Experimental realization of three-dimensional all-dielectric photonic topological insulators

Significant progress has recently been made in the study of topological states in photonic topological systems. Being motivated by the recent theoretical proposal of three-dimensional topological structures based on high-permittivity bianisotropic particles, here we verify experimentally the concept of three-dimensional all-dielectric photonic topological insulators in the microwave frequency range. We demonstrate an excitation of topological surface states in the near field as well as their impact on the far-field radiation where the propagation direction is dictated by the excitation of a particular pseudo-spin.