Techniques to enhance the photoacoustic signal for trace gas sensing: A review

• Published in: Sensors and actuators. A. Physical. Vol. 345; p. 113807
• Main Authors: Wang, Fupeng, Cheng, Yaopeng, Xue, Qingsheng, Wang, Qiang, Liang, Rui, Wu, Jinghua, Sun, Jiachen, Zhu, Cunguang, Li, Qian
• Format: Journal Article
• Language: English
• Published: Lausanne Elsevier B.V 01.10.2022; Elsevier BV
• Subjects: Acoustic absorption; Acoustic waves; Cantilever; Custom tuning fork; EDFA; Fiber optics; Fiber-optic microphone; Gas detectors; Gas sensors; Optical communication; Photoacoustic enhancement; Photoacoustic spectroscopy; Resonator; Surface acoustic waves; Trace gases; Transducers; CRDS; Resonator; PAS; EDFL; FLI-PAS; FBG; PZT; Photoacoustic spectroscopy; Cantilever; CEPAS; TDLAS; ASE; Photoacoustic enhancement; MDL; SNR; EC-PAS; QEPAS; IC-PAS; Fiber-optic microphone; EDFA; Custom tuning fork; NDIR; WMS; RAM
• ISSN: 0924-4247; 1873-3069
• DOI: 10.1016/j.sna.2022.113807

Photoacoustic spectroscopy (PAS), which relies on the detection of absorption-induced acoustic waves, is widely used for gas sensing. This paper summarizes and discusses most of the recent techniques for photoacoustic enhancement throughout the overall process from laser-molecule interaction to acoustic wave detection. Considering the theoretical principle and system composition of PAS gas sensor, we classify photoacoustic enhancing techniques into three aspects. The first one is to enhance the photoacoustic excitation by building up the laser power in terms of the positive proportional relation between the optical power and photoacoustic signal. The second one is to amplify the acoustic strength with various kinds of resonators after the photoacoustic generation. The third approach to further improve the photoacoustic detection is to develop more efficient acoustic transducers, for example, custom tuning fork, cantilever and fiber-optic microphone. Finally, the advantages and limitations of these different techniques are analyzed. [Display omitted]