Numerical Investigation of Topological Edge States in a GaAs-Based Three-Dimensional Chiral Photonic Crystal

Topological edge states derived from optical Weyl points were numerically investigated in a chiral photonic crystal which can be fabricated using compound semiconductor materials such as GaAs. The studied structure was a rotationally stacked woodpile structure where thin plates having a line-and-space pattern were stacked with an in-plane rotation angle of 60 degrees. This chiral photonic crystal showed optical Weyl points having finite topological charges whose signs can be changed by the structural chirality. By resolving these Weyl points due to a selection of a wavevector, we found topological edge states localized at an interface between left-handed and right-handed chiral photonic crystals.