Mid-infrared feed-forward dual-comb spectroscopy at 3 $\mu$m

TL;DR

This paper demonstrates advanced mid-infrared dual-comb spectroscopy at 3 micrometers, enabling high-resolution, long-coherence measurements for precise molecular analysis in the gas phase.

Contribution

It introduces a dual-comb spectroscopy technique with coherence times exceeding half an hour in the 3-μm region, enhancing precision and broad spectral coverage for molecular spectroscopy.

Findings

Coherence times >30 minutes between combs.

High signal-to-noise ratio and broad spectral bandwidth achieved.

Negligible instrumental line-shape contribution to spectral profiles.

Abstract

Mid-infrared high-resolution spectroscopy has proven an invaluable tool for the study of the structure and dynamics of molecules in the gas phase. The advent of frequency combs advances the frontiers of precise molecular spectroscopy. Here we demonstrate, in the important 3-{\mu}m spectral region of the fundamental CH stretch in molecules, dual-comb spectroscopy with experimental coherence times between the combs that exceed half-an-hour. Mid-infrared Fourier transform spectroscopy using two frequency combs with self-calibration of the frequency scale, negligible contribution of the instrumental line-shape to the spectral profiles, high signal-to-noise ratio and broad spectral bandwidth opens up novel opportunities for precision spectroscopy of small molecules. Highly multiplexed metrology of line shapes may be envisioned.