Environmental applications of laser-based photoacoustic spectroscopy

The combination of tunable narrowband laser sources with the highly sensiti ve photoacoustic (PA) detection scheme bears great potential for pollution monitoring. The PA technique compares favorably with other optical methods such as multipass transmission or cavity ringdown spectroscopy. In trace ga s sensing, the main requirements are high sensitivity and selectivity, mult icomponent capability and large dynamic range. PA spectroscopy can generall y offer these features. As example the detection of ppb to sub-ppb gas conc entrations even in multicomponent mixtures and isotopic selectivity have be en demonstrated. This report discusses some main characteristics and recent results illustrated by some examples.