Optical characteristics of square-latticed metasurfaces are analyzed by equations derived from a dipole-quadrupole system. For the metasurface composed of Si nanospheres, meta-atoms maintain the anapole characteristics of the single scatterer, which are not affected by the lattice period. The far-field response of the metasurface thus can be engineered without significantly disturbing near-fields in meta-atoms. In addition, as exhibited with Ag/Si core–shell nanospheres, the transmittance of metasurface at anapole can also be modulated and even nulled by shifting the lattice magnetic dipole and quadrupole resonances. In a small-period metasurface, the near-field interaction of adjacent meta-atoms manipulates the lattice resonance behavior, leading to significant modulation in transmittance at anapole.

中文翻译：

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亚原子偶极子的超表面的光学特性

通过从偶极-四极系统导出的方程对方格超表面的光学特性进行了分析。对于由Si纳米球组成的超表面，亚原子保持单个散射体的偶极特性，不受晶格周期的影响。因此，可以设计超颖表面的远场响应，而不会显着干扰超原子中的近场。另外，正如Ag / Si核壳纳米球所展示的那样，通过改变晶格磁偶极子和四极子共振，也可以调节偶极子超表面的透射率，甚至使之无效。在小周期超颖表面中，相邻亚原子的近场相互作用控制了晶格共振行为，从而导致了偶极处透射率的显着调制。