German scientists have created a three-dimensional "invisibility cloak" that can hide objects by bending light waves.

德国科学家近日研制出一种通过弯曲光线来隐藏物体的三维“隐形斗篷”。

Harry¹ Potter. German scientists have created a three-dimensional "invisibility cloak" that can hide objects by bending light waves." width="450" height="275" src="/upimg/100327/4_030442_1.jpg" />
An image of invisibility cloak in Harry Potter. German scientists have created a three-dimensional "invisibility cloak" that can hide objects by bending light waves.

The findings, published in the journal Science on Thursday, could in the future make it possible to make large objects invisible, but for now the researchers said they were not keen to speculate（推测，思考） on possible applications.

"For now these...cloaking devices are just a beautiful and exciting benchmark to show what transformation² optics（光学） can do," said Tolga Ergin of the Karlsruhe Institute of Technology.

Transformation optics use a class of materials called metamaterials（超材料，特异材料） that guide and control light.

In their study, Ergin and his colleagues used photonic（光电子学，光激性的） crystals with a structure that looks like piles of wood to make an invisibility device, or cloak.

They used the cloak to conceal³ a small bump on a gold surface -- a bit like hiding a small object underneath⁴ a carpet and then making both the bump and the carpet invisible.

The "cloak" was composed of special lenses that work by partially⁵ bending light waves to suppress the light scattering⁶ from the bump.

"This is very exciting, because mankind has always thought about being invisible or having invisibility cloaks," Ergin told the reporters in a telephone interview. "This is the first proof of principle. It shows that the technique works."

He added, however, that it would be many years before anything as large as a person, car or tank could be made to disappear with this technique.

"There have been proposals in the field of transformation optics for different devices like beam concentrators（集线器） , beam shifters, super antennas⁷（天线，触角） which concentrate light into one point from all directions, and much, much more," he said.

"It is really hard to say what the future will bring, but the field is definitely very broad and the possibilities are very large."