查看文章

The exact solutions of the set of nonlinear coupled differential equations pertaining to Bragg and non-Bragg orders for the case of interacting angular spectra in a photorefractive medium are obtained numerically. An iron doped lithium niobate is used as a photorefractive material, and the incident wavelength is taken to be 514 nm. During traditional two-beam coupling within a photorefractive material, many non-Bragg orders may also be generated. For solving the set of coupled equations numerically, interactions between the spectra of two Bragg and two non-Bragg orders are considered. The spatial evolution of the spectra of these diffracted orders hence their spatial profiles are studied numerically for different incident profiles.