Optical frequency comb Fourier transform cavity ring-down spectroscopy

TL;DR

This paper introduces a broadband, high-precision cavity ring-down spectroscopy method using a near-infrared frequency comb and Fourier transform spectrometer, enabling calibration-free atmospheric gas measurements with high resolution.

Contribution

It presents a novel combination of frequency combs and Fourier transform spectroscopy for broadband cavity ring-down measurements, enhancing accuracy and spectral resolution.

Findings

Successful measurement of atmospheric water and CO2 absorption spectra

High frequency resolution and absorption precision demonstrated

Absorption retrieval is calibration-free and independent of cavity parameters

Abstract

We demonstrate broadband and sensitive cavity ring-down spectroscopy using a near infrared frequency comb and a time-resolved Fourier transform spectrometer. The cavity decays are measured simultaneously and spectrally sorted, leading to purely exponential decays for each spectral element. The absorption spectra of atmospheric water and carbon dioxide are retrieved and demonstrate the high frequency resolution and absorption precision of the technique. The experimental apparatus, the measurement concept and the data treatment are described. The technique benefits from the advantages of cavity ring-down spectroscopy, i.e. the retrieved absorption does not depend on the cavity parameters, opening up for high accuracy absorption spectroscopy entirely calibration-free.