Liu Yihua, Lin Haoyang, Montano Baiyang Antonio Zhou, Zhu Wenguo, Zhong Yongchun, Kan Ruifeng, Yuan Bin, Yu Jianhui, Shao Min, Zheng Huadan
Guangdong Provincial Key Laboratory of Optical Fiber Sensing and Communications, and Department of Optoelectronic Engineering, Jinan University, Guangzhou 510632, China.
Key Laboratory of Environmental Optics and Technology, Anhui Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Hefei 230031, China.
Photoacoustics. 2022 Jan 27;25:100332. doi: 10.1016/j.pacs.2022.100332. eCollection 2022 Mar.
In this paper, a highly sensitive and integrated near-infrared CO sensor was developed based on quartz-enhanced photoacoustic spectroscopy (QEPAS). Unlike traditional QEPAS, a novel pilot line manufactured quartz tuning fork (QTF) with a resonance frequency of 28 kHz was employed as an acoustic wave transducer. A near-infrared DFB laser diode emitting at 2004 nm was employed as the excitation light source for CO detection. An integrated near-infrared QEPAS module was designed and manufactured. The QTF, acoustic micro resonator (AmR), gas cell, and laser fiber are integrated, resulting in a super compact acoustic detection module (ADM). Compared to a traditional 32 kHz QTF, the QEPAS signal amplitude increased by > 2 times by the integrated QEPAS module based on a 28 kHz QTF. At atmospheric pressure, a 5.4 ppm detection limit at a CO absorption line of 4991.25 cm was achieved with an integration time of 1 s. The long-term performance and stability of the CO sensor system were investigated using Allan variance analysis. Finally, the minimum detection limit (MDL) was improved to 0.7 ppm when the integration time was 125 s. A portable CO sensor system based on QEPAS was developed for 24 h continuous monitoring of CO in the greenhouse located in Guangzhou city. The CO concentration variations were clearly observed during day and night. Photosynthesis and respiration plants can be further researched by the portable CO sensor system.
本文基于石英增强光声光谱技术（QEPAS）开发了一种高灵敏度集成近红外一氧化碳（CO）传感器。与传统的QEPAS不同，采用了一种新型中试生产线制造的共振频率为28kHz的石英音叉（QTF）作为声波换能器。使用发射波长为2004nm的近红外分布反馈（DFB）激光二极管作为检测CO的激发光源。设计并制造了一个集成近红外QEPAS模块。该模块将QTF、声学微谐振器（AmR）、气室和激光光纤集成在一起，形成了一个超紧凑的声学检测模块（ADM）。与传统的32kHz QTF相比，基于28kHz QTF的集成QEPAS模块使QEPAS信号幅度增加了2倍以上。在大气压下，积分时间为1s时，在4991.25cm-1的CO吸收线处实现了5.4ppm的检测限。利用阿伦方差分析研究了CO传感器系统的长期性能和稳定性。最后，当积分时间为125s时，最低检测限（MDL）提高到了0.7ppm。开发了一种基于QEPAS的便携式CO传感器系统，用于对广州市某温室中的CO进行24小时连续监测。清晰观察到了温室中CO浓度在白天和夜晚的变化情况。该便携式CO传感器系统可用于进一步研究植物的光合作用和呼吸作用。
