Mid IR diode lasers for diode laser trace gas analysis

Given the typical output powers of contemporary mid IR diode lasers of well below a mW up to a few mW at best, absorption spectroscopy is the typical analysis technique, using these light sources. Both central laser features. low bandwith and single spatial mode emission. are essential for diode laser trace gas analysis. Mid IR diode lasers are around a long time, they are one of the oldest laser types. Their development has been slow as compared to e.g. the visible and near IR diode losers made from III-V compounds like GaAs. This is due to the fact that they did not offer wide spread commercial or defense application. Their use for some specialized gas analysis tasks and (most prominent) environmental trace gas analysis allowed only limited development effort. In view of the vast difference of development funds, by orders of magnitude, the mid IR diode lasers however for sure do not have to hide: their typical requirement of long term 10(exp minus 6) wavelength stability is by for no t met better by typical III-V lasers. A major development step leading to laterally structured diode lasers has been made with funding from the EUROTRAC-JETDLAG programme. This contribution is meant to report the development goals and results. The first part is concerned with the spectroscopic application and the resulting demands on the diode lasers. The second focuses on the technical realization, and the resulting laser performance.