Edge states protected by chiral symmetry in disordered photonic graphene

TL;DR

This study experimentally explores how different types of disorder affect edge states in photonic graphene, revealing that structural disorder preserves key symmetries and properties, unlike composite disorder.

Contribution

It demonstrates experimentally that structural disorder preserves chiral symmetry and zero-energy density of states in photonic graphene, unlike composite disorder.

Findings

Structural disorder preserves chiral symmetry.

Composite disorder destroys chiral symmetry.

Edge states are maintained under structural disorder.

Abstract

We experimentally investigate the impact of uncorrelated composite and structural disorder in photonic graphene. We find that in case of structural disorder not only chiral symmetry, but also the vanishing of the density of states at zero energy is preserved. This is in contrast to composite disorder, where chiral symmetry as well as the vanishing of the density of states are destroyed. Our observations are experimentally proven by exciting edge states at the bearded edge in disordered photonic graphene.