a lack of signal a relay will disable the trigger signal that fires the Pockels cells No pulses are selected for amplification thus p
18. LC Warning W Operation The following procedures will result in laser emission from the Hurri cane i output port Ensure that all persons in the room are wearing ade quate eye protection Safety glasses rated at OD4 or greater for all lasing wavelengths present in the system must be worn at all times when oper ating the Hurricane i Also ensure that the anticipated beam is safely terminated It is recommended that the following equipment be kept on hand e a power meter capable of measuring between 10 mW and 20 W of average power from 527 nm to 900 nm e g Spectra Physics 407A e a fast CRT analog oscilloscope capable of 300 MHz or better eg Tektronix 2467 7104 or TDS 3052 e a fast photodiode with a 2 ns rise time or better eg Electro Optics Technology Model ET 2000 R viewer and IR card e anautocorrelator e g Spectra Physics SSA This chapter contains procedures for starting stopping and operating the Hurricane i system Familiarize yourself with the functions available through the software interface before attempting to use the system Do not click on a function or change a parameter through the software interface without first understanding the action Note that many functions are reserved for service or factory personnel Unauthorized use of these functions may damage your system and void your warranty Verify that all connectors are plugged into the Mai Tai power supply they should never be
19. Timing 8 9 Figure 8 6 Radiation Pattern on Compressor Grating ees 8 10 List of Tables Table 2 1 Fuse Ratings for SDG II 2 5 Table 2 2 Label Translations AAA EEEE lh 2 8 Table 3 1 Hurricane i Specifications 3 8 Table 5 1 Physical Specifications for Hurricane i 5 6 Table 8 1 Fault Indicators Evolution 15 8 4 Hurricane i Integrated Ti Sapphire Amplifier System Danger Laser Radiation Danger Danger Warning Warning ESD Caution Note Don t Touch Eyewear Required d y U d V 8 A Warning Conventions The following warnings are used throughout this manual to draw your attention to situations or procedures that require extra attention They warn of hazards to your health damage to equipment sensitive procedures and exceptional circumstances All messages are set apart by a thin line above and below the text as shown here Laser radiation is present Condition or action may present a hazard to personal safety Condition or action may present an electrical hazard to personal safety Condition or action may cause damage to equipment Action may cause electrostatic discharge and cause damage to equip ment Condition or action may cause poor performance
20. controls available under the following tabs are reserved for use by trained and authorized Spectra Physics personnel Do not use them EV SET Panel EV SYSTEM EVFAULT EV SET MAITAISET MAITAIINFO LABJACK SPECT SDG GENERAL SETTINGS FACTORY Calibration Pro input source A D or Manual Evo Cal Input Manual Power i Manual D A D Spare scaled Ev Cal Points Reading b 000 Reading Figure 6 10 The EV Set Panel LABJACK Panel I EV SYSTEM EVFAULT EVSET MAITAISET MAITAIINFO LABJACK SPECT SDG GENERAL SETTINGS FACTORY atte Calib Sait 0 00000 Meter CPMH aya WA ll 0 00000 Ca ENT fo IR PowerMon D 00000 Meter 2 RPM Al4 Spare 00000 0 00 ENT D POE TU A D Spare A D Spare scaled Calibration Input f Manual A D Spare Multiplier Gm Figure 6 11 the LabJack Panel FACTORY Panel EV SYSTEM EVFAULT EVSET MAITAISET MAITAIINFO LABJACK SPECT GENERAL SETTINGS FACTORY Gain CPYolt DI D2 D3 DA Dal mm feat eat eat ENKEN DATA 3 E IRPYolt 000 Gra 6 Gra am aa oco um Figure 6 12 The Factory Panel 6 18 Chapter 7 The Hurricane i Beam Path Optical Layout The Hurricane i is designed to be low maintenance and trouble free It is however a very sophisticated opto electrical system Any maintenance and troubleshooting that may be needed requires an understanding of the beam path and internal adjustments inside the Hurricane i
21. disconnected if they are refer to Chapters 4 and 5 for information on reconnecting them Verify the chiller reservoir has been filled to the correct level Verify it is set to 21 C AC line voltage to the crystal heater circuit in the Evolution 15 power supply is always present when the power supply is plugged in even when the ac switch is off The chiller must be left on while the power supply is connected to mains voltage or permanent damage will result to the LBO doubling crystal in the Evolution 15 6 1 Hurricane i Integrated Ti Sapphire Amplifier System Startup Procedure Read through this entire procedure before performing it for the first time Note that the component lasers as well as the Hurricane i system itself need time to warm up in order to achieve stable operation 1 The chiller should already be on and stable at 21 C 2 Start the Mai Tai power supply warm up sequence a Turn on the power supply ac switch b Turn on the power supply key switch A sequence of messages described in the Mai Tai User s Manual will appear on the LCD display on the power supply followed by a series of boot tests After completing the boot tests the LCD display will read Success Boot test passed The LCD screen will now display a four line message similar to MAITAI MODE IR Power Pump power 4 650W Warmup 90 c Wait for the warm up percentage to reach 100 The Mai Tai power s
22. excites the regenerative amplifier Refer to Figure 1 1 The mode locked Ti sapphire Mai Tai seed laser contains its own pump laser The Mai Tai and its component lasers are described in detail in its own manual included with the Hurricane i system The Evolution 15 is a diode pumped Q switched frequency doubled pump laser and it too is described in detail its own manual shipped with this system Control of the Hurricane i is via comprehensive yet intuitive Windows based control software provided pre installed on a laptop computer included with the system Sophisticated onboard diagnostics enable full control of system functions through the software interface Amplification takes place in the Hurricane i when a pulse selected from the Mai Tai seed laser passes through the Ti sapphire amplifier rod which has been optically excited by the Evolution 15 pump laser A single pass of an optical pulse through such a rod will result in about a 3 x amplification however regenerative amplification enables the pulse to pass multiple times through the rod resulting in a much higher overall gain A seed pulse of only a few nano Joules can be amplified by a factor of 10 Normally the damage threshold of the optical elements limits the maxi mum energy to which the pulse can be amplified However using Chirped Pulse Amplification CPA allows the Hurricane i to operate without risk of optical damage Originally developed for radar systems CP
23. front panel of the Evolution power supply TRIGGER OUT connector provides a 200 ns fixed output trigger signal The input pulse trigger to the SDG II produces this TRIGGER OUT signal before it is sent to the three adjustable outputs on the front panel INTERLOCK ENABLE switch enables or disables the 5V DC connector When the switch is up the connector is functional and the center pin of the BNC is grounded When the switch is down the connector is disabled 5V DC connector input accepts an input signal from a safety interlock switch for example a switch that senses when the laboratory door has opened If this connector is enabled and the safety interlock switch opens OUT 1 DELAY and OUT 2 DELAY will be disabled The use of the 5V DC connector as a safety switch will not disable the Evolution or Mai Tai lasers These lasers have their own safety inter locks Please refer to their specific manuals Motion Controller Controls Indicators and Connections The motion controller provides translation of the horizontal retro reflector assembly in the compressor This movement changes the length of the beam path in the compressor which provides the fine adjustment needed to compensate for small changes in the dispersion that take place in the ampli fier cavity The controller connects to the DCMOTOR BNC connector on the Hurricane i umbilical panel The controller can be either battery powered or used with the DC adap
24. grating and thus the bandwidth of the amplified pulse before compression SEED SPECTRUM fiber optic connector SMA links the spectrometer to the detector for monitoring the reflection from the stretcher grating and thus the bandwidth of the seed pulse before stretching and amplification DAQ connector USB connects the computer to the data acquisition unit BWD connector is a 4 pin connector 3 pins are used that connects to the BWD connector on the back of the SDG II Mai Tai Umbilical Port is the connection for Mai Tai control and power including the fiber optics for the diode laser pump source for the Mai Tai This is the standard Mai Tai umbilical connection refer to the Mai Tai User s Manual It is accessed through a space in the Hurricane i panel 40 MHz Output connects by means of a BNC cable to the RF SYNC connector on the back of the SDG II to synchronize the capture of the mode locked seed pulses 80 MHz Output not used in the Hurricane i system The Synchronous Delay Generator SDG II During normal operation the Hurricane i is controlled by means of the software interface see Chapter 6 It is possible however to use the man ual controls available on the system to control the amplified output The SDG TI controls the selection of pulses from the Mai Tai and the repeti tion rate of the pulsed output of the Hurricane i First it acts as a counter that selects mode locked seed pump pulses at eithe
25. in major United States cities When calling for service inside the United States dial our toll free number 1 800 456 2552 To phone for service in other coun tries refer to the Service Centers listing located at the end of this section Order replacement parts directly from Spectra Physics For ordering or shipping instructions or for assistance of any kind contact your nearest sales office or service center You will need your instrument model and serial numbers available when you call Service data or shipping instruc tions will be promptly supplied To order optional items or other system components or for general sales assistance dial 1 800 SPL LASER in the United States or 1 650 961 2550 from anywhere else This warranty supplements the warranty contained in the specific sales order In the event of a conflict between documents the terms and condi tions of the sales order shall prevail The Hurricane i is protected by a twelve 12 month warranty All mechan ical and optical parts and assemblies are unconditionally warranted to be free of defects in workmanship and material for the warranty period At its election Spectra Physics will repair or replace without charge components that prove defective during the warranty period The obligation of Spectra Physics is limited to repair covered under the warranty return procedure described on the following page Equipment repaired or replaced is war ranted only for the remai
26. other controls have been properly set and there are no active interlocks the Hurricane i will start producing amplified pulses when this button is selected STOP button stops operation of the regenerative amplifier when the READ SET control is in READ mode See the READ SET control description below REGEN EMISSION indicator illuminates when the amplified output is available although if the Hurricane i shutter is closed there will be no emission The internal shutter used to block the amplified Hurricane i output is controlled through the panel activated by selecting the SDG tab on the lower half of the Main screen INTERLOCK indicator illuminates when the BWD circuit has tripped and thus needs to be reset OUT 1 control corresponds to the OUT 1 DELAY control on the SDG II It synchronizes the firing of the input Pockels cell to capture the current seed pulse with the firing of the Q switch in the Evolution 15 laser OUT 2 control corresponds to the OUT 2 DELAY control on the SDG II It synchronizes the firing of the output Pockels cell to eject the amplified seed pulse with the firing of the Q switch in the Evolution 15 laser SYNC OUT control corresponds to the SYNC OUT DELAY control on the SDG II It turns on off the delay between the firing of the output Pockels cell and the transmission of a trigger pulse for use by a laboratory instru ment DELAY 1 NS control sets the OUT 1 delay from 0 to 1275 ns
27. responsibility that the Hurricane i Integrated Ti Sapphire Regenerative Amplifier System with SDG II Controller manufactured after July 1 1999 meets the intent of EMC Directive 89 336 EEC 1989 for electromagnetic com patibility and 73 23 EEC 1973 for low voltage directives Compliance was demonstrated to the following specifications as listed in the official Journal of the European Communities EMC Directive 89 336 EEC 1989 EN 50081 2 1993 Emissions EN 55011 1998 CISPR 11 1997 Class A radiated and conducted emis sions EN 50082 2 1995 Immunity IEC 801 2 Electrostatic Discharge IEC 801 3 RF Radiated IEC 801 4 Fast Transients Low Voltage Directive 73 23 EEC 1973 EN61010 1 1996 Safety requirements for electrical equipment for measure ment control and laboratory use Part 1 General Requirements EN60825 1 1997 Safety of laser products Part 1 Equipment classification requirements and users guide I the undersigned hereby declare that the equipment specified above conforms to the above Directives and Standards Bruce Craig Director of Engineering and Marketing 6 Spectra Physics Solid State Lasers April 5 2002 2 9 Hurricane i Integrated Ti Sapphire Amplifier System Sources for Additional Information The following are some sources for additional information on laser safety standards safety equipment and training Laser Safety Standards 2 10 Safe Use of Lasers Z136 1 1993 American Na
28. the Mai Tai laser Set the Evolution 15 power to 15 A Use the mirror PM to center the green beam through PL and PL Use PM to direct the beam to the center of the Ti sapphire rod To measure the output power of the regenerative amplifier place the detector for a power meter in the beam between PT and Mg The shut ter located in this position will have to be removed temporarily Place a target typically a white business card in front of PT On the SDG II enable OUT 1 DELAY and disable OUT 2 DELAY Connect an oscilloscope to view the output of REGEN OUT PD Set the Evolution 15 to the appropriate power level for the Hurricane i and start the Evolution 15 For correct power level refer to the instal lation report provided with the Hurricane i The amplifier resonator should now lase If it does not adjust the pump beam across the Ti sapphire crystal face until the pump beam is superimposed onto the intracavity beam The lasing status can be determined either by viewing the target in front of PT with an IR viewer or by monitoring while using appropri ate safety eyewear the fluorescence of the Ti sapphire amplifier crys tal the fluorescence decreases as the amplifier lases When the amplifier lases while viewing the Q switched pulse on the scope adjust PM to achieve the highest amplitude pulse with a corre sponding minimum buildup time Enable OUT 2 DELAY and adjust its timing to cavity dump the maxi mum power
29. when handling optics Hold one sheet of lens tissue over the optic to be cleaned 1 2 3 4 Place a single drop of methanol on top of the lens tissue 5 Drag the lens tissue across the optic only once 6 If a residue of solvent is left on the optic repeat the procedure using less solvent and a new lens tissue until no residue remains For hard to reach optics 1 Wear finger cots or gloves 2 Fold a piece of lens tissue to form a pad approximately 1 cm wide 3 Hold the pad with a hemostat so that only the folded edge protrudes 4 Saturate the pad with methanol or acetone and shake off the excess sol vent An Reach slightly onto one edge of the optic and wipe the surface of the optic toward the outside in one motion Be careful that the tip of the hemostat does not scratch the optic Maintenance and Service Performance Optimization The parameters that should be optimized for good performance of the Hurricane i are e Stability of the mode locked pulse train e Alignment of the Mai Tai beam into the regenerative amplifier e Regenerative Amplifier performance Compressor optimization e Alignment of the Evolution 15 beam into the regenerative amplifier nical personnel who are experienced in maintaining and adjusting high power infrared lasers They should not be attempted by someone who is inexperienced at these tasks Caution n The procedures described in this section are for the convenience of tech A
30. 3 Verify the time delay between turn on of the emission indicator and starting of the laser it must give enough warning to allow action to avoid exposure to laser radiation 4 Verify the beam attenuator shutter operates properly when com manded from the laptop PC controller and that it closes when the con troller is disconnected or the keyswitch is turned off Verify it actually blocks access to laser radiation 0 39 uW for continuous wave operation where output is limited to the 400 to 1400 nm range 2 6 Laser Safety CE CDRH Radiation Control Drawings 3 NI Top View 1 7 Right Side View Optional Mai Tai Port 5 4 5 4 QA QAEI Left Side View 4 5 Emission Indicator gt AE Output End View Figure 2 4 Hurricane i CE CDRH Radiation Control Drawing see Labels in Figure 2 5 Hurricane i Integrated Ti Sapphire Amplifier System SPECTRA PHYSICS LASERS P O BOX 7013 VISIBLE AND OR INVISIBLE LASER RADIATION MT VIEW CALIFORNIA 94039 7013 AVOID EYE OR SKIN EXPOSURE TO DIRECT OR SCATTERED RADIATION MANUFACTURED CLASS IV LASER RODCUT MONTH YR MAX OUTPUT lt 5W MODEL d WAVELENGTH 700 1000nm THIS LASER PRODUCT COMPLIES PULSE LENGTH 30fs 6DS 565 5575 WITH 21 CFR 1040 AS APPLICABLE M
31. A involves temporally stretching the pulse to reduce its peak power then amplifying the pulse while it is at reduced power and finally compressing the ampli fied pulse to near its original duration The compact enclosed amplifier with active cooling provides stable opera tion and reduces sensitivity to environmental changes The compressor sec tion allows easy correction of the higher order phase distortion that is typical of ultrafast amplifier systems The Hurricane i produces pulses slightly longer than 100 fs near 800 nm at a repetition rate of 1 KHz An option exists for 5 kHz output Contact your Spectra Physics representative for more information about this option Windows is a trademark of Microsoft Corporation 1 1 Hurricane i Integrated Ti Sapphire Amplifier System 1 2 Note Evolution Pump Laser Ld Mai Tai Seed Laser Regenerative Amplifier Stretcher Compressor Figure 1 1 Block Diagram of the Hurricane i Assembly A Hurricane i system comprises six main components the Hurricane i assembly a notebook PC with LabWindows control software the Synchronization and Delay Generator SDG II the power supply for the Mai Tai laser the power supply for the Evolution 15 laser the chiller In addition to these components a small motion controller is included to fine tune the compressed Hurricane i output A detailed description and instructions for oper
32. ADE IN U S A CE Warning Label 1 Identification Certification Label 2 VISIBLE AND OR INVISIBLE LASER RADIATION AVOID EXPOSURE WHEN OPEN AND INTERLOCK DEFEATED VISIBLE AND OR AVOID EYE OR SKIN EXPOSURE TO DIRECT INVISIBLE LASER OR SCATTERED RADIATION RADIATION IS EMITTED CLASS IV LASER PRODUCT 808 5275 FROM THIS APERTURE Danger Interlocked Housing Label 3 CE Aperture Label 4 Part 1 CE Aperture Label 5 CE Electrical Warning Label 6 Part 2 Figure 2 5 CE CRDH Labels Table 2 2 Label Translations Label French German Spanish Dutch CE Rayonnement visible et ou Austritt von sichtbarer und Radiaci n l ser visible y o Zichtbare en of onzichtbare Warning invisible exposition dan oder unsichtbarer Laser invisible Evitar la exposici n laser straling Vermijd bloots Label gereuse de l il ou de la peau strahlung Augen und Hau de los ojos o la piel a la radia telling aan ogen of huid door 1 au rayonnement direct ou dif tkontakt mit direkter Strahlung cion ya sea directa difusa directe of gereflecteerde stral fus Appareil a laser de oder Streustrahlung ver Producto l ser Clase IV ing Klasse 4 laser produkt Classe 4 Puissance maxi meiden Laser Klasse IV Max Potencia m xima 5 W Lon 532 nm maximaal uittredend mum 5 W Longueur D onde imale Ausgangsleistung lt 5 gitud de onda 700 1000 nm vermogen 15 W 700 1000 nm Duree d impul W Longitud de pulso 30 fs 6 zie handleiding s
33. H VOLTAGE tr A n O MER STOBER Va d g Gel A LIS TRIGGER IN Figure 4 6 SDG II Back Panel Power connector and switch provide ac input power for the SDG II 110 220 Vac The unit includes EMI protection a amp fuse and an on off I 0 switch HIGH VOLTAGE HV1 HV2 connectors provide 1 6 kV dc output con nected by means of high voltage cables to the HSD1 and HSD2 connections for the Pockels cells on the Hurricane i umbilical panel used on 1 kHz systems only 4 7 Hurricane i Integrated Ti Sapphire Amplifier System 4 8 Note si Warning W Systems that operate at a 5 kHz repetition rate use a separate high volt age power supply to drive the Pockels cells The HV1 and HV2 connec tors on the SDG II are not used on these systems Keep these outputs capped when the auxiliary high voltage power supply is used BWD ON switch see Bandwidth Detector above BWD connector see Bandwidth Detector above RS 232 connector serial port allows computer control of the SDG II Refer to Chapter 6 Operation for information on computer control of the system RF SYNC connector attaches to the 40 MHz Mai Tai output connector see Figure 4 3 by means of a high speed cable to synchronize capture of the seed pulse in the amplifier Jitter 1s specified at lt 250 ps TRIGGER IN connector accepts TTL compatible 0 50 kHz input from the SYNC OUT connector on the
34. Hurricane i Integrated Ti Sapphire Amplifier System User s Manual S Spectra Physics 1335 Terra Bella Avenue Mountain View CA 94043 Part Number 0000 300A Rev B May 2004 Preface This manual contains information you need in order to safely operate maintain and perform routine service for your Hurricane i system The system comprises the Hurricane i assembly which includes the regenera tive amplifier along with the seed laser and pump laser the power supplies and chillers needed for the two lasers included in the assembly the syn chronization control module for the system the SDG II and the portable computer with pre installed Windows based control software for operat ing the Hurricane i system Chapter 1 Introduction contains a brief description of the Hurricane i system and its components Chapter 2 contains vital important about safety The Hurricane i is a Class IV laser and as such emits laser radiation which can permanently damage eyes and skin This section contains information about these hazards and offers suggestions on how to safeguard against them To minimize the risk of injury or expensive repairs be sure to read this chapter then carefully follow these instructions Laser Description includes basic laser theory regarding the Ti sapphire crystal and a description of the chirped pulse amplification technique used in the Hurricane i It also contains a more detailed description of the
35. Hurricane i amplifier System specifications are also included The next chapter describes the Hurricane i connections controls and indi cators and is followed by a chapter that outlines how to prepare your labo ratory for the installation of the system Spectra Physics will send a service representative to install the Hurricane i the first time Spectra Physics does not guarantee the performance of this system unless the Hurricane i is installed by an authorized Spectra Physics representative This chapter includes outline drawings and electrical and mechanical specifications Operating the Hurricane i amplifier is relatively simple using the control software provided with the system This software is described in Chapter 6 Operation Chapter 7 Optical Layout describes the beam path and components of the Hurricane i assembly An understanding of how the amplifier operates is essential to understanding the maintenance procedures listed in Chapter 8 Maintenance and Troubleshooting The latter contains procedures that help keep the Hurricane i performing optimally The section on trouble shooting is intended to help you guide your Spectra Physics field service engineer to the source of any problems Windows is a trademark of Microsoft Corporation Hurricane i Integrated Ti Sapphire Amplifier System Do not attempt repairs yourself while the unit is still under warranty instead report all problems to Spectra Physics fo
36. R viewer The pattern should look like that shown in Figure 8 6 Figure 8 6 Radiation Pattern on Compressor Grating The components referred to in this procedure are shown on the figures in Chapter 7 Optical Layout Install the removable aperture in the holder near Mg Install the second aperture in the holder between the grating assem blies Adjust PT to center the beam on the first aperture Rotate the compressor grating so that the beam passes by it and strikes the second aperture Adjust Me to center the beam on the second aperture Iterate Steps 3 and 5 until the beam is centered on both apertures Rotate the compressor grating back into position The beam pattern on the grating should look like the pattern shown in Figure 8 6 If it does not be certain the compressor grating has been properly rotated back to its original position Set the compressor length for optimum compression as described in Chapter 6 Operation Maintenance and Service Alignment of the Pump Beam Note si In the following procedure the regenerative amplifier is initially oper ated as a Q switched laser pumped by the Evolution 15 This procedure assumes that the Evolution 15 pump laser is operating properly Please refer to the Evolution 15 User s Manual for details of operation The path of the pump beam is shown in Figure 7 4 H ES ipe DIA 11 12 13 14 15 16 Close the shutter for
37. These labels state that power must be off before the power supply covers can be removed Fuses Refer to the Mai Tai and the Evolution 15 user s manuals supplied with the Hurricane i for the values and locations of the fuses in those systems The fuse for the Hurricane i is located on the SDG II Table 2 1 Fuse Ratings for SDG II 120 Vac 220 Vac F1AH 250V Slow Blow FO 5AH 250V Slow Blow Maximum Emission Levels The following is the maximum emission level possible for this Hurricane i amplifier system Use this information for selecting appropriate laser safety eyewear and implementing appropriate safety procedures This value does not imply actual system power or specifications Emission Wavelength Maximum Power 690 to 1080 nm 3W Pump laser emission 527 nm 20W Fiber diode laser emission 809 nm 26 W CW each fiber CDRH Requirements for Operating the Mai Tai Using the RS 232 Interface and Command Language The Hurricane i laser system complies with all CDRH safety standards when operated using the Hurricane i control software provided with the system However if the Hurricane i or the Mai Tai laser are operated using the command language interface you must provide an emission indicator in order to satisfy CDRH regulations e An emission indicator that indicates laser energy is present or can be accessed It can be a power on lamp a computer display that flashes a statement to this effect or an indicat
38. We are always interested in improving our products and manuals and we appreciate all suggestions Thank you From Name Company or Institution Department Address Instrument Model Number Serial Number Problem Suggested Solution s Mail To FAX to Spectra Physics Inc Attention SSL Quality Manager SSL Quality Manager 650 961 7101 1330 Terra Bella Avenue M S 15 50 Post Office Box 7013 Mountain View CA 94039 7013 U S A E mail sales amp splasers com www spectra physics com
39. World Penwell Publishing 10 Tara Blvd 5 Floor Nashua NH 03062 Tel 603 891 0123 Lasers and Optronics Buyer s Guide Lasers and Optronics Gordon Publications 301 Gibraltar Drive P O Box 650 Morris Plains NJ 07950 0650 Tel 973 292 5100 Photonics Spectra Buyer s Guide Photonics Spectra Laurin Publications Berkshire Common PO Box 4949 Pittsfield MA 01202 4949 Tel 413 499 0514 Hurricane i Integrated Ti Sapphire Amplifier System 2 12 Chapter 3 General Description The Hurricane i system includes all of the components necessary to pro duce ultrashort optical pulses to the milli Joule level In addition to the Mai Tai seed laser and Evolution 15 pump laser other internal components include an optical pulse stretcher a regenerative amplifier and an optical pulse compressor Separate system components include the power supplies for the internal pump and seed lasers as well as the Synchronization and Delay Generator SDG II that controls the precise timing required for regenerative amplification The system also includes a notebook computer with Windows based Hurricane i control software pre installed Note User s manuals for the Mai Tai and the Evolution 15 lasers are included with the system and contain detailed descriptions of these systems Note that the version of the Mai Tai used in the Hurricane i is not a tunable laser but is optimized to operate at a single wavelength within a narrow range a
40. Y on the front panel provides the trigger connection to the input Pockels cell OUT 2 DELAY provides the trigger con nection to the output Pockels cell The delay is adjusted by means of the controls on the front panel and the corresponding delay is displayed in nanoseconds above each control OUT 3 DELAY a third delay is provided so that the user can synchronize target or monitor devices to the Hurricane i output pulse It might be used for example to provide timing control for an oscilloscope display The repetition rate of Pockels cell switching and hence the repetition fre quency of the Hurricane i output is dependent on the pre set repetition rate of the input trigger from the Evolution 15 laser The INPUT DIVIDE control provides a means of reducing the Hurricane i repetition rate with out having to adjust the Evolution 15 laser The operation of the SDG II is explained in Chapter 4 The SDG II also contains the control and signals for the Bandwidth Detector BWD The purpose and operation of the BWD is explained in Chapter 4 Hurricane i Integrated Ti Sapphire Amplifier System Hurricane i Control Software Complete control of the Hurricane i including direct control of the Evolu tion 15 pump laser and the Mai Tai seed laser is available through the soft ware interface provided with the system In addition comprehensive status information as well as on board diagnostic information is conveniently dis played for the syst
41. ane i Integrated Ti Sapphire Amplifier System Notes 2 Notes Notes 3 Hurricane i Integrated Ti Sapphire Amplifier System Notes 4 Notes Notes 5 Hurricane i Integrated Ti Sapphire Amplifier System Notes 6 Report Form for Problems and Solutions We have provided this form to encourage you to tell us about any difficul ties you have experienced in using your Spectra Physics instrument or its manual problems that did not require a formal call or letter to our service department but that you feel should be remedied
42. arranty coverage 8 13 Hurricane i Integrated Ti Sapphire Amplifier System Service Centers Benelux Telephone 31 40 265 99 59 France Telephone 33 1 69 18 63 10 Germany and Export Countries Spectra Physics GmbH Guerickeweg 7 D 64291 Darmstadt Telephone 49 06151 708 0 Fax 49 06151 79102 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 Japan West Spectra Physics KK West Regional Office Nishi honmachi Solar Building 3 1 43 Nishi honmachi Nishi ku Osaka 550 0005 Telephone 81 6 4390 6770 Fax 81 6 4390 2760 e mail niwamuro O splasers co p United Kingdom Telephone 44 1442 258100 United States and Export Countries Spectra Physics 1330 Terra Bella Avenue Mountain View CA 94043 Telephone 800 456 2552 Service or 800 SPL LASER Sales or 800 775 5273 Sales or 650 961 2550 Operator Fax 650 964 3584 e mail service O splasers com sales O splasers com Internet www spectra physics com And all European and Middle Eastern countries not included on this list And all non European or Middle Eastern countries not included on this list 8 14 Notes Notes 1 Hurric
43. ating and maintaining the Hurricane i are included in this manual The reader is referred to the respective manuals for descriptions of the Mai Tai and Evolution 15 inter nal laser systems The user manuals for the Mai Tai and Evolution 15 lasers contain instructions for operating these lasers as stand alone systems The oper ating instructions in this Hurricane i manual supersede those in the sep arate user manuals Note in particular that the version of the Mai Tai used in the Hurricane i is not a tunable laser but is optimized to operate at a single wavelength LabWindows is a trademark of National Instruments Corporation Chapter 2 Laser Safety Danger Laser Radiation The Spectra Physics Hurricane i amplifier is a Class IV High Power Laser whose beam is by definition a safety and fire hazard Take pre cautions to prevent accidental exposure to both direct and reflected beams Diffuse as well as specular beam reflections can cause severe eye or skin damage Because the output wavelength is in the infrared the Hurricane i output beam is invisible and therefore especially dangerous This type of infra red radiation passes easily through the cornea of the eye and when Precautions for the Safe Operation of Class IV High Power Lasers Wear protective eyewear at all times selection depends on the wave length and intensity of the radiation the conditions of use and the visual function required Protective ey
44. ation Caution Uu Before the Hurricane i system is installed select a suitable location Ensure that sufficient utilities are available and diagnostic equipment is present The Hurricane i must be located on an optical table with minimum space of about 4 ft x 3 ft 1 2 m x 0 9 m Allow a minimum of 8 in 21 cm of clearance in front of the Hurricane i umbilical panel It is highly recom mended that this table be located in an environment that is free of dust oils and drafts The Hurricane i assembly weighs about 400 lbs 182 kg Be certain the its selected location can provide stable support The Hurricane i is designed to tolerate temperature fluctuations by actively controlling the temperature of each individual module e g Mai Tai Evo lution and regenerative amplifier However the best performance will be achieved if the room temperature does not fluctuate by more than x2 C The Hurricane i should be placed in a location that allows easy access because some adjustments may be required to optimize performance 5 1 Hurricane i Integrated Ti Sapphire Amplifier System Required Utilities The Hurricane i requires the utilities listed below More details are given in the Mai Tai and Evolution user manuals which are shipped with this prod uct US and Japan e two separate B type outlets 110 10 Vac 50 60 Hz 15 A for the power supplies e one separate B type outlet 110 10 Vac 60 Hz 15 A for the chi
45. ault LBO TEMP LBO temp gt preset factory Evolution 15 enters countdown mode to allow temp to Set point return to range before lasing resumes QSW LOW FREQ QSW MODE is set to Ensure that the trigger source is producing TTL EXTERNAL and the pulses at 500 Hz or higher external trigger source drops below 500 Hz QSW VSWR QSW RF connectors on Check connections the Evolution 15 power supply are disconnected QSW TEMP AOM overtemp Verify the chiller is functioning properly water pres sure and reservoir levels are correct and water hoses are not kinked then cycle the keyswitch to clear the fault DRIVER TEMP Diode laser driver FET Check airflow in the Evolution 15 power supply Allow heat sink overtemp the system to run without lasing for at least 10 min utes to cool it down then restart the laser Table 8 1 Fault Indicators Evolution 15 Maintenance and Service LED Indication Corrective Action DIODE TEMP OVER VOLTAGE OVER CURRENT OVER POWER PROT FAULT CHECKSUM ERROR Evolution 15 pump cham ber is overtemp Diode laser is over voltage Diode laser array is over current Diode laser drive FET exceeds the factory set power limit Diode laser drive FET pro tection circuit is activated Communication error for the Evolution 15 Turn off the Evolution 15 power supply Allow the chiller to run for 10 minutes to cool down the power supply verify the chiller temperature is correct then res
46. can in princi ple stretch a short pulse over a longer time Likewise such a device can compress a long pulse into a shorter one by reversing the procedure The phenomenon that delays or advances some wavelengths relative to others is called Group Velocity Dispersion GVD or less formally chirp A pulse is said to have positive GVD or positive chirp when the shorter bluer wavelengths lead the longer redder wavelengths If the bluer light is delayed more than the redder light the pulse has negative chirp CPA starts by lengthening a low energy short duration pulse by as much as 10 by using a combination of dispersive optics to form a pulse stretcher The pulse energy is then increased in the Ti sapphire regenerative ampli fier Finally a compressor recompresses the pulse to close to its original pulse width Figure 3 1 illustrates this process Stretcher Amplifier E Compressor gt MN Se nd A ONO Low Power Reduced Power Amplified High Power Short Pulse Stretched Pulse Stretched Pulse Compressed Pulse pulses not to scale Figure 3 1 Principle of Chirped Pulse Amplification General Description Pulse Stretching and Compression Light incident on a diffraction grating experiences dispersion that is its component wavelengths its spectrum are spatially separated and so its frequency components are also spatially separated The dispersed spectrum can be sent through a combina
47. consult the manual from Ocean Optics provided with the system INTEGRATION PERIOD control sets the length of time in milliseconds over which the spectrometer integrates the selected input signal The inte gration period can be set from 3 to 65 0000 the recommended default value is 100 milliseconds BOXCAR SMOOTHING display sets the number of points over which to average the spectrometer data The range is from 0 to 500 the recom mended default value is 0 COMPRESSED OUTPUT MONITOR W display shows the Hurricane i average output power This is a calibrated measurement REGEN OUTPUT MONITOR W display shows the regenerative amplifier average output power before it is compressed This is a calibrated measure ment PEAK POWER MONITOR ARB display shows an uncalibrated signal that is proportional to the peak power of the Hurricane i pulsed output This display provides feedback to the user while optimizing the Hurricane i out put using the compressor length motor control Note The PEAK POWER MONITOR is only available when the Hurricane i out put is directed out through the front panel Software control of the compressor length is provided on the SDG panel To optimize the compressor while viewing the spectrometer display use the manual control box for the de motor REGEN BUILDUP control reserved Do not change this setting 6 14 SDG Panel Operation BAD Reset Trigger RF Sync Outp Shutter Motor Cont
48. d beam source The beam from this laser is hazardous Refer to the Mai Tai User s Manual for additional safety information The Hurricane i uses a pulsed frequency doubled Nd YLF laser the Evo lution 15 laser as a pump source The beam from this laser is hazardous Refer to the Evolution 15 User s Manual for additional safety information After pressing the ON button on the Evolution 15 display screen a display on the same screen flashes to warn that the Evolution 15 is capable of emit ting laser light There is a 3 second delay between the time the Evolution 15 LED comes on and the time when Evolution 15 can emit laser light During normal operation light from the Evolution 15 is entirely contained within the Hurricane i assembly An emission indicator light on the front of the Hurricane i Figure 2 3 also turns on at this time Whether the Mai Tai seed laser is on or not the Hurricane i is now capable of emitting high power laser light In some circumstances it is possible for a small amount of light from the Mai Tai laser to pass through the Hurricane i and to be emitted from the output port even if other system components are turned off This will not occur if the proper operating procedures are followed Main Emission Output Port Indicator i a Figure 2 3 Hurricane i Emission Indicator Hurricane i Integrated Ti Sapphire Amplifie
49. e Nd YLF Evolution laser Typically an input pulse of only a few nano Joules of energy can be amplified to roughly a milli Joule using a single Ti sapphire rod Normally the amplification of the pulse by the Ti sapphire rod is about 3 or 4 times in a single pass However the multiple passes of the regenerative amplifier can result in an energy amplification greater than 10 at the out put of the compressor When the compressor restores the short duration of the pulse the amplified energy results in correspondingly amplified peak power The Hurricane i Repetition Rate 3 6 The frequency at which the Hurricane i produces amplified pulses is set by the repetition rate of the pulses from the Evolution 15 pump laser This rate 1s preset to either 1 kHz or 5 kHz and should not be changed because this would affect the thermal equilibrium of the Hurricane i However the SDG II allows the Hurricane i repetition rate to be reduced without adjust ing either the Evolution 15 or the Mai Tai seed laser The lowest repetition rate available is about 1 Hz The SDG II itself is described below specifics about operating the SDG II can be found in Chapter 4 General Description The Synchronization and Delay Generator SDG II The Synchronization and Delay Generator or SDG II provides the timing needed to synchronize the Pockels cells to capture pulses in the amplifier and to eject them into the compressor This timing includes synchroniza tion w
50. e OUTPUT SHUTTER The Hurricane i should now be producing output with performance close to that recorded at the time of its last shutdown If this is not the case pro ceed to the section below titled Optimizing Pulsed Output 6 3 Hurricane i Integrated Ti Sapphire Amplifier System Shutdown Procedure Before shutting down record in a system log the output power of the Hurricane i along with the level of the Mai Tai seed laser the Evolution 15 pump laser and the timing parameters of the SGD II 1 If the READ SET control is set to READ Click on STOP on the Regen panel to stop the amplifier from amplifying pulses When the READ SET control is in SET mode clicking on STOP will cause the READ SET control to change to READ mode and clicking STOP again will then turn off the production of amplified pulses Click on STOP on the Evolution panel to turn off the Evolution 15 Turn off the Mai Tai by clicking on STOP on the Mai Tai panel Shut down the Hurricane i control software and turn off the host com puter if appropriate Turn off the SDG II Turn off the key switch and the ac power to the Evolution 15 power supply Note that the heater circuit for the doubling crystal in the Evolution 15 remains on Turn off the key switch and the ac power to the Mai Tai power supply Leave the chiller on unless the system is not going to be used for a long time several days Optimizing Pulsed Output Optimizing Peak Power
51. e it remains horizontally polar ized since the input Pockels cell is on the pulse is flipped 180 each time it traverses the input path leaving its polarization unchanged The pulse is amplified each time it passes through the crystal The pulses that follow behind the selected pulse arrive with the input Pockels cell already turned on and remain vertically polarized as in Case b and are discarded After the selected pulse has passed through the crystal about 20 to 25 times it has reached its optimum amplification The output Pockels cell is now turned on just before the pulse returns to it the precise tim ing is set by the SDG II The pulse now finds the output Pockels cell acting as a quarter wave plate so it is rotated 45 going in and 45 again when reflected back from CM The pulse is thus vertically polarized and is reflected out of the cavity by the horizontal polarizer The Pump Beam Path Optical Layout 11 The vertically polarized amplified pulse is reflected by the polarizer to mirror Ms 12 The pulsed amplified beam is expanded by a telescope comprising a negative and a positive lens not shown and is thus enlarged to reduce pulse power density to protect the compressor optics 13 The expanded beam is directed into the compressor by the polarization rotating periscope PT that changes the vertically polarized light from the amplifier to horizontally polarized light 14 Mg directs the beam into the com
52. ells and allows the Hurricane i to resume amplification Do this after restoring the seed laser spectrum to its proper bandwidth Note that BWD RESET must be selected during the turn on sequence in order for the Hurricane i to function TRIGGER CONTINUOUS switch when set to TRIGGER enables the Hurricane i to fire a single pulse by clicking on the S S button CONTINU OUS is the standard operating mode in which the Hurricane i produces amplified pulses at a selected repetition rate 6 15 Hurricane i Integrated Ti Sapphire Amplifier System 6 16 Note S S button when pressed causes the Hurricane i to fire a single pulse when the TRIGGER mode has been selected RF SYNC button enables the Pockels cells to fire based on the OUT 1 DELAY setting and the next available seed pulse Essentially it provides a way to fire the Hurricane i input Pockels cell based on sync signals from two dif ferent circuits the Evolution 15 Q switch signal and the Mai Tai pulse train REP RATE DIVIDE control reduces the basic Hurricane i pulse repetition rate by an integer value It provides the same function as the INPUT DIVIDE control on the SDG II itself OUTPUT SHUTTER button opens or closes the shutter between the regen erative amplifier and the compressor Closing the shutter blocks the Hurricane i output pulses Note that on some models a system may have had its shutter removed and replaced by a different component SHUTTER OPEN
53. em and its components Detailed instructions for each of the functions available through the Hurricane i software and user interface are provided in Chapter 6 Opera tion Performance Specifications 3 8 Table 3 1 Hurricane i Specifications Energy per Pulse 1 kHz gt 1mJ 5 kHz gt 0 25 mJ Pulse Width lt 130 fs Transform Limit lt 1 5 x transform limit Energy Stability lt 1 RMS Wavelength Preset to one wavelength between 780 nm and 820 nm Transverse Mode TEM lt 1 5 x transform limit Beam Diameter at e points 6 mm nominal Beam Pointing Stability lt 25 prad Contrast Ratio Pre pulse gt 1000 1 Post pulse gt 100 1 Polarization Linear Horizontal Direct Access to Oscillator Output gt 700 mW lt 100 fs at 800 nm Due to our continuous product improvement program specifications may change with out notice A Gaussian pulse shape 0 70 deconvolution factor is used to determine the pulse width FWHM from an autocorrelation signal as measured with a Spectra Physics Model SSA autocor relator Assuming Gaussian pulse shape 4 RMS with near Gaussian distribution 3 Per deg C ambient temperature per hour 9 Specification for pre pulse contrast ratio for 5 kHz operation is gt 500 1 Chapter 4 Controls Indicators and Connections This chapter describes the hardware controls indicators and connections available on the Hurricane i the SGD II controller and the dc motor mot
54. en the Evolution 15 has been started and the 5 second countdown to the start of lasing is underway it turns off when lasing begins EV RAMPING indicator illuminates when the Evolution 15 is started and the diode lasers are performing their ramp up it turns off when the selected diode laser current is achieved EV KEY SWITCH indicator shows the state of the access control key In normal operation this indicator is OFF ON means the key is in the off posi tion FLASHING means the key switch must be recycled to reset a Fault State Q SWITCH MODE control sets the mode of the Evolution 15 Q switch driver Do not change these settings unless instructed to do so by Spectra Physics EXTERNAL indicator this mode is not used for the Hurricane i INTERNAL indicator denotes the normal Hurricane i operating state for the Evolution 15 i e the Q switch trigger source is the internal SAB clock the Q switch repetition rate is set by the software and RF power is being supplied to the AOM transducers to produce Q switched pulsed out put HOLD OFF indicator this mode is used during service CW RF OFF indicator this mode is used during service QSW FREQUENCY KHZ sets the frequency of the internal Q switch trig ger source Note that the Hurricane i is optimized for one frequency rate and this value should not be changed unless instructed to do so by Spectra Physics Hurricane i Integrated Ti Sapphire Amplifier System EV
55. er if the system was properly shut down the Hurricane i shutter should be closed at this time Whenever the Mai Tai laser is on even if other components are off it is possible for a small amount of light to be emitted from the Hurricane i Check the Hurricane i shutter status using the tab that activates the SDG panel on the lower half of the display 7 Click on START on the Evolution control panel Note that unlike the Mai Tai the Evolution 15 does not require its start button to be held down There is a ramp up time of 5 to 10 sec onds before the Evolution 15 begins laser emission 8 Once the Mai Tai and Evolution have ramped up to their appropriate output powers allow 15 to 30 minutes for the system to warm up 9 Startthe Hurricane i amplifier a Click on the SDG panel tab on the lower half of the display b The OUTPUT SHUTTER should be closed c Click on RESET for the BWD interlock If the Mai Tai is properly mode locked the indicators for both BWD1 and BWD2 will be lit Refer to the procedures in Chapter 8 Troubleshooting if the indicators do not come on d Click on START on the REGEN control panel At this point the REG EMISSION indicator should come on and the Hurricane i should begin producing amplified pulses The OUT 1 and OUT 2 indicators should be illuminated on the REGEN panel of the display and on the SDG II controller itself e Move the REGEN interface control switch from SET to READ 10 Open th
56. er AOM exceeds the safe operating temperature for that device DRIVER TEMP indicator illuminates when the diode laser driver FET heatsink becomes overheated due to inadequate airflow to the driver or to a shorted or over current condition DIODE TEMP indicator illuminates when the temperature sensor mounted in the laser pump chamber exceeds the safe operating maximum OVER VOLTAGE indicator illuminates when the voltage required to sup ply the requested current to the diode lasers exceeds the factory set limit Operation OVER CURRENT indicator illuminates when the current requested to drive the diode laser array exceeds the factory set limit OVER POWER indicator illuminates when the internal drive FET exceeds the factory set power limit PROT FAULT indicator illuminates when the internal drive FET protec tion circuit is activated This is a serious internal driver failure that requires repair Warning W Do not operate the Evolution 15 if a PROT FAULT error occurs CHECKSUM ERROR indicator illuminates when a garbled message is detected between the control software and the Evolution 15 Log window displays all the fault conditions fault corrections and their time stamps A new file is created each time the Hurricane i control pro gram is started The file name is a time stamp of the first entry written to it YYYYMMDD txt MAI TAI SET Panel Mode Pump Power Wavelength Set RF Phase Set Modelocker E
57. erting any material into the beam Be certain that any reflections from the inserted object are directed downwards Beam Profile Beam uniformity is best checked by means of visual inspection of the pat tern made on paper containing a fluorescent dye such as a business card This simple method gives excellent results when properly used Refer to the warning above before inserting anything into the beam A poor beam often indicates optical damage or misalignment most likely misalignment of the pump beam Refer to the troubleshooting guide in Chapter 8 if a poor beam is suspected 6 5 Hurricane i Integrated Ti Sapphire Amplifier System Control Software The control software for the Hurricane i is accessed using a Windows shortcut found in the Programs folder of the START menu and also on the desktop The latest version of the software is always available from Spectra Physics This section describes version 1 0 7 Main Screen The three upper panels on the main screen Figure 6 2 provide controls for the Mai Tai seed laser the Evolution 15 pump laser and the regenerative amplifier regen The display and functions in the bottom panel change with each tab selection These panels are described in detail in this chapter Warning The Hurricane i software includes controls intended for use only by authorized Spectra Physics personnel who are trained in their operation These controls are so identified in this chapter do not
58. ewear is available from suppliers listed in the Laser Focus World Lasers and Optronics and Photonics Spectra buyer s guides Consult the ANSI and ACGIH standards listed at the end of this section for guidance Maintain a high ambient light level in the laser operation area so the eye s pupil remains constricted reducing the possibility of damage Avoid looking at the output beam even diffuse reflections are hazardous Avoid wearing jewelry or other objects that may reflect or scatter the beam while using the laser Use an infrared detector or energy detector IR viewer to verify that the laser beam is off before working in front of the laser Operate the laser at the lowest beam intensity possible given the requirements of the application Expand the beam whenever possible to reduce beam power density Avoid blocking the output beam or its reflections with any part of the body Establish a controlled access area for laser operation Limit access to personnel trained in the principles of laser safety Enclose beam paths wherever possible Post prominent warning signs near the laser operating area Figure 2 1 2 1 Hurricane i Integrated Ti Sapphire Amplifier System e Set up experiments so the laser beam is either above or below eye level Set up shields to prevent any unnecessary specular reflections or beams from escaping the laser operation area e Set up a beam dump to capture the laser beam and prevent accidental exposure
59. from the cavity If the output mode is not symmetrical make small adjustments to PM to achieve symmetry Remove the target card and verify that the cavity dumped power agrees with the power achieved at installation for the given pump power If necessary make small adjustments to OUT 2 DELAY to achieve maxi mum cavity dumped power output when measured with the power meter as opposed to viewing the pulse on the scope If the power is still low refer to Troubleshooting Guide on page 2 The seed beam can now be injected and its alignment and timing opti mized for amplified output Hurricane i Integrated Ti Sapphire Amplifier System Customer Service Warranty 8 12 At Spectra Physics we take pride in the durability of our products We place considerable emphasis on controlled manufacturing methods and quality control throughout the manufacturing process Nevertheless even the finest precision instruments will need occasional service We feel our instruments have favorable service records compared to competitive prod ucts and we hope to demonstrate in the long run that we provide excellent service to our customers in two ways First by providing the best equip ment for the money and second by offering service facilities that restore your instrument to working condition as soon as possible Spectra Physics maintains major service centers in the United States Europe and Japan Additionally there are field service offices
60. ght It directs the amplified pulse from the regenerative amplifier into the compressor Tall Stretcher End Mirror is a mirror in the stretcher that is about 95 reflective so that 5 of the beam transmits through and is detected by the bandwidth detector BWD photodetectors located behind the mirror It reflects the beam back onto the gold mirror Vertical Retroreflector is a pair of flat mirrors at right angles that shift the beam upwards about one inch and reflect it back on a parallel path There is a vertical retroreflector in the stretcher and one in the compressor Horizontal Retroreflector is a pair of flat mirrors at right angles in the compressor that shift the beam sideways about two inches and reflect it on a parallel path This assembly is mounted on a translational stage that has a de motor and motion control to adjust the output pulse compression This adjustment allows compensation for variations in the group velocity dispersion GVD that may be experienced by the optical pulse while it is in the amplifier The Mai Tai Beam Bath 7 2 The beam height of the Mai Tai is adjusted to the correct height for the Hurricane i by periscope PTO The beam then passes through the combina tion of the half wave plate 2 and Faraday Isolator This arrangement pre vents feedback from the beam path from reflecting into the Mai Tai which would produce instabilities in its mode locked operation The seed beam is then directed
61. ghtly adjust the height of the stretcher mirror using the micrometer Align the beam into the regenerative amplifier as described in the next section Regenerative Amplifier Optimization 8 8 In the following procedure the regenerative amplifier is initially oper ated as a Q switched laser pumped by the Evolution 15 Block the Mai Tai beam from entering the regenerative amplifier cav ity Turn on the Evolution 15 and allow it to warm up Disable OUT 2 DELAY The regenerative amplifier will begin to operate as a laser Monitor the intracavity radiation using REGEN TRANS PD on the umbilical panel of the Hurricane i see Figure 8 3 and refer to the sec tion Rear Umbilical Panel on page 3 Maintenance and Service Note Use a fast oscilloscope with a micro channel plate screen or a digitizing si oscilloscope with a sampling speed greater than 2 giga samples per sec ond Trigger the oscilloscope externally from the SDG IJ SYNC OUT DELAY Set the time base to 100 or 200 ns div Use a 50 W input imped ance for the photodiode Figure 8 3 Appearance of Q switched Pulse 5 Remove the business card blocking the seed beam The energy of the Mai Tai pulses will now overcome the energy of the spontaneous emis sion in the Ti sapphire rod in the regenerative amplifier so that it now amplifies the seed pulses The intracavity radiation will now appear something like the pattern shown in Figure 8 4 below
62. he Ti sapphire rod to cavity mirror CM 2 Use the IR card or IR viewer to ensure that the beam is clearly visible at CM Make slight adjustments to the input mirror M not the cavity mirrors until you see a beam centered on the aperture in front of the second Pockels cell PC 8 7 Hurricane i Integrated Ti Sapphire Amplifier System If you cannot see the beam 1t will be necessary to check its alignment through the stretcher as follows Rotate the gratings out of the beam path and use the IR card to ensure that the beam is well aligned through the apertures at the entrance to the stretcher and the exit from the compressor Rotate the gratings to their original positions and use an IR viewer to look at the beam pattern on the stretcher grating It should look like the pattern in Figure 8 2 Figure 8 2 Radiation Pattern on Stretcher Grating If the beam pattern does not look like Figure 8 2 it is likely that the wavelength of the Mai Tai laser has changed or the grating is rotated incorrectly In order to return to previous operating conditions verify that the Mai Tai wavelength is the same as it was during prior opera tion then rotate the grating until the pattern is symmetrical on the grat ing as shown in the diagram If you cannot obtain the pattern shown above contact your Spectra Physics representative The output beam from the stretcher should now be picked off by mir ror M It may be necessary to sli
63. hen the leading component of a temporally stretched pulse is forced to take the longer path thereby allowing the trail ing component to catch up In the pulse stretcher shown below the bluer components are forced to take the longer path Creating Negative GVD Redder shorter path Wavelength spatial spreading occurs with red leading the blue because red has a shorter distance to go Pulse wavelengths are spread out here Diffraction Grating 1 Bluer Redder Input Pulse Stretched Output Pulse Figure 3 2 Principle of Pulse Stretching Using Negative GVD Hurricane i Integrated Ti Sapphire Amplifier System The Hurricane i Pulse Stretcher and Compressor The Hurricane i pulse stretcher and compressor make use of some simpli fying modifications A simple but elegant retroreflector assembly reflects the beam back onto a single grating in the stretcher avoiding the need to precisely align two stretcher gratings The beam is also multipassed to achieve the required spectrum spread using less complex optics The same design principal is used in the compressor resulting in only two gratings used instead of four thus simplifying the alignment and mainte nance of the system The compressor uses a horizontal retroreflector while the retroreflector in the stretcher is vertical They are used to flip the red and blue components end for end so that in the compressor the bluer wavelengths are now
64. icking the up down arrows MAI TAI SW REV display identifies the current Mai Tai software revision L MSG display shows the most recent outstanding system message This is provided for use in troubleshooting by a service technician SYSTEM ERROR CODE display shows the most recent outstanding sys tem error This is provided for use in troubleshooting by a service techni cian DIODE CURRENT display shows the actual current reading in Amps for the diode lasers in the Mai Tai pump laser This current is related to pump output power and the current required to maintain a given output level will increase as the diode lasers age DIODE TEMP display shows the diode laser temperature in degrees Cen tigrade Hurricane i Integrated Ti Sapphire Amplifier System SPECT Panel Spectrum Integration Wavelength nm ee ee Regen Buildup Figure 6 7 The Spectrometer Panel The spectrometer panel is used to monitor the bandwidth of the pulses entering either the compressor normal operation or the stretcher service operation Instructions for changing between compressor measurements and stretcher measurements are given in Chapter 4 Refer to SPECTROME TER INPUT OUTPUT SPECTRUM and SEED SPECTRUM in the Back Panel section starting on page 4 7 This screen provides controls for the spectrometer and displays the results of its measurements For detailed information about the operation of the spectrometer
65. ide Panel Mai Tai output port when open provides access to the seed beam This port is compatible with standard beam tubes To use this optional port 1 Close the internal shutters in the Hurricane i the Mai Tai and the Evo lution 15 2 Remove the external cover from the Mai Tai port 3 Install any beam tube s to be used If the normal Hurricane i output ports are not to be used either do not activate the Evolution 15 pump laser or be sure to cover both Hurricane i output ports 5 Open the Mai Tai shutter to allow the seed beam to exit the Mai Tai port A small fraction of the Mai Tai beam may exit the Hurricane i port if it is uncovered and the Hurricane i shutter is open 6 Open the shutters of the Evolution 15 and Hurricane i if the amplified output is to be used simultaneously with the seed beam Alternate output port alternate port for the Hurricane i amplified pulse To use this side port 1 Close the internal shutters in the Hurricane i the Mai Tai and the Evo lution 15 2 Close the front output port 3 Remove the Hurricane i cover The cover interlock on the Hurricane i does not deactivate the Mai Tai laser When the Hurricane i cover is removed and the Mai Tai shutter is open be extremely careful to avoid exposure to the Mai Tai laser beam 4 Remove the M turning mirror and mount used to turn the beam out of the main output port see Figure 7 1 Remove the external cover f
66. igned Optimize the Mai Tai alignment as described on page 8 7 Symptom Regenerative amplifier power is below specification Possible Cause Corrective Action Optics are dusty Clean all optics with particular attention to the pump path and regenerative amplifier optics using the procedure on page 8 6 Optics are damaged Check the optical components in the regenerative amplifier If an optic has been damaged contact your Spectra Physics repre sentative to arrange to have the optic changed It may be pos sible to use an undamaged portion of the optic face and realign the regenerative amplifier as a temporary solution Seed beam is misaligned Optimize the Mai Tai alignment as described on page 8 7 Evolution 15 power is low Optimize the Evolution 15 power according to the Evolution 15 User s Manual Compressor is misaligned Check alignment of the compressor see page 8 10 Timing is incorrect Check settings for OUT 1 DELAY and OUT 2 DELAY on the SDG Il Pump beam is misaligned Optimize the alignment of the pump beam see page 8 11 Maintenance and Service Symptom Pulse has broadened out of specification Possible Cause Corrective Action Compressor delay is not optimized Adjust the compressor motor controller to get the shortest pulse Seed pulses are broadened Check the Mai Tai bandwidth and center wavelength Evolution 15 pump power is low or unsta See troubleshooting guide in Evolution 15 User s Manual b
67. indicator illuminates when the shutter is open This indicator also illuminates when the shutter has been disconnected MOTOR CONTROL controls the translation of the horizontal retroreflector assembly in the compressor to compensate for the small changes in the dis persion that takes place in the amplifier cavity The best compensation will be achieved when the PEAK POWER MONITOR indicates an optimum value FWD forward direction of translation of the retroreflector REV reverse direction of translation of the retroreflector FAST SLOW changes the speed of the translation PEAK POWER MONITOR ARB displays an uncalibrated signal that is proportional to the peak power of the Hurricane i pulsed output This is the same display that appears on the Spectrometer panel and is copied here so that it can be monitored while adjusting the compressor length The PEAK POWER MONITOR is only available when the Hurricane i out put is directed out through the front panel Operation GENERAL SETTINGS Panel EV COM Port Log Sample Time s Log File MT ID Error c HurricaneLog 20021017 000011 txt MT COM Port Y ERR Lablack Error Message MaiT ai Error Message Feature handle creation failed Figure 6 9 The General Settings Panel The following displays provide settings for the communications ports for the computer to control the indicated subsystem EV COM PORT default value is set at the factory MT COM PORT
68. into the stretcher via two alignment mirrors SM and SM The initial Mai Tai output is horizontally polarized but the above combina tion of optics rotates the beam so that it arrives in the stretcher with hori zontal polarization Optical Layout The Stretcher and Compressor Beam Paths Note Although the beam passes from the stretcher into the regenerative amplifier before returning to the compressor the treatment of the beam in both the stretcher and compressor is similar Thus these components are described together first 1 eri PT2 Figure 7 2 Pulse Stretcher and Compressor Beam Sequencing Numbers are used in the following drawing to track the path of the beam as it passes from optic to optic they are not used either to name the optic itself or indicate the position of the beam on the optic Refer to Figure 7 1 for the abbreviations used for the optical components Stretcher 1 The input beam passes through a gap 1 in the vertical retroreflector VRR over the pick off mirror M 2 and onto the stretcher diffraction grating 3 The grating disperses the beam spectrally with the redder wavelengths to the right and the bluer wavelengths to the left and reflects the diverging beam onto the center of the concave gold mirror M 4 The concave gold mirror is angled slightly upward to reflect the beam over the grating onto the tall stretcher end mirror M 5 The beam is then reflec
69. ion 30 fs 6 ps Wellenl nge 700 1000 nm PS Pulsbreite 30 fs 6 ps CE Exposition Dangereuse Un Nicht dem Strahl aussetzen Evitar exponerse j Vanuit dit apertuur wordt zich Aperture Rayonnement laser visible et Austritt von sichtbarer und Atraves de esta apertura se tbare en onzichtbare lasers Label ou invisible est emis par cette oder unsicht barer Laser emite radiacion laser visible y traling geemiteerd 3 ouverture strahlung o invisible Vermijd blootstelling CE Non Rayonnement Laser dan Austritt von sichtbarer und Radiacion laser visible y o Zichtbare en niet zichtbare Interlocked gereux visible et ou invisible oder unsichtbarer Laser invisible al abrir con el seguro laser straling wanneer Label en cas D Ouverture et lorsque strahlung bei ge ffneter anulado Evitar la exposicion geoend vermijd blootsteling 4 la securite est neutralisse Abdeckung und berbr ckter de los ojos o la piel a la radia aan huid of oog aan disecte exposition dangereuse de Sicherheitsschaltung cion ya sea directa o difusa straling of weerkaatsingen 2 8 l oeil ou de la peau au rayon Augen und Hautkontakt mit Producto laser Clase IV nement dirct ou diffus Appar direkter Strahlung oder eil a laser de Classe 4 Streustrahlung vermeiden Laser Klasse IV Laser Safety CE Declaration of Conformity We Spectra Physics Inc Solid State Lasers 1330 Terra Bella Avenue Mountain View CA 94043 United States of America declare under sole
70. ion controller It is important to review the information in this chapter before the system is installed During normal operation the system is controlled through the software interface described in Chapter 6 Operation It is possible however to operate the Hurricane i manually by means of the hardware controls described in this chapter For example they can be used when installing or troubleshooting the system If the system is to be operated manually it is still recommended that the descriptions and procedures in Chapter 6 first be reviewed as that chapter contains important information about the control and behavior of the Hurricane i Hurricane i Assembly External Controls Output End Panel Main Emission Output Port Indicator NT QA E Figure 4 1 Front Panel Main output port the front exit port for the amplified pulse Emission indicator glows to indicate that the Evolution 15 is activated and therefore the Hurricane i may be producing laser pulses Note that the indicator glows when the Evolution 15 is activated even if the internal shutters in the system are closed 4 1 Hurricane i Integrated Ti Sapphire Amplifier System Output Side Panel Danger Laser Radiation 4 2 Optional Mai Tai Alternate Hurricane i Output Port Output Port SI Figure 4 2 Output S
71. ith the Mai Tai and Evolution 15 lasers An error of only two or three nanoseconds in this synchronization will result in extraneous output pulses that can produce measurement errors or damage to optical components As explained above the input Pockels cell confines the selected pulse in the amplifier To ensure that only one pulse at a time is admitted for ampli fication the input Pockels cell is synchronized to the RF signal generated by the Mai Tai mode locker The input Pockels cell then transmits the first stretched seed pulse from the mode locked train that arrives just after a pump pulse has excited the Ti sapphire rod The input Pockels cell contin ues to make this selection after each pump pulse An agjustable delay for firing the input Pockels cell is provided in order to ensure that the cell only fires after the selected pulse has passed completely through it The output Pockels cell ejects the amplified pulse into the compressor Fol lowing synchronization with the input Pockels cell there is an adjustable delay from 0 to 999 ns before activating the output cell to ensure the cap tured pulse is released at optimum amplification This delay allows for the time the pulse takes to complete an integral number of round trips of the amplifier cavity The SDG TI is first triggered by a TTL positive edge pulse provided by the Evolution 15 laser It then produces separate triggers with adjustable delays for both Pockels cells OUT 1 DELA
72. ity Whether a pulse is selected to remain in the cavity is determined by the input Pockels cell When this Pockels cell is off it is transparent to both vertically polarized and horizontally polarized light When a Pockels cell is on it acts together with 4 to rotate the polarization of the beam from horizontal to vertical or vice versa Depending on the state of the input Pockels cell one of three things will now happen Case a if the input Pockels cell is off when the pulse arrives the pulse passes through the cell and is reflected back to the same Pockels cell If this Pockels cell is still off when the pulse returns the pulse is rejected after one round trip through the amplifier Case b if the input Pockels cell is on when the pulse arrives the pulse is not selected and is rejected without passing through the Ti sapphire crys tal Case c the input Pockels cell is off when the pulse arrives but is turned on after the pulse travels through it and before the pulse is reflected back to the same cell The pulse is now selected The pulse makes about 20 round trips in the cavity gaining in amplitude with each pass and is released into the compressor by activating the output Pockels cell Each case is examined in detail below As long as the selected pulse remains horizontally polarized it remains in the cavity Whenever a pulse arrives at the Ti sapphire crystal as verti cally polarized it is ejected Pu
73. later in this chap ter One measure of the quality of pulse selection is given by the contrast ratio the factor by which the amplifier output power exceeds the power in spurious pulses that may be present before or after the main true pulse The value of the contrast ratio is determined by the quality of the 4 wave plates the activation time of the Pockels cells which is a function of their intrinsic birefringence and their drive electronics On Board Spectrometer The Hurricane i includes an on board spectrometer that provides near real time monitoring of the bandwidth at one of two different points within the system In addition to the main reflections or orders from the grating surface gratings also produce dimmer orders that are not used in CPA The system directs these reflections to a spectrometer using an optical fiber A fiber connector jumper on the Hurricane i connector panel allows the bandwidth of the pulses from either the stretcher or the compressor grating to be mon itored In normal operation the spectrometer is used to monitor the bandwidth of the pulses from the compressor grating 1 e the width of the Hurricane i output pulses During maintenance or troubleshooting the optical fiber can be moved to sample the bandwidth of the pulses from the stretcher for use as a diagnostic tool 3 5 Hurricane i Integrated Ti Sapphire Amplifier System Regenerative Amplification Note The regenerati
74. lation of a Well Compressed Pulse 6 5 Figure 6 2 Hurricane i Main Screen 6 6 Figure 6 3 The Evolution System Panel 6 9 Figure 6 4 The EV Fault Panel 2 6 0 bc ee hh nna 6 10 Figure6 5 TheMaiTaiSetPanel 6 11 Figure 6 6 The MaiTailnfoPanel 6 13 Figure 6 7 The Spectrometer Panel 6 14 Figure 6 8 The SDG Panel 6 15 Figure 6 9 The General Settings Panel 6 17 Figure 6 10 The EV Set Panel 6 18 Figure 6 11 the LabJack Panel LL 6 18 Figure 6 12 The Factory Panel 6 18 Figure 7 1 Hurricane i Beam Path 7 1 Figure 7 2 Pulse Stretcher and Compressor Beam Sequencing 7 3 Figure 7 3 Regenerative Amplifier Beam Path pump beam not shown 7 4 Figure 7 4 Pump Beam Path 7 7 Figure 8 1 The EV Fault Panel ooooocooococo hr 8 4 Figure 8 2 Radiation Pattern on Stretcher Grating 8 8 Figure 8 3 Appearance of Q switched Pulse 8 9 Figure 8 4 Intracavity Pulse Train 8 9 Figure 8 5 Intracavity Pulse Train with Correct
75. le Stretcher misalignment is broadening Check the alignment of the stretcher pulses Check the seed beam alignment to make sure it is optimized see page 8 7 Timing is incorrect Check the settings for OUT 1 DELAY and OUT 2 DELAY Symptom Output power is unstable Possible Cause Corrective Action There is power variation in the Evolution See troubleshooting guide in Evolution 15 User s Manual 15 pump There is power variation in the regenera Check the settings for OUT 1 DELAY and OUT 2 DELAY tive amplifier 8 3 Hurricane i Integrated Ti Sapphire Amplifier System EV Fault Software Indicators COVER USER FLOW LBO TEMP QSW LOW FREQ ASW VSVR ASA TEMP DRIVER TEMP DIODE TEMP OVER VOLTAGE OVER CURRENT OVER POWER PROT FAULT CHECKSUM ERROR Figure 8 1 The EV Fault Panel g C HurricanelEvolution 30 Logt Evo 30 log 20021009 txt A number of faults that may occur can be corrected by the user as indi cated in the following table The Hurricane i will need to be restarted after the fault is cleared Table 8 1 Fault Indicators Evolution 15 LED Indication Corrective Action COVER USER Remote interlock on the Check interlocks power supply or a laser head micro switch is tripped FLOW Chiller flow 2 0 GPM Verify that the chiller is functioning properly the water pressure and reservoir levels are correct and the hoses are not kinked then cycle the keyswitch to clear the f
76. like that in Steps 3 and 4 except that now because the polarization of the pulse is rotated another 90 by two passes through 4 it is vertically polarized It is reflected off the surface of the Ti sapphire rod and out of the amplifier cavity back to M Once rejected the pulse passes back through the stretcher and is absorbed by the Faraday isolator Case b the input Pockels cell is already on pulse is rejected 8 As before the incoming vertically polarized pulse reflects off CM and passes through an aperture But this time as it passes through the now active input Pockels cell it is rotated 45 by the cell and another 45 as it passes through 4 becoming horizontally polarized But after reflecting off CM the pulsed beam is rotated another 45 by Na and another 45 by the still active input Pockels cell and it returns to vertical polarization It passes through the aperture reflects off CM reflects off the Ti sapphire surface and is ejected out of the cavity Case c the input Pockels cell is off and is then turned on the pulse is selected 9 10 The soon to be selected pulse comes into the cavity and becomes hor izontally polarized as outlined in Step 3 of Case a This time how ever after the pulse passes back through the inactive Pockels cell and travels toward CM the input Pockels cell is turned on The output Pockels cell remains off for now The pulse remains in the cavity becaus
77. ller e a standard B type 115 Vac socket capable of providing 5 A Europe e two separate F type outlets 220 20 Vac 50 Hz 8 A for the power supplies e one separate F type outlet 220 20 Vac 50 Hz 8 A for the chiller e astandardF type 220 Vac socket capable of providing 3 A Recommended Diagnostic Equipment The following equipment is recommended for day to day operation of the Hurricane i and should be available at the time of installation e a power meter capable of measuring from 10 mW to 20 W average power between 527 nm and 900 nm e g Spectra Physics 407A e a fast CRT analog oscilloscope capable of 300 MHz or better eg Tektronix 2467 7104 or TDS 3052 e a fast photodiode with a 2 ns rise time or better eg Electro Optics Technology Model ET 2000 e R viewer and IR card e anautocorrelator e g Spectra Physics SSA Evolution 15 Power Supply Refer to the Evolution 15 User s Manual for physical specifications and procedures on preparing for installation Mai Tai Power Supply 5 2 Refer to the Mai Tai User s Manual for physical specifications and proce dures on preparing for installation Installation Interconnection Diagram Figure 5 1 and Figure 5 2 are schematics of the signal connections and control connections respectively between components of the Hurricane i system For simplicity water hoses and the more obvious electrical connec tions e g power to the computer are not shown Al
78. low to a parallel path into the Mai Tai It is important to the performance of the seed laser that its cooling water be kept at a constant 21 C The exhausted cooling water from the Mai Tai still has sufficient heat removal capacity to cool the regenerative amplifier rod This design takes the place of the connections described in the manuals for the Mai Tai and Evolution 15 lasers Note that any hose connections that might be present in the Mai Tai umbilical are not used in the Hurricane i and should be set aside left unconnected Regenerative Amplifier A lt Evolution 15 Pump Laser Seed Laser System Chiller Figure 5 3 Flow Diagram for Chiller Water Hurricane i Integrated Ti Sapphire Amplifier System Mechanical Specifications m 132 1 116 2 ni 21 9 55 6 x A inches Dimensions given in cin ale E I Figure 5 4 Outline Drawing Hurricane i 13 0 12 0 gt gt 33 0 F 305 4 S Spectra Physics H VI VI Front Panel Side Panel Figure 5 5 SDG II Outline Drawing Table 5 1 Physical Specifications for Hurricane i Weight 434 lb 197 kg Length 45 8 in 116 2 cm Width 27 8 in 70 5 cm Height 9 6 in 24 4 cm Chapter 6 Eyewear 9 Reguired
79. lse selection is accomplished by the combining the polarization rotating properties of the passive quarter waveplate 4 with the transmission prop erties of the input Pockels cell Pulses at 1 KHz or 5 kHz repetition rate are selected for amplification while the remaining megahertz seed pulses are rejected The synchronized timing for the firing of the Pockels cells is provided by the SDG II Case a the input Pockels cell is off and stays off the pulse is rejected 3 The vertically polarized pulse reflects off CM passes through an aper ture through the inactive input Pockels cell and is rotated 45 as it passes through Lu It reflects off CM and rotates another 45 as it passes through 4 again 4 Now horizontally polarized the pulse passes through the inactive input Pockels cell again through the aperture and again reflects off CM Because it is now horizontally polarized it passes through the Ti sapphire rod and picks up first pass gain 7 5 Hurricane i Integrated Ti Sapphire Amplifier System The pulse continues to CM is reflected through the horizontal polar izer and passes through an aperture and through the inactive output Pockels cell The pulse reflects off CM passes back through the inactive output Pockels cell again goes through the aperture through the horizontal polarizer reflects off CM and passes back through the Ti sapphire rod for second pass gain The next part of the journey is just
80. mplification a technique called Chirped Pulse Amplification CPA circumvents this limitation Windows is a trademark of Microsoft Corporation 3 1 Hurricane i Integrated Ti Sapphire Amplifier System Chirped Pulse Amplification 3 2 A bright beam traveling through a Ti sapphire crystal tends to self focus In this effect intense light modifies the refractive index of a material causing the light to focus and intensify even further potentially damaging the mate rial This tendency makes it necessary to limit the peak power of a pulse in the Ti sapphire gain material to less than 10 GW cn CPA circumvents this obstacle in three steps The first step stretches a very short seed pulse supplied by a mode locked femtosecond laser Stretching the pulse i e increasing its duration reduces its peak power which greatly reduces the probability of damage to the Ti sapphire crystal The second step amplifies the stretched pulse by passing it through the excited Ti sapphire rod A pump laser sends an excitation pulse to the Ti sapphire crystal rod just prior to the arrival of the stretched seed pulse which is then amplified The third step recompresses the stretched ampli fied pulse as close as possible to its original duration The fundamental relationship that exists between laser pulse width and bandwidth is that a very short pulse exhibits a broad bandwidth Therefore a device that can delay certain wavelengths relative to others
81. n the time that the system is first energized and the emis sion of laser light After completing the maintenance and adjustment procedures follow the shut down procedure listed in Chapter 5 Remove the interlock defeats and replace the Hurricane i cover 8 1 Hurricane i Integrated Ti Sapphire Amplifier System Troubleshooting Guide This troubleshooting guide is provided to assist you in isolating some of the problems that might arise for example if performance drops unexpect edly A complete alignment and repair procedure is beyond the scope of this manual This guide should help provide information to your Spectra Physics service representative to assist in obtaining more advanced service 1f required Symptom Emission light comes on but no output Possible Cause Corrective Action Pockels Cells Inactive Check that the LEDs on the SDG II are on for OUT 1 DELAY and OUT 2 DELAY BWD interlock open Check the two LEDs for the BWD on the SDG II If both diodes are on reset the interlock button of the BWD If both diodes are not on check the Mai Tai to make sure the laser is mode locked and the wavelength is centered as speci fied Reset the interlock button of the BWD after restoring Mai Tai operation Mai Tai is not functioning correctly Refer to Mai Tai User s Manual for further instructions Evolution 15 is not functioning correctly Refer to Evolution 15 User s Manual for further instructions Seed beam is misal
82. nable eadi Actual Power Actual Current Wavelength Read RF Phase Read 9850 Modelocker Enabled Figure 6 5 The Mai Tai Set Panel The Hurricane i system provides the option for using the output of the Mai Tai as a separate laser Refer to Chapter 4 Controls Indicators and Connections for instructions on how to access the Mai Tai output The controls and read outs provided on this panel and the following panel MAI TAI INFO can be used to control and monitor the Mai Tai output For a detailed description of the Mai Tai control functions consult the Mai Tai User s Manual provided with the system The following is a brief summary of the Mai Tai control functions the Hurricane i Do not change these settings without first consulting Caution n These parameters are set in the factory to optimize the performance of with your Spectra Physics representative Hurricane i Integrated Ti Sapphire Amplifier System 6 12 MODE switch changes the Mai Tai between power control and current control The default setting is power control the current control mode is for service and troubleshooting Do not change this setting from power con trol unless instructed to do so by an authorized Spectra Physics representa tive MODE READING indicator displays the selected mode PUMP POWER control sets the power level of the pump laser inside the Mai Tai This setting has been set at the factory to optimize the output of
83. ning original warranty period This warranty is in lieu of all other warranties implied or expressed and does not cover incidental or consequential loss Spectra Physics will provide at its expense all parts and labor and one way return shipping of the defective part or instrument if required This warranty does not apply to equipment or components that upon inspection by Spectra Physics discloses to be defective or unworkable because of abuse mishandling misuse alteration negligence improper installation damage in transit or other causes beyond the control of Spec tra Physics Maintenance and Service Return of the Instrument for Repair Contact your nearest Spectra Physics field sales office service center or local distributor for shipping instructions or an on site service appointment You are responsible for one way shipment of the defective part or instru ment to Spectra Physics We encourage you to use the original packing boxes to secure instruments during shipment If shipping boxes have been lost or destroyed we recom mend you order new ones Spectra Physics will only return instruments in Spectra Physics containers Warning Always drain the cooling water from the laser head and or power supply W before shipping Water expands as it freezes and will damage the unit Even during warm spells or summer months freezing may occur at high altitudes or in the cargo hold of aircraft Such damage is excluded from w
84. ocks Danger Laser Radiation Several of the procedures described in this chapter call for the Hurricane i and its component lasers to be operated with the covers removed and the safety interlocks defeated If you are inexperienced at making adjustments to high power infrared laser systems do not proceed with these instruc tions Instead please contact your Spectra Physics representative Shut down the system following the procedure described in Chapter 5 and remove the cover from the Hurricane i Removing the cover activates two microswitches at the corners of the Hurricane i frame that deactivate the diode laser arrays that pump the Evolution 15 With the Evolution 15 deac tivated the regenerative amplifier will also remain off The cover interlock on the Hurricane i does not deactivate the Mai Tai seed laser There are four interlock defeats supplied with the Hurricane i each com prised of a 1 in square aluminum plate and a captive screw Two of these must be screwed into the upper frame of the Hurricane i to depress the cover interlock microswitches and allow the Evolution 15 and the regener ative amplifier to resume lasing when the system is turned back on The remaining two interlock defeats are for use with the Evolution 15 cover itself Removing the Evolution 15 cover is not required by the procedures in this chapter Follow the procedure in Chapter 5 for starting the system Recall that there is a delay betwee
85. ontents Prefacio atada iaa iii Regulatory Specifications V CE Electrical Equipment Requirements V Environmental Specifications V FCC Reg lations uz irme Ra Eu AT IONE fe EGG KE RE SEAN BENA a V Warning Conventions KN NNN kaum rx xxxn ra xi Standard Units cis ge cese uos usua Rx kan k ee ee a xiii Abbreviations cuicos NEE EE A RR RR RR Ead x XV Unpackingandinspection xvi Unpacking Your Laser cio RR A a dE xvii System COMPONENTS ici sivet rate A A AAA AAA xvii ACCESSO LEE EE EE xviii Chapter 1 Introduction 0 AAA e E NAE RR Sae ua t UR x 1 1 Chapter 2 Laser Satelite ia Pa 2 1 Precautions for the Safe Operation of Class IV High Power Lasers 2 1 Mode Locked Laser lh mr 2 3 Pump Laser i 12 raa epe DER DR RUE a E pria p m rece ud den Nera e wa 2 3 Safety Devices caida e e lem etat e Geen EE ox d eate on 2 3 Maximum Emission Levels annzanaananann 2 5 CDRH Requirements for Operating the Mai Tai Using the RS 232 Interface and Command Language 2 5 Maintenance Necessary to Keep this Laser Product in Compliance with CDRH Regulations e 2 6 CE CDRH Radiation Control Drawings
86. or error Text describes exceptional circumstances or makes a special refer ence Do not touch Appropriate laser safety eyewear should be worn during this opera tion Refer to the manual before operating or using this device xi Standard Units The following units abbreviations and prefixes are used in this Spectra Physics manual Quantity Unit Abbreviation mass kilogram kg length meter time second S frequency hertz Hz force newton N energy joule J power watt W electric current ampere A electric charge coulomb C electric potential volt V resistance ohm Q inductance henry H magnetic flux weber Wb magnetic flux density tesla T luminous intensity candela cd temperature celcius C pressure pascal Pa capacitance farad F angle radian rad Prefixes tera 10 T deci 10 d nano 10 n giga 10 G centi 10 c pico 107 p mega 10 M mill 10 m femto 10 f kilo 10 k micro 109 up atto 10 a xiii Abbreviations The following abbreviations are used in this manual AC AOM AR C CDRH CPA CW DC E O F fs GVD HR IR OC ps RF SCFH SPM TEM Ti sapphire A alternating current acousto optic modulator antireflection Centigrade Center of Devices and Radiological Health Chirped Pulse Amplification continuous wave direct current electro optic Fahrenheit femtosecond or 10 second group velocity dispersion high reflector infrared output coupler
87. or on the control equip ment for this purpose It need not be marked as an emission indicator so long as its function is obvious Its presence is required on any con trol panel that affects laser output including the computer display panel 2 5 Hurricane i Integrated Ti Sapphire Amplifier System Maintenance Necessary to Keep this Laser Product in Compliance with CDRH Regulations This laser product complies with Title 21 of the United States Code of Fed eral Regulations Chapter 1 sub chapter J parts 1040 10 and 1040 11 as applicable To maintain compliance with these regulations once a year or whenever the product has been subjected to adverse environmental condi tions e g fire flood mechanical shock spilled solvent etc check to see that all features of the product identified on the CE CDRH Radiation Con trol Drawing found later in this chapter function properly Also make sure that all warning labels remain firmly attached Verify that removing the auxiliary interlock connector on the Mai Tai power supply prevents laser operation see the Mai Tai user s manual 1 Verify the laser can only be turned on when the keyswitch of both power supplies are in the ON position and that the keys can only be removed when the switches are in the OFF position 2 Verify the emission indicator provides a visible signal when the laser emits accessible laser radiation that exceeds the accessible emission limits for Class L
88. pment needed to provide the electrical service listed under Service Requirements at the end of Chapter 3 please refer to specification EN 309 Plug Outlet and Socket Couplers for Indus trial Uses listed in the official Journal of the European Communities Environmental Specifications FCC Regulations The environmental conditions under which the laser system will function are listed below Indoor use Altitude up to 2000 m Temperatures 18 C to 35 C Maximum relative humidity 80 non condensing for temperatures up to 31 C Mains supply voltage do not exceed 10 of the nominal voltage Insulation category II Pollution degree 2 This equipment has been tested and found to comply with the limits for a Class A digital device pursuant to Part 15 of the FCC Rules These limits are designed to provide reasonable protection against harmful interference when the equipment is operated in a commercial environment This equip ment generates uses and can radiate radio frequency energy and if not installed and used in accordance with the instruction manual may cause harmful interference to radio communications Operation of this equipment in a residential area is likely to cause harmful interference in which case the user will be required to correct the interference at his own expense Modifications to the laser system not expressly approved by Spectra Physics could void your right to operate the equipment Table of C
89. pressor chamber see Figure 7 1 CM1 Beam Dump Evolution 15 Pump Laser Figure 7 4 Pump Beam Path The green 527 nm light from the Q switched Nd YLF Evolution 15 laser is horizontally polarized so that it can enter into and be absorbed by the Ti sapphire rod Roughly 80 of the pump beam is absorbed by the rod The pump beam traces a path through the following optical elements The beam is translated to the correct height for the Hurricane i chassis by a periscope made up of mirrors PM and PM Lenses PL and PL comprise a telescope that enlarges the pulsed beam from the Evolution 15 by a factor of 4 so that it can be better focused into the Ti sapphire rod The pump beam should be centered on pump lens PL3 7 7 Hurricane i Integrated Ti Sapphire Amplifier System PL focuses the pump beam into the Ti sapphire rod and the beam is directed to the rod by turning mirror PM The fraction of the high power pump beam that is not absorbed by the Ti sapphire rod transmits through the rod onto CM CM does not reflect a significant amount of 527 nm light and the pump beam passes through it and is absorbed by the beam dump behind it Chapter 8 Danger Laser Radiation Maintenance and Service Exceptional care must be taken when operating the Hurricane i with the covers removed The output beam can be very dangerous Protective eyewear at must be worn to protect from all laser wavelengths Defeating the Cover Interl
90. pulse passes through The voltage for the Pockels cells is provided by two high voltage sup plies in the SDG II 1 KHz systems or by a separate power supply 5 kHz systems The actual drivers for the Pockels cells are in the Hurricane i head Properly aligning a Pockels cell even as a passive transmissive optic 1 e with no applied voltage 1s important for it to function properly Likewise the applied voltage must be calibrated to achieve the precise degree of polarization rotation required The input Pockels cell is paired with a passive Y4 waveplate and the optical path is designed so that the beam makes a double pass through this combi General Description nation A double pass of the beam through a 44 waveplate rotates the polar ization of the pulsed beam by 90 from horizontal to vertical or vice versa When the cell is off the double pass through the passive 4 waveplate flips the beam polarization when the cell is on the beam experiences a double pass through two 4 waveplates leaving its polarization unchanged Chapter 4 describes how the input Pockels cell combines with the optics in the amplifier to select a pulse for amplification The output Pockels cell works in conjunction with the polarizer in the amplifier cavity to output an amplified pulse at a time determined by the SDG II Details on how the timing is set for ejecting an amplified pulse are provided in The Synchronization and Delay Generator
91. r BNC connects to the OUT 2 DELAY connector on the front of the SDG II for triggering the output Pockels cell IN connector the input water connection for the chiller OUT connector the output water connection for the chiller DC MOTOR input connector BNC connects to the motor controller provided with the system This provides control of the micrometer motor that sets the length of the compressor Refer to Motor Controller below REGEN OUT PD BNC provides connection to the detector used to mon itor the amplified pulse exiting the regenerative amplifier REGEN TRANS PD BNC provides connection to the detector used to monitor the amplified pulse train in the regenerative amplifier cavity BUILDUP IN connector reserved labeled D A IN on some units SPECTROMETER connector USB connects the output of the spectro meter to the control computer 4 3 Hurricane i Integrated Ti Sapphire Amplifier System OUTPUT SHUTTER connector USB provides computer control of the Hurricane i shutter located in the compressor SPECTROMETER INPUT fiber optic connector SMA connects via a fiber optic jumper cable to either the OUTPUT SPECTRUM connector to monitor the output of the Hurricane i or to the SEED SPECTRUM connec tor to monitor the output of the Mai Tai seed laser OUTPUT SPECTRUM fiber optic connector SMA links the spectro meter to the detector for monitoring the reflection from the compressor
92. r System Shutter Interlock Keyswitches The internal electromechanical shutters are controlled via the control soft ware or via the RS 232 interface The interlock fault and fail safe modes are the closed position There are three external output ports for laser emission two for the Hurricane i output and one optional port for the Mai Tai laser output Dur ing normal operation only one Hurricane i output port is used The other port should be sealed Mai Tai laser output is available as an option for the user Note that the Mai Tai Hurricane i and Evolution 15 each contain internal shutters that are individually computer controlled There is no one control that opens or closes all of them at the same time Refer to the respective user s manuals included with the Hurricane i system for more information about these shutters Two keyswitches provide interlock safety by preventing unauthorized per sonnel from using the Hurricane i system when the keys are turned to the off position and the keys are removed Turning a key to the on position closes the interlock and allows the diode lasers in the power supplies to be energized 1f the ac power switches are also on These keyswitches are on the Mai Tai and the Evolution 15 power supplies Refer to the respective user s manuals included with the Hurricane i sys tem for more information on these keyswitches Switches and Power Indicators Switches on the Mai Tai and the Evol
93. r the 1 KHz or the 5 kHz amplifier rate The SDG II synchronizes the Mai Tai pulses with the Evolu tion pump laser that is it captures the next seed pulse while the laser rod is still excited by the pump pulse It does this by providing an adjustable delay in nanoseconds that is used to set the input Pockels cell of the amplifier to capture the pulse The second adjustable delay controls the output Pockels cell to eject the pulse into the compressor after it has been amplified The SDG II allows the output repetition rate to be reduced from its pre set value by dividing the input synchronization signal from the Evolution pump laser by integers The third adjustable delay provides a trigger for laboratory equipment such as the horizontal sweep of a high speed oscilloscope The SDG II also contains high voltage supplies to power the drivers for the Pockels cells in systems that operate at 1 KHz The drivers themselves are located in the Hurricane i below the regenerative amplifier cavity Controls Indicators and Connections Front Panel TRIGGER FREQUENCY kHz BWD OUT 1 DELAY ns OUT 2 DELAY ns SYNC OUT DELAY na ro RESET 1 B a BB comnnuous B UN error Msc sHor SMC ENABLE MODE MAN TRIG 8 El 8 Figure 4 4 SDG II Front Panel TRIGGER FREQUENCY display shows the output frequency set for the Hurricane i in kHz INPUT DIVIDE control allows the output frequency of the SDG II to be reduced by integer divisors e g 2
94. r warranty repair The last part of the manual covers service and includes a replacement parts list and a list of world wide Spectra Physics service centers you can call if you need help This product has been tested and found to conform to Directive 89 336 EEC for electromagnetic Compatibility Class A compliance was demon strated for EN 50081 2 1993 Emissions and EN 50082 1 1992 Immu nity as listed in the official Journal of the European Communities It also meets the intent of Directive 73 23 EEC for Low Voltage Class A com pliance was demonstrated for EN 61010 1 1993 Safety Requirements for Electrical Equipment for Measurement Control and Laboratory use and EN 60825 1 1992 Radiation Safety for Laser Products Refer to the CE Declaration of Conformity statements in Chapter 2 This product conforms to the requirements of 21 CFR 1040 10 CDRH and are compliant to Underwriters Laboratory UL1950 and are listed as ULR for recognized components This equipment has been designed and tested to comply with the limits for a Class A digital device pursuant to Part 15 of the FCC Rules If you encounter any difficulty with the content or style of this manual please let us know The last page is a form to aid in bringing such problems to our attention Thank you for your purchase of Spectra Physics instruments Regulatory Specifications CE Electrical Equipment Requirements For information regarding the equi
95. rol emm Shutter Opel FAST Continuous 6 BAD Override DC Interlock por CEN Rep Rate Divide SLOW Peak Power Monitor arb 10 00 Figure 6 8 The SDG Panel Warning W The READ SET control on the Regen panel of the Main screen determines whether the values for SDG TI functions are set by software or by the hard ware controls on the SDG II unit itself Refer to the description of the func tions of the Regen panel earlier in this chapter for a explanation of the interaction of the software and the SGD II BWD1 indicator illuminates when photodiode PD 1 used for the long wavelength end of the seed pulse spectrum is functioning and detecting a pulse BWD2 indicator illuminates when photodiode PD 2 used for the short wavelength end of the seed pulse spectrum is functioning and detecting a pulse When the seed laser is stable and properly mode locked BWD1 and BWD2 together permit the SDG TI to function normally When either BWD1 or BWD2 senses a lack of signal a relay will disable the Pockels cells When this happens no pulses are selected for amplification thus protecting the optical components BWD OVERRIDE indicator indicates that the BWD has been disabled thereby allowing the amplifier to function regardless of spectrum spread Disabling the BWD can cause permanent damage to the Hurricane i DC INTERLOCK indicator reserved for future use BWD RESET button resets the relay for the Pockels c
96. rom the side output port Install any beam tube s to be used Replace the Hurricane i cover Open the internal shutters of the Evolution 15 the Mai Tai and the Hurricane i to resume operation MNA Controls Indicators and Connections Rear Umbilical Panel Note Mai Tai Umbilical Attachment Port Figure 4 3 Umbilical Panel Hurricane i Allow a minimum of 8 in clearance in front of the umbilical panel to allow the proper bend radius for the Mai Tai umbilical This is a require ment for the fiber optic cables within the umbilical that supply optical power from the Mai Tai power supply to the seed laser Note that the Evolution 15 umbilical cable passes through the opening in this panel and is hard wired to the internal Evolution 15 laser head HIGH VOLTAGE HSD 1 connector MHV connects by means of a high voltage cable to the 1 6 kV dc H V 1 output connector on the back of the SDG II 1 kHz systems or to the auxiliary power supply 5 kHz systems for driving the input Pockels cell HIGH VOLTAGE HSD 2 connector MHV connects by means of a high voltage cable to the 1 6 kVdc H V 2 output connector on the back of the SDG II 1 kHz systems or to the auxiliary power supply 5 kHz systems for driving the output Pockels cell HSD 1 TRIG connector BNC connects to the OUT 1 DELAY connector on the front of the SDG LI for triggering the input Pockels cell HSD 2 TRIG connecto
97. rotecting the optical components Controls Indicators and Connections The following indicators and connectors for the BWD are on the SDG II PD 1 PD 2 indicators front panel when both lamps are on they indi cate that the stretcher is spreading the seed pulse spectrum properly on the tall stretcher end mirror PD 1 represents the red end of the spectrum PD 2 represents the blue end If a lamp is off the corresponding photo detector is receiving a signal below threshold RESET button front panel when the underlying problem is resolved and both lamps are on pressing this button resets the relay and restores the outputs from OUT 1 DELAY and OUT 2 DELAY BWD connector front panel this 4 pin 12 mm connector connects to the BWD photodiodes via the 9 pin D sub connector on the Hurricane i umbilical panel BWD ON switch back panel this switch when in the down position disables the BWD and allows the amplifier to function regardless of spec trum spread or the detection of a BWD signal Use this switch for trouble shooting purposes only Warning The BWD is not a fail safe device Its purpose is to protect against the W restriction of the stretched pulse spectrum It cannot detect instabilities in the seed spectrum itself that result from poor modelocking Optical damage to the system can result from such instabilities Disabling the BWD can result in permanent damage to the Hurricane i Back Panel ENABLE MIC
98. round 800 nm Ti Sapphire Laser Theory The Ti titanium ion is responsible for the laser action of Ti sapphire Ti sapphire is produced by introducing Ti O into a host crystal of AL O where Ti ions substitute for a small percentage of the Al ions The elec tronic ground state of the Ti ion interacts with the host crystal and is split by lattice vibrations into a pair of very broad levels Transitions occur from the vibrational levels of the upper electronic state excited by a blue or green pump laser to the lower vibrational levels of the ground state The possibility of these transitions between broad energy levels results is a wide range of wavelengths over which laser emission may occur A Ti sap phire laser can produce light from less than 700 nm to over I um in wavelength the broadest tuning range of any single laser medium This extremely broad tuning range or bandwidth while not directly utilized in the Hurricane i system has important consequences for producing ultra short pulses as described in the section that follows The Ti sapphire crystal exhibits high resistance to thermally induced stress This resistance allows it to be optically pumped at relatively high average powers without danger of fracture However it cannot handle the high peak powers that would result from seeding the amplifier directly with femtosec ond pulses Stretching the pulse prior to amplification and recompressing it following a
99. side from being dangerous improper application of these procedures may result in damage to the Hurricane i that will not be covered by your warranty If you have any question about your ability to follow these procedures please do not hesitate to contact your Spectra Physics repre sentative Pulse Train Stability The stability of the mode locked pulse train must be kept optimized to ensure the stability of the regenerative amplifier Please refer to the Mai Tai User s Manual The duration of the input pulse is particularly important If the pulse dura tion is too long pulse stretching will be insufficient and optical damage to the Hurricane i could occur The pulse duration and spectrum should be kept within specification Seed Beam Alignment Refer to Chapter 7 for diagrams of the Hurricane i optical layout Verify the Evolution 15 laser is off Turn on the Mai Tai if necessary and allow it to warm up thoroughly 1 Use the IR card or IR viewer to check the alignment of the Mai Tai beam into the regenerative amplifier It is possible that the beam has drifted slightly since the Hurricane i was last operated The beam is injected into the regenerative amplifier after first reflecting off one face of the Ti sapphire rod The beam should be aligned so that it is centered on the aperture in front of the first Pockels cell PC The beam should pass through PC and reflect back down the resonator through all the optics including t
100. so not shown is the fiber optic jumper that connects the spectrometer to either the input from the stretcher or the compressor Refer to the descrip tion of the rear umbilical panel of the Hurricane i assembly in Chapter 4 for information about this jumper Hurricane i Mai Tai Seed Laser Evolution 15 Power Supply DC MOTOR HSD 2 TRIG1 SYNC OUT motlon controller safety interlock HSD 1 TRIG1 TRIGGER IN OUT 2 DELAY OUT 1 DELAY Connected in 1 kHz systems only 5 kHz systems use a separate HV power supply Figure 5 1 Interconnect Diagram 1 kHz Hurricane i 5 3 Hurricane i Integrated Ti Sapphire Amplifier System Evolution 15 Power Supply PORT 1 Hurricane i PORT 2 USB Serial Converter PORT 3 di 3 lu 3 ur O E Mai Tai m D Power Supply 5 USB Hub external power D N Dv m Control SDG II Computer Figure 5 2 Hurricane i Control Diagram 5 4 Chiller Installation The Ti sapphire amplifier rod absorbs heat from the Evolution 15 pump beam and from its own amplified circulating beam and must be cooled to avoid damage The water flow to the amplifier is in series downstream from the Mai Tai as shown in Figure 5 3 Water from the chiller is connected to the IN port of the Hurricane i connection panel and goes directly to the Evolution 15 Before cooling the pump laser however a tee divides the cooling water f
101. tart the laser running it at a lower diode laser drive current Check the umbilical connection and cycle the power on the power supply to clear the fault Lower the current drive setting then cycle the power on the power supply to clear the fault Reduce the diode laser drive current then cycle the power on the power supply to clear the fault Shut down the Hurricane i system and contact Spec tra Physics Do not operate the Evolution 15 if a PROT FAULT error occurs If infrequent these can be ignored If they occur fre quently check the RS 232 cable connections 8 5 Hurricane i Integrated Ti Sapphire Amplifier System Cleaning the Optics Danger Laser Radiation Caution n Do not attempt to clean the optics while laser light is circulating in the Hurricane i Shutter the Mai Tai beam shutter the Evolution 15 beam if the cover interlocks have been defeated The following materials are required e Reagent grade methanol or acetone e Lens tissues e Hemostat surgical pliers e Eyedropper The gold mirror and the gratings cannot be cleaned other than by blow ing dust from their surfaces with dry nitrogen Do not allow anything to touch the surfaces of these optics or they may be permanently damaged Optics should be carefully cleaned with soft optical tissue and reagent grade methanol or acetone as follows Wash your hands to remove all dirt and oil residues Wear finger cots at all times
102. ted back over the grating again to the concave mirror 6 and returned to the grating 7 The grating reflects the beam toward the bottom of the vertical retrore flector 8 The path of the redder wavelengths is longer than that of the bluer wavelengths and therefore lags behind of the bluer wave lengths The vertical retroreflector shifts the beam upwards and reflects it back to the top of the grating 9 passing through the stretcher one more time 10 11 12 Because the beam hits low on the concave mirror it is reflected to the bottom of the grating 13 and as it leaves the grating it is low enough to be picked off by M 14 and sent out of the stretcher 7 3 Hurricane i Integrated Ti Sapphire Amplifier System Compressor After amplification in the Ti sapphire cavity the pulsed beam enters the compressor Continue to refer to Figure 7 1 for the symbols for the optical components 1 The polarization rotating periscope PT changes the beam to horizon tally polarized and directs 1t into the compressor see Figure 7 3 The beam is directed to the compressor turning mirror Mg 1 The beam reflects onto the right side of the compressor grating 2 3 The grating spreads the temporally broadened beam with the redder wavelengths on the right and the bluer wavelengths on the left and reflects the beam towards the horizontal retroreflector 3 4 The horizontal retroreflector shifts the beam over about two inches 4
103. ted the corresponding LED MAN TRIG control when the selected MODE is SINGLE SHOT pressing this button causes the three output triggers to fire a single pulse ENABLE controls these three buttons turn on and off the three adjustable output trigger signals If a signal is enabled ON its corresponding LED is on When set to OFF that output is deactivated and the other outputs remain active Hurricane i Integrated Ti Sapphire Amplifier System Bandwidth Detector OUT 1 DELAY display control and connector the display shows the selected delay from 0 to 1275 ns between the time the Q switch in the Evolution laser is fired and the time the input Pockels cell is turned on to capture the current seed pulse in the Hurricane i amplifier The output is a 1 5 us positive TTL pulse The control knob adjusts the delay in 250 ps increments or 10 ns incre ments if the knob is pushed in during adjustment The BNC connector con nects to the Hurricane i HSD 1 TRIG connector and provides a low voltage sync signal for the high voltage driver that turns on the input Pockels cell to capture the current seed pulse OUT 2 DELAY display control and connector the display shows the selected delay from 0 to 1275 ns when the output Pockels cell is turned on to eject the amplified pulse into the compressor The output is a 1 5 us pos itive TTL pulse The control knob works the same way as the one for OUT 1 DELAY The BNC connector attaches to the
104. ter provided MED SLOW RANGE RAPID OG Low High Figure 4 7 Motion Controller SLOW MED HIGH control sets the coarse speed range at which the motor micrometer moves when either the or buttons are pushed SLOW RANGE control provides either LOW or HIGH fine control of the SLOW speed of the motor micrometer button moves the compressor retro reflector to lengthen the beam path in the compressor button moves the compressor retro reflector to shorten the beam path in the compressor Hurricane i Integrated Ti Sapphire Amplifier System 4 10 Chapter 5 Warning W Installation Installation of the Hurricane i system must be performed by an authorized service representative This service is included as part of your purchase agreement Please call to arrange an appointment The customer will be held responsible for any damage to the equipment that results from unau thorized installation and such action may also void the warranty Please read this chapter thoroughly and become familiar with the proce dures and safety precautions before the system is installed You may also unpack the laser and locate it in the area where it will be used Refer to Unpacking and Inspection at the beginning of this manual Do not attempt to install the laser yourself Unauthorized installation will void the warranty Requirements for Installation Loc
105. tion of optics to direct the different frequen cies in different directions so that one end of the frequency range travels over a longer path than the other frequencies that are present in the light beam If the light beam is pulsed the result of this dispersive design is to lengthen the duration of the pulse and reduce its peak power A prism which is a simpler optic than a diffraction grating can also be used for these purposes However because the pulse passes through a prism negative GVD is introduced by the glass or quartz of the prism body that is blue frequencies are delayed relative to the red frequencies each time the pulse passes through the prism Gratings are often a better choice for CPA because they simplify the dispersion compensation of the pulse The grating and routing mirrors in the stretcher are configured so that the bluer components of the spectrum travel a longer path than the redder com ponents causing the redder components to exit the stretcher first In the compressor the spatially spread beam is flipped so that the redder compo nents have to take the long path allowing the bluer components to catch up This compresses the pulse back close to its original width Figure 3 2 shows a simplified pulse stretcher A short pulse is spectrally spread and then by making one end of the spread pulse travel farther than the other end the pulse is temporally broadened The same optical compo nents act as a compressor w
106. tional Standards Institute ANSI 11 West 42 Street New York NY 10036 Tel 212 642 4900 Occupational Safety and Health Administration Publication 8 1 7 U S Department of Labor 200 Constitution Avenue N W Room N3647 Washington DC 20210 Tel 202 693 1999 A Guide for Control of Laser Hazards 4th Edition Publication 0165 American Conference of Governmental and Industrial Hygienists ACGIH 1330 Kemper Meadow Drive Cincinnati OH 45240 Tel 513 742 2020 Internet www acgih org home htm Laser Institute of America 13501 Ingenuity Drive Suite 128 Orlando FL 32826 Tel 800 345 2737 Internet www laserinstitute org Compliance Engineering 70 Codman Hill Road Boxborough MA 01719 Tel 978 635 8580 International Electrotechnical Commission Journal of the European Communities EN60825 1 TR3 Ed 1 0 Laser Safety Measurement and Instrumentation IEC 309 Plug Outlet and Socket Coupler for Industrial Uses Tel 41 22 919 0211 Fax 41 22 919 0300 Internet http ftp 1ec c h Cenelec European Committee for Electrotechnical Standardization Central Secretariat rue de Stassart 35 B 1050 Brussels Document Center 1504 Industrial Way Unit 9 Belmont CA 94002 4044 Tel 415 591 7600 Laser Safety Equipment and Training Laser Safety Guide Laser Institute of America 12424 Research Parkway Suite 125 Orlando FL 32826 Tel 407 380 1553 Laser Focus World Buyer s Guide Laser Focus
107. upply will take about 15 to 30 minutes to warm up com pletely If the Hurricane i control computer is not turned on do so now but do not start the Hurricane i control program yet When the power supply warm up is complete the LCD screen will switch to a display of status codes 3 Start the Evolution 15 power supply a Verify that the LBO heater control temperature is at the proper fac tory set temperature b Turn on power supply ac switch c Turn on the power supply key switch Turn on the power to the SDG II 5 Start the Hurricane i control program Once the Main Screen is avail able the procedure to start the Hurricane i system will proceed from the leftmost panel Mai Tai to the rightmost Regen 6 Start the Mai Tai seed laser a Click on and hold down the START button for about 3 seconds until the EMISSION indicator turns on The laser is on when the EMIS SION indicator is on Initial power however will be very low as indicated on the display b After the Mai Tai has achieved maximum output power verify the MODELOCKED indicator is on If it is not on refer to the proce dures in Chapter 8 Troubleshooting to investigate the status of the Mai Tai laser Danger Laser Radiation Operation c Click on OPEN SHUTTER When the SHUTTER indicator turns on the shutter will open and emission from the Mai Tai will be present in the Hurricane i cavity For systems with a Hurricane i shutt
108. use them File Edit Operate Tools Window Help D STOP Exit Control Program Evolution Evolution Regen Start Emission Emission Interlock p Interlock Out 2 nm Ps Current Monitor 4 Delay1 ns Delay2 ns Delay3 ns JEE EVOLUTION STATUS Q SWITCH MODE SW FREQUENCY kHz ELAPSED TIME EV STOP EXTERNAL ho SEH INTERNAL EV COUNT DOWN HOLD OFF EV RAMPING so CW RF OFF QSW PULSE WIDTH uS EV KEY SWITCH Figure 6 2 Hurricane i Main Screen Windows is a registered trademark of Microsoft Corporation Mai Tai Panel Evolution Panel Note Operation START button starts the seed laser This button must be held down for about 3 seconds to activate the Mai Tai STOP button stops operation of the seed laser and closes the Mai Tai shutter MAI TAI EMISSION indicator illuminates when the seed laser output is available although there may be no emission if the Mai Tai shutter is closed INTERLOCK is reserved for future use OPEN SHUTTER button opens or closes the internal shutter in the Mai Tai SHUTTER indicator illuminates when the Mai Tai shutter is open POWER indicator displays output power in Watts bar indicator and as a relative value digital display MODELOCKED indicator indicates that the Mai Tai is producing mode locked seed pulses START button starts the Evolution 15 pump laser When START is selected the diode laser arra
109. ution 15 power supplies provide ac power to the system and associated LEDs when on indicate that ac power is applied to the system control circuits Refer to the respective user s man uals included with the Hurricane i system for more information on these components Cover Safety Interlocks Danger Laser Radiation 2 4 The Hurricane i is not intended for routine operation with the covers removed The cover safety interlock is activated whenever the cover is opened and terminates Hurricane i laser action by switching off the Evolu tion 15 The Hurricane i should not be operated unless this interlock pro tection is available However the interlock can be overridden for maintenance or service needs Chapter 8 Maintenance and Troubleshoot ing describes the procedure for defeating the interlock The cover interlock on the Hurricane i does not deactivate the Mai Tai laser When the Hurricane i cover is removed and the Mai Tai is on be extremely careful to avoid exposure to the laser beams or its reflections Laser Safety Both the Mai Tai and the Evolution 15 lasers are sealed at the factory to prevent contamination Opening these systems will void your warranty The power supplies are is not intended to be operated with the covers removed Therefore there are no cover interlocks Non interlock warning labels are attached to the power supplies Refer to the Mai Tai and the Evo lution 15 user s manuals for more information
110. ve amplifier can be thought of as a Q switched cavity dumped Ti sapphire laser that is operated as an amplifier Pulses from the seed laser that have an energy exceeding the energy of the spontaneous emission in the amplifier are injected into the amplifier cavity Instead of amplifying the spontaneous emission that normally happens in a laser the stimulated emission of the laser rod in a regenerative amplifier amplifies the seed laser pulses At times when aligning the system the Hurricane i is operated as a laser rather than a regenerative amplifier Regenerative amplifiers seeded by low energy laser pulses are an efficient means of generating very high peak power pulses After leaving the stretcher the Mai Tai mode locked pulses selected for amplification are confined in the amplifier cavity using the polarization discrimination tech niques described above Pulses not selected are diverted from the cavity and dumped internally The frequency rate of mode locked pulses from the seed laser is about 80 MHz Selecting pulses at kilohertz repetition rates for amplification enables the gain in the amplifier to be concentrated on fewer pulses After achieving the appropriate energy level the selected pulses are cavity dumped to the compressor again using polarization discrimination tech niques Amplification occurs as a seed pulse passes multiple times through the Ti sapphire rod which has been excited by the pump beam of th
111. ys are activated and the EVO LUTION EMISSION indicator turns on The diode laser arrays begin a con trolled ramp up After a delay of 5 to 10 seconds during which a tone sounds the Evolution 15 begins lasing STOP button stops operation of the Evolution 15 pump laser EVOLUTION EMISSION indicator illuminates when current is supplied to the diode lasers that pump the Evolution 15 INTERLOCK indicator turns on when the remote interlock connected to the back of the Evolution 15 power supply has been activated e g when the laboratory door opens The Evolution 15 will shut down turning off the amplified output from the Hurricane i when this indicator comes on This interlock provides 5 Vdc at 250 mA CURRENT SET A control sets the output current in Amps of the diode lasers that pump the Evolution 15 up to the maximum set point The new value can be entered directly or adjusted in 0 1 A increments CURRENT MONITOR A indicator displays the current in Amps of the diode pump laser arrays in the Evolution 15 The current for the Evolution 15 diode laser arrays was set at the factory to achieve optimum performance of the Hurricane i system This con trol is provided in the field for troubleshooting or service only do not change this value unless instructed to do so Hurricane i Integrated Ti Sapphire Amplifier System Regen Panel Note START button starts operation of the regenerative amplifier If all
112. ysics The equipment is used in accordance with the instructions provided in this manual System Components e Hurricane i laser head Mai Tai power supply e Evolution 15 power supply e SDG II controller e Notebook computer with control software pre installed e Achiller with tubing and fittings and its own user s manual e Anaccessory kit see below xvii Hurricane i Integrated Ti Sapphire Amplifier System Accessory Kit xviii Included with the laser system is this manual a test summary a packing slip listing all the components shipped with this order and an accessory kit containing the following items Hardware for mounting the Hurricane i laser head to a horizontal base plate RS 232 serial control cable Interface control software on one CD ROM backup Fuses for the power supplies Model J40 10 A fuses 2 Mai Tai e D sub jumper plugs for the REMOTE and ANALOG ports on the Mai Tai power supply not used on this system e Specification summary form Chapter 1 Introduction The Hurricane i system amplifies the output of a mode locked Ti sapphire laser to produce high power ultrafast pulses The components needed to produce these femtosecond milli Joule pulses at kilo Hertz repetition rates are provided in a single compact assembly Inside this assembly are the Mai Tai seed laser the pulse stretcher regenerative amplifier and pulse compressor as well as the Evolution 15 pump laser which

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