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arXiv · 2403.02720

A mid-infrared dual-comb spectrometer in step-sweep mode for high-resolution molecular spectroscopy

Muriel Lepère·Olivier Browet·Jean Clément·Bastien Vispoel·Pitt Allmendinger·Jakob Hayden·Florian Eigenmann·Andreas Hugi·Markus Mangold
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Abstract

To meet the challenges of high-resolution molecular spectroscopy, increasingly sophisticated spectroscopic techniques were developed. For a long time FTIR and laser-based spectroscopies were used for these studies. The recent development of dual-comb spectroscopy at high-resolution makes this technique a powerful tool for gas phase studies. We report on the use and characterization of the IRis-F1, a tabletop mid-infrared dual-comb spectrometer, in the newly developed step-sweep mode. The resolution of the wavenumber axis is increased by step-wise tuning (interleaving) and accurate measurement of the laser center wavelength and repetition frequency. Doppler limited measurements of N2O and CH4 reveal a wavenumber accuracy of 1E-4 cm-1 on the covered range of > 50 cm-1. Measured half-widths of absorption lines show no systematic broadening, indicating a negligible instrument response function. Finally, measurements of nitrogen pressure broadening coefficients in the v4 band of methane show that quantum cascade laser dual-comb spectroscopy in step-sweep mode is well adapted for measurements of precision spectroscopic data, in particular line shape parameters.

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Muriel Lepère, Olivier Browet, Jean Clément, Bastien Vispoel, Pitt Allmendinger, Jakob Hayden, Florian Eigenmann, Andreas Hugi, Markus Mangold. 2024-03-05. A mid-infrared dual-comb spectrometer in step-sweep mode for high-resolution molecular spectroscopy. https://doi.org/10.1016/j.jqsrt.2022.108239

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