Transverse Kerker Effect for Dipole Sources

Near-field directionality governed by asymmetric dipole-matter interactions

Directionally molding the near-field and far-field radiation lies at the heart of nanophotonics and is crucial for applications such as on-chip information processing and chiral quantum networks. The most fundamental model for radiating structures is a dipolar source located inside homogeneous matter. However, the influence of matter on the directionality of dipolar radiation is oftentimes overlooked, especially for the near-field radiation. As background, the dipole-matter interaction is intrinsically asymmetric and does not fulfill the duality principle, originating from the inherent asymmetry of Maxwell's equations, i.e., electric charge and current density are ubiquitous but their magnetic counterparts are non-existent to elusive. We find that the asymmetric dipole-matter interaction could offer an enticing route to reshape the directionality of not only the near-field radiation but also the far-field radiation. As an example, both the near-field and far-field radiation directionality of the Huygens dipole (located close to a dielectric-metal interface) would be reversed if the dipolar position is changed from the dielectric region to the metal region.

Annular and unidirectional transverse scattering with high directivity based on magnetoelectric coupling

Transverse scattering is a special directional scattering perpendicular to the propagation direction, which has attracted great interest due to its potential applications from directional antennas, optical metrology to optical sensing. Here we reveal annular transverse scattering and unidirectional transverse scattering by magnetoelectric coupling of Omega particle. The annular transverse scattering can be achieved by the longitudinal dipole mode of the Omega particle. Furthermore, we demonstrate the highly asymmetric unidirectional transverse scattering by adjusting the transverse electric dipole (ED) and longitudinal magnetic dipole (MD) modes. Meanwhile, the forward scattering and backward scattering are suppressed by the interference of transverse ED and longitudinal MD modes. In particular, the lateral force exerted on the particle is accompanied by the transverse scattering. Our results provide a useful toolset for manipulating light scattered by the particle and broaden the application range of the particle with magnetoelectric coupling.

Inverse design of coupled subwavelength dielectric resonators with targeted eigenfrequency and Q factor utilizing deep learning

Subwavelength all-dielectric resonators supporting Mie resonances are promising building blocks in nanophotonics. The coupling of dielectric resonators facilitates advanced shaping of Mie resonances. However, coupled dielectric resonators with anisotropic geometry can only be designed by time-consuming simulation utilizing parameter scanning, hampering their applications in nanophotonics. Herein, we propose and demonstrate that a combination of two fully connected networks can effectively design coupled dielectric resonators with targeted eigenfrequency and Q factor. Typical examples are given for validating the proposed network, where the normalized deviation rates of eigenfrequency and Q factor are 0.39% and 1.29%, respectively. The proposed neutral network might become a useful tool in designing coupled dielectric resonators and beyond.