Light normally bounces off an object's surface making it visible to the human eye. But John Pendry and colleagues at Imperial College London, UK, have calculated that materials engineered to have abnormal optical properties, known as metamaterials, could make light pass around an object as so it appears as if it were not there at all.
Metamaterials are exotic composites made of electronic components such as wires and inductors that can be engineered to precisely control the way light travels through them.
Pendry's team has drawn up plans for a spherical metamaterial structure that would render an enclosed object invisible. "The theory tells us the material properties we need at each point," says team member David Smith, from Duke University in North Carolina, US. "The challenge is to match those theoretical requirements in the actual material, point-by-point."