Quartz-Enhanced Photoacoustics and Photothermetal Spectroscopy for Gas Sensing and Application

Gas sensors are important for multiple application scenarios, such as chemical substance detection and environmental pollution monitoring. The developments of quartz tuning fork (QTF) based quartz-enhanced photoacoustic and photothermal spectroscopy (QEPAS/QEPTS) in our research group was reported. With respect to QEPAS, a novel QTF-embedded off-beam QEPAS (E-OB-QEPAS) spectrophone configuration was used to improve sensitivity and the strength of acoustic coupling, and decrease the difficulty in assembly process and alignment process. Based on E-OB-QEPAS spectrophone, a sensitive methane sensor system and a double-gas methane/acetylene sensor system were developed. With respect to QEPTS, an all-fiber QEPTS configuration was used to solve the problems of huge size, optical light path alignment and integration process in free-space QEPTS. Then, a wavelength-locked QEPTS-based methane sensor system was proposed by utilizing a fiber-coupled sensing probe for long-distance in-situ gas sensing. At last, a double spot-ring Herriott-cell was used to realize a wide detection range and high detection sensitivity simultaneously in QEPTS-based gas sensor system.