Magic carpets hide objects in plain sight
THE latest twist on invisibility cloaks won't hide Harry Potter in the middle of a room, but it might just let spies conceal microphones under the rug or the wallpaper. So called "carpet cloaks" are the first technology to succeed in hiding objects by deflecting light across a range of wavelengths. Two groups described different cloaks last week at the International Quantum Electronics Conference in Baltimore, Maryland. Invisibility cloaks work by deflecting light waves so the light that reaches the eye shows no trace of the hidden object. Conventional optical materials can't do this, but a dozen years ago John Pendry of Imperial College London showed it was possible to bend light around objects by building materials made of components smaller than the wavelength of the light. In theory, the principle will work across the electromagnetic spectrum, but early experiments with invisibility cloaks have been done at microwave frequencies, which have wavelengths in the ce...