Molecular single photon sources for quantum communication and enhanced sensing

The pioneering experiments by Hanbury and Twiss are considered by many as the beginnings of experimental quantum optics. These experiments are now particularly relevant in the context of quantum photonics and the characterization of single photon sources. After introducing these experiments and concepts, I will discuss molecular single photon sources, which are rapidly emerging as highly competitive contenders for quantum photonics. They combine the tunability and malleability typically associated with semiconductor based systems, such as quantum dots, and the high purity typically found in atomic systems. Here I will focus on a particular molecule/nanocrystal (BDT/antracene) hybrid system that exhibits a very high, on demand, single photon emission purity, even at room temperature. This system can easily be processed and integrated into various photonic and sensing applications. Two main applications will be discussed in more detail: (1) ambient quantum key distribution [1] with concrete advantages over conventional attenuated laser pulses and (2) local (10-100mnm) contact-less temperature sensing at cryogenic temperatures. This is particularly interesting when all other techniques fail. 

This work was done in collaboration with the Toninelli group at LENS and the University of Florence.

[1] G.Murtaza, et al. arXiv:2202.12635 (2022)