Zhang Bo, Shi Yiwei
Opt Express. 2023 Oct 9;31(21):34708-34720. doi: 10.1364/OE.500212.
Here we designed, optimized, and proposed a flexible low frequency resonant photoacoustic (PA) gas sensor by using a large core leaky hollow core fiber (L-HCF). The influences from the dimensions, the transmission loss and the bending loss on the performance of the flexible PA gas sensor were systematically investigated. In this work, the optimized inner diameter and length of the L-HCF were 1.7 mm and 300 mm, respectively. The L-HCF based PA cell constant was calculated to be 12115 Pa/(W·cm). The minimum detectable limit (MDL) for trace CH detection achieved 23.0 ppb when the lock-in integration time was 200 s by using a near-infrared distributed feedback (DFB) laser source and a low-cost electrical micro-electro-mechanical system (MEMS) microphone. Besides, the amplitude decay ratio of the of the PA signal was only 11.3% when the bending radius of the L-HCF was 100 mm. The normalized noise equivalent absorption (NNEA) coefficient is calculated to be 6.6 × 10 W•cm•Hz. The L-HCF based PA cell was proved to own merits of compact size, high cell constant, small gas volume and low cost.
在此，我们设计、优化并提出了一种采用大芯径泄漏空心光纤（L-HCF）的柔性低频共振光声（PA）气体传感器。系统研究了尺寸、传输损耗和弯曲损耗对柔性PA气体传感器性能的影响。在这项工作中，L-HCF的优化内径和长度分别为1.7毫米和300毫米。基于L-HCF的PA池常数经计算为12115 Pa/(W·cm)。当使用近红外分布反馈（DFB）激光源和低成本的微机电系统（MEMS）麦克风且锁定积分时间为200秒时，痕量CH检测的最低检测限（MDL）达到23.0 ppb。此外，当L-HCF的弯曲半径为100毫米时，PA信号的幅度衰减率仅为11.3%。归一化噪声等效吸收（NNEA）系数经计算为6.6×10 W•cm•Hz。基于L-HCF的PA池被证明具有尺寸紧凑、池常数高、气体体积小和成本低的优点。
