Scattering of Evanescent Wave by Periodic Array of Nanowires

TL;DR

This paper presents a boundary element method to analyze how evanescent electromagnetic waves scatter off a periodic nanowire array, revealing anomalies and validating results with known approximations.

Contribution

It extends the boundary element method to infinite gratings near dielectric interfaces and derives a Green function for evanescent wave analysis.

Findings

Rayleigh-Wood anomalies observed in period-to-wavelength dependence

Method agrees with 2D coupled dipole approximation for thin wires

Green function enables study of evanescent wave scattering

Abstract

The scattering of electromagnetic wave by a periodic array of nanowires is calculated by the boundary element method. The method is extended to the infinite grating near the interface between two dielectrics. A special Green function is derived that allows to study the evanescent wave. The Rayleigh--- Wood's anomalies are found in the period-to-wavelength dependence of the average Pointing vector in the wave zone. For thin wires the calculations are shown to agree with the two-dimensional coupled dipole approximation.