HOLOGRAPHIC STORAGE IN CONJUGATED-POLYMER COMPOSITES

We report on holographic storage with relatively high diffraction effi ciencies in films (2 mu m to 20 mu m thick) of conjugated polymer/glas s and conjugated polymer/polymer composites with emphasis on the forme r. An index of refraction change Delta n as high as 8.6X 10(-3) was ob tained. The grating formation was attributed primarily to the photochr omic effect. However, the anomalous large two-beam coupling that was o bserved in these materials cannot be explained by a photochromic mecha nism. This, together with the small nonlinear electro-optic coefficien t r(eff)=0.42 pm/V may suggest that a weak photorefractive process als o contributes to the hologram formation in these materials. Holograms written on these conjugated polymer composite films are stable in the dark for (at least) one year.