 | The cloak's concentric gold rings can steer light waves travelling along a surface around an object and straight on again as if it was not there |
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The
world's first true invisibility cloak - a device able to hide an object in
the visible spectrum - has been created by physicists in the US. But don't
expect it to compete with stage magic tricks. So far it only works in two
dimensions and on a tiny scale. The new cloak, which is just 10 micrometres in
diameter, guides rays of light around an object inside and releases them on the
other side. The light waves appear to have moved in a straight line, so the
cloak - and any object inside - appear invisible.
The cloak was built by a team led by Igor Smolyaninov at the University of
Maryland, and borrows some ideas from the first theoretical design for an
invisibility cloak, published by Vladimir Shalaev from Purdue University, West
Lafayette, Indiana, US, earlier this year. Their breakthrough comes just a year
after US and British physicists created an invisibility cloak that worked in the
microwave region of the electromagnetic spectrum. At that time, a visible light
cloak was thought to be years away because of the much shorter wavelengths
produced in the visible spectrum.