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arXiv · 2602.23812

Comb-locked cavity ring-down spectroscopy of CO2 at 2-micron wavelength

Muhammad Asad Khan·Vittorio D'Agostino·Stefania Gravina·Livio Gianfrani·Antonio Castrillo
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Abstract

We report on a comb-locked cavity ring-down spectrometer developed for high-precision, SI-traceable, molecular spectroscopy of air-broadened CO2 gas samples. The experimental setup relies on the use of a singly-resonant optical parametric oscillator that acts as an intermediate link between a 2 micron external-cavity diode laser and an optical frequency comb stabilized against a GPS-disciplined Rb-clock. Absorption spectra of the R(50) ro-vibrational component of the CO2 20012-00001 band have been recorded with high precision and fidelity. As a result of a refined spectral analysis, based on the implementation of the modified Hartmann-Tran profile, line center frequencies, pressure broadening and pressure shifting coefficients have been determined. Finally, we demonstrate the measurement of CO2 mole fractions with a subpromille statistical uncertainty

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Muhammad Asad Khan, Vittorio D'Agostino, Stefania Gravina, Livio Gianfrani, Antonio Castrillo. 2026-02-27. Comb-locked cavity ring-down spectroscopy of CO2 at 2-micron wavelength. https://arxiv.org/abs/2602.23812

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