Modified nonreciprocal waveguide formed at the interface between plasmonic metal and uniformly magnetized two-dimensional photonic crystal fabricated from magneto-optic material

ABSTRACT We have demonstrated numerically that the interface of a metal and uniformly magnetized two-dimensional photonic crystal fabricated from a transparent dielectric magneto-optic (MO) material possesses a one-way frequency range where only a forward propagating surface plasm on polariton (SPP) mode is allowed to propagate. The nonreciprocity at the interface is introduced by the MO properties of the photonic crystal that is fabricated fr om 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 than an analogous waveguide proposed by Yu 1 which makes such a waveguide favorable for design of diode-like elements in optical integrated circuits. By using simple an alytical model we have determined one-way frequency range which is consistent with the results obtained previously by using a MO aperiodic Fourier Modal Method (MO a-FMM). To investigate tr ansport properties of the structures within this frequency range we have implemented finite-difference time-domain(FDTD) method, that allows calculating the propagation of EM waves through media with full tensorial magneto-optic permittivity. We examined the unidirectiona l transport properties of the proposed one-way waveguide and studied how the nonreciprocity depends on boundary conditions, for instance, by placing a perfect conducting mirror at the end of one-way waveguide. Keywords: one-way EM waveguide, magnetooptic photonic crystal, surface plasmon polariton, nonreciprocity