Gap solitons in a one-dimensional driven-dissipative topological lattice

Nonlinear topological photonics is an emerging field that aims to extend the fascinating properties of topological states to a regime where interactions between the system constituents cannot be neglected. Interactions can trigger topological phase transitions, induce symmetry protection and robustness properties for the many-body system. Here, we report the nonlinear response of a polariton lattice that implements a driven-dissipative version of the Su–Schrieffer–Heeger model. We first demonstrate the formation of topological gap solitons bifurcating from a linear topological edge state. We then focus on the formation of gap solitons in the bulk of the lattice and show that they exhibit robust nonlinear properties against defects, owing to the underlying sublattice symmetry. Leveraging the driven-dissipative nature of the system, we discover a class of bulk gap solitons with high sublattice polarization. We show that these solitons provide an all-optical way to create a non-trivial interface for Bogoliubov excitations. Our results show that coherent driving can be exploited to stabilize new nonlinear phases and establish dissipatively stabilized solitons as a powerful resource for topological photonics.