Topological edge states of Kekulé-type photonic crystals induced by a synchronized rotation of unit cells
Rui Zhou, Hai Lin, Yangjié Liu, Xintong Shi, Rongxin Tang, Yanjie Wu, Zihao Yu
Abstract
Generating and manipulating Dirac points in artificial atomic crystals has received attention, especially in photonic systems due to their ease of implementation. In this Letter, we propose a two-dimensional photonic crystal made of a Kekul\'e lattice of pure dielectrics, where the internal rotation of cylindrical pillars induces optical Dirac-degeneracy breaking. Our calculated dispersion reveals that the synchronized rotation reverses bands and switches parity as well so as to induce a topological phase transition. Our simulation demonstrates that such topologically protected edge states can achieve robust transmission in defect waveguides under deformation, and therefore provides a pragmatically tunable scheme to achieve reconfigurable topological phases.