Zhang Chu, He Ying, Qiao Shunda, Liu Yahui, Ma Yufei
National Key Laboratory of Laser Spatial Information, Harbin Institute of Technology, Harbin 150001, China.
Photoacoustics. 2024 Jul 9;38:100634. doi: 10.1016/j.pacs.2024.100634. eCollection 2024 Aug.
A high-sensitivity photoacoustic spectroscopy (PAS) sensor based on differential Helmholtz photoacoustic cell (DHPAC) with dense spot pattern is reported in this paper for the first time. A multi-pass cell based on two concave mirrors was designed to achieve a dense spot pattern, which realized 212 times excitation of incident laser. A finite element analysis was utilized to simulate the sound field distribution and frequency response of the designed DHPAC. An erbium-doped fiber amplifier (EDFA) was employed to amplify the output optical power of the laser to achieve strong excitation. In order to assess the designed sensor's performance, an acetylene (CH) detection system was established using a near infrared diode laser with a central wavelength 1530.3 nm. According to experimental results, the differential characteristics of DHPAC was verified. Compared to the sensor without dense spot pattern, the photoacoustic signal with dense spot pattern had a 44.73 times improvement. The minimum detection limit (MDL) of the designed CH-PAS sensor can be improved to 5 ppb when the average time of the sensor system is 200 s.
本文首次报道了一种基于具有密集光斑图案的差分亥姆霍兹光声池（DHPAC）的高灵敏度光声光谱（PAS）传感器。设计了一种基于两个凹面镜的多程池以实现密集光斑图案，该图案实现了对入射激光212倍的激发。利用有限元分析来模拟所设计的DHPAC的声场分布和频率响应。采用掺铒光纤放大器（EDFA）来放大激光的输出光功率以实现强激发。为了评估所设计传感器的性能，使用中心波长为1530.3 nm的近红外二极管激光器建立了乙炔（CH）检测系统。根据实验结果，验证了DHPAC的差分特性。与没有密集光斑图案的传感器相比，具有密集光斑图案的光声信号提高了44.73倍。当传感器系统的平均时间为200 s时，所设计的CH-PAS传感器的最低检测限（MDL）可提高到5 ppb。
