Blueprint of the nanostructure containing the bump in the gold carpet and tailored invisibility cloaking structure underneath
The development of invisible cloaks are many years away from becoming a reality, but some researchers in Germany are working in a new field that could also lead to more powerful microscopes and harness light to make electricity.
The field is called transformation optics. Researchers are using nanotechnology, in which they create extremely small items from metal, electrons and semiconductors, to bend light from all distances and in many different directions so it becomes invisible to the naked eye.
German researchers Karlsruhe Institute of Technology demonstrated the potential to hide objects from detection by bending light in three dimensions to conceal a small bump on a gold surface that, like a carpet, overlaid a nanostructure made up of particles like a pile of wood. The gold surface also became invisible in nearly visible infrared light.
Vladimir Shalaev is a professor of electrical and computer engineering at Purdue University in Indiana. He says light travels along a single path from one point to another. But transformation optics, according to Shalaev, bends light around objects like water around a rock in a stream.
"What we are trying to do is to bend it, to turn it around the corner, to get sucked in certain area[s] that's just been excluded from certain area[s] that's the idea behind cloaking," said Vladimir Shalaev.
Shalaev says transformation optics could also someday be used to create very powerful microscopes, ten times more powerful than an electron microscope, by focusing it in a particular area, and converting sunlight into electricity.
"When you concentrate it in an extremely small area and that could be just for a very efficient conversion of light into electricity, that's photovoltaics," he said. "And since people are now so keen in energy, that could be a very efficient way to instantly convert light energy into electrical energy."
German scientists say it would take a long time to scale up the technology to completely hide an object although such techniques could be developed in the future.
Until now, cloaks have been developed to conceal objects in two dimensions, but they create a shadow that can be detected with instruments.
This is the first time researchers have hidden an object in three dimensions, according to Purdue University Vladimir Shalaev, who marvels at the accomplishment.
"Their structure is just beautiful in terms of the fabrication," said Shalaev. "It's just spectacularly nice."
The study on transformation optics and its potential uses were published this week in the journal Science.
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