Spectral distortion of dual-comb spectrometry due to repetition rate fluctuation
Author(s): Hong-Lei Yang, Hao-Yun Wei, Yan Li, State Key Laboratory of Precision Measurement Technology & Instruments, Department of Precision Instrument, Tsinghua University
Pages: 165-169
Year: 2016 Issue: 4
Journal: Chinese Physics B
Keyword: optical frequency comb; Infrared spectra; molecular spectra;
Abstract: Dual-comb spectrometry suffers the fluctuations of parameters in combs. We demonstrate that the repetition rate is more important than any other parameter, since the fluctuation of the repetition rate leads to a change of difference in the repetition rate between both combs, consequently causing the conversion factor variation and spectral frequency misalignment. The measured frequency noise power spectral density of the repetition rate exhibits an integrated residual frequency modulation of 1.4 Hz from 1 Hz to 100 k Hz in our system. This value corresponds to the absorption peak fluctuation within a root mean square value of 0.19 cm-1 that is verified by both simulation and experimental result.Further, we can also simulate spectrum degradation as the fluctuation varies. After modifying misaligned spectra and averaging, the measured result agrees well with the simulated spectrum based on the GEISA database.
Pages: 165-169
Year: 2016 Issue: 4
Journal: Chinese Physics B
Keyword: optical frequency comb; Infrared spectra; molecular spectra;
Abstract: Dual-comb spectrometry suffers the fluctuations of parameters in combs. We demonstrate that the repetition rate is more important than any other parameter, since the fluctuation of the repetition rate leads to a change of difference in the repetition rate between both combs, consequently causing the conversion factor variation and spectral frequency misalignment. The measured frequency noise power spectral density of the repetition rate exhibits an integrated residual frequency modulation of 1.4 Hz from 1 Hz to 100 k Hz in our system. This value corresponds to the absorption peak fluctuation within a root mean square value of 0.19 cm-1 that is verified by both simulation and experimental result.Further, we can also simulate spectrum degradation as the fluctuation varies. After modifying misaligned spectra and averaging, the measured result agrees well with the simulated spectrum based on the GEISA database.
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