Fan Enbo, Liu Haojie, Wang Chao, Ma Jun, Guan Bai-Ou
Guangdong Provincial Key Laboratory of Optical Fiber Sensing and Communications, Institute of Photonics Technology, Jinan University, Guangzhou 511443, China.
The Center for Smart Sensing System, Julong College, Shenzhen Technology University, Shenzhen 518118, China.
Photoacoustics. 2023 Jun 20;32:100524. doi: 10.1016/j.pacs.2023.100524. eCollection 2023 Aug.
Optical fiber acoustic sensors with miniature size and high sensitivity are attractive to develop compact photoacoustic spectroscopy. Here, a compact photoacoustic gas sensor was demonstrated by utilizing a diaphragm-based fiber-optic Fabry-Perot cavity as both the acoustic sensor and the multipass cell. A nanoscale graphite film was used as the flexible diaphragm to increase the acoustic sensitivity of the Fabry-Perot cavity and the cavity inner surface was coated with highly-reflective Au film to form a multipass cell for amplification of the photoacoustic signal. With a laser power of 20 mW at 1532.8 nm, the sensor demonstrated a low detection limit of ∼ 50 ppb for CH gas with an integration time of ∼ 100 s. The optical fiber photoacoustic gas sensor with a millimeter-scale diameter and ppb-level detection limit is promising for trace gas sensing in various areas including industrial process and environmental monitoring.
尺寸小巧且灵敏度高的光纤声学传感器对于开发紧凑型光声光谱技术具有吸引力。在此，通过利用基于隔膜的光纤法布里-珀罗腔作为声学传感器和多程池，展示了一种紧凑型光声气体传感器。使用纳米级石墨膜作为柔性隔膜以提高法布里-珀罗腔的声学灵敏度，并且在腔体内表面涂覆高反射率的金膜以形成用于放大光声信号的多程池。在1532.8nm波长处激光功率为20mW的情况下，该传感器在积分时间约为100s时对CH气体表现出约50ppb的低检测限。这种直径为毫米级且检测限达到ppb级的光纤光声气体传感器在包括工业过程和环境监测在内的各个领域的痕量气体传感方面具有广阔前景。
