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Invisibility cloak within our grasp
HARRY Potter fans take note: scientists in the US have finally come up with a workable design for an invisibility cloak.Physicists figured out the complex mathematical equations for making objects invisible by bending light around them last year. Now a group of engineers at Purdue University in Indiana has used those calculations to design a relatively simple device that may one day be able to make objects as big as a plane disappear. The design calls for tiny metal needles to be fitted into a cone like a hairbrush, at angles and lengths that would force light to pass around it. This would make everything inside the cone appear to vanish because the light would no longer reflect off it. "It looks pretty much like fiction, I do realise, but it's completely in agreement with the laws of physics," said lead researcher Vladimir Shalaev, a professor of electrical and computer engineering at Purdue. "Ideally, if we make it real it would work exactly like Harry Potter's invisibility cloak," he said. "It's not going to be heavy because there's going to be very little metal in it." The still-theoretical design will be published this month in the journal Nature Photonics. Prof Shaleav said he needed to secure The major limitation is that the current design can only bend the light of a single wave-length at a time, and does not work with the entire frequency range of the visible spectrum. "How to create a design that works for all colours of visible light at the same time will be a big technical challenge, but we believe it's possible," Prof Shalaev said. "In principal [sic] it's do-able." Even blocking a single frequency could lead to useful applications, Prof Shaleav said. The cloak could shield soldiers from night-vision goggles which use only one wavelength of light. It could also be used to hide objects from "laser designators" used by the military to illuminate a target, he said. Posted by: zazz 2007-04-07 |
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