Abstract

The large modulation effects^1-2 and intensity-dependence^3,4 of the two wave mixing (TWM) gain in versatile photorefractive crystals have been investigated by several researchers independently. In this paper, we present the nonlinear dependences of the TWM gain both on the large modulation depth and on the incident intensity in BaTiO₃ crystal. The gain coefficient Γ is related to the imaginary part of the space- charge field E_SC, which is proportional to the modulation depth m in the linear modulation theory. Refregier et al,¹ developed an empirical correction function f(m) to replace the modulation depth m in the space- charge field expression in order to describe the nonlinear dependence of the TWM gain on modulation depth expressed by:

© 1994 Optical Society of America