Simultaneous High-Sensitivity and Rapid-Response Acetylene Detection Using a 3-D-Printed Single-Fiber Photoacoustic Probe

Achieving high detection sensitivity while maintaining rapid response is a persistent challenge in dissolved gas analysis, particularly for fiber-optic photoacoustic sensors constrained by diffusion mechanisms. In this work, we report a simultaneous high-sensitivity and rapid-response acetylene (C2H2) sensor enabled by a novel 3D-printed single-fiber photoacoustic probe. Unlike conventional designs that sacrifice gas exchange speed for acoustic confinement, our probe features a permeable multi-aperture cavity specifically engineered to co-optimize fluid dynamics and acoustic pressure accumulation. Numerical simulations and experimental results demonstrate that this architecture effectively eliminates the gas transport bottleneck, reducing the thermodynamic equilibrium time to just 9.5 s, which is an improvement of over 90% compared to traditional cantilever-based diffusion models. Despite its open structure, the probe maintains exceptional acoustic performance, achieving a detection limit of 21.7 ppb for C2H2within a minimal effective volume of 0.3 mL. Furthermore, the single-fiber configuration is shown to yield a signal amplitude 5 times higher than dual-fiber counterparts by minimizing acoustic energy leakage. These results validate the proposed probe as a robust solution for real-time, high-precision transformer oil monitoring, successfully overcoming the trade-offs inherent in miniature photoacoustic devices.