It's not like the Invisible Man in the movies. It's more like a mirage, where heat causes the bending of light rays and cloaks the road ahead behind an image of the sky. "We have built an artificial mirage that can hide something from would-be observers in any direction," said cloak designer David Schurig, a research associate in Duke University's electrical and computer engineering department.

Cloaking uses special materials to deflect radar or light or other waves around an object, like water flowing around a smooth rock in a stream. It differs from stealth technology, which does not make an aircraft invisible but reduces the cross-section available to radar, making it hard to track.

The cloaking of a cylinder from microwaves comes just five months after Schurig and colleagues published their theory that it should be possible. "We did this work very quickly ... and that led to a cloak that is not optimal. We know how to make a much better one."

Viewers can see things because objects scatter the light that strikes them, reflecting some of it back to the eye. "The cloak reduces both an object's reflection and its shadow, either of which would enable its detection."

"Since we do not have a perfect cloak at this point, there is some reflection and some shadow, meaning that the background would still be visible just darkened somewhat. ... We now just need to improve the performance of cloaking structures."

"Conceptually, the chance of adapting the concept to visible light is good", Schurig says "but From an engineering point of view it is very challenging."

Read more on the Duke University's web site