We demonstrate the emission of photons from a single molecule into a hybrid gap plasmon waveguide. Crystals of anthracene, doped with dibenzoterrylene (DBT), are grown on top of the waveguides. We investigate a single DBT molecule coupled to the plasmonic region of one of the guides and determine its in-plane orientation, excited state lifetime, and saturation intensity. The molecule emits light into the guide, which is remotely out-coupled by a grating. The second-order autocorrelation and cross-correlation functions show that the emitter is a single molecule and that the light emerging from the grating comes from that molecule. The coupling efficiency is found to be βWG = 11.6(1.5)%. This type of structure is promising for building new functionality into quantum-photonic circuits, where localized regions of strong emitter-guide coupling can be interconnected by low-loss dielectric guides.
