Compact fiber coupled gas sensor tunable from 3.3-4.4 /spl mu/m

Summary form only given. In trace gas detection based on absorption spectroscopy there is a need for widely tunable narrow bandwidth mid-infrared light sources. Diode lasers which have desirable operating characteristics for field based laser spectroscopy, are presently only available in the spectral region from 0.63 to 1.6 /spl mu/m. However, these can be frequency shifted into the midinfrared spectroscopic fingerprint region by nonlinear difference frequency mixing. A robust, compact and widely tunable fiber coupled mid-infrared sensor suitable for the sensitive, selective and real-time detection of various trace gases was described. Issues such as power scaling, portability and high-resolution spectroscopy will also be discussed.