We present data showing a nonlinear photorefractive response at high modulation depths in a Bi<sub>12</sub>TiO<sub>20</sub> sample when applied ac fields are used. The data are interpreted by means of both a numerical finite-difference model and an analytic theory developed by Swinburne <i>et al</i>. [IEE <i>Proceedings of the International Conference on Holographic Systems, Components and Applications</i> (Institution of Electrical Engineers, London, 1989), p. 175]. Both models provide physical insights into the performance of semiconductor and sillenite materials with ac field enhancements.
© 1992 Optical Society of America
James E. Millerd, Elsa M. Garmire, Marvin B. Klein, Barry A. Wechsler, F. P. Strohlkendl, and George A. Brost, "Photorefractive response at high modulation depths in Bi12TiO20," J. Opt. Soc. Am. B 9, 1449-1453 (1992)