ELECTRIC-FIELD-SWITCHABLE STRATIFIED VOLUME HOLOGRAMS IN PHOTOREFRACTIVE POLYMERS

Two- and four-layer stratified volume holograms have been fabricated from the photorefractive polymeric material poly(methyl methacrylate): (1,3-dimethyl-2,2-tetramethylene-5-nitrobenzimidazoline):C-60 and characterized by holographic four-wave mixing experiments. Coherent addition of diffracted fields from the individual layers is observed, leading to a diffraction efficiency that increases with the square of the active layer thickness. Electric-field switching of the diffraction efficiencies of individual layers is demonstrated. diffraction efficiency is also characterized for one, two, and four active layers. narrows with increasing total structure thickness in agreement with theory.