Fig. 3
From: Pseudo-spin–valley coupled edge states in a photonic topological insulator
Propagation in the presence of disorder. Ten randomly selected rods are perturbed inward or outward relative to the plane of the figure in a small region (red box) near the boundary in each random configuration. a–c Simulation results. a The collars on the pushed rods are not in contact with either copper plate. Waves passing through the disordered region continue to propagate in the forward direction. b The rods are moved so that the collars touch the opposite plate. The wave is strongly backscattered so that a speckle pattern develops due to the interference of scattered waves. c Transmission profile in the bent path. d Experimental results. Comparison of the dwell times along the domain wall in four cases. The group velocity vg is the inverse of the slope when propagation is ballistic. Negative values of τ(ω,x) indicate that the pulse is reshaped in the limit of zero bandwidth
