# Broadband photoacoustic spectroscopy of $^{14}\text{CH}_4$ with a high-power mid-infrared optical frequency comb

## TL;DR

This paper demonstrates a broadband photoacoustic spectroscopy system using a high-power mid-infrared frequency comb to detect radiocarbon methane with high sensitivity and reports the first infrared spectrum of $^{14} ext{CH}_4$.

## Contribution

It introduces a novel broadband photoacoustic spectroscopy setup with a high-power mid-infrared frequency comb for radiocarbon methane detection, achieving high sensitivity and first spectral data.

## Key findings

- Detection limit below 100 ppb for radiocarbon methane
- First infrared spectrum of $^{14} ext{CH}_4$ reported
- Potential for optical detection system development

## Abstract

We report a photoacoustic spectroscopy setup with a high-power mid-infrared frequency comb as the light source. The setup is used in broadband spectroscopy of radiocarbon methane. Due to the high sensitivity of a cantilever-enhanced photoacoustic cell and the high power light source, we can reach a detection limit below 100 ppb in a broadband measurement with a sample volume of only a few milliliters. The first infrared spectrum of $^{14}\text{CH}_4$ is reported and given a preliminary assignment. The results lay a foundation for the development of optical detection systems for radiocarbon methane.