Fig. 1. Schematic illustration of SPPs propagating on a plasmonic cylindrical waveguide, km≡k∥,m=0⋅ρ^+mkϕϕ^+kz,mz^.

Fig. 2. Schematic illustration of the plasmonic cylindrical wire excited by light at one terminal for lower order modes. The light goes along y direction and the polarization is at 45° with the z axis which can be decomposed into x and z components.

Fig. 3. (a) Schematic illustration of the superposed m = 0 mode and m > 0 modes, which is similar to the vortex waves with l = 1,2,3. The red lines represent the maximum of the beats waves; the lighter lines indicate the beats behind the wire and the darker ones indicate the beats on the reader’s side. (b) The scheme of electric field distributions on plasmonic cylindrical nanowires excited by focusing light on one left terminals with polarization at + 45°(A^L), –45°(A^R) and 0°(A⁰) directions to z axis.

Fig. 4. The scheme of electric field distributions on plasmonic cylindrical nanowires excited by focused LCP (A^LCP) and RCP (A^RCP) light on left ends. The insets show the cross section at the wires at positions i and ii.