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Forget virtual invisibility, this cloak is the real deal. Staffan Larsson
In the great quest to make all the coolest stuff from “Star Trek” come to life, scientists have found a way to create a real-world invisibility cloak that could actually be worn one day like a cloak, or even more creepy, like a second, disappearing skin.
A team of researchers at the US Department of Energy’s Lawrence Berkeley National Laboratory and the University of California at Berkeley have created what they call “an ultra-thin invisibility ‘skin’ cloak” that can be wrapped around a three-dimensional object to render it optically undetectable. Imagine being able to wrap an apple (or a 24th-century starship) in thin plastic wrap and hitting a switch, and the fruit (or U.S.S. Enterprise) suddenly disappears. That’s the basic concept.
There are other real invisibility cloak concepts out there, like the “Rochester Cloak” that can make an area invisible when you look through a set of lenses at it, and other engineered metamaterials (artificial nanostructures engineered with electromagnetic properties not found in nature) that hide objects tend to be like more bulky carpets than cloaks. But this new ultra-thin cloak, described in a paper to be published Friday in the journal Science, appears to be much more versatile than anything seen to date outside science fiction.

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“This is the first time a 3D object of arbitrary shape has been cloaked from visible light,” Xiang Zhang, director of the Berkeley National Lab’s Materials Sciences Division, said in a statement. “Our ultra-thin cloak now looks like a coat. It is easy to design and implement, and is potentially scalable for hiding macroscopic objects.”
Right now the cloak is microscopic in size and has been used to hide an object the size of a few irregularly shaped biological cells, but Zhang says the ultra-thin design should be able to scale up to much larger sizes far more easily than the earlier, carpet-like cloaks. So in theory, a large enough cloak would be able to make all our dreams and nightmares come true by concealing a dragon or an enemy warship.

It’s easiest to just presume this new skin cloak is powered by magic, but the science behind it is actually pretty close. The cloak is actually made up of blocks of gold nanoantennas and is significantly thinner than skin at just 80 nanometers. The cloak’s surface is meta-engineered to route light waves in such a way that the object is rendered invisible when the cloak’s activated. The scientists say the result is identical to light being reflected off a flat mirror.
Rather than enabling a new generation of high-tech pranksters or Starfleet defenses, the more likely applications for this technology include use in optical microscopes, speedy optical computers, security encryption and perhaps even in 3D displays.
Of course, this all depends on the scientists not losing their awesome new innovation, which also happens to be microscopic and invisible.

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