Photonic quantum networks would enable quantum computing, guaranteed-secure communications and enhanced sensing capabilities, running at high bandwidths in ambient conditions
To exploit the full potential of photonic networks, the capability to switch and re-time optical signals is required. But this has proved challenging for quantum signals, since amplification adds noise at the quantum level, and so passive losses must be carefully eliminated. Conventional photonic switching and storage solutions based on electro-optical phase modulation and bulk non-linearities are too lossy or not suitable for operation at the level of individual light quanta.
A promising route to fast, low-loss, quantum-compatible fibre-integrated switching devices is the incorporation of atomic vapour into hollow fibres. This is the focus of the proposed PhD project.
In recent work at Oxford, GHz bandwidth photons were stored in, and retrieved from, a warm alkali vapour, via off-resonant cascaded absorption (ORCA) [Kaczmarek et al. Phys. Rev. A 97.4 042316 (2018)]. The same protocol has since been implemented at the Weizmann Institute [Finkelstein et al. Science advances 4.1 eaap8598 (2018)] and at the University of Adelaide [Perella et al. unpublished communication (2018)]. In parallel work at Bath, in partnership with NQIT and TMD Ltd., we have explored the use of hollow-fibre vapour cells for magnetometry and atomic clocks. In this project, the student will further develop this initial work, with the aim of splicing fibre vapour cells directly into single-mode fibres, and demonstrating fibre-integrated light storage via ORCA at the quantum level.
The student will be based at the Centre for Photonics and Photonic Materials (CPPM) at the University of Bath, and supervised by Dr. Josh Nunn.
The work will proceed in close collaboration with the group of Dr. Pete Mosley (CPPM director) and forms part of the UK Quantum Technology Programme, under the aegis of the Phase II Hub in Quantum Simulation and Quantum Computation, in which Bath Physics is participating.
Applicants should hold, or expect to receive, a First Class or high Upper Second Class UK Honours degree (or the equivalent qualification gained outside the UK) in a relevant subject. A master’s level qualification would also be advantageous.
Informal enquiries should be directed to Dr Josh Nunn, [email protected]
Formal applications should be made via the University of Bath’s online application form: https://samis.bath.ac.uk/urd/sits.urd/run/siw_ipp_lgn.login?process=siw_ipp_app&code1=RDUPH-FP01&code2=0013
Please ensure that you quote the supervisor’s name and project title in the ‘Your research interests’ section.
More information about applying for a PhD at Bath may be found here: http://www.bath.ac.uk/guides/how-to-apply-for-doctoral-study/
Anticipated start date: 30 September 2019.
Note: applications may close earlier than the advertised deadline if a suitable candidate is found; therefore, early application is strongly recommended.
Kaczmarek, K. T., et al. "High-speed noise-free optical quantum memory." Physical Review A 97.4 (2018): 042316.
Finkelstein, Ran, et al. "Fast, noise-free memory for photon synchronization at room temperature." Science advances 4.1 (2018): eaap8598.
Kaczmarek, Krzysztof T., et al. "Ultrahigh and persistent optical depths of cesium in Kagomé-type hollow-core photonic crystal fibers." Optics letters 40.23 (2015): 5582-5585.
Sprague, M. R., et al. "Broadband single-photon-level memory in a hollow-core photonic crystal fibre." Nature Photonics 8.4 (2014): 287.