## 抄録

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 (f_{rep}) to the difference between the f_{rep} values of the two OFCs (∆f_{rep}). The absolute mode numbers can then be straightforwardly calculated using this ratio. This method is applicable to a broad range of ∆f_{rep} values down to several Hz without any additional instruments. For instance, the minimum required measurement time is estimated to be about 1 s for ∆f_{rep} ≈ 5.6 Hz and f_{rep} ≈ 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.

本文言語 | English |
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ページ（範囲） | 22214-22227 |

ページ数 | 14 |

ジャーナル | Optics Express |

巻 | 29 |

号 | 14 |

DOI | |

出版ステータス | Published - 2021 7月 5 |

## ASJC Scopus subject areas

- 原子分子物理学および光学