Optical near-field of multipolar plasmons of rod-shaped gold nanoparticles

We report on near-field measurements and calculations of the optical intensity close to rod-shaped gold nanoparticles excited at a multipolar plasmon resonance. Our results reveal a distinct optical near-field pattern and show that multipolar plasmon excitation of single nanoparticles can be imaged in the near-field. The observed optical neat-field patterns can be understood in a model of standing plasmon waves.