Non-diffracting states in one-dimensional Floquet photonic topological insulators

Abstract

One-dimensional laser-written modulated photonic lattices are known to be particularly suitable for diffraction management purposes. Here, we address the connection between discrete non-diffracting states and topological properties in such devices through the experimental observation and identification of three classes of non-diffracting states. The first one corresponds to topologically protected edge states, recently predicted in Floquet topological insulators, while the second and the third are both bulk modes. One of them testifies a topological transition, although presenting topological features different from those of the edge states, while the other one results from specific band structure engineering.