High Tg, Nonpoled Photorefractive Polymers

In recent years, the development of organic materials for optoelectronics and photonics has been continuously progressing, driven by the prospect of manufacturing flexible, low-cost devices with tailorable properties for specific applications. Among the different functionalities investigated, the photorefractive (PR) one is relevant for a variety of applications, ranging from holography1,2 to image processing.3,4 Photorefractive materials are photoconductors in which the space redistribution of charges photogenerated by a nonuniform illumination creates an electric field. In turn, such spacecharge field affects the refractive index if the material exhibits nonlinear optical properties and/or spontaneous (or fieldinduced) birefringence. The resulting hologram is then phaseshifted with respect to the illumination pattern,5,6 a property unique to PR gratings and with important consequences for applications.