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MOPO FDO-970 - Spectra

1. PRINT type TotalLoops multiloop multiloopmax o Count WW WI WEND WHILE Count lt gt 0 Wait for last scan to finish IF DoWaits THEN GOSUB WaitFiveSeconds Cmd read count GOSUB WriteMopo GOSUB ReadMopo Count VAL Response Cmd read wlen GOSUB WriteMopo GOSUB ReadMopo Wl VAL Response PRINT type TotalLoops multiloop multiloopmax gt Count NG WI WEND RETURN WaitFiveSeconds Timel TIMER Time2 Timel D 27 MOPO FDO 970 WHILE ABS Timel Time2 lt 5 Time2 TIMER WEND SOUND 1000 3 SOUND 2000 2 RETURN Vk oec cec ce cce ck ce ce KK RK ce cce AK KK ck Ck kk ck ck Sk ck Ck ck ck ck ck ck ck Ck ck ck Ck ko ck ck ko ko Sk Ck ko ko ko ko ko SUB GpibError Msg STATIC PRINT GPIB PRINT Msg END SUB SUB MopoError Msg STATIC PRINT MOPO PRINT Msg END SUB D 28 Using the Optional RS 232 IEEE 488 Interface Connections Table D 1 RS 232 C Interface to PC Comm Port DTE RS 232 C DCE Device communications Link Device PC Computer gt MOPO FDO 25 Pin Standard 9 Wire 25 Pin connector Serial Interface Cable Connector f Protective Ground 1 7 Signal Ground 7 2 Transmitted Data 2 3 Received Data 3 4 Request To Send 4 5 Clear To Send 5 6 Data Set Ready 6 8
2. 000 cece ee eee eee 7 1 Troubleshooting Guide een een en nennen 7 1 Replacement Parts iio a BAL Re Se ee ea eh be Bate be ia a 7 9 Customer Service aes ig hare eid ce desk es m a Ro Re A RR E PU aa de 7 10 Lucus RE 7 10 Return of the Instrument for Repair eae 7 11 Service Centers london RE RR 7 12 Service Centers cont sers erdies rhe 7 13 Appendix A Installing a Software Upgrade eee eee eee A 1 Appendix B BBO Frequency Doubling Ladakas B 1 Appendix C Wavelengths vs Nominal Device Set Point C 1 Appendix D Using the Optional RS 232 IEEE 488 Interface D 1 SCOPE xo scende ars Pre du i e cert dut rera lace tas a e aged o POR D tall aad are bte dates atte D 1 OVENWIOW v sed zd ar petu ESSE eee debe id batan iei k ees D 1 Installation odo room d puma haa eR epe webs ati UE e d etui dub fete D 3 RHS 232 C Intefa cE ns ne recepte RR eere ee due at D 3 IEEE 488 Interface e reet HE Ole eR e RR EROR RR D 3 Selection RS232 IEEE LOCAL oooccccccccocc rr D 4 Saving Setup Parameters lh hh D 5 vi Table of Contents Initializatio s i Pb en ee xS ego tp bi ied e lala D 5 Procedure to Initialize the Interface llli D 5 Verification Test ossi inde ek a i asa I EE RE E PR Ee XI RE D 5 MOPO FDO Firmware Revision rre D 6 Format and Syntax Bules os ves pba obe bleue ERR de R Denn Diti ug D 6 A eeiam Ariki ag ia be da
3. Begin predetermined scan routine Figure 4 7 Initiating a Scan Figure 4 7 shows a scan being initiated from the Operate menu and the fol lowing procedure explains how to perform a scan in the FDO wavelength range It is similar to that used for the MOPO Before a scan can be performed there are parameters that must be set These are entered via the Scan Setup Menu see the previous section and refer to Figure 4 6 l 2 Press the SCAN SETUP button to access the Scan Menu Press the SCANS button to select this function then use the up down keys to set the number of scans you wish to perform In like manner set the scan BEGIN and END wavelengths If an incremental scan is desired set the SHOTS value to the number of shots required per dwell If a continuous scan is desired set the SHOTS value to O and set the scan rate the number under CONT in nm sec If an incremental scan was selected in step 4 set INCR to the number of nanometers desired between dwells Press OPERATE to return to the Operate Menu Press START SCAN to begin the scan process When the scan process begins the Operate Menu changes to indicate the progress of the scan refer to Figure 4 8 and to provide the opera tor control of the scan as it progresses A horizontal bar graph displays the percentage of scan completed and the wavelength displays show the progress of the doubled Signal or Idler output as well as the Signal or Idler output
4. 4 21 MOPO FDO 970 Of the five soft keys two remain present and become ABORT SCAN and HOLD SCAN Press the HOLD SCAN key to momentarily pause the Current Signal or Idler output scan Fraction of current scans complete Current FDO output 7 OPERATE OPERATE 239 624 SETUP SCAN an MONITOR E 477 248nm ABORT HOLD SCAN SCAN MONITOR el N Abort scan and return to Operate Menu Figure 4 8 Scanning in Progress 8 Once paused the HOLD SCAN key changes to RESUME SCAN Press this key to resume the scan 9 Press the ABORT SCAN button to return to the Operate menu When the scan completes the system moves to the starting wavelength Temporarily halt scan unless the ABORT key is pressed and returns to the Operate menu 4 22 Operation The MOPO Monitor Menu Relative GCR Pump Relative Master Osc Master Osc Select output power output power error correction MONITOR menu 0 to 100 0 to 100 tracking signal a N OPERATE 2 OPERATE SETUP mz Parad MONITOR 0 0 MOPO PUMP M OSC M OSC MONITOR POWER POWER TRK MONITOR e Fs Fo F3 Fy Fs L S Label only Label only Changes display gain Ch
5. C N OFERATE A OPERATE 230 000 M MONITOR 460 000nm 230 000 SCAN 0 0 MONITOR V F Fp F3 F Fs I E Soft Key Function Buttons Figure 4 1 Initial configuration of the electronics panel MOPO FDO 970 The SSS Select Scroll Set Procedure When operating the MOPO FDO use the select scroll set or SSS pro cess to select an operation scroll though various options upon which to operate or to change the value of the selected operation and then set that value or option to lock it in To do this press the appropriate function key to select the type of operation to be performed then use the up down keys to scroll through the options or values then set that selection to lock 1t in by pressing and holding in the original select button until 1t beeps For example if you wanted to Y shift the calibration table for the 56 crys tal you would first select the 56 crystal as the device upon which to be operated from the FDO Service menu which is covered later in this chap ter then select Y DISP as the function operator To do this press the DEVICE function key F4 to highlight it Next use the up down keys to scroll to 56 CRYS Finally press the DEVICE button again and hold it in until it beeps to set the 56 crystal as the selected device In the same man ner use the SSS process to select the Y DISP function press the METHOD key Fo to select it then use the up down keys to scroll to
6. PRINT Increment Increment Response6 PRINT Shots Shots Response4 PRINT Scans scans Response5 PRINT IF faultflag 1 THEN PRINT Incremental Scan Setup ERROR PRINT Program Terminated END END IF INCREMENTAL SCAN Cmd scan GOSUB WriteMopo PRINT Incremental scan running PRINT type Incr GOSUB WaitForScan SAVE AND RECALL PRINT Saving parameter setup TotalLoops total loops PRINT Cmd save 3 Save current operating parameters into non volatile memory as setup record 3 GOSUB WriteMopo PRINT Recalling parameter setup TotalLoops total loops PRINT D 24 Using the Optional RS 232 IEEE 488 Interface Cmd recall 4 GOSUB WriteMopo GOSUB WaitFiveSeconds Load setup parameters record 4 from non volatile memory are interrupts dead during read routinely hangs w o this wait NEXT multiloop GOTO TotalLoop makes an infinite loop program PRINT End of Sample Program END End of Sample Program NK KKK KKK KKK KK KKK KKK KEK ce kk ck AK KK KH KH KK ko ck ck ko ck ck ck ck ck ck ck ck Ck ck ck Ck ko ck ck ck ko ck Ck ko ko ko ko Ao li SU BROUT N ES Vk oec ck ce ck ce c ck ce kc ck ce kk ck AK KK KH Ck kk ck ck ko ck Ck ck Sk ck ck ck Sk Ck ko ck Ck ko ck ck ko ko ck Ck ko ko ko kx Ax x ReadSetup PRINT Verifying setup PRINT Cmd sour
7. 4 11 The MOPO Service Menu asaan a p Ee hmm 4 13 The FDO Servico Menu 424 ia kursa e meu NANG ae A E Ee Rd c eere 4 14 The Scan Setup Men e hrte by a le pea aed br mot 4 18 Running an EDO Scan ede hp ka ae S RE sa MEA tarada e RICE 4 20 The MOPO Monitor Menu sssssse e m mmm 4 22 The FDO Monitor Menu css e risus lem meer 4 24 The Remote Menu ur cese Roel A RED e RR ARENA PI pU EM HE 4 26 Switching Between MOPO and FDO Operation een 4 28 Switching from MOPO to FDO Operation nn 4 28 Switching from FDO to MOPO Operation 000 eee ren 4 28 Preparing the System for Scanning 22 ees 4 29 Scanning Wavelengths Above 366 NM 2 ees 4 29 Scanning Wavelengths Below 345 mm 4 ees 4 29 Operating at Fixed Wavelengths 0 0 00 hh 4 30 EDO Table Writing esee ar A eer uei Disp eu Nae ed EP Re Vna 4 30 Chapter 5 FDO Alignment 220 e eee eee en nnn n 5 1 Quick Start Procedure suci p do Eee ERE re e Ren aue x s 5 1 General Procedure iiag areis a aaea eee hh 5 1 Chapter 6 Maintenance oooooooocccccr eee 6 1 Preventive Maintenance lille hh f n 6 1 Glea ing Laser Optics erede BAGA hap a nG REA ERAN he ge cpu exu Ub EE 6 1 Cleaning Optical COMpoOnentS oooococ ehh 6 3 Equipment Required i2 scie etr s UR IRR SEE CEDERE ERE 6 3 Cleaning Prisms Crystals and Mirrors Lk aaa kaka 6 3 Chapter 7 Service and Repair
8. D nam Y Nh A koa MN 0 i pp Sample Prism a 1 and 1 Motor Mike 4 Hold Drive 56 Crystal MOPO Doubler Control Board FDO PC 36 Crystal Controller gt Motor Mike a Crystal i Motor Mike SS gt Drive e Pos Sensor MOPO Input Beam Figure 1 6 Electronics Interconnect Diagram 1 7 MOPO FDO 970 1 8 The crystal and prism drive circuits are dc servos DC motor driven micrometers are used to rotate the optics and linear potentiometers sense the angular positions and feed back an appropriate signal to close the loop Command analog voltages that represent the angular positions of these devices are summed with the sensor control voltages and thus close the loop to provide drive and position control The angles that are required to set the crystals for doubling and to set the PB prism to steer the resulting beam are stored as look up tables Instruc tions for creating and modifying these tables are found at the end of chapter 4 They are also in the MOPO Instruction Manual chapter 6 section Vc The PB prism angle is always commanded from a look up table whereas the crystal angle can be commanded either from a table which finds an angle close enough for phase matching to create the desired doubled output wavelength or by using the closed loop tracking circuit which utilizes the bi cell detector for
9. DTE device to the MOPO FDO DCE device Con nection should be simple with no cross connections required MOPO FDO Serial Interface Parameters The parameter settings for the MOPO FDO serial interface are eight data bits one stop bit no parity Configure the parameters of your computer s serial interface to match these BAUD Rate The MOPO FDO serial interface baud rate can be set anywhere from 300 to 2400 bits per second Chapter 4 Operation describes how to set the BAUD rate For your convenience it is repeated below under Selection The IEEE 488 GPIB interface of the MOPO FDO system is configured as a talker listener device i e it can both send and recieve data Your com puter must also have talker listener and bus controller capabilities Use a standard GPIB cable to connect your computer GPIB interface to the MOPO FDO The GPIB interface of the MOPO FDO system includes a National Instru ments GPIB PC IVIIA interface card that is installed inside the MOPO FDO controller Figure D 1 at the end of this appendix shows the dip switch and jumper settings for this card The card is shipped with the default settings shown If you have an IBM PC compatible computer you will have to install a GPIB controller card in it There are many brands of GPIB controller cards and you may use any one of them that gives your computer GPIB controller capability If you use the National Instruments GPIB PC IIA interface card you
10. Data Carrier Detect 8 20 Data Terminal Ready 20 Signals of the communications link are named with respect to the DTE device D 29 MOPO FDO 970 D 30 Table D 2 RS 232 C Interface to PC AT Comm Port DTE RS 232 C DCE Device communications Link Device PC Computer SF RE TTTESE MOPO FDO 9 Pin PC AT 9 to 25 Pin 25 Pin connector Serial Interface Cable Connector shell Protective Ground 1 5 Signal Ground 7 3 Transmitted Data 2 2 Received Data 3 7 Request To Send 4 8 Clear To Send 5 6 Data Set Ready 6 1 Data Carrier Detect 8 4 Data Terminal Ready 20 Signals of the communications link are named with respect to the DTE device Using the Optional RS 232 IEEE 488 Interface PC Computer MOPO National Instruments National Instruments GPIB PC II IIA Card GPIB PC IIIA Card O O 1 0 o O 1 0 5 8 e 325 oMN NH 2 FAN 72 a Fa 5 Fs o CO ie m L O Oj IRQ7 L HMS O Oj IRQ7 EN 5 mu 6 Mc o o DRQ1 NM o o EN O DACK1 EN js oo EN oo EM oo EN oo o o DRQ3 STORYA 515 Dipswitch 6 6 DACK3 Dipswitch EBEN This side of the dip switch is depressed Figure D 1 IEEE 488 Dip Switch and Jumper Settings D 31 MOPO FDO 970 D 32 Notes Notes 1 MOPO FDO 970 Notes 2 Notes Notes 3 MOPO FDO 970 Notes 4 Notes Notes 5 M
11. EN faul IF Response2 IF Response3 lt gt Shots THEN scans THEN IF Response4 lt gt IF Response5 lt gt Rate THEN faultfl tflag 1 ag 1 tflag tflag faul faul PRINT SA Continuous Scan Setup multiloop multiloop PRINT TotalLoops TotalLoops PRINT PRINT Parameter Sent Received PRINT NGA g PRINT Begin ScanBegin Responsel PRINT End ScanEnd Response2 PRINT Rate Rate Response3 PRINT Shots Shots Response4 PRINT Scans scans Response5 PRINT IF faultflag 1 THEN PRINT Continuous Scan Setup ERROR PRINT Program Terminated END END IF CONTINUOUS SCAN PRINT 1 scan w of u Y multiloopmax D 13 MOPO FDO 970 PR PR type Cont GOSUB WaitForScan IncrScanSetup PR PR Scanl ScanEnd 375 multiloop Increment 2 Shots 100 scans 3 PRINT 1 source begin PRINT 1 source end PRINT 1 source incr PRINT 1 source shots PRINT 1 source scans INT Continuous scan running INT Begin 365 multiloop ScanBegin ScanEnd Increment Shots scans INT Setting up incremental scan of idler range INT n 2 nanometer steps 100 shots at each WL Make three passes INCREMENTAL SCAN SET
12. FDO 970 Customer Service Warranty 7 10 At Spectra Physics Lasers we take great pride in the reliability of our products Considerable emphasis has been placed on controlled manufac turing methods and quality control throughout the manufacturing process Nevertheless even the finest precision instruments will need occasional service We feel our instruments have excellent service records compared to competitive products and we hope to demonstrate in the long run that we provide excellent service to our customers in two ways first by provid ing the best equipment for the money and second by offering service facil ities that get your instrument repaired and back to you as soon as possible Spectra Physics Lasers 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 countries refer to the Service Centers listing located at the end of this section Order replacement parts directly from Spectra Physics Lasers For ordering or shipping instructions or for assistance of any kind contact your nearest sales office or service center You will need your instrument model and serial numbers available when you call Service data or shipping instruc tions will be promptly supplied To order optional items or other syste
13. Scans 2 Make two passes Cmd source begin STR ScanBegin GOSUB WriteMopo Cmd source end STRS ScanEnd GOSUB WriteMopo Cmd source rate STR Rate GOSUB WriteMopo Cmd source shots STR Shots GOSUB WriteMopo D 21 MOPO FDO 970 Cmd source scans STRS scans GOSUB WriteMopo CONTINUOUS SCAN SETUP VERIFICATION GOSUB ReadSetup faultflag 0 IF Responsel lt gt ScanBegin THEN faultflag 1 IF Response2 lt gt ScanEnd THEN faultflag 1 IF Response3 lt gt Rate THEN faultflag 1 IF Response4 lt gt Shots THEN faultflag IF Response5 lt gt scans THEN faultflag PRINT on Continuous Scan Setup multiloop multiloop of multiloopmax PRINT TotalLoops TotalLoops PRINT MER 2225292225 i PRINT Parameter Sent Received BRENT VS ome ne meo PRINT Begin ScanBegin Responsel PRINT End ScanEnd Response2 PRINT Rate Rate Response3 PRINT Shots Shots Response4 PRINT Scans scans Response5 PRINT IF faultflag 1 THEN PRINT Continuous Scan Setup ERROR PRINT Program Terminated END END IF Cmd scan GOSUB WriteMopo PRINT Continuous scan running PRINT type Cont D 22 Using the Optional RS 232 IEEE 488 Interface GOSUB WaitForScan IncrScanS
14. The Operate Menu The Operate menu Figure 4 2 appears when the system is first turned on From other menus pressing the OPERATE button at any time returns you to this menu Pressing it a second time brings up the MOPO Service menu A third push brings up the FDO Service menu Pushed one more time will return you to the Operate menu The Operate menu allows the operator to set the MOPO FDO wavelengths directly to initiating a scan to manually tune the wavelength output to recall one of 20 stored settings and to save the present settings as one of the 20 stored settings The Display The large number in the upper right hand box is the doubled output wave length The small number below it is the Signal or Idler wavelength that is being doubled The Function Keys F GOTO allows the operator to set the FDO output wavelength Simply press the GOTO button scroll to the wavelength value desired using the up down keys then hold the GOTO button in until it beeps to begin the opera tion 1 e to move the system to that wavelength Note that the value does not have to be set as required by the SSS procedure The MOPO is auto matically tuned for the proper Signal or Idler output and the FDO crystal is tuned to provide the output wavelength desired Unlike the SCAN and MOVE commands GOTO allows movement through the degeneracy range between 345 and 366 nm although there is no output F START SCAN initiates a scan between two wav
15. Wavelength VAL responses PRINT stb GOSUB readdata STB PRINT TotalLoops PRINT STB STB DoWaits THEN GOSUB WaitFiveSeconds read SCPI status byte VAL responses multiloop multiloopmax Wavelength Wavelength 1 WENI ContinScanSetup REM GOTO IncrScanSetup INT INT INT INT Setting up continuous scan of signal range TotalLoops TotalLoops MultiLoop multiloop Vk oko ck ecce ce ck ce ce KK TR ce kc AK KK ck C kk ck ck ko ck Ck ck ck ck ck ck ck Ck ck ck Ck ck ck ck ck KKK ko ck Ck ko ko Sk Ck ko ko KH kx Ax kx U Y Test scanning through signal range continuous Y This scan involves the crystal switch and should provide Y adequate torture of the system ScanBegin 220 multiloop Start at 220 000 nm ScanEnd 270 multiloop Stop at 270 000 nm Rate 1 100 picometers second Using the Optional RS 232 IEEE 488 Interface Shots 0 Continuous scan Scans 2 Make two passes PRINT 1 source begin ScanBegin PRINT 41 source end ScanEnd PRINT 41 source rate Rate PRINT 41 source shots Shots PRINT 41 source scans scans CONTINUOUS SCAN SETUP VERIFICATION GOSUB ReadSetup faultflag O0 lt gt IF Responsel lt gt ScanEnd THI ScanBegin THEN faultflag 1
16. and that it is optimized and operating properly As a general note for controller and or software problems as is the case with many computers or computer based systems reboot the controller shut it off and turn it back on as a first step to solving the problem This is often sufficient to provide full recovery Troubleshooting Guide Symptom Controller screen does not light up Possible Causes Corrective Action Power is not available to the system If the fan is off 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 your SPL rep Memory card is missing If the fan is on verify the PCMCIA card is correctly plugged into the motherboard refer to Figure A 1 Memory card fault Call the factory 7 1 MOPO FDO 970 Symptom System is on but there is no doubled light Possible Causes Corrective Action Pump light is not present Verify the GCR is operating Verify the correct output and wavelength is available from the MOPO Refer to the MOPO User s Manual The master oscillator in the MOPO is not running Verify the master oscillator is running Refer to the MOPO User s Manual The power oscillator in the MOPO is not running Verify the power oscillator is running Refer to the MOPO User s Manual No fundamental light is delivered
17. be removed MOPO FDO 970 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 Stick to the following principles whenever you clean any optical surface Remove and clean one optical element at a time If all of the optics are removed and replaced as a group all reference points will be lost making realignment extremely difficult Work in a clean environment over an area covered by a soft cloth or pad 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 Always wear clean finger cots or gloves when handling intracavity parts and optics Use dry nitrogen canned air or a rubber squeeze bulb to blow dust or lint from the surface before cleaning with solvent Permanent damage can occur if dust scratches the glass or mirror coating Use spectroscopic electronic or reagent grade solvents Don t try to remove contamination with a cleaning solvent that may leave other impurities behind WARNING Do not use lens tissue designated for cleaning eye glasses Such tissue contains silicones These molecules bind themselves to the optic coatings and can cause permanent damage Also do not use c
18. box is a label to indicate the bar graph above it The function key sets the screen gain to 1 2 4 8 or16x using the SSS pro cedure F FDO DIFF display box is a label to identify the bar graph above it the button provides no function Operation The Remote Menu Select REMOTE menu OPERATE OPERATE SETUP Cat REMOTE SELECT IEEE488 BAUD LOCAL 15 2400 MONITOR F4 Fa F3 F4 Fs M y Selects system Sets IEEE 488 Sets RS 232 control mode address BAUD rate Figure 4 11 Remote Menu The Remote menu Figure 4 11 is used to select the system control source The default is the front panel or LOCAL but it can be set so that the MOPO FDO can be controlled by a serial device such as a terminal or a personal computer configured as a terminal or an IEEE 488 control source Once set this becomes the default control source until changed again by you The Remote menu is accessed by pressing the MONITOR button three times The first time it is pressed from another menu the MOPO Monitor menu is displayed Pressing it a second time displays the FDO Monitor menu A third press displays the Remote menu and the MONITOR button label changes to REMOTE A fourth press returns the display to the MOPO Mon itor menu Appendix D Using the RS 232 IEEE 488 Interface provides a comple
19. can use the dip switch and jumper settings shown in Figure D 1 The GPIB device address of the MOPO FDO system is set at the factory to address 15 If this address conflicts with the address of another instrument on the GPIB bus select another GPIB address for the MOPO FDO Refer to Selection below for instructions on how to select another GPIB address MOPO FDO 970 Selection RS232 IEEE LOCAL Use the Remote menu to select the system control source The default set ting from the factory is the front panel or LOCAL but the setting can be changed so that the MOPO FDO can be controlled from a serial device such as a terminal or a personal computer configured as a terminal or an IEEE 488 parallel control source When one of the remote interfaces is the con trol source LOCAL is displayed in F to allow the user to return control to the front panel Before the RS 232 C or the IEEE 488 interface can be used it must first be selected and its parameters set from the Remote menu See chapter 4 Operation The Remote Menu 1 Press the MONITOR menu key until the Remote menu is displayed The MONITOR label changes to REMOTE and the SELECT IEEE 488 and BAUD functions are displayed in the display boxes F SELECT allows the user to set the control interface to IEEE 488 RS 232 or LOCAL F IEEE 488 allows the bus address to be set F4 BAUD allows the serial BAUD rate to be set 2 Set the address for the IEEE 488 in
20. cycles dictated by METHOD are complete SAVE is displayed Press SAVE until it beeps to save the entered data F ABORT cancels the current command and returns the system to the initial screen It does not return the FDO to the start position If the data entered must be deleted hold this button in until the DELETE button is displayed then hold the DELETE button in until it beeps Be sure this is what you want to do The entire user defined table associated with that device will be erased and will not be retrievable If DELETE was selected in error press the button momentarily to return to ABORT then press ABORT to return to the initial screen Operation The Scan Setup Menu Select SCAN SETUP mode FDO wavelength Signal or Idler output a N El OPERATE A OPERATE 230 000 SETUP SE MONITOR 460 000nm SCANS BEGIN END CONT SHOTS 101 225 000 260 000 0 0101 0 LT MONITOR V F F5 F3 F F5 X y No of scans Scan starting Scan ending Speed of scan No of shots for each to be performed wavelength wavelength to be performed wavelength Select O shots for continuous scan Figure 4 6 The Scan Setup Menu Press the SCAN SETUP button at any time to display this menu Figure 4 6 This menu allows the operator to set the number of scans to be performed as well as the starting and end
21. drive past the set value then return to normal computer control The 36 crystal is mixing the Signal plus the Idler input to pro duce 355 nm output Rewrite the Lagrangian table s for the 36 crystal to shift the crystal angles to higher values lower set point numbers if doubling Signal wavelengths or to lower values higher set point values if doubling Idler wavelengths Q switch sync signal is not present Verify the Q switch signal is present Change to internal sync e g 730DINT and see if the situation changes Check the cables MOPO FDO 970 Symptom No power reading on the FDO MONITOR menus but uv is exiting the MOPO enclosure Possible Causes Corrective Action The output pick off beam is not properly pointed into the photode tector Use a business card to verify the pick off beam is properly aligned to photodetector PD There is no Q switch Sync signal to the FDO Verify the Q switch sync cable from the GCR is attached to the Q SWITCH SYNC connector on the controller back panel If it is verify the signal is actually present o scope The 8 pin DIN cable connector at the photodetector is loose Verify it is properly connected The photodiode cable connection at J1 on the head pcb is loose Verify it is properly connected Symptom The photodetector seems to be overloaded the power bar is at maximum Possible Causes C
22. menu 3 Verify the FDO is set to TABLE mode 5 1 MOPO FDO 970 5 2 10 Go to 250 nm The controller should position the FDO for operation at 250 nm Turn down the GCR LAMP ENERGY control and if not already in place install TP onto its operating position in the FDO Reset the GCR LAMP ENERCY control for full operation and use the vertical and horizontal adjustments on TP to align the MOPO Signal and Idler beams through the center of the FDO crystals and PB Prism These adjustments should be performed while viewing the transmitted beam on the FDO beam block to locate the edges of the crystal aper ture Once the edges are located adjust TP to guide the beam through the best center position of the crystal Note If you are realigning the FDO following a change from MOPO to FDO operation merely fine tuning the vertical adjustment the lower right hand knob on TP may be all that is required to re optimize the system Using a white business card or other uv sensitive viewing card look for a uv beam in the vicinity of the output beam splitter pair just to the right of the beam block If no beam is seen try a Y DISP operation on the 56 crystal to approximately maximize the uv fluorescence on the viewing card Using Y DISP rotate the PB prism to achieve best centering through the output beam splitters and output prism Use the horizontal adjustment of TP and the vertical adjustment of the 3PA to achieve the best ver
23. nm between scan wavelengths increment scan only SOURCE RATE HHH Scan speed nm per sec for con tinuous scans SOURCE SCANS HHRHH Number of consecutive scans to be made in one scan operation SOURCE SHOTS 0 Continuous scan mode SOURCE SHOTS HHHH Number of shots to be taken at each wavelength incremental scan only Setup Queries Message Parameter being queried SOURCE BEGIN Initial scan wavelength SOURCE END Final scan wavelength SOURCE GOTO Goto wavelength number SOURCE INCR Step size in nm between scan wavelengths increment scan only SOURCE RATE Scan speed nm per sec for con tinuous scans SOURCE SCANS Number of consecutive scans to be made in one scan operation SOURCE SHOTS Continuous scan mode MOPO FDO 970 Operate Commands Message Operation EXEGOTO Execute a GOTO operation SCAN Execute a GOTO or SCAN opera tion ABORT Terminate a GOTO or SCAN opera tion RECALL Load setup parameters from non volatile memory SAVE 4 Store setup parameters to non vol atile memory Operate Oueries Message Status being gueried READ COUNT Current SCAN count READ POWER Power of the master oscillator READ WLEN Current wavelength position IDN SCPI ID string STB SCPI status byte Using the Opt
24. the Y DISP dis placement function then set it by holding the METHOD key in until it beeps The 56 CRYS and the Y DISP function will remain the active selections until manually changed by the operator Note that although many proce dures for the MOPO FDO use the SSS process not all require it For exam ple setting the scan parameters beginning end and number of scans requires the operator to simply select them they do not have to be set These requirements are explained later under the menu descriptions Powering Up the System 4 6 Turn on the power switch on the rear of the unit The system will first per form an internal diagnostics routine which takes about 10 seconds then the front panel lights up and the OPERATE menu is displayed At this point any of the menus listed below and shown in can be chosen LLL Operation The Menu Structure A brief overview of the controller s layout and functions is included here for your convenience The menus and commands that are necessary for operating the FDO are listed here and are very similar to those used to con trol the MOPO For MOPO menus and information on MOPO operation refer to chapter 4 of the MOPO manual The illustration below shows the three mode keys the buttons to the left of the display and the services that are available through them The following section give a brief description of the various menus that are displayed when these modes are selected and lis
25. the beam passes through three prism assembly 3PA where the hori zontally polarized light from the MOPO is rotated 90 to orient it properly for the two frequency doubling BBO crystals XTL and XTL gt and the Pel lin Broca wavelength selection prism PB The SPA also turns the beam 90 to route it toward these three optics The system uses a controller driven motormicrometer to automatically rotate one of the crystals to the proper phase matching angle for generating the requested output frequency The second crystal becomes the inactive crystal This is explained in greater detail under The FDO Crystals below The PB prism performs two tasks First it splits off the residual Signal and Idler beams and directs them to beam block BB where they are absorbed Secondly it routes the selected frequency doubled uv beam through beam splitters BS and BS to turning prism TP BS directs a small portion of the beam to the bi cell split detector as feedback for the crystal angle track ing system BS is mounted it so that its wedge faces the opposite that for BS and provides dispersion compensation Finally turning prism TP gt directs the uv beam through the output port Table 1 1 is an operation summary showing the relationship between the FDO output wavelengths the crystals that produce them and the crystal and prism motormicrometer relative set points The latter numbers are dis played on the FDO Monitor menu refer to chapter 4 t
26. to the FDO Verify turning prism TP is in place and that the beam is properly routed through the FDO The FDO crystal is not properly located Use the FDO Service menu to verify the crystal set point and actual reading are in approximate agreement The set point values should be within 1000 counts of the reference values listed in appendix D Service and Repair Symptom Current crystal value CRY is not equal 200 to its SET value or the prism value PRS is not equal to its SET value in the FDO Service menu Possible Causes Corrective Action The MANUAL NORM switch on the electronics pc board for either the crystal or the prism is not in the NORM position Set the switch es to the NORM position Motormike s not connected or wiring is open Verify wires are properly connected to the head board If they are then check for continuity TP22 to ground and TP13 to ground should read about 115 Q Alignment apertures are interfer ing with mechanical movement Verify all the apertures have been removed There is a sticky mechanism If there is no CRV or PRSV reading movement move the crystal and prism rotating tables by hand against the spring to see if the values change The normal value range for each device is 1000 crystal SET 23000 8000 prism SET 24000 Reboot the unit to see if it can clear itself Use manual motor drive circuits on the FDO control pcb to
27. 19 0 579 MOPO FDO 970 B 4 Wavelengths vs Appendix C Nominal Device Set Point Use the following table as a guide to verify that the set point values read from the Service menu for these four MOPO FDO devices are in general alignment for the MOPO and FDO wavelengths given Note that these val ues are approximate 100 and can only be used as a rough reference Val ues have been rounded to the nearest 50 for simplicity Table C 1 Wavelength vs Nominal Device Set Point Mor oe seid 36 Crystal 56 Crystal PB Prism 400 200 32800 na na na 410 205 29700 na na na 420 210 26500 na na na 430 215 23600 na na na 440 220 21000 na 2700 10500 450 225 18600 na 5750 11200 460 230 16400 na 8150 12000 470 235 14500 na 10150 12650 480 240 12700 na 11900 13150 490 245 11200 na 13500 13650 500 250 9800 na 14900 14250 510 255 8500 na 16250 14750 520 260 7400 na 17500 15100 530 265 6400 na 18650 15550 540 270 5500 2700 19750 15800 550 275 4700 4400 21500 16200 560 280 4000 5400 22650 16550 MOPO FDO 970 Table C 1 Wavelength vs Nominal Device Set Point MOOR FED UN eod 36 Crystal 56 Crystal PB Prism 570 285 3400 6300 16900 580 290 2800 7150 17200 590 295 2300 7950 17500 600 300 1900 8650 17750 610 305 1500 9350 18000 620 310 1200 10000 18200 630 315 900 10600 18350 640 320 700 11200 18550 650 325 500 11800 18800 660 330 350 12450 19050
28. 350 1 205 0 793 0 6500 0 3250 36 662 1 218 0 785 0 6600 0 3300 36 005 1 230 0 777 0 6700 0 3350 35 377 1 241 0 770 0 6800 0 3400 34 776 1 251 0 762 0 6900 0 3450 34 200 1 262 0 755 0 7000 0 3500 33 648 1 271 0 747 0 7100 0 3550 33 118 1 280 0 740 0 7200 0 3600 32 609 1 289 0 733 0 7300 0 3650 32 120 1 297 0 726 0 7400 0 3700 31 650 1 304 0 718 0 7500 0 3750 31 198 1 312 0 712 0 7600 0 3800 30 763 1 319 0 705 0 7700 0 3850 30 344 1 325 0 698 0 7800 0 3900 29 940 1 332 0 691 0 7900 0 3950 29 550 1 338 0 685 0 8000 0 4000 29 175 1 343 0 679 0 8100 0 4050 28 813 1 349 0 672 0 8200 0 4100 28 463 1 354 0 666 0 8300 0 4150 28 126 1 359 0 660 0 8400 0 4200 27 800 1 364 0 654 0 8500 0 4250 27 485 1 369 0 649 0 8600 0 4300 27 181 1 373 0 643 0 8700 0 4350 26 888 1 377 0 638 B 2 BBO Frequency Doubling Table B 1 Frequency Doubling in Type I BBO MOPO FDO SHG Crystal Phase der pM V Fundamental Wavelength matching Angle non linear Walkoff mm cm Wavelength output 8 coefficient 0 8800 0 4400 26 604 1 381 0 633 0 8900 0 4450 26 329 1 385 0 627 0 9000 0 4500 26 064 1 389 0 622 0 9100 0 4550 25 808 1 393 0 617 0 9200 0 4600 25 560 1 396 0 613 0 9300 0 4650 25 320 1 399 0 608 0 9400 0 4700 25 089 1 402 0 603 0 9500 0 4750 24 865 1 405 0 599 0 9600 0 4800 24 648 1 408 0 595 0 9700 0 4850 24 439 1 411 0 590 0 9800 0 4900 24 236 1 414 0 586 0 9900 0 4950 24 040 1 416 0 582 1 0000 0 5000 23 851 1 4
29. 670 335 250 13000 19350 680 340 150 13200 19300 690 345 50 13600 19350 700 350 0 14800 19600 710 355 0 15255 19750 720 360 0 14750 19400 730 365 0 15200 19550 740 370 0 15900 19800 750 375 0 16300 19900 760 380 0 16650 20050 770 385 0 17000 20200 780 390 0 17350 20300 790 395 0 17650 20400 800 400 0 18000 20450 810 405 0 18300 20550 820 410 0 18600 20650 830 415 0 18850 20750 840 420 0 19150 20800 850 425 0 19400 20900 C 2 Wavelengths vs Nominal Device Set Point Table C 1 Wavelength vs Nominal Device Set Point MOPO un oe hin 36 Crystal 56 Crystal PB Prism 860 430 0 19650 20900 870 435 0 19900 20950 880 440 0 20200 21050 890 445 0 20650 21150 900 450 0 20900 21200 MOPO FDO 970 C 4 Appendix D Scope Overview Using the Optional RS 232 IEEE 488 Interface This appendix explains how to operate the MOPO FDO system from a remote source using either the optional RS 232 serial interface or the IEEE 488 parallel interface the latter commonly referred to as the General Pur pose Interface Bus or GPIB The parallel interface is much faster than the serial interface but at the control speeds required by the MOPO FDO sys tem either is acceptable Note not all systems have these optional inter faces installed If the computer interface option is included in your system a 25 pin D sub serial connector and a 34 pin Centronics parallel connector will be pr
30. ERTURE SEE MANUAL AVOID EXPOSURE Aperture Label 7 Non interlocked Protective Housing Label 6 S SPECTRA PHYSICS INC 1250 WEST MIDDLEFIELD ROAD MT VIEW CALIFORNIA 94042 MANUFACTURED MONTH YR MODEL S N THIS LASER PRODUCT COMPLIES WITH 21 CFR 1040 AS APPLICABLE MADE IN U S A Certification and Identification Label 1 EF N MOPO FDO Left Side VA om 5 E eb C 98 U Controller Rear Panel DANGER LASER RADIATION WHEN ADJUSTMENT ACCESS Spectra Physics Lasers 1330 TERRA BELL AVENUE MOUNTAIN VIEW CALIF 94039 PLUGS ARE REMOVED AVOID EYE OR SKIN EXPOSURE TO DIRECT OR SCATTERED RADIATION THIS PRODUCT IS MANUFACTURED UNDER ONE OR MORE OF THE FOLLOWING U S A PATENTS 5 033 057 5 047 668 5 053 641 0448 8700 Patent Label 2 Non interlocked Protective Housing Label for Adjustment Access Plugs 4 VISIBLE amp INVISIBLE LASER RADIATION AVOID EYE OR SKIN EXPOSURE TO DIRECT OR SCATTERED RADIATION POWER WAVELENGTH S AND PULSE WIDTH DEPEND ON PUMP OPTIONS AND LASER CON FIGURATION CLASS IV LASER PRODUCT SEE MANUAL Warning Logotype Label 3 Figure 2 3 FDO Radiation Control Drawing Labels and Case Exteriors Laser Safety Sources for Additional Information The following are some sources for additional information on laser safety standards safety e
31. GH POWER LASER RADIATION The Quanta Ray FDO frequency doubler is a high power laser accessory whose beam is a safety and fire hazard Take precau tions to avoid accidental exposure to both direct and reflected beams Diffuse as well as specular beam reflections can cause severe eye or skin damage Precautions For The Safe Operation Of Class IV High Power Lasers e Wear protective eyewear at all times selection depends on the wave length and intensity of the radiation the conditions of use and the visual function required Protective eyewear vendors are listed in the Laser Focus World Lasers and Optronics and Photonics Spectra buyer s guides Consult the ANSI or ACGIH standards listed at the end of this chapter for guidance Keep the protective covers on the laser head and the MOPO FDO at all times e Avoid looking at the output beam even diffuse reflections are hazard ous e Avoid wearing jewelry belt buckles or other objects that may reflect or scatter the beam while using the laser e Do not block 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 Maintain a high ambient light level in the laser operation area so the eye s pupil remains constricted reducing the possibility of damage Post prominent warning signs near the laser operating area Figure 2 1 e Set up experiments so t
32. MOPO FDO 970 Frequency Doubler Option User s Manual S Spectra Physics Spectra Physics Lasers 1335 Terra Bella Road Post Office Box 7013 Mountain View CA 94039 7013 Part Number 0000 244A Rev A January 1996 Preface This manual contains information for safely installing aligning operating maintaining and servicing the FDO 970 optical parametric oscillator fre quency doubler FDO The FDO is designed for use with the Quanta Ray MOPO 710 or 730 optical parametric oscillator and will increase its tunable radiation range to include the region from 440 to approximately 220 nm Although the FDO is an optional MOPO accessory it is housed inside the same enclosure as the MOPO and both devices use the same electronics controller and control menu structure To minimize duplication this man ual is written as a companion to the MOPO manual and primarily covers the operation of the FDO Please refer to your MOPO manual for information specific to that device Your MOPO manual contains a short section on unpacking your unit and inspecting it for damage These brief instructions will allow you to verify your unit arrived in good condition They also explain what to do in the rare event something has been damaged in shipping The introductory chapter describes the FDO system and gives some back ground theory on how it works and it ends with specification tables and outline drawings Following that section is an important chapter o
33. Menu Current FDO Select FDO SERVICE menu diagnostic information OPERATE A SERVICE MOD IDL 0 SETUP WVL 230000 SCAN T 0 CRY 9010 SETUP MONTOR SET 12038 PRS 12034 DEVICE METHOD ADJUST CONT ABORT 56 CRYS Y DISP LT MONITOR V F F gt Fs Fy Fs Select device Select Allows manual Press CONT Cancels the operation type adjustment via to contine current command up down keys SAVE to store the entered data Figure 4 4 The FDO Service Menu The FDO Service menu Figure 4 4 is used to setup test and monitor vari ous system components and to set the type of feedback to be used TRACK or TABLE to drive the system It also provides routines for modifying the database tables associated with the doubling crystals the PB prism and the MOPO crystal Following this section is a section on FDO Table Writing which explains how to create and modify a user defined table for each device Press the OPERATE key to toggle the menu first to the MOPO service menu then to the FDO service menu A third press will take you back to the OPERATE menu The Display The FDO service menu displays these system parameters MOD Mode Displays the system operating mode IDL O Idle the unit is not moving GOTO a goto is in progress SCN a scan is in progress WVL Wavelength Value Displays the current wavelength SET Set Point Command position value for either the crystal CRY or prism PRS This is a relative table value fr
34. OPO FDO 970 Notes 6 Spectra Physics Lasers User s Manual 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 Lasers 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 Spectra Physics Lasers Inc Quanta Ray Products Manager 1330 Terra Bella Avenue Post Office Box 7013 Mountain View CA 94039 7013 U S A Service Centers Benelux Telephone 31 40 265 99 59 France Telephone 33 1 69 18 63 10 Germany and Export Countries Spectra Physics GmbH Guerickeweg 7 D 64291 Darmstadt Telephone 49 06151 708 0 Fax 49 06151 79102 Japan East Spectra Physics KK East Regional Office Daiwa Nakameguro Building 4 6 1 Nakameguro Meguro ku Tokyo 153 Telephone 81 3 3794 5511 Fax 81 3 3794 5510 Japan West Spectra Physics KK West Regional Office Nishi honmachi Solar Building 3 1 43 Nishi honmachi Nishi ku Osaka 550 0005 Telephone 81 6 4390 6770 Fax 81 6 4390 2760 e mail niwamuro O splaser
35. P aulai 0 0 MOPO PUMP M OSC M OSC MONITOR POWER POWER TRK It displays e GCR pump power numerically and graphically master oscillator power numerically and graphically e the error tracking signal of the master oscillator The FDO Monitor Menu page 4 25 is displayed whenever the MONI TOR key is pressed twice OPERATE 0 SETUP MONITOR MODE FDO FDO TRACK POWER DIFF It displays FDO output power numerically and graphically FDO error tracking signal 4 9 MOPO FDO 970 4 10 The Remote Setup Menu page 4 27 is displayed when the MONITOR key is pressed three times OPERATE SETUP SELECT IEEE488 BAUD LOCAL 15 2400 The function keys allow the setting of the remote control source to e LOCAL e RS 232 e EEE 488 and allow the user to set the baud rate for the serial interface and the address for the IEEE 488 parallel interface Operation The Operate Menu Select OPERATE menu Current FDO output Current Signal or Idler output r N OPERATE OPERATE 230 000 a SETUP SU MONITOR 460 000nm GO TO START MOVE RECALL SAVE 0 0 230 000 SCAN MONITOR OCI Fs Fo F3 F4 F5 Na y Go to Begin predeter Manually tune Recall a Save current wavelength mined scan using up down preset program under shown routine keys program number shown Figure 4 2
36. Q SVD and LSQ MRQ are curve fitting routines that are used when writing the user tables The following guidelines are useful for deter mining which curve fitting method to use with a particular device MOPO Crystal Use the LAGRANG method to optimize the table over several 100 nm ranges FDO 56 Crystal Use the LAGRANG method over 25 50 nm ranges then fine tune using one of the LSQ methods in 10 20 nm segments FDO 36 Crystal Same as for the 56 crystal PB Prism Use the LAGRANG method over 25 50 nm ranges then fine tune using the LSG MRQ method in 10 20 nm segments The following describes each of the eight selections available under METHOD MANUAL This selection allows the manual manipulation of the chosen DEVICE via the up down keys when the ADJUST button is pressed DEV SCN Do not use this option This diagnostic technique is used by the factory to align and optimize the performance of the instrument 4 15 MOPO FDO 970 4 16 LSQ MRQ LSQ SVD LAGRNG LIN INT This is a least squares Levenberg Marquardt fitting routine similar to the LSG SVD routine described below and it is prima rily intended for use with the PB prism to improve its pointing stability It differs slightly from the LSG SVD routine in the way it generates the curve points You might have to experiment with this method and the LSG SVD and LAGRANG methods in order to determine the optimum curve fit for your applicati
37. S BCNTS IBCNTL amp CONST EERR CONST TIMO amp H8000 Error detected amp H4000 Timeout DECLARE SU DECLARE SU DECLARE SU DECLARE SU BCLR BYVAL BD3 BFIND BDNAMES BD BRD BYVAL BD RDS BWRT BYVAL BD WRTS UJ UJ UJ UJ DECLARE SUB GpibError Msg DECLARE SUB MopoError Msg CLS PRINT GPIB initialization PRINT D 18 Using the Optional RS 232 IEEE 488 Interface BDNAMES Dev Mopo CALL IBFIND BDNAMES Mopo3 IF Mopo 0 THEN CALL GpibError IBFIND ERROR Clear MOPO GPIB interface CALL IBCLR Mopo3 IF IBSTA AND EERR THEN CALL GpibError IBCLR ERROR CLS DoWaits 0 1 wait 5 seconds between many of the queries multiloopmax 50 TotalLoops 0 START OF MULTILOOP TotalLoop FOR multiloop 1 TO multiloopmax TotalLoops TotalLoops 1 CLS PRINT DOUBLER GPIB COMMUNICATIONS TEST AND DEMO PROGRAM PRINT multiLoop number multiloop of multiloopmax PRINT Total loops TotalLoops PRINT MOPO FDO 970 Expected QUANTA RAY MOPO 710 730 0 V2 05 g Cmd IDN GOSUB WriteMopo GOSUB ReadMopo IF Expe
38. Service Centers 7 12 Australia Spectra Physics Pty Ltd 25 Research Drive Croydon Victoria 3136 Telephone 03 761 5200 Fax 03 761 5600 Benelux Spectra Physics BV Prof Dr Dorgelolaan 20 5613 AM Eindhoven The Netherlands Telephone 40 2 65 99 59 Fax 40 2 43 99 22 France Spectra Physics S A R L Z A de Courtaboeuf Avenue de Scandinavie 91941 Les Ulis Cedex Telephone 01 1 69 18 63 10 Fax 01 1 69 07 60 93 Germany and Export Countries Spectra Physics GmbH Siemensstrasse 20 D 6100 Darmstadt Kranischstein Telephone 06151 7080 Fax 06151 79102 Japan Spectra Physics KK Daiwa Nakameguro Building 4 6 1 Nakameguro Meguro ku Tokyo 153 Telephone 03 3794 5511 Fax 03 3794 5510 All European and Middle Eastern countries in this region not included elsewhere on this list Service and Repair Service Centers cont United Kingdom Spectra Physics Ltd Boundary Way Hemel Hempstead Herts HP2 7SH Telephone 01442 25 81 00 Telex 826411 Fax 01422 68 538 United States and Export Countries Spectra Physics Lasers 1330 Terra Bella Avenue Post Office Box 7013 Mountain View CA 94039 7013 Telephone 1 800 456 2552 Service or 1 800 SPL LASER Sales or 1 800 775 5253 Sales or 1 415 961 2550 Operator Fax 1 415 964 3584 And all countries not included elsewhere on this list 7 13 MOPO FDO 970 7 14 Appendix A Installing a Softwar
39. UP VERIFICATION GOSUB ReadSetup faultflag 0 IF Responsel lt gt ScanBegin THEN faultflag IF Response2 lt gt ScanEnd THEN faultflag 1 IF Response6 lt gt Increment THEN faultflag IF Response4 lt gt Shots THEN faultflag IF Response5 lt gt scans THEN faultflag PRINT PRINT Incremental Scan Setup multiloop PRINT TotalLoops TotalLoops PRINT No PRINT Parameter Sent Received PRINT eesm 4 A 2 5 id PRINT Begin ScanBegin Responsel D 14 u of no f multiloopmax Using the Optional RS 232 IEEE 488 Interface PRINT End ScanEnd Response2 PRINT Increment Increment Response6 PRINT Shots Shots Response4 PRINT Scans scans Response5 PRIN IF faultflag 1 THEN PRINT Incremental Scan Setup ERROR PRINT Program Terminated END END IF PRINT 41 scan PRINT Incremental scan running PRIN type Incr GOSUB WaitForScan PRINT Saving parameter setup TotalLoops total loops PRIN PRINT 1 save 3 Save current operating parameters into non volatile memory as setup record 43 PRINT Recalling parameter setup TotalLoops total loops PRINT PRINT 1 recall 4 Load setup parameters r
40. a wavelength was chosen that is below the MOPO degeneracy band the doubled Sig nal wavelength and is within the operating range of this crystal the section of the table corresponding to 272 345 nm is shifted appropriately For a wave length above the MOPO degeneracy band the dou bled Idler wavelengths the section of the table corresponding to 366 450 nm is shifted 56 CRYS When selected the table values from 219 0 to 271 9 nm are shifted PB PRSM Three table sections are associated with this device The appropriate section will be automatically selected and moved up or down depending on what wavelength the device is at when the adjustments are made Section A 220 0 271 9 nm Section B 272 0 345 0 nm Section C 366 0 450 0 nm DEV RST This routine device reset automatically reverses the selected device 25 counts then slowly brings it forward again to its present position It is useful for minimizing backlash when manually positioning the crystals and the PB prism This func tion is disabled for the MOPO crystal F4 ADJUST allows activation of the appropriate adjustment environment once DEVICE and METHOD are selected Displayed is the current device set point e g CS 9000 the current device position e g CV 9026 and the doubled wavelength e g WL 230000 For devices 56 CRYS 36 CRYS and PB PRSM a nor malized vertical bar graph of the power at the split detector is displayed on the
41. all the connections have been made correctly Do not exceed specified input voltages Follow the instructions in this manual for proper installation and safe oper ation of your laser accessory At all times during installation maintenance or service of your laser accessory avoid unnecessary exposure to laser or collateral radiation that exceeds the accessible emission limits listed in Performance standards for Laser Products United States Code of Federal Regulations 21 CFR 1040 10 d We recommend the use of protective eyewear whenever possible selection depends on the energy and wavelength of the laser beam used as well as operating conditions Consult relevant OSHA ACGIH or ANSI standards for further guidance Any electronic product radiation except laser radiation emitted by a laser product as a result of or necessary for the operation of a laser incorporated in to that product MOPO FDO 970 Focussed Back Reflection Safety Laser optics can be severely damaged even if a small percentage of the out put beam is reflected and focussed back into the laser For instance a com mon simple lens uncoated and positive reflects about 4 of the beam at each surface The first surface reflection back into the laser will diverge but the second surface reflection will focus Intensity at the focus will be very high usually enough to cause optical damage Even surfaces with antireflection coatings may reflect back enough focu
42. and box is the FDO doubled output wavelength The small number below it is the Signal or Idler wavelength that is being doubled The Function Keys F SCANS sets the number of consecutive scans to be performed F BEGIN sets the beginning scan wavelength The FDO beginning wave length can be any number from 220 to 450 nm F4 END sets the end scan wavelength The FDO end wavelength can be any number from 220 to 450 nm F INCR indicates the FDO is set for an incremental scan The increment scan size between dwells is displayed in nanometers below INCR This mode is selected by setting SHOTS to 1 or greater A Setting of O sets the system to continuous scan CONT see below F CONT indicates the FDO is set for a continuous non incremental scan It is selected by setting the SHOTS parameter to 0 A setting of 1 or greater sets the system to incremental scan INCR see above The scan rate is set in nm sec and is limited to a maximum rate dictated by the wave length chosen F SHOTS sets the number of shots that will be issued during an incre mental scan dwell If the number is set to O a continuous scan is selected Operation Running an FDO Scan Select OPERATE Indicates Track Signal or Idler menu or Table mode FDO wavelength wavelength NOPERATE 1230 000 MONITOR 460 000nm GOTO START MOVE RECALL SAVE 230 000 SCAN 0 0 EEE Fe Te MONITOR
43. anges MOPO for master oscillator tracking state Figure 4 9 MOPO Monitor Menu The MOPO Monitor menu Figure 4 9 is accessed by pressing the MONI TOR button It is displayed the first time it is pressed Pressing it a second time displays the FDO Monitor A third press displays the Remote menu A fourth press returns the display to the MOPO Monitor menu The MOPO Monitor Menu provides a visual display of relative GCR pump power MOPO output power and the MOPO tracking difference signal Although the output power displayed is a running average of the last 0 8 seconds of shots it is not an absolute indication of power but a relative ref erence to be used when optimizing output For increased resolution of low signals the gain of the display can be increased up to 16 times The F function key sets the display gain appropriate for the task A higher gain can be helpful for example when calibrating the oscillator at a low power wavelength Lower resolutions are useful in most cases to monitor system output Available gain settings are 1 2 4 8 or 16x and are set using the SSS procedure This feature is saved along with all other data when using the SAVE function from the Operate menu The Display The left most bar graph and digit expresses the GCR pump power in rela tive terms of 0 to 10046 of full power The center bar graph and digit does the same for the master oscillator output power The right most bar graph shows the mas
44. anning in Progress rn 4 21 Figure 4 9 MOPO Monitor Menu 2 eere 4 22 Figure 4 10 FDO Monitor Menu ehh 4 24 Figure 4 11 Remote Menu 2 ee eee ee 4 26 Figure 5 1 FDO Optical Schematic ccc nen 5 3 Figure 5 2 3 D Layout of the FDO 2 2 22 eee eee 5 3 Figure 6 1 Lens Tissue Folded for Cleaning lt 6 3 Figure A 1 Electronics unit showing location of removable PCMCIA memory card ern A 1 Figure D 1 IEEE 488 Dip Switch and Jumper Settings illii D 31 Tables Table 1 1 Crystal Operation Summary 0 2 0 2 0c ees 1 4 Table 1 2 FDO Specifications rne 1 9 Table 4 1 Crystal Operation Summary 0 2 2 2 0000 ren 4 32 Table B 1 Frequency Doubling in Type BBO 2 2 eee B 1 Table C 1 Wavelength vs Nominal Device Set Point s sasaaa nennen nenn C 1 Table D 1 RS 232 C Interface to PC Comm Port D 29 Table D 2 RS 232 C Interface to PC AT Comm Port 22 222 nes seen eee D 30 vii MOPO FDO 970 viii Warnings and Patents 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 Warning Conventions Statement to warn of possible injury or hazard to DANGER personal safety Statement to warn of p
45. ble while scanning Possible Causes Corrective Action FDO is operating below 345 nm and FDO tracking is not enabled From the FDO Monitor menu switch the FDO to TRACK mode FDO is operating above 366 nm and FDO tracking is enabled From the FDO Monitor menu switch the FDO to TABLE mode The prism position table is incor rect Go to the starting point of a scan and optimize the crystal position if necessary using Y DISP then shift the PB prism position to rebalance the FDO DIFF signal using Y DISP Restart the scan Symptom UV power drops when returning to previous wavelength setting s Possible Causes Corrective Action The crystal positioning mechanism is sticky or backlash is present Perform a DEVICE RESET from the FDO Service menu for the active crystal Also try a MANUAL shift followed by an ABORT Then perform a Y DISP to optimize uv output power followed by a SAVE to correct the table If scanning activate the TRACK mode from the FDO Monitor menu to restore uv output power Symptom System does not get to certain wavelengths Possible Causes Corrective Action Target wavelength is out of range The standard FDO software will not allow operation at wave lengths below 220 nm or above 450 nm There is also a degeneracy gap between 345 and 366 nm wavelengths in this range are also inaccessible There are no table values entered for t
46. bscured Verify the FDO DIFF signal on the FDO Service menu is bal anced Verify the uv beam is centered on the output optics and window Symptom Tracking does not work Possible Causes Corrective Action The PB prism is not properly posi tioned Verify uv output and optimize the crystal position if neces sary Then rebalance the FDO DIFF signal using the PB prism Y DISP algorithm The doubling crystals are in the wrong order Verify the 56 crystal is closest to the PB prism and the opti cal axis of each is oriented correctly There is insufficient power to enable tracking Verify the crystal position is optimized for maximum uv out put Pump beam divergence is set incorrectly 710 systems only Adjust the MOPO telescope positive lens to obtain a slightly focusing uv input mode It may also be necessary to reposi tion the power oscillator HR mirror to collimate the MOPO output beam following this adjustment Use appropriate alignment references to maintain correct alignment of the systems Symptom UV power unstable at fixed wavelengths Possible Causes Corrective Action FDO tracking is not optimized From the FDO Monitor menu switch the FDO to TABLE mode and optimize the crystal angle using MANUAL or Y DISP MOPO power is fluctuating Switch the MOPO to TRK TO or TBL TO mode 7 5 MOPO FDO 970 Symptom UV power unsta
47. careful that the tip of the hemostat does not scratch the surface Repeat the operation with a clean tissue on the second surface if any Note a clean surface scatters little or no laser light 4 If the optic was removed install the optic back into its holder or mount and adjust its controls 1f any vertically and horizontally for maxi mum optical output power This concludes the maintenance procedures MOPO FDO 970 Chapter 7 Service and Repair 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 Lasers please call your local service representative A list of world wide service sites is included at the end of this chapter Important for proper operation the FDO is critically dependent on the per formance of the GCR MOPO system These systems provide important sig nals and laser input to the FDO Before performing any corrective adjust ments to the FDO always verify proper operation of the GCR MOPO first A simple re optimization of the MOPO input may be all that is needed to restore the FDO to normal operation The troubleshooting suggestions that follow except for those that refer to the controller electronics and software all assume that the GCR MOPO sys tem has been checked out
48. ce begin GOSUB WriteMopo GOSUB ReadMopo Responsel VAL Response Cmd source end GOSUB WriteMopo GOSUB ReadMopo Response2 VAL Responses D 25 MOPO FDO 970 Cmd source rate GOSUB WriteMopo GOSUB ReadMopo Response3 VAL Response Cmd source shots GOSUB WriteMopo GOSUB ReadMopo Response4 VAL Responses Cmd source scans GOSUB WriteMopo GOSUB ReadMopo Response5 VAL Responses Cmd source incr GOSUB WriteMopo GOSUB ReadMopo Response6 VAL Responses RETURN Inputs Cmd Outputs None WriteMopo CALL IBWRT Mopo Cmd IF IBSTA AND EERR THEN CALL Gpib RETURN Error BWRT ERROR Inputs None Outputs Response ReadMopo Response SPACES 40 CALL IBRD Mopo Response IF IBSTA AND EERR THEN CALL Gpib RETURN D 26 Error BRD ERROR Using the Optional RS 232 IEEE 488 Interface WaitForScan Count 0 WHILE Count scans Wait for last scan to start IF DoWaits THEN GOSUB WaitFiveSeconds Cmd read count GOSUB WriteMopo GOSUB ReadMopo Count VAL Response Cmd read wlen GOSUB WriteMopo GOSUB ReadMopo Wl VAL Response
49. cted lt gt MID Response 1 31 THEN PRINT GPIB communications error PRINT Response expected Expected ELSE PRINT GPIB okay END IF PRINT Response received Response PRINT REM GOTO ContinScanSetup GotoWL 450 multiloop Cmd source goto STRS GotoWL GOSUB WriteMopo Cmd exegoto GOSUB WriteMopo PRINT GOTO running PRINT PRINT Going to GotoWL PRINT Wavelength 0 STB anything other than zero REM WHILE Wavelength lt gt GotoWL old style Wait for GOTO to finish WHILE STB lt gt 0 wait for GOTO to finish Cmd read wlen GOSUB WriteMopo D 20 Using the Optional RS 232 IEEE 488 Interface GOSUB ReadMopo Wavelength VAL Responses Cmd stb read SCPI status byte GOSUB WriteMopo GOSUB ReadMopo STB VAL Response PRINT TotalLoops multiloop multiloopmax Wavelength Wavelength PRINT STB STB IF DoWaits THEN GOSUB WaitFiveSeconds WI E ND ContinScanSetup REM GOTO IncrScanSetup PRINT PRINT Setting up continuous scan PRINT TotalLoops TotalLoops MultiLoop multiloop PRINT ScanBegin 365 multiloop Start at 365 000 nm ScanEnd 367 multiloop Stop at 367 000 nm Rate 1 100 picometers second Shots 0 Continuous scan
50. d the Select Device Clear bus command Refer to the instruction manual for your computer s GPIB interface card for specific details on how to execute a Select Device Clear command 2 Next whether the GPIB or RS232 interface is used send a null string to the MOPO FDO Written in the BASIC programming language this statement would look like PRINT 1 After the interface is initialized the MOPO FDO interface hardware and data input buffer are reset Proceed with the communications link verifica tion test Verification Test The communications link between your computer and the MOPO FDO con troller is easily and quickly tested Simply send the query message to request the MOPO FDO to send back a device identification message 1 Send this query message to the MOPO FDO IDN 2 Receive this device identification message back from the MOPO FDO QUANTA RAY MOPO FDO 710 730 0 V2 05D g NOTE Refer to the Command and Query Messages section later in this appendix for more information about the IDN message The communications link is fully functional when the device identification message is received from the MOPO FDO The system is now ready to receive commands for operation MOPO FDO 970 MOPO FDO Firmware Revision In the MOPO FDO ID message shown above the last piece of data specifies the revision level of the MOPO FDO system firmware The ID message should indicate that the MOPO FDO system firmware is Version 2 05D C
51. e Upgrade From time to time new releases of the MOPO FDO software might be issued that will upgrade your system to add new capabilities or increase its perfor mance The following procedure takes you through the steps required to install the software It is simple and straight forward but it must be fol lowed precisely to prevent any loss of any data tables already stored in your unit 1 Verify the MOPO FDO electronics controller is off 2 Remove the cover from the controller 3 Remove the PCMCIA card that is plugged vertically into the mother board just behind the front panel see Figure A 1 Memory Card Front Panel ve MER 104vVO21 CISEAIA gr gyv Viva gt sxZLG is IHSIBNSLIN o oat wo e TT r 4 51225 SG ha k E la haa y a Figure A 1 Electronics unit showing location of removable PCMCIA memory card 4 Carefully insert the new PCMCIA card making sure the rectangular notch at the base of the card is to the right as viewed from the front of the controller 5 Turn on the controller A 1 MOPO FDO 970 10 11 12 13 14 15 16 Once the opening menu is displayed access the MOPO service screen by pressing the OPERATE button The MENU displayed should be 710 INT This is normal Highlight the CALIB button Leaving the system on replace the new PCMCIA card in with the orig inal card again being careful to note its orientation Use the up down buttons to scroll
52. ecord 44 from non volatile memory GOSUB WaitFiveSeconds are interrupts dead during read routinely hangs w o this wait NEXT multiloop GOTO TotalLoop makes an infinite loop program D 15 MOPO FDO 970 END End of Sample Program ReadSetup PRINT Verifying setup PRINT PRINT 41 source begin GOSUB readdata Responsel VAL response PRINT 1 source end GOSUB readdata Response2 VAL response PRINT 1 source rate GOSUB readdata Response3 VAL response PRINT 1 source shots GOSUB readdata Response4 VAL response PRINT 41 source scans GOSUB readdata Response5 VAL responses PRINT 1 source incr GOSUB readdata Response6 VAL response RETURN rj ke ct n 2 o D 16 Using the Optional RS 232 IEEE 488 Interface Outputs Response readdata Chars Newchar WHILE NewChar lt gt CHRS 10 response Chars WHILE EOF 1 WEND NewChar INPUTS 1 Chars Chars NewChar WEND RETURN WA WaitForScan count 0 WH1 WEND IF PR INT 1 DoWaits THEN GOSU LE count lt gt scans Loop until LF is received Save all but the LF char Wait for next char 1 Input next char Combine all chars Wait for
53. ected for optimum second harmonic conversion efficiency in the FDO BBO Phase matching Angle degrees 10 20 30 40 50 60 70 80 90 200 250 300 350 400 450 500 FDO Output Wavelength um Figure 1 2 Type I BBO Crystal Phase matching Angle vs FDO UV Output Wavelength Introduction Figure 1 3 and Figure 1 4 show the components of the FDO and their rela tive positions as well as the beam path 1 3 PBP TP2 Out Residual Signal and Idler Beams Hit Beam Blocks XTL2 56 XTL4 36 signal idler In Figure 1 3 FDO Optical Schematic Figure 1 4 3 D Layout FDO MOPO FDO 970 1 4 A turning prism intercepts the MOPO Signal Idler beam prior to the two signals being separated and routes it into the frequency doubler If the fre quency doubled range is not to be used turning prism TP is simply removed and placed in the parking area Figure 1 4 and the Signal Idler beams continue on their original path for separation When in place for FDO use TP turns the MOPO Signal Idler output beam 90 and routes it through a long focal length lens DL DL diverges the beam slightly to increase the optical signal to the crystal tracking system The lens is optional and is not required on the MOPO 710 FDO system to obtain a tracking signal Refer to the FDO electronics section later in this chapter for more information on tracking Next
54. election as the default Turn down the LAMP ENERGY control s on the GCR controller Install the FDO TP turning prism in its normal non parked position The prism is fastened to the mounting plate by two 10 32 lock down Screws CAUTION Be careful Hold the prism by the edges of its back plate Bring up the LAMP ENERGY control s to full power Once the MOPO is operating check FDO uv output power If uv output is at full power the FDO is ready to operate If uv power is low try increasing it by slightly adjusting TP The verti cal axis is most sensitive the lower right control knob This completes the conversion from MOPO to FDO output operation Switching from FDO to MOPO Operation 4 30 1 2 Turn down the LAMP ENERGY control s on the GCR controller Move the FDO TP turning prism from its normal position to its parked position near the crystal and PB prism turntables Press the OPERATE button to select the MOPO Service menu Press F to select the mode key Use the up down keys to select your MOPO model and repetition rate without the D for the FDO option Example a Model 730 operating at 10 Hz without the FDO option or when it is not used is designated as 730 10 Hold in the F key until it beeps to activate this selection as the default Bring up the LAMP ENERGY control s to full power This completes the conversion from FDO to MOPO output operation LLL Operation Preparing the Sys
55. elengths Prior to per forming a scan several parameters must be programmed into the controller using the SCAN SETUP function see The Scan Menu later in this chap 4 11 MOPO FDO 970 4 12 ter A scan is not allowed through the degeneracy range between 345 and 366 nm F4 MOVE allows you to tune the output wavelength manually using the up down buttons Simply select MOVE then press the up or down key to move the system to the wavelength wanted The wavelength shown on the display is continuously updated as the system is tuned Note a MOVE is not allowed through the degeneracy range Also as you tune if the system needs to change from Signal to Idler input for the output requested or vice versa or the FDO needs to change the active crystal there will be a pause while the proper crystal rotates into place F RECALL recalls previously saved parameters including the scan rou tine and the GOTO wavelength setting Press the RECALL button then use the up down keys to select the set of stored parameters numbered 0 19 you wish to use Once chosen hold the RECALL button in until it beeps to initiate the recall F SAVE saves the SCAN settings and the GOTO wavelength setting Press the SAVE button then use the up down keys to select the set number 0 19 under which you wish to store the present parameters Once chosen hold the SAVE button in until it beeps to initiate the save Operation The MOPO Serv
56. esent in the upper right hand corner of the rear panel of the MOPO FDO controller This appendix describes how to install set up and use these interfaces Chapter 4 Operation Remote Menu contains information on how to select either of these interfaces for remote control and how to return con trol to the controller front panel It also explains how to set the address for the IEEE 488 interface and the BAUD rate for the RS 232 serial interface Two modes of control are available LOCAL or REMOTE In LOCAL mode the keys and the display on the MOPO FDO controller front panel are used to enter parameters initiate operations and monitor system status In REMOTE mode a terminal or computer is used to perform the same opera tions In addition to the terminal or computer an interface cable is required to connect the command source to the MOPO FDO controller Command messages are strings of ASCII characters the computer or termi nal can send to the MOPO FDO controller where they are interpreted and implemented These messages are organized into two categories com mands and queries Commands direct the MOPO FDO to store a setup parameter or execute an operation whereas queries interrogate the MOPO FDO for a stored parameter value or for an operating status Using these predefined command messages a terminal can provide man ual interactive control of the system via the serial connection Messages are sent from the terminal keyboard a
57. etup PRINT Setting up incremental scan PRIN ScanBegin ScanEnd 240 Increment 2 Shots 100 scans 3 Cmd source 220 multiloop GOSUB WriteMopo Cmd source GOSUB WriteMopo Cmd source GOSUB WriteMopo Cmd source GOSUB WriteMopo Cmd source GOSUB WriteMopo EMENTAL SCAN SETUP VERIFICAT GOSUB ReadSetup faultflag IF Responsel lt gt IF Response2 IF Response6 IF Response4 IF Response5 PRINT 0 multiloop begin STRS Scan end STR ScanEn incr shots scans ScanBegin THEN faul STR Incre STRS Shot STRS scan 2 nanometer steps 100 shots at each WL Make three passes Begin d ment s s ON tflag ScanEnd THEN fault Shots Scans n n flag 1 Increment THEN fau ltflag THEN faultfl ag THEN faultfl ag D 23 MOPO FDO 970 PRINT Incremental Scan Setup multiloop of multiloopmax PRINT TotalLoops TotalLoops PRINT u PRINT Parameter Sent Received PRINT 5 5 55235557 PRINT Begin ScanBegin Responsel PRINT End ScanEnd Response2
58. he desired wavelength Rewrite the Lagrangian table for crystal s and or prism as necessary to cover the new wavelengths Service and Repair Symptom Controller crashes during software update Possible Causes Corrective Action Wrong software revision Verify the software being installed is numbered 2 05D f or later If this is not the case contact Spectra Physics Lasers for updated software earlier Symptom Controller crashes during calibration procedure Software revisions 2 05D e and Possible Causes Corrective Action A function key s was pressed dur ing the procedure while not in the Service menu For example if while modifying the PB prism table using the LAGRNG method an excursion was made to the Monitor menu and a button such as TRACK was pressed the calibra tion procedure would no longer be true and should be aborted If the procedure was continued through to the SAVE command a crash occurs Reboot and restart the procedure Symptom The output beam is misshapen Possible Causes Corrective Action The UV beam is clipped or obstructed Verify the uv beam path is clear and that the beam is properly centered on all optics and apertures There is excessive divergence in the MOPO input beam Readjust the uv pumping optics and or the MOPO power oscillator Contact your Spectra Physics Lasers service repre sentati
59. he laser beam is either above or below eye level 2 1 MOPO FDO 970 2 2 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 VISIBLE amp INVISIBLE LASER RADIATION AVOID EYE OR SKIN EXPOSURE TO DIRECT OR SCATTERED RADIATION POWER WAVELENGTH S AND PULSE WIDTH DEPEND ON PUMP OPTIONS AND LASER CON FIGURATION SEE MANUAL CLASS IV LASER PRODUCT Figure 2 1 Standard Safety Warning sign Figure 2 2 BD 5 High Energy Beam Dump Laser Safety Electrical Safety DANGER HIGH VOLTAGE Voltages present in this unit can cause serious or fatal injury Only qualified personnel should install or perform service proce dures on this equipment Voltage is present on unprotected pins when the unit is opera tional No short circuit protector for motor outputs is provided in the unit The ac input is internally fused When power is applied all parts of the circuit should be consid ered hazardous Allow at least ten minutes for capacitors to discharge Capacitors remain at high voltages for several minutes after the power is removed The above warning label applies to any Spectra Physics Lasers manufac tured FDO pump laser WARNING Do not connect or disconnect the motor or signal cables while ac power is applied Do not apply ac power until
60. hile the unit is still under warranty instead report all problems to Spectra Physics Lasers for warranty repair The FDO 970 includes a firmware upgrade for the MOPO electronic control unit that expands its operational functions to include the FDO This firm ware is installed by the Spectra Physics Lasers service engineer when he sets the system up the first time Once the firmware is installed the user can set the operating parameters for both the MOPO and the FDO from this single system The system can also be run remotely using either the optional RS 232 or IEEE 488 interfaces Lastly we welcome your comments on the content and style of this man ual The last page is a form to aid in bringing any problems you may find to our attention Thank you for purchasing a Spectra Physics Lasers instru ment Table of Contents lir a ERA AAP a a iii Warnings and Patents pO nek kea Ta ded Fo RANA a Da ix cO E AA Xi Chapter 1 Introduction 2c ne aa le 1 1 The MOPO Frequency Doubler Option FDO oocooccccccoco nennen nn 1 1 Adding the FDO to the MOPO system nen 1 1 POW IE WOTIKS A pte Aa da i a ettari par a AN da b esu ro du 1 2 The FDO Crystals nc ER BEC a eee EIS RUE i Ru 1 5 Crystal PB Prism Backlash cece rn 1 6 Beam Splitters s coL A A EE tee eed ote des 1 7 The FDO Electronics ia a aei pe ona nee pA a nennen een 1 7 Chapter 2 Laser Safely 00 000 iara ek annn ala a A aa 2 1 Precautions F
61. ice Menu Current MOPO Select MOPO SERVICE menu diagnostic information 7 OPERATE Bi SERVICE MOD IDL 0 PWR 0 setup WVL 460000 CNT 1202805 SCAN SET 17667 POT 17668 SETUP MONITOR LPT 19113 RPT 12927 MODE CALIB INFO M MIKE RESET 730D30 MODIFY TRK WL MONITOR S Select MODE Shows system information and software revision no Figure 4 3 The MOPO Service Menu Before using your system each time toggle to the MOPO service menu Figure 4 3 by pressing the OPERATE button twice and verify MODE is set correctly to indicate the installed system For example the MODE display box should list your MOPO system type and its rep rate For example if the installed system is a MOPO 730 with a rep rate of 30 Hz and it includes an FDO 730D30 should be displayed A system without an FDO would dis play as 730 30 If the selection displayed is incorrect use the SSS proce dure to correct it If MOPO FDO software updates are required use the Fz button to identify your software revision number This number is also required if and when you talk to your Spectra Physics Lasers service representative regarding service More information on the MOPO service menu is available in the MOPO User s Manual 4 13 MOPO FDO 970 The FDO Service
62. in 1046 of the value it had at installation MOPO FDO 970 12 Use the FDO Monitor menu to verify the FDO output is within 1096 of 13 the value it had at installation If you need to move the DL out of the beam path simply flip it around Loosen the screw on top then remove the entire optic mount and turn it around Place the mount so that the locating pins are reinserted and tighten the screw If the system has just been installed or reinstalled note the values from steps 10 to 12 for future use If you have any problems following a reinstal lation refer to chapter 5 FDO Alignment and your MOPO User s Man ual or call your Spectra Physics Lasers representative Daily Shut Down Procedure 4 4 Follow these steps to shut your system off between periods of frequent use l 2 3 4 5 6 Turn down LAMP ENERGY control s on the GCR to START Press the STOP button Turn the SEEDER switch to STANDBY Turn the key switch on the GCR power supply to the OFF position and remove the key Leave the circuit breaker switch ON so that the HG and injector seeder heaters stay warm This will reduce the warm up period next time Turn off the coolant supply Turn off the MOPO FDO controller This completes the shut down procedure for day to day use In the event the unit is to be moved or left off for a long period of time turn off the cir cuit breaker on the GCR power supply LLL Operation Operating the Contro
63. ing wavelengths When SHOTS is set to 0 CONT is displayed over F to indicate a continuous scan is selected i e there will be no dwell during the scan Just below CONT is the scan rate in nm sec When SHOTS is set to 1 or greater INCR is displayed over F to indicate the system is set for an incremental scan An incremental scan starts at the beginning wavelength and moves the scan by the nm incre ments xxx nm shown under INCR The scan stops dwells at each incre ment and the system delivers the number of shots displayed under SHOTS The scan then progresses and repeats this process until it reaches the scan END wavelength Like the MOPO scan rate the FDO scan rate is nonlinear for a MOPO 710 and 730 This is because the scan rate is dependent on the rotation of the BBO crystal and the beam angle and beam angle vs wavelength is a non linear function The maximum scan rate is lower for scans in the blue end of the spectrum Refer to your MOPO User s Manual for more information Scanning through the degeneracy range is not permitted and a warning to this effect will be displayed The degeneracy range is 345 to 366 nm for the FDO and 690 to 732 nm for the MOPO The SSS procedure is not used with this menu Simply select the function by pressing its button then use the up down keys to set the numerical value inside the associated window 4 19 MOPO FDO 970 4 20 The Display The large number in the upper right h
64. ional RS 232 IEEE 488 Interface Programming Examples The following program statements illustrate the correct format and syntax of MOPO FDO command and query messages These examples are written in Microsoft QuickBasic They do not compose a complete program Refer to the sample program in the next section to see how these program state ments can be used in a complete and executable program OPEN COM1 2400 N 8 1 FOR RANDOM AS 1 PRINT 41 Clear MOPO FDO input buffer PRINT 1 idn MopoID INPUTS 35 1 PRINT MopoIDS Read MOPO FDO ID message PRINT 1 source goto 250 000 PRINT 1 exegoto Set GOTO WL to 250nm Execute GOTO operation ScanBegin 255 ScanEnd 260 Rate 1 Shots 0 Scans 2 PRINT 1 source begin ScanBegin PRINT 1 source end ScanEnd PRINT 1 source rate Rate PRINT 1 source shots Shots PRINT 1 source scans Scans Start at 255 000 nm Stop at 260 000 nm 100 picometers second Continuous scan Make two passes ScanBegin 300 ScanEnd 310 Increment 2 5 Shots 100 Scans 3 PRINT 1 source begin ScanBegin PRINT 1 source end ScanEnd Start at 300 000 nm Stop at 310 000 nm 2 5 nanometer steps 100 shot
65. l Electronics Use the MOPO controller to access FDO table wavelength and service functions If you purchased the FDO unit after the MOPO the Spectra Physics Lasers service engineer that installed the FDO also installed a firm ware upgrade that expanded the control capability of the MOPO electronics unit to include those for the FDO The FDO functions are accessed in the same manner as the MOPO functions Ten buttons are used for operating the MOPO FDO controller Figure 4 1 Three buttons to the left of the display allow selection of the OPERATE SCAN SETUP or MONITOR menus Pressing the OPERATE button brings up the MOPO Service menu and then the FDO Service menu The SCAN SETUP button brings up a menu that allows the user to set the scan parame ters and the MONITOR button toggles between the MOPO and FDO Monitor menus The five buttons on the bottom are soft keys and they select and control various functions depending on which menu is active and which function was previously selected These keys are referred to throughout this manual as function keys 1 through 5 F4 5 Use the two up down arrow keys to the right of the display either to change the numerical value inside the highlighted box on the display or to scroll through the various selections that are offered Menu Buttons Status Display Panel Up Down Buttons
66. last scan to start B WaitFiveSeconds read count GOSUB readdata count PRINT 1 VAL response read wlen GOSUB readdata wl PR PRINT 1 VAL responses INT type TotalLoops multiloop count lt gt 0 DoWaits THEN GOSU v s Wait for last scan to finish B WaitFiveSeconds read count GOSUB readdata count PR INT 1 VAL response read wlen GOSUB readdata wl RETURN VAL responses PRINT type TotalLoops multiloop WEND ua multiloopmax multiloopmax m w v count count MOPO FDO 970 WaitFiveSeconds Timel TIMER Time2 Timel WHILE ABS Timel Time2 lt 5 Time2 TIMER WEND SOUND 1000 3 SOUND 2000 2 RETURN The following is a sample program that tests the optional GPIB IEEE 488 interface Vk oc ck cock ce cce cock ce ck ce ck ce ck ck AK KK ck AK kk ck ck Sk ck ck ck ck ck ck ck ck Ck ck ck Ck ko ck ck ck ko ck Ck ko ko ko ko ko x DOUBGPIB BAS DOUBLER GPIB INTERFACE TEST 02 09 95 Vk oec ck oec ce ck ce ce ck ce cce ce kc ck ck KH KH RK Ck kk ck kk ck ck ck ck ck ck ck ck Ck ck ck Ck ko ck ck ko ko ck Ck ko ko ko kx ko COMMON SHARED NISTATBLK IBSTAS BERR
67. llowed by items that should be done By adhering to this list of procedures you will minimize the possibility of damage to your system and be assured of many hours of error free operation Don ts Do not turn the GCR pump laser from EXTERNAL or LONG PULSE to Q SWITCH mode of operation when the flash lamps are running Diffraction in the beam and or thermal shock to the optics can result in damage e Do not remove a beam block from between the MOPO FDO and the pump laser while the laser is running As in the case above diffraction in the beam and or thermal shock to the optics can result in damage Do not vary the GCR and or MOPO FDO energy with the Q SWITCH DELAY control when the flash lamps are running This can cause a significant energy redistribution in the mode Hot spots can form resulting in damage to system optics Do not adjust the Harmonic Generator HG during the GCR warm up period During this warm up period the temperature in the crystals of the HG is changing Adjusting the HG during this period can result in perfor mance that changes within minutes and requires further adjustments during the warm up period Stable reliable operation of the HG can only be realized once the system has come to thermal equilibrium nominally 30 minutes e Do not run the system with damaged optics Diffraction from damage spots reduce MOPO and FDO conversion effi ciencies due to phase distortions as well as increase the p
68. m components or for general sales assistance dial 1 800 SPL LASER in the United States or 1 415 961 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 mechanical and electronic parts and assem blies manufactured by Spectra Physics Lasers are unconditionally war ranted to be free of defects in workmanship and materials for a period of two years following delivery of the equipment to the F O B point All opti cal elements including the BBO crystal are unconditionally warranted to be free of defects in workmanship and materials for a period of 90 days fol lowing delivery Liability under this warranty is limited to repairing replacing or giving credit for the purchase price of any equipment that proves defective during the warranty period provided prior authorization for such return has been given by an authorized representative of Spectra Physics Lasers In war ranty repaired or replaced equipment is warranted only for the remaining unexpired portion of the original warranty period applicable to the repaired or replaced equipment This warranty does not apply to any instrument or component not manufac tured by Spectra Physics Lasers When products manufactured by others Service and Repair are included in Spectra Physics Lasers equipment
69. mine the optimum curve fit for your application This Lagrange curve fitting method requires that proper SETUP parameters be set as in the previous method see above The algorithm cycles through 7 points within a range specified by the operator and computes a higher order polynomial fitted curve to those points At the end the operator is prompted to save the new values This method is very effective for large wavelength ranges It is intended to get the instrument close enough in calibration for the tracking system to take over This linear interpolation method requires that appropriate wave lengths be set for a wavelength scan in the SETUP menu This means 1 the beginning scan wavelength has to be less than the ending wavelength and ii the wavelengths must be appropri ate for the selected device LLL Operation This algorithm moves the FDO to the start wavelength allows the operator to adjust the selected device moves to the end wavelength again allows adjustment then recomputes the curve between the points and stores the new values if the SAVE function is invoked This is an effective method for quickly optimizing small wavelength regions Y DISP This Y displacement routine uses the ADJUST function key and the up down keys to shift up or down the data table section asso ciated with the selected device and wavelength It sets the FDO to the nearest wavelength for which there is a table value 36 CRYS When selected and
70. mmended to annually check the safety features of the pump laser as well as the MOPO FDO to ensure safety is maintained see Laser Safety section for details Cleaning Laser Optics Losses due to unclean optics which might be negligible in ordinary optical systems can disable a laser and severely reduce the effectiveness of a fre quency doubler Dust on mirror surfaces can reduce output power or cause total failure due to damage Cleanliness is essential and the maintenance techniques used with laser optics must be applied with extreme care and attention to detail Clean is a relative description nothing is ever perfectly clean and no cleaning operation ever completely removes contaminants Cleaning is a process of reducing objectionable materials to acceptable levels Since cleaning simply dilutes contamination to the limit set by solvent impurities solvents must be as pure as possible Use spectroscopic elec tronic or reagent grade solvents and leave as little solvent on the surface as possible As any solvent evaporates it leaves impurities behind in propor tion to its volume Avoid rewiping a surface with the same swab a used swab and solvents will redistribute contamination they will not remove it Both methanol and acetone collect moisture during prolonged exposure to air Avoid storage in bottles where a large volume of air is trapped above the solvent instead store solvents in squeeze bottles from which trapped air can
71. more precise control The bi cell detects a 176 sample of the doubled output beam As the crystal is tuned through the optimum phase matching angle the beam energy shifts from one side of the detector to the other During closed loop track ing the crystal angle command voltage is modified in order to keep the energies on the two sides of the detector balanced The bi cell is a pyroelectric detector with a fairly uniform sensitivity over the wide wavelength range available from the FDO It operates into a charge amplifier that has a resistive reset The measured pulse energy is proportional to the peak of the pulse which is sampled and held by the doubler control board Sample time is synchronized to the laser pulse via a Q switch sync signal A shift in the energy position as the crystal is tuned comes from different processes depending upon whether the unit is a broad band Model 710 OPO or a narrow band Model 730 MOPO The output beam in a Model 710 has frequency content color which is a function of angle because the fre quency was determined by the phase matching angle for the BBO OPO crystal 1 e it has a spatial frequency chirp Doubled output energy shifts because the doubling crystal picks out different colors to phase match at different angles The spatial color chirp in a Model 730 narrow band MOPO is signifi cantly reduced because the operating bandwidth is limited by the grating in the master oscillator To get an energy
72. n the safe use of laser prod ucts The FDO emits radiation that can permanently damage eyes and skin ignite fires and vaporize substances Moreover focussed back reflections of even a small percentage of its output energy can destroy expensive inter nal optics To minimize the risk of expensive repairs injury or even death carefully follow the instructions contained in this chapter In the event the FDO was purchased after the MOPO Chapter 3 lists the conditions and equipment that will be required in order to properly install it when the Spectra Physics Lasers service engineer arrives for the initial set up Although this manual contains a short alignment procedure in chapter 6 wait for the Spectra Physics Lasers service engineer who has been assigned this task under your service agreement to install the unit and set up the system the first time Thereafter allow only personnel trained and authorized by Spectra Physics Lasers to service and set up your laser sys tem The maintenance section contains procedures you must perform from time to time in order to keep your system clean and operational on a day to day basis The service and repair section on the other hand is intended to help guide you or your service representative to the source of any minor prob MOPO FDO 970 lems It contains a replacement parts list and troubleshooting guide as well as a list of Spectra Physics Lasers service centers Do not attempt repairs yourself w
73. nd status responses are returned to the video monitor A computer can also provide automatic control in addition to interactive control and it can use either interface For automatic control MOPO FDO 970 a program designed by the user and based on the command messages can be run on the computer to step the controller through a sequence of opera tions The following tables contain a complete list of commands and queries that provide full control of the MOPO FDO system through either interface Setup Commands Setup Queries SOURCE BEGIN SOURCE BEGIN SOURCE END SOURCE END SOURCE GOTO SOURCE GOTO SOURCE INCR SOURCE INCR SOURCE RATE SOURCE RATE SOURCE SCANS SOURCE SCANS SOURCE SHOTS SOURCE SHOTS Operate Commands Operate Queries ABORT READ COUNT EXEGOTO READ POWER RECALL READ WLEN SAVE SCAN IDN STB Using the Optional RS 232 IEEE 488 Interface Installation RS 232 C Interface IEEE 488 Interface The RS 232 C interface of the MOPO FDO is configured as data communi cations equipment DCE Table D 1 and Table D 2 at the end of this appendix describe the interface connectors and cabling The serial communications port of a typical computer is configured as data terminal equipment DTE A standard 9 wire RS 232 cable is required to connect a computer
74. ne of two preset table values The first table is a factory set read only table that is 4 25 MOPO FDO 970 4 26 based on calculated data It is valid for all FDO systems The second table is a read write table that can be filled with values entered by the user based on actual measured values for his system for increased accuracy The sys tem automatically selects the user defined table when it exists otherwise it uses the factory set table FDO Table Writing later in this chapter explains how to create modify and erase a user defined table The Display The number between the bar graphs indicates output power as a numerical percentage whereas the bar graph to the left of it shows the same thing graphically In some cases the numbers are easier to observe Both dis plays are relative indicators Note setting the screen resolution gain effects both displays i e both the height of the bar graph and the displayed percentage are altered by the gain setting The error correction tracking signal FDO DIFF is shown in the bar graph on the right Because the tracking process requires that the optimum power and mode distribution for a given wavelength be achieved by a balanced output the split cell detector difference signal is used to accurately posi tion the PB prism during calibration The Function Keys F MODE sets TRACK or TABLE monitoring using the SSS process Fo N A F4 N A F FDO POWER display
75. o indicate the angle of rotation for each device and can be used as a reference to verify general alignment Table 1 1 Crystal Operation Summary Wavelength Active Crystal Crystal Set Point Prism Set Point Range nm Device Range Typ Range typ 220 271 9 56 1000 to 22000 10480 to 16000 272 0 345 36 1000 to 12000 15880 to 19360 345 1 365 9 None 366 0 450 36 12000 to 22000 19460 to 21060 The FDO Crystals 70 65 60 55 o O S 50 o D c XI 45 o E c gt 40 Er Q m 35 30 25 20 440 450 460 Introduction FDO Doubled Wavelengths 40 425 415 407 400 390 385 377 370 365 56 Crystal 36 Crystal UM A A O o na E Uc ME VEU D A 470 480 e e o e e o Q Q o o e o o o e o o o o o e o o N e r LO o eo O o T N e r LO CO eo o r LO LO LO LO LO LO LO LO LO LO Ce o o o Ce o Ce o o o Signal Wavelength nm o o o Q0 O O O Q O O co LO o gt o co N LO r e ceo oo co 00 N N N N MOPO Wavelengths Idier Wavelength nm Figure 1 5 The BBO doubling tuning angle for the MOPO FDO Signal Idler and mixed fre quency wavelengths The FDO incorporates a patented design that allows the operator to select any output wavelength from 220 to 440 nm without changing crystals To do this two crystals are used one cut at 36 the other at 56 each covering a part of the to
76. om 1 to 32 760 that is associated with the wavelength requested WVL CRY Crystals Actual position value from the crystal feedback unit it should match the corresponding SET value 4 14 LLL Operation PRS PB Prism Actual position value from the crystal feedback unit it should match the corresponding SET value The Function Keys F DEVICE allows the operator to use the SSS procedure to select the device to be investigated or operated Available devices are 56 CRYS 36 CRYS PB PRSM and OPO CRYS Each is described below 36 CRYS The 36 BBO crystal generates doubled Signal wavelengths below the MOPO degeneracy band from 272 to 345 nm and dou bled Idler wavelengths above the degeneracy band from 366 to 450 nm 56 CRYS The 56 BBO crystal is generates doubled Signal wavelengths from 219 to 271 9 nm PB PRSM The PB prism is responsible for separating the selected doubled frequency from the fundamental frequency and directing the former toward the exit prism OPO CRY is the MOPO BBO crystal responsible for generating the Signal and Idler wavelengths from the GCR pump source F METHOD allows the operator to choose one of eight methods for oper ating the DEVICE selected Use the SSS procedure to choose MANUAL DEV SCN LSQ MRQ LSQ_SVD LAGRNG LIN INT Y DISP or DEV RST Each is described below Once selected the highlight box appears around the ADJUST button refer to the description of F LAGRNG LS
77. on This is a least squares singular value decomposition fitting routine that is primarily intended for use with the PB prism to improve its pointing stability It is similar to the LAGRNG rou tine below but it differs in three ways It cycles through 10 points instead of 7 it has better noise immunity and it takes much less time to compute This method uses a quadratic fit to produce the curve and at the end of the procedure the quality of fit parameters are displayed These parameters are the fitting coefficients ap aj a2 and the merit function of the chi squared distribution the computed points on the curve The merit function is the most important Function values on the order of 5 or less indicate reasonable performance 1 or less excellent performance Numbers higher than 50 may indicate the need to repeat the process with a dif ferent generally smaller wavelength range Use the following general rules to determine the best wavelength range for selec tion For FDO devices where the table density is 10 values per nanometer a 20 nm wavelength range works very well Exceptions are when the 56 crystal is used below 250 nm In this case use 10 nm ranges The MOPO crystal needs a smaller range at shorter wave lengths Since the MOPO table has 1 value per nm wave length ranges of 20 to 30 nm generally work well You might have to experiment with this method and the LSQ MRQ and LAGRANG methods in order to deter
78. on can be entered This procedure assumes the table addressed covers the 375 to 440 nm range of the 36 crystal see Table 4 1 and that a MOPO Model 730D10 laser will be used as the pump source Note that if either of the up down buttons is held down for more than 100 counts during a table writing procedure the count mode becomes acceler ated by up to 20x To resume or to maintain the normal count speed release the key momentarily from time to time An example of writing a table Press the SETUP mode key 2 Press the BEGIN function key to enter the starting wavelength Use the up down keys and BEGIN to input the correct starting wave length in this case 375 nm 3 Press the END function key to enter the ending wavelength in this case 440 nm 4 33 MOPO FDO 970 4 34 10 11 12 Enter the ending wavelength in the same manner as the beginning wavelength Press the OPERATE mode key twice to access the MOPO Service menu Ensure that MODE is set to the proper laser configuration in this case 730D10 Press OPERATE again This brings up the FDO Service Menu Press DEVICE and use the up down keys to select 36 CRYS then hold the DEVICE button in until it beeps If the device selection is not permitted the screen will tell you Press METHOD and use the up down keys to toggle to LAGRNG then hold the LAGRNG button down until it beeps The ADJUST function key is automatically selected Press ADJUST once Use a p
79. ons are valid only when the GCR and MOPO FDO units are mounted on the same optical table The MOPO FDO system should not be near any significant air drafts The system should not be placed near air conditioning vents This may result in changing temperature gradients near the system that can affect its performance as well as stir up dust particles that might settle on sensitive optical surfaces Ideal room temperature is 20 C To ensure stable operation on a day to day basis the recommended minimum and maximum room temperature is 15 and 25 C In addi tion the maximum allowable laboratory temperature variation is 2 C over 8 hours Keep the humidity level below 60 inside the MOPO FDO unit The MOPO FDO unit may be purged with suitably filtered dry air or nitrogen to maintain the desired humidity levels Keep dust to a minimum The diffraction of the pump beam off dust on an optic can induce hot spots in the beam as the beam propagates The hot spots in the beam can cause damage in the optics and the BBO crystal Be careful to not place localized heat sources near the MOPO FDO or under the optical table Large power supplies under the table can have a negative affect on the performance of the GCR MOPO FDO system Chapter 4 Operation FDO 970 Dos and Don ts The following do s and don ts should be made part of your standard labora tory procedures for operating the MOPO FDO First there is a list of things not to do fo
80. ook for dents scratches or other damage If you discover any damage immediately file a claim against the carrier and notify your Spectra Physics Lasers representative Keep the shipping containers If you file a claim you will need them to show that shipping caused the damage If you must return the unit for ser vice these special crates provide maximum protection Spectra Physics Lasers will only ship Spectra Physics Lasers equipment in original con tainers you will be charged for replacement containers Because the FDO resides inside the MOPO and uses the same controller there are no new utilities required All power and signals are provided by the MOPO controller Environmental Considerations In order to maintain stable operation of the GCR MOPO FDO system cer tain environmental conditions must be satisfied The following is a list of these conditions The GCR MOPO FDO system must be installed on an optical table to ensure stable long term operation Critically phase matched OPOs are sensitive to changes in angle of 1 100th of a degree This requires suitable vibration isolation such as that provided by an optical table We recommend using a 4 ft by 10 ft optical table for the GCR MOPO FDO system An 8 in thick optical bench or equivalent is required Do not place the table near sources of vibration i e water pumps air conditioning ducts excimer lasers etc 3 1 MOPO FDO 970 3 2 All MOPO FDO specificati
81. or a later revision If the firmware in your MOPO FDO system is an earlier version than Version 2 05D C you need to update your firmware to the latest version in order to use the computer interface If you need an update call our Spectra Physics Lasers service engineer for assis tance Format and Syntax Rules Format All messages sent to the MOPO FDO must be transmitted in ASCII format The MOPO FDO also sends back all response data in ASCII format Syntax The syntax of the messages sent must conform exactly to the syntax of the examples shown in the next section on Command and Query Messages Notice that all messages begin with a colon A colon is also required between key words of the command string Message Termination Use the ASCII Line Feed character to terminate all messages that are sent to the MOPO FDO The MOPO FDO terminates the response messages that it sends to your computer in two ways It sends the ASCII Line Feed character at the end of all messages Also when using the GPIB interface it additionally sends the GPIB END bus message Using the Optional RS 232 IEEE 488 Interface Command and Query Messages Setup Commands Message Parameter being set SOURCE BEGIN HEHEHE HHH Initial wavelength for a scan SOURCE END HHHH HHHH Final wavelength for a scan SOURCE GOTO HHHH HHHH Destination of the goto wave length SOURCE INCR H Step size in
82. or The Safe Operation Of Class IV High Power Lasers 1 2 0 0 0c cect hr 2 1 Electrical Safety cle Een aes ns RD A en erede En da 2 3 Focussed Back Reflection Safety ren 2 4 Maintenance Reguired To Keep This Laser Product In Compliance With Center For Devices And Radiological Health CDRH Regulations o ooooccocococco nenn 2 4 Sources for Additional Information liiiilssseele res 2 7 Laser Safety Standards is ska RR PX K EA AE ERE REE ER E 2 7 Equipment and Training 4042 ER RI ERE pa aa ar a xu be gs 2 7 Chapter 3 Laboratory Preparation and Pre installation 3 1 Unpacking Your FDQO 970 4 v a ee etek adobe oo DIA em vate NEU WE IE 3 1 Required Utilities comia Rec I x SW Rede E LAN PLA YNANG dee pa s 3 1 Environmental Considerations nes 3 1 Chapter 4 Operation acer 4 1 FDO 970 Do s and Don t s cts 4 1 DOWNS ada see AL Ae M decenti ta IS page PAG A baa MAGA Oconee b a a IAE A 4 1 DOS RE EE ep eR ee Se bg eee Ned es Sel 4 2 Daily Start Up Procedure 20 0 ccc eee 4 3 Daily Shut Down Procedure a tees 4 4 Operating the Control Electronics res 4 5 The SSS Select Scroll Set Procedure ooooocooooocoo ees 4 6 Powering Up the SysSteM ooococcccc hern 4 6 The Menu Structure ooooooco hr mers 4 7 MOPO FDO 970 A Bre Description irreal 4 7 The Operate MEN eec Ie bA RR RP RU eR AA rui edes De
83. ore a scan is not permitted that includes these wavelengths There is an overlap from 266 to 280 nm where both crystals can perform the frequency doubling function To simplify operation an arbitrary point at 272 nm is selected as the cross over point Whenever this point is reached during a GOTO or SCAN a pause ensues as the crystals rotate to exchange active inactive roles The GOTO or SCAN function then continues to proceed to its end wavelength If you find the arbitrary 272 nm point inconvenient for your purposes another point within the 266 to 280 nm range may be selected Please call your Spectra Physics Lasers representative for modified software Please note however that you will be required to make the software update change yourself It is a fairly simple procedure however and appendix A contains the information necessary for you to do this Crystal PB Prism Backlash 1 6 It is important to note that there is a small amount of backlash in the drive system To maintain the extreme accuracy of the MOPO FDO this backlash is accounted for by using a simple procedure The MOPO FDO always approaches the end wavelength of a GOTO or SCAN command from a defined direction This direction depends on whether it is the Signal or Idler wavelength that is being doubled When scanning to an end point from the opposite direction there will be a noticeable 0 5 nm overshoot of the final wavelength followed by an immediate direction reversal
84. orrective Action The display gain may be set too high Press FA to change the gain setting Fundamental light is present If working around the 450 nm range the fundamental wave length is also present this is normal At other wavelengths verify the prism is correctly aligned Symptom The FDO DIFF bar graph does not move up and down Possible Causes Corrective Action The prism is not properly aligned Align the prism to direct the pick off beam at the photodetec tor Use the PB prism table adjust Only half of the bi cell is working Verify both sides of the cell work by directing a beam at both sides and noting the signal on the menu If one side is truly dead replace the detector assembly There is not enough beam diver gence for proper detection Adjust the DL lens to increase the divergence Beam width should be about 3 mm The pump beam is not collimated Refer to the GCR and MOPO User s manuals for instructions Service and Repair Symptom Low UV output Possible Causes Corrective Action The FDO crystal is not located properly Access the FDO Service menu and use the MANUAL modifica tion method to determine if the crystal can be tuned to a bet ter location Then perform a Y DISP and note the PB prism tracking signal If it not symmetric adjust it using the appro priate algorithms Output uv beam is clipped or o
85. ossible damage to equip WARNING ment Statement to warn against or to prevent poor per CAUTION formance or error Statement to cover exceptional circumstances or NOTE reference Patents The MOPO FDO products are manufactured under one or more of the fol lowing patents 5 033 057 5 047 668 5 053 641 SI Units The following System International SI units abbreviations and prefixes are used in this Spectra Physics Lasers manual Quantity Unit Abbreviation mass kilogram kg length meter time second S frequency hertz Hz force newton N energy joule J power watt W electric current ampere A electric charge coulomb C electric potential volt V resistance ohm Q inductance henry H magnetic flux weber Wb magnetic flux density tesla T luminous intensity candela cd temperature kelvin K pressure pascal Pa capacitance farad F angle radian rad Prefixes tera 107 T deci 107 d nano 10 n giga 10 G centi 107 c pico 1079 p mega 10 M mill 103 m femto 1075 f kilo 10 k micro 10 u atto 1018 a xi Chapter 1 Introduction The MOPO Frequency Doubler Option FDO Adding the FDO to the MOPO system The FDO 970 is a MOPO option that extends its uv output to include the wavelength range from 440 to 220 nm The FDO platform installs in the output end of the MOPO enclosure Figure 1 1 and can be installed either at the time the MOPO is purchased or added to i
86. otton 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 Use photographic lens tissue to clean optics and windows Use each piece only once dirty tissue merely redistributes contamination it doesn t remove it Maintenance Cleaning Optical Components Equipment Required e Dry nitrogen canned air or rubber squeeze bulb e Photographic lens tissue e Spectroscopic grade methanol and acetone e Forceps e Hemostats Cleaning Prisms Crystals and Mirrors Most optics can be cleaned in place If you do not remove them there is less chance of misalignment However be careful you do not allow excess solvent to wick or run down the surface It is very possible the solvent can attack the adhesive holding the optic to the mount or base and either loosen it or worse contaminate the optical surface with adhesive material A high energy pulse can then burn the material into the surface and permanently damage the optic 1 Blow away dust particles or lint using nitrogen or air 2 Folda piece of lens tissue into a pad about 1 cm on a side and clamp it in a hemostat Figure 6 1 Saturate the pad with methanol shake off the excess resaturate and shake again No not use excessive solvent Figure 6 1 Lens Tissue Folded for Cleaning 3 Wipe one surface bottom to top in a single motion Be
87. ower meter or the on screen display and the up down keys to adjust the crystal for maximum output power at the specified wave length Always approach optimum power from the lower wavelength to avoid errors introduced by backlash Press the CONTinue function key until it beeps Repeat steps 9 through 11 until all the wavelengths have been recorded for the crystal position portion of this procedure After seven points have been entered SAVE will appear Press and hold this button in until it beeps to save the data or it will be lost It takes about 30 sec onds for the computation to complete and the highlight box around SAVE to disappear This completes the writing of a new user defined table section for the 36 crystal over the wavelength range selected in steps 2 and 3 above Table 4 1 Crystal Operation Summary Wavelength Active Crystal Crystal Set Point Prism Set Point Range nm Device Range Typ Range typ 220 271 9 56 1000 to 22000 10480 to 16000 272 0 345 36 1000 to 12000 15880 to 19360 345 1 365 9 None 366 0 450 36 12000 to 22000 19460 to 21060 Chapter 5 FDO Alignment Quick Start Procedure Refer to your MOPO manual for instructions on how to quickly align the MOPO FDO to the GCR pump laser This procedure is meant for use by field service engineers or trained personnel to set up the system after it has been relocated not as a first time se
88. parallel interface NK KKK KKK KKK KK KKK ce KK ke ce kk ck AK KK KH C kk ck ck Sk ck Ck ck ck ck ck ck ck Ck ko ck Ck ko ck ck ko ko Sk Ck ko ko ko ko ko x FDO 700 SERIES SAMPLE PROGRAM LJB 07 28 95 This program tests the RS232 doubler interface Max baud rate is 2400 NKR KK KKK KKK KK KKK KKK KE RK KH ce AK KK KH C kk ck ck ck ck ck ck ck ck ck ck ck Ck ko ck Ck ko ck ck ko ko ck Ck ko ko ko ko ko x CLS DoWaits 0 1 wait 5 seconds between many of the queries multiloopmax 50 OPEN COM2 2400 N 8 1 FOR RANDOM AS 1 TotalLoops 0 TotalLoop FOR multiloop 1 TO multiloopmax TotalLoops TotalLoops 1 CLS PRINT MOPO SERIAL COMMUNICATIONS TEST AND DEMO PROGRAM PRINT multiLoop number multiloop of multiloopmax PRINT Total loops TotalLoops PRINT PRINT 1 Clear MOPO input buffer PRINT 41 idn MopoID INPUTS 35 1 PRINT MopoIDS MOPO FDO 970 GotoWL 448 multiloop go to idler extreme wavlength PRINT 41 source goto GotoWL PRINT 41 exegoto PRINT GOTO running PRINT Wavelength 0 STB anything other than zero REM WHILE Wavelength lt gt GotoWL old style Wait for GOTO to finish WHILE STB lt gt 0 wait for GOTO to finish PRINT read wlen GOSUB readdata
89. plays the Remote menu A fourth press returns the display to the MOPO Monitor menu The FDO Monitor Menu provides a visual display of relative FDO output power and the tracking difference signal Although the output power dis played is a running average of the last 0 8 seconds of shots it is not an absolute indication of power but a relative reference to be used when opti mizing output For increased resolution of low signals the gain of the dis play can be increased up to 16 times The F function key sets the display gain appropriate for the task A higher gain can be helpful for example when calibrating the oscillator at a low power wavelength Lower resolutions are useful in most cases to monitor system output Available gain settings are 1 2 4 8 or 16x and are set using the SSS procedure This feature is saved along with all other data when using the SAVE function from the Operate menu F offers two operating modes TRACK or TABLE Figure 4 10 shows TRACK mode selected which uses the split cell detector to locate the position of the output beam As the beam moves from one side of the cell to the other an error signal is generated that the system uses to continuously adjust the crystal to maintain optimum power and a balanced signal on the split cell detector The relative magnitude and direction of the error signal is dis played by the right hand bar graph If TABLE mode is selected the crystal angle is adjusted based on o
90. quipment and training Laser Safety Standards Safe Use of Lasers Z136 1 American National Standards Institute ANSI 11 West 42nd Street New York NY 10036 Tel 212 642 4900 A Guide for Control of Laser Hazards American Conference of Governmental and Industrial Hygienists ACGIH 1330 Kemper Meadow Drive Cincinnati OH 45240 Tel 513 742 2020 Laser Safety Guide Laser Institute of America 12424 Research Parkway Suite 125 Orlando FL 32826 Tel 407 380 1553 Equipment and Training Laser Focus World Buyer s Guide Laser Focus World Pennwell Publishing 10 Tara Boulevard 5th Floor Nashua NH 03062 Tel 603 891 0123 Lasers and Optronics Buyer s Guide Lasers and Optronics Gordon Publications 301 Gibraltar Drive P O Box 650 Morris Plains NJ 07950 0650 Tel 201 292 5100 Photonic Spectra Photonic Spectra Laurin Publications Berkshire Common P O Box 4949 Pittsfield MA 01202 4949 Tel 413 499 0514 MOPO FDO 970 2 8 Chapter 3 Laboratory Preparation and Pre installation Unpacking Your FDO 970 Required Utilities IMPORTANT The FDO is designed to be installed by a trained Spectra Physics Lasers Service Engineer If you have not already done so please contact the SPL Service Organization to arrange installation Your FDO was carefully packed for shipment if its crate arrives damaged have the shipper s agent present when the unit is unpacked Inspect it as you unpack l
91. r menu verify a uv power is maximized Perform a Y DISP on the FDO crystal from the FDO Service menu if required refer to the FDO Service menu section in this chapter b the FDO difference signal is balanced Perform a Y DISP on the PB crystal from the FDO Service menu if required 4 31 MOPO FDO 970 10 From the FDO Monitor menu press F to select the mode key Use the up down keys to select TRACK Hold in the F key until it beeps to activate TRACK as the default set ting From the Scan Setup menu enter the desired scan parameters From the Operate menu initiate the scan by pressing the F the START SCAN key Operating at Fixed Wavelengths 4 32 If TABLE mode is already selected DT is displayed in the Operate menu skip to step 4 1 Ze 3 From the FDO Monitor menu press F to select the mode key Use the up down keys to select TABLE Hold in the F key until it beeps to activate TABLE as the default set ting From the Operate menu GOTO the desired wavelength If uv power does not appear optimized use MANUAL or Y DISP from the FDO Service menu for the active FDO crystal to optimize uv output power Some improvement in power stability might be achieved by placing the MOPO in TRK TO or TBL TO mode from the MOPO Service menu refer to the MOPO Service menu section in this chapter LLL Operation FDO Table Writing The MOPO FDO system supports two wavelength crystal angle sets of
92. ress by holding in F until it beeps BAUD Rate Selection The default serial BAUD rate is 2400 but it can be changed to 300 or 1200 To change it 1 Press F to indicate the serial address is to be changed 2 Use the up down keys to scroll to the BAUD rate desired 3 Activate the serial interface at the selected BAUD rate by holding in F until it beeps The Display Nothing is displayed in the large window The Function Keys F LOCAL sets system control to either the front panel local or to the IEEE 488 or the RS 232 interface The selection is shown in the display box 4 28 LLL Operation F IEEE 488 sets the address for the IEEE 488 parallel interface shown in the display box See IEEE 488 Address Selection above for information on changing this address F4 BAUD sets the BAUD rate for the RS 232 serial interface shown in the display box See BAUD Rate Selection above for information on chang ing the BAUD rate Fe N A Fs N A 4 29 MOPO FDO 970 Switching Between MOPO and FDO Operation Switching from MOPO to FDO Operation Press the OPERATE button to select the MOPO Service menu Press F to select the mode key Use the up down keys to select your MOPO model and repetition rate and make sure it includes the D for the FDO option Example a Model 730 operating at 10 Hz with the FDO option is des ignated as 730D10 Hold in the F key until it beeps to activate this s
93. robability of further damage to optics down the beam line e Do not use the VARIABLE REP RATE option with the MOPO FDO MOPO FDO 970 At different rep rates the beam will not be collimated which will result in a degradation of FDO performance as well as the possibility of damaging the optics e Do not run the GCR if the Seeder is off or is performing poorly Linewidth performance will degrade and parasitic oscillations may result In addition damage to the broadband dichroics may occur Do not use the GCR SINGLE SHOT option when running the MOPO FDO Increased thermal lensing in the rod may result in damage due to ther mal shock to the optics In addition seeded performance of the GCR is not possible and results in poor linewidth performance Do not lean on the GCR or MOPO FDO units during operation nor place items on them Also do not lean on the optical table The entire MOPO system is very sensitive to small amounts of move ment in the beam Leaning on the optical table the GCR or the MOPO FDO will compromise system performance by inducing beam move ment Do not remove the MOPO FDO cover during operation The cover prevents room drafts from compromising temperature sta bility and also maintains a dust free environment for stable long term operation For reasons of safety it keeps stray beams and reflections confined Dos e Check the optics on a regular basis for dust and damage If dust is present blo
94. s at each WL Make three passes MOPO FDO 970 PRINT 41 source incr Increment PRINT 1 source shots Shots PRINT 1 source scans Scans PRINT 1 source begin GOSUB ReadData PRINT 1 source end GOSUB ReadData PRINT 1 source rate GOSUB ReadData PRINT 1 source shots GOSUB ReadData PRINT 1 source scans GOSUB ReadData PRINT 1 source incr GOSUB ReadData MONITOR OPERATING STATUS PRINT 1 read wlen GOSUB ReadData PRINT 1 read count GOSUB ReadData PRINT 1 read power GOSUB ReadData READ DATA SUBROUTINE Inputs None Outputs Response ReadData Chars NewChar WHILE NewChars lt gt CHRS 10 Response Chars WHILE EOF 1 WEND NewChar INPUTS 1 1 Chars Chars NewChar WEND RETURN D 10 Loop until LF is receiving Save all but the LF char Wait for next char Input next char Combine all chars Using the Optional RS 232 IEEE 488 Interface Sample Programs The following programs are written in the Microsoft QuickBasic program ming language They will run on any IBM PC compatible computer The first program sends messages to the MOPO FDO through the RS 232 C serial communications port the second uses the optional GPIB IEEE 488
95. s co p United Kingdom Telephone 44 1442 258100 United States and Export Countries Spectra Physics 1330 Terra Bella Avenue Mountain View CA 94043 Telephone 800 456 2552 Service or 800 SPL LASER Sales or 800 775 5273 Sales or 650 961 2550 Operator Fax 650 964 3584 e mail service O splasers com sales O splasers com Internet www spectra physics com And all European and Middle Eastern countries not included on this list And all non European or Middle Eastern countries not included on this list Report Form for Problems and Solutions We have provided this form to encourage you to tell us about any difficul ties you have experienced in using your Spectra Physics instrument or its manual problems that did not require a formal call or letter to our service department but that you feel should be remedied We are always interested in improving our products and manuals and we appreciate all suggestions Thank you From Name Company or Institution Department Address Instrument Model Number Serial Number Problem Suggested Solution s Mail To FAX to Spectra Physics Inc Attention SSL Quality Manager SSL Quality Manager 650 961 7101 1330 Terra Bella Avenue M S 15 50 Post Office Box 7013 Mountain View CA 94039 7013 U S A E mail sales O splasers com www spectra physics com
96. screen Figure 4 5 A bar graph of the split detector difference signal is displayed to the right of it The two digit number between the bars shows the percentage of full scale MOPO FDO 970 4 18 Current FDO Relative output Select FDO SERVICE menu diagnostic information power Error signal la LIL SERVICE wr 23 CS TT SCAN SETUP Cv 3026 r SETUP MONITOR DEVICE METHOD ADJUST CONT ABORT 56 CRYS Y DISP mn MONITOR Iv Fs Fy Fs Fa Fs Selected device Selected Allows manual Press CONT Cancels the operation type adjustment via to contine current command up down keys SAVE to store the entered data Figure 4 5 The Adjustment Environment Use the up down keys to change the device set point and posi tion Then watch the display and optimize the power and or bal ance at the split detector If the up down keys are held down for more than 100 counts the count speed increases by up to 20x Release the key from time to time to maintain a slow count speed The OPO CRYS is adjusted in a similar manner The second vertical bar graph represents the tracking signal Tracking is dis abled during adjustment however and the bar graph merely verifies the tracking state and display consistency F CONT SAVE press CONT to continue the process that was selected using the METHOD function key When the
97. shift a small amount of fundamental beam divergence must be present so that the doubling crystal phase match ing condition can pick out a portion of the fan of rays to double Thus the energy will shift as the crystal is tuned through its optimum angle Table 1 2 FDO Specifications Introduction Tuning Range 220 440 nm Details of Tuning 220 272 nm 56 crystal 272 345 nm 36 crystal 366 440 nm 36 crystal Efficiency With MOPO 730 gt 10 250 nm guaranteed gt 10 250 440 nm typical Amplitude Stability 15 Linewidth 0 3 cm Beam Diameter Nominal 6 mm depends on MOPO used Beam Divergence lt 1 mrad Pointing Stability 250 urad Maximum Scan Rate 39 125 nm sec System Repetition Rate 1 hour 1 second average static wavelength FDO MOPO Tuning Curves Signal Energy Doubled Signal Idler 200 300 400 710 10 20 or 30 Hz set at factory Idler 1000 2000 Wavelength nm Outline Drawings Because the FDO is an internal part of the MOPO system the outline dimen sions are the same as that for the MOPO Refer to your MOPO manual MOPO FDO 970 1 10 Chapter 2 Laser Safety The Quanta Ray FDO 970 frequency doubler is an accessory for the MOPO optical parametric oscillator and is designed to extend the MOPO output wavelength range to include the wavelengths from 440 to 220 nm Output from the FDO can be visible or invisible DANGER HI
98. ssed energy to cause damage To avoid this hazard minimize focussed back reflections When they are unavoidable direct them off axis to a harmless position or into a beam dump Damage due to focussed back reflections is not covered by the Spectra Physics Lasers warranty Maintenance Required To Keep This Laser Product In Compliance With Center For Devices And Radio logical 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 The FDO is a passive laser accessory As such it has no inherent interlock devices For verification of CDRH safety compliance including interlocks verify pump laser safety features To maintain compliance ver ify the operation of all features listed in your Nd YAG pump laser manual either annually or whenever the product has been subjected to adverse envi ronmental conditions eg fire flood mechanical shock spilled solvents Warning labels for the FDO are identified on the radiation control drawings below B Laser Safet o Ee Eme o AU A MOPO FDO Right Side PA T20 BOO 50 amp E MOPO FDO Output End VISIBLE AND INVISIBLE LASER RADIATION IS EMITTED FROM THIS AP
99. t at a later date The soft ware that drives the MOPO controller is modified with firmware so that it includes the controls required for selecting FDO wavelengths and other ser vice functions If the FDO was purchased some time after the MOPO was installed the service engineer who originally installed the FDO also installed this firmware upgrade Figure 1 1 The MOPO showing the FDO unit installed 1 1 MOPO FDO 970 How it Works 1 2 To set the MOPO system for a frequency range covered by the FDO simply use the normal MOPO commands to enter the desired output uv wave length The system will automatically set the MOPO BBO crystal angle for the proper fundamental Signal or Idler frequency and then the angle of the FDO crystals and prisms for the selected doubled output wavelength The FDO employs a Type I BBO doubling crystal that produces a second harmonic output frequency when it is tuned to the proper phase matching angle for the MOPO output frequency the FDO input frequency Figure 1 2 shows the BBO crystal phase matching angle as a function of output wavelength The equation below shows how much second harmonic output power P can be expected for a given input power 2 2 2 20 A where d is the effective nonlinear coefficient P is the fundamental input power 1s the crystal length dis a phase matching factor and A is the cross sectional area of the beam in the doubling crystal Both and A have been sel
100. tables The first is a backup read only computer generated theoretical table that is based on the phase matching properties of the BBO crystal The sec ond table set is created by the user to fine tune the system and to set the wavelength parameters based on actual measurements The controller uses the compter generated table only when the default user table is not present 1 e it has been erased The FDO is shipped with an optimized factory generated user table There are six tables in each set 36 crystal 272 345 nm range 366 450 nm range 56 crystal 220 271 9 nm range PB prism 220 271 9 nm range 272 345 nm range 366 450 nm range Each segment of the user table can be modified in whole or in part typi cally in part Refer to the FDO Service Menu section earlier in this chap ter for information on methods that can be used to modify the curve Once a wide section of the crystal angle vs wavelength range curve is close to the ideal a smaller range can be calibrated to best fit the scan range of immediate interest If the factory table values are not precise enough for your application they can be changed The following procedure steps you through a typical table writing sequence There are two parts one for setting the wavelength val ues associated with a particular crystal at a particular angle and one where the procedure is repeated so the same wavelength values associated with prism positi
101. tal wavelength range as indicated by Table 1 1 and Figure 1 5 One of the crystals is rotated 15 with respect to the input beam to set it to the proper phase matching angle for frequency doubling the selected wavelength This becomes the active crystal The second crystal is not set to the phase matching angle and is essentially inactive The incoming light simply passes though it However it is counter rotated to the active one to the same degree of rotation in order to provide compensation for MOPO FDO 970 beam translation and walk off effects created by the active crystal Only one crystal is ever active at a time As shown in Figure 1 5 the 56 crystal doubles the MOPO Signal wave lengths from 440 to 543 nm for an FDO output of 220 to 271 9 nm The 36 crystal doubles the MOPO Signal wavelengths from 544 to 690 nm for an FDO output of 272 0 to 345 nm The 36 crystal also doubles the MOPO Idler wavelengths from 732 to 880 nm for an FDO output of 366 to 450 nm The Mix wavelengths shown in Figure 1 5 represent back conversion of Signal and Idler in the BBO crystal Because the GCR is capable of produc ing output at this wavelength 355 nm and in much greater power than the FDO the MOPO FDO controller is designed to avoid this condition As shown in Table 1 1 neither crystal is active from 345 1 to 365 9 nm This is the MOPO BBO crystal degeneracy range where no output is gener ated between these frequencies Theref
102. te description of these interfaces and their command structure and explains how to use them Several software examples are also provided Caution When activating the selection during the following procedures if the function key is not held in until the beep the unit will revert back to its previous setting when you leave this menu Control Source Selection To select the control source 1 Press F to begin the selection process 2 Use the up down keys to toggle to the desired device RS 232 IEEE 488 or LOCAL 3 Press F and hold it in until it beeps to activate the chosen control source 4 27 MOPO FDO 970 When one of the optional interfaces is selected as the control source LOCAL is displayed over F Pressing F returns the system to local opera tion Figure 4 12 a N OPERATE OPERATE M Sr E 2 0 000 D Returns control back to front panel Figure 4 12 Returning Local Control to the System IEEE 488 Address Selection The default address for the IEEE 488 interface is 15 but it can be changed to any address from 0 to 31 To change it Press F to place the cursor under the digit to be changed 2 Usethe up down keys to scroll the number to the digit desired 3 Repeat this procedure to select the second digit 4 When the new address is selected activate the IEEE 488 at this add
103. te E ae E ep eR MA MEE D 6 SMA P Re A ENTE D 6 Message Termination cogo a RR RR t CHER ee D 6 Command and Query Messages o oocccoco een een D 7 Programming Examples 2 sacara be er EO ai ieee xU i E die D 9 Sample Programs desta wate elas ER e VO eO ar Vis tree Zeiler D 11 Connections S rera de i E deux dade nit EE REM D 29 Figures Figure 1 1 The MOPO showing the FDO unit installed LL ks 1 1 Figure 1 2 Type I BBO Crystal Phase matching Angle vs FDO UV Output Wavelength rr 1 2 Figure 1 3 FDO Optical Schematic en 1 3 Figure 1 4 3 D Layout FDO err 1 3 Figure 1 5 The BBO doubling tuning angle for the MOPO FDO Signal Idler and mixed frequency wavelengths LL 1 5 Figure 1 6 Electronics Interconnect Diagram LL 1 7 Figure 2 1 Standard Safety Warning sign LL aka aka 2 2 Figure 2 2 BD 5 High Energy Beam Dump Ls 2 2 Figure 2 3 FDO Radiation Control Drawing Labels and Case Exteriors 2 5 Figure 2 4 FDO Radiation Control Drawing Case Interior llli eee 2 6 Figure 4 1 Initial configuration of the electronics panel 4 5 Figure 4 2 The Operate Menu 2 222 mr 4 11 Figure 4 3 The MOPO Service Menu oocccccccco hr 4 13 Figure 4 4 The FDO Service Menu coccoccccoc rrr 4 14 Figure 4 5 The Adjustment Environment LL ks 4 17 Figure 4 6 The Scan Setup Menu 0 000 rn 4 18 Figure 4 7 Initiating a Scan rn 4 20 Figure 4 8 Sc
104. tem for Scanning For wavelength scans above 366 nm it is preferable to set the FDO to TABLE mode When set to TABLE mode a DT appears in the lower right portion of the Operate menu For wavelength scans below 345 nm it is generally preferable to have the FDO set to TRACK mode When TRACK mode is selected DL is displayed When scanning outside the FDO wave length region it is preferable to have the FDO operating in TABLE mode TRACK and TABLE are selected via the FDO Monitor menu CAUTION It is essential that the FDO be in TABLE mode while performing any adjustments to the crystal or prism tables Scanning Wavelengths Above 366 nm 1 From the Operate menu GOTO the desired starting wavelength 2 From the FDO Monitor menu press F to select the mode key 3 Use the up down keys to select TABLE 4 Holdin the F key until it beeps to activate TABLE as the default set ting 5 From the Scan Setup menu enter the desired scan parameters 6 From the Operate menu initiate the scan by pressing F the START SCAN key Scanning Wavelengths Below 345 nm 1 From the Operate menu GOTO the desired starting wavelength If TABLE mode is already selected DT is displayed in the Operate menu skip to step 5 2 From the FDO Monitor menu press F to select the mode key 3 Use the up down keys to select TABLE 4 Holdin the F key until it beeps to activate TABLE as the default set ting 5 From the FDO Monito
105. ter oscillator tracking error signal This bar is ideally at the center of the graph i e in its balanced position 4 23 MOPO FDO 970 The Function Keys F MOPO MONITOR display box is a label to indicate the menu displayed the button provides no function F PUMP POWER display box is a label to indicate the bar graph above it the button provides no function Fs N A F4 M OSC POWER display box is a label to indicate the bar graph above it The function key sets the screen gain to 1 2 4 8 or16x using the SSS procedure Fs M OSC TRK changes the MOPO tracking mode see the MOPO User s Manual It also identifies the bar graph displayed above it 4 24 Operation The FDO Monitor Menu Relative FDO Relative Select output Oto 100 FDO Error correction MONITOR menu power output power tracking signal g N OPERATE SETUP P SOAN MONITOR 30 MODE FDO FDO TRACK POWER DIFF MONITOR 7 Fy Fo F3 F4 F Ct E Track or Table Sets the screen gain Labels for operating mode selection to 1 2 4 8 or 16 bar graphs only Figure 4 10 FDO Monitor Menu The FDO Monitor menu Figure 4 10 is accessed by pressing the MONI TOR button The MOPO Monitor menu is displayed the first time it is pressed Pressing it a second time displays the FDO Monitor menu A third press dis
106. terface from O to 31 default is 15 a Press F to place the cursor under the digit to be changed b Use the up down keys to toggle to the digit desired c Move to the second digit 1f necessary and repeat steps a and b d When the address is selected press F until it beeps to activate the address 3 Setthe serial BAUD rate to 300 1200 or 2400 default is 2400 a Press F to select the BAUD rate b Use the up down keys to toggle to the rate desired c Press F3 until it beeps to activate the BAUD rate 4 Select the active interface a Press F momentarily b Use the up down keys to toggle to the interface desired c Press F until it beeps to activate the selected interface The MOPO FDO controller should now be set to either the RS 232 or IEEE 488 remote control modes and command and query messages can now be sent to it from your computer The selected interface will remain active until changed again by you 5 Press F5 LOCAL to return control to the front panel Using the Optional RS 232 IEEE 488 Interface Saving Setup Parameters The RS 232 and IEEE 488 setup parameters will not be saved via remote command Only GOTO and SCAN parameters can be saved via remote com mand Initialization After turning on the MOPO FDO controller and selecting either RS 232 or IEEE 488 control initialize the computer interface as outlined below Procedure to Initialize the Interface 1 Ifthe IEEE 488 interface is used sen
107. that approaches the final wavelength from the correct direction This back lash correction feature produces highly accurate positioning of the FDO crystals and prism Beam Splitters The FDO Electronics FDO Output Beam Introduction Beam splitter BS picks off a small amount of the beam for use as feedback for the crystal prism tracking system The front surface beam reflection is routed to the bi cell detector The reflection off the wedge s second surface is unwanted and is captured by a small beam block The second beam split ter BS is oriented with its wedge direction opposite to that of BS in order to cancel wavelength dispersion effects on the output beam The block diagram in Figure 1 6 and the description below explain how the FDO is connected electronically From the output frequency requested via the control panel the MOPO FDO electronics determines 1 what Signal or Idler input frequency is required to produce the requested doubled output wavelength ii what MOPO crys tal angle is required to generate this input frequency iii which FDO crys tal should be used to double this input frequency iv what the appropriate FDO crystal angle is and v what PB prism angle is required for directing the resultant frequency out of the MOPO FDO unit Once these values are determined the controller drives the various components to these value set tings Pos Sensor Y
108. the CALIB menu to the LOAD com mand Hold in the LOAD button until the system beeps then observe the vari ous messages that indicate the status of the loading operation When the loading is complete replace the original PCMCIA card with the new one Scroll the CALIB menu to the SAVE command Hold in the SAVE button until the system beeps When the save process is completed leave the new PCMCIA card plugged in and replace the cover Turn the system off then back on to reboot the unit with the old table values and new software Note the following To successfully perform a MOPO FDO software transfer use 2 05D c or later revision software The operating mode should be identical to that when the system was last operated using the original PCMCIA card The only excep tion to this is when a MOPO only unit is upgraded to include the FDO In this case change to the correct operating mode immedi ately All the settings that were in place using the original card including the IEEE address the baud rate the local or remote mode setting and the tracking state for both the MOPO and FDO should still be evident using the new card The user defined files that were originally saved using the SAVE function from the OPERATE menu when the original card was installed should now be transferred to the new card Appendix B BBO Frequency Doubling The table below shows the relationship between the MOPO fudamental wavelength
109. the FDO single harmonic output wavelength SHG the BBO crystal phase matching angle the non linear coefficient at that angle and the amount of beam walk off that can be expected at that angle Table B 1 Frequency Doubling in Type I BBO MOPO FDO SHG Crystal Phase der pM V Fundamental Wavelength matching Angle non linear Walkoff mm cm Wavelength output 0 coefficient 0 4000 0 2000 No solution 0 4100 0 2050 86 715 0 018 0 108 0 4200 0 2100 75 833 0 285 0 444 0 4300 0 2150 70 491 0 431 0 582 0 4400 0 2200 66 520 0 537 0 668 0 4500 0 2250 63 287 0 621 0 727 0 4600 0 2300 60 537 0 691 0 768 0 4700 0 2350 58 135 0 751 0 798 0 4800 0 2400 56 001 0 803 0 819 0 4900 0 2450 54 079 0 850 0 833 0 5000 0 2500 52 332 0 891 0 843 0 5100 0 2550 50 732 0 928 0 848 0 5200 0 2600 49 256 0 961 0 851 0 5300 0 2650 47 889 0 991 0 852 0 5400 0 2700 46 616 1 019 0 851 0 5500 0 2750 45 427 1 045 0 848 0 5600 0 2800 44 313 1 068 0 844 0 5700 0 2850 43 265 1 090 0 839 0 5800 0 2900 42 277 1 110 0 834 MOPO FDO 970 Table B 1 Frequency Doubling in Type I BBO MOPO FDO SHG Crystal Phase der pM V Fundamental Wavelength matching Angle non linear Walkoff mm cm Wavelength output 0 coefficient 0 5900 0 2950 41 344 1 129 0 828 0 6000 0 3000 40 461 1 146 0 821 0 6100 0 3050 39 624 1 162 0 814 0 6200 0 3100 38 828 1 177 0 807 0 6300 0 3150 38 071 1 192 0 800 0 6400 0 3200 37
110. the original manufac turer s warranty is extended to Spectra Physics Lasers customers When products manufactured by others are used in conjunction with Spectra Physics Lasers equipment this warranty is extended only to the equipment manufactured by Spectra Physics Lasers This warranty does not apply to equipment or components that upon inspection by Spectra Physics Lasers discloses to be defective or unwork able due to abuse mishandling misuse alteration negligence improper installation unauthorized modification damage in transit or other causes beyond the control of Spectra Physics Lasers This warranty is in lieu of all other warranties expressed or implied and does not cover incidental or consequential loss The above warranty is valid for units purchased and used in the United States only Products with foreign destinations are subject to a warranty surcharge Return of the Instrument for Repair Contact your nearest Spectra Physics Lasers field sales office service cen ter or local distributor for shipping instructions or an on site service appointment You are responsible for one way shipment of the defective part or instrument to Spectra Physics Lasers We encourage you to use the original packing boxes to secure instruments during shipment If shipping boxes have been lost or destroyed we recom mend that you order new ones We can return instruments only in Spectra Physics Lasers containers MOPO FDO 970
111. ti cal centering Place a power meter in the uv output beam path and perform a second Y DISP to the 56 crystal to maximize output power Note Finish this and all adjustment operations with the up key in order to minimize any backlash effects Perform a Y DISP on the PB prism to balance the FDO difference signal reading the center bar indicator on the vertical graph Note Following this realignment it may be necessary to perform a Y DISP of the crystal and or prism tables in the other wavelength ranges 272 345 nm and 366 440 nm as well This completes the FDO alignment FDO Alignment signal PD DL PA signal idler In Figure 5 1 FDO Optical Schematic XTL2 56 PBP XTL4 36 Residual Signal and Idler Figure 5 2 3 D Layout of the FDO 5 3 MOPO FDO 970 5 4 Chapter 6 Maintenance Preventive Maintenance The MOPO FDO has been designed for hands off operation requiring minimal maintenance The top cover protects the internal components from outside contamination and prevents unwanted stray optical radiation from escaping the system The MOPO FDO should always be operated with the top cover in place Inspect all windows daily for contamination or damage Windows should be cleaned with lens tissue and acetone any time contamination is sus pected or observed Damaged windows should be immediately replaced It is reco
112. told to do so 1 Verify TP is in its proper position for frequency doubling If frequency doubling is not desired i e either the MOPO Signal or the Idler is to be output move TP to its parking lot position so that it does not block the Signal and Idler beams from exiting their respective ports Otherwise it should be in its normal position for FDO output 2 Turn on the following GCR pump laser controls Refer to the GCR manual for details a The external cooling water supply b The seeder turn from STANDBY to ON 3 Setthe GCR mode to LONG PULSE operation 4 Pressthe GCR remote control ON button and wait for the simmer lights to turn on This indicates the flash lamps are ready to use 5 Turn the LAMP ENERGY control s to its full on position and run the GCR for about 20 minutes For oscillator amplifier pump lasers turn up the oscillator first then the amplifier Turn down LAMP ENERGY control s to the START position Switch to Q SWITCH mode Turn on the MOPO FDO controller Restore LAMP ENERGY to full on position for about 10 to 15 minutes 30 to 35 minutes total warm up time 10 Use the MOPO Monitor menu on the controller to verify the GCR out put is within 1046 of the value it had at installation If necessary per form minor adjustments of the crystal angles in the harmonic generator to ensure output is optimized Spo celo Tm 11 Use the MOPO Monitor menu to verify the master oscillator reads with
113. ts them in the order in which they are dis cussed in this chapter MODE KEYS tt OPERATE SCAN SETUP MONITOR gt OPERATE gt MOPO MONITOR Y Y MOPO SERVICE FDO MONITOR Y Y FDO SERVICE REMOTE A Brief Description The following is a short description of each menu A complete description of each follows later in this chapter The Operate Menu page 4 11 is displayed when the system is first turned on and any time the OPERATE key is pressed from any other menu OPERATE 23 0 000 MONITOR DT 460 000nm GOTO START MOVE RECALL SAVE ia Sew It displays e the actual doubled output wavelength large numbers the MOPO source wavelength small numbers The function keys allow initiation of a GOTO a SCAN a MOVE 4 7 MOPO FDO 970 4 8 a SAVE of the present settings e a RECALL of the previous settings The MOPO Service Menu page 4 13 is displayed when the OPERATE key is pressed once when the Operate menu is displayed or twice from any other menu SERVICE SETUP WVL 46 MONITOR MODE CALIB INFO M MIKE RESET 730D30 MODIFY TRK WL It displays e the MOPO mode setting output wavelength e master oscillator power the command set point of the BBO crystal e the actual relative position of the crystal The function keys allow selection of e device mode e calibration mode e feedback mode e software re
114. tup It assumes the GCR and MOPO FDO currently used were originally set up together General Procedure The following alignment procedure is provided in the event the FDO becomes misaligned It provides enough information so that it can be realigned if something is merely a little off It is not meant as a first time or major alignment No HeNe alignment is required but pinholes are supplied for possible future realignment Such an alignment is beyond the scope of this manual and should be performed by a Spectra Physics Lasers service representative Allow only qualified personnel to align your FDO The following procedure is only for the FDO Refer to your MOPO User s Manual for MOPO alignment instructions The cover must be off the unit and the MOPO must be running in order to perform this procedure DANGER HIGH POWER LASER RADIATION The Quanta Ray FDO frequency doubler is a high power laser accessory whose beam is a safety and fire hazard Take precautions to avoid accidental exposure to both direct and reflected beams Diffuse as well as specular beam reflections can cause severe eye or skin damage Always wear proper eye protection and follow the safety precautions in chapter 2 Laser Safety Refer to the beam path drawings in Figure 5 1 and Figure 5 2 for the proce dure below 1 Verify the controller is set to the appropriate doubler mode e g 730D10 2 Enter 220 for the START wavelength and 250 for END in the SCAN
115. ve Symptom The output beam shifts while tuning Possible Causes Corrective Action The FDO prism table is incorrect Optimize and rebalance the FDO crystal and PB prism at a convenient wavelength in the range of interest then set up a reference alignment target 2 to 3 m away Using this target generate a new PB prism table using a Lagrangian fit over the can range of interest 7 7 MOPO FDO 970 Symptom Problems scanning 2 x the Idler Possible Causes Corrective Action The FDO is in TRACK mode Switch to FDO TABLE mode on FDO Monitor menu Dou bled Idler scans should be performed from tables Service and Repair Replacement Parts 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 Description Part Number Coated window 0002 0540 36 BBO crystal 0449 8460 56 BBO crystal 0449 8470 Pyrodetector bi cell pcb assembly 0449 9240 Beam splitters matched pair 1 wedge 0449 9340 Roof prism 35 92 mm 0449 9470 Turning prism 0449 9480 FDO controller pcb assembly 0450 0070 Absorber 0450 0100 600 cm meniscus lens 0450 7550 800 cm meniscus lens 0450 7560 Turning prism UV 1002 0640 UV dispersion prism 1002 0640 Position sensor 4809 0364 Motormicrometer 5401 1579 MOPO
116. vision information The FDO Service menu page 4 14 is displayed when the OPERATE key is pressed twice when the Operate menu is displayed or three times from any other menu MOD IDL 0 ES WVL 230000 SET 9000 CR MONITOR SET 12038 PRE 9010 DEVICE METHOD ADJUST CONT ABORT 56 CRYS Y DISP It displays the FDO mode e the output wavelength e output power the command set point for the doubling crystals e the actual position of the doubling crystals e the command set point for the PB prism e the actual position of for the PB prism The function keys allow selection of e the device to be investigated e the calibration mode e the feedback mode Operation The Scan Setup Menu page 4 19 is displayed when the SCAN SETUP key is pressed OPERATE 230 000 460 000nm SCANS BEGIN END CONT SHOTS 101 230 000 260 000 0 0101 0 It displays e the current doubled output wavelength e the source wavelength for the doubled output The function keys provide a means to set up the number of scans to be performed e the starting and end wavelength for a SCAN e whether the scan will be CONTinuous at a user defined rate or e will dwell at user defined settings and a deliver a preset number of SHOTS at each dwell Once a scan begins progress menus are displayed for monitoring the scan The MOPO Monitor Menu page 4 23 is displayed whenever the MONI TOR key is pressed once OPERATE SETU
117. w it off with air or dry nitrogen This will help prevent damage to them If damage is present replace the damaged optics as soon as possible to prevent further damage to them WARNING If damage is present turn the system off immediately to prevent damage to the BBO crystal and other optics Notify your Spectra Physics Lasers service representative of the problem e Monitor the uv pump power on a daily basis pump power is displayed on the MOPO FDO Monitor screen Refer to the instructions in the Daily Start Up procedure for operating the GCR pump laser IMPORTANT As specified in the Daily Start Up procedure of the MOPO manual a combined warm up period of approximately 45 min utes is required before the uv power can be reliably read LLL Operation e Monitor the environmental conditions such as temperature humidity dust and drafts on a regular basis If these conditions fall outside the recommended operating range take corrective action Identifying potential issues related to environmental conditions helps ensure optimal system performance Daily Start Up Procedure This short procedure is provided to minimize your daily start up efforts The controls and display menus referred to are discussed later in this chap ter or are covered in your MOPO User s Manual This procedure assumes the system was used recently and has not been moved since that time The MOPO FDO controller should be off do not turn it on until

MOPO FDO-970 - Spectra

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