Abstract A low-frequency photoacoustic (PA) sensor based on Parylene-C diaphragm for space-limited trace gas detection is presented. The overall structure of the sensor head includes a cylindrical brass shell, a Parylene-C diaphragm, and a PA cavity regarded as the Fabry-Perot (F-P) cavity as well. The volume of the PA cavity is only 74 μL. A distributed feedback (DFB) laser is used as an acoustic excitation source. The deflection of the Parylene-C diaphragm was measured by using fiber-optic white-light interference (WLI) method to obtain the PA pressure signal. The PA sensor is used for acetylene (C2H2) detection with a detection limit of 88.4 parts-per-billion (ppb) when the lock-in integration time is 1 s.

中文翻译：

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用于空间受限痕量气体检测的基于 Parylene-C 隔膜的低频光声传感器

摘要 提出了一种基于 Parylene-C 膜片的低频光声 (PA) 传感器，用于空间受限的痕量气体检测。传感器头的整体结构包括一个圆柱形黄铜外壳、一个 Parylene-C 膜片和一个 PA 腔，也被认为是 Fabry-Perot (FP) 腔。PA 腔的体积仅为 74 μL。分布式反馈 (DFB) 激光器用作声学激发源。Parylene-C 膜片的偏转是通过使用光纤白光干涉 (WLI) 方法来测量的，以获得 PA 压力信号。PA 传感器用于乙炔 (C2H2) 检测，当锁定积分时间为 1 秒时，检测限为 88.4 ppb。