Abstract

Infrared wavelengths from some 3μm out to beyond 10 feature strong and characteristic absorption lines of most molecules, making gas analysis with high resolution spectroscopy the main application of mid infrared diode lasers. Especially if gas mixtures are analyzed under low pressures of some 10 mbar. gas components can be detected very selectively and sensitively by this technique. At such pressures, the absorption lines are not pressure broadened, and due to the narrower residual Doppler broadening the absorption lines can be scanned individually and often without interference of other gas components. This feature makes gas analysis with tunable diode lasers an important tool for atmospheric and environmental research as well as for instance for very fast spectroscopical analysis of automotive exhaust gases.

© 1998 IEEE