Topological, quantized transport has been limited to slowly varying potentials. The reason is that any nonvanishing driving frequency changes the topological parameter space from a circle to a torus, with band gaps opening in the band structure of the driven system. Here, in a collaboration of theory and experiment, the authors show that a topologically nontrivial band structure and associated quantized transport can be restored by non-Hermitian Floquet engineering at a driving frequency as large as the band gap of the nondissipative system. They realize this effect experimentally by means of periodically modulated, plasmonic waveguide arrays.
Read article at Nature Communications: https://doi.org/10.1126/science.abe9869