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

## TL;DR

This paper experimentally investigates non-diffracting states in one-dimensional Floquet photonic topological insulators, revealing three classes of states including topologically protected edge states and bulk modes with distinct topological features.

## Contribution

It identifies and characterizes three classes of non-diffracting states in Floquet photonic lattices, linking them to topological properties and transitions.

## Key findings

- Identification of topologically protected edge states
- Discovery of bulk modes with different topological features
- Observation of a topological transition in bulk modes

## 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 state. The first one corresponds to topologically protected edge states, recently predicted in Floquet topological insulators, while the second and third are both bulk modes. One of them testifies of a topological transition, although presenting topological features different from those of the edge states, whether the other one result from specific band structure engineering.