Rewritable Holograms Could Appear in Mobile Phones

Imagine having a mobile phone wallpaper which is not a flat image, but a full 3D-Hologram, which can then be updated by the user just as easily as they currently buy replacement wallpapers. That is the promise which could come from a breakthrough by University of Arizona optical scientists.

They have developed a method of "rewriting" holograms, and while the technique is far too slow for live moving images, it would enable static images (such as wallpapers) to be changed on a whim.

The holographic displays - which are viewed without special eyewear - are the first updatable three-dimensional displays with memory ever to be developed, and while the scientists talk in depth about military applications (understandable as the military funded the work), it is the consumer market which will doubtless leap at this new development.

"This is a new type of device, nothing like the tiny hologram of a dove on your credit card," UA optical sciences professor Nasser Peyghambarian said. "The hologram on your credit card is printed permanently. You cannot erase the image and replace it with an entirely new three-dimensional picture."

"Holography has been around for decades, but holographic displays are really one of the first practical applications of the technique," UA optical scientist Savas Tay said.

Tay, Peyghambarian, their colleagues from the UA College of Optical Sciences and collaborators from Nitto Denko Technical Corp., which is an Oceanside, Calif., subsidiary of Nitto Denko, Japan, report on the research in the Feb. 7 issue of the journal Nature.

Their device basically consists of a special plastic film sandwiched between two pieces of glass, each coated with a transparent electrode. The images are "written" into the light-sensitive plastic, called a photorefractive polymer, using laser beams and an externally applied electric field. The scientists take pictures of an object or scene from many two-dimensional perspectives as they scan their object, and the holographic display assembles the two-dimensional perspectives into a three-dimensional picture.

The researchers also are working to write images even faster using pulsed lasers.

"If you can write faster with a pulsed laser, then you can write larger holograms in the same amount of time it now takes to write smaller ones," Tay said. "We envision this to be a life-size hologram. We could, for example, display an image of a whole human that would be the same size as the actual person."

The four-inch by four-inch prototype display that Peyghambarian, Tay and their colleagues created now comes only in red, but the researchers see no problem with developing much larger displays in full color.

Posted to the site on 6th February 2008