Sensitive Multi-species Gas Sensing with Supercontinuum-based Photoacoustic Spectroscopy

Abstract

Photoacoustic spectroscopy (PAS) is a sensitive gas sensing technique widely used for single species detection in small sample volumes [1] . The operation principle of PAS relies on the conversion of electromagnetic radiation into acoustic waves by the modulation of the light source, which results in periodic light absorption and detectable pressure variations. Broadband PAS required for multi-species detection can be realized by combining a light source with a wide spectral coverage with a scanning Fourier transform spectrometer, which simultaneously generates a distinct modulation frequency for each wavenumber of the source. Beyond thermal light sources [2] , Fourier transform photoacoustic spectroscopy (FT-PAS) with a cantilever-enhanced pressure detection has been demonstrated using supercontinuum (SC) and optical frequency comb sources for improved sensitivity and spectral resolution [3] - [5] .