hologram-nature-080206

Image of the updateable holographic 3D display, showing a 3D model of an ethane molecule. ((Savas Tay, University of Arizona/Nature))

A team of U.S. scientists announced a technique for changing and updating three-dimensional holographic images, an innovation that could one day lead to virtual surgery and other useful applications.

Writing in this week's issue of Nature, University of Arizona optical scientists said their results could be a breakthrough for the practical use of holographic displays and holograms, which previously have been limited to static images.

"This is the largest photorefractive 3D display to date," the authors said of the 12 cm by 12 cm display. "It can be recorded within a few minutes; viewed for several hours without the need for refreshing; and can be completely erased and updated with new images when desired."

With regular holograms — such as the dove in flight pictured on some credit cards — scientists shine a series of lasers on a photopolymer, chemically altering the substance to make light bounce off the material in different ways depending on the angle observed, producing the 3D effect that tricks the eye. But such images, once created, are static.

The new device uses a different method, with the key ingredient being a special film, called a photorefractive polymer, sandwiched between two pieces of glass covered with transparent electrodes.

This polymer contains a dye that responds to light and rotates in response to an external electric field. The result is a display that looks like a regular hologram but can be updated in the same manner one can write over data on a computer disk.

Full-color, 3D holograms will be all the rage

The technology could be used for everything from military field simulations, keyhole surgery, advertising billboards or immersive 3D entertainment, wrote Georgia Institute of Technology chemistry professor Joseph Perry in an accompanying article.

"For film fans and gamers itching to be in the midst of the action, the wait might not be too long," he wrote.

The new technology has a number of practical applications but is especially attractive to the medical industry, said University of Arizona optical scientist Savas Tay, one of the authors of the paper.

"Three-dimensional imaging techniques are already commonly used in medicine, for example, in MRI or CAT scan techniques," Tay said in a statement. "However, the huge amount of data that is created in three dimensions is still being displayed on two-dimensional devices, either on a computer screen or on a piece of paper. A great amount of data is lost by displaying it this way."

"So I think when we develop larger, full-color 3D holograms, every hospital in the world will want one," he said.