Modulation of evanescent focus by localized surface plasmons waveguide.

In this paper, we present the modulation of a tightly focused evanescent field by a nano-plasmonic waveguide, which consists of two silver nanorods lying on the interface of two dielectric media. Linearly polarized and radially polarized illuminating beams are investigated under the influence of localized surface plasmons effect. It is demonstrated that different polarization components of the tightly focused evanescent field can be modulated accordingly. The results obtained from the finite difference time domain simulation show that super-resolved focal spot can be achieved using the nano-plasmonic waveguide structure.