Dual-comb cavity-mode width and shift spectroscopy. (January 2022)

• Record Type: Journal Article
• Authors: Charczun, D.; Nishiyama, A.; Kowzan, G.; Cygan, A.; Voumard, T.; Wildi, T.; Herr, T.; Brasch, V.; Lisak, D.; Masłowski, P.
• Is Part Of: Measurement. Volume 188(2022)
• Publication Date: 2022-01
• Subjects: Optical frequency combs -- Frequency comb spectroscopy -- Dual comb spectroscopy -- Cavity-enhanced spectroscopy -- Precision spectroscopy -- Molecular spectroscopy -- Gas sensing; Weights and measures -- Periodicals; Measurement -- Periodicals; Measurement; Weights and measures; Periodicals; 530.8
• DOI: 10.1016/j.measurement.2021.110519
• Languages: English
• ISSNs: 0263-2241

Abstract

Highlights: The first cavity mode-width and dispersion measurement with a dual-comb technique. 13 kHz-wide cavity resonances measured with Hz-level precision. Simplified experimental setup compared to previous demonstrations of the techniques. Rapid measurement promises applications in molecular dynamics and gas sensing. Abstract: Optical frequency comb spectrometry has become one of the leading fields devising new ways to investigate molecular structure and characterize optical elements due to its advantage in speed and accuracy. In this work we demonstrate the first dual-comb realization of cavity mode-width and mode-dispersion spectroscopies, achieving single-spectrum acquisition time in millisecond range, maintaining high spectral resolution limited by the comb tooth width. Interleaving of a few tens of spectra allows us to measure shapes of 13 kHz-wide enhancement cavity modes and determine their widths and positions with Hz-level precision. Thanks to this we can simultaneously measure the loss and dispersion of both the cavity and the intracavity medium. As a demonstration, we measure spectra of a gas mixture of methane and nitrogen and compare them with a simulation based on the HITRAN database. This novel method has many possible applications, including gas metrology, high-reflectivity mirror characterization or trace gas sensing.