Physics News

Researchers have created a new type of invisibility cloak that is simpler than previous designs and works for all colors of the visible spectrum, making it possible to cloak larger objects than before and possibly leading to practical applications in "transformation optics."Whereas previous cloaking designs have used exotic "metamaterials," which require complex nanofabrication, the new design is a far simpler device based on a "tapered optical waveguide," said Vladimir Shalaev, Purdue University's Robert and Anne Burnett Professor of Electrical and Computer Engineering.Waveguides represent established technology - including fiber optics - used in communications and other commercial applications.The research team used their specially tapered waveguide to cloak an area 100 times larger than the wavelengths of light shined by a laser into the device, an unprecedented achievement.

"metamaterials," which require complex nanofabrication, the new design is a far simpler device based on a "tapered optical waveguide," said Vladimir Shalaev, Purdue University's Robert and Anne Burnett Professor of Electrical and Computer Engineering.
"All previous attempts at optical cloaking have involved very complicated nanofabrication of metamaterials containing many elements, which makes it very difficult to cloak large objects," Shalaev said. "Here, we showed that if a waveguide is tapered properly it acts like a sophisticated nanostructured material."
"Instead of being reflected as normally would happen, the light flows around the object and shows up on the other side, like water flowing around a stone," Shalaev said.