First realization of a nonlinearity-induced topological insulator

Topological insulators (TI) have been the focal point of a remarkable level of experimental effort in the past two decades [1] . Their hallmark protected and scatter-free chiral edge states underpin the enormous applicative potential of topological systems. Photonics is a particularly fertile ground for the implementation and exploration of topological phenomena [2] , ranging from the chiral propagation of protected edge states to Floquet TIs, 4D topological Hall physics, Weyl points, Anderson TIs, TIs in synthetic dimensions, non-Hermitian topological effects and even topological quantum physics. And yet, until the recent observation of solitons in a Floquet TI [3] , these experiments have been strictly limited to linear dynamics.