Abstract

We investigate the dynamics of four-wave mixing processes in photorefractive crystals, assuming the phase conjugation condition. We solve numerically the coupled four-wave mixing equations in paraxial approximation under the appropriate boundary conditions using our beam-propagation method [1]. Our analysis includes the dynamical evolution of diffraction gratings in the crystal as well as spatial effects caused by diffraction and by the non-collincar propagation of the four beams. A similar model has recently been used by us to study the dynamical behaviour and the operation principle of double phase conjugation: [1]. The application of a static electric field E_o across the crystal changes the dynamical behaviour of the phase conjugation process. Normally, an external field is applied to restore a π/2 phase shift between the interference fringes and the diffraction grating, enhancing the process of optical phase conjugation.

© 1996 IEEE