PolySense Lab, Dipartimento Interateneo di Fisica, University and Politecnico of Bari, CNR-IFN, Via Amendola 173, 70126 Bari, Italy.
Photonics Research Group, Dipartimento di Ingegneria Elettrica e dell'Informazione, Politecnico di Bari, Via Orabona 4, 70126 Bari, Italy.
Molecules. 2020 Nov 28;25(23):5607. doi: 10.3390/molecules25235607.
We report on a fiber-coupled, quartz-enhanced photoacoustic spectroscopy (QEPAS) near-IR sensor for sequential detection of methane (CH or C1) and ethane (CH or C2) in air. With the aim of developing a lightweight, compact, low-power-consumption sensor suitable for unmanned aerial vehicles (UAVs)-empowered environmental monitoring, an all-fiber configuration was designed and realized. Two laser diodes emitting at 1653.7 nm and 1684 nm for CH and CH detection, respectively, were fiber-combined and fiber-coupled to the collimator port of the acoustic detection module. No cross talk between methane and ethane QEPAS signal was observed, and the related peak signals were well resolved. The QEPAS sensor was calibrated using gas samples generated from certified concentrations of 1% CH in N and 1% CH in N. At a lock-in integration time of 100 ms, minimum detection limits of 0.76 ppm and 34 ppm for methane and ethane were achieved, respectively. The relaxation rate of CH in standard air has been investigated considering the effects of HO, N and O molecules. No influence on the CH QEPAS signal is expected when the water vapor concentration level present in air varies in the range 0.6-3%.
我们报告了一种光纤耦合的石英增强光声光谱（QEPAS）近红外传感器，用于空气中甲烷（CH 或 C1）和乙烷（CH 或 C2）的顺序检测。为了开发一种适用于无人机（UAV）环境监测的轻量级、紧凑、低功耗传感器，我们设计并实现了一种全光纤配置。两个激光二极管分别在 1653.7nm 和 1684nm 处发射，用于 CH 和 CH 的检测，分别进行光纤组合，并与声学检测模块的准直器端口进行光纤耦合。在甲烷和乙烷 QEPAS 信号之间没有观察到串扰，并且相关的峰信号得到了很好的分辨。该 QEPAS 传感器使用从认证浓度为 1% CH 在 N 和 1% CH 在 N 中生成的气体样品进行校准。在锁定积分时间为 100ms 的情况下，甲烷和乙烷的最小检测限分别达到了 0.76ppm 和 34ppm。考虑到 HO、N 和 O 分子的影响，研究了标准空气中 CH 的弛豫速率。当空气中的水蒸气浓度在 0.6-3%范围内变化时，预计对 CH QEPAS 信号没有影响。
