High-Sensitivity Narrow-band T-Shaped Cantilever Fabry-Perot Acoustic Sensor for Photoacoustic Spectroscopy

Jilong Wang, Qiaoyun Wang*, Chongyue Yan, Shunyuan Xu, Xin Zou, Qiang Wu, Wai Pang Ng, Richard Binns, Yongqing Fu

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review


Photoacoustic spectroscopy (PAS) has been rapidly developed and applied to different detection scenarios. The acoustic pressure detection is an important part in the PAS system. In this paper, an ultrahigh sensitivity Fabry-Perot acoustic sensor with a T-shaped cantilever was proposed. To achieve the best acoustic pressure effect, the dimension of the cantilever structure was designed and optimized by finite element analysis using COMSOL Multiphysics. Simulation results showed that the sensitivity of such T-shaped cantilever was 1.5 times higher than that based on a rectangular cantilever, and the resonance frequency of T-shaped cantilever were able to modulate from 800 Hz to 1500 Hz by adjusting the multi-parameter characteristics. Experimental sensing results showed that the resonance frequency of T-shaped Fabry-Perot acoustic sensor was 1080 Hz, yielding a high sensitivity of 1.428 μm/Pa, with a signal-to-noise ratio (SNR) of 84.8 dB and a detectable pressure limit of 1.9 μPa/Hz1/2@1 kHz. We successfully used such acoustic sensor to measure acetylene (C2H2) concentration in the PAS. The sensitivity of PAS for C2H2 gas was 3.22 pm/ppm with a concentration range of 50 ppm ∼100 ppm, and the minimum detection limit was 24.91ppb.
Original languageEnglish
Article number100626
Pages (from-to)1-12
Number of pages12
Early online date8 Jun 2024
Publication statusE-pub ahead of print - 8 Jun 2024

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