Precise Spectral Measurement of Acetylene Enabled by an All-Fiber Acousto-Optic Dual-Comb Interferometer

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We report the precise measurement of acetylene spectrum using an acousto-optic dual-comb interferometer (AO-DCI) sharing the same seed laser. The AO-DCI operates without the need for locking mechanisms or reliance on nonlinear effects and, thus is particularly well-suited for precise spectroscopy applications in complex environments. In this study, we conducted a comprehensive evaluation of the frequency stability and performance characteristics of this developed AO-DCI system and subsequently applied it to the measurement of the P(11) and P(7) lines of acetylene in nitrogen. We measured the pressure-induced shift coefficient and collisional broadening coefficient of the P(11) to be −0.00869(16) cm−1/atm and 0.1614(26) cm−1/atm, respectively, and the P(7) to be −0.0092(7) cm−1/atm and 0.1795(14) cm−1/atm, respectively. We believe this system, in an easy-operation manner, would offer novel insights and methodologies for conducting precise spectroscopy and frequency measurements in complex environments.