Reconfigurable metalattices: Combining multipolar lattice resonances and magneto-optical effect in far and near fields

Abstract

The present work has elaborated the roles of near- and far-field lattice resonances (LRs) in the performance of one-dimensional metalattices composed of magneto-optically (MO) coated cylinders. By taking advantage of LR effects and MO-modified multipolar interferences, it is feasible to alter transmission or reflection with unity efficiency by turning on or off external magnetic fields. In the far field, multipolar LRs near Rayleigh anomaly (RA) can be acquired, leading to transmission suppression or enhancement for different multipolar interference mechanisms. Meanwhile, thanks to exciting degeneracy-broken multipoles, asymmetric diffractive patterns are observed despite normal incidence. However, in the diffractionless region with strong near-field couplings, we find that LR effects are capable of not only modifying scattering amplitude (>1) but also introducing phase change or even inversion. Specifically, owing to the appearance of π/2-phase rotated electric dipoles, the first and second Kerker conditions are achieved simultaneously in this work. In addition, the coupling mechanism of RA-associated LRs and MO-influenced Mie modes supported by an individual cylinder is also unveiled. Besides, a proof-of-concept example using realistic Si@InSb metalattices has also been demonstrated, showing reconfigurable performance as expected. The revealed far/near-field mechanism of interplay between LRs and MO-modified multipoles will shed new light on wavefront engineering with diffracted effects and reconfigurable features.