Soliton Profile of the Dynamic Grating Amplitude and its Alteration by Photorefractive Wave Mixing

The wave-mixing problem is considered with respect to the amplitude of the dynamic grating forming in photorefractive crystals. For non-local response and transmission geometry the grating amplitude dynamics is described by a sine-Gordon equation. Hence the grating amplitude has a soliton form. For an experimental verification the spatial distribution of the grating amplitude was imaged within a LiNbO3 sample by a topographic set-up. The results on changes of the profile of the grating amplitude versus input intensity ratio were in good qualitative agreement with the theoretical prediction. Such alterations of the grating amplitude profile can possibly be applied to signal processing.