Terahertz filter based on refractive properties of metallic photonic crystal.

We propose a new type of pass-band filter, in this case designed to operate in the terahertz frequency regime, possessing two separate passbands utilizing the distinction between positive and negative refraction in a photonic crystal prism. The prism is formed from a two-dimensional hexagonal arrangement of metallic rods. In order to understand the operation of the filter we both consider the photonic bandstructure of the associated infinite photonic structure and carry out simulations of the refraction properties of the prism using finite-difference time-domain software.