# Computational Doppler-limited dual-comb spectroscopy with a free-running all-fiber laser

## TL;DR

This paper presents a highly simplified, low-power dual-comb spectrometer using an all-fiber laser, enabling high-resolution, broadband spectroscopy with minimal setup complexity and computational phase correction.

## Contribution

It introduces a free-running, all-fiber dual-comb laser system that is simple, power-efficient, and capable of high-precision Doppler-limited spectroscopy.

## Key findings

- Achieved <1% precision over 1.7 THz bandwidth in 200 ms
- Operates with only 350 mW power over hours
- Demonstrated effective computational phase correction

## Abstract

Dual-comb spectroscopy has emerged as an indispensable analytical technique in applications that require high resolution and broadband coverage within short acquisition times. Its experimental realization, however, remains hampered by intricate experimental setups with large power consumption. Here, we demonstrate an ultra-simple free-running dual-comb spectrometer realized in a single all-fiber cavity suitable for the most demanding Doppler-limited measurements. Our dual-comb laser utilizes just a few basic fiber components, allows to tailor the repetition rate difference, and requires only 350 mW of electrical power for sustained operation over a dozen of hours. As a demonstration, we measure low-pressure hydrogen cyanide within 1.7 THz bandwidth, and obtain better than 1% precision over a terahertz in 200 ms enabled by a drastically simplified all-computational phase correction algorithm. The combination of the unprecedented setup simplicity, comb tooth resolution and high spectroscopic precision paves the way for proliferation of frequency comb spectroscopy even outside the laboratory.

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Source: https://tomesphere.com/paper/1905.04647