Haldane quantum Hall effect for light in a dynamically modulated array of resonators

Topological insulators have attracted abundant attention for a variety of reasons-notably, the possibility for lossless energy transport through edge states protected against disorder. Topological effects such as the quantum Hall state can be induced through a gauge field, which is, however, hard to create in practice, especially for charge-neutral particles. One way to induce an effective gauge potential is through a dynamic, time-periodic modulation of the lattice confining such particles. In this way, the Haldane quantum Hall effect was recently observed in a cold-atom system. Here, we show how this same effect can be induced for light confined to a lattice of identical optical resonators, using an on-site modulation of the resonant frequencies. In this system, coupled-mode analysis shows the presence of one-direction edge states immune to backscattering losses. We also discuss possible realizations of the model, which could enable slow-light devices of unprecedented quality. (C) 2016 Optical Society of America