Dye molecules as single-photon sources and large optical nonlinearities on a chip

We point out that individual organic dye molecules, deposited close to optical waveguides on a photonic chip, can act as single-photon sources. A thin silicon nitride strip waveguide is expected to collect 28% of the photons from a single dibenzoterrylene molecule. These molecules can also provide large, localized optical nonlinearities, which are enough to discriminate between one photon or two through a differential phase shift of 2 degrees per photon. This new atom-photon interface may be used as a resource for processing quantum information.