Cal scientists bend light to create the invisible

The art of invisibility, which enabled Harry Potter to wander unseen around Hogwarts, may be just around the corner, scientists believe.

Researchers funded by the Pentagon have managed to make material that has the potential to bend light around objects to make them invisible.

By diverting light around an object scientists expect to be able to make tanks, buildings and even individual infantrymen disappear from view.

For the military such a cloak would be the ultimate camouflage, but it would have many other uses, perhaps eventually allowing Harry Potter's invisibility cloak to be merchandised.

In tests carried out in the United States, researchers were able to construct a prism that bent light “the wrong way” and so would make an object appear to vanish. The results of the experiments by scientists at the University of California, Berkeley, and the Lawrence Berkeley National Laboratory, in California, will be published this week in the journals Nature and Science, but the full papers were released early online last night.

Similar techniques using microwaves, which are much easier to control, were demonstrated two years ago, but this is the first time that they have been successfully carried out in three dimensions with visible light.

“This straightforward and elegant demonstration enhances our ability to mould and harness light at will,” researchers said. “Invisibility cloaks get a step closer to realisation, with the demonstration of a new material that can bend visible light the wrong way for the first time in three dimensions.”

The prism used to bend the light was made from metamaterials, substances artificially created using nano-engineering, which refracted it in the opposite direction from the way that it would through a glass prism.

Bending light in the wrong way, negative refraction, is thought to be impossible with naturally occurring materials but the metamaterials, which had a fishnet structure made from silver nanowires, overcame the problem.

Researchers believe that the technique can now be developed to create an invisibility cloak that would direct light waves around an object. To the observer the effect of diverting light around an object would be to hide it because none of the light would reflect off it to give away its position.

The scientists were reassured that little of the light was lost during the process of bending, meaning that high definition would be maintained. This would be important for the development of an invisibility cloak because a fuzzy appearance to a landscape would give away to an observer that something was being hidden.The researchers believe that the technology employed could be used to develop the “perfect lens”, which would be able to reveal objects that are smaller than the wavelength of light.

The experiments are a development of work by Sir John Pendry, Professor of Theoretical Physics at Imperial College, London, who originally outlined how metamaterials could be constructed to cloak objects by deflecting and controlling radiation. He said that in the short to medium term the most likely application of a cloaking device would be to hide objects such as aircraft and tanks from radar.

http://www.timesonline.co.uk/tol/news/uk/science/article4499914.ece

 

Yup. It's called X'tal Vision. Google it.


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