Molding reflection from metamaterials based on magnetic surface plasmons

Abstract

We demonstrate a dramatically molded reflection of an electromagnetic (EM) wave from the magnetic metamaterial (MM) surface occurring near the magnetic surface plasmon (MSP) resonance. It is found that on one side of the source the reflected field nearly cancels the incoming field, giving rise to a shadowy region near the MM surface, while on the other side the reflected field considerably enhances the incoming field, resulting in a brightened region. Our analysis indicates that this effect arises from the coupling of the EM wave to the MSP band states which exhibit giant circulations going only in one direction due to the broken time reversal symmetry in MMs. Possible applications based on this effect are manifested in designing a robust one-way EM waveguide (OEMW), a ${90}^{\ifmmode^\circ\else\textdegree\fi{}}$ beam bender, and a beam splitter, which are shown to work even in deep subwavelength lateral scale ($~\ensuremath{\lambda}/10$), with $\ensuremath{\lambda}$ the wavelength of the propagating EM wave. Furthermore, the dependence of the OEMW on the channel width, the robustness of the OEMW against the defect and disorder, and the tunability of the working frequency by an external magnetic field are also studied.