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<div class="quote_poster">Quote:</div><div class="quote_post">LONDON: It began as just a wizard idea from a British scientist. This week it became a reality. And reality began to disappear.
Following in the footsteps of Harry Potter, it was revealed that the world's first invisibility cloak has been tested in America. So far, the device is rather limited - it is 13cm wide and can hide an object only from microwave beams.
But the principle established by John Pendry, a professor at Imperial College London, has been proved to work and in the next five years there are hopes that total invisibility may become possible for larger objects. Tanks, for example.
Laboratory experiments at Duke University, North Carolina, were funded by the US intelligence community.
Using copper rings and metamaterials - artificial composites - it was shown that microwave radiation can be deflected past an object just as water will flow past an obstacle.
When a beam was aimed at the device, sensors were unable to "see" the object hidden in the middle because the microwaves had not bounced back.
"Our cloak allows a concealed volume, plus the cloak, to appear to have properties similar to free space when viewed externally," Duke University professor David Smith said.
"The cloak deflects microwave beams so they flow around a 'hidden' object, making it appear almost as if nothing were there at all. The waves' movement is similar to river water flowing around a smooth rock."
The cloaking device, reported in the online version of the journal Science, was designed by David Schurig of Duke University, who said it had the effect of warping space.
"You cannot easily warp space but you can achieve the same effect on electromagnetic fields using materials with the right response," he said.
"The required materials are quite complex."
He compared the deflection of the microwaves to pushing a knitting needle into a piece of fabric. The threads are pushed aside but do not break.
The US team produced the cloak according to electromagnetic specifications determined by a new design theory proposed by Professor Pendry, 63. The artificial composites in metamaterials react with electromagnetic waves in a way that natural materials would not.
Professor Pendry said: "The real challenge was to make the unusual materials needed for a working device. It's all been done in a time scale much shorter than I had envisaged.
"This cloaking device is just a demonstration showing that you can get radiation where you want it to be.
"There's still some development to do, but I would have thought that in five years you'd be seeing some sort of practical realisation of this technology.
"It's probably too heavy for aircraft, and making objects as big as buildings disappear might be difficult. But it would be ideal for hiding a tank."
Other scientists in the field were impressed by the results, coming just five months after it was announced that cloaking was theoretically possible. </div>
Source
Following in the footsteps of Harry Potter, it was revealed that the world's first invisibility cloak has been tested in America. So far, the device is rather limited - it is 13cm wide and can hide an object only from microwave beams.
But the principle established by John Pendry, a professor at Imperial College London, has been proved to work and in the next five years there are hopes that total invisibility may become possible for larger objects. Tanks, for example.
Laboratory experiments at Duke University, North Carolina, were funded by the US intelligence community.
Using copper rings and metamaterials - artificial composites - it was shown that microwave radiation can be deflected past an object just as water will flow past an obstacle.
When a beam was aimed at the device, sensors were unable to "see" the object hidden in the middle because the microwaves had not bounced back.
"Our cloak allows a concealed volume, plus the cloak, to appear to have properties similar to free space when viewed externally," Duke University professor David Smith said.
"The cloak deflects microwave beams so they flow around a 'hidden' object, making it appear almost as if nothing were there at all. The waves' movement is similar to river water flowing around a smooth rock."
The cloaking device, reported in the online version of the journal Science, was designed by David Schurig of Duke University, who said it had the effect of warping space.
"You cannot easily warp space but you can achieve the same effect on electromagnetic fields using materials with the right response," he said.
"The required materials are quite complex."
He compared the deflection of the microwaves to pushing a knitting needle into a piece of fabric. The threads are pushed aside but do not break.
The US team produced the cloak according to electromagnetic specifications determined by a new design theory proposed by Professor Pendry, 63. The artificial composites in metamaterials react with electromagnetic waves in a way that natural materials would not.
Professor Pendry said: "The real challenge was to make the unusual materials needed for a working device. It's all been done in a time scale much shorter than I had envisaged.
"This cloaking device is just a demonstration showing that you can get radiation where you want it to be.
"There's still some development to do, but I would have thought that in five years you'd be seeing some sort of practical realisation of this technology.
"It's probably too heavy for aircraft, and making objects as big as buildings disappear might be difficult. But it would be ideal for hiding a tank."
Other scientists in the field were impressed by the results, coming just five months after it was announced that cloaking was theoretically possible. </div>
Source
