Datasheet

CONTENTS 2

3.5.2 What is the reﬂectivity of the LLH window? . . . . . . . . . . . . . . . . . . . . . . 14

4 Operating QCLs in continuous wave mode 15

4.1 Thermal properties . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15

4.2 Modulation of a CW mode operated QCL . . . . . . . . . . . . . . . . . . . . . . . . . . . 15

4.2.1 Direct modulation of the DC source . . . . . . . . . . . . . . . . . . . . . . . . . . 15

4.2.2 Additional modulated supply . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15

5 General QCL questions 18

5.1 How to measure QC laser emission? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18

5.2 General emission characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18

5.2.1 What wavelengths can be reached? . . . . . . . . . . . . . . . . . . . . . . . . . . 18

5.2.2 Why is such a large range obtainable? . . . . . . . . . . . . . . . . . . . . . . . . 19

5.2.3 How ”CW” does a QCL look like in pulsed mode? . . . . . . . . . . . . . . . . . . 19

5.2.4 What optical powers can be expected? . . . . . . . . . . . . . . . . . . . . . . . . 19

5.2.5 How precise should emission be speciﬁed? . . . . . . . . . . . . . . . . . . . . . . 19

5.3 Tuning and linewidth . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20

5.3.1 How does a DFB-QCL tune? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20

5.3.2 How much can a DFB-QCL be tuned? . . . . . . . . . . . . . . . . . . . . . . . . . 20

5.3.3 Why is the line-width of a DFB-QCL limited? . . . . . . . . . . . . . . . . . . . . . 20

5.3.4 How and how much does a FP-QCL tune? . . . . . . . . . . . . . . . . . . . . . . 20

6 Glossary and Abbreviations 22