Oral: Theoretical investigation of a 1D plasmonic chain of nanoparticles: beyond the point dipole approximation

Plasmonic lattices have significant applications, including the control of light at short length scales. Consequently, considerable attention has been devoted to the development of models to describe the physics of these metamaterials. In the case of sparse lattices, the point dipole approximation, which considers only the first Localized Surface Plasmon (LSP) mode on each particle, is satisfactory. Nevertheless, it is established that solely considering dipole-dipole interactions is inadequate for denser assemblies, where higher-order LSPs enter the game and hybridize the plasmonic modes.

In this study, we build upon the work of Weick et al., who introduced a second quantization formalism to describe the plasmonic chain. We generalize the model Hamiltonian with quadrupolar components and demonstrate that within this framework, plasmon-plasmon interactions in dense superlattices are accurately captured. Furthermore, we discuss the coupling of these complex modes with light, providing insights into the interpretation of experimental observables.