http://www.sina.com.cn 2008年11月05日 10:14
Scientists closer to developing invisibility cloak
WASHINGTON—Scientists say they are a step closer to developing materials that could render people and objects invisible.
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 scientists at the University of California, Berkeley, led by Xiang Zhang, are to be released later this week in the journals Nature and Science.
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.
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.(AP)