Scientists Create Cloak of Partial Invisibility
By Ker Than
Staff Writer

Scientists have created a cloaking device that can reroute certain wavelengths of light, forcing them around objects like water flowing around boulders in a stream. To creatures or machines that see only in microwave light, the cloaked object would appear nearly invisible.

“The microwaves come in and are swept around the cloak and reconstructed on the other side while avoiding the interior region,” said study team member David Smith at Duke University’s Pratt School of Engineering. “So it looks as if they just passed through free space.”

The device [image] only works in the microwave range of light, so cloaked objects are still visible to humans. Also, it only works in two dimensions and only for microwaves moving in a plane. A three-dimensional invisibility cloak would hide an object completely.The microwave cloak is also slightly reflective and casts a partial shadow.

Despite these shortcomings, however, the new device is “a very good achievement,” said Ulf Leonhardt, a theorist at the University of St. Andrews in England who was not involved in the study.

“It’s surprising that it’s as simple as it is and that it works so well,” Leonhardt said in a related news article about the work in the journal Science.

The achievement, reported online today by the journal, comes five months after the same team published a study detailing the precise mathematical specifications a needed to build such a cloaking device.

The full story is here.
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