Recording a static hologram with laser beams of different frequencies in photorefractive crystals

Abstract
A mechanism for recording a static hologram in photorefractive Bi12TiO20 crystal by a moving interference pattern is studied theoretically and experimentally. The mechanism is the result of detection of the pattern by the phase-locked ac field that is applied to the crystal, and the field's frequency is much greater than the inverse response time of the hologram.