Scientists Make Simple Objects 'Invisible'

Harry Potter's invisibility cloak no longer belongs solely to the world of fantasy. Scientists from the University of Rochester have brought the famous cape to real life, in a sense, after developing new technologies that can hide simple objects from view.

The novel technology not only overcomes some of the limitations of previous devices, but it uses simple, inexpensive, off-the-shelf components to hide objects in the visible spectrum of light.

"There've been many high tech approaches to cloaking and the basic idea behind these is to take light and have it pass around something as if it isn't there, often using high-tech or exotic materials," John Howell, a professor of physics at the University of Rochester, said in a statement.

"This is the first device that we know of that can do three-dimensional, continuously multidirectional cloaking, which works for transmitting rays in the visible spectrum," added graduate student Joseph Choi, who was involved in the research.

The basic idea behind cloaking, according to the study, published in the journal Optics Express, is to manipulate light waves to force them around an object. This design works fine when you look at an object straight on, but frequently what happens is that if you move your viewpoint even slightly the object becomes visible.

So Howell and Choi combined four standard optical lenses in a way that keeps the object hidden, even as the viewer moves from side-to-side.

While the new cloak works for the whole visible spectrum of light, and can be applied to fairly large objects, it's not a perfect design.

"This cloak bends light and sends it through the center of the device, so the on-axis region cannot be blocked or cloaked," said Choi. Meaning, the cloaked region is shaped like a doughnut. But he and Howell have already built slightly more complicated designs that solve the problem.

[Credit: UniversityRochester]