Abstract

Quartz-enhanced photoacoustic spectroscopy (QEPAS) was introduced in 2002 and quickly became one of the most popular methods for laser-based trace-gas detection. The general principle of all PAS-based methods is that when modulated radiation is absorbed by gas particles, the absorbed energy is converted into heat resulting in the thermal expansion and contraction of gas particles and the creation of an acoustic wave. In QEPAS, the piezoelectric quartz tuning fork is used to convert an acoustic wave into an electrical signal.

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