London, February 7 : University of Arizona optical scientists say that they have devised a way to create three-dimensional holographic displays that can be erased and rewritten within minutes.
The researchers claim that they are the first to develop three-dimensional displays with memory. This feature of the holographic displays makes them idea tools for medical, industrial, and military applications that require "situational awareness", they say.
According to the researchers, one will require special eyewear to view dynamic holographic displays developed by them.
"This is a new type of device, nothing like the tiny hologram of a dove on your credit card. The hologram on your credit card is printed permanently. You cannot erase the image and replace it with an entirely new three-dimensional picture," Nature magazine quoted UA optical sciences professor Nasser Peyghambarian as saying.
"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.
The researchers envision that dynamic hologram displays may be made into devices that help surgeons track progress during lengthy and complex brain surgeries, show airline or fighter pilots any hazards within their entire surrounding airspace, or give emergency response teams nearly real-time views of fast-changing flood or traffic problems.
They also expect such displays to be important part of the advertising and entertainment industries in near future.
"Imagine that when you walk into the supermarket or department store, you could see a large, dynamic, three-dimensional product display," said Peyghambarian.
The creators of the new device say that it basically consists of a special plastic film sandwiched between two pieces of glass, each coated with a transparent electrode. Using laser beams and an externally applied electric field, the images are "written" into the light-sensitive plastic called a photorefractive polymer, they say.
Pictures of an object or scene from many two-dimensional perspectives are clicked and scanned, after which the holographic display assembles the two-dimensional perspectives into a three-dimensional picture, say the scientists.
As compared to the traditional holographic displays that did not allow earsing and updating of the images, says Peyghambarian, the new display can show a new image every few minutes.
"We use highly efficient, low-cost recording materials capable of very large sizes, which is very important for life-size, realistic 3D displays. We can record complete scenes or objects within three minutes and can store them for three hours," Peyghambarian said.
The research team is presently 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. 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," Tay said.
While explaining how important of updatable holographic displays could be for medicine in future, Tay said: "Three-dimensional imaging techniques are already commonly used in medicine, for example, in MRI (Magnetic Resonance Imaging) or CAT scan (Computerized Axial Tomography) techniques."
"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-colour 3D holograms, every hospital in the world will want one," Tay added.