Nonradiative limitations to plasmon propagation in chains of metallic nanoparticles
Résumé
We investigate the collective plasmonic modes in a chain of metallic nanoparticles that are coupled by near-field
interactions. The size- and momentum-dependent nonradiative Landau damping and radiative decay rates are
calculated analytically within an open quantum system approach. These decay rates determine the excitation
propagation along the chain. In particular, the behavior of the radiative decay rate as a function of the plasmon
wavelength leads to a transition from an exponential decay of the collective excitation for short distances to an
algebraic decay for large distances. Importantly, we show that the exponential decay is of a purely nonradiative
origin. Our transparent model enables us to provide analytical expressions for the polarization-dependent plasmon
excitation profile along the chain and for the associated propagation length. Our theoretical analysis constitutes
an important step in the quest for the optimal conditions for plasmonic propagation in nanoparticle chains.