Comb-Based Fourier-Transform Spectrometry for Broadband Measurements of Absorption and Dispersion

Fourier-transform spectroscopy (FTS) over the years has become the golden standard in broadband spectroscopic measurements in the infrared part of the electromagnetic spectrum, offering measurement range limited only by the detector sensitivity and emission spectrum of the light source. This method however has always had a significant tradeoff: it necessitates a mechanical travel scheme to produce an optical path difference (OPD) between interferometer arms, and the spectral resolution is set by this distance, which made the high-resolution measurements very slow and the instrumentation required for them very spacious.