Topological metamaterials based on polariton rings

The Chern insulator phase is shown to emerge in two-dimensional arrays of polariton rings where time-reversal symmetry is broken due to the application of an out-of-plane magnetic field. The interplay of Zeeman splitting with the photonic analog of spin-orbit coupling [the transverse-electric–transverse-magnetic (TE-TM) splitting] inherently present in this system leads to the appearance of synthetic U(1) gauge field and the opening of topologically nontrivial spectral gaps. This results in the onset of topologically protected chiral edge states similar to those forming in quantum Hall effect. In one-dimensional zigzag arrays of polariton rings edge states similar to those appearing in the Su-SchriefferHeeger (SSH) model are formed.