Fig. 1.

Plasmonic nanoantenna concept. (a) Collective oscillations of conduction electrons in metal nanoparticle excited by propagating light create regions of positive and negative surface charge, resulting in the generation of secondary dipole fields around the particle. (b) Optical powerflow around a noble-metal nanosphere at the frequency of its dipole LSP resonance shows strong deflection of incident light towards the particle. Hereafter, the arrows point into the direction of the local powerflow; the length of each arrow is proportional to the local value of the Poynting vector amplitude.