Collinear acousto-optic interaction of optical and acoustic vector beams. Summation of the polarization orders of topological defects

Abstract

We analyze backward collinear acousto-optic (AO) interactions of optical and acoustic vector beams in the centrosymmetric crystals with cubic symmetry. It is shown that the above interactions lead to appearance of diffracted elliptical vector optical beam, which can be transformed into cylindrical vector beam under certain conditions. A summing rule for the polarization orders of interacting beams is formulated. A number of important particular conclusions can be drawn from this general rule: (i) when the interacting optical and acoustic beams have the same modules but the opposite signs of polarization orders, the AO interaction of these beams gives rise to annihilation of topological defect in the diffracted beam, (ii) when, contrary to the incident optical beam, the acoustic beam represents a vector beam, the topological defect of polarization state is transferred from the acoustic beam to the diffracted optical beam in the course of AO diffraction, and (iii) when the incident optical beam is a circularly polarized defect-free beam and the acoustic beam contains a topological defect of polarization state, this defect is transformed into a topological defect of phase of the diffracted optical beam, creating an optical vortex in the course of AO diffraction.