Li Chenxi, Han Xiao, Guo Min, Qi Hongchao, Wang Heng, Zhao Xinyu, Chen Ke
School of Optoelectronic Engineering and Instrumentation Science, Dalian University of Technology, Dalian, Liaoning 116024, China.
Zhejiang Engineering Research Center of MEMS, Shaoxing University, Shaoxing, Zhejiang 312000, China.
Anal Chem. 2024 Jun 11;96(23):9438-9446. doi: 10.1021/acs.analchem.4c00532. Epub 2024 May 28.
A high-sensitivity fiber-optic photoacoustic (PA) gas microsensor is demonstrated with dual enhancement based on acoustics and detection. Due to the characteristic of small size, a Helmholtz resonator is integrated into a miniature PA sensor. The acoustically amplified PA signal is detected by a high-sensitivity fiber Fabry-Perot (F-P) interferometric cantilever. The first-order resonant frequencies of the interferometric cantilever and Helmholtz resonator are matched by subtle adjustments. The weak PA signal is significantly enhanced in a volume of only 0.35 mL, which breaks the volume limitation of the resonance modes in traditional PA sensing systems. To improve the resolution of the microsensor, a white light interferometry (WLI)-based spectral demodulation algorithm is utilized. The experimental results indicate that the minimum detection limit of acetylene (CH) drops to about 15 ppb with an averaging time of 100 s, corresponding to the normalized noise equivalent absorption (NNEA) coefficient of 2.7 × 10 W·cm·Hz. The dual resonance enhanced fiber-optic PA gas microsensor has the merits of high sensitivity, intrinsic safety, and compact structure.
展示了一种基于声学和检测双重增强的高灵敏度光纤光声（PA）气体微传感器。由于尺寸小的特点，将亥姆霍兹谐振器集成到微型PA传感器中。通过高灵敏度光纤法布里 - 珀罗（F - P）干涉悬臂检测经声学放大的PA信号。通过精细调整使干涉悬臂和亥姆霍兹谐振器的一阶谐振频率匹配。在仅0.35 mL的体积内，微弱的PA信号得到显著增强，这突破了传统PA传感系统中共振模式的体积限制。为了提高微传感器的分辨率，采用了基于白光干涉测量（WLI）的光谱解调算法。实验结果表明，乙炔（CH）的最低检测限降至约15 ppb，平均时间为100 s，对应归一化噪声等效吸收（NNEA）系数为2.7×10 W·cm·Hz。这种双共振增强光纤光声气体微传感器具有高灵敏度、本质安全和结构紧凑的优点。
