Hybrid plasmonic waveguide coupling of photons from a single molecule

S Grandi,E A Hinds,K D Major,C Reardon,R F Oulton,J Cambiasso,T F Krauss,M P Nielsen,A S Clark,S Boissier

doi:10.1063/1.5110275

Abstract

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.

Highlights

Despite great advances over the last decade, the wider uptake of quantum technology has been inhibited by the lack of an efficient single photon source
We demonstrate the emission of photons from a single molecule into a hybrid gap plasmon waveguide
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

Summary

INTRODUCTION

Scitation.org/journal/app after which the photon moves into the low-loss dielectric region. By controlling the hybridization in this way, it is possible to benefit from the field confinement, while still retaining a long enough propagation length that the field can emerge from the structure and be coupled out the other side This tradeoff is shown in panels (c) and (d) of Fig. 1, where the energy distribution across the device and the propagation length as a function of channel gap width are plotted. A pellicle beam splitter was placed before the objective to add two additional beam paths, allowing us to couple light in and out of the gratings (for a more detailed setup, see supplementary material Fig. S1) These paths could be connected to the excitation laser to measure transmission loss through the device, or to single-photon detectors to estimate the coupling efficiency. A 792 nm filter was placed before the fiber coupling

RESULTS AND DISCUSSION

DEDUCING THE COUPLING EFFICIENCY

SUMMARY AND FUTURE PROSPECTS