Strongly correlated states of light in chiral chains of three-level quantum emitters

We study the correlated transport of photons through a chain of three-level emitters that are coupled chirally to a photonic mode of a waveguide. It is found that this system can transfer a classical input into a strongly correlated state of light in a unitary manner, i.e. without the necessity of nonlinear photon losses. In particular, we shows that the collective interaction with the emitter ensemble leads to the emergence of highly antibunched light with long-range correlations upon crossing a critical length of the chain. By operating close to conditions of electromagnetically induced transparency of the three-level medium, the high degree of antibunching and photon transmission can be maintained in the presence of moderate losses. These features, combined with the robustness against number fluctuations, suggest a promising mechanism for single-photon generation and may open the door to exploring correlated quantum many-body states of light.