Monday, September 29, 2008

Physicists draw up plans for real 'cloaking device

19:00 25 May 2006 news service
Zeeya Merali

Physicists are attempting to create a device that could render objects invisible to the human eye. Objects become visible to our eyes due to the way light normally bounces off its surface. Physicist John Pendry and colleagues at Imperial College London, UK, are attempting to create materials, know as metamaterials that will have abnormal optical properties. Metamaterials are composites that are made from electronic components that can be engineered to control the way light travels through them. Pendry's team are calculating that due to its unique shape, light could pass around an object and make it appear as if it was not there. Pendry and his colleagues have drawn up plans for a spherical metamaterial that could potentially render an enclosed object invisible to the eye. In theory; Pendry’s team discusses the types of material properties needed at each point, but the challenge is to match the theory requirements with actual material.

In the past, others have drawn designs for invisibility cloaks. The idea was to calculate exactly how light is scattered off an objects surface, and attempt to design a material to exactly cancel the light reflection. Pendry says that his idea will be different because past designs could not be used for cloaking multiple objects under the same cloak. The difficulty with Pendry’s team design is that it will only work at wavelength larger than visible light. To get by this obstacle Pendry’s team will have to create metamaterials at the nanoscale. Working with materials at a nanoscale makes it “far more difficult to control the metal’s properties,” said team member David Smith. However, he believes that cloaking could become a reality within the next decade.

By: Danny Brown

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