National Key Laboratory of Science and Technology on Tunable Laser, Harbin Institute of Technology, Harbin 150001, China.
Sensors (Basel). 2022 Jul 6;22(14):5087. doi: 10.3390/s22145087.
Oxygen (O) is a colorless and odorless substance, and is the most important gas in human life and industrial production. In this invited paper, a highly sensitive O sensor based on reflector-enhanced photoacoustic spectroscopy (PAS) is reported for the first time. A diode laser emitting at 760 nm was used as the excitation source. The diode laser beam was reflected by the adopted reflector to pass thorough the photoacoustic cell twice and further increase the optical absorption. With such enhanced absorption strategy, compared with the PAS system without the reflector, the reflector-enhanced O-PAS sensor system had 1.85 times the signal improvement. The minimum detection limit (MDL) of such a reflector-enhanced O-PAS sensor was experimentally determined to be 0.54%. The concentration response of this sensor was investigated when O with a different concentration was used. The obtained results showed it has an excellent linear concentration response. The system stability was analyzed by using Allan variance, which indicated that the MDL for such a reflector-enhanced O-PAS sensor could be improved to 318 ppm when the integration time of this sensor system is 1560 s. Finally, the O concentration on the outside was continuously monitored for 24 h, indicated that this reflector-enhanced O-PAS sensor system has an excellent measurement ability for actual applications in environmental monitoring, medical diagnostics, and other fields.
氧气（O）是一种无色无味的物质，是人类生命和工业生产中最重要的气体。在这篇特邀论文中，首次报道了一种基于反射增强光声光谱（PAS）的高灵敏度 O 传感器。采用的二极管激光器在 760nm 处发射，作为激发源。二极管激光束被采用的反射镜反射，通过光声池两次，进一步增加光吸收。通过这种增强吸收策略，与没有反射镜的 PAS 系统相比，反射增强 O-PAS 传感器系统的信号提高了 1.85 倍。通过实验确定了这种反射增强 O-PAS 传感器的最小检测限（MDL）为 0.54%。当使用不同浓度的 O 时，研究了这种传感器的浓度响应。获得的结果表明，它具有出色的线性浓度响应。通过 Allan 方差分析了系统稳定性，表明当传感器系统的积分时间为 1560s 时，这种反射增强 O-PAS 传感器的 MDL 可以提高到 318ppm。最后，连续监测了 24 小时外部的 O 浓度，表明这种反射增强 O-PAS 传感器系统具有出色的测量能力，可用于环境监测、医疗诊断和其他领域的实际应用。
