Recent Advances in Photorefractive Polymers Jayan Thomas* a , C. W. Christenson b , B. Lynn b , P.-A. Blanche b , R. Voorakaranam b , R. A. Norwood b , M. Yamamoto c and N. Peyghambarian b a NanoScience Technology Center and CREOL, University of Central Florida, Orlando, Florida 32816, USA; b College of Optical Sciences, The University of Arizona, Tucson, Arizona 85721, USA; c Nitto Denko Technical, Oceanside, California 92058, USA. * Jayan.Thomas@ucf.edu ABSTRACT Photorefractive composites derived from conducting polymers offer the advantage of dynamically recording holograms without the need for processing of any kind. Thus, they are the material of choice for many cutting edge applications, such as updatable three-dimensional (3D) displays and 3D telepresence. Using photorefractive polymers, 3D images or holograms can be seen with the unassisted eye and are very similar to how humans see the actual environment surrounding them. Absence of a large-area and dynamically updatable holographic recording medium has prevented realization of the concept. The development of a novel nonlinear optical chromophore doped photoconductive polymer composite as the recording medium for a refreshable holographic display is discussed. Further improvements in the polymer composites could bring applications in telemedicine, advertising, updatable 3D maps and entertainment. Keywords: Photorefractive polymers, holography, 3D display, nonlinear materials, high diffraction efficiency materials. 1. INTRODUCTION The photorefractive (PR) effect, originally discovered in inorganic crystals more than 40 years ago, initially drew attention as a perceived detriment to non-linear applications in these materials [1, 2]. First, the process was reversible though also fixable, allowing both read/write and read-only applications, as opposed to standard photographic films which could only be written once. Second, the non-local nature of the process allowed coupling and energy transfer to occur between two coherent beams. Organic polymer materials compared to inorganic materials have the inherent advantages of ready manipulation of component formulations to suit a given application and low cost [3, 4]. The structural constraints were also relaxed in polymers, allowing them to be custom made into different geometries, and samples can be made much larger than is typical for crystals. The dielectric constant is also smaller, which reduces the electric field screening of trapped charges and increases the quality factor. The highly customizable doping process is also easier compared to crystals, where dopants are typically expelled during crystal growth. PR polymers now outperform inorganic counterparts in diffraction efficiency, two-beam coupling gain, and sensitivity. Due to this tremendous progress many applications have appeared, including optical communication[5] and imaging through scattering media [6], all with different material challenges that can be met by these highly versatile polymers. Recently, they have been shown to function in dynamic holographic displays [7], which are of use in medical imaging, industrial design, defense applications, and air traffic control, among other emerging areas such as telepresence. Unlike other permanent media for recording holograms, PR polymers are reversible and require no post- processing. They demonstrate fast response time, long persistence, and high diffraction efficiency, which are necessary material properties for such an application. However, progress in other areas has not been as rapid, particularly in the area of sensitivity. In the visible, the sensitivity is still orders of magnitude smaller than that of permanent films used for recording static holograms. Here we discuss the recent progress in the field of photorefractive polymers, including new hole-transporting polymers for reduced glass transition temperature (T g ) and high mobility. Particularly, a bis-triarylamine side-chain host polymer exhibits less deep trapping leading to stable dynamics independent of the illumination history. New composites Invited Paper Linear and Nonlinear Optics of Organic Materials XI, edited by Jean-Michel Nunzi, Rachel Jakubiak, Theodore G. Goodson III, Manfred Eich, Proc. of SPIE Vol. 8113, 811302 · © 2011 SPIE · CCC code: 0277-786X/11/$18 · doi: 10.1117/12.897093 Proc. of SPIE Vol. 8113 811302-1 Downloaded from SPIE Digital Library on 02 Dec 2011 to 150.135.248.72. Terms of Use: http://spiedl.org/terms