Lattice Kerker effect in the hexagonal boron nitride antenna array

TL;DR

This paper demonstrates how hexagonal boron nitride (hBN) antenna arrays can achieve a lattice Kerker effect, enabling highly directional light scattering with near-zero reflectance, useful for mid-infrared metasurfaces.

Contribution

It introduces the concept of lattice Kerker effect in hBN antenna arrays, showing how collective modes and resonance overlap lead to directional scattering.

Findings

Resonance overlap reduces array reflectance significantly.

Generalized Kerker condition is satisfied in hBN arrays.

Potential for mid-infrared metasurface applications.

Abstract

Subwavelength particles with hyperbolic light dispersion in the constituent medium are a promising alternative to plasmonic, high-refractive-index dielectric, and semiconductor structures in the practical realization of nanoscale optical elements. Hexagonal boron nitride (hBN) is a layered van der Waals material with natural hyperbolic properties and low-loss phonon-polaritons at the same time. In this work, we consider multipole excitations and antennas properties of hBN particles with an emphasis on the periodic arrangement and collective array modes. We analyze excitation of lattice resonances in the antenna array and effect of resonance shifts and overlap with other multipoles supported by particles in the lattice. A decrease of reflectance from the array is achieved with appropriate lattice spacing (periods) where the electric and magnetic multipoles overlap, and the resonance oscillations are in phase and comparable in magnitude. We theoretical demonstrate that generalized Kerker condition is satisfied in this case, and hBN antennas in the array efficiently scatter light in the predominantly forward direction resulting in near-zero reflectance. The resonant lattice Kerker effect with hyperbolic-medium antennas can be applied in developing metasurfaces based on hBN resonators for mid-infrared photonics.