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Millennia V - UCSD Department of Physics

1. Precautions For The Safe Operation Of Class IV High Power Lasers My Wear protective eyewear at all times selection depends on the wave Eyewear P length and intensity of the radiation the conditions of use and the Required visual function required Protective eyewear 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 e Maintain a high ambient light level in the laser operation area so the eye s pupil remains constricted reducing the possibility of damage e To avoid unnecessary radiation exposure keep the protective cover on the laser head at all times e Avoid looking at the output beam even diffuse reflections are hazardous e Avoid blocking the output beam or its reflections with any part of the body e Establish a controlled access area for laser operation Limit access to those trained in the principles of laser safety e Post prominent warning signs near the laser operating area Figure 2 1 e Set up experiments so the laser beam is either above or below eye level e Provide enclosures for beam paths whenever possible e Set up shields to prevent any unnecessary specular reflections e Set up a beam dump to capture the laser beam and prevent accidental exposure Figure 2 2 2 1 Millennia V Diode Pumped CW Visible Laser n Caution ll 2 2 VIS
2. Dirty optics Clean but do not remove the intracavity mirrors Do not attempt to clean the SHG crystal Incorrect pick off calibration Call your Spectra Physics service representative power readout 8 2 Service and Repair Symptom The Millennia V shuts itself off in current mode Possible Causes Corrective Action There should be no reason for Call your Spectra Physics service representative the unit to shut down in cur rent mode other than for power failure or an interlock interruption This will show up on the controller as an error message Symptom The Millennia V will not lase Possible Causes Corrective Action The shutter is not open Move the shutter lever to the open position O A beam tube has fallen into Carefully remove the head cover and reinstall the beam tube the beam path The Millennia V and power The Millennia V turn on will take approx 20 min to complete Allow enough supply have not completed time for the turn on sequence the turn on sequence An interlock is open Ensure that the head cover is properly installed and latched Ensure that the LASER ENABLE key on the power supply is in the ON position Note an open interlock should show up on the controller as an error Symptom Long term stability beam pointing is poor Possible Causes Corrective Action The laser head is not properly Be sure to use the clamps that were supplied with your Millennia V These loc
3. Emission Shutter Indicator Interlock Rigid Light Pickoff Dichroic Output Plano Convex Oven LBO Switch L Resonator Coupler M5 Lens Crystal FCbar Fiber Delivery Bundle Z Head Telescope Intracavity Enclosed Cavity Fold Cavity End Aperture Intracavity Mirror M3 Mirror Mg Beam Path Figure 4 1 The Millennia V Laser Head External Controls Shutter blocks the output beam when the lever is moved to the blocking position The lever is located near the emission indicator on top of the output bezel It is accessible when the cover is on Cover clamping screws 2 hold the cover securely in place One screw 1s located on top of the cover at each end of the laser Use the Allen drivers provided to fasten and unfasten the 1 4 turn screws Millennia V Diode Pumped CW Visible Laser Internal Controls Warning W Indicators Connections 4 2 Foot height adjustments 4 provide a means to level the laser and to adjust its height to match that of the target device The legs are large screws with swivel feet that can be screwed up and down from inside the laser head using an Allen driver Once the height adjustment has been made a jam nut on each leg is tightened up against the chassis to lock them in place NEVER adjust any internal controls other than those listed here Doing so will reguire a major realignment that can only be performed at the factory Such an alignment is not covered by your warranty and
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5. which can take up to 30 minutes A time bar is displayed 0 to 100 to indicate progress System Warming Up 5 When the system has warmed up the following screen is displayed Setup Hold POWER Info key to turn on Set 0 20W Press and hold in the LASER POWER button until the laser starts When the button is pressed the LASER EMISSION light flashes for a few sec onds Then when laser emission occurs it stops flashing and remains on and the emission indicator on the laser head turns on to indicate radiation 1s present At this point the Main menu is displayed and for safety output power ramps up slowly to 0 20 W 0 20 W is displayed if the laser was set to power mode when 1t was last used or an equivalent current value 1s displayed if the laser was set to current mode Power mode is shown in the Main menu below Setup Info P1 P2 Set 0 20W 6 Use the Setup menu to change the laser mode if desired 7 From the Main menu set laser output power using the up down but tons Actual output power will follow the setpoint value This completes the cold start turn on sequence The system is now ready for use Turning On the Laser Warm Start This procedure assumes the unit was left in Standby mode after it was last used 1 e the laser was turned off but the power supply was left on When this is the case the following Standby prompt is displayed STANDBY Press POWER key to
6. Effec tively there is an averaging of the nonlinear coupling terms and the result ant frequency doubled output exhibits extremely low amplitude noise about an order of magnitude lower than that of an ion laser Millennia V Diode Pumped CW Visible Laser The Millennia V System The Millennia V system comprises four basic components e Millennia V laser head e Model 140 power supply e Chiller e Control Module The following sections will be confined to descriptions of the laser head and power supply The control module is fully described in Chapter 6 Operation and the chiller is fully described in the User s Manual shipped with that unit Figure 3 8 The Millennia V System chiller not shown Overview 3 10 In the Millennia V laser head the output from two high power fiber cou pled laser diode bars FCbar is used to end pump the laser gain medium a neodymium yttrium vanadate Nd YVO crystal see Figure 3 10 The FCbar design allows the diode bars to be placed in the power supply which removes their heat load from the laser head and facilitates their field replacement because realignment of the Millennia V cavity 18 not required Laser Description Emission Shutter Interlock Rigid Light Pickoff Dichroic Output Plano Convex Oven LBO Indicator Switch L Resonator Coupler Ms Lens Crystal FCbar Fiber Z Head Telescope Intracavity Enclosed Cavity Fold Cavity End Delivery Bundle Aperture Intracavi
7. are used to control and monitor the Millennia V Sample menu displays are shown in Figure 6 2 kkk SETUP kkk Warming Up Mode Power Stdby Never Setup Menu Mode Select STANDBY Press POWER key to warm up Standby Menu kkk IN FO kkk D1 19 5 Amps S enabled D2 18 9 Amps Main Menu RS 232 Enabled Display Information Menu Figure 6 2 The Millennia V Menus The upper left hand frame shows the warm up menu that is displayed soon after the system is powered up from a cold start the power supply was turned off It allows you to monitor the warm up process which takes Operation The Main Menu The Setup Menu about 30 minutes If you are controlling the system remotely using the serial interface a guery command allows you this same monitoring capa bility refer to the Queries section later in this chapter The Standby menu is displayed anytime the power supply is left on but there has been no laser emission for a time greater than the Stdby delay time setting The following sections describe the four menus When the system is ready for operation following the warm up seguence the Main menu is displayed From here you can set the output power and monitor system performance The large numbers indicate actual output power the smaller numbers below it indicate either the desired output power the power setpoint when the system is set for power mode the desired laser diode drive current
8. 2 4 reserved 3 8 reserved 4 16 reserved 5 32 SYS ERR SE Any system error An open interlock or an internal diagnostic 6 64 LASER ON LO _ Indicates that laser emission is possible 7 128 ANY ERR AE Any of the error bits are set 6 14 Operation Table 6 3 Error Return List Binary Decimal Errors Returned DigitS Value 0100 0000 64 LO 1000 0001 129 CE AE 1000 0010 130 EE AE 1000 0011 131 CE EE AE 1010 0000 160 SE AE 1010 0001 161 CE SE AE 1010 0010 162 EE SE AE 1010 0011 163 CE SE EE AE 1100 0001 193 CE LO AE 1100 0010 194 EE LO AE 1100 0011 195 CE EE LO AE 1110 0000 224 SE LO AE 1110 0001 225 CE SE LO AE 1110 0010 226 EE SE LO AE 1110 0011 227 CE EE SE LO AE 2WARMUP Get Warm up Status WARMUP lt cR gt Reads the status of the system warm up time as a percent of the predicted total time see the table below The system responds with a value simi lar to 050 lt LF gt When the response is 100 lt LF gt the laser can be turned on Note an error condition such as an open interlock may not affect the WARMUP command To check for other errors reguest the status byte with the STB query command System Status 2WARMUP Initial AC power on warm up Between 1 and 99 System is ready to turn on the laser 100 diodes System is in Standby mode 0 System is warming up after leaving between 1 and 99 Standby
9. 4 656 635 4 665 529 Informationen siehe Bedienungsanieltung 929 4 723 257 Laser Klasse 4 nach IEC 825 1 1993 E 003 4 758 459 RAYONNEMENT LASER VISIBLE ET OU INVISIBLE 837 771 4 872 177 Exposition dangereuse de l oeil ou 839 4 908 832 de la peau au rayonnement direct ou diffus i 068 5 410 559 Laser Nd YVO Nd YAG ou Nd YLF Emission S S KOTA j laser ultraviolette visible ou infrarouge gt 683 5 436 990 Consulter le manuel d Installation 749 Apparell a laser de classo 4 IEC 825 1 1993 DANGER INVISIBLE LASER RADIATION WHEN OPEN AND INTERLOCK DEFEATED AVOID EYE OR SKIN EXPOSURE TO DIRECT OR SCATTERED RADIATION VORSICHT UNSICHTBARE LASERSTRAHLUNG WENN ABDECKUNG GEOFFNET UND SICHERHEITSVERRIEGELUNG UBERBRUCKT BESTRAHLUNG VON AUGE ODER HAUT DURECH DIREKTE ODER STREUSTRAHLUNG VERMEIDEN LASER DANTER RAYONNEMENT LASER INVISIBLE DANGEREUX EN CAS D OUVERTURE ET LORSOUE LA SECURITE EST NEUTRALISEE EXPOSITION DANGEREUSE DE L OEIL OU DE LA PEAU AU RAYONNEMENT 0129 3285 CE Warning Label CE Warning Label 15 Patent Label Interlock Defeated 14 Laser Head 16 Figure 2 6 CE CDRH Warning Labels Fuse Label Power Supply 9 S Spectra Physics Spectra Physics Lasers Inc 1330 Terra Bella Avenue Mountain View CA 94043 MANUFACTURED IN USA MODEL Z 106C 08 S N THIS LASER PRODUCT COMPLIES WITH 21 CFR 1040 AS APPLICABLE 0129 2889 1 Z Head Model Serial Identification
10. A 60 Hz 220 Vac 10 at 6 A 50 Hz Voltage Fuse Type 3AG Fj F F 200 240 Vac 10A 10A 3A 100 127 Vac 15A 15A 3A Laser Head Size 91 5 L x 15 2 W x 17 4 H cm 36 0 L x 6 0 W x 6 8 H in Weight 13 9 kg 30 5 Ib Umbilical Length Controller Cable Length Power Supply Size Weight Power Cable Length Chiller Size Weight 3 35 m 11 ft 2 44 m 8 ft 64 L x 41 W x 33 H em 25Lx16Wx13Hin 50 1kg 110 Ib 2 44 m 8 ft 55 9 L x 31 8 W x 56 5 H cm 22 0 L x 12 5 W x 22 3 H in 59 9 kg 132 Ib With casters add 6 9 cm or 2 7 in 3 15 Millennia V Diode Pumped CW Visible Laser Outline Drawings Beam Exit 6 98 Model T40 Control Panel Fl Controller Side View a 26 13 35 6 73 33 91 eh All dimensions in 116785 cm 25 25 64 14 ES E E E E E E E E E ES E E E ES ES E E E E OO E E E E leen E N O wo Model T40 Side View Figure 3 12 Outline Drawings 3 16 Chapter 4 Introduction Controls Indicators and Connections This section defines the user controls indicators and connections of the Millennia V laser system It is divided into three sections the Millennia V laser head the Millennia V control module and the Model T40 power sup ply Information on the chiller can be found in the user s manual that accompanies It Figure 4 1 shows the location of the various components in the Millennia V laser head Laser Head Controls
11. Label 13 THIS PRODUCT IS MANUFACTURED UNDER ONE OR MOR OF THE FOLLOWING PATENTS U S PATENT NUMBERS 4 653 056 4 872 177 5 127 068 4 656 635 4 913 533 4 942 582 4 665 529 4 785 459 4 739 507 4 701 929 4 837 771 5 410 559 4 723 257 4 908 832 5 412 683 4 756 003 4 894 839 5 436 990 4 761 786 5 080 706 5 446 749 Patent Label Power Supply 17 Millennia V Diode Pumped CW Visible Laser CE Declaration of Conformity We Spectra Physics Lasers Inc Industrial and Scientific Lasers 1330 Terra Bella Avenue P O Box 7013 Mountain View CA 94039 7013 United States of America declare under sole responsibility that the Millennia V Diode Pumped Solid State Laser System with Model T40 8SS power supply control module and Neslab CFT 25 Manufactured after December 31 1996 meets the intent of Directive 89 336 EEC for Electromagnetic Compati bility Compliance was demonstrated Class A to the following specifications as listed in the official Journal of the European Communities EN 50081 2 1993 Emissions EN55011 Class A Radiated EN55011 Class A Conducted EN 50082 1 1992 Immunity IEC 801 2 Electrostatic Discharge IEC 801 3 RF Radiated IEC 801 4 Fast Transients I the undersigned hereby declare that the eguipment specified above con forms to the above Directives and Standards pp Steve Sheng Vice President and General Manager Spectra Physics Lasers Inc Industrial and Scientific Lasers December
12. Modes for a Single Line The output of the laser is discontinuous within this line profile A standing wave propagates within the optical cavity and any frequency that satisfies the resonance condition MC a ME 3 Var 3 will oscillate where v is the frequency c is the speed of light L is the opti cal cavity length and m is an integer Thus the output of a given line is a set of discrete frequencies called longitudinal modes that are spaced such that An Se 4 Laser Description Nd as a Laser Medium In commercial laser designs the source of excitation energy for the gain medium is usually optical or electrical Arc lamps are often employed to pump solid state lasers and the output of one laser can be used to pump another e g a Ti sapphire laser can be pumped by an argon ion laser or a diode laser can be used to pump a solid state laser An electric discharge is generally used to excite gaseous media like argon or krypton The Millen nia V uses the output from a diode laser to pump Nd gt ions doped in a yttrium vanadate crystalline matrix Nd YVO The properties of neodymium doped matrices such as yttrium aluminum garnet Nd YAG and yttrium lithium fluoride Nd YLF are the most widely studied and best understood of all solid state laser media The four level Nd jon scheme is shown in Figure 3 4 The active medium is triply ionized neodymium which has principle absorption bands in the red and near inf
13. complexity to the laser since it requires an actively stabilized ring cavity and it may also have power limitations The Millennia V overcomes this chaotic noise problem with the simple patented QMAD quiet multiaxial mode doubling solution which makes use of many axial modes see Fig ure 3 7 T Baer J Opt Soc Am B3 1175 1986 Laser Description A Few Axial Modes N o Cc N a amp a a O E I 0 Freguency Time Single Axial Mode g G b 3 a I 0 Freguency Time Many Axial Modes 0 A T g of MN a ll LTY Frequency Time Figure 3 7 The quiet multiaxial mode doubling QMAD solution to the green problem a The green problem Intracavity frequency doubling in a laser with a few axial modes produces large amplitude fluctuations in the second harmonic output resulting from nonlinear coupling of the modes through sum frequency mixing b The single frequency solution forces oscillation on a single axial mode to eliminate mode coupling c The QMAD solution produces oscillation on many axial modes effectively averaging the nonlinear coupling terms to pro vide highly stable second harmonic output In the Millennia V the laser cavity is stretched to about 1 meter to allow oscillation of over 100 longitudinal modes This facilitates quiet intracavity doubling by reducing the relative power in each axial mode so that no one mode reaches sufficient peak power to induce high nonlinear loss
14. e Spectroscopic grade methanol methyl alcohol or propanol 2 pro panol or isopropyl alcohol Acetone may be used on intracavity optics only do not use it on the fiber bundles e Clean dropper or droplet dispensing unit for the alcohol e Inspection microscope 50 x to 100 x typical Cleaning Laser Optics and Optical Fibers All parts that normally come in contact with laboratory or industrial envi ronments retain surface contamination that can be transferred to optical components during handling cleaning and assembly Indeed skin oils can be very damaging to optical surfaces and coatings and can lead to serious degradation problems under intense laser illumination It is therefore essen tial that only clean items come into contact with optical components and the mechanical parts immediately surrounding them 7 1 Millennia V Diode Pumped CW Visible Laser Warning W Warning W n Caution Bl 7 2 When cleaning optics be very careful not to scratch the optic surface Laser optics are made by vacuum deposited microthin layers of materials of varying indices of refraction on glass substrates If the surface is scratched to a depth as shallow as 0 01mm the operating efficiency of the optical coating will be reduced significantly Losses due to unclean optics or fiber ends which might be negligible in ordinary optical systems can disable a laser and severely reduce the effec tiveness of a frequency doubler Dust on intra
15. lens tissue designated for cleaning eye glasses Such tissue contains silicones These molecules bind themselves to the optic coat ings and can cause permanent damage Also do not use cotton swabs e g Q Tips Solvents dissolve the glue used to fasten the cotton to the stick resulting in contaminated coatings Only use photographic lens tissue to clean optical components Tools and mechanical items used with optical systems should be thor oughly degreased and cleaned preferably in an ultrasonic bath and rinsed in clean solvents acetone or alcohol and or deionized water prior to use If used repeatedly over time these items should be re cleaned at regular inter vals If you have any questions regarding these procedures please contact your Spectra Physics service representative General Procedure for Cleaning Optics Warning W All optics are to be cleaned in place NEVER remove any of the optics in the Millennia V laser They are enclosed to minimize contamination and are designed to be cleaned in place 1f required Removing them will require a major realignment that can only be performed at the factory Such an alignment is not covered by your warranty 7 3 Millennia V Diode Pumped CW Visible Laser Caution It 1s recommended that the customer never clean the SHG doubling crys N ll tal It is very easy to damage the crystal and cleaning is rarely required If you must clean it first make sure the crystal is at roo
16. mode is selected or the percentage of maximum current when current mode 1s selected or RS 232 Enabled 1f the system 1s being operated remotely via the RS 232 serial link LASER EMISSION indicator flashes prior to laser emission then stays on when laser output is present There are no connectors on the control module The 3 m control cable is permanently attached Do not try to remove 1t The cable plugs into the 15 pin controller connector on the rear panel of the laser head Controls Indicators and Connections Model T40 Power Supply All controls indicators and connections on the power supply are made on the front panel Figure 4 4 shows the front panel LCD Display AC Power Laser Emission Interlock Indicator Indicator On Off Key Interlock Jumper Laser Head Laser Head Laser Diode 1 Laser Diode 2 Connector Connector Connector Connector Cable Cable EEE NE MERE ETE EEE EE EEE EEE EE EEE LER EEE EN EEE EE HE EE MENE EK e Je ETE EE EEE Te EEE EEE ee ETE EPP EPER EEE HSH a ME REES 20 Power Cord Power On Off Voltage Select Frequency Fuses 3 Umbilical Connector Connector Switch Jumpers Switch Figure 4 4 The Model T40 Power Supply Control Panel Controls Key switch provides security to prevent unauthorized use of the laser When power is applied and the key is inserted and turned to the ON posi tion the LASER EMISSION indicator lights and emission occurs after about a 6 second de
17. monitoring Because the Millennia V is a closed loop system 1t requires no facility water connections The Millennia V controller provides easy control from virtually any point in the laboratory An 8 foot cable connects the controller to the laser head A simple menu driven control program that uses soft keys and clear large characters on a back lit display provides an easy method of control ling and monitoring the system The intuitive layered menu structure pro vides operational options along with diagnostic information for fast efficient control of the unit For users that prefer to operate the laser remotely either directly or via a computer program a standard serial link is provided on the laser head for connection to a computer or terminal The Millennia V system is manufactured under the following patents 4 653 056 4 761 785 4 942 582 4 656 635 4 785 459 5 080 706 4 665 529 4 837 771 5 127 068 4 701 929 4 872 177 5 410 559 4 123 257 4 894 839 5 412 683 4 739 507 4 908 832 5 436 990 4 756 003 4 913 533 5 446 749 1 3 Millennia V Diode Pumped CW Visible Laser 1 4 Chapter 2 Laser Safety Y W Danger The Spectra Physics Millennia V laser is a Class IV High Power Laser Radiation 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
18. of it then roll the laser to the table The laser head is much lighter than an ion laser of similar size approxi mately 14 kg and 1t can be picked up by one person 5 1 Millennia V Diode Pumped CW Visible Laser 3 Set the laser head on a suitable optical table and alien it to the target system 4 For now roll the power supply under the table or out of the way The umbilical and power cable are each about 3 m long 5 Remove the laser head cover Two screws hold the cover on Use one of the large handled Allen drivers from the accessory kit to turn the screws 14 turn counterclock wise then lift the cover off 6 Adjust the height of the laser head a Loosen the large locking nut on each leg The nuts are threaded onto each leg and jam against the bottom of the base plate to lock the foot in place and to add stiffness to the foot b From inside the laser head use a 9 32 in Allen driver to adjust each leg by screwing 1t up and down c When the height is correct tighten the locking nuts up against the base plate again 7 Secure the laser head to the table with the four foot clamps provided 8 Replace the cover on the laser This completes the laser head installation procedure Installing the Control Module Controller installation consists of setting the unit in a convenient place on the table and plugging the control cord into the 15 pin controller connector on the laser head rear panel Figure 5 1 Horiz
19. power A typical response might be 0 20W lt LF gt C lt CR gt Actual Current Setting Query C lt CR gt Returns a value egual to the actual operating per centage of maximum diode current A typical response might be 75 1 lt LF gt This completes the operation section Chapter 7 Maintenance Preventive Maintenance The Millennia V has been designed for hands off operation requiring minimal maintenance Its top cover protects the internal components from outside contamination and prevents unwanted stray optical radiation from escaping the system The Millennia V should always be operated with the top cover in place Dust tubes are used to enclose the entire cavity beam to minimize the amount of maintenance reguired These too should always be left in place Although removal of the fiber optic bundles is not recommended or needed always inspect clean and re inspect the fiber ends whenever they are removed from the Z head It is recommended to annually check the safety features of the Millennia V to ensure safety is maintained see Chapter 2 Laser Safety for details Equipment Required e Dry nitrogen canned air or rubber squeeze bulb e Photographic lens tissue e Clean forceps or hemostats optional but very helpful e Powder free finger cots or gloves for handling optical components e Fiberholding fixture for cleaning and inspection of fiber bundle optional but very helpful
20. small as possible to min imize the solid state laser threshold Figure 3 6 shows a schematic of a mode matching design of this type Laser Diode Mode Volume TEMpoo Mode Volume Gain Region d Lasing Medium Figure 3 6 Mode Matching For higher output power levels a larger laser diode having a larger emis sion region is necessary The diameter of the TEM mode volume must also be expanded to effectively mode match the volume of the extended diode emission region However increasing the TEM mode volume raises the solid state laser threshold This is undesirable when attempting to cre ate an efficient laser diode design At Spectra Physics we use laser diode bars made from a single monolithic piece of semiconductor material which typically contains ten to twenty laser diodes The bars are ideal as high power pump sources These devices have the same high efficiency as the discrete diode devices yet they allow for the manufacture of a much simpler and more reliable high power pump laser design than is possible in a design incorporating an equal number of discrete devices for the same output power level However the active emission area for these new devices 1s increased from the 200 um range found in low power diodes to 1 cm a ribbon of light The use of these bars has therefore been limited due to the difficulty of mode matching their outputs A number of attempts were recently made by some manufacturers to cou ple the outpu
21. the transition probability depends on the flux of the incident wave and a characteristic of the transition called its cross section The absorption coefficient depends only on the differ ence between the populations involved N and N and the flux of the inci dent wave Laser Description When a material is at thermal eguilibrium there exists a Boltzmann distri bution of its atoms over the array of available energy levels with most atoms in the ground state Since the rate of absorption of all freguencies exceeds that of emission the absorption coefficient at any freguency is pos itive If enough light of freguency vis supplied the populations can be shifted until N N Under these conditions the rates of absorption and stimulated emission are equal and the absorption coefficient at frequency v is zero If the transition scheme is limited to two energy levels it is impossible to drive the populations involved beyond equality that 1s N can never exceed N because every upward transition is matched by one in the opposite direc tion However if three or more energy levels are employed and if their relation ship satisfies certain requirements described below additional excitation can create a population inversion where N gt N A model four level laser transition scheme is depicted in Figure 3 2 A photon of frequency v excites or pumps an atom from E to E If the E to E transition probability is great
22. turn on 8 Power Supply in Standby mode 61 EEPROM data read error 62 AC Fault gt 50ms 63 System Boot Marker 64 Communications error 65 Laser Power Outside Ready Range 66 Power adjust timeout 67 Passbank over temp 68 Passbanks current limited 69 Diode Module ilock test bad voltage 70 Diode Module ilock test bad logic 71 Diode Module Safety Check 2 bad voltage 72 Diode Module Safety Check 2 bad logic 73 Diode Module Safety Check 1 bad voltage 74 Diode Module Safety Check 1 bad logic 81 EEPROM data not available O startup A 1 Millennia V Diode Pumped CW Visible Laser A 2 Code Message 82 EEPROM fault on write condition 83 Bad config for uP 84 Compressor failed startup test 85 Heater failed startup test 86 Shorted therm 2 in power supply 87 Open thermistr 2 in power supply 88 Shorted therm 1 in power supply 89 Open thermistr 1 in power supply 90 Multiple errors 91 Diode over temperature 92 Diode under temperature 93 Current limit passbank 2 active 94 Current limit passbank 1 active 95 Power supply interlock active 96 Safety relay for D2 closed s b open 97 Safety relay for D2 open s b closed 98 Safety relay for D1 closed s b open 99 Safety relay for D1 open s b closed 127 Everything s fine 130 Z head thermistor shorted 131 Z head temperature high 132 Z head thermistor open 133 SHG duty cycle error 134 SHG thermistor shorted 135 SHG thermistor or heater open check cable 136 Head cover i
23. warm up 6 7 Millennia V Diode Pumped CW Visible Laser 6 8 Note a 1 Press the LASER POWER button to begin the short warm up cycle The following prompt is displayed for about 2 minutes while the diode temperature stabilizes STABIZING Diode Tempertature 2 When the system has warmed up the following screen is displayed Setup Hold POWER Info key to turn on Set 0 20W Press and hold in the LASER POWER button until the laser starts When the button is pressed the LASER EMISSION light flashes for a few sec onds Then when laser emission occurs it stops flashing and remains on and the emission indicator on the laser head turns on to indicate radiation is present At this point the Main menu is displayed and for safety output power ramps up slowly to 0 20 W 0 20 W is displayed if the laser was set to power mode when it was last used or an equivalent current value is displayed if the laser was set to current mode Power mode is shown in the Main menu below 0 20 Set 0 20W 3 Use the Setup menu to change the laser mode if desired From the Main menu set laser output power using the up down but tons Actual output power will follow the setpoint value This completes the warm start turn on sequence The system is now ready for use When Standby mode is activated the system automatically reverts to a power down mode after the preset delay time and the Standby menu is displayed
24. warranty does not apply to any instrument or component not manufac tured by Spectra Physics When products manufactured by others are included in Spectra Physics equipment the original manufacturer s war ranty is extended to Spectra Physics customers When products manufac tured by others are used in conjunction with Spectra Physics equipment this warranty 1s extended only to the equipment manufactured by Spectra Physics This warranty also does not apply to equipment or components that upon inspection by Spectra Physics discloses to be defective or unworkable due to abuse mishandling misuse alteration negligence improper installa tion unauthorized modification damage in transit or other causes beyond the control of Spectra Physics This warranty is in lieu of all other warranties expressed or implied and does not cover incidental or consequential loss The above warranty 1s valid for units purchased and used in the United States only Products shipped outside the United States are subject to a war ranty surcharge Return of the Instrument for Repair 9 2 Warning W 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 shippi
25. you will be charged accordingly Interlock switch shuts the laser off immediately when the cover is removed The switch is located behind the shutter near the output bezel It can be defeated using the yellow plastic T shaped key that is clamped to the vertical resonator plate near the switch To defeat the switch insert the key in the slot and press the key down against the spring then rotate it 90 clockwise to lock it in place To remove it rotate it 90 counterclockwise and lift it out While the key is in the defeat position the cover cannot be installed Vertical high reflector adjust M6 provides vertical adjustment for power optimization It is recessed behind the rear bezel Figure 4 2 but it can be accessed using one of the large handled Allen drivers provided Horizontal high reflector adjust M6 provides horizontal adjustment for power optimization It is recessed behind the rear bezel Figure 4 2 but 1t can be accessed using one of the large handled Allen drivers pro vided There is only one indicator on the laser head Emission indicator light warns of present or imminent laser radiation This white light CDRH indicator is located at the top center of the output bezel A built in delay between the turn on of the lamp and actual emission allows for evasive action in the event the system was started by mistake There are three connections on the Millennia V rear panel Figure 4 2 the permanently att
26. 1s present A Laser Radiation Danger W Condition or action may present a hazard to personal safety Danger Condition or action may present an electrical hazard to personal safety Warning W Condition or action may cause damage to equipment Warning Action may cause electrostatic discharge and cause damage to equip ESD ment n Caution a Condition or action may cause poor performance or error Note Text describes exceptional circumstances or makes a special refer ence Don t Do not touch Touch A Appropriate laser safety eyewear should be worn during this opera Eyewear D ti PPTOP yey p Reguired a n Refer to the manual before operating or using this device The following units abbreviations and prefixes are used in this Spectra Physics manual Standard Units Quantity Unit Abbreviation mass kilogram kg length meter time second S freguency 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 O inductance henry H magnetic flux weber Wb magnetic flux density tesla d luminous intensity candela cd temperature celcius C pressure pascal Pa capacitance farad F angle radian rad Prefixes tera 101 T deci 10 d nano 10 n giga 109 G centi 107 c pico 10 p mega 10 M mill 10 m femto 1075 f kilo 103 k micro 109 p atto 101 a XI Unpacking and Inspection Unpacking Your Las
27. 31 1996 Laser Safety CE Declaration of Conformity We Spectra Physics Lasers Inc Industrial and Scientific Lasers 1330 Terra Bella Avenue P O Box 7013 Mountain View CA 94039 7013 United States of America declare under sole responsibility that the Millennia V Diode Pumped Solid State Laser System coupled with the Model T40 8SS power supply and controller meets the intent of Directive 73 23 EEC the Low Voltage directive Compliance was demonstrated to the following specifications as listed 1n the official Journal of the European Communities EN 61010 1 1993 Safety Requirements for Electrical Equipment for Measurement Control and Laboratory use EN 60825 1 1993 Safety for Laser Products the undersigned hereby declare that the equipment specified above con forms to the above Directives and Standards Alu hog Steve Sheng Vice President and General Manager Spectra Physics Lasers Inc Industrial and Scientific Lasers February 21 1997 Millennia V Diode Pumped CW Visible Laser 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 2000 American National 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 Labo
28. 50 1040S 04551 5180 0451 6850 0451 5020 0450 3050 0451 0420S 0451 2480 0451 2490 0451 2500 0451 2510 0451 2520 0129 41068 0129 4106 ETN 3901 13008 TREM C2 08 20 TREM C2 08 30 0425 6951 G0062 000 PCB assemblies are not retrofitable Chapter 9 Customer Service Warranty Customer Service At Spectra Physics we take great pride in the reliability of our products Considerable emphasis has been placed on controlled manufacturing meth ods and quality control throughout the manufacturing process Neverthe less even the finest precision instruments will need occasional service We feel our instruments have excellent service records compared to competi tive products 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 equipment for the money and second by offering service facilities that get your instrument repaired and back to you as soon as possible Spectra Physics maintains major service centers in the United States Europe and Japan Additionally there are field service offices 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
29. 85 to 90 percent of the diode light is transmitted by the bundle thus up to 13 W of usable output is available from each derated laser diode bar at the output of the fiber bundle The FCbar modules mate with the fiber bundle through precision connec tions that are assembled and aligned at the factory The bundles are then terminated at the Z head with industry standard fiber optic connectors Laser Description Specifications This provides a precise and repeatable attachment of the bundle to the Z head and allows the FCbar modules to be replaced in the field if neces sary without reguiring a major realignment Table 3 1 Laser Specifications Power Wavelength Spatial Mode Beam diameter at 1 e points Beam divergence full angle Polarization Power Stability Beam Pointing Stability Noise 5 W 532 nm TEM lt 2 5 mm lt 0 5 mrad gt 100 1 vertical 1 0 lt 5 urad C lt 0 1 rms Specifications subject to change without notice 2 M lt 1 1 Beam ellipticity lt 10 Measured at the exit port Measured over a 2 hour period after a 30 minute warm up from standby mode gt Measured as far field x and y positions after a 30 minute warm up from standby mode 6 Measured over a 10 Hz to 10 MHz bandwidth at the specified output power Table 3 2 Electrical Mechanical Power Supply 110 Vac 10 at lt 10 A 60 Hz 220 Vac 10 at lt 6 A 50 Hz Chiller 110 Vac 10 at 10
30. ECT OR SCATTERED RADIATION CLASS 4 LASER PRODUCT CLASS 4 LASER PRODUCT GaAlAs CW 2 NM MAXIMUM OUTPUT 40 W MAXIMUM OUTPUT 15W 200 240 VAC 10A 10A SA 100 127 VAC 15A 15A 3A SEE MANUAL 0451 8170 SEE MANUAL CE Danger Label CE Danger Label Fiber Cable 7 Laser Radiation 8 Spectra Physics 1344 TERRA BELLA AVENUE MT VIEW CALIFORNIA 94039 MANUFACTURED Nomser MILLENNIA V MONTH MODEL SJ Spectra Physics S Spectra Physics Spectra Physics Lasers Inc 1330 Terra Bella Avenue Mountain View CA 94043 SERIAL NUMBER THIS LASER PRODUCT COMPLIES MADE IN USA WITH 21 CFR 1040 AS APPLICABLE 404 471 MADE IN U S A MANUFACTURED IN USA MODEL T40 8SS Resonator Model Serial Laser Head Model Serial Power SupplyModel Serial Identification Label 10 Identification Label 11 Identification Label 12 VISIBLE AND OR INVISIBLE LASER RADIATION Avoid eye or skin exposure to direct or scattered radiation Nd YVO Nd YAG or Nd YLF Laser Various ultraviolet visible or infrared wavelengths Spectra Physics Lasers may be emitted Consult instruction manual POST OFFICE BOX 7013 Class 4 laser product per IEC 825 1 1993 MT VIEW CA 94039 7013 Noa Bestrahlung von Auge oder Haut durch THIS PRODUCT IS direkte oder Streustrahlung vermeiden PROTECTED BY U S A 7 Nd YVO Nd YAG oder Na YLE Laser PATENT NOS 4 653 056 erschieden Ultraviolett Infrarot oder sichtbara Laserstrahlungen K nnen austreten N here
31. IBLE AND OR INVISIBLE LASER RADIATION AVOID EYE OR SKIN EXPOSURE TO DIRECT OR SCATTERED RADIATION CLASS 4 LASER PRODUCT GaAlAs CW MAXIMUM OUTPUT 40 W AN SEE MANUAL 0451 8170 VISIBLE amp INVISIBLE LASER RADIATION VISIBLE AND OR INVISIBLE LASER RADIATION AVOID EYE OR SKIN EXPOSURE TO DIRECT OR SCATTERED RADIATION CLASS 4 LASER PRODUCT 532 NM MAXIMUM OUTPUT 15 W AVOID EYE OR SKIN EXPOSURE TO DIRECT OR SCATTERED RADIATION 20 W MAX CW GaAlAs 40 W MAX CW Nd YVO IR 1064 nm 15 W MAX CW SHG 532 nm CLASS IV LASER PRODUCT Figure 2 1 These CE and CDRH standard safety warning labels would be appropriate for use as entry warning signs EN 60825 1 ANSI 4 3 10 1 SEE MANUAL Figure 2 2 Folded Metal Beam Target Use of controls or adjustments or performance of procedures other than those specified herein may result in hazardous radiation exposure Operating this laser without due regard for these precautions or in a manner that does not comply with recommended procedures may be dangerous At all times during installation 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 21CFR1040 10 d Follow the instructions contained in this manual to ensure proper installa tion and safe operation of your laser Any electro
32. Millennia V Diode Pumped CW Visible Laser User s Manual G Spectra Physics The Solid State Laser Company 1335 Terra Bella Avenue Mountain View CA 94043 Part Number 0000 245A Rev D November 2001 Preface This manual contains information you need in order to safely install align operate maintain and service your Millennia V diode pumped continu ous wave visible laser The system comprises four elements the Millennia V laser head the T40 power supply the chiller and the control module The latter is a table top controller that is provided with the system The Introduction contains a brief description of the Millennia V laser and Its power supply controller and chiller Following that section is an important chapter on safety The Millennia Vis a Class IV laser and as such emits laser radiation which can permanently damage eyes and skin This section contains information about these haz ards 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 contains a short section on laser theory regarding the Nd YVO crystal and second harmonic generation used in the Millennia V It is followed by a more detailed description of the Millennia V laser sys tem The chapter concludes with system specifications The next few chapters describe the Millennia V controls the
33. Millennia V system No formal alignment procedure is required for the Millennia V laser sys tem there are no knobs to adjust or no optics to change at this point If you are ready to turn on the laser refer to Chapter 6 Operation for instruc tions Chapter 6 Operation Please read this entire chapter and Chapter 2 on laser safety before using your laser for the first time Once the Millennia V has been installed and the output optimized using this procedure we strongly suggest you leave the power switch on the power supply located in the lower left corner of the panel in the on position at all times This will drastically reduce warm up time by keeping the SHG dou bling crystal oven on and will help protect the crystal especially in humid environments Using the Control Module The controller is a convenient device for operating the Millennia V laser refer to Figure 6 1 Use the four buttons on the left side of the panel to select one of the four possible options shown on the left side of the screen For example press the top left button to go to the Setup menu or the next button down to go to the Info menu etc As is the case here not all menus use all the buttons The LASER POWER button turns the laser on and off Select Laser Emission LCD Laser Buttons 4 Indicator Monitor On Off Up Down Buttons 2 Figure 6 1 The Millennia V Controller Showing the Default Main Menu The up down buttons in the l
34. P2 SET allow you to preset two power levels that can be selected from the Main menu during operation by simply pressing one of the two lower left buttons on that screen See the Main menu When RS 232 is selected RS 232 is displayed on the Main menu as shown below and control is transferred to the host system The baud rate can be changed to match the speed of the host system This setting along with the software commands for serial control are explained later in this chapter under The RS 232 Serial Port The default RS 232 settings are 9600 baud 8 data bits no parity 1 stop bit GE enabled Pressing the Main button from the Setup menu returns you to the Main menu When Stdby is activated in the Setup menu the Standby menu is auto matically displayed whenever the Model T40 power supply is left on but there has been no emission for more than the delay time set for Stdby see the Setup menu This is the recommended over night off position Refer to Turning on the Laser Warm Start later in this chapter Operation This display is not shown when the system is started cold i e when the power supply has been turned off Nor can it be accessed from any other menu STANDBY Press POWER key to warm up The Information Menu The Info menu provides diagnostic information on the laser diodes and the SHG doubling crystal It also contains a history HST line that displays the three
35. To restart the unit follow the procedure for a warm start turn on Operation Optimizing Laser Output be able to see any change in power while in power mode the system will compensate for any changes you make Also there must be some output power present before you begin If this 1s not the case call your Spectra Physics representative n Caution W Perform the following adjustment while in current mode You will not Use the two large handled Allen drivers provided in the accessory Kit to adjust the horizontal and vertical controls of the M6 HR These controls are accessed through holes in the laser rear panel as shown in Figure 6 3 Horizontal Adjust Vertical Adjust Figure 6 3 Millennia V Rear Panel 1 From the Setup menu set the system in current mode 2 From the Main menu set the laser for the desired output power 3 While monitoring output power on the controller adjust the horizontal control back and forth until output power is as high as possible Similarly adjust the vertical control 5 Repeat these adjustments first turning one control then the other back and forth until maximum power Is reached 6 Return the system to power mode Do not make any other adjustments to the laser head see warning realignment of the head might be reguired Such a realignment is not Warning W DO NOT make any other adjustments to the laser head or a full factory part of your warranty and you will be charged acc
36. about 5 to 10 counts Adjust the HR for maximum output power The chiller is low on water Add water to the chiller Refer to the chiller manual The Millennia V is misaligned Set the Millennia V to current mode 100 current Adjust the HR for maxi mum output power Symptom Bad mode Possible Causes Corrective Action The SHG temperature is not Set the Millennia V to current mode 100 current Adjust the SHG tempera adjusted correctly ture for maximum output power For long term stability back the SHG count down by about 5 to 10 counts Adjust the HR for maximum output power Note This is very common at low power level due to the lack of self heating from the 1064 nm beam Readjust the SHG temperature as needed The beam is clipping the out Call your Spectra Physics service representative put telescope assembly The Millennia V is misaligned Set the Millennia V to current mode 100 current Adjust the HR for maxi mum output power Symptom The Millennia V shuts itself off in power mode Possible Causes Corrective Action The Millennia V is misaligned Set the Millennia V to current mode 100 current Adjust the HR for maxi mum output power The SHG temperature is not Set the Millennia V to current mode 100 current Adjust the SHG tempera adjusted correctly ture for maximum output power For long term stability back the SHG count down by about 5 to 10 counts Adjust the HR for maximum output power
37. ached umbilical cable from the power supply he 9 pin RS 232 serial port and the 15 pin Millennia V controller connector Controls Indicators and Connections Horizontal Adjust Vertical Adjust RS 232 Serial Port Connector 9 pin Controller Connector 15 pin Umbilical Attachment Figure 4 2 The Millennia V Laser Head Rear Panel Umbilical connector provides control signals to and from the power supply cooling water from the chiller and laser output from the diodes This umbilical is permanently attached do not try to remove it To move the laser system disconnect the chiller supply lines at the chiller and drain the lines then set the laser head and the controller on top of the power sup ply and roll the system to its new location Make sure the cooling lines are reconnected and tightly fastened before you restart the laser after moving it RS 232 serial port connector 9 pin D Sub provides attachment for a host system to operate the system remotely Controller connector 15 pin D Sub provides attachment for the Mil lennia V control module Millennia V Control Module Select Laser Emission LCD Laser Buttons 4 Indicator Monitor On Off Up Down Buttons 2 Figure 4 3 The Millennia V Control Module 4 3 Millennia V Diode Pumped CW Visible Laser Controls Indicators Connections There are 7 buttons on the controller that are used to operate the Millennia V laser Figure 4 3 Sel
38. ain medium must be placed in a resonant optical cavity The latter can be defined by two mirrors which provide feed back to the active medium 1 e photons emitted parallel to the cavity axis are reflected back into the cavity to interact with other excited states Stim ulated emission produces two photons of equal energy phase and direction from each interaction The two photons become four four become eight and the numbers continue to increase geometrically until an equilibrium between excitation and emission is reached Both cavity mirrors are coated to reflect the wavelength or wavelengths of interest while transmitting all others One of the mirrors the output cou pler transmits a fraction of the energy stored within the cavity and the escaping radiation becomes the output beam of the laser The laser oscillates within a narrow range of frequencies around the transi tion frequency The width of the frequency distribution the linewidth and its amplitude depend on the gain medium its temperature and the magnitude of the population inversion Linewidth is determined by plotting gain as a function of freguency and measuring the width of the curve where the gain has fallen to one half max imum full width at half maximum or FWHM Figure 3 3 Longitudinal Modes Gain Envelope FWHM Point 5 6 10 GHz Frequency v gt Figure 3 3 Frequency Distribution of Longitudinal
39. cavity mirror surfaces can reduce output power or cause total failure Cleanliness 1s essential How ever as long as the Millennia V intracavity optics are kept enclosed 1 e the dust tubes are never taken off and the fiber optics are not removed from the Z head there is little need for the routine maintenance associated with ion lasers However if cleaning 1s required the maintenance tech nigues described below must be applied with extreme care and with atten tion to detail Remember clean is a relative description nothing is ever perfectly clean and no cleaning operation ever completely removes contaminants Clean ing 1s a process of reducing objectionable materials to acceptable levels Never clean the crystals with solvents especially the SHG doubling crystal Only use puffs of air to remove dust If the crystals become con taminated consult the factory NEVER remove any of the optics in the Millennia V laser They are enclosed to minimize contamination and are designed to be cleaned in place when and if reguired Removing them will reguire a major realign ment that can only be performed at the factory Such an alignment is not covered by your warranty Always wear clean lint free finger cots or gloves when handling optics and intracavity parts Remember not to touch any contaminating surface while wearing gloves you can transfer oils and acids onto the optics e Workin a clean environment and whenever possible
40. ctra Physics Millennia 1 02 O lt LF gt 2STB Get Status Byte This guery reguests a system status byte that indicates which command errors if any have occurred and whether the laser is on or off The integer value returned represents the sum of the value of the bits in the status byte The bit positions are defined by Table 6 2 below Each time a status byte is reguested its register is cleared so that a new status byte can be generated The status register accumulates the most recent commands and tracks their validity Consider the following seguence of commands P 10 lt CR gt Since the reguested power is out of range the EXE ERR bit is set P 5 lt CR gt Valid command sets power to 5 watts M1 lt CR gt Valid command sets unit to power mode ON lt CR gt Valid command turns on the laser diodes STB lt CR gt Reads and clears the status byte The status byte returned would be 194 lt LF gt since the ANY ERR LASER ON and EXE ERR bits are set 194 2 64 128 Table 6 2 describes all the possible errors Table 6 3 lists all the possible combina tions Binary Decimal Name Interpretation Digit Value 0 1 CMD ERR CE Command error Something was wrong with the command format the command was not understood 1 2 EXE ERR EE Execution Error A command was properly formatted but could not be executed For example a power command of P 0 lt CR gt was sent when the minimum allowed power is 0 2 watts
41. d CW Visible Laser The Laser System Laser Head Power Supply 1 2 The Millennia V system comprises four basic components e Millennia V laser head e Model 140 power supply e Chiller e Control Module The Millennia V laser head houses the optical resonator the neodymium yttrium vanadate NdYVO gain medium the diode laser fiber delivery and telescope focusing systems the lithium triborate LBO doubling crystal and the output beam telescope system Externally it resembles a standard small frame ion laser head Indeed its dimensions overall footprint and output beam location make it a drop in replacement for one However because there is no plasma tube magnet or water jacket the Millennia V laser head is shorter and weighs far less than an equivalent ion laser head it can even be handled and moved easily by one person In addition because the laser head is not subjected to the large heat load of a plasma tube nor reguired to support a heavy magnet assembly only a simple resonator design is employed Nevertheless it is sufficiently robust to deliver beam pointing stability as good as that from an actively stabilized ion laser To further improve stability and provide long term hands off operation the entire intracavity beam path is totally enclosed The highly efficient diode pumped Nd YVO laser crystal requires far less cooling water flow than a plasma tube of comparable output power over two orders of magnitu
42. d IEA AA AA EE AAA AAA A 4 5 Jete Wee seere aia AES 4 6 COME NNN coast Sok Sart as EE 4 6 Chapter 5 Installation and Alignment 0000 cee ee 5 1 EASePINStalA HON iia AS Blew ARA AE EA A 5 1 Installing the Laser Head REESEN 5 1 Installing the Control Module 5 2 Installing the Power SUPPI caca rai AAA AA A e ER 5 3 Installing the Ghiller seseris AA A A A A ASA N 5 3 ANA MEN nao ni atada re rd a ts ON so S dalt 5 4 CRhapter6 e ET Le EE 6 1 Using the Control Module 2 ll oss ee ee ee eee eee teen eens 6 1 ThE MENU S SEM viem ea A Es un VTS AUS a VEE aa JADE ASS is Be 6 2 Ke ie Rn E EE 6 3 The Setup Mentiroso padrastro 6 3 The Stanaby Menta caridad seere de ST o at da 6 4 TEMOM UoN MENU senda EE 6 5 System STAMEUP S TUI OW vita cl RA a dle v a 6 6 Turing On the Laser Cold Stalin A ac a 6 6 Turning On the Laser Warm Start aavavva vnr vnr eee eee eee 6 7 OptmIizIAG Laser OMPUL 1 2 5520 dl rd he eee ese eee 6 9 vi Table of Contents TUrAING Ot ts LAS asa ita EE 6 10 Setting the SHG Crystal Temperature 2 oloon sk K K n 6 10 TRES RS 232 Sea PO donas Res EEN geg E a la Heiss kana Re wees 6 11 Pro MI A A II de dan ed es 6 11 Communications Parameters escobar a 6 11 Command Query Response Format soon vnr eee eee r nn 6 12 Emma see 6 12 a TS A Ee EE e 6 13 Chapter 7 Maintenance sevi dao ewe iw eee Sete eww awe ei SG 7 1 Preventivo Malhtohan er 7 1 Equipment Required ee n 7 1 Cleaning Lase
43. de less This virtually eliminates low frequency opti cal noise which is a major problem for water cooled ion lasers A small chiller is provided to supply this cooling The noncritically phase matched LBO doubling crystal is housed in an oven that maintains it at an optimum temperature for stable output The Model 140 power supply houses the two fiber coupled 20 W diode laser bars that pump the Millennia V head Each diode bar is operated at less than 75 of its rated power in order to maintain ideal operating condi tions for the diodes and thus ensure a long lifetime The power supply also contains the control logic and power modules for the system as well as the refrigeration unit that cools the diodes The power supply is air cooled and reguires no water or external cooling connections For electrical power it simply reguires a standard 110 or 220 Vac 10 A power source The power supply is small about 31 x 41 x 64 cm 13 x 16 x 25 in and it weighs about 50 kg 110 Ib Rubber casters are provided for mobility and to permit easy stowage It can also be rack mounted Chiller Control Module Patents Introduction A single umbilical cable connects the supply to the laser head It contains the power and control cables fiber bundles and cooling lines The compact recirculating chiller regulates the temperature of the Nd Y VO crystal in the laser head and the cooling fluid temperature is displayed on the chiller for easy
44. djusting the vertical and horizontal controls of the high reflector e 27 32 in Allen hex driver for adjusting the feet laser height e table clamp kit 4 clamps and hardware e plastic hemostat e lens tissue e tweezers xiii Millennia V Diode Pumped CW Visible Laser e 2 keys for the power supply e Z head output coupler e fiber endcaps e Z head telescope endcaps e jumper plug for RS 232 only operation XIV Chapter 1 Introduction The Millennia V Advantage The Millennia V is an all solid state high power visible cw laser that pro vides greater than 5 W of green 532 nm output from a standard 110 or 220 Vac single phase outlet The laser head has the same footprint and output beam position as conventional small frame ion lasers and offers beam guality beam pointing and amplitude stability that are egual to or better than ion lasers In addition the optical noise is more than an order of mag nitude lower than that of an ion laser All this performance is possible through the integration of our patented high efficiency FCbar diode pumping and QMAD intracavity doubling technologies Because the Millennia V is all solid state it is much more reliable and eas jer to use than an ion laser With its much greater conversion efficiency lt 500 W of waste heat vs about 20 kW for a small frame ion laser its operating cost is much lower Figure 1 1 The Millennia V System 1 1 Millennia V Diode Pumpe
45. e in a single motion Be careful that the hemostat does not touch the optic surface or the coating may be scratched 4 Inspectthe cleaned optic under ample light to verify the optic actually got cleaner 1 e you did not replace one contaminant with another 5 Replace the dust cover s Never leave the covers off longer than it takes to clean the optic This concludes the procedure for cleaning optics 7 4 Maintenance General Procedure for Cleaning Fiber optic Bundles Danger Laser Radiation Prior to cleaning the fibers it is advisable to briefly inspect the fiber end coatings for damage or burn areas Before you do this however turn off the power supply to ensure the diode is disarmed The fibers may be easily cleaned using a fiber holder such as Spectra Physics P N 0129 2872 and a small inspection microscope 50 to 100 power In lieu of the holder it is advisable that the fiber connector be gen tly held in a small clamp or vise that 1s lined with clean lens tissue When ever the exposed fiber ends are handled always wear clean dust free finger cots or gloves Inspection of the fiber end coatings should reveal a uniform bluish smooth and shiny surface with few scratches inclusions or dust particles After initial inspection the fiber ends should be cleaned by one or both of two methods described below as required to achieve the desired results 1 Begin the cleaning using the drop and drag meth
46. ead and power supply already connected Do not disconnect the umbilical cables from either end The following installation procedure is not intended as a guide to the initial installation and set up of your laser Please call your Spectra Physics service representative to arrange an installation appointment which is part of your purchase agreement Allow only personnel guali fied and authorized by Spectra Physics to install and set up your laser Spectra Physics provides training in the use of this laser Please contact your Spectra Physics Lasers representative 1f you desire training You will be charged for repair of any damage incurred if you attempt to install the laser yourself and such action might also void your warranty All the tools and eguipment you need to set up the Millennia V laser are in your accessory Kit Installing the Laser Head Warning W 1 Remove the laser head power supply and control module from the shipping crate and inspect for damage Refer to the Unpacking and Inspection notes at the front of this manual 2 Movethelaser system into place Be careful when moving your system that any bend in the umbilical does not exceed the 10 cm 4 in minimum radius Exceeding this limit can fracture and or break the fiber bundles Also be careful not to snag any of the various cables extending from the power supply To move the laser set the power supply on the ground and the laser head and controller on top
47. ect buttons 4 are located to the left of the LCD screen and are used to select one of the four possible actions that are shown on the left side of the screen For example pressing the top left button in Figure 4 3 brings up the Setup menu When up down arrows are shown on the screen press the associated button to scroll the text LASER POWER button performs 3 functions a begins the laser warm up cycle b turns on the laser and c turns off the laser Note the power supply must also be on and 1ts LASER DIODE interlock keyswitch set to ON in order for the laser to turn on Press the button once to begin the warm up cycle Then when the cycle completes press and hold it in to turn on the laser The LASER EMISSION indicator on the controller panel flashes and the emission indicator on the laser head turns on while the button is held in and emission is imminent a CDRH delay of about 6 seconds The indica tor stops flashing and stays on when emission occurs Up down buttons in the lower right corner of the panel when pressed increase or decrease the value displayed on the screen such as a power set point or allow the operator to select a parameter from a list that 1s to be changed or displayed LCD monitor provides feedback and control of the laser depending on which menu is displayed Large digits always display actual output power Below output power displayed in smaller text 1s the output power setpoint when power
48. ed to the sys tem and the power switch is turned on LASER EMISSION indicator turns on when the LASER DIODE keyswitch is set to the ON position thus indicating there is laser emission or that it is imminent LCD display is a 4 line 20 character display that shows the progress of the power up diagnostics and will display error codes for any power supply failure s These codes are used by Spectra Physics service technicians to diagnose problems in the power supply they are not for use by the user INTERLOCK connector 2 pin provides attachment for a safety switch These contacts must be shorted together before the laser will operate A defeating jumper plug is installed at the factory to permit operation without a safety switch The plug can be replaced with a similar non shorting plug that is wired to auxiliary safety equipment such as a door switch to shut off the laser when actuated opened Such a switch must have a minimum rating of 100 mA at 12 V REMOTE connector 15 pin provides attachment for a jumpered plug that configures the Model T40 power supply for use with the Millennia V laser Do not remove the plug doing so will keep the system from starting or will shut it off if it is already on Do not confuse this connector with the 15 pin connector on the laser head SERIAL COM connector 9 pin provides attachment for control lines from the umbilical Do not disconnect the umbilical connector attached to it Also d
49. er Your Millennia V 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 Carefully inspect your laser system as you unpack it If any damage is evi dent such as dents or scratches on the covers or broken knobs etc imme diately notify the carrier and your Spectra Physics sales representa tive 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 System Components Accessory Kit The following components comprise the Millennia V laser system e Millennia V Laser Head e Model T40 Power Supply e Chiller e Control Module Verify all four components are present The laser head power supply and controller are shipped in one container the chiller is shipped separately Included with the laser system is this manual a packing slip listing all the parts shipped and an accessory kit containing the following items e 1 US or European German power cord 2 m e 21arge handled 3 32 in Allen ball drivers for a
50. er than that of E to E and if the life time of an atom at E 1s short the atom will decay almost immediately to If E 1s metastable 1 e atoms that occupy it have a relatively long lifetime the population will grow rapidly as excited atoms cascade from above The E atom will eventually decay to E emitting a photon of frequency v Finally if E 1s unstable its atoms will rapidly return to the ground state E keeping the population of E small and reducing the rate of absorption of v In this way the population of E is kept large and that of E remains low thus establishing a population inversion between E and E Under these conditions the absorption coefficient at v becomes negative Light 1s amplified as it passes through the material which is now called an active medium The greater the population inversion the greater the gain Ex Es _4 V2 Vi Eo Es Figure 3 2 A Typical Four level Transition Scheme A four level scheme has a distinct advantage over three level systems where E 1s both the origin of the pumping transition and the terminus of the lasing transition Also the first atom that is pumped contributes to the population inversion in the four level arrangement while over half of the atoms must be pumped from E before an inversion is established in the three level system 3 3 Millennia V Diode Pumped CW Visible Laser Resonant Optical Cavity 3 4 To sustain lasing action the g
51. er values for P1 and P2 or to select LOCAL con trol using the Millennia controller or a remote control source via the RS 232 link Access this menu from the Main menu 6 3 Millennia V Diode Pumped CW Visible Laser The Standby Menu KKK SETUP KKK Mode Power Stdby Never Use the two lower left buttons to scroll the menu up and down the selected item is the one between the horizontal arrows Mode Power in the example screen above The value for the selected item 1s changed by using the up down buttons to the right of the screen The selections and or changes are activated upon return to the Main menu Selections include e Mode Power Current RS 232 e Stdby Never 4 hours 2 hours I hour 30 min 15 min e PI Set any value between 0 2 and 5 0 W e P2 Set any value between 0 2 and 5 0 W Power mode is used to maintain constant output power and is the normal setting Current mode is used to maintain constant diode current while measuring laser output power Current mode is primarily used for diode diagnostic purposes Standby Stdby mode when active causes an automatic system power down mode whenever the power supply is left on but there has been no laser emission for a time greater than the Stdby delay time setting This is the preferred off mode when the laser is used on a day to day basis This mode can be defeated however by setting the delay time to Never P1 SET and
52. higher gain and c the crystal can be easily optimized for maximum conversion efficiency by simply chang ing its temperature with no realignment of the laser cavity In frequency doubling the second harmonic power P IS given by Pa a EPEN ss where d 18 the effective nonlinear coefficient P 1s the fundamental input power 1s the effective crystal length 0 is a phase matching factor and A is the cross sectional area of the beam in the crystal Since the second har monic output is dependent upon the square of the fundamental peak power very high conversion efficiencies can be achieved by enhancing the inten sity of the fundamental wave through intracavity frequency doubling or through the use of an external cavity resonant doubler The former is used in the Millennia V Historically free running intracavity doubled diode pumped solid state lasers have typically yielded chaotic output with large amplitude fluctua tions that render the laser output useless for most scientific applications This was first identified at Spectra Physics over ten years ago in a short cavity diode pumped Nd YAG laser with a KTP intracavity doubler it has since become known as the green problem Part of the cause of the insta bility arises from nonlinear coupling of axial modes via sum frequency mixing in the laser cavity The problem can be circumvented by forcing oscillation on a single longitudinal mode However this adds considerable
53. ional perfor mance and maintain constant output power The light pick off is an integral part of the output telescope system The Model T40 Power Supply FCbar The FCbar System 3 14 The pump source for the Millennia V laser head consists of two diode laser bars each module capable of producing 20 W The two modules are then coupled to optical fiber bundles that transport the diodes output to each end of the laser crystal in the Z head This modular concept is called a fiber coupled bar or FCbar FCbar technology enables the high power levels available from the laser diode bars to efficiently end pump the Nd YVO laser crystal This is done by first collimating the output of the bar with a cylindrical microlens of high numerical aperture the microlens is bonded to the diode bar in order to reduce the fast axis divergence of the diode bar The highly asymmetric light is then coupled into a fiber bundle which in turn delivers exceptional brightness to the crystal To stabilize the output wavelength of the diodes the modules are mounted directly on a temperature regulated cold plate Because the coupling technology is so efficient the 20 W diode modules are typically derated 75 to increase their operating lifetime The multimode optical fiber bundle is actually several fibers that are drawn together in a round bundle where the output end is typically 1 to 1 5 mm in diameter with a numerical aperture of about 0 1 Typically
54. is timme m aia a adas Alea 2 10 Eoupmen and HEMING EE 2 11 Chapter 3 Laser Description 00oocococcocn es 3 1 A Brief Review of Laser Theory o ooocooccoco ee N 3 1 EMISSION ANG ADSOPUON OF LONT ciar cri Skee bena enka 3 1 Millennia V Diode Pumped CW Visible Laser eelef lo Rieger Mexica a 3 2 Resonant Optical Cavity curras liada oh es ii a it id 3 4 Nd as a Laser Medium econ tada dre o ao 3 5 Diode pumped Laser Design eee eee eee ene eee eens 3 6 Frequency DOUDIING cs iaa tues te tae EE 3 8 The Millennia NEE A iris ei en od eee one aka EE abd wo 3 10 OV VIEN oscar RR 3 10 The Millennia V Laser Head 3 12 VIE ZN DEE 3 12 The Frequency Doubling Am 3 13 TNE BEANDENEN AM civic ty ar Seed versene eal a onal G 3 14 The Model T40 Power Supply avav navn vann arna n 3 14 FLER 3 14 RRE EEN 3 14 SPec tons uu EE TRE era a one eat 3 15 OMA AA E A ES 3 17 Chapter 4 Controls Indicators and Connections e ences 4 1 Jegen Leide Maia sas a ios 4 1 Laser Head CONOS crias miss Sd da in vos Ta Greta isi te whe we ai Pweg ec ie ti aa 4 1 ExtemaL CONTOS asia AA Guero a aoe a S Kosta el Ea 4 1 Jee e ein dr EE sI ai ghar Bags Beas a 4 2 INAICAOS se ST Pre ares GE 4 2 CONIC COIs EE aras eli ia rs ti ed ae a dae 4 2 Millennia V Control Module st csi E A A N E ds 4 3 COMO ir nd NE Haun o 4 4 Jete Wee 4 4 COTE CHOI oat Ko ais atea cod diia cd ii dra EEN 4 4 Model TAO Ge ele EE 4 5 CONITOIS isis y ae
55. ive 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 2 11 Millennia V Diode Pumped CW Visible Laser 2 12 Chapter 3 Laser Description A Brief Review of Laser Theory Emission and Absorption of Light Laser is an acronym derived from Light Amplification by Stimulated Emis sion of Radiation Thermal radiators such as the sun emit light in all direc tions the individual photons having no definite relationship with one another But because the laser is an oscillating amplifier of light and because its output comprises photons that are identical in phase and direc tion it is unique among light sources Its output beam is singularly direc tional monochromatic and coherent Radiant emission and absorption take place within the atomic or molecular structure of materials The contemporary model of atomic structure describes an electrically neutral system composed of a nucleus with one or more electrons bound to it Each electron occupies a distinct orbital that represents the probability of finding the electron at a given position relative to the nucleus Each orbital has a characteristic shape that is defined by the radial and angular dependence of that probability e g all s orbitals are spherically symmetrical and all p orbitals surround the x y and z axes
56. ked down to the optical clamps were specially designed to eliminate any side loads to the Millennia V table feet which causes undo stress to the resonator The jam nuts on the feet are Once the laser position and height have been adjusted the jam nuts should be not locked adjusted all the up and tightened against the bottom plate The routing mirrors are not If the routing mirrors are used as part of the beam delivery set up ensure that installed correctly they are assembled and locked down correctly 8 3 Millennia V Diode Pumped CW Visible Laser Replacement Parts 8 4 The following is a list of parts that may be purchased to replace broken or misplaced components Also listed are optional components that may be purchased to enhance your system Table 8 1 Replacement Parts List Description Part Number Main pc board assembly through S N 1320 Main pc board assembly S N 1321 through 1432 Main pc board assembly starting at S N 1433 Software upgrade kit up through S N 1320 only Optic retainer 10 ea Doubler oven assembly with crystal Light pick off assembly Table clamp kit Beam tube kit Beam tube snap adapter kit 10 ea High reflector adjust drivers Diode module assembly new Diode module assembly ETN Light bulb white 28 V emission indicator 10 ea Controller Millennia V through S N 1432 Controller Millennia V starting at S N 1433 Polarization rotator Beam splitter 04
57. l being determined by the radial and angular dependence of the probability Likewise when an atom excited to E decays to E it loses energy equal to E E The atom may decay spontaneously emitting a photon with energy hv and frequency E E 2 h Spontaneous decay can also occur without emission of a photon the lost energy taking another form e g transfer of kinetic energy by collision with another atom An atom excited to can also be stimulated to decay to E by interacting with a photon of frequency v emitting energy in the form of a pair of photons that are identical to the incident one in phase fre quency and direction This is known as stimulated emission By contrast spontaneous emission produces photons that have no directional or phase relationship with one another y A laser is designed to take advantage of absorption and both spontaneous and stimulated emission phenomena using them to create conditions favor able to light amplification The following paragraphs describe these condi tions The net absorption at a given frequency is the difference between the rates of emission and absorption at that frequency It can be shown that the rate of excitation from E to E is proportional to both the number of atoms in the lower level W and the transition probability Similarly the rate of stimulated emission is proportional to the population of the upper level N3 and the transition probability Moreover
58. lay Control then transfers to the Millennia V controller or to the host system via the RS 232 link depending on configuration Frequency switch provides a means to set the system for 50 or 60 Hz operation Verify this switch is correctly set prior to turning on the system To set 1t slide 1t to the position that matches the line frequency you are using 4 5 Millennia V Diode Pumped CW Visible Laser Indicators Connections On off switch provides power to the laser system when set to the on I position When first turned on the power supply performs an internal diag nostic check and the doubler oven in the laser head is allowed to warm up From a cold start this takes about 30 minutes It is therefore strongly rec ommended that this switch be left in the on position unless the system is not to be used for an extended period of time For safety however turn off the LASER DIODE key and remove it to prevent unauthorized use of the laser Fuses F1 F2 F3 provide a safety valve for various circuits Replace fuses F1 F2 and F3 according to the table below for the line voltage used To access a fuse use a medium flat blade screwdriver to turn the slotted fuse cap counter clockwise then pull the cap off and remove the fuse Assemble in reverse order Voltage Fuse Type 3AG F F F 200 240 Vac 10 A 10 A 3 A 100 127 Vac 15 A 15 A 3 A AC indicator turns on immediately when line power is appli
59. lk screened voltage notation next to the terminal strip If the voltage is changed fuses F and F must also be changed Refer to the fuse rating requirements for the voltage set ting used in the specifications table in Chapter 3 5 Verify the freguency switch is set to the line freguency in your area 6 Attach the power cord to the power supply then to the power source This completes the installation of the power supply and the Millennia V system Refer to the User s Manual that came with your chiller for detailed infor mation on installing and starting the chiller 1 Place the chiller on the floor close enough to the power supply so the chiller hoses can reach from the chiller connectors on the back of the unit to the umbilical bracket near the power supply Do not place the chiller above the laser If the unit is installed incor rectly and develops a leak dripping water may damage the laser 2 Screw both hoses onto the chiller and tighten The hose connections are not polarized Finger tight is enough do not overtighten 3 Verify there is water in the chiller then turn on the chiller and verify water 1s flowing 4 Inspect for leaks at the hose connections and also inside the laser head where the polyurethane hoses attach to the Z head 5 Set the chiller temperature for 18 C 64 F 5 3 Millennia V Diode Pumped CW Visible Laser Alignment 6 Turn off the chiller This completes the installation of the
60. llennia V Laser Head Rear Panel 0 0 00 c eee eee eens 4 3 Figure 4 3 The Millennia V Control Module 4 3 Figure 4 4 The Model T40 Power Supply Control Panel 4 5 Figure 5 1 The Millennia V Laser Head Rear Panel 0 0 0 cece eee eee ene 5 2 Figure 6 1 The Millennia V Controller Showing the Default Main Menu 6 1 Figure 6 2 The Millennia V Menus 2 00 cee eee een ee eee een 6 2 Figure 6 3 Millennia V Rear Panel ll sossun N 6 9 Figure 6 4 Laser head pc board showing location of baud rate dip switch Sy 6 11 Figure 7 1 Lens Tissue Folded for Cleaning 0 0 00 ccc ee eee eee vnr 7 4 List of Tables Table 3 1 Laser Specifications 0 0 0 0 ee ee eee eee eens 3 15 Table 3 2 Electrical Mechanical coi dara isa bea ewe une oo 3 15 MAIS Ge UWI Op copos Adare daa mi Gee eas p 6 11 Nable6 2 QUEST EMOS rosso cis te othe elo hee eee oe es 6 14 able 6 3 EMOT Returni List rca 5380225 Bhd dd a Ko ea ee A 6 15 Table 8 1 Replacement Parts List n nnana anaana taku Reese oud Reese eine eee it did 8 4 viii 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 Danger Laser radiation
61. m temperature by turning off the power supply and letting the crystal cool down Once it is cool blow air on it using a rubber sgueeze bulb Do not use canned air or dry nitrogen cold air can damage the crystal The crystal protrudes from the ends of the oven housing and it is very fragile It is also very susceptible to damage caused by solvents Damage caused by cleaning is not covered by your warranty Remove the dust cover s for the optic to be inspected and or cleaned 2 Use a squeeze bulb or dry nitrogen to blow away any dust or grit on the surface then test to see if a normal power level returns If power is acceptable do not clean any further If canned air is used hold the can in an upright position to avoid liguid freon from contaminating the optic 3 If solvent cleaning is required use a tissue folded in a hemostat to clean the optic Figure 7 1 Lens Tissue Folded for Cleaning a Fold a piece of lens tissue into a pad about 1 cm on a side and clamp it in a hemostat Figure 7 1 b Ifreguired cut the paper with a solvent cleaned tool to allow access to the optic c Saturate the pad with methanol shake off the excess resaturate and shake again No not use excessive solvent Excess solvent can wick or run down the surface and can attack any adhesive that might be holding the optic to the mount or base and either loosen it or worse contaminate the optical surface with adhesive material d Wipe the surfac
62. mode HDREV Get Head Software Revision 2HDREV lt CR gt Returns a Millennia V laser head software revision number similar to 2 01 lt LF gt 6 15 Millennia V Diode Pumped CW Visible Laser 6 16 PSREV Power supply Software Revision Query PSREV lt CR gt Returns a Model T40 power supply software revi sion number similar to 4420 REV D lt LF gt RMREV Controller Software Revision Query RMREV lt cR gt Returns the controller software revision number A typical response is 1 10 lt LF gt 2EC System Error Code Ouery EC lt CR gt Returns the current error code The code returned is the same as that displayed on the controller if it is attached Refer to the error code listing in appendix A for explanations 2H History Buffer Query 2H lt CR gt Returns a 16 byte 16 code error list from the his tory buffer with the most recent error listed first The history buffer only stores error codes generated by the power supply numbers O 126 Errors from the Millennia V laser head are not recorded and therefore will not be returned C SET Last Current Command Query C SET lt CR gt Returns the value for the last percentage current commanded C not the actual diode current A typical response might be 75 1 lt LF gt PSET Last Power Command Query PSET lt CR gt Returns the value for the last power command P not the actual laser output
63. most recent system error codes for diagnostic purposes The codes and their definitions are listed in Appendix A Note that only the power supply codes 0 through 126 are displayed The Info menu is accessed from the Main menu KKK INFO KKK D1 19 5 Amps D2 18 9 Amps Use the select buttons not the up down buttons to scroll the screen note the down arrow in the picture above Two lines are displayed at a time as follows from top to bottom e The drive current for each laser diode D and D Note that it is normal to require greater than 60 of full current before achieving the threshold condition for green output power e The temperature of each laser diode e The status of the SHG doubling crystal temperature it is STABLE when the proper temperature is reached e The error code history HST line e The revision level of the Millennia V software Have this revision num ber available whenever calling for service Pressing the Main button returns you to the Main menu 6 5 Millennia V Diode Pumped CW Visible Laser System Start up Shut Down There are two turn on sequences one for a cold start when the Model T40 power supply was turned off and one for a warm start when the system 1s in Standby mode when the laser is off but the power supply was left on Each sequence is described below Turning On the Laser Cold Start 6 6 l 4 Verify that all connectors are plugged into the power supply they
64. n guide you through its installation alignment and operation The last part of the man ual covers maintenance and service and includes a replacement parts list and a list of world wide Spectra Physics service centers you can call 1f you need help Whereas the Maintenance section contains information you need to keep your laser clean and operational on a day to day basis Service and Repair is intended to help you guide your Spectra Physics field service engineer to the source of any problems Do not attempt repairs yourself while the unit is still under warranty instead report all problems to Spectra Physics for warranty repair 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 Immunity 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 compliance was demonstrated for EN 61010 1 1993 Safety Requirements for Electri cal Equipment for Measurement Control and Laboratory use and EN 60825 1 1992 Radiation Safety for Laser Products Refer to the CE Dec laration of Conformity statements in Chapter 2 Millennia V Diode Pumped CW Visible Laser Finally 1f you encounter any difficulty with the content or style of this manual please let us know The last page 1s a form t
65. nction of the switches Table 6 1 Switch S Position 1 Position 2 Baud Rate off off 1200 off on 2400 on off 4800 on on 9600 default Baud Rate Dip Switch S4 Figure 6 4 Laser head pc board showing the location of baud rate dip switch S4 Millennia V Diode Pumped CW Visible Laser Command Query Response Format All commands and responses are in ASCII format Commands to the Mil lennia V system are terminated by an ASCII carriage return line feed or both All responses from the Millennia V are terminated by an ASCII line feed character In the examples below a carriage return is indicated by lt CR gt and a line feed by lt LF gt Commands ON Turn On Laser ON lt CR gt If the response to WARMUP is 0 1 to 99 100 The response to this command depends on whether or not the system is warmed up Use the WAR MUP query see Queries to determine the pro gress of the warm up cycle see table below A response of 0 means the system 1s in Standby mode If this 1s the case issue an ON command to begin the temperature stabilization cycle When the response to the WARMUP query reaches 100 the laser can be started Do not issue an ON com mand while the response to WARMUP is 1 to 99 The response to ON is to begin diode temperature stabilization approximately 2 minutes an execution error The EXE ERR bit in the status byte is set the laser diodes
66. ng boxes have been lost or destroyed we recom mend that you order new ones We can return instruments only in Spectra Physics containers Always drain the cooling water from the laser head before shipping Water expands as it freezes and will damage the laser 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 warranty coverage Service Centers Customer Service 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 mall niwamuro O splasers co jp 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 Q splasers com Internet www spectra
67. nic 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 Maintenance Necessary to Keep this Laser Product in Compliance with Center for Devices and Radiological Health CDRH Regulations This laser product complies with Title 21 of the United States Code of Fed eral Regulations Chapter 1 subchapter 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 CDRH Radiation Control Drawing found later in this chapter function properly Also make sure that all warning labels remain firmly attached 1 Verify removing the auxiliary interlock INTLK AUX connector on the power supply prevents laser operation Interlock Connector Figure 2 3 The Power Supply Connector Panel 2 Verify the laser can only be turned on when the key switch is in the ON position and that the key can only be removed when the switch 1s in the off position 3 Verify the emission indicator provides a visible signal when the laser emits accessible laser radiation that exceeds the accessible emission limits for Class I 4 Verify the time delay between turn on of the emission indicator and
68. nterlock open 140 Controller interlock open 141 Communications error between head amp supply 142 System shut off check HST on info menu 143 System shut off pwr sply interlock 144 System shut off head interlock 145 System shut off REMOTE interlock 146 System shut off power adjust timeout 147 System shut off current limit 148 Controller communications time out 200 Diode calibration required 201 Diode1 curr calib required 202 Diode2 curr calib required 203 Diode3 curr calib required 204 Diode4 curr calib required 205 Diode1 temp calib required 206 Diode2 temp calib required 207 Diode3 temp calib required 208 Diode4 temp calib required Notes Notes 1 Millennia V Diode Pumped CW Visible Laser Notes 2 Notes Notes 3 Millennia V Diode Pumped CW Visible Laser Notes 4 Notes Notes 5 Millennia V Diode Pumped CW Visible Laser Notes 6 Report Form for Problems and Solutions We have provided this form to encourage you to tell us about any difficulties 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 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
69. o aid in bringing such problems to our attention Thank you for your purchase of Spectra Physics instruments Table of Contents LEE ee E E E lii Table OF CONIENIS ricas als ak T n aa o mee See V dE d ve CN IX Standard UNS ssa s UN PKK NS Ns xi Unpacking and Inspection slsh khh nn n nn es xiii Unpacking Your LaSer Jag is Die susi Oe Sie IS xiii System COMPONE MS e Tesan aai SO AE A A D xiii ACCESS AN ss ad He Aes Dee a xiii Chapter 1 Introduction x sus tie re a A 1 1 The Millennia Vi e Ve e EE 1 1 The Laser Systainer da A 1 2 re ele MEET 1 2 Bee Tee 22 2378 40202055 al UE ASA 1 2 El SER 1 3 Control MOdal lt ice ari e rs o BS ee Se a a 1 3 ENS AA A A ae 1 3 Chapter 2 Laser TEEN 2 1 Precautions For The Safe Operation Of Class IV High Power Lasers 000 ee L 2 1 Maintenance Necessary to Keep this Laser Product in Compliance with Center for Devices and Radiological Health CDRH Regulations o 2 3 CDRH Requirements for operation with the Control Module 2 4 Cover Safety IMENSEK so dra Bev ete head de eee ima iia Edad 2 4 Ke ale e MEET 2 4 POWER ee ENEE ENTREE 2 4 CDRH CE Radiation Control Drawing crre loss sk K n 2 6 CDRH CE Warning Ee 2 7 CE Declaration of Conformity Emissions n nanana aa aaea ae 2 8 CE Declaration of Conformity Low Voltage loss ksnk n ee eee eae 2 9 Sources for Additional Information esere siervissen as a ed a aa STN 2 10 Laser Safety Standards e cars dem
70. o not confuse it with the serial connector on the laser head which provides attachment for a terminal or computer Controls Indicators and Connections LASER HEAD connector 27 pin provides attachment for control lines from the umbilical Do not disconnect the umbilical connector Laser diode cable connectors 2 provides attachment for the armored fiber optic cables These cables are permanently attached to the diode mod ules Do not try to disconnect them Call Spectra Physics to have a service engineer replace the diodes when needed Power cord connector provides attachment for the twist on power cord provided with the unit Connect the cord to a power source capable of pro viding 15 10 A at 110 220 V Voltage select jumper terminal block provides a means for matching the system to the local power line Use a screwdriver to loosen the screws then position the jumpers according to the silkscreen for the voltage desired After making any adjustments verify the screws are tight Millennia V Diode Pumped CW Visible Laser Chapter 5 Laser Installation Note i Installation and Alignment With the exception of the vertical and horizontal controls of mirror Mg there are no internal controls to adjust or optics to change This makes the Millennia V laser very easy to set up and operate The following instruc tions will get you operational in a very short time When you received your laser it was packed with the laser h
71. od a Hold the fiber so that the coated surface is facing upward and place a sheet of lens tissue over it b Sgueeze a drop or two of methanol onto it and slowly and steadily draw the tissue across the surface to remove dissolved contami nants and to dry the surface Repeat as necessary using a clean tis sue each time 2 Forstubborn contaminants use a tissue in a hemostat to clean the fiber end a Fold a piece of tissue in half repeatedly until you have a pad about 3 to 4 mm wide trim with clean forceps if necessary and clamp it in a plastic hemostat Figure 7 1 b Saturate the tissue with methanol shake off the excess resaturate and shake again c Gently wipe the surface in a single motion Take care as you wipe the surface as this method applies more stress to the coatings and can if done too roughly or too often damage the fiber ends Also be careful that the hemostat does not touch the optical surface or the coating may be scratched d Inspect the cleaned surface to verify the optic actually got cleaner 1 e that you did not replace one contaminant with another e Replace the fiber bundle into the Z head It 1s not advisable to cap or leave exposed any fiber ends that have been cleaned This only invites further contamination and further cleaning Cleaning must be held to a minimum to prevent stress to the coatings and the fiber itself This concludes the procedure for cleaning the fiber optic bundle
72. odes typically hundreds e small signal gain e gain saturation e nonlinear conversion e excited state lifetime and e cavity lifetime to enable the Millennia V to use intracavity doubling with the simplicity of a single linear cavity design The result is a high power multiaxial mode laser that exhibits extremely low noise performance with very high reliabil ity and a doubled beam that has a smooth intensity distribution and is near diffraction limited 3 13 Millennia V Diode Pumped CW Visible Laser The Beam Delivery Arm The beam delivery arm Figure 3 10 controls the output beam parameters and modifies it to resemble that of a small frame ion laser A dichroic out put coupler allows the 532 nm light to exit the cavity while reflecting the 1064 nm light back into the cavity The 90 polarization rotator aligns the polarization axis vertically to match that of most small frame argon ion lasers A telescope expands the 532 nm output beam to match the beam size and propagation parameters to those of an argon ion laser This ensures optimum performance when the Millennia V is used to pump a Spectra Physics Tsunami mode locked Ti sapphire laser a Model 3900S cw Ti sap phire laser or a Model 375B dye laser Unlike other systems that reguire multiple feedback loops to maintain sta ble output the Millennia V is inherently stable within its operating range It requires only one simple feedback loop to maintain its except
73. of the nucleus in a double lobed configuration Figure 3 1 The energy of an electron 1s determined by the orbital that 1t occupies and the over all energy of an atom its energy level depends on the distribution of its electrons throughout the available orbitals Each atom has an array of energy levels the level with the lowest possible energy is called the ground state and higher energy levels are called excited states If an atom is in its ground state it will stay there until it is excited by external forces Movement from one energy level to another a transition happens when the atom either absorbs or emits energy Upward transitions can be caused by collision with a free electron or an excited atom and transitions in both directions can occur as a result of interaction with a photon of light Con sider a transition from a lower level whose energy content is E to a higher one with energy E It will only occur if the energy of the incident photon matches the energy difference between levels 1 e hv E E 1 where h is Planck s constant and v is the frequency of the photon Light will be used to describe the portion of the electromagnetic spectrum from far infrared to ultraviolet 3 1 Millennia V Diode Pumped CW Visible Laser Population Inversion 3 2 Figure 3 1 Electrons occupy distinct orbitals that are defined by the probability of finding an electron at a given position the shape of the orbita
74. 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 Unless otherwise specified all parts and assemblies manufactured by Spectra Physics are unconditionally warranted to be free of defects in workmanship and materials for a period of one year following delivery of the equipment to the F O B point Liability under this warranty is limited to repairing replacing or giving credit for the purchase price of any eguipment that proves defective during the warranty period provided prior authorization for such return has been given by an authorized representative of Spectra Physics Spectra Physics will provide at its expense all parts and labor and one way return shipping of the defective part or instrument if reguired In warranty repaired or Millennia V Diode Pumped CW Visible Laser replaced equipment is warranted only for the remaining portion of the orig inal warranty period applicable to the repaired or replaced equipment This
75. on the next page Laser Head Output End Emission Interlock Indicator Switch Shutter Emission Indicator Auxiliary Interlock Freguency Switch Voltage Select Jumpers On Off Button T40 Power Supply Power Cord Connector Figure 2 5 CE CDRH Radiation Control Drawing 2 6 Laser Head Output End Laser Head Rear Panel On Off Button Emission Indicator Control Module Laser Safet CE CDRH Warning Labels VISIBLE AND OR INVISIBLE LASER RADIATION IS EMITTED FROM THIS APERTURE SEE MANUAL Been A VISIBLE AND INVISIBLE DO NOT REMOVE LASER RADIATION WHEN OPEN AND INTERLOCK DEFEATED AVOID EYE OR SKIN EXPOSURE TO DIRECT OR SCATTERED RADIATION SEE MANUAL SEE MANUAL LASERSTRAHL FFNUNG LASER APERTURE AVOID EXPOSURE A CDRH Aperture Label 1 CE Aperture Label 2 CE Aperture Label Fiber optic Cable 3 CE CE Certification Label 4 VISIBLE AND OR INVISIBLE LASER RADIATION NON INTERLOCKED AVOID DIRECT EXPOSURE TO BEAM C 0 UPLIN G CONSULT INSTRUCTION MANUAL CLASS IV LASER PRODUCT CDRH Danger Label CDRH Danger Label CDRH Danger Label Interlock Defeated 5 Fiber Cable Side A 6 Fiber Cable Side B 6 VISIBLE AND OR INVISIBLE VISIBLE AND OR INVISIBLE F1 F2 F3 LASER RADIATION LASER RADIATION VOLTAGE 3AG TYPE T UL198G AVOID EYE OR SKIN EXPOSURE TO AVOID EYE OR SKIN EXPOSURE TO DIRECT OR SCATTERED RADIATION DIR
76. ontal Adjust Vertical Adjust RS 232 Serial Port Connector 9 pin Controller Connector 15 pin Umbilical Attachment Figure 5 1 The Millennia V Laser Head Rear Panel If a remote host system is to be used to control the Millennia V laser refer to the end of Chapter 6 Operation The RS 232 Serial Port for informa tion on wiring and connections baud rate command language etc 5 2 Installation and Alignment Installing the Power Supply Installing the Chiller Warning W 1 Place the power supply in a convenient location within 3 m of the laser head the length of the umbilical cable 2 Verify the cable connections from the umbilical are still tight The REMOTE SERIAL COM and LASER HEAD connectors should never be disconnected from the power supply panel If for some reason they do get disconnected take care to reconnect them Each plug has a dif ferent number of pins so they cannot be swapped Tighten the retaining screws when you are done 3 Verify the interlock jumper is in place or if desired remove it and add a non jumpered connector and wire it to a safety switch The switch must be wired so that when the device is actuated e g a door 1s opened the switch opens and the laser turns off 4 Verify the voltage selection jumpers are correctly set to match the volt age In your area To change the setting simply loosen the screws and move the jumpers to the proper setting Refer to the si
77. ordingly This completes the output optimization procedure 6 9 Millennia V Diode Pumped CW Visible Laser Turning Off the Laser 5 Note Once Millennia V output is optimized we suggest you leave the unit in Standby mode when not in use 1 e turn the laser off but leave the power supply power switch in the on position at all times This reduces warm up time and keeps the SHG crystal at optimum operating temperature To turn off the laser simply l 2 3 Press the LASER POWER button to turn off the laser Turn the key switch on the power supply to OFF and remove the key to prevent unauthorized use Leave the power switch on the power supply in the on position If Standby mode has been activated the system will go to Standby mode automatically after the preset delay time This is the preferred off mode for day to day operation If you are not going to use the laser for an extended period of time turn off the power supply com pletely Turn off the chiller This completes the turn off sequence Setting the SHG Crystal Temperature 6 10 We strongly recommend you do not change the temperature of the SHG doubling crystal There are however a very few instances where this might be appropriate and the following information is provided for use in those rare cases To change the SHG crystal temperature ie pa Select the Setup menu Place the system in current mode and set it for
78. over an area cov ered by a soft lint free cloth or pad e Wash your hands thoroughly with liquid detergent then put on finger cots before touching any optic Body oils and contaminants can render otherwise fastidious cleaning practices useless e Use filtered dry nitrogen canned air or a rubber squeeze bulb to blow dust or lint from the optic surface before cleaning it with solvent Per manent damage can occur if dust scratches the glass or mirror coating e Use spectroscopic electronic or reagent grade solvents Don t try to remove contamination with a cleaning solvent that may leave other impurities behind Warning u Maintenance Since cleaning simply dilutes contamination to the limit set by solvent impurities solvents must be as pure as possible Use as little solvent as possible as any solvent evaporates it leaves impurities behind in pro portion to its volume Avoid rewiping a surface with the same swab a used swab and solvents will redistribute contamination they will not remove it e Store methanol and acetone in small glass bottles These solvents collect moisture during prolonged exposure to air Avoid storage in bottles where a large volume of air is trapped above the solvent e Use Kodak Lens Cleaning Paper or equivalent photographic clean ing tissue to clean optics e Use each piece of tissue only once dirty tissue merely redistributes contamination it does not remove it Do not use
79. ower right corner either increase or decrease the value displayed on the screen such as the power setpoint or allow you to select or change a parameter from a list on the display 6 1 Millennia V Diode Pumped CW Visible Laser The Menu System 6 2 The LCD screen displays several things but what 1s displayed depends on the menu in use The large digits always display actual output power and below that in smaller text is either the output power setpoint when power mode is selected or the percentage of maximum current when current mode is selected RS 232 ENABLED is shown if the system is being oper ated remotely via the serial link In general use e the Main menu to monitor output power and to set the power or current setpoint the desired output e the Setup menu to select power or current mode to activate or deacti vate standby mode and to set its delay time before activation to set Main menu power setpoints P1 and P2 and to select local or RS 232 control of the system RS 232 commands are listed at the end of this chapter e the Info menu to view the diode drive current the temperature for each laser diode the temperature status of the SHG doubling crystal and the revision level of the Millennia V software Also included is a history HST line that shows the last three system error codes Refer to the following sections for more information on each menu Four menus Main Setup Standby and Information
80. 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 Millennia V Diode Pumped CW Visible Laser Appendix A Status Codes Listed below are all the status codes and messages that might be displayed on the controller not the Model 140 power supply while using the Millen nia V system Most codes are self explanatory and most errors can be cor rected by the user In the event the error cannot be corrected or the action required to correct the error 1s not known call your Spectra Physics service representative Before calling however write down the code and message Code 0 to 126 are generated by the Model T40 power supply codes 127 and up are generated by the Millennia V laser head Codes 142 to 147 are latched interlock messages that indicate the Model T40 shut off without a command to do so These latched interlock messages are cleared by either a pressing the LASER POWER switch on the controller or b sending the OFF command through the RS232 port The Info menu HST line on the controller lists the three most recent status codes with the most recent listed first The RS232 H query reports the most recent 16 codes again with the most recent listed first Code Message 0 Everything is fine Power Mode Ready 2 Current Mode Ready 3 Power Mode Adjust 4 Current Mode Adjust 5 Diodes off temperature stable ready to
81. plitude Virtually all the doubled light passes through the dichroic output coupler M where the beam is then expanded and directed out of the laser A beam splitter and photodiode sample the output and provide feedback to the pump diode drivers to provide a constant output in power mode operation The Millennia V Laser Head The Z head 3 12 The laser head is designed for maximum reliability with minimum com plexity All resonator components are rigidly attached to a solid L shaped resonator and the entire intracavity beam path is enclosed for maximum stability and prolonged hands off operation The inherent operation is so stable and the output so quiet that no adjustments are needed for normal operation Control of the entire system is provided via a simple menu driven control module Three major components comprise the laser head Figure 3 10 e Z head e Frequency doubling arm e Beam delivery arm The Z head is a compact fully enclosed module that is so named for the beam path within it see Figure 3 11 It contains the neodymium yttrium vanadate Nd YVO laser crystal which is the driving engine of the Mil lennia V laser The crystal is end pumped by two fiber coupled diode bar FCbar modules and provides a very high cw small signal gain It is capa ble of producing over 10 W of near diffraction limited 1064 nm infra red power with a conversion efficiency greater than 50 As shown in the figure the outputs f
82. r 200 Constitution Avenue N W Room N3647 Washington DC 20210 Tel 202 693 1999 A Guide for Control of Laser Hazards 4 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 One Tech Drive Andover MA 01810 2452 Tel 310 445 4200 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 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 Dr
83. r Optics and Optical Fibers 7 1 General Procedure for Cleaning Optics eee teens 7 3 General Procedure for Cleaning Fiber optic Bundles 7 5 Chapter 8 Service and Repair mai ad da ew aun ke ad ad ee neers 8 1 Troubleshooting GUS aorta eka m al olde aed Sk RE Ee EE 8 1 Sieten EEN 8 4 Chapter 9 Customer Service 0000 nn nn nn nn ees 9 1 CUSTOMER O VCO ecos kats eee Tees 9 1 VATKAIN 28d Dr EK 9 1 Return of the Instrument for Repair o oooooooooo ee eee ees 9 2 SENICE Centers ada ky diia pe dr a A Zeeche dE 9 3 Appendix A Status Codes ococcococc ees A 1 Notes Report Form for Problems and Solutions Vii Millennia V Diode Pumped CW Visible Laser List of Figures Figure 1 1 The Millennia V System o oooooooono n 1 1 Figure 2 1 These CE and CDRH standard safety warning labels would be appropriate for use as entry warning signs EN 60825 1 ANSI 4 3 10 1 loss ksnk ees 2 2 Figure 2 2 Folded Metal Beam Target ollu ccc N N 2 2 Figure 2 3 The Power Supply Connector Panel 0 00 eee eee 2 3 Figure 2 4 Laser Head Emission Indicator Shutter and Safety Interlock 2 5 Figure 2 5 CE CDRH Radiation Control Drawing ss soks eee eee nee 2 6 Figure 2 6 CE CDRH Warning Labels 2 7 Figure 3 1 Electrons occupy distinct orbitals that are defined by the probability of finding an electron at a given position the shape of the orbital being de
84. rared Excited electrons quickly drop to the F level the upper level of the lasing transition where they remain for a relatively long time about 60 us for Nd YVO E 20 Pump Bands 18 16 Tas 11502 cm Ro A P 8 A yy Laser ta a Transition 10 Laser Tas Transition NN 6000 cm 1 8 T 4 4F 3 9 SE 4000 cm 1 6 aN 2526 2a 4F a 2473 4 a _ 2146 SE 10 2029 2 2001 848 EE s 197 Ground Level S Figure 3 4 Energy Level Scheme for the Nd Ion The most probable lasing transition is to the fz state where a photon at 1064 nm is emitted Because electrons in that state quickly relax to the ground state its population remains low Hence 1t is easy to build a popula tion inversion At room temperature the emission cross section of this tran sition is high so its lasing threshold is low While there are competing transitions from the same upper state most notably at 1319 1338 and 946 3 5 Millennia V Diode Pumped CW Visible Laser nm all have lower gain and a higher threshold than the 1064 nm transition In normal operation these factors and wavelength selective optics limit oscillation to 1064 nm Diode pumped Laser Design 3 6 Laser diodes combine very high brightness high efficiency monochroma ticity and compact size in a near ideal source for pumping solid state lasers Figure 3 5 shows the monochromaticity of the emission spectra of a laser diode compared to a kryp
85. rom the two pump diode modules in the power supply are fiber coupled into the Z head and focused into each end of the Nd YVO laser crystal The diode pump light is absorbed by the crystal and emitted as output at 1064 nm The 1064 nm output is resonated in the Millennia V cavity and amplified through stimulated emission Laser Description l FCbar fiber delivery bundle Cavity end mirror HR 1 064 um Z head Body Nd YVO4 gain media Focusing Lens Assemblies Cavity fold dichroic mirrors HR 1 064 um FCbar fiber delivery bundle Figure 3 11 The Z Head top view The Frequency Doubling Arm As 1ts name implies the frequency doubling arm Figure 3 10 converts the 1064 nm light from the laser crystal to the green 532 nm light that becomes the output of the laser For maximum intracavity frequency doubling conversion efficiency a non critically phase matched temperature tuned LBO crystal is used It offers a large acceptance angle which makes it insensitive to any slight misalign ment of the Millennia V cavity A small low power temperature regulating oven 1s used to maintain the crystal at the appropriate phase matching tem perature to keep the 532 nm power optimized QMAD Quiet Multiaxial Mode Doubling technology patent number 5 446 749 allows the Millennia V to provide greater than 5 watts of excep tionally stable low noise freguency doubled light It provides a stable bal ance of e avery large number of axial m
86. s Millennia V Diode Pumped CW Visible Laser Chapter 8 Service and Repair Danger The Spectra Physics Millennia V laser is a Class IV High Power Laser AK whose beam is by definition a safety and fire hazard Take precautions to prevent accidental exposure to both direct and reflected beams Dif fuse as well as specular beam reflections can cause severe eye or skin damage Always wear proper eye protection when working on the laser and follow the safety precautions in Chapter 2 Laser Safety This troubleshooting guide is for use by you the user It is provided to assist you in isolating some of the problems that might arise while using the system A complete repair procedure is beyond the scope of this man ual For information concerning the repair of your unit by Spectra Physics please call your local service representative A list of world wide service sites 1s included at the end of Chapter 9 Before you call note your current software revision number 1t can be found on the Info Menu by scrolling to the bottom of the list of specifications that are displayed on the screen Troubleshooting Guide Symptom The controller screen does not light up Possible Causes Corrective Action Power is not available to the If the power supply fan is off system a verify that the power cord is plugged in b verify the voltage selector is set to the correct line voltage c verify the internal voltages are correct call yo
87. shes a statement to this effect or an indicator on the control equipment 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 control panel that affects laser output Cover Safety Interlock Laser Head Danger Laser Radiation Power Supply 2 4 The Millennia V system has a safety interlock for the laser head cover only Removing this cover turns off the laser diodes The cover must be on or the interlock defeated before the laser will operate Installing the safety interlock key in the laser head allows the laser to oper ate with its cover removed refer to Figure 2 4 Collateral radiation While the laser head cover is removed be extremely careful to avoid exposure to laser or collateral radiation The laser head cover cannot be replaced until the safety interlock key has been removed Shut off the laser before removing the interlock key and replacing the cover Because there are no user serviceable parts inside the power supply or internal adjustments that can be made by the user the Millennia V Model T40 power supply requires no cover safety interlock switch Laser Safet Emission Shutter Safety Interlock Key Indicator Interlock Holder Figure 2 4 Laser Head Emission Indicator Shutter and Safety Inter lock Millennia V Diode Pumped CW Visible Laser CE CDRH Radiation Control Drawing Refer to the CE CDRH Warning Labels
88. should never be disconnected if they were refer to Chapter 5 Installation and Alignment for instructions on re comnecting them Turn on the power supply power switch Turn on the chiller Verify 1t 1s set to 18 C Refer to the chiller user s manual for instructions Turn on the power supply key switch Power Supply Start up As the system starts up the following message sequence is displayed on the power supply LCD screen Spectra Physics followed by the software version number System Initializing Bypass delay time Laser Diodes Off Status Wait Cooling System Test Diode Safety Check If the key switch 1s not set to ON the system will not start up and the following 1s displayed on the panel System Error Open Interlock Simply set the switch to ON to clear the error message and enable the system Adjusting Temperature This message remains on screen until the laser diodes are at operating temperature At this time the Warm up menu is displayed on the con troller Boot Complete Laser Diodes Off Power Mode Ready This is the final display from the power supply which indicates it is ready for use Controller Start up The following message seguence is displayed on the controller as the sys tem turns on Spectra Physics Welcome to the new Millennia V Operation After the welcome message the system begins the warm up cycle
89. starting of the laser it must give enough warning to allow action to avoid exposure to laser radiation 5 Verify the beam attenuator shutter actually blocks access to laser radiation 6 Verify the safety interlock stops emission of laser or collateral radia tion upon removal or displacement of the interlocked laser head cover 7 When the safety interlock is defeated verify the defeat key is clearly visible and that it prevents replacement of the cover 0 39 uW for continuous wave operation where output is limited to the 400 to 1400 nm range 2 3 Millennia V Diode Pumped CW Visible Laser CDRH Requirements for operation with the Control Module The Millennia V laser head and the Model T40 power supply comply with all CDRH safety standards when operated with the Millennia V control module However when the laser is operated through the serial interface 1 e without the control module you must provide the following in order to satisfy CDRH regulations e A key switch that limits access to the laser and prevents it from being turned on It can be a real key lock a removable computer disk a pass word that limits access to computer control software or a similar key implementation The laser must only operate when the key 1s present and in the on position 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 fla
90. t of a laser diode bar into a multimode optical fiber The results have been discouraging so far with coupling efficiencies on the order of 60 70 with a numerical aperture of 0 4 This makes for an expensive inefficient pump source At Spectra Physics we have developed and patented a vastly more efficient method of fiber coupling the output of the laser diode bar It is called FCbar M With this method it is possible to achieve coupling efficiencies in excess of 90 with a numerical aperture of 0 1 With such high coupling efficiency and brightness high power diode pumped laser designs are readily achieved Millennia V Diode Pumped CW Visible Laser Frequency Doubling 3 8 In the Millennia V the high output power from the laser diodes is used to end pump the Nd YVO lasing medium The resulting 1064 nm output is converted to the visible through frequency doubling or second harmonic generation in a nonlinear crystal The Millennia V uses a 90 non critically phase matched temperature tuned lithium triborate LBO nonlinear crys tal as 1ts doubling medium Although LBO has a lower nonlinear coefficient than other materials 1t offers several advantages a non critical phase matching means collinear fundamental and second harmonic beams which facilitates alignment b there is no spatial walk off of the fundamental and second harmonic beams which preserves the high spatial mode quality and favors a long interaction length for
91. termined by the radial and angular dependence of the probability oo knn 3 2 Figure 3 2 A Typical Four level Transition Scheme sos kkk cee ees 3 3 Figure 3 3 Frequency Distribution of Longitudinal Modes for a Single Line 3 4 Figure 3 4 Energy Level Scheme for the NdP on 3 5 Figure 3 5 Nd9 absorption spectra compared to emission spectra of a Black Body Source a Krypton Arc Lamp b and a Laser Pump Diode ich 3 6 Figure 3 6 Mode MACNING WEE 3 7 Figure 3 7 The quiet multiaxial mode doubling QMAD solution to the green problem a The green problem Intracavity frequency doubling in a laser with a few axial modes produces large amplitude fluctuations in the second harmonic output resulting from nonlinear coupling of the modes through sum frequency mixing b The single frequency solution forces oscillation on a single axial mode to eliminate mode coupling c The QMAD solution produces oscillation on many axial modes effectively averaging the nonlinear coupling terms to provide highly stable second harmonic output 3 9 Figure 3 8 The Millennia V System 3 10 Figure 3 9 Schematic of the Millennia V Laser Head 3 11 Figure 3 10 Schematic of the Millennia Laser Head 3 11 Figure 3 11 The Z Head top view 3 13 Figure 3 12 Outline Drawings scsi 6 2402 Keene 8 Ee eee AAA a eee OS 3 16 Figure 4 1 The Millennia V Laser Head 4 1 Figure 4 2 The Mi
92. the current setpoint as a percentage of maximum current when the system is set for current mode or RS 232 ENABLED when the system is operated remotely via the serial link The left figure below shows the power mode display current mode is shown on the right When the system is tracking correctly in power mode the two num bers actual output power and setpoint are the same 0 01 W Setup Setup Info Info P1 m m P2 Set 0 20W Set 39 1 To change the power or current setpoint either press one of the preset power setpoint keys P1 or P2 to move directly to a preset power set in the Setup menu or use the up down buttons to set a new value Note that when the buttons are held down the setpoint numerical update pauses from time to time This is normal To change from power to current mode or vice versa use the Setup menu If an error occurs ERROR flashes in the lower left corner of the Main menu Press the lower left button to display the error source Error codes and their definitions are listed in Appendix A When the problem is cor rected the ERROR message turns off If the error code is generated by the power supply it is logged on the history HST line in the Info menu Menus available from the Main menu are e Setup e Info Use the Setup menu to change between power and current mode to activate or deactivate Standby mode and to set its time delay before activation to set Main menu preset pow
93. the desired output power Press the 2 lower left selection buttons at the same time The following is displayed Main SHG Adj RESET SHG Adj 35 Use the up down keys to change the temperature count Temperature is given as 127 counts from a nominal setting The sys tem is shipped from the factory at a calibrated setting somewhere between 0 and 25 counts If you get into trouble press the RESET button to return the SHG doubling crystal to this factory temperature setting Operation 5 Press the MAIN button to leave the crystal adjust mode and return to the Main menu This completes the SHG crystal temperature set procedure The RS 232 Serial Port Pinout Wiring The Millennia V serial port is accepts a standard 9 pin D sub male female extension cable for hook up Only three of the pins are actually used Pin Numbers Usage 2 transmit data Millennia V out 3 receive data Millennia V in 5 signal ground Communications Parameters Communications must be set to 8 data bits no parity one stop bit using the XON XOFF protocol do not use the hardware RTS CTS setting in your com munications software The baud rate is variable and can be set to 1200 2400 4800 or 9600 default The rate is determined at system power up by reading positions 1 and 2 of switch S1 on the laser head pc board Figure 6 4 shows the location of the DIP switch on the pc board and the table below describes the fu
94. ton arc lamp and a black body source and compares that with the absorption spectra of the Nd ion The near perfect overlap of the diode laser output with the Nd absorption band ensures that the pump light is efficiently coupled into the laser medium It also reduces thermal loading since any pump light not coupled into the medium is ultimately removed as heat Nd3 Absorption APP EN i E ie 0 5 0 6 0 7 0 8 0 9 Wavelength um Black Body gt D Source 3000 K S c be O 9 __ Krypton Arc Lamp LLI 0 5 0 6 0 7 0 8 0 9 gt Wavelength um KE Cc eb S S Laser Diode P Pump Wavelength E LLI 0 5 0 6 0 7 0 8 0 9 Wavelength um Figure 3 5 Nd gt absorption spectra compared to emission spectra of a Black Body Source a Krypton Arc Lamp b and a Laser Pump Diode c One of the key elements in optimizing the efficiency of a solid state laser is maximizing the overlap of the regions of the active medium excited by the pumping source and the active medium occupied by the laser mode The maximization of this overlap is often called mode matching and in most applications TEM is the laser mode that is most desired A longitudinal pumping geometry provides this sort of optimal mode match Laser Description Longitudinal pumping allows the diode output to be focused on a volume in the active medium that best matches the radius of the TEM mode In general the TEM mode radius is chosen to be as
95. turn on and the system output ramps to the most recently set power current OFF Turn Off Laser OFF lt CR gt 6 12 Note when the laser turns on 1t will be in the mode power current that was in effect when the unit was turned off Turns off the laser diodes and diode temperature reg ulation the latter reduces electrical power consump tion but the SHG crystal oven temperature 1s main tained for quick warm up time Latched interlocks are cleared Thirty minutes after the laser diodes have been turned off the system enters the Standby mode Operation P x x Set Power Sets laser output power to the nearest tenth watt if the unit has been previ ously set to power mode using the M command This command is ignored when the system is in current mode The minimum setting is 0 2 watts the maximum is 5 5 watts Commands outside this range are ignored P 5 lt CR gt Sets the output power to 5 0 W P 5 0 lt CR gt Sets the output power to 5 0 W no change P 4 9 lt CR gt Sets the output power to 4 9 W C xx Set Percent Current Sets the laser current to a percentage of maximum current if the unit has been previously set to current mode using the M command This com mand is ignored when the system is in power mode or when settings less than zero or greater than one hundred percent are reguested C 50 lt CR gt Sets both diodes to 50 current Mx Set Mode Sets the laser mode so that outp
96. ty Mirror M4 Mirror Mg Beam Path Figure 3 9 The Millennia V Laser Head Photodiode 90 Polarization Output Coupler E Rotator M EE S L asa El l Beam LBO Splitter Telescope EE d L Crystal HR M Beam Delivery Arm P Fiber ii lt Bundle Z Head Dichroic M X Telescope HR M Ke s Freguency SC Doubling Arm Nd YVO Gain Tor e H N 1 064 um Telescope RX 7 I XX Dichroic Mg Aperture HR M Jt OA Bundle Figure 3 10 Schematic of the Millennia V Laser Head Telescopes are used to focus the pump light through dichroic fold mirrors M and M and into the laser crystal where 1064 nm infrared intracavity light is generated M and M are highly transmissive at the diode pump wavelength and highly reflective at 1064 nm The aperture maintains the intracavity beam at a size that is optimal for beam overlap in the Nd YVO crystal thus ensuring efficient cavity light generation in the TEM mode 3 11 Millennia V Diode Pumped CW Visible Laser A non critically phase matched lithium triborate LBO crystal placed in the cavity near the high reflector mirror M converts the intracavity light to the green 532 nm wavelength The patented Quiet Multi Axial Mode Dou bling QMAD technique provides exceptionally low noise performance It uses a very large number of axial modes and balances gain nonlinear con version and excited state lifetime to provide high power and extremely sta ble am
97. ur Spectra Physics ser vice representative d verify the fuses in the power supply are not blown Power supply has failed Call your Spectra Physics service representative Symptom Low power Possible Causes Corrective Action Dirty optics Clean but do not remove the intracavity mirrors Do not attempt to clean the SHG crystal The beam is clipped Call your Spectra Physics service representative The chiller is not turned on or Verify the chiller is turned on Make sure all the water fittings are connected there is poor or no water flow Check the chiller for the correct water level Check the chiller s filter screen at the pump and clean it if necessary Refer to the chiller manual 8 1 Millennia V Diode Pumped CW Visible Laser Symptom Low power The SHG temperature is not Set the Millennia V to current mode 100 current Adjust the SHG tempera adjusted correctly ture for maximum output power For long term stability back the SHG count down by about 5 to 10 counts Adjust the HR for maximum output power The Millennia V is misaligned Set the Millennia V to current mode 100 current Adjust the HR for maxi mum output power Symptom High optical noise Possible Causes Corrective Action The SHG temperature is not Set the Millennia V to current mode 100 current Adjust the SHG tempera adjusted correctly ture for maximum output power For long term stability back the SHG count down by
98. ut is current regulated or power regulated The diode current or output power is ramped to the previous set value M1 lt CR gt Sets the laser to power mode MO0 lt CR gt Sets the laser to current mode Oueries P Get Power Status P lt CR gt Reguests the value of the laser output power in watts The response looks like 4 90 W lt LF gt 2Cx Get Diode Operating Current Status C1 lt CR gt Requests the value of the drive current for diode 1 Diode I C1 diode 2 C2 A typical response is 25 36A1 lt LF gt which is interpreted as 25 36 amps for diode 1 2M Get Mode Status 2M lt CR gt Requests system mode status The system responds with 1 lt LF gt for power mode or O lt LF gt for current mode 2SHGS Get SHG Oven Status SHGS lt CR gt Requests the status of the SHG oven The system responds S lt LF gt if the temperature is settled 1S lt LF gt if the oven is heating and 2S lt LF gt 1f it is cooling Values less than zero indicate an error such as a broken wire or loose cable 6 13 Millennia V Diode Pumped CW Visible Laser Table 6 2 Query Errors IDN Get Identification String IDN lt CR gt Reguests a system identification string The system returns an ASCII string that consists of four fields manufacturer product software revision number and serial number if the latter is not imple mented A typical return would be Spe

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