Topological Edge State in the Two-Dimensional Stampfli-Triangle Photonic Crystals

Optical topological insulators (OTIs) based on photonic crystals with ${C}_{6}$ symmetry are of interest for applications in integrated optics, offering special properties such as robustness, backscattering suppression, and defect immunity. These systems can be created with all-dielectric materials and no magnetic field, but progress is held back by technical difficulties. This study reveals the relationship between topological properties and structural parameters, and thus how to make OTIs with better adjustability by changing only the diameter of the cylinders in the basic structural unit of the photonic crystal.