Waveguiding properties of short linear chains of nonspherical metal nanoparticles

Abstract

We study numerically the discrete dispersion relations and waveguiding properties of relatively short linear chains of spherical and spheroidal silver nanoparticles. Simulations are based on the Drude model for the dielectric permittivity of metal and on the dipole approximation for the electromagnetic interaction of particles. We also simulate the dynamics of femtosecond optical pulse propagation along such chains. In the case that we consider (10 particles per chain), reflections from the chain terminals play a significant detrimental role. We show that dissipative traps can be used to reduce the effects of reflections. We also show that chains composed of oblate spheroids with sufficiently small aspect ratio (nanodisks) have better waveguiding properties when compared to chains made of particles with other spheroidal shapes. This includes a slower rate of decay, larger group velocity, and larger bandwidth.