Multispecies gas detection using mid-infrared open-path Fourier transform and upconversion spectroscopy

Open-path spectroscopy is a prominent gas-detection technique for environmental studies, pollution monitoring, and leak detection. In this work, we present two distinct configurations for open-path spectroscopy utilizing the same broadband mid-infrared supercontinuum (SC) source by employing spectrometers based on Fourier transform and upconversion spectroscopy. The two spectrometers exhibit distinct performance characteristics (e.g., spectral resolution, time resolution, and spectral coverage) due to their different designs. We evaluated the performance of these configurations across a range of applications, including atmospheric gas monitoring and stand-off detection of evaporation.