Broadband optical cloak and illusion created by the low order active sources.

In present work, we demonstrate an optical cloak and illusion by appropriate design of a cluster of active sources. As pointed out by Vasquez and coworkers, the merit of such proposal with active controls is to overcome the drawback of narrow operating frequency and intrinsic loss inherent in the cloaking device made of metamaterials. Accordingly, the illusion device designed thuswise has a broadband operating frequency. By use of the rigorous multiple scattering theory, we have performed the simulations. It is shown that the active illusion device can be used as an beam rotator. In particular, we have shown that the active sources can even be reduced to dipole ones, which is expected to enable much easier experimental implementation of the cloaking and illusion effect.