Signal correction using transmitted spot information: A low error photoacoustic spectroscopy-based gas detection system

Photoacoustic spectroscopy (PAS)-based gas sensing system is popular in industries due to advantages of high sensitivity and portable. However, data fluctuation often occurs in the on-line monitoring mode, and the reason has not been found yet. In this work, influential factors and environment-related variables of the photoacoustic (PA) signal were analyzed. A beam quality analyzer was employed as a tool to detect the parameters of the optical path condition. The robustness was verified by a long-time measurement. The results showed that the centroid y of the beam spot has the best linear correlation with the PA signal with a correlation coefficient higher than 0.9. The largest and average measurement error were 26.98 % and 10.95 % without the correction, while after the correction they were only 12.24 % and 5.39 %. The results can provide ideas to the robustness improvement of the PAS gas detection system.