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Washington, July 21
Scientists, including one of Indian origin, have developed a new way to make low-cost holograms that are more realistic, bringing the chess game played in the Star Wars series closer to reality.
The team, led by associate professor Rajesh Menon from University of Utah in the US, found a way to create inexpensive full-colour 2D and 3D holograms that can be viewed at wider angles than current holograms.
The applications for this technology could be wide- ranging, from currency and identification badges to amusement rides and advertisements.
“You can have rich colours at high efficiency, with high brightness and at low cost. And you don’t need fancy lasers and complicated optics,” Menon said.
Typically, the projection of any image, whether it is two or three dimensional, is inefficient because when white light shines on an object, we can only see the reflected colour that bounces back to our eyes while the rest of the colours of the spectrum are absorbed.
Therefore, there is a lot of wasted light. With a typical LCD projector, for example, you may only see as little as 5 per cent of the total light at one time.
Scientists have discovered a better way that borrows from the same principle behind how wings of certain butterflies display their colours.
Instead of reflecting only the colours you see while absorbing the rest, all of the white light is redirected so you see the wavelengths of the wing’s colours at different locations. None of the light is absorbed and therefore wasted.
Using sophisticated algorithms and a new fabrication method, the engineers can create holograms that do the same thing – redirect colours to appropriate locations – instead of absorbing most of it to project much brighter photographic images either in 2D or 3D and with full, natural colours.
Currently, full-colour holograms require lasers to not only make them, but also to view them. Menon’s holograms can be viewed with regular white light.
Most importantly, these holograms can be viewed from any angle, and the image detail does not change, much like a real object.
Such technology could be used on currency notes with security holograms that produce more lifelike images.
It also could be used for identification badges, driver’s licenses and security documents like passports in which an officer could use just a flashlight to authenticate it instead of a special light such as an infrared scanner.
Researchers have only produced 2D still images with their technology so far, he said it wouldn’t be difficult to take the next step to create full-colour 3-D moving images similar to the holographic chess pieces in the movie Star Wars.
Therefore, the holograms could be utilised in entertainment, such as for virtual reality headsets, for movie theatres that would not require powerful projector lamps and it could be an avenue for glasses-less 3D movies or for amusement rides that use high-tech special effects.
