LONDON, England - June 8, 2010 - The "invisibility cloaks" being made in labs today can hide objects when viewed from a wide range of directions and in visible light - both considered implausible developments when the first working invisibility cloak was demonstrated just four years ago. But the technology that makes objects vanish looks set to be more useful for the safety of offshore structures and for unlocking cosmological secrets than for would-be Harry Potter impersonators.
In 2006, John Pendry’s team at Imperial College London made the news with a design for a cloak that could steer light around an object to render it invisible. Within months a team led by David Smith of Duke University in Durham, North Carolina, had built such a device using exotic "metamaterials" - materials with unusual electromagnetic properties that are not found in nature.
But that first cloak could only hide two-dimensional objects viewed from specific directions - and only if they were "viewed" using one particular microwave frequency. Producing a cloak to hide objects from visible light, which has a wavelength several orders of magnitude smaller than microwaves - let alone cloaking objects when viewed from any direction – seemed a more remote possibility.
Just four years later that's no longer the case. "While full cloaking has not been achieved, it shows promises in the right direction," says Ulf Leonhardt at the University of St Andrews, UK.
