Polarization bandpass filter based on one-dimensional photonic crystal heterostructures

Abstract

A new kind of polarization bandpass filters (P-BPFs), which fulfill the functions of high reflectivity for one polarization and high transmittance in the passband for the other, are proposed. The P-BPFs consist of a stack of two one-dimensional (1D) photonic crystals (PCs) that are referred to as 1D PC heterostructures. The essential function of P-BPFs is realized by making the first transmitted peak near the photonic bandgap edges of one PC coincide with that of the other PC. Based on this method, three kinds of filters have been designed and discussed in detail: an isotropic 1D PC single-polarization bandpass filter (SP-BPF) at oblique incidence with a narrow passband for TM polarization and a broadened stop band for TE polarization, an anisotropic 1D PC SP-BPF at normal incidence with a narrow passband for TE polarization and a broadened stop band for TM polarization, and an anisotropic 1D PC double-polarization bandpass filter (DP-BPF) at oblique incidence with a spectral separated narrow passband for both polarizations, respectively. The filters can be fabricated by a lot of coating methods and integrated easily with other photonic components.