Robust Interface States on Topological Photonic Crystals Composed of Hexagonal Rods

Over the last years, topology has been a hot field in Condensed Matter, and resources about electrical and photonic systems have shown us special behaviors that can be used in technological implementation. In particular, the interest in Topological Photonic Crystals has been increased because of their robust edge states that can emerge in a non-trivial bandgap and have special features. Those edge states are well localized around the interface between two different kinds of topologies, so they are called Interface States. Furthermore, the non-trivial topological behavior guarantees their protection against reflection, defects, and disorders. All those features make the Topological Photonic Crystal a good candidate to create channels of non-losses light transportation. Here, we propose a two-dimensional Topological Photonic Crystal composed of dielectric hexagonal rods and we study the robustness, against small defects and disorders, and localization of those modes. We induce the topological behavior by introducing a geometric perturbation, and we observe the emergence of two pseudospin Interface States that are topologically protected and robust.