"Photonic Topological Insulators" |
Abstract: | The direct observation of lattice edge phenomena has recently gained a substantial boost by the use of photonic lattices. The optical experiments allow easy observation of wave phenomena unobservable in solid state and in cold atom experiments. Light propagating in a lattice of coupled optical waveguides evolves as would an electron in a two dimensional lattice. We use this equivalence to demonstrate wave phenomena in two dimensional lattices. Specifically, we arrange the waveguides in a honeycomb structure, resulting in a system which is equivalent to graphene, a hexagonal lattice of carbon atoms. This system was thus named photonic graphene. In my talk I focus on the observation of edge states in photonic graphene and the discovery of an edge state that was not previously predicted. I then discuss how we used photonic graphene to demonstrate the first photonic topological insulator: a photonic lattice with unidirectional, topologically protected edge states. This was also the first demonstration of a Floquet topological insulator. I end my talk by discussing some of the research that followed these discoveries and ongoing projects. |