Thursday, 30 November 2017
Dr Patrick Ledingham
Department of Physics
University of Oxford
"Atomic Ensemble Based Optical Memories for Quantum Networking"
Quantum interfaces between light and matter play a significant role in the field of quantum information science. Such an interface would allow for a quantum optical memory (QM), a device that enables the storage and on-demand retrieval of quantum states of light. This device therefore allows for the synchronisation of probabilistic processes within local and wide area networks, for example, multi-photon state generation , quantum photonic gate operations , as well as the generation, distribution and swapping of entanglement . Atomic systems are well suited for QMs as light can efficiently interact with optical transitions and be stored for long durations as excitations in the atomic medium.
In this seminar, I will present two experimental realisations of interfacing heralded single photons with ensemble based quantum memories. These experiments consisted of differing protocols implemented on complimentary platforms; a spin-wave atomic frequency comb memory with cryogenically cooled rare earth ion dopants , and off-resonant cascaded two-photon absorption in warm alkali vapours . In both experiments, the quantum nature of the retrieved light was confirmed, a stringent requirement for such a device to be useful within quantum photonic network, paving the way for larger scale implementations.
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 N. Sangouard, et al., Rev. Mod. Phys. 83, 33 (2011)
 A. Seri, et al., Phys. Rev. X 7, 021025 (2017)
 K. Kaczmarek, et al., arXiv:1704.00013 (2017)
WHEN: Thursday 30 November 2017
WHERE: Room 314, Science 3 Building
TIME: 3.00 pm–4.00 pm
All interested are welcome to attend
Light refreshments to follow in Common Room