Opt Express. 2023 Apr 24;31(9):14851-14861. doi: 10.1364/OE.488835.
A near-infrared (NIR) sub-ppm level photoacoustic sensor for hydrogen sulfide (HS) using a differential Helmholtz resonator (DHR) as the photoacoustic cell (PAC) was presented. The core detection system was composed of a NIR diode laser with a center wavelength of 1578.13 nm, an Erbium-doped optical fiber amplifier (EDFA) with an output power of ∼120 mW, and a DHR. Finite element simulation software was used to analyze the influence of the DHR parameters on the resonant frequency and acoustic pressure distribution of the system. Through simulation and comparison, the volume of the DHR was 1/16 that of the conventional H-type PAC for a similar resonant frequency. The performance of the photoacoustic sensor was evaluated after optimizing the DHR structure and modulation frequency. The experimental results showed that the sensor had an excellent linear response to the gas concentration and the minimum detection limit (MDL) for HS detection in differential mode can reach 460.8 ppb.
提出了一种基于差分亥姆霍兹共振器（DHR）作为光声池（PAC）的近红外（NIR）亚ppm 级硫化氢（HS）光声传感器。核心检测系统由中心波长为 1578.13nm 的 NIR 二极管激光器、输出功率约为 120mW 的掺铒光纤放大器（EDFA）和 DHR 组成。有限元仿真软件用于分析 DHR 参数对系统谐振频率和声波压力分布的影响。通过仿真和比较，DHR 的体积为传统 H 型 PAC 的 1/16，而谐振频率相似。优化 DHR 结构和调制频率后，对光声传感器的性能进行了评估。实验结果表明，该传感器对气体浓度具有优异的线性响应，差分模式下 HS 的最小检测限（MDL）可达 460.8ppb。
