High-resolution (8–16 MHz) rovibrational absorption spectra of low-pressure methanol, ethanol, isoprene, and dimethyl sulfide at 700–1500 cm-1 measured via dual-comb spectroscopy

Abstract

We employ dual-comb spectroscopy, a state-of-the-art technique that utilizes a pair of broadband mutually coherent laser frequency combs, to acquire high spectral resolution mid-infrared absorption spectra of molecules relevant to terrestrial and exoplanetary atmospheres. We have recorded room-temperature spectra of low-pressure methanol, ethanol, isoprene, and dimethyl sulfide in the 700–1500 cm⁻¹ (6.7–14.3 µm) range with the resolution down to 8 MHz (2.7 × 10⁻⁴ cm⁻¹) and with the absolute frequency accuracy of 10^–7 cm⁻¹, limited by the accuracy of a rubidium atomic clock. To date, this dataset represents the most comprehensive longwave infrared absorption spectra of these four molecules.