Frequency-comb-referenced mid-infrared source for high-precision spectroscopy

Abstract

We report on a tunable continuous-wave mid-infrared optical parametric oscillator (OPO), which is locked to a fully stabilized near-infrared optical frequency comb using a frequency doubling scheme. The OPO is used for 40 GHz mode-hop-free, frequency-comb-locked scans in the wavelength region between 2.7 and 3.4 μm. We demonstrate the applicability of the method to high-precision cavity-ring-down spectroscopy of nitrous oxide (N₂O) and water (H₂O) at 2.85 µm and of methane (CH₄) at 3.2 μm.