Ratchet effect in frequency-modulated waveguide-coupled emitter arrays

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 classical structures with coupled resonators or arrays of semiconductor quantum wells as well as quantum setups with waveguide-coupled natural or artificial atoms.

Automated summary

This theoretical study explores the spatial distribution of polarizations in an array of resonant electromagnetic dipole emitters coupled to a one-dimensional waveguide. The ratchet effect, resulting in spatial asymmetry of emitter occupations under symmetrical pumping, is driven by periodic modulation of emitter resonance frequencies. The research identifies optimal conditions for maximal asymmetry and demonstrates that the ratchet effect can be enhanced by the formation of topological electromagnetic edge states enabled by frequency modulation.