Experimental topological photonic superlattice

Topological phase, possessing inherent robustness against disorder, plays a central role in understanding matter, tailoring properties of artificial materials, and holding the promise of fault-tolerant quantum simulation and computing. Various topological phases and accessible controllability are being enthusiastically pursued in a wide spectrum ranging from condensed-matter to photonic systems. Recently, a topological photonic superlattice with arbitrary number of sites in each unit cell was proposed to provide richer topological properties. Here we successfully map such a multipartite structure into a photonic chip by using a femtosecond laser direct writing technique and demonstrate a direct observation of topological photonic superlattices in the quantum regime. Besides the tunable number of topologically protected edge states, we also observe stable interface states induced by the interference of topological linear modes, which exhibits Bloch-oscillation-like breathing dynamic behavior but free of nonlinearity.