Twomey Cian F, Biagi Gabriele, Ruth Albert A, Giglio Marilena, Spagnolo Vincenzo, O'Faolain Liam, Walsh Anton J
Centre for Advanced Photonics and Process Analysis, Munster Technological University, Cork, T12 P928, Ireland.
PolySense Lab, Dipartimento Interateneo di Fisica, University and Politecnico of Bari, Bari, CNR-IFN, Via Amendola 173, Bari 70126, Italy.
Photoacoustics. 2024 Jan 22;36:100586. doi: 10.1016/j.pacs.2024.100586. eCollection 2024 Apr.
We present an all-fiber-based laser gas analyzer (LGA) employing quartz-enhanced photoacoustic spectroscopy (QEPAS) and a side-polished fiber (SPF). The LGA comprises a custom quartz tuning fork (QTF) with 0.8 mm prong spacing, two acoustic micro-resonators (mR) located on either side of the prong spacing, and a single-mode fiber containing a 17 mm polished section passing through both mRs and QTF. The SPF polished face is positioned to enable the evanescent wave (EW) to create a photoacoustic wave and excite the fundamental flexural mode of the QTF. Sensor performance was demonstrated using methane in nitrogen gas mixtures, with CH mixing ratios ranging from 75 ppmv to 1% (by volume), measured with an accumulation time of 300 ms, and a minimum detection limit of 34 ppmv subsequently determined. The EW-QEPAS sensor is ideal for miniaturization, as it does not contain any free-space optics and is suitable for gas sensing in harsh environments and where mobility is required.
我们展示了一种基于全光纤的激光气体分析仪（LGA），它采用了石英增强光声光谱技术（QEPAS）和侧面抛光光纤（SPF）。该LGA包括一个定制的石英音叉（QTF），其叉指间距为0.8毫米，在叉指间距两侧各有两个声学微谐振器（mR），以及一根单模光纤，其中有一段17毫米的抛光部分穿过两个mR和QTF。SPF的抛光面的位置设置能使倏逝波（EW）产生光声波并激发QTF的基本弯曲模式。使用氮气和甲烷的混合气体展示了传感器性能，甲烷混合比范围为75 ppmv至1%（体积比），测量累积时间为300毫秒，随后确定最低检测限为34 ppmv。EW-QEPAS传感器非常适合小型化，因为它不包含任何自由空间光学元件，适用于恶劣环境以及需要移动性的气体传感应用。
