Topologically protected defect modes in all-dielectric photonic crystals.

Inspired by the studies of topological materials, topological edge states—striking examples that support robust energy transport in photonic systems—have enriched condensed matter physics. Here we propose all-dielectric photonic crystals manipulating topologically protected defect modes at the edge of the configuration, which is distinct from previous platforms where helical edge states were excited at the interface between trivial and nontrivial crystals. The localization of frequency dispersion of one-way propagating defect modes is measured. Topological protection gives rise to the pseudospin-dependent transport and robustness against perturbations. Our proposal that enables one-way defect modes is promising for benefitting the microminiaturization and application of photonic topological structures. [ABSTRACT FROM AUTHOR]