New Invisibility Cloak Closer to Working "Magic"

One element of the Harry Potter series is close to becoming a reality. A cloaking system has been developed that hides relatively big objects in visible light.

Harry Potter and Bilbo Baggins, take note: Scientists are a step closer to conquering the "magic" of invisibility.

Many earlier cloaking systems turned objects "invisible" only under wavelengths of light that the human eye can't see. Others could conceal only microscopic objects. (See "Two New Cloaking Devices Close In on True Invisibility.")

But the new system, developed at Massachusetts Institute of Technology and the Singapore-MIT Alliance for Research and Technology (SMART) Centre, works in visible light and can hide objects big enough to see with the naked eye.

The "cloak" is made from two pieces of calcite crystal—a cheap, easily obtained mineral—stuck together in a certain configuration.

Calcite is highly anisotropic, which means that light coming from one side will exit at a different angle than light entering from another side. By using two different pieces of calcite, the researchers were able to bend light around a solid object placed between the crystals.

"Under the assembly there is a wedge-shaped gap," said MIT's George Barbastathis, who helped develop the new system. "The idea is that whatever you put under this gap, it looks from the outside like it is not there." Read more