Nonlinear topological transitions over a metasurface

We demonstrate a self-induced topological transition and the formation of topologically protected edge states in a two-dimensional array of coupled resonant cavities placed on a Kagome lattice with saturable nonlinearity introduced in the interconnecting bonds. The dynamic response of the structure is shown to be governed by an intensity-dependent band topology. Our findings uncover prospects for generating and controlling topologically nontrivial edge modes in nonlinear metasurfaces, and delineate a roadmap towards self-reconfigurable robust signal transport in various dynamic systems, ranging from acoustics to electronics and optics.