Most invisibility cloaks require fairly exotic technology to work, such as fiber optics or light-altering metamaterials. That’s not very practical, especially since the illusion still tends to break when you move. The University of Rochester may have a far more realistic solution, however — it has developed a cloak that only needs run of the mill optical lenses to hide objects from view. The system really boils down to clever math. By positioning two pairs of lenses in the right order, researchers can bend light in a way that hides almost everything you put in the middle of this arrangement.
Inspired perhaps by Harry Potter’s invisibility cloak, scientists have recently developed several ways—some simple and some involving new technologies—to hide objects from view. The latest effort, developed at the University of Rochester, not only overcomes some of the limitations of previous devices, but it uses inexpensive, readily available materials in a novel configuration. “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,” said John Howell, a professor of physics at the University of Rochester. Forgoing the specialized components, Howell and graduate student Joseph Choi developed a combination of four standard lenses that keeps the object hidden as the viewer moves up to several degrees away from the optimal viewing position. “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,” said Choi, a PhD student at Rochester’s Institute of Optics.