Two-Color Photorefractive.Effect in Lithium Niobate

Abstract

Lithium niobate exhibits a two-color photorefractive effect which provides a mechanism for nondestructive readout in holographic optical data storage. This has been explored using 852nm recording beams and 488nm gating light. For a plane wave transmission geometry, we measured the recording sensitivity, dynamic range, gating ratio and dark decay for crystals of different stoichiometry and degree of reduction, as a function of temperature and optical power density. Increases in stoichiometry and controlled reduction provide sensitivity improvements of~ 1 OOOx over congruent material.