Novel photorefractive polymer composites with broad optical transparency and enhanced optical storage time

摘要

The photorefractive (PR) effect is observed in certain materials which form an internal space-charge field upon illumination and possess electro-optic properties. It allows for a formation of refractive index gratings characterized by high angular and wavelength selectivities. Numerous applications including real-time image processing and optical . data storage can be implemented by utilizing the PR effect. Recently, PR polymers have emerged as a new class of inexpensive and efficient media. Optical image processing1, and high density holographic data storage2 have been demonstrated in PR polymer systems. Until now, very few polymer materials, however, have been reported to exhibit efficient PR response in a broad wavelength range3, for example, from the blue to the red-regions of the visible spectrum. Also, the quasirnondestructive readout of a PR grating in a polymer composite has been reported, but it was achieved at relatively low intensity of the reading beam (i.e. 2xlO'J W/cm2)4. An efficient PR response in a broad wavelength range is desirable for numerous applications i.e. multi-color optical image processing. Also, the recording of efficient PR gratings characterized by a long life-time and minimized cross-talk is essential for the high density optical storage of information.