Unveiling the invisible cloak

In an engineering breakthrough that is still to be seen,scientists have unveiled a blueprint to make an invisibility cloak, like the one worn by author J.K. Rowling's boy wizard Harry Potter.

Ateam of British and American researchers outlined the materials they say would be needed to make such a cloak in Thursday's online issue of the journal Science.

The Pentagon's Defense Advanced Research Projects Agency, or DARPA, sponsored the research because ofits potential military applications in thefield ofstealth technologies.

A cloak made of a "metamaterial" wouldn't reflect light or cast a shadow.

All light or other electromagnetic waves would be steered around the object, making it invisible, said study author David Smith, a professorof electrical and computer engineering at Duke University in Durham, N.C.

"The theory has only now become relevant because we can make metamaterials with the properties we are looking for," Smith said in a release.

No such cloak exists yet, but the first versions for masking radiation such as microwaves could be made in about 18 months, said study co-author John Pendry, a physicist at Imperial College London.

The cloak could also have applications for wireless communications, the team said.

"This is very interesting science and a very interesting idea and it is supported on a great mathematical and physical basis," Nader Engheta, a professor of electrical and systems engineering at the University of Pennsylvania, told the Associated Press.

Engheta was not involved in the study, but he is also working on metamaterials.