Fig. 3.
Dislocation in the topological photonic crystal. a Forming the dislocation. A half column of unit cells in the red-dashed region is taken away. The rest of the photonic crystal is compressed toward the red-dashed region to restore the lattice order except at the dislocation. b Experimental sample with a dislocation of Burgers vector B = (ax, 0) and an inserted chunk of topologically trivial photonic crystal. c Confirmation of the π phase elapse of the relative phase between the opposite edge channels in the presence of the dislocation from simulation. d Field distribution measured in the two-points pumping scheme