The Invisibility Cloak You've Been Waiting For
Everyone from Harry Potter to working physicists are fascinated with cloaking devices. In science fiction, capes can make kids invisible, but in real life, scientists have only been able to hide certain wavelengths of light — and so far those have been in the part of the spectrum we can’t see.
But now, researchers at at the University of Rochester have used simple, inexpensive, off-the-shelf components to hide objects in the visible spectrum of light. In other words, now you see it; now you don’t.
Such a system doesn’t work to fully hide you from the bad guys, but it could eliminate blind spots in vehicles or let surgeons see through their hands during delicate operations.
The basic idea behind cloaking is to manipulate light waves, forcing them around an object, like sending river water around a stone. Frequently, scientists use high-tech, exotic “meta-materials” that are expensive to develop, manipulate a part of the spectrum people can’t see anyway, or only work when one looks directly at the object. If you shift, you might see the object or the background shift around, giving away the trick.
John Howell, a professor of physics at the University of Rochester, and graduate student Joseph Choi combined four standard optical lenses in a way that keeps the object hidden, even as the viewer moves side to side.
The video shows the effect.
At the moment, the set up is not perfect. “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.
In essence, the cloaked region is shaped like a doughnut. But Choi and Howell have already built slightly more complicated designs that solve the problem.