Light-recording plastic holds up

For more than a decade researchers have been developing inexpensive materials that can record the interference patterns of lightwaves including the complicated patterns of holograms, but these polymers tend to degrade with use.

Researchers from the University of Arizona and Nitto Denko Technical Corporation have made stable photorefractive polymers that promise practical, inexpensive holographic data storage and real-time image processing.

Recording media made using the polymers would make it possible for today's commercially-available video cameras to correct for atmospheric turbulence and take images through fog, clouds and smoke, according to the researchers.

The polymer, which consists of a polyacrylate backbone and tetra-phenyl-diphenyldiamine side units, readily produces and transports positive-charge-carrying holes. This is the key property needed for storing the light and dark areas of light interference patterns.

The researchers found that the material retained its performance after 160,000 50-millisecond write-erase cycles produced at 0.5 watts per square centimeter. The polymers also have a high dynamic range -- meaning they can record a wide range of exposures from dark to light -- and long shelf life at room temperature, according to the researchers.

There is a lot to be done before the material is ready for commercial applications, according to the researchers. The recording-erasing process needs to be more closely controled, and the electric fields needed for operation must be reduced. Also, faster materials would enable telecommunications and biological imaging applications.

The work appeared in the September 13, 2004 issue of Applied Physics Letters.