Characteristic properties of electromagnetic wave interaction with uniaxial absorbing metamaterials: A case of the near-zero axial parameter

An exact solution of the boundary electrodynamic problem for a thin layer of uniaxial absorbing metamaterial characterized by the effective permittivity (permeability) tensor with near-zero values of the axial component is investigated. The parameters of optical anisotropy, absorption, and geometry of the problem are determined when the layer exhibits plane electromagnetic wave reflection and transmission that are selective with respect to one or several incident angle ranges. The numerical analysis shows that even small deviations from ideal conditions (losses, non-zero values of the axial component, nonorthogonality of the optical axis to the layer boundaries) can lead to remarkable changes of the metamaterial properties. The low level of losses, required for applications of the material (spatial filtering of the radiation, etc.), seems to be unattainable nowadays for passive metamaterials, so the realization of the concept can be concerned with active metamaterials.