High-sensitivity coherent dual-comb spectroscopy with single-cavity dual-comb OPO operating at 250 MHz

Abstract

Dual optical frequency combs, consisting of a pair of modelocked lasers with a slight difference in their pulse repetition rate, are valuable tools for high-resolution infrared spectroscopy. Heterodyne mixing of the two combs down-converts the optical comb lines to the radio frequency domain, allowing for straightforward comb-line-resolved measurements with a single photodiode [1]. Practical deployment of this technology faces significant challenges, including the complexity of the light source due to the need for two highly coherent combs, accessing a broad wavelength range in the mid-infrared, and obtaining high-sensitivity measurements despite the fact that the optical power is spread out over a large number of lines.