Complementary media, zero index media and something in-between

In recent years the research of metamaterials has seen spectacular and explosive in both theoretical and experimental progress which enables exciting applications such as complementary media and zero refractive index media, with which I begin this thesis. Taking the limit of constitutive parameters of complementary slabs, a paradox is proposed that zero refractive index media can be viewed as a subset of complementary media, which is inconsistent with our knowledge. Studies on “realistic” complementary media by considering the absorption properly solve the paradox. We find a transition between “complementary-like” to “zero-index-like” and in the intermediate region, the system can absorb half of the incident energy even with vanishing small absorption coefficients. In addition, these conclusions can be extended to inhomogeneous systems. And similarly, abnormal gain effect is also expected. Under oblique illumination, Finite Difference Time Domain (FDTD) method is adopted to study the electromagnetic properties of the gain medium which is described by a four-level atomic system