ORIGINAL RESEARCH article
Front. Phys.
Sec. Optics and Photonics
This article is part of the Research TopicAcquisition and Application of Multimodal Sensing Information, Volume IIIView all 7 articles
A resonant photoacoustic spectroscopy sensor for ppb-level detection of acetylene employing a 1.53 μm laser diode
Provisionally accepted
- Electric Power Research Institute of Guangdong Power Grid Co., Ltd, Guangzhou, China
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A compact and highly sensitive photoacoustic spectroscopy (PAS) sensor for dissolved acetylene (C₂H₂) detection was developed for transformer fault diagnosis applications. A 1.53 μm distributed-feedback (DFB) diode laser targeting the ν₁ + ν₃ absorption line of acetylene at ~1530.37 nm was employed, benefiting from strong line intensity and high transparency of transformer oil in the near-infrared region. Wavelength modulation spectroscopy combined with second-harmonic (2f) demodulation was implemented, and the modulation depth was optimized to 120 mVpp to achieve the maximum normalized 2f signal. A high-Q resonant photoacoustic cell was designed to enhance the acoustic response and improve the signal-to-noise ratio. Experimental results demonstrated excellent linearity (R² = 0.999) over the concentration range of 200–1000 ppm. For a standard 100 ppm C₂H₂/N₂ mixture, a peak 2f signal amplitude of 5.4 × 10⁻⁵ V was obtained, with a noise level of 4.05 × 10⁻⁷ V (1σ). Allan deviation analysis further confirmed the outstanding long-term stability of the system, achieving a detection sensitivity of 0.75 ppm at 1 s and a minimum detection limit of 50 ppb at an integration time of 3200 s. These results indicate that the proposed PAS sensor enables accurate, real-time, and trace-level acetylene detection, demonstrating strong potential for dissolved gas analysis in transformer oil and early warning of incipient arcing faults.
Keywords: Acetylene, Gas sensor, laser spectroscopy, photoacoustic spectroscopy, Photoacustic.
Received: 19 Jan 2026; Accepted: 10 Feb 2026.
Copyright: © 2026 Peng, Qian, Zhao, Wang, Zhao and Fu. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) or licensor are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.
* Correspondence: Lei Peng
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