Photorefractive polymers for 3D display application

Photorefractive (PR) materials are a class of organic and inorganic compounds with the ability to change their index of refraction on illumination. The change in refractive index is both dynamic and reversible: dynamic because no external processing is required for the index modulation to be revealed, and reversible because the index change can be modified or suppressed by altering the illumination pattern. These properties make PR materials very attractive candidates for writing updatable holograms, and a key component in holographic 3D displays. Photorefractivity was initially discovered in inorganic crystals by Ashkin et al. in 1966 [1]. In 1990, Sutter et al. found the effect in an organic compound [2], and Ducharme et al. observed the phenomenon shortly afterward in polymers [3]. Since then, significant improvement in the material characteristics has enabled its use in applications as diverse as image restoration [4], correlation [5], beam conjugation [6], nondestructive testing [7], data storage [8], imaging trough scattering media [9], holographic imaging [10] and display [11], and many others [12].