Design and simulation of nana-optical beam generators based on zero-index materials

We present design and computational analysis of near-zero-index (NZI) structures that act as nano-optical beam generators when excited internally by isotropic sources. The designed structures have homogenized shell geometries with various modifications to generate asymmetric tridirectional, bidirectional, and unidirectional beams, in addition to symmetric ones. NZI properties make it possible to generate beams from planar surfaces, while numerical results show that the behavior of a shell is very sensitive to the geometric parameters and the nature of the NZI, i.e., permittivity and permeability values. We show that, by using asymmetric cavities and pyramidal textures, it is possible to generate asymmetric beams with suitable choices of dimensions and material properties