Dynamic solutions of the photorefractive two-wave coupling at large modulation depths

An analytical solution of the dynamic coupled wave equations as a function of time in a photorefractive medium at large modulation depths is presented by using the empirically corrected function introduced by Kawk et al. [Optics Commun. 105 (1994) 353-358]. The expression for the response time of two-wave coupling at large modulation depths is also presented. It shows that the response time is dependent on both the material parameters and experimental parameters. The dynamic two-wave mixing gain for large modulation index is developed. The theoretical analysis shows good agreement with the experimental results in the doped KNSBN crystal for the whole range of modulation m.