Quantum Technology Instruction Manual for Model HVP-51-DIFF-5

8/13/2019 Quantum Technology Instruction Manual for Model HVP-51-DIFF-5

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108 Commerce 8 t , Suite101,Lake Mary, Florida, 327464212. USAFAX 407-33343S2 PHONE 407-333-8348 TO LL FREE 800-232-4291EIMAILstaff@qiiantii intech.com INTERNET http:/ /www.quantumtech.com

INSTRUCTION MANUALFORMODELHVP-5I-DIFF-5W/QS-3-2H

SN:E02-159
mailto:[email protected]://www.quantumtech.com/http://www.quantumtech.com/mailto:[email protected]


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HVP-5I-DIFF DRIVER OPERATIONS MANUAL

THE INFORMATION CONTAINED HEREIN IS THE PROPERTY OF QUANTUMTECHNOLOGY, INC. AND MUST NOT BE DUPLICATED IN WHOLE OR IN PART,FOR OTHER THAN INTERNAL EVALUATION PURPOSES. IT SHOULD NOT BEDISCLOSED TO OTHERS WITHOUT PRIOR EXPRESS WRITTEN PERMISSION OFQUANTUM TECHNOLOGY, INC.

WARNING: ALL SAFETY PRECAUTIONS MUST BE OBSERVED.UNPACKING INSTRUCTIONS

1. Check the package for damage before accepting it. Ifpossible, refuse badly damaged packages. Notify thecarrier as well as Quantum Technology, Inc.

2. Check the contents of all packages against the packing slip.Missing items will be replaced immediately by QuantumTechnology, Inc.

F:\common\wp51\inanuals\hvp5i(3if .man Rev4/18/013:00pm


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INSTALLATION

INITIAL INSPECTION;If the shipping carton is damaged, ask the carrier's agent to bepresent when the system is unpacked. Check the electronicspackage for external damage such as broken or bent controls orconnectors, and dents or scratches on the cabinet. Inspect themodulator for broken connectors or damaged windows. Check theperformance of the system as soon as possible after receipt.

If damage is evident, notify the carrier and the nearest salesoffice. The sales office will arrange for repair or replacementof the system without waiting for settlement of a claim with thecarrier. For other than initial inspection warranty claims,contact the sales office.

INPUT POWER;The system was wired for either 100, 115, 208 and 230 VACoperation depending upon how the system was specified at the timeof order. The rear panel label will indicate the input power thatyour system recjuires. The system is supplied with a threeconductor power cable. The offset (round) pin on the power cableconnector is the ground pin and it should be connected to asuitable ground.


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GENERAL;The HVP-5I-DIFF driver system uses the following components:

1 - HVP-590, -510, OR -595 Driver1 - DVM display module1 - HVPS high voltage supply which may be 50XX

type (5 KV set, 6 KV internal limit) or 90XX type(9 KV set, 10 KV internal limit)

1 - DDl,DDl-1,or DD2 divider/delay for timing1 - DIN5-DIN5-6' cable1 - SHV-SHV-RG59-6' cable

The system is useful for Pockels cell shutters, mode locked pulseextraction and cavity dumping applications.Additional cables maybe supplied for the specific hook-up diagram,which should be consulted.

HOOKUP CONNECTIONS;Connect the system as shown on the cabling diagram included at theend of this section. After completing the connections, place thepockels cell in the optical path such that it is aligned with thelaser beam. Use low power for safety when aligning the opticalpath. The system is now ready to be turned on.


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DVM DISPLAY

The digital volt meter on the front panel is used to monitorimportant parameters within the system. When a module is selectedby pushing the select button on its front panel, the meter willrelease any other module it is monitoring and switch to theselected module. For this system the DVM can monitor only thehigh voltage. When the button is pushed on the high voltagemodule, the meter is scaled to read the peak value of the highvoltage pulse that will be produced when the system is triggered.This indicated value is usually less than the actual high voltagebeing generated by the high voltage supply.


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MODEL 40SE-HVP HIGH VOLTAGE POWER SUPPLY

The 40SE-HVPS series plug in modules are high voltage powersupplies consisting of a regulated low voltage power supply, aregulated high voltage power supply with associated control, andmeter monitoring and switching circuitry. A 400 VDC bias outputis also provided.

CONTROL AND OPERATION;HVP Output: This is the high voltage output to the pulser. Theload should be connected before turning on power to the system.The SHV connector on the HV output may arc if this is not done.

HV Adjust: This 10 turn dial sets the HV as displayed by themeter on the main power supply/meter plug in. This indicates thepeak level of the high voltage output pulse.

HV Push Button: This push button toggles the HV ON and OFF asindicated on the front panel LED. When this push button is firstdepressed, the meter displays the HV set by the HV adjust, and theHV is ON. When it is depressed a second time the HV is turnedoff. This button has another purpose. If another plug in hasselected the meter for its own display, depressing the buttondeselects the meter from that function and causes it to displaythe high voltage reading.

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THEORY OF OPERATION;This power supply consists of four sections. The first is themeter switching and high voltage enable and control circuits. Thesecond is the high voltage supply, and the third is the 24 VDCsupply that provides primary power to the high voltage supply. Thefour is the 425 VDC bias output. Refer to the schematic 21-547-FIK and the layout drawing 21-547-F400.

Meter Switching and High Voltage Enable and control:The meter switching circuit works as follows: When front panelswitch Sl is depressed, the meter buss line is connected toground. This action disengages all other plug in modules from themeter, and both sets and presets one of the flip flops in Ulcausing both output pins 5 and 6 to go high. It also produces apulse through the capacitor C4 that toggles the other flip flopsin Ul causing pin 9 to go low. This enables the high voltage asthe analog switch, U2 , pins 11 and 15 which are connected to thehigh voltage power supply remote input are now removed from groundand connected to the front panel "HV ADJUST" control.

On the release of Sl, the first flip flop, which is being both setand reset, is left preset as the capacitor, C16, holds the presetvoltage on pin 4 for a few msec after the set voltage on pin 1 hadbeen removed. The same action controls the decimal point readingto show the correct decimal point position, DP2 . This is

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accomplished via Ul pin 6, Q bar output going low which also turnson the 10,000:1 HV sample (by output dividers RIO through R12) anddirects that to the meter. RIO is the meter calibrationadjustment. When the display switch is depressed a second time,Ul is clocked and toggles turning off the high voltage as pin 9goes high. Pin 6 remains low keeping the meter connected to thisfunction.

The 24 VDC power supply is a standard 115 VAC to 24 VDC chopperconverter that supplies power to the high voltage supply. Itcomes on when the 40SE-PSM system AC switch is turned on.

This module accepts a variety of high voltage power supplies. Theyvary in output voltage from 3 KV to 10 KV and in output currentfrom less than 1 MA to over 6 MA depending upon the systemrecjuirements.

The 400 VDC bias output consists of a rectifier diode, a filtercapacitor, and a bleeder resistor. This produces a low currentoutput that is used by the pulser trigger circuits.


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MODEL DDl DIVIDER DELAY UNIT

The Model DDl Divider Delay Unit - The DDl unit allows precisedivider settings of 6 decades enabling MHz signals to be divideddown to sub Hz rates. An alternate method of operation is to usethe 6 decade settings to select precise pulse bursts counts out inboth manual and external trigger modes. Programmed delays canalso be generated. One of the more useful applications isdividing down mode lock signals to the rep rates required. Theunit features high sensitivity for mode lock signals and twoprecise independent 1-99 nsec digitally settable delay outputs.One of the delayed outputs can be delayed up to an additional 900nsec in 100 nsec steps. The unit can also be used as signalgenerator by operating it from its internal oscillator.

INSTRUCTIONS;INPUT: The inputs are fed to the front panel through BNCconnectors. On some special units, the input may be fed via BNCrear panel connectors. The input sensitivity is from 0.20 to 1volt peak to peak so as to allow direct coupling to conventionalpulse generators, mode lock signal sources, or even opticallygenerated pick off signals.


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INTERNAL / EXTERNAL MODE; This mode selects the master clocksource, which is either the internal 2 ^ MHz oscillator or anexternal input. External clock frecjuencies up to 240 MHz areaccepted. Operation on the internal oscillator is the same as ifthe unit was operating on a 240 MHz external clock.

DIVIDER MODE; In the divide mode the six decade push button thumbwheel switches are utilized for setting the precise divisionrequired for the mode locked signal. The external clock isdivided by 10 by a high speed scaler before entering theprogrammed divider which makes the division selected 10 more thanis indicated by the front panel decade switches. Here the dividerdelay will produce three continuous outputs the direct output "ADVOUT",the delayed output "OUT 1", and the delayed output "OUT 2".

DELAY MODE; In the delay mode the unit will produce a pulsedelayed from the "BURST" input or for a selected manual SS-BURSTinput by an amount ecjual to 10 times the six decade switch settingtimes the selected clock single cycle time. The OUT 1 and OUT 2outputs are delayed additionally by their respective settings. Theinternal clock is ecjuivalent to 240 MH z.

BURST MODE; In the burst mode the unit will produce a burst of"N"pulses for each pulse on the "BURST" input or for a selected

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manual SS-BURST. The pulse count is ecjual to the number set onthe six decade switches, and the output frecjuency is ecjual to theclock divided by 10. The OUT 1 and OUT 2 delayed outputs are alsoactive but will not be useable if the delays selected exceed 5times the clock cycle time. The positive edge triggered "BURST"input is TTL level compatible and capacitive coupled to a 50uload.

DELAY; The delay thumb wheel switches allow additional precisedelay setting of the OUT 1 output up to 99 nsec and the OUT 2output up to 999 nsec in one nsec increments. Up to 5 nsecadditional continuously adjustable delay is also provided for eachoutput. This is useful, for example, in setting the timing of apicked out pulse in a mode locked pulse train to coincide exactlyat the precise time recjuired when the appropriate pulse is at thecorrect optical path position in the modulator.

OUTPUT; All outputs of the delay unit are capable of drivingapproximately 3 volt peak to peak in to a 50 ohm load and areapproximately 50 nsec wide. These outputs are TTL compatible, buthigh levels will reach approximately 7V peak if no other externalloads are present.

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THEORY OF OPERATION;The clock input, via J2, is amplified by a gain of 7 through thehigh speed amplifier Ull. Ull increases the sensitivity foroptical pick off applications and for direct mode lock signalconnections to conventional mode lock sources. The amplifiedsignal out of Ull is fed to U2 , which is a high speed divide, by10 counter. This combination allows signals of up to 240 MHz tobe accepted. The output of U2 is fed to the clock select logicwhere it or the internal 25 MHz oscillator becomes the source forthe divider chain. This selection is made by the front panelINT/EXT switch (Sll on the schematic). The clock is fed to thefirst two counters of the six divide by 10 counters, U3 and U4,and to the mode select decoder U13. The Most significant bit (Q4)output of U4 is fed to U5 through US to become the clock for theremaining four counters. Pull up resistors on BCD switches S2through S7 direct the selected BCD inputs to the divider chain forcontrolling the divide ratio, delay, and the burst count.

In the divide mode the decoded terminal count of the BCD countersat the output of U9 pin 6 is sent to the output section throughthe mode select decoder U13. It also reloads the BCD switchsetting into the counters on the fly providing a continuous outputequal to the counter input frecjuency divided exactly by the BCDswitch setting. U13 is an eight to one multiplexer, with onlythree inputs used, controlled by a three bit binary code. In the

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Q output as pin 9 this enables the first nand gate, U23, at pin 2.The second gate, which drives the output, is connected as aninverter as both inputs are connected together. When this signalgoes high it is coupled through the two nand gates in U23 andappears as the ADV OUT Pulse. This signal is also connected tothe flip flop clock, pin, 11 through R37, a 2K resistor. The 51PF capacitor, C36, connected form this clock input to groundcauses a delay before the high level can toggle the flip flop. Ittakes the capacitor about 50 nsec to charge up to the clockthreshold level. At the end of this delay the flip flop toggles,and its Q output goes low. This inhibits the first nand gateforcing its output high which is inverted by the second nand gatecausing the ADV OUT level to go low forming a 50 nsec high level'output. Diode CRl and resistorR3 6form a cjuick discharge pathfor C36. This is necessary, as the pulse width will be shorter ifC3 6 is not discharged completely before the next pulse occurs.This circuit will follow the demultiplexer output for rep ratesthat are to fast to allow the flip flop to toggle.

The OUT 1 and OUT 2 signals are formed by programmable delayscontrolled by six bit binary code inputs. These binary inputs aregenerated from the front panel decade switches through proms UIOand U19 coded to produce a decimal to binary conversion. Pull upresistors on BCD switches S8 and S9 provide the input delaysetting to the BCD to binary converter UlO. UlO provides the

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conversion necessary for the timer delay generator, U2 1. S12 andS13 provide the input delay setting to the BCD to binary converterU19. U19 provides the conversion necessary for the timer delaygenerator, U12. These are precision delay generators that canproduce addressable timing delays of 1 through 99 nsec in 1 nsecincrements. The output of U12 goes through the invertor, U2 0then through the driver, U23 to OUT 1 at J5. The pulse width iscontrolled by delaying the reset pulse to the timer delaygenerator. Once triggered the output of the timer delay will gohigh after the set delay and stay high until it is reset. Thereset line is connected to the output through resistor RIO. The51 PF capacitor, C37, connected form this reset input to groundcauses a delay before the high level at the output can cause areset. It takes the capacitor about 50 nsec to charge up to thereset level. At the end of this delay the output of the timerdelay goes low removing the high at the output. R14 is a delaycalibration range adjustment for the timer delay, U12, and isnormally adjusted for a 99 nsec delay when the front panel delaysetting is set to 99 nsec.

The 0 to 99 nsec delay for the OUT 2 pulse is generate the sameway as that for the OUT 1 above except that the U21 timing delayis used. R15 is a delay calibration range adjustment for this.The 100 to 900 nsec delay is an additional function which alsoaffects the pulse width delay circuit. The output of the timer

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delay, U21 is connected to nand gate Ul at pin 9 and to theprecision delay generator input, U26 at pin 1. It is alsoconnected to the 10 input of the 8 to 1 multiplexer U26. U22 andU2 6form a 10 to 1 multiplexer. If the output has been low forsome time all outputs from the precision delay will be low, andthe output of the multiplexer will be low. This signal isconnected to the other input of the nand gate, Ul at pin 10.Since it is initially low it will force the output of nand gate Ulhigh at pin 28 and inhibit the high level output from the timerdelay from getting through. This keeps the OUT 2 output low. Thehigh level from the timer delay does go to the precision delay,U25, and to the multiplexer 10 input. The precision delay willproduce outputs along its delay line at 100 nsec intervals. Theseare sequentially connected to the multiplexer such that the binarycode of 0000 through 1001 (decimal 0 through 9) generated by themost significant digit of the front panel delay switches willselect delay outputs of 0 through 900 nsec. Note that the 0 nsecconnected to 10 of U26 is just the timer delay output. The twomultiplexers can be connected in parallel as shown, as they aretri-state devices. The enable line is the most significant bit ofthe delay select code from the switch.

When the selected delay time is passed through to the output, theoutput of the multiplexer goes high. This opens the nand gate, Ulallowing its output to go low. This output is inverted by the

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output driver nand gate and becomes the delayed OUT 2 output.The high from the multiplexer is connected to the timer delayreset through R21 and C38 to produce the desired pulse width asdescribed for OUT 1 above.


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MODEL HVP-51-DIFF PULSERGENERAL;The HVP-5I-DIFF pulser is a dual high voltage fast rise timepulser. It accepts a high voltage DC input and produces a pulsethat goes from the high voltage level to ground on the output thatreceives a trigger. A differential pulse up to 8000 Vp 20 nsec inwidth can be generated by sending a trigger to each input phased20 nsec apart. Pulse rates are limited by the capacity of thehigh voltage power supply and load capacitance with frecjuencies upto 5000 PPS being typical. Higher frecjuency units and units withinverted outputs are available by special order.

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TROUBLESHOOTING FLOW CHARTWARNING UNAUTHORIZED REPAIR MAY VOID THE WARRANTYFollow the flow chart below to isolate a failure to the plug in module lev el. The drawingshows the internal adjustments and test points available when the top cover is removed.

YESWILL THE UNIT TURN ON ?

REMOVE THE COVER

CHECK THE DC VOLTAGES ON THELABELED LINES ALONG PRINTED BACKPLANE PANEL WIRINGG O O D

BAD

REMOVE ALL MODULES EXCEPT THE DVMDISPLAY

TURN OFF POWER AND PLUG IN THE NEXTMODULEFUSE

OK

F U S E / V O L T A G EBADTURN ON POWER

F U S E / V O L T A G E S O KTURN OFF POWER AND PLUG IN ANOTHERMODULE

PROBLEM IS IN THIS MOD ULE. SEE THESCHEMATIC IN THE MANUAL

NO

O K CHECK THE FUSES

B L O W N

REPLACE THE FUSE ANDTURN ON AGAIN

B L O W SA G A I N

REMOVE ALL MODULES EXCEPTTHE DVM DISPLAY AND REPLACETHE FUSE

TURN ON POWER AGAIN

F U S E B L O W S

PROBLEM IS IN THE POWER SUPPLY ORCABLES ON THE CONNECTOR PANEL

INSPECT FOR DAMAGE OR A LOOSEWIRE

POWER IS OK. TROUBLE IS INONE OF THE OTHER UNITS. SEESCHEMATICS IN THE MANUAL.


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SYSTEM TOP VIEW WITH COVER OFF

SYSTEMDVMMODULE

- --< Gnd+-< -15V+-< +5V+-< +15V+-< +24V

J

Ooo

HIGHPOWER

R6RIOR14

VOLTAGESUPPLY

O

O

DIVIDERDELAY

R14

R15

BLANK

L

FRONT

ADJUSTMENT LOCATIONR6 HV SUPPLYRIO HV SUPPLYR14 HV SUPPLYR15 DIVIDER DELAYR14 DIVIDER DELAY

FUNCTIONLOW LIMIT ADJMETER CALHIGH VOLTAGE LIMITDELAY 2 CALDELAY 1 CAL

* High voltage limit for HVPS-9003** Low voltage limit for HVPS-9003

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T O POCKELS C E U REARH V P - 5 9 0 D - R(SHOWING OPTIONAL MHV CONNECTORS)


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DDl OPTIONAL

SYNC OUTPUT TO E^ NTMP

TRIGGER INPUT FOROPTIONALBURST ANDOE UY FUNCTIONS

HVP-5XX-DR PULSERWITH INTERNAL Q-SWITCHBEAM INPUT(TYP) BEAM OUTPUT(TYP)

HVP-5I-DIFF DRIVER WITH Q-SWITCHCABLE INTERCONNECTION

04/11/02NiltVivpfildlff.dwo


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E O M O D U L A T O R

Horizontal

- 4 . 3 8 -

Vee Clamp

Vee Block

Vert ical Adj

vertical clami

M OD EL: M TM M OU N T WI TH EOM

SIZEA

PSCM NO

SCALE 1 : 1

DWQ NON/A

SHEET 1 OF 1

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MAIN CABINET POVIER SUPPLY TEST DATA

Work Order No: E02-159Customer: Univ. of CA

DATE: 8/26/02S/N: E02-159

Shipped Line Voltage:ELECTRICAL TEST:MODEL PSM POWER SUPPLY/METER:

M CABINET (63 HP).

VAC

SWITCHER LINEARL CABINET (84 HP)_v/ STANDARD LINEARXL CABINET STANDARD LINEARFusing: 100 VAC220 VACTested line voltageVOLTS AT: 100 VAC-1-20 to -1-28 V Supply+ 15 V Supply:-1- 5 V Supply:- 15 V Supply:Other DC Supplies:

50 VAC Supply:3 50VAC Supply:T2-4,T2-5 117VAC fanT2-1,T2-2 lOOVACT2-1,T2-3 117VACFor 220V T2-3, T2-4

Meter cal 1500mv:Decimal point: DPI

DP2DP3

A Slo Bio_A Slo Bio

117VAC VN/A VDC15.:5.-1524.

63372117104117

L VDCD2 VDC.04VDCD3 VDCVDCVACVAC.5 VACVAC.5 VAC_ VAC

_.000_0.0000.0

117250

12.

OK

VACvAC

220VAC

5 AA

DVM

5 AA1

Slo BioSlo Bio

240VACVDCVDCVDCVDC

VACVACVACVACVAC_ VAC

Reading

Comments

Checked By:F:\C0MM0N\WP51\1TESTDAT\PSM.DAT

1^Rev 1/17/02 9:15ain
http://c0mm0n/WP51/1TESTDAT/PSMhttp://c0mm0n/WP51/1TESTDAT/PSM


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23-flU9-029:29:02( 8 : f lve rg9e ih58 ns9.9nV

40 sijps^

50 ns RIS1 1 0 nV m2 2 V 5B

) ^ m i ^ t f m

i 5 nsp e r i o d ( C 'u id th (C)riseCC)Fai1(C)de l 9 u ( C '

M M p m ^ W M W+ H W M V M t t a M | 4t+1- -H- a -H - +t-

237.68 ns3.85 ns4.89 ns115.22 n s

E x t i e DC 1.0 0 V50fi

t+-

STORE WFORMS

DO STORE1 - > H 1 ) s t o r e

D 2fl BC Df i l l d i s p l s y e d

, t ol i D H 2 H 3 K 4Flpu

10GS/sD flUTO

Detected Optical ResponseSN:E02-159D


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DATA SHEET 40SE-HVPS HIGH VOLTAGE POWER SUPPLY

Date: 8/26/02Ser No. E02-159A

Work order: E02-159Customer: Univ. of CA

ModelModelModelModelModelModelModelModelModelModelModel

Number _NumberNumberNumberNumberNumberNumberNumberNumberNumberNumber

HVPS-HVPS-HVPS-HVPS-HVPS-HVPS-HVPS-

V HVPS-HVPS-HVPS-HVPS-

-3006-6005-5006-9003-1060-6010-50606040-9012-5001-9006

3KV,5KV,6KV,9KV,IKV,5KV,5KV,6KV,9KV,5KV,9KV,

6.6ma5 ma6 ma3 ma60 ma12 ma60 ma40 ma12 ma1 ma6 ma

TEST DATA:Meter calibration & DPX.XXHV limit dial at 10 if providedHV disable checkBias voltageREMOTE/LOCAL optionSlow ramp up option Yes

Test By:

J-5.1-

OKKVOK

320 VDCN/A OK VDC MAX=V No

KV

F:\C0MM0N\WP51\ITESTDAT\HVPS.DAT Rev 04/1/02 1:00 pm
http://c0mm0n/WP51/ITESTDAT/HVPShttp://c0mm0n/WP51/ITESTDAT/HVPS


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Date:DATA SHEET DIVIDER/DELAY MODEL DDl-D

8/26/02 Work orcier: E02-159

ser No. : E02-159B Customer: Univ. of CA

PARAGRAPH3.13.23.23.33.33.43.53.63.63.63.63.73.73.73.83.93.103.113.123.133.143.143.143.15

Signature

TEST PASSED/VALUEDivide by 10 scaling ADV OUTDelay 2, OUT 2 pulse widthDelay 2, 10 to 90 NSEC stepsDelay 2, 1 to 9 NSEC stepsDelay 2, 1 to 25 NSEC vernierOUT 2 900 NS delayMax frequency 0 NSEC delayDelay 1, OUT 2 pulse widthDelay 1, 10 to 90 NSEC stepsDelay 1, 1 to 9 NSEC stepsDelay 1, 1 to 25 NSEC vernierBurst mode externalBurst mode external 3 pulse groupsBurst mode external max frequencyBurst mode manualDivider count accuracySensitivity 50 MHZ inputDivider max frequencyInternal clock frequencyInternal clock delay burstInput to ADV OUT delayADV OUT to OUT 2 delayDivide count delayDelay mode check

5065

NSNS

OKOK2590047050

NSNSMHZNS

OKOK34 NSOK10

440MHZMHZ

OKOK35

45025

MVppMHZMHZ

OK11165

NSNS

OKOK

F:\C0MM0N\WP51\1TESTDAT\DD1-NEW Rev 11/7/0110:00 am
http://c0mm0n/WP51/1TESTDAT/DD1-NEWhttp://c0mm0n/WP51/1TESTDAT/DD1-NEW


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Date:DATA SHEET DIVIDER/DELAY MODEL DDl-D

8/26/02 Work order: E02-159

Ser No. : E02-159C Customer: Univ. of CA

PARAGRAPH3.13.23.23.33.33.43.53.63.63.63.63.73.73.73.83.93.103.113.123.133.143.143.143.15

Signature

TEST PASSED/VALUEDivide by 10 scaling ADV OUTDelay 2, OUT 2 pulse widthDelay 2, 10 to 90 NSEC stepsDelay 2 , 1 to 9 NSEC stepsDelay 2, 1 to 25 NSEC vernierOUT 2 900 NS delayMax frequency 0 NSEC delayDelay 1, OUT 2 pulse widthDelay 1, 10 to 90 NSEC stepsDelay 1, 1 to 9 NSEC stepsDelay 1, 1 to 25 NSEC vernierBurst mode externalBurst mode external 3 pulse groupsBurst mode external max frequencyBurst mode manualDivider count accuracySensitivity 50 MHZ inputDivider max frequencyInternal clock frequencyInternal clock delay burstInput to ADV OUT delayADV OUT to OUT 2 delayDivide count delayDelay mode check

5060

NSNS

OKOK2890044050

NSNSMHZNS

OKOK30 NSOK10

430MHZMHZ

OKOK35

44024.9

MVppMHZMHZ

OK11055

NSNS

OKOK

F:\C0M0N\WP51\1TESTDAT\DD1-NEW Rev 11/7/01 10:00 am


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OS SERIES POCKELS CELLS INTRUCTION MANUAL

1.0 SCOPEThis is an instruction manual for the installation andalignment of Quantum Technology's QS Series Pockels Cells,whether used in shuttering applications such as pulseslicing and extraction or for Q-switching.1.1 INTROCUTIONThe Pockels Cell Q-switch can produce laser pulses of shortduration (typically 6-50nsecs depending upon systemconfiguration) and high peak power by storing energy in thelaser rod for the first half of the flashtube pulse and thenreleasing it. This is achieved by applying a high voltageacross the crystal in the Pockels cell. This voltage causesrotation of the polarization of the laser beam, which thengoes through a polarizing filter. The effect is a change inintensity of the beam. The Pockels cell, in conjunctionwith the polarizing filter, thereby acts as an electro-opticshutter and inhabits lasing. Removal of this high voltage,after a period set to maximize the stored laser energy,results in the Q-switched laser pulse.In pulse slicing or extraction of pulses from a mode-lockedpulse train, the Pockels cell is placed external to thelaser (between two crossedpolarizers). A fast high voltagepulse will result in selection of the laser pulse that iscoincident with the high voltage. Widening the high voltagepulse would result in the selection of more than one pulseif so desired.1.2 GENERAL CHARACTERISTICSThe Pockels cell is a sealed unit with anti-reflectioncoated windows at each end centered with the crystal facesto minimize disturbance of the beam path. The void betweenthe window and the crystals is filled with diry nitrogen sothat there is no moisture to effect polish of the crystalfaces, since BBO is hygroscopic. The Pockels cell ishermetically sealed to ma.ke it leak-proof. The largest ofthe QS series Pockels cells, Model QS-6-2, has a 6mmaperture recjuiring two BBO Crystals to keep VV4 to areasonable level, single VA is inversely proportional tocrystal length and directly proportional to wave-length andcrystal thickness.This device is to be used only as an intra-cavity Q-Switch.The HW version is water cooled so as to handle up to 150watts.


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All Quantiim's Pockels cell utilize high cjuality, strain-freecrystals. The crystals of the QS series are plated withtransverse electrodes for uniform electric fields andresistivity is greater than lO" ohm-cm.1.3 CAUTIONARY NOTE

APPLICATION OF A CONTINOUS DC VOLTAGE TO THIS POCKELSCELL COULD RESULT IN ITS PREMATURE FAILURE.The following parameters are the maximumvoltages for all Quantum Technology Pockels Cells: allowable

POCKELS CELLSERIES CRYSTALMATERIAL MAXIMUM VOLTAGE

QC KD*P lOKV Pulses W/Maximum3 DutyRatioNo DC'. QS-3,QS-4,

QS-LN

NOTE 1:

QS-3-2QS-4-26-2

AC Volt,

BBOBBOBBO

LiNbO

ages ir

5.2KVAC or DC7.2KVAC or DC

2,3

7.2KVAC or DClOKV AC or DC

2,3

jxcess of 3% duty ratio (>1 sec.)or DC voltage may cause premature failure due tomigration of electrode material into the crystalmaterial, causing thermal runaway. It issuggested that a quarterwave plate be used betweenthe Pockels cell and the rear laser mirror.

NOTE 2: AC Voltages in excess of 3% duty ratio (>1 sec.)or DC voltage may result in a temporary shift inoptical transmission when placed betweenpolarizing optics. This will be seen as a slowdrift in transmission over a 1-10 minute intervaland may be compensated for by re-adjusting theapplied voltage. This effect is more pronouncedin LiNbOj than in BBO Pockels cells.NOTE 3: The maximum voltages for BBO Pockels cell isdifferent for different apertures because thebreakdown of the applied voltage occurs across theaperture.


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POCKELS CELL/MODULATOR QUICK SET-UP

This alignment procedure consists of actually four sections.Section A is to be used when the Pockels cell and polarizeroption is ordered. These will have been factory aligned andmounted together. Section B is the complete opticalalignment for the Pockels cell and optional polarizer. Youwill need Vee block or optical mount capable of X, Ytranslation, pitch, yaw and rotation about the optical axis.Section C is the complete optical alignment for pulse pickeror extra cavity applications when supplied without apolarizer. Section D is the optical alignment forintracavity Q-Switch applications.',

SECTION A: Pockels Cell/Modulator with Polarizer FirstTime Alignment Instructions1. Perform these instructions if the Pockels cell andpolarizer were already prealigned by the factory andwere not disturbed.2. Hook up all the cables to modulator and accessories perthe interconnection diagram supplied with themodulation system. If a system was not supplied, thenattach the Pockels cell to driver or drive source to beused.3. Insert the modulator into a suitable optical mount.4. Rotate the modulator so the connectors are vertical.

Critical adjustment will be done later.5. Center the laser beam in the aperture of the modulatorso the beam is exiting cleanly. Lower the laser powerto less than lOOmW.6. Fix a white paper as a target about 1 meter down theoptical path from the modulator. Place a pencil dot toshow beam center on the paper.7. Apply a piece of scotch invisible tape to the input endcaps to diffuse the beam.8. A bulls eye pattern will appear as shown in figure 3.This is the familiar "Maltese Cross" as observed inuniaxial birefringent crystals when illuminated in theoptic axis (or Z axis) direction.9. Using the pitch and yaw axis adjustments of the mount,align the cross pattern centered on the dot as show infigure 1.


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10. Remove the diffusing tape and measure the opticaltransmission with a power meter.11. Minimize the optical transmission by rotating the cellabout the beam axis, trying not to disturb themodulators pitch or yaw adjustments.12 . Ensure that the cell is still aligned by repeatingsteps 7, 8 and 9.13. The beam power should be very close to an opticalminimum. Slight adjustments in pitch and yaw mayfurther reduce the observed minimum. This will be bestdone by observing the minimum under dynamic conditionsas observed on an oscilloscope using a high speed photodetector.14. This completes this alignment procedure.

SECTION B: Pockels Cell and Polarizer Alignment Instructions1. Perform these instructions if the Pockels cell andpolarizer alingment was disturbed or needs to berealigned.2. Remove the polarizer from the Pockels cell by looseningthe set screw(s) that is attaching it to thecell.3. Hook all the cables to the modulator and accessoriesper the interconnection diagram supplied with themodulation system. If a system was not supplied, then

attach the Pockels cell to driver or driver source tobe used.4. Place the polarizer crossed to the input beam.5. Insert the Pockels cell into a suitable optical mountbefore the polarizer.6. Rotate the modulator so the connectors are vertical.Critical adjustment will be done later.7. Center the laser beam in the aperture of the modulatorPockels cell so the beam is exiting cleanly. Lower the

laser power to less than 100 mW.8. Fix a white paper as target about 1 meter down theoptical path from the modulator. Place a pencil dot toshow beam center on the paper.9. Apply a piece of scotch invisible tape to the input endcaps to diffuse the beam.


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10. A bulls eye pattern will appear as shown in figure 3e.This is the familiar "Maltese Cross" as observed inuniaxial birefringement crystals when illuminated inthe optic axis (or Z axisdirection).11. Using the pitch and yaw axis on the mount align thecross pattern centered on the dot as shown in figureAl.12. Apply a high voltage DC to the modulator by one ofthreeways:

1. From the High Voltage DC power course output onthe controller.2. By feeding a constant DC 5 volt level to thecontroller input to enable the HV driver to outputon at DC.3. Use another external HV DC supply.

13. Measure the optical power through the modulator with apower meter.14. Adjust the voltage going to cell so that a minimumtransmission is obtained.15. Maximize the transmission by adjusting the cellrotationally about the beam axis trying not to upsetthe modulators pitch or yaw adjustments.16. Adjust the applied voltage to ensure that the

transmission is at maximum.17. Ensure that the cell is still aligned in pitch and yawdirections by repeating steps 7, 8 and 9 and settingthe applied voltage to zero.18. With the voltage off and the diffusion tape removed,the beam should be very close to an optical minimum.Slight adjustments in pitch and yaw may further reducethe observed minimum. This will be best done byobserving the minimum under dynamic conditions asobserved on an oscilloscope using a photo detector.19. Measure the optical minimum.20. Remove the polarizer from the optical mount and attachit to the modulator. Rotate the polarizer till theminimum in step 17 is attained.21. Repeat step 16 to ensure the cell is aligned at aproper minimum.


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22. This completes this alignment procedure.

SECTION C: The Pockels Cell/Modulator for Pulse Picker,Extra Cavity Applications.These instructions are for Pockels cells or modulators asyour particular case may be.1. Hook up all the cables to modulator and accessories perthe interconnection diagram supplied with themodulation system. If a system was not supplied, thenattach the Pockels cell to driver or drive source to beused.2. Insert the modulator into a suitable optical mount. AVee block with pitch and yaw adjustments works best.3. Rotate the modulator so the connectors are vertical.

Critical adjustment will be done later.4. Center the laser beam in the aperture of the modulatorso the beam is exiting cleanly. Lower the laser powerto less than 100 mW, (typically).5. Fix a white paper as a;target about 1 meter down theoptical path from the modulator. Place a pencil dot toshow beam center on the paper.6. Apply a piece of scotch invisible tape to the input endcaps to diffuse the beam.7. A bulls eye pattern will appear as shown in figure 3.This is the familiar "Maltese Cross" as observed inuniaxial birefringent crystals when illuminated in theoptic axis (or Z axis) direction.8. Using the pitch and yaw axis adjustments of the mount,align the cross pattern centered on the dot as shown infigure 1.9. Remove the diJ? fusing tape and usually or by an opticalpower meter, fine tune modulator for the best opticalminimum. Recheck steps 7, 8 and 9 to check if you arenot significantly off the center of the cross.10. If HV DC is available to be applied, then with the DCvoltage (or HV pulse) applied observed the level on apower meter (oroscilloscope). If not then perform theobservation with a HV pulse and oscilloscope.11. Rotate the cell about the optical axis without changingthe pitch or yaw axis. A Vee block with pitch yawadjustments, works best.


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12. The total range of motion should not be more than -i-/-5 degrees. Lock the cell rotation when the optimumrotation position is determined. It may be necessaryto check steps 7, 8 and 9 again in case the pitch oryaw moved.13. This completes this alignment procedure.

SECTION D: Pockels cell Alignment For Intracavity Q-SwitchApplications.

1.4. PITCH/YAW ALIGNMENTFor proper operation of the PockelsCell,the cell has to bepositioned so that its optic axis is aligned to the beam towithin 10 seconds of arc. Moreover, the X and Y axis ofthe crystal must be set parallel and perpendicular to theplane of polarization of the laser. The X and Ycrystallographic axis of the crystal is horizontal when thehigh voltage connectors are horizontal. Parallelism betweenthe crystal optic axis and the input laser beam is alsoimportant. This is achieved by mounting the Q-switch in anoptical mount with three deg'O^ees of freedom along the X, Yand Z.


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P O C M U A T I O N O U K C T IO NO f n S M

W X O T X n O NO N 2 n 4 P A S S1 H I1 0U .C H ( O M

l A S U R O O

P 0 1 M I 2 I XIC IA K A n V A U D P RIS M )

F i g . 1( l U C N T O M W T A T I O N f W Q S W I T C H I N G

CIRCULARLY.POLARIZED45 ROTATION

A typical arrangement of components is shown in Fig. 1. Theinclusion of the polarizer is required if the laser rodoutput is not strongly polarized. Its presence, however,does improve system performance by raising the threshold forspontaneous emission.1. Install the Pockels Cell so that the connector isaligned either parallel or perpendicular to thepolarization plane of the laser.2 . Set up a HeNe alignment laser F i g . 2 ) so that it iscollinear with the pulsed laser beam.3. Place a gelatin polarizer P (Polaroid sheet HN 32 orsimilar) between the Pockels Cell and the Q-switchprism polarizer so that polarizer P and prismpolarizer have their polarization planes parallel toeach other.4 . Place another gelatin polarizer, P crossed to this incontact with the other face of the Q-switch.5. Place a diffuser between the HeNe laser and inputpolarizer Pj crossed to this in contact with the otherface of the Q-switch.6. Place a diffuser between the HeNe beam projected ontothe white screen.A pattern consisting of a central black cross surrounded byconcentric rings will appear on the screen. The optic axisis perfectly aligned when the bright central HeNe spot fallson the point of symmetry of the pattern as shovm in F i g .3.It may be helpful to remove the Q-switch prism polarizerduring this alignment. Also, it may be necessary to movethe diffuser and the screen back and forth to obtain theclearest image on the screen. Which will appear brighter ifthe laboratory lights are switched off.


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1re SCREEN V E R I PASS

POLARI2ERVERT. .PASS^KX:KELS'CELLRIZ.. PASSIFFUSER

HE-NE'EASER

EAR MIRRORTYPICAL ARRANGEMENT'-FOR' SETTING niJ-OF-POCKELS'CEa

P i g . 2

PATTERN OBTAINED WITH CORRECTLYALIGNED POCKELS' CELL.

CENTHAL HE.'F]E":s:pOT.

P i g . 3

- 9 -


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1.5 ROTATIONAL POCKELS CELL ALIGNMENTThe following procedure should be followed for furtherimprovement of the rotational alignment of the Pockels Cell.1. Rotate the polarizer Pj through 90 so that itspolarization plane is parallel to that of Pj. Thecentral pattern on the screen will now consist of fourdark areas disposed about the center and at an angle of45 to the vertical and horizontal (Fig. 4 ) .2. With the bias control set at a minimum, connect thePockels Cell to the drive unit and switch on the unit.Gradually raise the bias voltage while observing thepattern projected on the screen.3. Slowly rotate the PockelsCell,which causes two of thedark areas in the projected pattern to move towardseach other along the 45 axis (Fig. 4B). The PockelsCell is correctly adjusted when they merge to form adiamond shape at the center.If unattainable, set polarizer P crossed to polarizer P andrepeats the procedure for Lateral Pockels Cell Alignment(para. 1. 4) .Figure 5 is the pattern attained with the full voltageapplied, resulting in maximum extinction.

Fig.4 Fig.5


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1.6 SWITCH NOT ES:1. On all pockels cells the damping method to hold thePockels cell must be isolated from ground to withstand

I O K V : metallic surfaces must not be in direct contactwith the Pockels cell. If the pockels cell is to reston a metallic surface. The plastic body and/or anyfill screws must be installed from the base by .015"thick kapton sheet or equivalent.1.7 WATER-COOLED CONNECTIONQS-Series Pockels Cells with a "W" suffix in its modelnumber are water-cooled devices recjuiring a source offlowing water, at a rate of 1 - 2 liters per minute. Thiswater should be de-ionized to prevent the build-up of scale,and, at the least, be filtered. Increase the water flow sothat the water leaving he Pockels cell is close to roomtemperature with the Pockels cell operating at the desiredpower.WARNING: COPPER TUBES HAY CARRY HV CHARGE UNDER PULSED HVOPERATIONThe water should be de-ionized also, because under pulsed HVoperation, the copper tubes may develop a HV charge. Fasterrisetime is observed if the copper tubes are not grounded,or not shorted by the use of non-de-ionized water. If it isnecessary to ground the tubes, a pin socket on the curvedend of the tubes may be used to connect to the ground lug onthe driver rear case.Connection to the Pockels cell is with V4" inside diameterflexible tubing and a hose clamp. Right angle /4" hoseadapters are supplied to these brass connect to yourflexible tubing. Please orient the direction of couplingsbefore tightening them dovm as they "swage" dovini permanentlyon the copper tubing of thecell.1.8 SINGLE CRYSTAL VERSIONS OF THE QS-6-2-HWIn these types of cells, the cells are provided as "matched"set. The single crystals within each cell are mounted closeto the curved end of the water connectors on the cell. Inso doing, the curved ends of the cells should face eachother. As required, a cjuaterwave plate may be placedbetween the 2 cells. The + and - labels on the cellsindicate that pairs, S/N ending in A and B, 2.C and D should have the same wire connection to the driver.That is, the + of cells, A & B should go to the same driveroutputs (either Out 1 or Out 2) for example and so on. Ifcell A and D need to operate with each other, then, it maybe necessary to interchange the wires going to the -t-'s and -

11


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*s and determine the correct phasing for this new set, (the-I-of one may have to connect to the - of the other one forproper operation). For optical alignment the pitch and yawof each cell will have to be adjusted independently.1.9 WARRANTYPlease do not attempt to take the Pockels cell apart. Incase of any problem, contact our Engineering staff. ThePockels cell is guaranteed for a period of three months fromthe date of invoice and may be returned to our ServiceDepartment within the warranty period. Please obtain priorauthorization and proper shipping instructions beforereturning any device. We reserve the right to eitherrepair, replace of refund any failed device, at our option.For KD*P, or AD*P Pockels either QS or QB Series:Operation of the Pockels cell by applying DC voltage or aduty cycle resulting in greater than 3H average AC voltageacross the cell may cause premature failure and voids thewarranty.Quantum Technology reserves the right to make changes ondetails of the design and/or construction of any device,either before or after delivery, so as to ensure the highestquality of that device.

f:\common\wp51\manuals\qswitche.man Rev. 3/22/02 2:15pm

12
http://common/wp51/manuals/qswitche.manhttp://common/wp51/manuals/qswitche.man


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Q U A N T u n 7a(GaQaik@ n aoa.108Commerce Street, Lake Mary,FL32746-6212+407-333-9348 FAX: +407-333-9352e-mail: Staf [email protected] WEB: quantumtech.com

POCKELS CELL TESTINGGENERALThis manual contains general testing of Pockels cells produced by QuantumTechnology. It is a useful guide for alignment within a system as well as, a QCaid for incoming inspection, and basic failure analysis.

APARATUS ( recommended)OPTICAL BENCH OR RAILTWO POLARIZERS (see text)ONE TEST LASER - Preferred HeNe @ 633nm ~1mW CWONE DETECTOR for use within wavelength of test laserONE DISPLAY - for detector, either a meter or oscilloscopeONE RO LL OF TRAN SLUC ENT TA PE - l ike Scotch invisible tapeONE NEGATIVE LENS - Approximately -25mmGIMBALL MOUNT TO ADJUST POCKELS CELL while under testPOCKELS CELL - to be testedPOCKELS CELL'S TEST DATA SHE ET - supplied with the Pociiels ceilWRITING MATERIALWHITE PIECE OF CARDBOARD OR PAPERLASER POWER METERWhen familiar with testing Pockels cells, more specialized testing may be setupfo raparticular app lication.
mailto:[email protected]:[email protected]://quantumtech.com/http://quantumtech.com/mailto:[email protected]


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DANGERHigh Voltage HIGH VOLTAGE POWERSUPPLY

Input po lar izer (PI)

LASER BEAMIN

T Output polarizer (P2)>c POCKELSCELL UNDERTEST

AA d j u s t\'0

J-

dJMBAL MOUNT

DetectorOUT

DETECTORDISPLAYGENERAL SETUP FOR POCKELS CELL TESTINGFigure 1

INPUT/OUTPUT POLARIZERS - for this test they can be sheet polarizers if thetest laser is in the visible range between 633nm (HeNe) and ~ 532nm . A CWpower level of between 0.5mw~ 1mW is recom men ded. For reference, all tests inthis procedure used 633nm-wavelength laser.GIM BAL MOUN T - for YAW and PITCH adjustment of the Pockels cell.Rotational motion is not nece ssary, if the terminal are carefully placed in the "up"position as shown in the above drawing.DETECTOR a nd D ETECTOR DISPLA Y - these devices are to be capable ofindicating the intensity level of the source laser without sa turating. Aphotodetector and oscilloscope or a low-level power meter can be used for thispurpose.HIGH VOLTA GE POWER SUP PLY - the range of this supply is up to 9KVdepending of the Pockels cell under test. This voltage is dangerous c an belethal. Experienced personn el should only perform these tests . In som e casesthe Pockels cell driver can be used as the high voltage sou rce, see theinstruction ma nual for the particular unit used.


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POC KELS CE LL UND ER TE ST - The Pockels cell under test can be one of thethree basic models produced by Quantum Techn ology. The QC -series is KD*P ,the QS-series is BBO , and the LN-series is lithium niobate. See table below forapproximate halfwave voltages for 633nm . Consult the Pockels cell data sheetfor the test voltage use d for the particular cell.

QC'series(KD*P)~ 4 K VAperture: 6mmQS-se ries(BBO)~ 8.1 KVAperture: 6mm

LN - series(Lithium Niobate)~ 1 . 4 K VAperture: 6mmVOLTAGE COMPARISON TA BLENOTES:1) The larger the Pockels cell aperture - the greater the voltage2) Dual crys tal Pockels cells for QC and QS series require half the voltage show nIn the above table.

TESTING THE PO CKELS CE LL@ 6 33 nm - OUTSIDE OF A LASER SYSTEMThese tests are usually performed for e ither a) inspection of a new or repairedPockels cell,or b) determination of the proper operation of a Pocke lscell. If thePockels cell is in a laser system , please refer to that portion of the manu al forproper setup.Remove any protective end caps from the cell,and ca refully visua lly inspect thatthe cell is clean and clear by looking through it. Double check the s erial numberagainst the data sheet provided to aid in setup the testing param eters.Use two suitable polarizers, which are crossed polarized to each other. Let P Ibe in the same polarization as the input laser beam . Use vertical polarization forthe input laser beam . P1 can be eliminated if the test laser has a polarizationratio greater than 100:1.Set up the optical system as shown in figure 1.Ma/ce sure tlie h ig li voltage powe r sup ply isOFFan d dischargedbefore co nne ction to the Pockelscell.This manual references a HeNe laser at1mW for these tests, and recommendsthis method. The detector and display m ust be able to clearly show the minimumand maximum chang es in laser beam intensity. A photodiode (biased) and anoscilloscope works very well. A low light power m eter for 633nm is acceptablealso.


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Align the optical system such that the laser beam go es through the center of thePockels cell (bore sighted) and falls directly on the active portion of the detector,with P2 remov ed. Note - be assured that P2, if not a sheet polarizing filter, doesnot displace the beam a ppreciably on the detector. If it does, com pensate for thedeviation whe n necessary. W hen P2 is replaced, (make sure it is crossed to theinput polarization), observe the detector display.Place a piece of translucent m aterial such as "invisible" Scotch tap e or lenstissue before P I . It is also recomm ended that a negative lens be placed alsobefore P I (with the tape) to expand the beam for easy obse rvation. Place awhite cardboard or paper sheet (paper target) in from of the detector for visualobservation of the pa ttem referred to as the "Maltese cross".

Input polarizer (PD

LASER BEAM

OVapp l ied Output polarizer (P2)Paper Target

POCKELSCELL UNDERTEST i ^ro iIMBAL MOUNT

DETECTORDISPLAY

The paper target should show a projection assketched here. The concentric circles shouldbe as "round" as possible; The intersectionof the cross must also b e coincident w ith thelaser beam that wa s bore sighted initially.

Idea l d isp layed crossAt this point the high voltage will be brought up to a value as show n in the datasheet sent with the Pock elscell. Increase the voltage slowly, and never exceedby 20 % the value shown on the data sheet. W hile observing the paper target,increase the voltage until the cross ope ns, as shown in ske tch.


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TRANSMISSION LOSSIt is recom mende d that this test be performed at the w avelength at which thePockels cell is to be used, since other wavelengths will produce errors becauseof the AR coating lose. Use a power level between Im W and 10mW.In this test, a laser power meter is required. Set the pow er to the properconditions.With the cell remo ved, measure the laser output power.Without any polarizers, PI and P2, and with the cell disconnec ted from the HighVoltage Power Supply measure the output and record the power level from thedisplay with the beam going through the center of the P ockelscell.Be ca reful toalign the cell to the be am , so that it is bore sighted throu gh the center of thecell.Measure the power, and calculate the loss. It should be 4 - 5 % less.

NOTE: The previous test - TESTING THE POCKELS C ELL @ 633 nm -OUTSIDE OF A LASER SYSTEM - can be run at the actual wavelength, butkeep the power low in CW mo de. Som etimes this is not practical.

SETUP OF A POCKELS CELL OPRATING A QUARTERWAVEVOLTAGE UTILIZING A QUARTERWAVE PLATEINA LASERCAVITY

1 6 7Basic generic setup of a laser cavity{For reference - therearemany other configurations dependingonapplication)Where:

1 - Rear Mirror (Usually 1005 @ A2 - Quartenwave plate3 - Pockels cell4 - Polarizer (if necessary)

5 - Laser Head6 - Shutter/Spatial filter7 - Front mirror/output coupler


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In this configuration the Pockels cell (See: Basic gen eric se tu p of a lasercavity - sketch) is operated in the quartenwave voltage (~ Vaof the halfwavevoltage), and with no voltage app lied to the cell until Q-switching is required. ThePockels cell used sho uld have all ready been acce pted as a work ing unit.To setup the Pockels cell in an actual cavity, use a H eNe laser carefully alignedto the laser rod with all optical elements in place. Som etimes, it is easier to addone element at a time and adjust accordingly as other pieces are secu red to theoptical rail.Make certain that the laser system is OFFDefuse the HeNe laser (tape) and place target paper at the front mirror towa rdsthe laserhead. Rem ove the shutter and spatial filter. Be assu red that the"Maltese cross" is centered on the bore sighted He-N e, W ith all elemen tsreplaced,the laser is ready for testing.In simple terms, to obtain a GIANT pulse (Q-switched laser) two factors must beadjusted". The voltage on the Pockels cell which controls the polarizationrotation, and the delay of the Q-switch trigger. The delay sets up the point atwhich the P ockels cell receives a signal allow to rotate the polarized light of thelaser to create the GIANT pulse.With the flash lamp O N, the po pulation inversion takes place in the lasermedium. However, the rear mirror is block because of the quarterwave plate.Since no voltage is across the P ockels cell the polarized light goes through thecell unaltered. The light gets rotated by the quartenwave plate, reflects off therear mirror, retums again through the quartenwave plate, being rotated an again.Wh en it reaches the polarizer it is orthogonal (90-degrees) or crossed to it, andthe polarized light does not pass. Therefore, no lasing action. W hen a highvoltage is applied to the Poc kels cell at the quartenvave voltage, the light, whichwas unaltered before, now rotated by a quarterwave . Then pa ssing through thequarterwave plate, it is rotated a complete halfwave, a nd is reflect back by therear mirror. Ente ring the quartenwave plate and Pocke ls cell it is rotated again byhalfwave. Now it passes through the polarizer, and lasing begins. Since thecavity was blocked, the lasing medium has built up greatly, and the suddendischarge of photons produce the GIANT pulse.

PAD CiAPPICATIONS-POCKELS CELL TESTING


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QUANTUM TECHNOLOGY, INC.TEST DATA SHEETQ-SWITCH

CUSTOMERMODELSERIAL NOW/O NO

UNIV. OF CA.QS-3-2HQ02-159Q02-159

SAN DIEGO

CRYSTAL PARAMETERSMATERIALAPERTURE (mm.)TERMINALSHOUSINGCUSTOMER DRAWING NO.

BBO3TTBLACK DELRINNA.

OPTICAL QUALITY CONTROLTRANSMISSION AT 1064nm.CONTRAST RATIOHALF-WAVE VOLTAGE @ 632.8 nm. (KV.)

NA.>1000:12.0

PHYSICAL PARAMETERSINDEX MATCHING FLUID: N2AR COATING (nm.) : WINDOWS: CRYSTAL 633-1064 INPUT800 INPUT 633-1064 OUTPUT800 OUTPUTCOMMENTS:TESTED BY:

^ ^DATE: 8/7/2002


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QUANTUM T ECHN OLO GY . INC.108 COMMERCE ST., SUITE 101,LAKE MARY, FLORIDA 32746TELEPHONE: 407) 333-9348 FAX: 407) 333-9352E-MAIL:STAFF gQUANTUMTECH.COMCERTIFICATE OF COMPLIANCECUSTOMER NAME: UniversityofCalifornia, San DiegoPURCHASE ORDER NUMBER: 10211621MATERIAL DESCRIPTIQN: Pockels cell. Mount. Driver & PulserMODEL NUMBER: OS-3-2H. MTP-1000. HVP-5I-DIFF & HVP-525D-R-50KSERIAL NUM BER: 002 -159 . E02-159E. E02-159 & E02-159DITEM QUANTITY: ofea.COMMENTS:Also shipping cables:MHV-PT-RG62-18 (qtv.2). 5PIN DIN 5DIN-3CO ND -6 '(qtv.l). SHV-SHV-RG59-6Yqtv.n. BNCM-BNCM-RG188-6 '(2). AC Cord & Instruction M anual ,QUANTUM TECHNOLOGY INC. , HEREBY C ERT ME S THAT THE PRODUCTORDEVICESLISTED HAVE BEEN INSPECTED TO , AND AREINCONFORMANCE WITH CUSTOMER'SSPECinCATIONS ASDEFINEDINTHE PURCHASE ORDER AND RELATED DOCUMENTATION.ALL APPROPRIATE DATA SHEETS AND RELATED DO CUMENTATION ARE ENCLOSED.
http://gquantumtech.com/http://gquantumtech.com/

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Quantum Technology Instruction Manual for Model HVP-51-DIFF-5

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