Plate Acoustic Waves in ZX-cut Lithium Niobate

TL;DR

This study combines theoretical, numerical, and experimental approaches to analyze plate acoustic waves in Z-cut lithium niobate, identifying modes suitable for ultrasonic device applications.

Contribution

It provides a comprehensive analysis of PAW modes in Z-cut lithium niobate, including dispersion curves and mode identification, aiding ultrasonic device design.

Findings

Numerical and experimental spectra are in good agreement.

Identified PAW modes suitable for ultrasonic actuators.

Theoretical predictions match experimental measurements.

Abstract

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.