Journal of Quantitative Spectroscopy and Radiative Transfer ( IF 2.3 ) Pub Date : 2020-06-30 , DOI: 10.1016/j.jqsrt.2020.107192 Mohammad R. Malekfar , Mehrdad Shokooh-Saremi , Mir Mojtaba Mirsalehi
Light-matter interaction in all-dielectric nanoparticles has attracted more attention because of the ability to control and configure light scattering on high-index nanoparticles. In the framework of the discrete dipole approximation, we theoretically applied cartesian multipole expansion to a periodic array of nanoparticles. This allows to analyze the contribution of multipole moments, including toroidal moments, in the scattering spectra of an array of infinite 1D/2D periodic structure of arbitrary shaped nanoparticles. The formulation is based on the Taylor expansion in cartesian coordinate system up to the fifth-order that includes a magnetic 16-pole and an electric 32-pole. Examples of a wide-band reflector and a wide-band transmitter made of silicon nanodisks are studied at IR wavelengths. The results show how constructive and destructive interferences of multipole terms affect the scattering field. The proposed method paves the way to design and analyze novel types of nanoscale subwavelength metasurfaces.
中文翻译:
周期离散偶极子逼近的多极展开及其在亚波长电介质阵列中的应用
由于能够控制和配置高折射率纳米粒子上的光散射,全介电纳米粒子中的光物质相互作用已引起更多关注。在离散偶极近似的框架中,我们在理论上将笛卡尔多极展开应用于纳米粒子的周期性阵列。这允许分析任意形状的纳米粒子的无限一维/二维周期结构阵列的散射光谱中的多极矩(包括环形矩)的贡献。该公式基于笛卡尔坐标系中的泰勒展开直至五阶,该阶包括磁16极和电32极。在红外波长下研究了由硅纳米盘制成的宽带反射器和宽带发射器的示例。结果表明,多极项的相长干涉和相消干涉如何影响散射场。所提出的方法为设计和分析新型的纳米级亚波长超颖表面铺平了道路。