Light-induced thermoelastic sensor for ppb-level H2S detection in a SF6 gas matrices exploiting a mini-multi-pass cell and quartz tuning fork photodetector

Bo Sun; Pietro Patimisco; Angelo Sampaolo; Andrea Zifarelli; Vincenzo Spagnolo; Hongpeng Wu; Lei Dong

doi:10.1016/j.pacs.2023.100553

Light-induced thermoelastic sensor for ppb-level H₂S detection in a SF₆ gas matrices exploiting a mini-multi-pass cell and quartz tuning fork photodetector

Photoacoustics. 2023 Aug 31:33:100553. doi: 10.1016/j.pacs.2023.100553. eCollection 2023 Oct.

Authors

Bo Sun^{1

2}, Pietro Patimisco², Angelo Sampaolo², Andrea Zifarelli², Vincenzo Spagnolo^{1

2}, Hongpeng Wu^{1

2}, Lei Dong^{1

2}

Affiliations

¹ Laboratory of Quantum Optics and Quantum Optics Devices, Institute of Laser Spectroscopy, Shanxi University, Taiyuan 030006, China.
² PolySense Lab-Dipartimento Interateneo di Fisica, University and Politecnico of Bari, Via Amendola 173, Bari, Italy.

Abstract

We present an optical sensor based on light-induced thermoelastic spectroscopy for the detection of hydrogen sulfide (H₂S) in sulfur hexafluoride (SF₆). The sensor incorporates a compact multi-pass cell measuring 6 cm × 4 cm × 4 cm and utilizes a quartz tuning fork (QTF) photodetector. A 1.58 µm near-infrared distributed feedback (DFB) laser with an optical power of 30 mW serves as the excitation source. The sensor achieved a minimum detection limit (MDL) of ∼300 ppb at an integration time of 300 ms, corresponding to a normalized noise equivalent absorption coefficient (NNEA) of 3.96 × 10^-9 W·cm^-1·Hz^-1/2. By extending the integration time to 100 s, the MDL can be reduced to ∼25 ppb. The sensor exhibits a response time of ∼1 min for a gas flow rate of 70 sccm.

Keywords: H2S detection; Light-induced thermoelastic spectroscopy; Quartz tuning fork; Sulphur hexafluoride.