Single-photon entanglement at acousto-optic (acousto-gyration) diffraction

Abstract

We show that a single-photon entanglement can be realized at the collinear acousto-gyration diffraction in optical active and optically uniaxial (or isotropic) media. The entanglement between two degrees of freedom, spin angular momentum and orbital angular momentum, can occur when a standing longitudinal acoustic wave is excited in the above media. This makes it possible to realize four maximum entangled Bell states.