Atomic quantum memory utilising a Bragg controlled cavity

Quantum memories are needed to synchronise probabilistic operations in quantum photonic information processing. There are many proposals for quantum memories but to date none of them have met all the performance requirements for effective photonic synchronisation applications. These include low noise, on-demand readout, high efficiency, broad signal acceptance bandwidth. Furthermore, for scalability, the quantum memory will also preferably operate in the telecomms C-band, at room temperature and in a platform that can be miniaturised and integrated. Here we will pursue a proposal to implement quantum memory in warm rubidium vapour by inducing, with an external control laser, a rapidly switchable Bragg structure using the near-resonant Kerr effect. The Bragg structure will serve as a switchable input-output coupler for a storage cavity, allowing the noise-free confinement of a signal field for a controllable time. The project will involve the construction of a laser system for dressing the atomic vapour and pulse shaping to implement fast switching of the control beams. It may be possible to implement this scheme in the core of a hollow microstructured fibre. This would be appealing given the expertise in photonic crystal fibre design and fabrication here at the CPPM in Bath. The output of the project has the potential to open a route to freely scalable quantum photonics that could have implications for quantum computing and quantum communications, which would be of significant commercial interest.