Fig. 5: Experimental demonstrations on the robustness of hyperbolic photonic topological insulators.

a, b The microscopy image of the fabricated face-centered and vortex-centered hyperbolic sample with defects. c, d The measure transmission spectra of face-centered hyperbolic samples by exciting the CPS and APS, respectively. e, f The measure transmission spectra of vertex-centered hyperbolic samples by exciting the CPS and APS, respectively. g, h Measured field distributions of topological edge states with the excited pseudo-spins being CPS and APS in face-centered hyperbolic photonic topological insulators. i, j Measured field distributions of topological edge states with the excited pseudo-spins being the CPS and APS in the vortex-centered hyperbolic photonic topological insulator.