Abstract Topological slow light exhibits potential to achieve stopped light by virtue of its widely known robust and non-reciprocal behaviours.Conventional approach for achieving topological slow light often involves flat-band engineering without disentangling the underlying physical mechanism.Here, we unveil the presence of counter-propagating waves within valley kink states as the distinctive hallmark of the slow light topological photonic waveguides.
These counter-propagating waves, supported by topological vortices along glide-symmetric Hemp Socks interface, provide significant flexibility for controlling the slowness of light.We tune the group velocity of light by changing the spatial separation between cowry shells vortices adjacent to the glide-symmetric interface.We also dynamically control the group delay by introducing a non-Hermitian defect using photoexcitation to adjust the relative strength of the counter-propagating waves.
This study introduces active slow light topological photonic device on a silicon chip, opening new horizons for topological photon transport through defects, topological light-matter interactions, nonlinear topological photonics, and topological quantum photonics.