Trace gas monitoring by laser photoacoustic spectroscopy and related techniques (plenary)

Trace gas sensing systems have to meet several requirements like high detection sensitivity and selectivity, multicomponent capability, field suitability, etc. In this respect devices based on tunable lasers combined with appropriate detection schemes are attracting great interest. This report reviews recent developments demonstrating the potential of such systems. The performance of various spectroscopic systems with different lasers (gas lasers, nonlinear optical sources like optical parametric oscillators and difference frequency generation, near-infrared external cavity diode lasers, quantum cascade lasers) and different detection schemes (photoacoustic, multipass transmission, cavity ringdown) is discussed and illustrated with examples from various areas. Applications include laboratory analyses of multicomponent samples with isotopic selectivity, field measurements in ambient urban and rural air or even at volcanic sites, as well as investigations in the area of biology and medical diagnostics. (C) 2003 American Institute of Physics.