Fig. 4

Electromagnetic simulation of the gluing process. a–c Photonic spectrum during the gluing process with decreasing width of the chunk of the topologically trivial photonic crystal where \(L_x \!\! \prime = 4a_y \!\! \prime ,a_y \!\! \prime ,0\), respectively. The shaded regions represent the bulk photonic bands. Within the bulk photonic band gap, there are photonic states associated with edge states and localized states bound to the dislocations. d, e The field profiles of the degenerate photonic states labeled by the red arrow in a. f, g (h, i) The field profiles for the degenerate states labeled by the green (black) arrow in b (c). The green boxes enclose the dislocations