Low-loss plasmonic metamaterial waveguides

Surface plasmons (SPs), collective oscillation of electrons at metal/dielectric interface, carry electromagnetic energy in the form of surface-bound propagating wave, offering promising novel applications in various fields. Plasmonics, however, commonly suffers from large absorption losses (propagation length <;<;100 μm) limiting the potential of practical applications. In this work we developed a novel method to overcome this problem. By employing an anisotropic nanostructure we designed low-loss plasmonic metamaterial and waveguide structures. In overcoming plasmon losses we exploit the extra degree of freedom offered by the anisotropic metamaterials: the dielectric function is designed to be low-loss dielectric along the transverse direction and to be metallic along the longitudinal direction. By performing finite-difference time-domain (FDTD) analysis we demonstrate more than 10x improvement of propagation length (>1mm) and sub-wavelength scale confinement of light in the transverse direction.