Hiding inside an arbitrarily shaped metal pit using homogeneous metamaterials

Abstract

Even though its origins were at science fiction and fantasy, invisibility cloaks are a reality. However, realization of invisibility cloaks requires material characteristics that are hardly available in nature. Fortunately, artificial designer materials known as metamaterials provide unprecedented freedom in synthesizing materials with flexible electromagnetic properties. In this paper, by introducing a new transformation that can warp the space to deflect light inside an arbitrarily shaped metal pit filled with diagonal metamaterial (i.e. a metamaterial with permittivity and permeability tensors that are diagonal), we show that objects can be effectively hidden from view. The implementation requires a single homogeneous metamaterial and thus much different from the existing alternative approaches that require multiple homogeneous metamaterials. To show the utility of the proposed method, using detailed numerical simulations we show two distinct cloaks that can conceal the objects by the same diagonal metamaterial medium and analyze the impact of the losses in the medium on this method.

Acknowledgement

The work of W. Zhu and M. Premaratne was supported by the Australian Research Council, through its Discovery Grant scheme under grant DP110100713. Y. Huang also gratefully acknowledges Research Fund for the Doctoral Program of Higher Education of China (No. 20110185110014) and the Fundamental Research Funds for the Central Universities (No. E022050205).