Pan Yufeng, Fu Lujun, Zhang Jiangshan, Lu Ping
Wuhan National Laboratory for Optoelectronics (WNLO) and National Engineering Research Center of Next Generation Internet Access-system, School of Optical and Electronic Information, Huazhong University of Science and Technology, Wuhan 430074, China.
Optics Valley Laboratory, Wuhan 430074, China.
Photoacoustics. 2024 Aug 5;39:100639. doi: 10.1016/j.pacs.2024.100639. eCollection 2024 Oct.
A proof-of-concept on-beam tuning-fork-enhanced photoacoustic sensor based on an open-closed single-tube acoustic-microresonator (AmR) was proposed and investigated for the first time, to the best of our knowledge. Due to the high acoustic amplification effect, the open-closed AmR improved the detection sensitivity by 54 times with respect to the bare tuning fork (TF). Compared to traditional dual-tube/single-tube on-beam spectrophone configuration, the developed approach significantly facilitates the laser beam alignment and reduces the sensor size and gas consumption. A 6.6 kHz low-frequency custom aluminum alloy TF was employed as the acoustic transducer to detect the photoacoustic signal. The vibration of TF was measured by a fiber-optic Fabry-Pérot (FP) interferometer (FPI). The modulation depth, tube length and laser power were experimentally optimized and evaluated in detail. An acetylene (CH) 1σ minimum detection limit (MDL) of 6.3 ppb was obtained with a high laser power of ∼ 500 mW, corresponding to a normalized noise equivalent absorption (NNEA) coefficient of 6.5 × 10 cm W/Hz. The compact spectrophone size and all-fiber measurement method can make the PAS-based sensor have great application prospects in dissolved gases detection in transformer oil, remote gas detection, space-limited gas detection, and etc.
据我们所知，首次提出并研究了一种基于开闭单管声微谐振器（AmR）的概念验证型光束调谐叉增强光声传感器。由于高声放大效应，开闭式AmR相对于裸调谐叉（TF）将检测灵敏度提高了54倍。与传统的双管/单管光束分光电话配置相比，所开发的方法显著便于激光束对准，并减小了传感器尺寸和气体消耗。采用一个6.6kHz的低频定制铝合金TF作为声换能器来检测光声信号。通过光纤法布里-珀罗（FP）干涉仪（FPI）测量TF的振动。对调制深度、管长和激光功率进行了实验优化并详细评估。在约500mW的高激光功率下，获得了乙炔（CH）1σ最低检测限（MDL）为6.3ppb，对应归一化噪声等效吸收（NNEA）系数为6.5×10 cm W/Hz。紧凑的分光电话尺寸和全光纤测量方法可使基于光声光谱的传感器在变压器油中溶解气体检测、远程气体检测、空间受限气体检测等方面具有广阔的应用前景。
