AUTHOR=Wang Cheng , Wang Zongliang , Pang Xiyu 

TITLE=Quartz-Enhanced Photoacoustic Spectroscopy for Four-Component Gas Detection Based on Two Off-Beam Acoustic Microresonators

JOURNAL=Frontiers in Physics

VOLUME=8

YEAR=2020

URL=https://www.frontiersin.org/journals/physics/articles/10.3389/fphy.2020.594326

DOI=10.3389/fphy.2020.594326

ISSN=2296-424X

ABSTRACT=<p>A compact and portable quartz-enhanced photoacoustic spectroscopy gas sensor was developed for four-component gas detection using two off-beam acoustic microresonators The two AMRs were placed in parallel on opposing sides of a quartz tuning fork for photoacoustic signal enhancement. Four distributed feedback (DFB) lasers were connected to the four ends of the two off-beam AMRs using a fiber collimator for photoacoustic signal excitation. Four-component gas sensing was achieved via time-division multiplexing of the distributed feedback laser driver currents. The four-component gas sensing scheme was used to detect acetylene (C<sub>2</sub>H<sub>2</sub>) at 1,532.83 nm, methane (CH<sub>4</sub>) at 1,653.722 nm, water vapor (H<sub>2</sub>O) at 1,368.597 nm and carbon dioxide (CO<sub>2</sub>) at 1,577.787 nm for feasibility testing. Minimum detection limits of 3.6 ppmv for C<sub>2</sub>H<sub>2</sub>, 34.71 ppmv for CH<sub>4</sub>, 1.09 ppmv for H<sub>2</sub>O, and 341.18 ppmv for CO<sub>2</sub> were obtained, and the linear responses reached 0.9982, 0.9969, 0.99843 and 0.99591 for C<sub>2</sub>H<sub>2</sub>, CH<sub>4</sub>, H<sub>2</sub>O and CO<sub>2</sub>, respectively, at 1.5 s intervals.</p>