Zeroth-order complex dispersion relations of a cylindrical metallic nanowire have been solved out analytically with approximate methods. The analytical solutions are valid for the sections of the dispersion relations whose frequencies are close to the Surface Plasmon frequency. The back bending of the Surface PlasmonPolaritons(SPPs) can be well described by the analytical solutions, confirming that the back bending is originated from the metal Ohmic loss. The utility of the back bending point in the dispersion relation for the measurement of the metallic Ohmic loss has also been suggested.

No abstract

Benefiting from the induced image charge on film surface, the nanoparticle aggregating on metal exhibits interesting optical properties. In this work, a linear metal nanoparticle trimer on metal film system has been investigated to explore the novel optical phenomenon. Both the electric field and surface charge distributions demonstrate the light is focused on film greatly by the nanoparticles at two sides, which could be strongly modulated by the wavelength of incident light. And the influence of nanoparticle in middle on this light focusing ability has also been studied here, which is explained by the plasmon hybridization theory. Our finding about light focusing in nanoparticle aggregating on metal film not only enlarges the novel phenomenon of surface plasmon but also has great application prospect in the field of surface-enhanced spectra, surface catalysis, solar cells, water splitting, etc.

No abstract