Permanently poled fully functionalized photorefractive polyesters

Crystallization and phase separation are severe degradation mechanisms of photorefractive (PR) guest-host systems. Additionally, the response time of PR guest-host systems is in some cases limited by a large contribution of slow chromophore reorientation to the PR effect. The synthesis of fully functionalized systems with glass transition temperatures well above room temperature is a way to restrict these degradation mechanisms and to reduce the PR effect to a pure charge generation and transport phenomenon. We present novel, fully functionalized PR polymers based on polyester. Permanent poling of the systems is demonstrated and quantitatively investigated. The PR properties are measured by degenerate four-wave mixing and two-beam coupling experiments as a function of the external electric field and the degree of permanent poling. One of the systems shows response times of approximately 200 ms with Delta n = 1 x 10(-3). To our knowledge, this work presents the first characterization of PR efficiencies for fully functionalized polymers as a function of the permanent Pockels coefficient chi((2)) (-omega;omega, 0). (C) 1998 Optical Society of America [S0710-3224(98)01310-1].