Plate Acoustic Waves in ZX-cut Lithium Niobate

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Plate acoustic waves (PAW) propagating along X-axis in the Z-cut wafer of a single crystal of lithium niobate are considered theoretically and experimentally. For eight lowest PAW modes, the dispersion curves for wavenumber k(f) are calculated by the equations of motion and electrodynamics, by the Finite Element Method, and then measured experimentally. The spectra k(f) obtained by the numerical solution and FEM-simulation are in good agreement, and experimental measurements agree with theoretical predictions. The PAW modes are identified by the components of their total acoustic displacements and cutoff frequencies. Analysis of the longitudinal and normal acoustical displacements permits to find PAW mode capable for usage in ultrasonic actuators. The results obtained may be useful for ultrasonic transducers, acousto-electronic and acousto-optic applications, and ultrasonic motors/actuators fabricated in the Z-cut ferroelectric lithium niobate wafers including periodically poled wave-guides.