Nonreciprocal omnidirectional band gap of one-dimensional magnetized ferrite photonic crystals with disorder

Abstract

Based on the transfer matrix method (TMM), the nonreciprocal omnidirectional band gaps (OBGs) of magnetized ferrite photonic crystals (MFPCs), consisting of the Yttrium iron garnet ferrite and general dielectric, are investigated. Herein, a disordered MFPC is modeled by rendering the thicknesses of the general dielectric in the Gauss distribution. With the introduction of D, t, and H0 to quantitatively describe the disorder degree, the average thicknesses of the general dielectric layers and the external magnetic field, the three parameters are adjusted for multifarious values. It is shown that the disorder effects (DEs) lead the OBGs to the pattern, that the widths primarily expand and then narrow down with the increasing D. Thereinto, the OBG of D = 0.1 attains the maximum. Also, on top of D = 0.2, the OBGs for the negative fully cover the OBGs for the positive. The OBGs are sensitive to the switches in t and H0 that the ranges vary irregularly with these two variables. For t = 0.2, the OBGs exhibit excellent nonreciprocity, with no overlapping bands in the OBGs for the positive and negative propagation. The results help assume the possible DEs on the OBGs of the MFPCs and give practical advice on the design of filters.