New 'superlens' focus 10 times more sharply than conventional lens

Washington, April 25 : A trio of American researchers has developed a "superlens" that can focus 10 times more sharply than a conventional lens.

Anthony Grbic, Lei Jiang, and Roberto Merlin of the University of Michigan in Ann Arbor say that their invention can provide a solution to the limits of data storage on CDs, shrink the size of features on computer chips, and even enable gadgets to be powered without wires.

The researchers say that a conventional lens cannot focus light down to more than about half its wavelength, something that is scientifically known as "diffraction limit".

They say that they have now devised a very simple design to beat the diffraction limit.

The researchers have revealed that the new lens is a 127-micrometer-thick plate of teflon and ceramic with a copper topping.

"The beauty of these is that they're planar, they're easy to fabricate," New Scientist quoted Grbic as saying.

He said that a single step of photolithography, which is used to etch computer chips, was sufficient to make the new lenses.

The researchers selectively etched away the copper to make many capacitors sandwiched together.

Capacitors are typically used in electronics for storing electric charge for short periods.

However, the researchers have revealed that capacitors used in their lenses interact directly with electromagnetic waves like light, which sets up currents in the capacitors that focus the waves passing through the lens into a point 20 times smaller than their wavelength.

They say that this is 10 times tighter than a conventional lens can achieve, hampered by the diffraction limit.

Grbic says that the current prototype works on microwaves, which are easier to focus because they have longer wavelengths than visible light.

He says that capacitors of various sizes might enable the lens to focus other frequencies like visible and infrared light.

He and his colleagues believe that their lenses may help improve the technique of transferring power wirelessly, which was developed about two years ago.

John Pendry of Imperial College London, who in 2006 proved that invisibility cloaks could be possible, said: "This is an important step forward in sub-wavelength imaging with considerable potential applications."

A paper describing the new invention appears in the journal Science.

ANI