Bulk wave excitation from the surface of a LiNbO3 crystal by a system of planar electrodes

Abstract

Ultrasound generation using planar electrodes deposited on the surface of a lithium niobate crystal is investigated. The analysis is carried out in an acousto-optic device based on the XY cut of a lithium niobate crystal and in an acousto-optic cell designed as a prototype of a modulator of non-polarized radiation. The experimental investigation is conducted at different frequencies of the driving electrical signal. The generated acoustic field is visualized by the acousto-optic method at different polarizations of the incident optical beam in case of slow shear and longitudinal acoustic modes. A relation between diffraction efficiencies for ordinary and extraordinary polarized optical radiation is analyzed. The obtained experimental results on the diffraction efficiencies are compared to the theoretically predicted values. It is demonstrated that the polarization characteristics of the devices differ from the conventional characteristics by the dependence on the structure of the acoustic beam.