Duke Researchers Create 3D Printed 'Invisibility Cloak'

The idea of a magical item that bestows invisibility on the user is older than characters famous for using such cool toys, such as Harry Potter or Bilbo Baggins. The notion of invisibility still captures the imagination, though, to be honest, I suspect invisibility would be put to less than benevolent uses by most people.

While the object in question is neither a cloak, nor does it provide actual invisibility, researchers at Duke University’s Pratt School of Engineering still refer to their creation by the pop culture reference. The object in question is actually a circle with holes of seemingly random shapes and sizes punched in it, surrounding a larger circular hole in the center.

According to the research team, the size, shape and location of each hole has been determined with utmost precision thanks to an algorithm. The idea is the smaller holes hide an object placed in the center hole from microwave beams that target the “cloak,” making said object technically invisible.

"The design of the cloak eliminates the 'shadow' that would be cast, and suppresses the scattering from the object that would be expected," said Yaroslav Urzhumov, assistant research professor in electrical and computer engineering. "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."

It might not seem like redirecting microwaves is all that useful, but Urzhumov claims the research team should eventually be able to produce a cloak that actually affects visible light. An inch-thick polymer-based cloaking layer would be all that is required to finally achieve true invisibility.

Duke researchers have been tinkering with this idea for a few years now, but have just begun to use 3D printing to make the creation process quicker and easier. According to the scientists, anyone with a 3D printer could replicate the results of their experiment and build an invisibility cloak at home. The team's findings have been published in a paper titled "Thin low-loss dielectric coatings for free-space cloaking" in Optics Letters.

Below you’ll find one member of the team discussing invisibility.

Source: Duke University