Two-dimensional image edge enhancement in the two-phonon diffraction

We suggest using the two-phonon Bragg scattering regime for two-dimensional image edge enhancement by means of acousto-optic (AO) diffraction on a single sound wave. Image edge enhancement is demonstrated in the first diffraction order by using an AO cell made of the TeO₂ single crystal. To explain this effect, a three-dimensional model of AO interaction is proposed, which takes into account the angular selectivity of diffraction both in the plane of Bragg scattering and in the plane orthogonal to it.