Optical negative index metamaterial based on hexagonal arrays of metallic meta-atoms with threefold rotational symmetry

摘要

Metamaterials consisting of two layers of hexagonal arrays of metallic meta-atoms with threefold rotational symmetry separated by a dielectric layer are investigated theoretically. The rotational symmetry of the constituent meta-atoms combined with that of the structure's lattice makes the studied metamaterial quasi-insensitive to the polarization of the incident light. By alternating small and large sized meta-atoms in the hexagonal arrays, the resulting structure allows both symmetric and antisymmetric hybridized plasmon modes in the same optical range of frequencies. When the resonances of the symmetric and antisymmetric modes are overlapping, the analyzed structures behave as a negative index material. (C) 2015 Optical Society of America