Simultaneous multi-gas detection between 3 and 4μm based on a 2.5-m multipass cell and a tunable Fabry-Pérot filter detector.

We demonstrated a versatile and innovative gas sensing system based on a Fabry-Pérot (FP) filter detector, which operates in the spectral range from 3.1 to 4.4μm (3226-2273cm ^-1 ) with a spectral resolution of 20nm. The developed sensor system can be used to record the entire spectrum by means of a one-time scan or, alternatively, to access selected spectral regions by using the tunable FP filter detector. A multipass cell with an effective path length of 2.5m was implemented to improve the detection sensitivity. The spectra of methane, formaldehyde and carbon dioxide were simultaneously measured, with detection limits of 200ppm, 900ppm and 20ppm, respectively. A seven-day continuous measurement for indoor carbon dioxide gas was carried out demonstrating the stability and robustness of the reported sensor system.
(Copyright © 2019. Published by Elsevier B.V.)