Saturated-absorption cavity ring-down spectroscopy

TL;DR

This paper introduces a novel saturated-absorption cavity ring-down spectroscopy technique that enhances sensitivity and precision, enabling detailed measurements of molecular hyperfine structures with unprecedented accuracy.

Contribution

It presents a new method for cavity-ring-down spectroscopy that decouples background and absorption signals, improving measurement accuracy and enabling hyperfine structure analysis of molecules.

Findings

First measurement of hyperfine structure of an excited vibrational state of $^{17}$O$^{12}$C$^{16}$O

Achieved measurement accuracy of a few parts in $10^{-11}$

Demonstrated high sensitivity and frequency precision in spectroscopic applications

Abstract

We report on a novel approach to cavity-ring-down spectroscopy with the sample gas in saturated-absorption regime. This technique allows to decouple and simultaneously retrieve empty-cavity background and absorption signal, by means of a theoretical model that we developed and tested. The high sensitivity and frequency precision for spectroscopic applications are exploited to measure, for the first time, the hyperfine structure of an excited vibrational state of $^{17}$O$^{12}$C$^{16}$O in natural abundance with an accuracy of a few parts in $10^{-11}$.