Effect of applied electric fields on the writing and the readout of photorefractive gratings

Abstract

We explore theoretically and experimentally how applying an electric field to a photorefractive crystal affects the recording and the readout of a hologram. We present a unified theory that describes several electric-field-related mechanisms relevant to photorefractive crystals, including amplitude coupling, phase coupling, linear and nonlinear electro-optic effects, and the piezoelectric effect. We analyze the influence of these different effects on the Bragg selectivity and the diffraction efficiency and derive general analytical expressions describing the Bragg detuning effects. Finally, we compare the theory with experiments that we have performed in a strontium barium niobate crystal by recording and retrieving holograms in the presence of an applied electric field.