# 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.

## Key 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.

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Source: https://tomesphere.com/paper/1705.04214