Microwave resonator lattices for topological photonics [Invited]

We present a microwave experimental setup emulating tight-binding systems that is now widely used in the realm of topological photonics. A thorough description of the experimental building blocks is presented, showing the advantages and the limits of this platform. Various experimental realizations are then described, ranging from the selective enhancement of a defect state in a non-Hermitian Su-Schrieffer-Heeger (SSH) chain, to the generation of giant pseudo-magnetic fields in deformed honeycomb lattices. Introducing nonlinear losses, the interplay between nonlinearity and topological protection can be engineered to realize a nonlinearly functionalized topological mode with promising applications in receiver protection.