Optimal Properties Of Photorefractive Materials For Optical Data Processing

The charge transport model of photorefractivity is used to evaluate four figures of merit that can be employed to characterize the performance of photorefractive materials. The figures of merit are the steady-state index change, the response time, the energy per area to write a grating with 1% diffraction efficiency, and the index change per absorbed energy per unit volume (photorefractive sensitivity). These indices are evaluated as a function of grating period and applied external electric field for Bi12Si020, a fast material with a relatively small electro-optic coefficient, and BaTiO3, a slower material with a much larger electro-optic coefficient. Methods for optimizing the mate-rials are discussed.