Talk given by

C. A. Downing
Institut de Physique et Chimie des Matériaux de Strasbourg
Université de Strasbourg,
CNRS Strasbourg,
France

Abstract:

One of the primary goals of plasmonics is to confine light at subwavelength 
scales. This aim is motivated by the desire to both transport and manipulate 
light over macroscopic distances. While metallic nanostructures have been 
proposed and widely studied to achieve such 'plasmonic circuits', both radiative 
and nonradiative losses inherent to metals are rather significant. Hence, the 
possible applications for energy and information transport at the nanoscale are 
seemingly limited. Understanding the different damping mechanisms in 
radiatively-coupled metallic nanostructures is thus of paramount importance to 
the field of plasmonics, from both a fundamental point of view and in order to 
increase the efficiency of signal transmission.

We investigate the collective plasmonic modes in chains of spherical metallic 
nanoparticles that are coupled by near-field interactions. These dipolar 
interactions between the nanoparticles gives rise to collective plasmons, which 
are extended over the whole plasmonic lattice. We study both a simple chain 
composed of regularly-spaced nanoparticles [1] and a bipartite chain, which 
exhibits nontrivial topological features and novel excitations, namely massive 
Dirac bosons [2].

[1] A. Brandstetter-Kunc, G. Weick, C. A. Downing, D. Weinmann, R. A. Jalabert, 
Nonradiative limitations to plasmon propagation in chains of metallic 
nanoparticles, Phys. Rev. B 94, 205432 (2016)

[2] C. A. Downing and G. Weick, Topological collective plasmons in bipartite 
chains of metallic nanoparticles (submitted to Phys. Rev. B).