Observation of Topological Band Gap Solitons

Understand

Topological materials exhibit properties dictated by quantised invariants that make them robust against perturbations.

• This topological protection is a universal wave phenomenon that applies not only in the context of electrons in solid-state materials but also to photonic systems, ultracold atoms, mechanical systems, circuits, exciton-polaritons and beyond.
• However, the vast majority of research in these systems has focused on the linear domain, i.e., where inter-particle interactions do not play a role.
• Here, we experimentally observe solitons -- waves that propagate without changing shape as a result of nonlinearity -- in the bulk of a photonic Floquet topological insulator.