Photorefractive spatial light modulation by electrocontrolled beam coupling in SBN:Ce crystals

Dynamic incoherent-to-coherent image conversion is proposed, which is based on the effects of electrocontrolled two-beam coupling in SBN:Ce and image spatial modulation of coupling gain. Either negative or positive coherent replica is obtained by altering the electric field. Analysis of the performance is made by coupled-wave theory, which gives the optimum experimental parameters for a grey-level image conversion.