Although the study of non-radiating anapoles has long been part of fundamental physics, the dynamic anapole at optical frequencies was only recently experimentally demonstrated in a specialized silicon nanodisk structure. We report excitation of the electrodynamic anapole mode in isotropic silicon nanospheres using radially polarized beam illumination. The superposition of equal and out-of-phase amplitudes of the Cartesian electric and toroidal dipoles produces by a pronounced dip in the scattering spectra with the scattering intensity almost reaching zero - a signature of anapole excitation. The total scattering intensity associated with the anapole excitation is found to be more than 25 times weaker for illumination with radially vs. linearly polarized beams. Our approach provides a simple, straightforward alternative path to realize electrodynamic anapole mode at the optical frequencies.

中文翻译：

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介电纳米球中非辐射偶极的激发

尽管无辐射偶极子的研究一直是基础物理学的一部分，但直到最近才在专门的硅纳米盘结构中通过实验证明了光频率下的动态偶极子。我们报告了使用径向偏振光束照明在各向同性硅纳米球中的电动力偶极子模式的激发。笛卡尔电偶极和环形偶极子的等幅和异相振幅的叠加是由散射光谱中的明显下降而产生的，散射强度几乎达到零，这是偶极激发的特征。发现与偶极激发相关的总散射强度比径向偏振光束和线性偏振光束的照明弱25倍以上。我们的方法提供了一种简单，