Short and Length‐Independent Group Delay Supported by Topological Edge States in Finite‐Size Su–Schrieffer–Heeger Chains

ABSTRACT In order to transport information with topological protection, we explore experimentally the short group delay using edge states in one‐dimensional (1D) Su–Schrieffer–Heeger (SSH) chains. The group delay is investigated in both one‐ and two‐dimensional (2D) models with topological non‐trivial band structures. The fast transport is inherited with the wavefunction localization, giving a stronger effective coupling strength between the mode and the measurement leads. Also the group delay in one‐dimension is independent of the system size. To verify the assertion, we implement a chain of split‐ring resonators (SRRs) and their complementary ones with controllable hopping strengths. By performing measurements on the group delay of non‐trivially topological edge states with pulse excitations, the group delay between two edge states is directly observed with chain length up to . Along the route to harness topology to protect optical information, our experimental demonstrations provide a crucial guideline for utilizing photonic topological devices.