Researchers from the University of Arizona, in conjunction with Nitto Denko Technical Corporation (Oceanside, CA), have created a holographic three-dimensional (3-D) display that can record and display new images every few minutes. The display can record an image in a matter of minutes, can be viewed for several hours without the need to refresh or wear special eyewear, and can be erased and updated with new images when desired.

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The key, according to researcher Savas Tay, is the photorefractive polymers on which the display is based. To be suitable for 3-D displays, photorefractive polymers must have nearly 100% diffraction efficiency, fast writing time, hours of image persistence, rapid erasure, and large area—a combination of properties that was not available before. Tay and colleagues have developed a composite that consists of a copolymer with a hole-transporting moiety and a carbaldehyde aniline group, attached through an alkoxy linker. Images are written into the polyacrylate tetraphenyldiaminobiphenyl-type polymer using a 532 nm laser and an externally applied electric field. The scientists take pictures of an object or scene from many 2-D perspectives, and the holographic display assembles the two-dimensional perspectives into a 3-D picture. The nonlinear optical properties were achieved by adding a fluorinated dicyanostryrene chromophore. The composite was formed into thin-film devices by melting it between two indium tin oxide-coated glass electrodes. The resulting prototype is the largest photorefractive 3-D display achieved to date (4 × 4 in.) and is scalable to full parallax and color. Contact Savas Tay at savas.tay@optics.arizona.edu.

Sat Mar 01 00:00:00 CST 2008