Monofrequency control of low-frequency quartz resonators by holographic interferometry

The holographic interferometry method has been used for analyzing spectral characteristics of XYS/+3° cut piezoelectric elements of low-frequency quartz resonators. The study of piezoelectric elements of longitudinal vibrators at the resonant frequency f_r=128 kHz has shown that all piezoelectric elements have side resonances at frequencies of 375 kHz, 585 kHz and 635 kHz. The existence of such resonances can be explained by physical nature of acoustic waves propagation in anisotropic bodies and, namely, by the presence of the angle between the acoustic wave front and the propagation direction. Varying the geometric parameters (thickness, width and length) of piezoelectric elements of quartz resonators, it is impossible to eliminate the side resonances, but their amplitude may by attenuated slightly. The holographic time-averaging method has allowed one to visualize the process of volumetric acoustic wave propagation and interaction in piezoelectric elements of low-frequency quartz resonators as well as to analyze the effect of piezoelectric elements geometry on monofrequency