Plasmon Resonances in Circular and Elliptic Nanocylinders Made of Premium Metals

摘要

A two-dimensional problem of the diffraction of a plane electromagnetic wave of the TM type by a cylindrical nanostructure made of silver or gold, the cross-sectional contour of which is a circle or an ellipse with a different ratio of the semiaxes, is considered. In the wavelength range 300 nm lambda 900 the spectra of the scattering diameter and scattering diagrams were calculated by a rigorous numerical method. The influence of the losses of the medium, the geometric dimensions of the structure, and the angle of incidence of a plane wave on the scattering diameter and the scattering diagram are investigated. It is shown that the position of the dipole resonance and the number of multipole resonances for the silver (gold) nanostructure depend on the thickness of the structure, its length, and the angle of incidence of the plane wave. In this case, real losses of silver (gold) make it impossible for the existence of higher multipole resonances.