Solution of nonlinear equations for four-wave interactions in photorefractive media

A system of nonlinear equations is solved to describe a four-wave interaction in photorefractive media generating transmission or reflection refractive index gratings in the case of a drift-diffusive nonlinearity mechanism with an arbitrary complex coupling constant. An analysis is made of the four-wave interaction in the geometry of a nonlinear ring resonator where a reflection grating is formed.