Nonradiating anapole modes in dielectric nanoparticles

作者：Miroshnichenko, Andrey E.^*; Evlyukhin, Andrey B.; Yu, Ye Feng; Bakker, Reuben M.; Chipouline, Arkadi; Kuznetsov, Arseniy I.; Luk'yanchuk, Boris; Chichkov, Boris N.; Kivshar, Yuri S.

来源：Nature Communications, 2015, 6(1): 8069.

DOI：10.1038/ncomms9069

• SOLID-STATE PHYSICS
• TOROIDAL METAMATERIALS
• ELECTROMAGNETIC-FIELD
• INVISIBLE BODIES
• SCATTERING
• ELECTRODYNAMICS
• MOMENTS
• LIGHT

Nonradiating current configurations attract attention of physicists for many years as possible models of stable atoms. One intriguing example of such a nonradiating source is known as 'anapole'. An anapole mode can be viewed as a composition of electric and toroidal dipole moments, resulting in destructive interference of the radiation fields due to similarity of their far-field scattering patterns. Here we demonstrate experimentally that dielectric nanoparticles can exhibit a radiationless anapole mode in visible. We achieve the spectral overlap of the toroidal and electric dipole modes through a geometry tuning, and observe a highly pronounced dip in the far-field scattering accompanied by the specific near-field distribution associated with the anapole mode. The anapole physics provides a unique playground for the study of electromagnetic properties of nontrivial excitations of complex fields, reciprocity violation and Aharonov-Bohm like phenomena at optical frequencies.

• 出版日期2015-8