Zhang Bo, Jia Yunjiang, Zhao Benlei, Zhu Xiaosong, Shi Yiwei
Opt Lett. 2023 Aug 15;48(16):4201-4204. doi: 10.1364/OL.497052.
In this work, a photoacoustic (PA) gas sensor with a micro-embedded acoustic resonator for gas leakage detection was demonstrated. The micro-embedded acoustic resonator was fabricated by putting a leaky hollow-core fiber (L-HCF) into a cylindrical buffer chamber. The L-HCF was utilized as the PA cavity and the light transmission media simultaneously. The optimal inner diameter of the L-HCF was 1.7 mm. The embedded acoustic resonator was experimentally proven to be equivalent to a T-type half-open acoustic resonator, but the structure became much more compact. The volume of the amount of gas in the cell was only ∼0.3 mL, and the gas diffusion time to fill the sensor under room temperature (25°C) and ambient pressure (101 kPa) was ∼44 s. Trace acetylene (CH) in pure nitrogen (N) was chosen as the target gas, and the minimum detectable limit (MDL) reached 29 ppb when the lock-in integration time was 1 s. The normalized noise equivalent absorption (NNEA) coefficient was calculated to be 3.0 × 10 W·cm·Hz. The micro-resonant PA gas sensor, with merits of compactness, low gas consumption, and low cost, has the potential to be a remote gas sensing scheme in fields of environmental protection, industrial process monitoring, and so on.
在这项工作中，展示了一种带有微嵌入式声学谐振器的光声（PA）气体传感器，用于气体泄漏检测。通过将泄漏型空心光纤（L-HCF）放入圆柱形缓冲腔中来制造微嵌入式声学谐振器。L-HCF 同时用作 PA 腔和光传输介质。L-HCF 的最佳内径为 1.7 毫米。实验证明，嵌入式声学谐振器等效于 T 型半开放式声学谐振器，但结构变得更加紧凑。传感器单元内气体的体积仅约为 0.3 mL，在室温（25°C）和环境压力（101 kPa）下填充传感器的气体扩散时间约为 44 秒。选择纯氮气（N₂）中的痕量乙炔（C₂H₂）作为目标气体，当锁相积分时间为 1 秒时，最低检测限（MDL）达到 29 ppb。计算得到归一化噪声等效吸收（NNEA）系数为 3.0×10⁻⁹ W·cm·Hz。这种微谐振 PA 气体传感器具有紧凑、低气体消耗和低成本的优点，有潜力成为环境保护、工业过程监测等领域的远程气体传感方案。
