The new cloak with the bump, left, and the prototype, right.
(Credit: Duke University)That cloaking device we've been dreaming of appears to be one step closer to actual cloakdom, so start pondering the mischievous possibilities.
Scientists from Duke University have improved on their earlier efforts at producing an invisibility cloak, coming up with a new type of device they say is significantly more sophisticated at cloaking an object (and eventually a person?) from visible light.
The device is made from a light-bending composite material that can detour electromagnetic waves around an object and reconnect them on the other side. That creates an effect similar to a distant mirage you'd see hovering above a road on a hot day.
In Duke's latest experiments, a beam of microwaves aimed through the cloaking device at a "bump" on a flat mirror surface bounced off the surface at the same angle, as if the bump wasn't there. Additionally, the device prevented the formation of scattered beams that would normally be expected from such a perturbation. (The team details its findings in far more technical terms than I ever could in the latest issue of Science magazine.)
... Read moreScientists say they are a step closer to developing materials that will render people and other objects invisible.
Researchers say they can redirect light around 3D objects using metamaterials--artificially engineered structures created at a nano scale that contain optical properties not found in nature, according to an Associated Press report.
People see objects as a result of the light reflecting or scattering off them. This new mixture of materials has "negative refractive" properties that keep light from being absorbed or reflected by the object, allowing only the light from behind the object to be seen. Essentially, the material bends visible light in a way that eliminates the creation of reflections or shadows in much the way water flows around a stone.
The findings, to be released later this week in Nature and Science, were made by scientists at the University of California, Berkeley, led by Xiang Zhang. The research, which was funded in part by the U.S. Army Research Office and the National Science Foundation's Nano-Scale Science and Engineering Center, could have broad applications, including for the military.
But the materials work in limited wavelengths, so they won't be used to hide buildings from satellites, said Jason Valentine, who is a co-author of one of the papers.
"We are not actually cloaking anything," Valentine told Reuters. While the Harry Potter series of books and films has made the idea of a personal "invisibility cloak" popular, he says, "I don't think we have to worry about invisible people walking around any time soon. To be honest, we are just at the beginning of doing anything like that."
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