Abstract

The mid-infrared 2-2.5 μm region of the electromagnetic spectrum is attractive for trace gas sensing due to the presence of strong absorption bands of several species of industrial interest, including CO, CH₄, NH₃ and HF. Moreover, its location in the so-called transparency window, where absorption from the main infrared active atmospheric compounds (H₂O and CO₂) is weak¹, makes the analysis of other molecules easier. On the other way, the 2.5-2.7 pm region shows strong water vapour absorption lines making this range well adapted to water measurements and isotopic ratio studies. For this application, single-frequency and continuously tunable emission is required. DFB (Distributed FeedBack) laser diodes are hence well suited for gas sensing applications.

© 2007 IEEE