Contents I. Introduction
One-way electromagnetic (EM) modes are such modes that they are allowed to propagate in only one direction, and because of the absence of a back-propagating mode in the system, they are immune to backscattering at imperfections. One-way EM modes were first proposed as analogues of quantum Hall edge states in photonic crystals (PhCs) [1], [2]. These one-way modes can be sustained by the edges of certain two-dimensional (2D) PhCs made of magnetic-optical (MO) materials [1]–[5], whose time-reversal symmetry is broken by applied dc magnetic field. Other type of one-way surface wave, i.e., one-way surface magnetoplasmon (SMP) [6], was also proposed later [7], [8]. One-way SMPs can be supported by bulk plasmonic materials in optical [7] or terahertz regimes [9], [10]. In microwave domain, one-way SMPs can be supported by yttrium-iron-garnet (YIG) materials [11]. Recently, we reported a one-way EM mode which is not surface wave in the microwave regime [12]. Such one-way mode is guided by the mechanism of total internal reflection (TIR) in the system consisting of a dielectric layer sandwiched between magnetized YIG and metal.
