Broadband single-photon-level memory in a hollow-core photonic crystal fibre

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Storing information encoded in light is critical for realizing optical buffers for all-optical signal processing1,2 and quantum memories for quantum information processing3,4. These proposals require efficient interaction between atoms and a well-defined optical mode. Photonic crystal fibres can enhance light–matter interactions and have engendered a broad range of nonlinear effects5; however, the storage of light has proven elusive. Here, we report the first demonstration of an optical memory in a hollow-core photonic crystal fibre. We store gigahertz-bandwidth light in the hyperfine coherence of caesium atoms at room temperature using a far-detuned Raman interaction. We demonstrate a signal-to-noise ratio of 2.6:1 at the single-photon level and a memory efficiency of 27 ± 1%. Our results demonstrate the potential of a room-temperature fibre-integrated optical memory for implementing local nodes of quantum information networks.

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Figure 1: Raman quantum memory in kagome hollow-core fibre.
Figure 2: Storage of classical light in a kagome hollow-core fibre.
Figure 3: Storage of single-photon-level pulses.
Figure 4: Lifetime of memory in hollow-core fibre.


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The authors thank D. Saunders for comments on the manuscript. The work was supported by the Engineering and Physical Sciences Research Council (EPSRC; EP/J000051/1), the Quantum Interfaces, Sensors, and Communication based on Entanglement Integrating Project (EU IP Q-ESSENCE; 248095), the Air Force Office of Scientific Research: European Office of Aerospace Research & Development (AFOSR EOARD; FA8655-09-1-3020), EU IP SIQS (600645), the Royal Society, the Clarendon Fund (to M.R.S.), St Edmund Hall (to M.R.S.), EU ITN FASTQUAST (to P.S.M.), and an EU Marie-Curie Fellowship (PIIF-GA-2011-300820 to X.-M.J.; PIEF-GA-2012-331859 to W.S.K.).

Author information

M.R.S. designed the experiment and built it with assistance from D.G.E., P.S.M., W.S.K. and T.F.M.C. A.A. and P.St.J.R. designed and drew the fibre and provided valuable insights. M.R.S. collected and analysed the data. J.N. and M.R.S. performed the comparison to theory. The project was conceived by M.R.S., J.N., X.M.J. and I.A.W. M.R.S. wrote the manuscript with input from all authors.

Correspondence to M. R. Sprague.

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Sprague, M., Michelberger, P., Champion, T. et al. Broadband single-photon-level memory in a hollow-core photonic crystal fibre. Nature Photon 8, 287–291 (2014) doi:10.1038/nphoton.2014.45

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