Theoretical Analysis and Experimental Optimization of an Elliptical Acoustic Resonator in Quartz-Enhanced Photoacoustic Spectroscopy

Abstract

We report an elliptical resonator suitable for quartz-enhanced photoacoustic spectroscopy. The theoretical model of the elliptical resonator is first constructed and demonstrates the existence of the eigenmodes in the elliptical resonator. Then the sound field modal distributions for the different eigenmodes in the elliptical resonator are simulated by means of the finite element method. The geometric parameters of the elliptical resonator are experimentally optimized. And the performance of the elliptical resonator is assessed using a high-power multimode laser diode for the NO 2 detection. Due to the high matching efficiency of the spatial profile between the elliptical resonator and the laser beam, the elliptical resonator can achieve a gain factor of 19.2 higher than 5.6 from the circular resonator.

Keywords: Photoacoustic spectroscopy, quartz tuning fork, elliptical resonator, COMSOL