Figure 5: Propagation characteristics of the edge states between two photonic insulators.
From: Experimental realization of photonic topological insulator in a uniaxial metacrystal waveguide
(a) Edge state dispersion for the boundary between PTI and POI. (b) Measured transmissions for the rightward (solid) and leftward (dotted) directions. (c) Phase differences between the Ez and Hz components at the right exit when the source is placed at either the left entrance (black), in the 10th hole (red) or in the 13th hole (blue). An obvious phase plateau at −50° appears in the complete bandgap no matter where the source locates, since only the spin-up rightward state can be detected at the right end. (d) Phase differences between the Ez and Hz components when the exit is on the left and the source is placed at the right entrance (black), in the 29th hole (red) or in the 26th hole (blue). The phase differences stabilize around 130°. Both c,d demonstrate the spin-filtered feature of the gapless topological states between PTI and POI. (e–h) results for the edge between PTI and air waveguide. (i–l) results for the edge between POI and air waveguide.
