Purdue engineers create 'optical cloaking' design for invisibility
10 Apr '07
2 min read
Optical Cloaking device
Researchers using nanotechnology have taken a step toward creating an "optical cloaking" device that could render objects invisible by guiding light around anything placed inside this "cloak."
The Purdue University engineers, following mathematical guidelines devised in 2006 by physicists in the United Kingdom, have created a theoretical design that uses an array of tiny needles radiating outward from a central spoke.
The design, which resembles a round hairbrush, would bend light around the object being cloaked. Background objects would be visible but not the object surrounded by the cylindrical array of nano-needles, said Vladimir Shalaev, Purdue's Robert and Anne Burnett Professor of Electrical and Computer Engineering.
The design does, however, have a major limitation: It works only for any single wavelength, and not for the entire frequency range of the visible spectrum, Shalaev said.
"But this is a first design step toward creating an optical cloaking device that might work for all wavelengths of visible light," he said.
Leonhardt says in his commentary that creating a cloak for rendering total invisibility in the entire visible spectrum would require "further advances in optical metamaterials, new combinations of nanotechnology with highly abstract ideas ..."
The optical cloaking research is an indirect spinoff of research in Shalaev's lab that has been funded by the U.S. Army Research Office to develop metamaterials.
In previous work, Shalaev's team created a metamaterial that has a "negative index of refraction" in the wavelength of light used for telecommunications, a step that could lead to better communications and imaging technologies.
More recently, the researchers moved the wavelength for a negative refractive index material to the visible range.
marketing@alchempro.com
