Local-field enhancement in metallic nanoplanets

Generalized Multiparticle Mie theory is applied in order to study in detail local-field properties of metallic nanoplanets (i.e., a central cluster surrounded by small “satellite” clusters very close to its surface), obtained by ion beam techniques. Strongly asymmetric dimers are chosen as model systems in order to establish the influence of topological parameters such as satellite dimension and distance from the central cluster surface on the local-field enhancement, with calculated enhancement factors as high as ∼ 180 in the case of silver. Similar topological configurations are shown to be present in typical nanoplanet systems, with comparable local-field enhancement factors. Simulations for silver and silver–gold alloy in silica, and for gold in titania matrix are reported as examples of possible experimental systems.