Collectively Enhanced Chiral Photon Emission from an Atomic Array near a Nanofiber.

Emitter ensembles interact collectively with the radiation field. In the case of a one-dimensional array of atoms near a nanofiber, this collective light-matter interaction does not only lead to an increased photon coupling to the guided modes within the fiber, but also to a drastic enhancement of the chirality in the photon emission. We show that near-perfect chirality can be achieved already for moderately sized ensembles, containing 10 to 15 atoms, by phase matching a superradiant collective guided emission mode via an external laser field. This is of importance for developing an efficient interface between atoms and waveguide structures with unidirectional coupling, with applications in quantum computing and communication such as the development of nonreciprocal photon devices or quantum information transfer channels.