Low-cost dual-comb spectrometer for CO2 monitoring based on gain-switched semiconductor lasers

Dual-comb spectroscopy (DCS) is an emerging technique that has attracted the attention of the research community due to its fast data acquisition and high-spectral resolution properties. Despite its versatility and mechanical stability, the complexity and cost of high performance DCS are still experimentally challenging. We propose a simple and compact DCS system that significantly reduces system costs by incorporating three low-cost key components: direct digital synthesizers and step recovery diodes in the signal generator to operate the lasers under gain-switching regime, and a software-defined radio as a digitizer. The viability of this configuration is demonstrated by performing DCS measurements of carbon dioxide (CO2), with a standard deviation of residual error of only ∼ 0.01. These results will pave the way to the commercial availability of compact, high-resolution DCS systems.