Excitation of propagating surface plasmons by a periodic nanoparticle array: Trade-off between particle-induced near-field excitation and damping

Abstract

The excitation of propagating surface plasmons (SPs) on a silver-silica interface by an array of ellipsoidal silver nanoparticles is investigated using numerical simulations as a function of particle volume for three different nanoparticle aspect ratios with representative resonance frequencies. We find that while the SP amplitude depends sensitively on particle volume for each selected aspect ratio, the maximum SP amplitude obtained for the different particle shapes is remarkably similar. These observations are explained in terms of particle-mediated SP excitation, counteracted by a size dependent particle-induced damping. An analytical model is presented that quantitatively describes the observed trends in SP damping.