Sun Bo, Wei Tingting, Zhang Mingjiang, Qiao Lijun, Ma Zhe, Sampaolo Angelo, Patimisco Pietro, Spagnolo Vincenzo, Wu Hongpeng, Dong Lei
College of Physics and Optoelectronics, Taiyuan University of Technology, Taiyuan 030024, China.
Shanxi Key Laboratory of Precision Measurement Physics, Taiyuan University of Technology, Taiyuan 030024, China.
Photoacoustics. 2025 Feb 27;43:100708. doi: 10.1016/j.pacs.2025.100708. eCollection 2025 Jun.
We present a novel optical synchronized signal demodulation (OSSD) method applied in quartz-enhanced photoacoustic spectroscopy (QEPAS) for remote gas sensing. Using 1 % of the laser source as an optical synchronization signal, kilometer-scale remote gas detection was achieved, overcoming the challenges of long-distance real-time detection in complex environments with conventional QEPAS. A time-sharing OSSD-QEPAS system for sewer methane detection was subsequently developed. The system's modulation depth was optimized, and the catalytic effect of water vapor on photoacoustic signals was validated, resulting in a CH₄ sensor achieving a detection limit of 445 ppb with a 300-ms averaging time, and an excellent linear dynamic range with a R = 0.999. To demonstrate the stability, robustness, and accuracy of the OSSD-QEPAS system, continuous methane measurements covering a 14-hour period at two different sewer locations on campus were performed.
我们提出了一种应用于石英增强光声光谱（QEPAS）的新型光学同步信号解调（OSSD）方法，用于远程气体传感。使用1%的激光源作为光学同步信号，实现了千米级的远程气体检测，克服了传统QEPAS在复杂环境中进行长距离实时检测的挑战。随后开发了一种用于下水道甲烷检测的分时OSSD-QEPAS系统。对该系统的调制深度进行了优化，并验证了水蒸气对光声信号的催化作用，结果表明，甲烷传感器在300毫秒平均时间下的检测限达到445 ppb，并且具有R = 0.999的出色线性动态范围。为了证明OSSD-QEPAS系统的稳定性、鲁棒性和准确性，在校园内两个不同的下水道位置进行了为期14小时的连续甲烷测量。
