Elliptical Acoustic Resonator-Based Dual-Quartz-Enhanced Photoacoustic Spectroscopy Sensing

This paper presents a dual-quartz-enhanced photoacoustic spectroscopy (D-QEPAS) sensor based on an elliptical acoustic resonator (EAR) for the first time. The sensor, leveraging the acoustic focusing characteristics of the EAR and a synchronous detection mechanism with dual quartz tuning forks (QTFs), effectively resolves the low acoustic energy utilization issue in traditional QEPAS systems. Dual QTFs were positioned at the two focal points within the EAR to achieve efficient acoustic energy collection and signal superposition. An EAR theoretical model was established and calculated using the finite element analysis method for performance optimization. With acetylene (C₂H₂) as the target gas, results demonstrate that the signal intensity of the EAR-based D-QEPAS system exhibits an approximately 13.05x enhancement compared with the traditional QEPAS system. Allan deviation analysis indicates that this system achieves a detection limit of 134 ppb at an average time of 500 s.