We have performed a proof-of-principle experiment in which qubits encoded in the polarization states of single-photons from a parametric down-conversion source were coherently stored and read-out from a quantum memory device. The memory device utilized a simple free-space storage loop, providing a cyclical read-out that could be synchronized with the cycle time of a quantum computer. The coherence of the photonic qubits was maintained during switching operations by using a high-speed polarizing Sagnac interferometer switch.
@article{arxiv.quant-ph/0207041,
title = {Cyclical Quantum Memory for Photonic Qubits},
author = {T. B. Pittman and J. D. Franson},
journal= {arXiv preprint arXiv:quant-ph/0207041},
year = {2009}
}