Trapping of light by discontinuities of magnetization in a gyrotropic (meta) material

We show that an interface between two identical metal/dielectric plane-layered ferromagnetic (meta)materials with different directions of magnetization can support electromagnetic surface waves (SWs) of the visible or near-infrared band. We find that such an interface possesses so-called valve action allowing the propagation of SWs only within definite range of angles (including strictly unidirectional propagation), depending on the mutual orientation of magnetizations in the contacted media and filling factor of ferromagnetics in the metamaterial. Furthermore, these SWs can demonstrate unusual properties for conventional surface plasmon-polaritons, namely, a transverse electromagnetic (TEM) structure with zero angular momentum. We also reveal that in a plane-layered metal/dielectric metamaterial the weak optical gyrotropy can be considerably enhanced due to quasi-static LC resonance in this structure. (C) 2021 Optical Society of America