Abstact

—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 \(300\,\,{\text{nm}} < \lambda < 900\,\,{\text{nm}}\) 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.

中文翻译：

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优质金属制成的圆形和椭圆形纳米圆柱中的等离子体共振

摘要

-由银或金制成的圆柱形纳米结构（其横截面轮廓为半轴比例不同的圆形或椭圆形）引起的TM型平面电磁波衍射的二维问题是经过考虑的。在波长范围\（300 \，\，{\ text {nm}} <\ lambda <900 \，\，{\ text {nm}} \）通过严格的数值方法计算出散射直径的光谱和散射图。研究了介质损耗，结构的几何尺寸以及平面波的入射角对散射直径和散射图的影响。结果表明，银（金）纳米结构的偶极共振位置和多极共振数取决于结构的厚度，其长度和平面波的入射角。在这种情况下，银（金）的实际损失使得不可能存在更高的多极共振。