Non-reciprocal few-photon devices based on chiral waveguide-emitter couplings

Understand

We demonstrate the possibility of designing efficient, non reciprocal few-photon devices by exploiting the chiral coupling between two waveguide modes and a single quantum emitter.

• We show how this system can induce non-reciprocal photon transport at the single-photon level and act as an optical diode.
• Afterwards, we also show how the same system shows a transistor-like behaviour for a two-photon input.
• The efficiency in both cases is shown to be large for feasible experimental implementations.