Nonlinearity-induced photonic topological insulator

Abstract

Switching on topology Ways to control and design topological features in various systems are being studied intensively because the resulting properties tend to be robust against things such as scattering and defects, endowing the system with topological protection. Maczewsky et al. now look to another regime in optics to show that optical nonlinearity can induce a topological change in the properties of a photonic lattice. At low excitation power, probe light uniformly leaks into the rest of the lattice, an optically trivial phase. Above a threshold power, optical nonlinearity induces a topological change in the properties of the photonic lattice, and probe light is confined to propagate along the edge of the structure. These results illustrate a route to dynamically control the propagation of light. Science , this issue p. 701