Excitation of radiationless anapole mode of isotropic dielectric nanoparticles with tightly focused radially polarized beam
Abstract
A high index dielectric nano-sphere can be excited and yet remain radiationless. A method to excite the non-radiating anapole mode of a high index isotropic dielectric nanosphere is presented. With tightly focused radially polarized beam illumination, the main-contributing electric dipole mode and magnetic modes can be zero with only a weak electric quadruple contributing to the total scattering. Further, with a standing wave illumination formed by two counter-propagating focused radially polarized beam under 4π configuration, the ideal radiationless ananpole can be excited.
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