Exact polarizability and plasmon resonances of partly buried nanowires

TL;DR

This paper derives exact analytical formulas for the polarizability and plasmon resonances of partly buried nanowires, enabling fast and precise analysis of complex plasmonic nanostructures on substrates.

Contribution

It provides closed-form expressions for polarizability of conjoined half-cylinders on substrates, advancing the analysis of nanowire plasmonics.

Findings

Substrate significantly affects plasmon resonance spectral location.

Analytical formulas facilitate quick and accurate nanowire analysis.

Results serve as benchmarks for numerical methods.

Abstract

The electrostatic polarizability for both vertical and horizontal polarization of two conjoined half-cylinders partly buried in a substrate is derived in an analytical closed-form expression. Using the derived analytical polarizabilities we analyze the localized surface plasmon resonances of three important metal nanowire configurations: (1) a half-cylinder, (2) a half-cylinder on a substrate, and (3) a cylinder partly buried in a substrate. Among other results we show that the substrate plays an important role for spectral location of the plasmon resonances. Our analytical results enable an easy, fast, and exact analysis of many complicated plasmonic nanowire configurations including nanowires on substrates. This is important both for comparison with experimental data, for applications, and as benchmarks for numerical methods.