We present a theory of resonant photorefractive wave coupling in cubic phot
orefractive crystals that are in general optically active. This theory incl
udes the resonance enhancement of the photorefractive response in a constan
t applied electric field, the influence of photoelasticity, and the spatial
inhomogeneity of the light intensity. In a unified manner, it allows one t
o describe the polarization and energy properties of two-wave coupling for
the optical configurations relevant to experiment. Applications of the theo
ry are given to photorefractive crystals of the sillenite family. (C) 2000
Optical Society of America [S0740-3224(00)00206-X].