Open AccessLight-induced off-axis cavity-enhanced thermoelastic spectroscopy in the near-infrared for trace gas sensing
Author(s) -
Kaiyuan Zheng,
Chuantao Zheng,
Lien Hu,
Gangyun Guan,
Y. Zee,
Fang Song,
Yu Zhang,
Yiding Wang,
Frank K. Tittel
Publication year - 2021
Publication title -
optics express
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.394
H-Index - 271
ISSN - 1094-4087
DOI - 10.1364/oe.430745
Subject(s) - finesse , optics , trace gas , spectroscopy , materials science , cavity ring down spectroscopy , infrared , fabry–pérot interferometer , detection limit , optical path , absorption spectroscopy , optoelectronics , physics , chemistry , wavelength , chromatography , quantum mechanics , meteorology
A trace gas sensing technique of light-induced off-axis cavity-enhanced thermoelastic spectroscopy (OA-CETES) in the near-infrared was demonstrated by combing a high-finesse off-axis integrated cavity and a high Q-factor resonant quartz tuning fork (QTF). Sensor parameters of the cavity and QTF were optimized numerically and experimentally. As a proof-of-principle, we employed the OA-CETES for water vapor (H 2 O) detection using a QTF (Q-factor ∼12000 in atmospheric pressure) and a 10cm-long Fabry-Perot cavity (finesse ∼ 482). By probing a H 2 O line at 7306.75 cm -1 , the developed OA-CETES sensor achieved a minimum detection limit (MDL) of 8.7 parts per million (ppm) for a 300 ms integration time and a normalized noise equivalent absorption (NNEA) coefficient of 4.12 × 10 -9 cm -1 WHz -1/2 . Continuous monitoring of indoor and outdoor atmospheric H 2 O concentration levels was performed for verifying the sensing applicability. The realization of the proposed OA-CETES technique with compact QTF and long effective path cavity allows a class of optical sensors with low cost, high sensitivity and potential for long-distance and multi-point sensing.