1112.0900 (D. G. England et al.)

High-Fidelity Polarization Storage in a Gigahertz Bandwidth Quantum
Memory    [PDF]

D. G. England, P. S. Michelberger, T. F. M. Champion, K. F. Reim, K. C. Lee, M. R. Sprague, X. -M. Jin, N. K. Langford, W. S. Kolthammer, J. Nunn, I. A. Walmsley

We demonstrate a dual-rail optical Raman memory inside a polarization
interferometer; this enables us to store polarization-encoded information at
GHz bandwidths in a room-temperature atomic ensemble. By performing full
process tomography on the system we measure up to 97\pm1% process fidelity for
the storage and retrieval process. At longer storage times, the process
fidelity remains high, despite a loss of efficiency. The fidelity is 86\pm4%
for 1.5 \mu s storage time, which is 5,000 times the pulse duration. Hence high
fidelity is combined with a large time-bandwidth product. This high
performance, with an experimentally simple setup, demonstrates the suitability
of the Raman memory for integration into large-scale quantum networks.

View original: http://arxiv.org/abs/1112.0900