INCOHERENT-TO-COHERENT CONVERSION BY USE OF THE PHOTOREFRACTIVE FANNING EFFECT

A dynamic incoherent-to-coherent converter using the photorefractive f anning effect is demonstrated in a BaTiO3:Ce crystal, and high-quality positive replicas of the incoherent image are obtained with a resolut ion of 32 line pairs/mm. In this method the incoherent image-bearing b eam modulates the transmission intensity of the coherent beam directly , and no readout beam is required. When the intensity ratio of the inc oherent beam to the coherent beam is smaller than 5, the transmission intensity of the coherent beam increases almost linearly with increase d intensity of the incoherent beam. (C) 1997 Optical Society of Americ a.