One of the holy grail of sci-fi inventions has taken a step closer thanks to a 3D printed disc that makes objects invisible to microwaves. Scientists at Duke University have demonstrated an “invisibility cloak” which looks like a Frisbee with holes in it,
After demonstrating a proof of concept in the lab seven years ago, Yaroslav Urzhumov, assistant research professor in electrical and computer engineering at Duke Pratt School of Engineering, created the disc using algorithms to position the holes. When an object is placed in the center hole it is hidden from microwave beams aimed through the side of the disc, making it appear as though it isn’t there.
“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. “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.”
Although a cloak that only hides objects from microwaves doesn’t seem worthwhile Yuroslav expects that the technology could be used to create a cloak that wraps around an objects and would eventually be able to operate at higher visible light wavelengths.
The results of Yuroslav’s team’s research was published in a paper titled “Thin low-loss dielectric coatings for free-space cloaking” in the journal Optics Letters. The following video explains the science behind the cloaking device.