Surface Plasmon Resonance of a Few Particles Linear Arrays

We present a study of the enhancement of the electric field due to localized surface plasmons in a short chain of metallic nanoparticles with different shapes: spheres, cylinders and spheroids. We calculate numerically the external radiation effect on these chains and analyze besides the shape, also the influence on size, interparticle distances and number of nanoparticles, corroborating that each one plays a definitive role for the enhancement of the electric field. Particularly, we focus on the main features of the electric field in the inter-particle regions, where an enormous increasing is expected due to the longitudinal localized plasmons. The electric field distribution along the chain shows a maximum in the middle of the chain. This fact could be related to a hybridization effect as the gap between particles decreases below 2 nm, we also observe a strong enhancement with the number of nanoparticles. Also regarding the shape we find agreement with reported results on spheroids, moreover we show that lateral coupled cylinders are more flexible to tune the enhancement factor than all other.