Anisotropic non-Hermitian skin effect in a two-dimensional Lieb photonic crystal

TL;DR

This paper proposes a two-dimensional non-Hermitian photonic crystal model demonstrating anisotropic skin effects, validated through simulations, and offers a practical design for experimental realization using topological metamaterials.

Contribution

It introduces a Lieb lattice-based photonic crystal model exhibiting anisotropic non-Hermitian skin effects with a concrete, experimentally feasible design.

Findings

Spectral winding number indicates geometry-dependent skin modes.

Full wave simulations validate the boundary-dependent skin effect.

Design employs complex refractive indices to emulate non-Hermitian coupling.

Abstract

In this contribution paper, we construct a two-dimensional non-Hermitian (NH) photonic crystal (PhC) to prototype its anisotropic non-Hermitian skin effect (NHSE) for experimental proposal. Based on the tight-binding model for Lieb lattice with NH coupling, a nontrivial spectral winding number is pinpointed for certain eigenstates, which translates to geometry-dependent skin modes with tilt boundaries. For ease of implementation, complex refractive indices are employed for the Lieb unit cell of PhC to emulate the NH coupling. Validated by full wave simulation, our work underscores the boundary dependence of skin effect, and provides a concrete prototype design of NHSE implementable by state-of-the-art of topological metamaterial platforms.