Fourier transform spectrometer based on high-repetition-rate mid-infrared supercontinuum sources for trace gas detection

We present a fast-scanning Fourier transform spectrometer (FTS) in combination with high-repetition-rate mid-infrared supercontinuum sources, covering a wavelength range of 2-10.5 mu m. We demonstrate the performance of the spectrometer for trace gas detection and compare various detection methods: baseband detection with a single photodetector, baseband balanced detection, and synchronous demodulation at the repetition rate of the supercontinuum source. The FTS uses off-the-shelf optical components and provides a minimum spectral resolution of 750 MHz. It achieves a noise equivalent absorption sensitivity of similar to 10(-6) cm(-1) Hz(-1/2) per spectral element, by using a 31.2 m multipass absorption cell. (C) 2021 Optical Society of America under the terms of the OSA Open Access Publishing Agreement

Automated summary

A fast-scanning Fourier transform spectrometer with high-repetition-rate mid-infrared supercontinuum sources is presented, covering a wavelength range of 2-10.5 μm. The spectrometer demonstrates its performance for trace gas detection and achieves a noise equivalent absorption sensitivity of similar to 10(-6) cm(-1) Hz(-1/2) per spectral element. Utilizing off-the-shelf optical components, it provides a minimum spectral resolution of 750 MHz.