Aug 11, 2008 7:40 pm US/Pacific
Cal Scientists Get Closer To 'Invisibility' Cloak
BERKELEY (CBS 5 / AP / BCN) ―
Scientists at the University of California, Berkeley said Monday they were a step closer to developing materials that could render people and objects invisible to the human eye.
Researchers have demonstrated for the first time they were able to cloak three-dimensional objects using artificially engineered materials that redirect light around the objects. Previously, they only have been able to cloak very thin two-dimensional objects.
The findings by a research team led by Xiang Zhang are to be released later this week in the journals Nature and Science.
"We are excited because this is a building block for the future," said researcher Guy Bartal. However, he added that developing an invisibility cloak is "a very big challenge" and "will take a lot of energy and time."
Speaking at a news conference at Etcheverry Hall on campus, Bartal and other researchers said the development of an invisibility cloak, a popular subject in science fiction and Harry Potter novels, is probably still years away.
But the new work moves scientists a step closer to hiding people and objects from visible light, which could have broad applications, including military ones.
People can see objects because they scatter the light that strikes them, reflecting some of it back to the eye. Cloaking uses materials, known as metamaterials, to deflect radar, light or other waves around an object, like water flowing around a smooth rock in a stream.
Metamaterials are mixtures of metal and circuit board materials such as ceramic, Teflon or fiber composite. They are designed to bend visible light in a way that ordinary materials don't. Scientists are trying to use them to bend light around objects so they don't create reflections or shadows.
"Obviously, there are some military applications" said Jason Valentine, a UC-Berkeley graduate student participating in the research. "The military is interested in metamaterials because it's a new material and has a flexible platform."
It differs from stealth technology, which does not make an aircraft invisible but reduces the cross-section available to radar, making it hard to track.
Valentine said it's difficult to predict how long it will take to finish developing an invisibility cloak because the field of metamaterials is very new — only about 10 years old.
The research was funded in part by the U.S. Army Research Office and the National Science Foundation's Nano-Scale Science and Engineering Center.
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