We develop a general theoretical approach to describing the interaction of metamaterials with optical beams. The metamaterials are allowed to be anisotropic, chiral, noncentrosymmetric, and spatially dispersive. Unlike plane waves, beams can change their field distributions upon interaction with metamaterials, which can reveal new optical effects. Our method is based on a vector form of the angular spectrum representation and a technique to calculate the wave parameters for all required directions of wave propagation. Applying the method to various metamaterial designs, we discover a new optical phenomenon: the conversion of light polarization by spatial dispersion. Because of this phenomenon, the refractive index and impedance cannot be introduced for many metamaterial designs. In such cases, we propose an alternative approach to treating the beam–metamaterial interaction. This work takes a step forward in describing optical metamaterials by moving from unphysical plane waves to realistic optical beams.
- metamaterials angular spectrum
- polarization modes
- spatial dispersion