Fourier transform spectrometer based on high-repetition-rate mid-infrared supercontinuum sources for trace gas detection
M. A. Abbas, Khalil Eslami Jahromi, Mohammadreza Nematollahi, Roderik Krebbers, N. Liu, Getinet Woyessa, Ole Bang, Laurent Huot, Frans J. M. Harren, Amir Khodabakhsh
Abstract
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 µm. 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 ∼10 −6 cm −1 Hz −1/2 per spectral element, by using a 31.2 m multipass absorption cell.