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Friday, 6 April, 2001, 13:14 GMT 14:14 UK
Novel material bends light the wrong way
UCSD
Microwaves come out of the material in the "wrong" direction
By BBC News Online science editor Dr David Whitehouse

Physicists have produced a material with curious refractive properties that defies conventional behaviour.

Microwaves pass through the material in directions contrary to the standard law of deviation for other substances.

Although the strange material is a combination of plastic and copper and has its effect only at microwave frequencies, if it could be made to work with visible light it would have many applications.

Scientists say it could form the basis of many new technologies, including the creation of a perfect lens.

Unique properties

Physicists at the University of California, San Diego (UCSD), US, who last year predicted this new class of composite material, have now experimentally verified its remarkable properties.

Their work demonstrates that electromagnetic radiation travels through the composite material in a manner never before seen in nature.

Physicists made a small sample of the material, a latticework of plastic and copper wires and rings, and sent through it microwave radiation of the same frequency as that used in police radar guns.

The researchers saw the microwaves emerge from the sample in the wrong direction: a direction opposite to that predicted by Snell's law, the well-known rule that describes the way electromagnetic radiation travels through materials.

Possible applications

The achievement is more than a scientific curiosity. The new material could prove useful in the development of novel antennae and other electronic devices.

At the moment, it is opaque to visible light but if a similar substance could be made that was optically transparent it would have many uses. It would make possible the construction of a perfect lens, capable of focusing light and other forms of radiation to limits not possible with current technology.

The material would also have the odd property that a small flashlight shining on a flat slab of the substance would produce a focus at a point on the other side.

Technically, scientists say that this is the first demonstration of any material which has a negative index of refraction. Patents have been applied for.

The research is described in the journal Science.

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