Design of multipolar plasmon excitations in silver nanoparticles

We report on the experimental observation of multipolar plasmon excitations in lithographically designed elongated silver particles. In contrast to spheres, where the extinction bands of the respective multipolar plasmons overlap considerably to form a broad spectrum, spectrally well-separated extinction bands corresponding to plasmons of multipolar order up to n=6 are found. The results agree well with numerical simulations based on the Green's Dyadic method. (C) 2000 American Institute of Physics. [S0003-6951(00)03847-X].