Unidirectional light propagation characteristics through two-dimensional metallic photonic crystal composite structures

Abstract

Unidirectional light transmission through composite structures, consisting of a square lattice of square metals with different sizes, is studied by the finite-difference time-domain method. Through adding two metallic slices into the lateral boundaries of the composite structures, the lateral light energy leak is avoided and unidirectional light propagations towards two opposite directions are obtained within two separate frequency regions based on the directional band gaps. Through the design of arranging metallic rods at the interface of two photonic crystals, the unidirectional light propagation, based on the different refractive and reflective behaviors at the frequencies within the pass bands, is also obtained.