Excitation of Periodic Arrays of Nanoparticles by Localized Dipole Sources

Lauren Zundel, University of New Mexico

Photo of Lauren Zundel

Periodic arrays of metallic nanostructures are known to support collective modes known as lattice resonances. These excitations occur at wavelengths commensurate with the periodicity of the array and give rise to very strong and spectrally narrow optical responses. This makes periodic arrays ideal for a wide range of applications. Here, we analyze the excitation of lattice resonances using a localized dipole source. Specifically, we compute and analyze the spectral characteristics of the electromagnetic field produced by the array due to the presence of the point dipole. Computing this quantity, known as the Green tensor, poses a unique computational challenge, as the presence of a point dipole breaks the periodicity of the problem. We are thus required to implement a sophisticated adaptive integration method and take advantage of high-performance computing resources to efficiently perform our analysis. We find that, when a lattice resonance is excited, the Green tensor is not only much larger than that of vacuum, but also decays much more slowly with the distance. Our analysis reveals fundamental insights into the nature of lattice resonances and will aid in the exploitation of periodic arrays of nanoparticles for applications such as nanoscale energy transfer.

Abstract Author(s): Lauren Zundel, Alvaro Cuartero-González, Stephen Sanders, Antonio I. Fernández-Domínguez, Alejandro Manjavacas