The Influence of Particle Shapes on the Optical Response of Nearly Touching Plasmonic Nanoparticle Dimers

In this paper we provide a systematic analysis of the optical properties of different nanoscopic dimer structures with relatively small gap distances. In particular, we have focused on two different aspects, namely the feasibility of functionalizing optical nanodimers while analyzing the influence of different particle shapes with respect to the proper contact regions, as well as the impact of potential fabrication imperfections. Both scenarios-functionalization and perturbation-are rooted in the significant variations of the nanodimer's optical properties, such as a dramatically altered field enhancement, together with a significant shift in the resonance wavelength. Referring to a state-of-the-art nanoprocessing technology we have forecasted in our outlook that emergent changes in the chemical composition especially of the metallic part will add a further dimension to the uncertainties that have to be faced in functional nanoparticle desing. Hence, the proper determination of the nanoparticle's shape and the corresponding material properties may become constitutive in any design and optimization procedure of functional plasmonic nanostructures.