Quasi-Collinear Acousto-Optic Interaction in Inhomogeneous Acoustic Field

A.V. Maslakov, A.S. Trushin and V.B. Voloshinov Lomonosov Moscow State University, Physics Department, Moscow 119991, Russia

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In studying characteristics of quasi-collinear acousto-optic tunable filters, we observed a new effect not explained by existing theories. As found, at high levels of driving power corresponding to high diffraction efficiency, a transition of energy from a diffracted light beam to a non-diffracted one vanished. In addition, the increase of the acoustic power was accompanied by a significant broadening of the filter frequency bandwidth. This effect could not be described in terms of the traditional consideration of acousto-optic diffraction based on a plane wave approximation and a model of a homogeneous acoustic column. The goal of this research was to develop a mathematical model capable of a correct description of the new effects. The paper examines a case of the quasi-collinear acousto-optic diffraction taking into account the two-dimensional spatial structure of the acoustic field. We gave a theoretical description of the effect of diffracted light beam intensity saturation at high level of acoustic driving power. It was shown that this effect was caused by the diffraction distortion of the acoustic field phase fronts in the plane of the acousto-optic interaction.

DOI: 10.12693/APhysPolA.127.46 PACS numbers: 42.79.Jq, 42.79.Ci, 42.30.-d, 42.25.Fx