Undergrad solves major hurdle to invisibility cloak

By | August 17, 2011

An undergraduate at the University of St. Andrews in Scotland has overcome a major hurdle in the development of invisibility cloaks by envisioning an optical device that would allow the cloak to hide things
against CHANGING backgrounds. The Institute of Physics and German Physical Society's New Journal of Physics, published the study today, and the lead author, Janos Perczel, spoke with us about it from Hungary, via Skype,. But first — putting aside Harry Potter's cloak of invisibility for a moment, in real life, scientists have cloaked some palm-sized objects . . . but not especially well.€  …

… The sort of stuff you see in Harry Potter films has never been made yet. There have been experiments to test the theory but these experiments have always featured invisibility in some reduced form.

So far, cloaking only works when an object's against one single field of steady background wavelength, like a "blue screen." And even that's complicated. "Cloaking" conceals an object by bending light around it. Perczel says it's similar to putting a rock in a river, where the water bends around and covers the rock and makes it "disappear.. But just as water must speed up in order to hurry around the rock, bending light has required
accelerating the light. And super-speeded light flows too fast to allow a cloaking devices to adjust to changing backgrounds. In the new report, Perczel and colleagues offer a solution. They call it an invisibility sphere, and it buys enough time for the cloak to adjust to changing backgrounds by, well — what else? Their device slows down the normal speed of light. … It may be decades before this technology moves from theory to real world applications.€  But Perczel predicts that there will be plenty. …

via Janos Perczel — Invisibility Cloak (Extended Version)€ |€ How On Earth.

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