Earlier this year the team of Professor Sir John Pendry announced a theory for the creation of an invisibility cloak, using "metamaterials" - materials modified at a nano-scale to change their structure - to allow light to flow around an object like water does. A team at Duke University have now built a working prototype based on his team's theory.
In May Pendry had a paper in the journal Science which provided a mathematical verfication of the technique to be used. Pendry, along with David Smith and David Schurig at Duke, had been testing metamaterials for the project. They have now achieved a breakthrough, forming a two-dimensional cloak which allows microwaves to flow around an object rather than scattering. Measurements taken on the prototype indicate that it is a success, with the waves separating and then reforming after flowing around the it. The team are perfecting the two-dimensional technique and hope to develop a three-dimensional microwave cloak in the future.
Metamaterials used to build the cloak are fashioned into concentric two-dimensional rings, which interact with electromagnetic waves to pass them around the object. The cloak is thought to be one of the most complex metamaterial structures ever made, as it has a unique circular geometry and it's electromagnetic properties vary across its surface.