Polarization-independent omnidirectional band gaps in heterostructures containing negative-index materials

Abstract

We proposed a type of heterostructure by combining two photonic crystals (PCs) consisting of alternating negative-index materials and positive-index materials layers. It is demonstrated by transfer matrix method that the proposed structure has a polarization-independent omnidirectional band gap (OBG), which is independent of the incident angle for both TE and TM polarizations. Compared to a single PC, the frequency range of the OBG in a heterostructure can be notably enlarged. Such a structure has potential applications in improving planar microcavities, optical fibers, and Fabry-Perot resonators, etc.