Photonic analog of graphene model and its extension -- Dirac cone, symmetry, and edge states --

TL;DR

This paper explores the properties of honeycomb lattice photonic crystals, revealing multiple Dirac cones, controllable band gaps, and novel edge states influenced by symmetry, with implications for topological photonics.

Contribution

It provides a theoretical framework for understanding bulk and edge states in photonic graphene analogs, including symmetry effects and topological relations.

Findings

Multiple Dirac cones in photonic band structure

Controllable mass gaps via symmetry breaking

Edge states reflecting crystal symmetries

Abstract

This paper presents a theoretical analysis on bulk and edge states in honeycomb lattice photonic crystals with and without time-reversal and/or space-inversion symmetries. Multiple Dirac cones are found in the photonic band structure and the mass gaps are controllable via symmetry breaking. The zigzag and armchair edges of the photonic crystals can support novel edge states that reflect the symmetries of the photonic crystals. The dispersion relation and the field configuration of the edge states are analyzed in detail in comparison to electronic edge states. Leakage of the edge states to free space is inherent in photonic systems and is fully taken into account in the analysis. A topological relation between bulk and edge, which is analogous to that found in quantum Hall systems, is also verified.