Directive emission based on one-dimensional metal heterostructures

We propose a method to realize directive emission using a layered metal heterostructure with around-zero average permittivity in the optical region. In the long-wavelength limit the heterostructure can be viewed as an epsilon-near-zero metamaterial. Our results show that when a transverse electric polarized source is placed in front of the heterostructure only the lights around the lines normal to the surfaces of the heterostructure can propagate through it. By exploiting constructive interference we can achieve good directivity and high transmission simultaneously. In addition, if the source is embedded in the heterostructure, the energy radiated by the source will be concentrated in a narrow cone.