# Hybrid plasmonic waveguide coupling of photons from a single molecule

## TL;DR

This paper demonstrates the coupling of single-molecule photon emission into a hybrid plasmonic waveguide, showing potential for quantum-photonic circuit integration with measurable coupling efficiency.

## Contribution

It introduces a hybrid gap plasmon waveguide system for single-molecule photon emission and characterizes its coupling efficiency and emission properties.

## Key findings

- Coupling efficiency of 11.6% measured.
- Single molecule emission confirmed via correlation functions.
- Remote out-coupling of emitted photons demonstrated.

## Abstract

We demonstrate the emission of photons from a single molecule into a hybrid gap plasmon waveguide (HGPW). 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 auto-correlation 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 $\beta_{WG}=11.6(1.5)\%$. This type of structure is promising for building new functionality into quantum-photonic circuits, where localised regions of strong emitter-guide coupling can be interconnected by low-loss dielectric guides.