Localized surface plasmon modes in a system of two interacting metallic cylinders

TL;DR

This paper investigates the optical response and surface plasmon modes in a system of two closely spaced metallic cylinders, analyzing resonance frequencies, field enhancements, and the effects of geometry and losses through numerical and analytical methods.

Contribution

The study extends analytical models to include retardation effects and provides a comprehensive comparison with numerical simulations for plasmon modes in coupled metallic cylinders.

Findings

Resonance frequencies depend on geometrical parameters.

Field enhancement occurs in the gap between cylinders.

Retardation effects significantly influence plasmon modes.

Abstract

We study an optical response of a system of two parallel close metallic cylinders having nanoscale dimensions. Surface plasmon excitation in the gap between the cylinders are specifically analyzed. In particular, resonance frequencies and field enhancement were investigated as functions of geometrical characteristics of the system and Ohmic losses in the metal. The results of numerical simulations were systematically compared with the analytical theory, obtained in the quasi-static limit. The analytical method was generalized in order to take into account the retardation effects. We also present the physical qualitative picture of the plasmon modes, which is validated by numerical simulations and analytical theory.