Until recently, invisibility cloaks were the stuff of private laboratories or fantasy novels. Now, engineers from Duke University have taken advantage of 3D printing technology to fabricate an obscuring device that is inexpensive and can be put together in just a few hours. The device resembles a perforated disc, and algorithms determine where holes in the plastic patter should be placed in order to deflect microwave beams and create the cloak. Led by Yaroslav Urzhumov, the team published their results in the online journal, Optic Letters.
Any institution with a couple thousand dollars for a non-industry grade 3D printer can now make an invisibility cloak in less than a day. Yaroslav Urzhumov and his team created their own small device, using sterolithographic technology to lay down thin layers of polymer plastic to form a disc to deflect microwave beams. Opaque objects are placed in the center of the plate, and when microwaves are directed at the object through the side of the disc, it appears as though it can vanish into thin air. The way that the cloak is constructed eliminates the “shadow” that would be cast by the object, and suppresses the scattering of the light that would normally occur. The microwaves are are guided by the thin dielectric shell and re-radiated back into space on the opposite side of the cloak.
Researchers believe that the same technique could be used to construct even larger devices and be adjusted to manipulate visible light and infrared radiation. Computer simulations run by the engineers allow lead them to expect that the technology could produce similar results for objects several meters in diameter. Developments in nanotechnology would also be able to construct the cloaks out of glass or transparent polymers. With a computer template and 3D printer, it may soon be possible for anyone to hide their most prized possessions from surveillance.