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

Muriel Lepere, Olivier Browet, Jean Clement, Bastien Vispoel, Pitt Allmendinger, J. Hayden, Florian Eigenmann, Andreas Hugi, Markus Mangold

Research output: Contribution to journalArticlepeer-review


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 10−4 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 ν4 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.
Original languageEnglish
Article number108239
Pages (from-to)108239
JournalJournal of Quantitative Spectroscopy and Radiative Transfer
Publication statusPublished - Sept 2022


  • High-resolution dual-comb spectroscopy
  • Mid-infrared
  • N2-collisional broadening of methane lines
  • Quantum cascade laser frequency comb


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