One-way EM waveguide formed at the interface between metal and uniformly magnetized two-dimensional photonic crystal fabricated from magneto-optic material

We have demonstrated numerically that a waveguide formed by the interface of a metal and uniformly magnetized twodimensional photonic crystal fabricated from a transparent dielectric magneto-optic (MO) material possesses a one-way frequency range where only a forward propagating surface plasmon polariton (SPP) mode is allowed to propagate. In contrast to an analogous waveguide proposed by Yu 1 the non-reciprocity at the interface is introduced by the MO properties of the photonic crystal material and not by applying an unrealistically high static magnetic field (up to 1 T) on metal described by free-electron Drude form of the dielectric function. The considered magnetic material is Bismuth Iron Garnet (BIG, Bi 3 Fe 5 O 12 ), a ferrimagnetic oxide which may be easily magnetically saturated by fields of the order of tens of mT. Therefore, this configuration allows to achieve sizable one-way bandwidth by using significantly smaller values of the external magnetic field which makes such a waveguide favorable for design of diode-like elements in optical integrated circuits. By using a novel MO aperiodic Fourier Modal Method (MO a-FMM) to calculate the band structure of this magneto-plasmonic photonic crystal waveguide we have proven the existence of one-way SPP bands within the optical wavelength.To investigate transport properties of the structures within this frequency range we have implemented two finite-difference time-domain (FDTD) methods, namely ADE 2 and that based on Z-transforms 3 that allow calculating the propagation of EM waves through media with full tensorial magneto-optic permittivity. We provide numerical evidence confirming suppression of disorder-induced backscattering in the one-way waveguide.