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arXiv · 2505.23418

Cavity ringdown spectroscopy at 2 ${\mu}$m wavelength assisted by a comb-locked optical parametric oscillator

Vittorio D'Agostino·Eugenio Fasci·Muhammad Asad Khan·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 molecular spectroscopy at 2 ${\mu}$m. It is based on the use of an external-cavity diode laser that is offset-frequency locked to the signal output of a singly-resonant optical parametric oscillator. This latter acts as reference laser, being locked to a self-referenced optical frequency comb, which in turn is stabilized against a GPS-disciplined Rb-clock. The performance of the spectrometer is investigated by probing a pair of N$_2$O transitions belonging to hot vibrational bands. One of these, never observed before, is included in the N$_2$O line list of the ExoMol database. Absolute center frequencies are retrieved with a 1-${\sigma}$ global uncertainty of 108 kHz.

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Vittorio D'Agostino, Eugenio Fasci, Muhammad Asad Khan, Stefania Gravina, Livio Gianfrani, Antonio Castrillo. 2025-05-29. Cavity ringdown spectroscopy at 2 ${\mu}$m wavelength assisted by a comb-locked optical parametric oscillator. https://arxiv.org/abs/2505.23418

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