Indistinguishable photons on demand from an organic dye molecule

TL;DR

This paper demonstrates on-demand generation of indistinguishable photons from a single organic dye molecule, advancing solid-state quantum light sources for quantum information applications.

Contribution

It reports Hong-Ou-Mandel interference experiments with single-molecule emitters, including a detailed theoretical analysis of photon indistinguishability factors.

Findings

Achieved two-photon interference with single-molecule emission

Developed a comprehensive model linking experimental parameters to photon indistinguishability

Identified key factors affecting photon interference visibility

Abstract

Single molecules in solid-state matrices have been proposed as sources of single-photon Fock states back 20 years ago. Their success in quantum optics and in many other research fields stems from the simple recipes used in the preparation of samples, with hundreds of nominally identical and isolated molecules. Main challenges as of today for their application in photonic quantum technologies are the optimization of light extraction and the on-demand emission of indistinguishable photons. We here present Hong-Ou-Mandel experiments with photons emitted by a single molecule of dibenzoterrylene in an anthracene nanocrystal at 3 K, under continuous wave and also pulsed excitation. A detailed theoretical model is applied, which relies on independent measurements for most experimental parameters, hence allowing for an analysis of the different contributions to the two-photon interference visibility, from residual dephasing to spectral filtering.