Coupling light to a localized surface plasmon-polariton

We investigate the interaction of focused Gaussian and radially-polarized beams with a silver nanosphere, with emphasis on the coupling to localized surface plasmon-polaritons. We discuss the overall efficiency, including the effect of the entrance pupil and of absorption in the nanosphere, showing that a Gaussian beam performs better than a radially-polarized beam, when focused by an aplanatic system. We find that more than 50% of the photons in the incident beam can be reflected using realistic focusing parameters