Anisotropy of the acoustooptic figure of merit for LiNbO3 crystals. Isotropic diffraction

TL;DR

This paper analyzes the anisotropy of the acoustooptic figure of merit in lithium niobate crystals under isotropic diffraction conditions, deriving relations and identifying maximum AOFM values influenced by anisotropy and material properties.

Contribution

It introduces a new approach for analyzing AOFM anisotropy in LiNbO3 crystals and derives effective coefficients and maximum AOFM under isotropic AO diffraction conditions.

Findings

Maximum AOFM for LiNbO3 is 11.62x10^-15 s^3/kg.

Maximum AOFM occurs with shear acoustic wave in YZ plane and optical wave polarized in the same plane.

High AOFM values are due to anisotropy and high elastooptic coefficients.

Abstract

We have developed the approach for analyzing of anisotropy of acoustooptic figure of merit (AOFM) for lithium niobate crystals in the case of isotropic acoustooptic (AO) diffraction. The working relations for the effective elastooptic coefficients and the AOFM have been derived. We have found that, under the conditions of isotropic AO diffraction, the maximum AOFM value for LiNbO3 is equal tp 11.62x10-15s3/kg. It is peculiar for the geometry of AO interaction of the shear acoustic wave propagating in the YZ plane (the velocity 3994 m/s) with the optical wave polarized in the same plane. We have demonstrated that the maximum AOFM values are achieved mainly due to essential anisotropy and high values of the elastooptic coefficients of LiNbO3.