Theoretical Study of Gold Nanoparticles Randomly Dispersed on a Dielectric/Gold Substrate.

We theoretically study random arrangements of cylindrical gold nanoparticles (NPs) deposited on a dielectric/gold substrate. We use two methods, namely the Finite Element Method (FEM) and the Coupled Dipole Approximation (CDA) method. The FEM is increasingly used to analyze the optical properties of NPs, but calculations for arrangements containing a large number of NPs have a high computational cost. On the contrary, the CDA has the advantage to drastically reduce the computation time and the memory demand compared to the FEM. Nevertheless, as the CDA involves modeling each NP as a single electric dipole through the polarizability tensor of a spheroidal-shaped NP, it may be an insufficiently accurate method. Therefore, the main purpose of this article is to verify the validity of using the CDA in order to analyze such a kind of nanosystems. Finally, we capitalize on this methodology to draw some tendencies between statistics of NPs' distributions and the plasmonic properties.