Quantum Instruments Cascade Laser Starter Kit 4.3.4 Electrical model

Starter Kit Instruction Manual Description 15

4.3.4 Electrical model

The QCL can be modelised in a RC circuit.

Electrical model characteristics

The values given below apply for a 10µm

laser wavelength.

Note: Voltage and resistor values may vary

according to the type of laser.

R1 : . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . . . 10 to 20Ω when a voltage of 4 to 6 Volts is applied

R1 : . . . . . . . . . . .. . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . . . . . . . . . . 2 to 4Ω up to 10 - 12 Volts

R1 : . . . . . . . . . . . . . . . . . . . . . .. . . . . . . 10 to 20Ω over 12 Volts, after which the laser no longer operates

C1 : . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . . . . . . . . . 100pF, capacitor between the anode and the cathode

C2 : . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . . . . . . . . . . . <100pF, depending on your mounting of the laser

− −

+=+

R1

C1 C2

Fig.5: Electrical model of QCL

Contents

Main Contents Page Page Chapter 1 Identication 1.1 Document 1.2 L imited waranty Chapter 2 General 2.1 Chapter overview 2.2 Generalities 2.3 Compliance 2.3.1 Laser compliance 2.4 Glossary 2.5 Typ ographic conventions Problem Page Chapter 3 Safety Instructions 3.1 Chapter overview 3.2 Introduction 3.2.1 Principle 3.2.2 Importance of safety instructions 3.3 G eneralsafety instructions 3.4 Environmental conditions 3.5 Compliance and informa- tion Chapter 4 Description 4.1 Chapter overview 4.2 S ystem Composition 4.3 DF B and FP QuantumCascade Lasers 4.3.1 Description 4.3.2 Geometry of QC lasers If no conguration is specied, the DN pad is used. 4.3.3 Specications 4.3.4 Electrical model 4.4 L aboratory Laser Housing(LLH100) Page 4.4.3 Thermo-Electric Cooler (TEC) and PT100 connections 4.4.4 Measurement connection 4.5 QCL p ulserswitching unit(LDD100) 4.5.1 Description 4.5.2 Specications 4.6 QCL pulse switching measuring unit 4.6.1 Generalities 4.6.2 Measured voltages 4.6.3 Timing data 4.6.4 Laser peak current 4.6.5 Laser peak voltage 4.6.6 Average dissipation 4.6.7 Accuracy considerations 4.7 QCL pulser timing unit (TPG128) 4.7.1 Description 4.7.2 Specications 4.8 QCL temp erature controller(TCU151) 4.8.1 Description 4.8.2 Specications 4.8.3 Peltier and PT100 connections Chapter 5 Installation 5.1 Chapter overview 5.2 General 5.3 Packing list 5.3.1 Standard items 5.4 S etting the appropriate AC voltage on TCU151 5.4.1 Procedure 5.5 In stalling the starter Kit 5.5.1 Before beginning 5.5.2 Procedure Page Chapter 6 Use 6.1 Chapter overview 6.2 QCL pulse timing unit com- mand description 6.3 T CU151command description 6.4 L aser utilisation 6.4.1 Overview 6.4.2 Proceedings Page 6.5 Interlock utilisation 6.5.1 Before beginning 6.5.2 Procedure Interlock utilisation Chapter 7 Troubleshooting 7.1 Chapter overview 7.2 Principle The power supply reaches max cur- rent for a very low voltage Laser draws current but gives no light The laser does not draw current Chapter 8 Maintenance 8.1 Overview 8.1.1 How to remove the covers of TCU151 and TPG128 8.2 Replacement procedures 8.2.1 Quantum Cascade Laser replace- ment Page 8.2.2 QCL UP and DN p osition exchange Page 8.3 T CU151 temperature con- troller interlock setting 8.3.1 Generalities 8.3.2 Before beggining interlock set- ting 8.3.3 Needed material 8.3.4 Procedure interlock setting 8.4 Calibaration pro cedures 8.4.1 TPG128 calibration Page Page 8.4.2 TCU151 temperature controller calibration Page Page Page Page Page Page Chapter 9 Application notes 9.1 Detection techniques 9.1.1 Direct absorption 9.1.2 Frequency modulation technique (TILDAS) 9.1.3 Photoacoustic detection Chapter 10 Appendix 10.1 Bias Circut (Bias-T) 10.1.1 General 10.1.2 Description 10.1.3 Specications 10.1.4 Utilisation