A phase-stable dual-comb interferometer

TL;DR

This paper presents a method to achieve phase-stable dual-comb interferometry with mutual coherence maintained over 300 seconds, significantly surpassing previous durations, enabling advanced spectroscopy and sensing applications.

Contribution

The authors demonstrate a feed-forward stabilization technique that maintains mutual coherence in dual-comb systems for over 300 seconds, extending the coherence time by two orders of magnitude.

Findings

Mutual coherence achieved over 300 seconds.

Applicable to various frequency comb sources.

Enhanced precision in spectroscopy and sensing.

Abstract

Improvements to dual-comb interferometers will benefit precision spectroscopy and sensing, distance metrology, tomography, telecommunications etc. A specific requirement of such interferometers is to enforce mutual coherence between the two combs over the measurement time. With feed-forward relative stabilization of the carrier-enveloppe offset frequencies, we experimentally realize such mutual coherence over times that exceed 300 seconds, two orders of magnitude longer than state-of-the-art systems. Illustration is given with near-infrared Fourier transform molecular spectroscopy, where two combs of slightly different repetition frequencies replace a scanning two-beam interferometer. Our technique can be implemented with any frequency comb generators including microresonators or quantum cascade lasers.