Infrared all-dielectric Kerker metasurfaces

Area of Science:

• Metamaterials and Nanophotonics
• Computational Electromagnetics
• Dielectric Metasurfaces

Background:

• Sub-wavelength particles exhibit unidirectional scattering (Kerker conditions).
• All-dielectric metasurfaces recently demonstrated similar scattering properties.
• Controlling electromagnetic wave interaction is crucial for advanced optical devices.

Purpose of the Study:

• To formulate polarizability requirements for simultaneous forward and backward scattering (Kerker conditions) using only dipole terms.
• To demonstrate the equivalence of these conditions to "invisible metasurfaces".
• To describe perfect absorption in all-dielectric metasurfaces via an extended Kerker formalism.

Main Methods:

• Exact polarizability formulation for dipole terms.
• Development of an extended Kerker formalism for absorption.
• Utilizing a 2D hexagonal array of cylindrical resonators with tunable height.

Main Results:

• Simultaneous achievement of both Kerker conditions demonstrated using dipole polarizability.
• Equivalence between Kerker conditions and invisible metasurfaces established.
• Invisibility and perfect absorption achieved in a single metasurface structure by modifying resonator height.

Conclusions:

• The developed framework offers critical insights into the scattering response of all-dielectric metasurfaces.
• A methodology for studying exotic electromagnetic phenomena like invisibility and perfect absorption is presented.
• Tunable resonator height provides a simple method to switch between distinct electromagnetic responses.