Cavity enhanced absorption spectroscopy of multiple trace gas species using a supercontinuum radiation source

Abstract

Supercontinuum radiation sources are attractive for spectroscopic applications owing to their broad wavelength coverage, which enables spectral signatures of multiple species to be detected simultaneously. Here we report the first use of a supercontinuum radiation source for broadband trace gas detection using a cavity enhanced absorption technique. Spectra were recorded at bandwidths of up to 100 nm, encompassing multiple absorption bands of H₂O, O₂ and O₂-O₂. The same instrument was also used to make quantitative measurements of NO₂ and NO₃. For NO₃a detection limit of 3 parts-per-trillion in 2 s was achieved, which corresponds to an effective 3σ sensitivity of 2.4×10^-9 cm^-1Hz^-1/2. Our results demonstrate that a conceptually simple and robust instrument is capable of highly sensitive broadband absorption measurements.