Boissier, SebastienSebastienBoissierSchofield, RossRossSchofieldJin, LinLinJinOvvyan, AnnaAnnaOvvyanNur, SalahuddinSalahuddinNurKoppens, Frank HLFrank HLKoppensToninelli, CostanzaCostanzaToninelliPernice, Wolfram HPWolfram HPPerniceMajor, KyleKyleMajorHinds, EdEdHindsClark, AlexanderAlexanderClark2021-03-042021-03-042021-01-29Nature Communications, 2021, 122041-1723http://hdl.handle.net/10044/1/86365Extinction spectroscopy is a powerful tool for demonstrating the coupling of a single quantum emitter to a photonic structure. However, it can be challenging in all but the simplest of geometries to deduce an accurate value of the coupling efficiency from the measured spectrum. Here we develop a theoretical framework to deduce the coupling efficiency from the measured transmission and reflection spectra without precise knowledge of the photonic environment. We then consider the case of a waveguide interrupted by a transverse cut in which an emitter is placed. We apply that theory to a silicon nitride waveguide interrupted by a gap filled with anthracene that is doped with dibenzoterrylene molecules. We describe the fabrication of these devices, and experimentally characterise the waveguide coupling of a single molecule in the gap.© The Author(s) 2021. This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. The images or other third party material in this article are included in the article’s Creative Commons license, unless indicated otherwise in a credit line to the material. If material is not included in the article’s Creative Commons license and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this license, visit http://creativecommons.org/licenses/by/4.0/.Journal Articlehttps://www.dx.doi.org/10.1038/s41467-021-20915-zUF160475RGF\EA\180203EP/R044031/1EP/P030130/1RGF/R1/180066