Plasmonic nanoantennas: Angular scattering properties of multipole resonances in noble metal nanorods

The scattering properties of multipole plasmon resonances sustained by silver and gold nanorods (NRs) are investigated using classical electrodynamics DDA (discrete dipole approximation) simulations. The angular distribution of the scattered light is examined as a function of the multipole order, NR length, noble metal nature, and dielectric environment. For a given multipole order, the dependence of the differential scattering cross section on the different variables is rationalized in terms of two different contributions to the differential scattering cross sections: the resonant wavelength and the Mueller matrix element S(11). It was found that the magnitude of S(11) for a given multipole order is mainly determined by its quantum scattering yield. By comparing the scattering patterns of finite cylinders with the radiation scattered by a point light source, it was possible to characterize and gain physical insight on the different resonance modes.