Open AccessAcetylene sensing system based on wavelength modulation spectroscopy using a triple-row circular multi-pass cell
Author(s) -
Ming-Li Zou,
Zheng Yang,
Liqun Sun,
Xianshun Ming
Publication year - 2020
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.388343
Subject(s) - optics , materials science , modulation (music) , sensitivity (control systems) , spectroscopy , wavelength , absorption (acoustics) , allan variance , tunable diode laser absorption spectroscopy , trace gas , absorption spectroscopy , acetylene , laser , tunable laser , standard deviation , optoelectronics , physics , chemistry , acoustics , electronic engineering , mathematics , statistics , quantum mechanics , engineering , organic chemistry , meteorology
A sensitive acetylene (C 2 H 2 ) sensing system based on a novel triple-row circular multi-pass cell (CMPC) was demonstrated. This CMPC has an effective optical length of 21.9 m within an extremely small volume of 100.1 mL. We utilized wavelength modulation spectroscopy (WMS) for absorption spectroscopy detection of C 2 H 2 . The distance between the two minima of the second harmonic was used to normalize the maximum value of it, which makes the time to obtain stable output for continuous detection shorten dramatically. A fiber-coupled distributed feedback (DFB) diode laser emitting at 1.5316 µm was employed as a light source. An Allan deviation analysis yielded a detection sensitivity of 76.75 ppb with a normalized noise equivalent absorption coefficient of 8.8 × 10 -10 cm -1 Hz -1/2 during an average time of 340 s. With a fast stable time, reduced size and high detection sensitivity, the proposed sensing system is suitable for trace gas sensing in a weight-limited unmanned aerial vehicle (UAV) and an exhalation diagnosis for smoking test.