Magnetically Tunable Unidirectional Electromagnetic Devices Based on Magnetic Surface Plasmon

Plasmonic metamaterials are composite, artificial materials, consisting of metallic resonant building blocks designed with state-of-the-art configurations. Many exotic phenomena not occurring in nature such as negative refraction (Burgos et al., 2010; Dolling et al., 2006; Lezec et al., 2007; Liu et al., 2008; Pendry, 2000; Shalaev, 2007; Shelby et al., 2001; Smith et al., 2000; Valentine et al., 2008; Veselago, 1968; Zhang et al., 2005), subwavelength imaging (Fang et al., 2005; Liu et al., 2007; Pendry, 2000; Taubner et al., 2006), cloaking (Ergin et al., 2010; Leonhardt, 2006; Lai et al., 2009; Li et al., 2008; Liu et al., 2009; Pendry et al, 2006; Schurig et al., 2006), and so on can be observed in the systems made of such materials. A particular characteristic of the system is the excitation of surface plasmon polaritons (SPPs) (Barnes et al., 2003; Giannini et al., 2010; Noginov et al., 2008; Zayats et al., 2005), which originates from the coupling of the electromagnetic (EM) wave to the free electron oscillation in metallic surface. The EM waveguiding mediated by the SPPs has gained more and more attention from theorists, experimentalists, and engineers due to its promising applications in integrated optical circuit, optical storage, biosensing, and even medical therapy (Engheta, 2007; Ozbay, 2006; Zia et al., 2006). A series of plasmonic components have been proposed and realized, such as plasmonic waveguides, beam splitter, sharp bends and so on. Very recently, based on the excitation of the SPPs the plasmonic Luneburg and Eaton lens are even realized experimentally (Zentgraf, 2011).