Invisibility cloak

Engineers working at Waltham, Massachusetts-based Fractal Antenna claim to have developed a device based on metamaterials that acts like an invisibility cloak for microwave radiation.

Built from belts of circuit boards festooned with fractal resonators, the device effectively 'slips' the microwaves around the cloaked object so the object is effectively invisible.

According to the company, the equipment and the fabrication techniques used to build the microwave cloak were much easier to work with than those that a visible light cloak would demand.

Nathan Cohen, chief executive officer at Fractal Antenna, said: 'While we had to show this by working at microwaves, physicists especially are excited by this result, in part because it means there is now a path and a recipe to reaping the benefits at visible light.'

But Cohen noted that the obstacles to making wideband-visible light cloaks with metamaterials are daunting. He said: 'You won’t see it soon. The technology to make the stuff doesn’t exist.'