Creating an "invisibility" cloak could one day be cheap enough to do at home.
3D printing -- using a nozzle guided by software which lays down successive thin layers of a material to create three-dimensional objects -- has become increasingly popular. The technique has found applications in architecture and the creation of housing and even a moonbase, Kickstarter is awash with home-based printing projects trying to get off the ground, and health professionals have found it useful for prosthetics.
Duke University researchers, led by Yaroslav Urzhumov, assistant research professor in electrical and computer engineering at Duke’s Pratt School of Engineering, have used this process to create a cloaking device which could be inexpensive enough to one day be manufactured at home.
"I would argue that essentially anyone who can spend a couple thousand dollars on a non-industry grade 3-D printer can literally make a plastic cloak overnight," Urzhumov says.
At Duke, the team created an inexpensive invisibility cloak -- which looks something like a Frisbee -- in less than seven hours.
The donut-shaped cloak can have an opaque object placed inside it, and when microwave beams are aimed at the object, the cloak's properties make the object appear not to exist. The design eliminates shadow and suppresses light scattering from the object. In short, if an object is highly reflective, it is made invisible.
Microwave beams are diverted from the cloak, but the researchers feel this can be improved upon by including higher wavelengths -- including light that humans can see.
"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."
In theory, this technique could be applied to larger objects, and a cloaking device as thin as one inch thick could be wrapped around items to disguise them.
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