Microcavity-enhanced optoelectronic fiber photoacoustic spectroscopy for ppb-level trace gas sensing

Photoacoustic spectroscopy is a highly sensitive analytical technique for trace chemical detection in gaseous and liquid phases.Conventional systems relying on free-space optics face limitations in light-matter interaction efficiency and electronic integration.To address this, we developed a miniaturized, ultrasensitive photoacoustic spectroscopy gas sensor by integrating a thermally drawn multi-material optoelectronic fiber, a T-type resonant photoacoustic cell, and a MEMS microphone at the fiber tip.This system enables amplified light-gas interactions and simultaneous electrical signal acquisition, achieving ppb-level detection within seconds using sub-microliter sample volumes (0.02 mL).By leveraging mass-producible optoelectronic fibers and MEMS technology, this work establishes a new class of optical sensors featuring compact size, ultrahigh sensitivity, environmental robustness, and scalable multiplexed detection capabilities for harsh environments.