Résumé
Mid-infrared laser diodes are highly attractive sources for gas spectroscopy applications due to the presence of strong absorption lines of many gaseous species in this spectral range. Particularly, the 2.3 – 3.3 µm wavelength range contains strong absorption lines of some pollutants as CH4, NH3 or HF while CO2 and H2O interference absorption lines are very low which renders possible the highly selective and sensitive detection of these pollutants. Vertical-cavity surface-emitting lasers (VCSELs) appear especially well adapted to be used as laser sources for absorption spectroscopy due to several intrinsic characteristics that they offer. The low threshold, single-mode operation, the circular output beam with low divergence are only some of their well-known advantages.