Field applications of dual frequency comb spectroscopy

Abstract

The output of a laser frequency comb is composed of 100,000+ perfectly spaced, discrete wavelength elements or comb teeth, that act as a massively parallel set of single frequency (CW) lasers with highly stable, well-known frequencies. In dual-comb spectroscopy, two such frequency combs are interfered on a single detector yielding absorption information for each individual comb tooth. This approach combines the strengths of both cw laser spectroscopy and broadband spectroscopy providing high spectral resolution and broad optical bandwidths, all with a single-mode, high-brightness laser beam and a simple, single photodetector, detection scheme. Here I will touch on the application of this system for open-path measurements of atmospheric trace gases (CH4, CO2, CO, NH3, water, ethane, and N2O) and volatile organic compounds (acetone, isopropanol, propane) with field applications targeting industrial oil and gas monitoring and agriculture.