  We study theoretically the spatial distribution of the polarizations in the
array of resonant electromagnetic dipole emitters coupled to a one-dimensional
waveguide. The ratchet effect manifests itself in the spatial asymmetry of the
distribution of the emitter occupations along the array under symmetrical
pumping from both sides. The occupation asymmetry is driven by the periodic
modulation in time of the emitter resonance frequencies. We find numerically
and analytically the optimal conditions for maximal asymmetry. We also
demonstrate that the ratchet effect can be enhanced due to the formation of
topological electromagnetic edge states, enabled by the frequency modulation.
Our results apply to the classical structures with coupled resonators or arrays
of semiconductor quantum wells as well as the quantum setups with
waveguide-coupled natural or artificial atoms.
