Chiral Dichroism in Resonant Metasurfaces with Monoclinic Lattices

TL;DR

This paper demonstrates that resonant metasurfaces with monoclinic lattices can exhibit chiral optical responses due to lattice and substrate asymmetries, confirmed through experimental interactions with polarized light.

Contribution

It introduces a mode chirality parameter to quantify lattice chiral eigenmodes and shows chiral responses in achiral meta-atoms within monoclinic lattices.

Findings

Achieved chiral optical response in monoclinic lattice metasurfaces

Experimental confirmation of selective circularly polarized light interactions

Introduction of a mode chirality parameter for quantifying lattice chirality

Abstract

We demonstrate that chiral response can be achieved in resonant metasurfaces with a monoclinic lattice symmetry (the so-called Bravais oblique lattices) where the mirror symmetry is broken by the lattice asymmetry and also by a substrate, whereas each individual meta-atom remains fully achiral. We describe the underlying physics by introducing a mode chirality parameter as a quantitative measure of the lattice chiral eigenmodes. We confirm experimentally selective linear and nonlinear chiral interaction of resonant silicon metasurfaces with circularly polarized light.