Interferogram-based determination of the absolute mode numbers of optical frequency combs in dual-comb spectroscopy

Tatsuhiro Fukuda, Makoto Okano, Shinichi Watanabe

Research output: Contribution to journalArticlepeer-review

Abstract

Dual-comb spectroscopy (DCS), which uses two optical frequency combs (OFCs), requires an accurate knowledge of the mode number of each comb line to determine spectral features. We demonstrate a fast evaluation method of the absolute mode numbers of both OFCs used in DCS system. By measuring the interval between the peaks in the time-domain interferogram, it is possible to accurately determine the ratio of one OFC repetition frequency (frep) to the difference between the frep values of the two OFCs (∆frep). The absolute mode numbers can then be straightforwardly calculated using this ratio. This method is applicable to a broad range of ∆frep values down to several Hz without any additional instruments. For instance, the minimum required measurement time is estimated to be about 1 s for ∆frep ≈ 5.6 Hz and frep ≈ 60 MHz. The optical frequencies of the absorption lines of acetylene gas obtained by DCS with our method of mode number determination shows good agreement with the data from the HITRAN database.

Original languageEnglish
Pages (from-to)22214-22227
Number of pages14
JournalOptics Express
Volume29
Issue number14
DOIs
Publication statusPublished - 2021 Jul 5

ASJC Scopus subject areas

  • Atomic and Molecular Physics, and Optics

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