Tunable Kerker Scattering in a Self-Coupled Polaritonic Metasurface

The strong coupling between electronic transitions and resonant cavity modes, facilitated by coherent energy transfer, presents unprecedented opportunities for tailoring the photoelectronic properties of constituent components. Here, the concept of Kerker effect is leveraged to demonstrate the dynamic control of scattering directionality in dielectric nanostructures by tuning the exciton-photon coupling. First, theoretical evidence for a significant modification of the scattering directionality of a dielectric metastructure engineered by excitonic polaritons is provided. As a proof of concept, self-coupled metasurfaces composed of bulk MoS2, which exhibit a forward/backward scattering ratio up to 20, are constructed. Importantly, tunable directionality is achieved by thermally controlling the excitonic coupling to the Mie modes. The simulated results are in good agreement with the experimental measurements, and the subsequent multipole decompositions effectively elucidate the underlying mechanism, attributed to the interplay between electric and magnetic dipole modes that are modified by excitons. The findings shed light on the control of light flow in the far field through coherent light-matter interactions, thereby opening up numerous possibilities for active optical antennas and quantum emitters on a nanoscale. Tunable directional/Kerker scattering by the dielectric metasurface is achieved through the concept of strong light-matter interaction. The MoS2 self-coupled metasurfaces are built, showing the forward/backward scattering ratio up to 20 and the thermal tunability of directional scattering. This work significantly advances the knowledge and understanding of coherent light-matter interactions for controlling the light flow in the far field.image