Bending light may be secret behind creating 'invisibility cloak'

Melbourne, July 25 : British researchers say that an "invisibility cloak" that can hide anything may be realised by reflecting light back towards the viewer.

Professor John Pendry and Dr Jensen Li from Imperial College London say that to cloak an object in visible light "requires some clever nanotechnology", which would come from combining special layers of common silica and silicon, each of which reflects light differently.

"It's a lot like a mirage. The sun heats the air above the desert and creates a temperature gradient, so when light from the sky comes down the graded refraction bends the light and it enters your eye and you see a mirage the looks like water," ABC Online quoted Pendry as saying.

The researcher duo says that rather than creating a temperature gradient that only partially reflects light, the silicon and silica mix would create a physical gradient that makes light do a complete U-turn, exiting in the same direction it entered.

According to the researchers, this result would look like a mirror, which would show a viewer his/her own reflection.

They say that such a mirror would let one check one's reflection from any angle, not just one.

"This new cloak is not perfect," says metamaterial researcher Professor Vladimir Shalaev from Purdue University, Indiana, who did not contribute to the paper.

"Instead it leaves an observer with an illusion that there is only a flat mirror on the ground with some transparent dielectric box on top of it, whereas, in reality, there is an object concealed in the 'transparent' box which is not visible for the observer," Shalaev added.

Terming this theory as an important result, he said: "This 'invisibility carpet' can be fabricated and it's indeed an important step toward making the dream of invisibility true."

Pendry reckons that appropriate funding and expertise may enable the production of invisibility carpets in one to two years.

"We are theorists; we have an easy life. The difficult stuff is to actually make this," said Pendry.

ANI