Nanotech Making Invisibility a reality

Presto! Now you see it, now you don't. No, it's not magic. Scientists at the University of Maryland have used nanotechnology — the science of matter on the atomic scale — to come up with a novel invisibility shield that can mask appearances in visible light. In essence, the optical cloaking device renders objects invisible by guiding light around the boundaries of the cloak. This development could lead to breakthroughs in computer chip designs. And the military has expressed interest in it as a potential way to elude radar detection. But alas, don't expect to be buying an invisibility cape soon, if ever. The cloak consists of a two-dimensional pattern of concentric rings of transparent plastic on a layer of gold film. The two materials have different refractive properties, which causes the cloak to bend any light that strikes it. When electron waves — known as plasmons — in the metal get disturbed by light, they appear to move in a straight line but actually are guided around the cloak. Nothing gets reflected back to the human eye, so the contents appear invisible. The scientific trick comes from how the material surface is structured, says Christopher Davis, a professor of electrical and computer engineering at Maryland's Clark School of Engineering. "We can show the waves coming into the surface being folded around a two-dimensional region and carried off to the other side," Davis said. "As a result, you can't see the cloaked region of the surface." This cloaking technology already has been used to build a powerful nanotech tool known as a super-lens microscope. It lets researchers see previously undetectable items on the nano-scale, at just 10 micrometers in diameter. Human hairs are 50 to 100 micrometers in diameter. Some day researchers could use such a microscope to capture crisp images of living cells, viruses and proteins. They might even see living DNA molecules, the genetic code for all life. Current electron microscopes must first kill such organisms before viewing them.