Anomalous Wave Propagation in Topological Transition Metasurfaces

Metasurfaces become an effective route to the control of not only free‐space waves but also surface plasmon polaritons (SPPs). SPPs, propagating along the interface between a metal and a dielectric, show properties of strong enhancement of the local field. Thanks to these essential functionalities, manipulating SPPs in metasurfaces is of particular interest in current research. Here, observation of anomalous SPP propagation is presented when SPPs traverse an interface between two metasurfaces whose topologies of eigenmode equal‐frequency contours are different. By combining various complementary meta‐resonators, SPP propagation was ready to be redirected at the topological transition interface at will. The proposed integrated metasurfaces open unprecedented avenues for anomalous wave propagation and guidance, showing exceptional capabilities for designing photonic devices.