Topological funneling of light

A topological light funnel Because most physical systems cannot be totally isolated from their environment, some degree of dissipation or loss is expected. The successful operation of such systems generally relies on mitigating for that loss. Mathematically, such external interactions are described as non-Hermitian. Recent work has shown that controlling the gain and loss in these systems gives rise to a wide variety of exotic phenomena not expected for their isolated Hermitian counterparts. Using a time-dependent photonic lattice in which the topological properties can be controlled, Weidemann et al. show that such a structure can efficiently funnel light to the interface irrespective of the point of incidence on the lattice. Such control of the topological properties could be useful for nanophotonic applications in integrated optical chip platforms. Science , this issue p. 311