Previous success in hiding objects has relied on bulky cloaking materials. Now researchers have developed a thin, form-fitting cloak that makes objects invisible to microwave radiation.
In a feat of physics worthy of Star Trek's Romulans, researchers have for the first time used a form-fitting cloak to render an object invisible from any direction. Sorry, Harry Potter, this is not magic.
The experiment, conducted using microwave radiation, eventually could help pave the way for more-effective ways to hide military aircraft from radar, the researchers say. If extended to visible light, the approach could lead to novel biomedical applications, as well as tiny switches for optical computing.
The feat is the latest in a decade-long effort to develop an ability to hide objects from view. Other researchers have been able to hide objects at microwave, infrared, and even visible-light wavelengths, and in two and three dimensions. But the cloaking materials have been bulky.
Indeed, it's a desire that traces its roots to H.G. Wells' "Invisible Man," notes Andrea Alu, an assistant professor of engineering at the University of Texas at Austin and a member of the research team reporting the results this week in the New Journal of Physics.
"We see objects by collecting whatever they radiate," he says, referring to the light that materials reflect or scatter.
One approach to cloaking is to change the behavior of electromagnetic radiation – radio or light, for instance – in ways that send the radiation around the object, rather than scattering some of it back at the detector trying to "see" the object.
Cloaks to accomplish this generally have been made from so-called metamaterials – materials engineered to display traits that aren't found in nature.
The team led by Jason Soric, in the department of Electrical and Computer Engineering at the University of Texas at Austin, designed its cloaking system using metamaterials as well. But instead of trying to bend radiation around the object so that none is scattered back to an observer, the researchers opted to use a cloak to change the properties of the radiation itself in ways that would cancel out the radiation scattered from an object.