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High sensitivity open‐path gas sensor based on a triangular multi‐pass cell
Author(s) -
Wu Xu,
Sang Jian,
Zhou Sheng,
Li Jingsong
Publication year - 2021
Publication title -
microwave and optical technology letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.304
H-Index - 76
eISSN - 1098-2760
pISSN - 0895-2477
DOI - 10.1002/mop.32949
Subject(s) - trace gas , detection limit , sensitivity (control systems) , allan variance , atmospheric pressure , laser , sampling (signal processing) , diode , analytical chemistry (journal) , optics , materials science , physics , electronic engineering , chemistry , optoelectronics , engineering , filter (signal processing) , electrical engineering , mathematics , statistics , chromatography , standard deviation , meteorology
In this article, a gas sensing technique utilizing a compact multi‐pass absorption cell in a triangular configuration was proposed for open‐path trace gases detection. To demonstrate this technique, an open‐path gas sensor system was developed by combing the innovated triangular multi‐pass cell with a near infrared distributed feedback diode laser (at 1.65 μm) for simultaneous detection of atmospheric CH 4 and H 2 O. A Gaussian‐noise‐limited limit of detection of approximate 52 ppb and 445 ppm were achieved for CH 4 and H 2 O, respectively, with 1 Hz sampling rate and at normal atmospheric pressure. Allan variance analysis indicates that a sensitivity of 5.5 ppb (for CH 4 ) and 75 ppm (for H 2 O) could be obtained at the optimal averaging time of 300 s, which is comparative with the mid‐infrared laser based gas sensors. This technique will be a critical tool for developing low‐cost open‐path trace gas monitoring networks for environmental, industrial, and public security applications.