Photorefractive incoherent-to-coherent optical converter based on anisotropic self-diffraction in BaTiO3

A photorefractive incoherent-to-coherent optical converter (PICOC) is demon strated; conversion is accomplished by anisotropic self-diffraction in BaTi O3. The setup of the PICOC is easy, and only two writing beams are required . The diffraction efficiency reaches 50%, and the resolution is 22 line pai rs (lp)/mm in a typical-size crystal. Further, the resolution reaches 40 lp /mm when a BaTiO3:Rh crystal of thickness 1.2 mm is used, and the diffracti on efficiency is as high as 51%. The resolution of the PICOC can be increas ed effectively by reduction of the crystal thickness with no penalty for lo w diffraction efficiency. (C) 1998 Optical Society of America.