Topological phases can be probed in the presence of a suitable time-periodic driving, where the associated Hamiltonian is periodic in time. Prof. Thomson and his research team exploit slowly-driven photonic lattices to demonstrate anomalous topological edge modes which have no static analogue. These robust topological edge modes propagate one-way and are associated with a distinct topological invariant known as the winding number. This work opens an exciting route to explore topological physics in time-periodic systems operating away from the high-frequency limit.

Nature Communications 8, 13918