Quantum Instruments Cascade Laser Starter Kit manual Laser draws current but gives no light

Page 37

Starter Kit Instruction Manual

Troubleshooting

Laser draws current but gives no light

-The laser may be reversed polarized (it is not a desirable situation but does gen- erally not destroy the laser).

√Check the polarity of the connection.

-The polarity is right. It draws too much current and the power meter is misaligned.

√Reduce the current at the maximum speciﬁed for the operating temperature.

√Check power meter alignement and scale.

-The QCL laser is not used with the LLH and is grounded.

√Check that there is no short-circuit on the circuit.

The laser does not draw current

-There is no contact with the laser.

√Check that the gilded copper contact is present and properly mounted.

√Tighten the PET U-shaped holder in order to eﬀective the contact with the laser by means of the POM ﬁxing screws.

√Check the connections on the LLH. Measure the input resistance with an ohm- meter between the Laser connector and the Base receptacle connector.

Image 37

Contents Instructions Manual Web version Quantum Cascade Laser Starter KitContents Troubleshooting InstallationMaintenance Overview UseAppendix Document IdentiﬁcationLimited waranty ManufacturerChapter overview GeneralGeneralities CompliancePersons GlossaryProduct PersonnelProcedure style Commands styleTypographic conventions Description styleProcedure eﬀects style ProblemSee page x-y Troubleshooting style Possible causePage Importance of safety instructions Safety InstructionsNon-compliance with the safety regulations IntroductionEnvironmental conditions General safety instructionsCompliance and informa- tion System Composition DescriptionIf no conﬁguration is speciﬁed, the DN pad is used DFB and FP Quantum Cascade LasersDescription Geometry of QC lasersSpeciﬁcations Electrical model Electrical model characteristicsLLH100 external view description Laboratory Laser HousingLLH100LLH100 internal view Laboratory Laser Housing internal viewThermo-Electric Cooler TEC and PT100 connections Speciﬁcations of the Peltier connectorMeasurement connection Speciﬁcations of the measurement connectorQCL pulser switching unit front and rear view QCL pulser switching unitLDD100Generalities QCL pulse switching measuring unitMeasured voltages Timing dataDuty cycle calculation Laser peak currentAverage dissipation Laser peak voltageAccuracy considerations QCL pulser timing unit TPG128 Trigger and logic output signals Ω TTL driver circuitPeltier and PT100 connections QCL temperature controllerTCU151Chapter overview Packing list InstallationGeneral Standard itemsProcedure Setting the appropriate AC voltage on TCU151110-120V, 60Hz USA 220-240V, 50Hz Europe Before beginning Installing the starter KitConnecting Starter Kit QCL pulse timing unit com- mand description UseTCU151 temperature controler front panel TCU151 command descriptionOverview Laser utilisationProceedings Starting the TPG128 Interlock utilisation Procedure Interlock utilisationPower supply reaches max cur- rent for a very low voltage TroubleshootingDC power supply is not ﬂoating PrincipleLaser does not draw current Laser draws current but gives no lightQCL laser is not used with the LLH and is grounded There is no contact with the laserHow to remove the covers of TCU151 and TPG128 MaintenanceOverview Quantum Cascade Laser replace Ment Replacement procedures+ LLH100 connection Facet on the case, it is extremely fragileExchanging the laser QCL UP and DN position ExchangeHumidity If the ambient atmosphere is humid this isProcedure interlock setting TCU151 temperature con Troller interlock settingBefore beggining interlock set Ting Needed materialProcedure calibration Calibaration procedures1 TPG128 calibration GeneralitiesTPG128 main board TPG128 main board Procedure +5V/-5V power supply check 2 TCU151 temperature controller calibration= 1.22 to Sensing level and range adjustementTemperature Reference oﬀset adjustment Setting Current/Voltage ratio adjustmentOscillator check LCD screen should display 1.00 aStarting the power section of the instru Ment 7V = 70 C If needed, adjust it with the trimmer P92→ Value displayed ≤ 1A Current adjustment→ Value displayed should tend to the deﬁned value → The temperature displayed 2 should be 035 C Miscellaneous functions testing Temperature Limit testingThreshold on → The red LED 1 should turn oﬀDetection techniques Application notesDirect absorption Frequency modulation technique TildasPhotoacoustic technique Photoacoustic detectionBias Circut Bias-T AppendixGeneral Utilisation What has to be kept in mind before use? Avoid reverse polarity on the input Current and voltage ranges of the Bias-T cir- cuitUnpacking instructions for NS submounts Unpacking NS laser from its transportation box