Fig. 2: Domain-wall interface modes of RPTI and the unidirectional topological propagation feature.
From: Reprogrammable plasmonic topological insulators with ultrafast control
a Topological domain-wall interface. The interfaces A and B separate two crystal domains, which are filled with digital unit-1 (symbol “1”) and unit-2 (symbol “2”), respectively. b Projected band diagrams. The topological bandgap increases with the length s of outer arm. c Straight waveguide with a B-type nontrivial interface, where a chiral source is employed. d, e Simulated unidirectional propagations with the RCP (d) and LCP (e) excitations. White scale bar, 30 mm.
