  Creating non-classical states of light from simple quantum systems together
with classical resources is a challenging problem. We show how chiral emitters
under a coherent drive can generate non-classical photon states. For our
analysis, we select a specific temporal mode in the transmitted light field,
resulting in a coupled master equation for the relevant mode and the chiral
emitters. We characterise the mode's state by its Wigner function and show that
the emission from the system predominantly produces mixtures of
few-photon-added coherent states. We argue that these non-classical states are
experimentally accessible and show their application for quantum metrology.

Quantum Physics