Abstract

We have previously investigated^1,2 the effects of nonlinear interaction and cross talk between three photoinduced gratings in photorefractive Bi₁₂SiO_20. The three gratings are induced by the interference between one reference beam and two object beams. Cross talk of the order of 50% was measured in the diffusion regime.¹ Recently, from a nonlinear solution to the band-transport model, we explained these effects theoretically for diffusion-dominated recording in Bi₁₂SiO₂₀ (BSO).³ In this paper we show that the nonlinear coupling between gratings can be further optimized in drift dominated BSO Experimentally, we have obtained cross talk larger than 200% for an equal object beam intensity ratio. Using a different object-beam ratio, we show that the nonlinear interaction in the drift regime can be so pronounced that one grating cancels out the another grating. This unexpected strong nonlinear interaction has important consequences for many photorefractive applications with multiple beam interactions, as, for example, in photorefractive optical interconnects and in photorefractive storage.

© 1995 Optical Society of America