Can you 3-D print an invisibility cloak?

Duke University engineers announced that its microwave frequency cloaking technology first demonstrated in 2006 can be made using 3D printing. What’s more, a team lead by Yaroslav Urzhumov, assistant research professor in electrical and computer engineering at Duke’s Pratt School of Engineering, say the same technique lead to visible light cloaks in the not so distant future.

“We believe this approach is a way towards optical cloaking, including visible and infrared,” Urzhumov said. “And nanotechnology is available to make these cloaks from transparent polymers or glass. The properties of transparent polymers and glasses are not that different from what we have in our polymer at microwave frequencies.”

For now, the small, 3D-printed version of the device only shields opaque objects placed in the center of the disc-shaped structure from microwave frequencies. Holes through the edge of the disc, whose shape, size and location are determined by algorithms, deflect the beams.

“The design of the cloak eliminates the ‘shadow’ that would be cast, and suppresses the scattering from the object that would be expected,” Urzhumov said. “In effect, the bright, highly reflective object, like a metal cylinder, is made invisible. The microwaves are carefully guided by a thin dielectric shell and then re-radiated back into free space on the shadow side of the cloak.”

Plans include scaling the cloak up to hide larger objects. Urzhumov says simulations suggest that a similar one-inc polymer-based cloaking layer could camouflage object as big as several meters in diameter.
www.pratt.duke.edu