Effect of Microgroove Structure on the Performance of QTFs Utilized for Gas Sensing

The quartz tuning fork (QTF), serving as the acoustic-electrical conversion element in quartz enhanced photoacoustic spectroscopy (QEPAS) systems, plays a critical role in determining detection sensitivity. In this study, we establish, for the first time, a comprehensive model of the acoustic-mechanical–electrical transformations in QTFs for gas sensing applications, leveraging this model to optimize their structural design. By enhancing key intrinsic properties of QTFs—such as resonance frequency, quality factor (Q), and surface excitation charge—the optimized design significantly improves the efficiency and sensitivity of gas measurements. Specifically, the influence of microgroove depth and width on the performance of T-shaped QTFs is systematically investigated through theoretical analysis and numerical simulations. Guided by the optimization framework, two sets of QTFs were fabricated: one featuring grooves of varying depths and the other with grooves of varying widths. These QTFs were subsequently employed in trace gas detection experiments to validate the theoretical predictions. The experimental results demonstrate that the T-shaped microgroove QTFs achieve substantial performance enhancements, with signal peak and signal-to-noise ratio (SNR) improvements of up to 234% and 577%, respectively, compared to standard 32.768 kHz commercial QTFs, as evidenced by C₂H₂ measurements.