The development of single-photon sources has been nothing but rapid in recent years, with quantum emitter-based systems showing especially impressive progress. In this article, we give an overview of the developments in single-photon sources based on single molecules. We will introduce polycyclic hydrocarbons as the most commonly used emitter systems for the realization of an organic solid-state single-photon source. At cryogenic temperatures this special class of fluorescent molecules demonstrates remarkable optical properties such as negligible dephasing, indefinite photostability, and high photon rates, which make them attractive as fundamental building blocks in emerging quantum technologies. To better understand the general properties and limitations of these molecules, we discuss sample preparation and relevant emitter parameters such as absorption and emission spectra, lifetime, and dephasing. We will also give an overview of light extraction strategies as a crucial part of a single-photon source. Finally, we conclude with a look into the future, displaying current challenges and possible solutions.
Single organic molecules for photonic quantum technologies
CNR-INO and LENS（意大利国家研究委员会光学研究所和欧洲纳米科学实验室）；Centre for Cold Matter, Blackett Laboratory, Imperial College London（帝国理工学院布莱克特冷物质中心）；ICFO − Institut de Ciencies Fotoniques, The Barcelona Institute of Science and Technology（巴塞罗那科学技术研究院光子科学研究所）；Max Planck Institute for the Science of Light（马克斯·普朗克光科学研究所）；Friedrich-Alexander University of Erlangen-Nürnberg（埃尔朗根-纽伦堡弗里德里希·阿历山大大学）；Institute of Physics, Polish Academy of Sciences（波兰科学院物理研究所）；CEMES-CNRS（法国国家科学研究中心电子与分子结构中心）
