INTENSITY DEPENDENCE OF STATIONARY ENERGY-TRANSFER IN DEGENERATE 2-WAVE MIXING IN A REFLECTION GEOMETRY WITH PHOTOREFRACTIVE CRYSTALS

A numerical study of the intensity dependence of the stationary energy transfer in DTWM in a reflection geometry is described. A simplified theoretical model similar to and stemmed from that in a previous work is used. In addition, the effect of absorption on the energy transfer at the non-saturation stage is investigated. The difference in geometry gives rise to some unique features in the DTWM in a reflection geometry such as the dependence of the effective coupling constant g on the depth in the crystal. At the intermediate stage (before saturation), the intensity dependence of the energy transfer gives rise to a smaller value of gamma //o. This is equivalent to a smaller effective coupling strength g//sl (or a smaller thickness l if g//s is kept unchanged). It can be seen that the intensity dependence of g has an adverse effect on the energy transfer in DTWM. The effective coupling constant g as a function of z is computed and plotted in Fig. 3 with the incident intensity I//1//0 as a parameter.