High-Fidelity Polarization Storage in a Gigahertz Bandwidth Quantum Memory

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 t...

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Bibliographic Details
Main Authors: England, D, Michelberger, P, Champion, T, Reim, K, Lee, K, Sprague, MR, Jin, X, Langford, N, Kolthammer, W, Nunn, J, Walmsley, I
Format: Journal article
Language:English
Published: 2011
Description
Summary: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.