Phys. Rev. Lett. 102, 093901 (2009)

Invisibility shields that cause objects within them to vanish are now well-known. But Yun Lai and his colleagues of the Hong Kong University of Science and Technology in Clear Water Bay show how such a device might work to hide an object outside its confines.

In their theoretical scheme, the custom-made shield creates an 'anti-object' image that cancels out the light-scattering of the hidden object nearby, so that in optical terms the whole system is replaced by empty space.

The researchers provide a prescription for making anti-objects of arbitrary shape embedded in slabs of metamaterials, which are composed of building blocks that interact with light in unusual, tailor-made ways.