Cylindrical vector beams reveal radiationless anapole condition in a resonant state

• 作者: Yudong Lu Yi Xu Xu Ouyang Mingcong Xian Yaoyu Cao Kai Chen Xiangping Li
• 来源期刊: 光电进展（英文版）
• 年，卷（期）: 2022,（4）
• 所属期刊栏目: Original Article
• 页码范围: 69-75
• 页数: 7页
• 语种: 英文
• DOI: 10.29026/oea.2022.210014

摘要

Nonscattering optical anapole condition is corresponding to the excitation of radiationless field distributions in open res-onators, which offers new degrees of freedom for tailoring light-matter interaction. Conventional mechanisms for achiev-ing such a condition relies on sophisticated manipulation of electromagnetic multipolar moments of all orders to guaran-tee superpositions of suppressed moment strengths at the same wavelength. In contrast, here we report on the excita-tion of optical radiationless anapole hidden in a resonant state of a Si nanoparticle utilizing a tightly focused radially po-larized (RP) beam. The coexistence of magnetic resonant state and anapole condition at the same wavelength further enables the triggering of resonant state by a tightly focused azimuthally polarized (AP) beam whose corresponding elec-tric multipole coefficient could be zero. As a result, high contrast inter-transition between radiationless anapole condition and ideal magnetic resonant scattering can be achieved experimentally in visible spectrum. The proposed mechanism is general which can be realized in different types of nanostructures. Our results showcase that the unique combination of structured light and structured Mie resonances could provide new degrees of freedom for tailoring light-matter interaction, which might shed new light on functional meta-optics.