Rewritable Holographic Display

24 02 2008

Researchers claim to have developed rewritable holographic displays!

The iconic image of three-dimensional holography—Princess Leia inserting Death Star blueprints into R2-D2 and intoning, “Help me, Obi-Wan Kenobi. You’re my only hope”—may be just a few years away from reality, says a researcher who has developed a method to write, erase, and rewrite holographic images.

Holographic motion, as featured in Star Wars, has long been confined to the realm of science fiction. But now, according to Nasser Peyghambarian, a professor of optical sciences at the University of Arizona, “we can see we are pretty close to that.”

Peyghambarian and his colleagues at Arizona have found a way to create holograms that can persist for hours but can also be erased and written over. The group worked with researchers from Nitto Denko Technical Corp., in Oceanside, Calif., the research arm of a Japanese company that makes semiconductor and optical products.

Conventional holograms are written using a laser beam split into two out-of-phase beams. One beam bounces off the object being imaged before it recombines with the other beam to create an interference pattern. When that pattern strikes the holographic medium—usually a photosensitive polymer—the material undergoes chemical changes that alter its index of refraction. If you shine a light on the finished hologram, the refraction pattern recreates a 3-D image of the original object. But because the chemical change is nonreversible, these standard materials can be written on only once.

IEEE 

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