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Quantum Molecular Photon Source

Periodic Reporting for period 1 - Q-MoPS (Quantum Molecular Photon Source)

Reporting period: 2015-05-01 to 2017-04-30

Harnessing the power of quantum mechanics in novel technologies will lead to new, fast computer architectures, completely secure communication links and enhanced sensing capabilities. At the heart of many of these technologies are quantum systems, including single particles of light, or photons. Current sources of photon are slow and probabilistic, limiting the scalability of quantum technologies. The aims of this project were to build an integrated and on-demand photon source using single organic molecules coupled to waveguides and cavities.
During the course of this project I have developed two new methods to grow mixed-molecular crystals which can be used in organic quantum technologies, including but not limited to photon sources. The first is a co-sublimation growth which has exquisite control over the crystal habit and the doping levels of single photon emitting molecules. This means crystals can be tailor made for operation in various technologies, such as photon sources or sensors, and environments, such as room temperature devices or cryogenically cooled systems. The second method is a supersaturated vapour growth. This technique produces thin crystals which are compatible with a number of planar integrated waveguide devices. Both of these techniques were published during the course of this 2-year fellowship. To understand the inner-workings of single organic molecules and their robustness against temperature fluctuations and their environement, I investigated the quantum dynamics of molecules in the presence of excess dephasing. This was published in Phys. Rev. A and was an Editor’s Suggestion. In collaboration with the University of York I have designed and fabricated a number of different photonic devices. The first are simple nanowire waveguides in silicon nitride, the second are slotted nanowire waveguides which enable a larger coupling between a molecule and a guided mode, and the third are hybrid plasmonic waveguides which use gold to further enhance light-matter interaction. Each of these devices has been shown to couple light from organic molecules, and experiments are close to yielding publishable results, with one paper currently in preparation.
The developed crystal growth techniques and understanding of how molecules behave when excited by lasers in these crystals is crucial in the development of new technologies based on organic systems. Such new technologies will lead to on-demand photon sources that will have a far reaching effect on many strands of society, from the banking sector where security is paramount, to the medical sector where new drugs and medicines could be developed by simulating quantum interactions at the nanoscale. The next step is to interface various quantum systems with classical control and prove the scalability of this technology.
An integrated waveguide with a small slot for coupling to single organic molecules.