Optical feedback noise-immune cavity-enhanced optical heterodyne molecular spectrometry for sub-Doppler-broadened detection of C 2 H 2

作者：Xiaobin Zhou, Gang Zhao, Yong Li, Ziwei Cheng, Kang Jiao, Bofeng Zhang, Zihao Zhang, Yanke Li, Xiaojuan Yan, Weiguang Ma, Suotang Jia · 发表于：Optics Letters · 年份：2023 · DOI：10.1364/ol.507004 · 被引用次数：9 · 研究领域：Spectroscopy and Laser Applications、Atmospheric Ozone and Climate、Laser Design and Applications

A novel, to the best of our knowledge, noise-immune cavity-enhanced optical heterodyne molecular spectrometry (NICE-OHMS) has been developed, utilizing optical feedback for laser-to-cavity locking with a common distributed-feedback diode laser. The system incorporates active control of the feedback phase and feedforward control of the laser current, allowing for consecutive laser frequency detuning by scanning a piezoelectric transducer (PZT) attached to the cavity. To enhance the fidelity of the spectroscopic signal, wavelength-modulated (wm) NICE-OHMS is implemented. Benefiting from the optical feedback, a modulation frequency of 15 kHz is achieved, surpassing the frequencies typically used in traditional NICE-OHMS setups. Then, the sub-Doppler-broadened wm-NICE-OHMS signal of acetylene at 1.53 µm is observed. A seven-fold improvement in signal to noise ratio has been demonstrated compared to NICE-OHMS alone and a limit of detection of 6.1 × 10 −10 cm −1 is achieved.