Phase-stabilized 100 mW frequency comb near 10 {\mu}m

TL;DR

This paper reports a high-power, phase-stabilized mid-infrared frequency comb near 10 μm generated by a tunable optical parametric oscillator, enabling precise molecular spectroscopy.

Contribution

The authors demonstrate a phase-stabilized, tunable 100 mW frequency comb near 10 μm using a novel OPO based on AgGaSe2, with both repetition rate and offset frequency phase-locked.

Findings

Achieved 100 mW average power at 8.5 μm wavelength.

Successfully phase-locked repetition rate and offset frequency.

Tunable from 8.4 to 9.5 μm for spectroscopy applications.

Abstract

Long-wavelength mid-infrared frequency combs with high power and flexible tunability are highly desired for molecular spectroscopy, including investigation of large molecules such as C60. We present a high power, phase-stabilized frequency comb near 10 {\mu}m, generated by a synchronously-pumped, singly-resonant optical parametric oscillator (OPO) based on AgGaSe2. The OPO can be continuously tuned from 8.4 to 9.5 {\mu}m, with a maximum average idler power of 100 mW at the center wavelength of 8.5 {\mu}m. Both the repetition rate (frep) and the carrier-envelop offset frequency (fceo) of the idler wave are phase-locked to microwave signals referenced to a Cs clock. We describe the detailed design and construction of the frequency comb, and discuss potential applications for precise and sensitive direct frequency comb spectroscopy.