Finite-Size Effects on Nanostructure Arrays*

Metallic nanostructures have emerged as powerful tools for manipulating light at the nanoscale due to their ability to support surface plasmons. These collective oscillations of conduction electrons provide strong field confinement and enhancement, making them ideal for applications including solar energy harvesting, optical sensing, and nanoscale light emission. For practical purposes, it is typical to use ensembles of plasmonic nanostructures, such as periodic arrays. This not only results in a stronger collective response than a single nanostructure, but also allows collective behavior, such as lattice resonances, to emerge. When modeling these arrays, it is convenient to assume that the system is perfectly periodic, and therefore infinite, due to the greatly reduced computational cost of this approximation. However, any implementation of periodic arrays must be finite, and the edges of the system may drastically alter its behavior. Here, we investigate the role played by finite-size effects on the optical response of nanostructure arrays. Our results help to pave the way for improved modeling of nanophotonic devices seeking to exploit the unique properties of arrays of nanostructures.