Materials design and physics of organic photorefractive systems.

Photorefractivity is an intriguing phenomenon which, however, was initially perceived as a nuisance: Laser illumination generates large internal electric fields which, in turn, modify the optical properties of the material. Useful applications in holographic systems were soon recognized and photorefractivity was subsequently demonstrated in many different materials. These materials span from inorganic crystals to semiconductors, from organic liquid crystals to polymers. Nevertheless, nearly 25 years passed from the discovery of inorganic photorefractive materials in 1966 to reports of the first organic systems. This article reviews the rapid progress of organic photorefractive materials in the last decade and focuses on the different chemical concepts and pathways for further optimization. Advanced systems are required to move photorefractivity out of research laboratories into the market. Possible applications and their first demonstration will conclude the article.