Engineers have already conquered flying and put a man on the moon. Now, the world may be one step closer to another coveted superpower: invisibility.
Ordinarily, light rays hit an object, bounce off and then are captured by the eye. Researchers at the university have developed the world’s first “invisibility cloak,” which when placed over an object, bends the light around it instead.
And the eye is none the wiser.
The device is still in its early stages of development and is only effective with two-dimensional objects, but researchers say they are very interested in continuing to work in the area of invisibility in the future.
The device, made of “metamaterials” – gold and special plastics – demonstrates negative light refraction, a term to describe when light rays bend. An example of this phenomenon can be seen when a stick is dipped into water and appears to be bent, said Christopher Davis, professor of electrical and computer engineering.
The metamaterials are electromagnetic, and have unusual properties that allow light to bend around them. They consist of concentric rings of polymethyl methacrylate (a plastic) on top of a thin film of gold.
Although previous invisibility cloaks have been created using microwave rays – short electromagnetic waves of radiation – instead of light rays, this is the first time that a cloaking device has been made for the visible spectrum.
The researchers, led by Igor Smolyaninov, a visiting research scientist in the engineering department, believe that a practical, three-dimensional cloaking device is possible in the future. However, “cloaks are never going to be perfect,” said Smolyaninov.
The researchers expressed hope that ideas from their project could be used in the future by the military for stealth vehicles or airplanes.
The researchers emphasized that their studies in invisibility are in the very early stages. Their paper outlining the project was published to arXiv, a website for scientists to post their work and get feedback, but has yet to be published in any kind of scientific journal.
“This has been a hot subject in the past few years,” said Davis. “It’s the sexiest thing we can talk about right now.”
The cloak team, which was funded by a grant from the National Science Foundation, also consisted of Yu-Ju Hung, an engineering graduate student.
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