We interface a spontaneous parametric down conversion (SPDC) crystal and a cold atomic ensemble and demonstrate a highly efficient quantum memory through polarization-encoded single-photon qubits. Specifically, narrowband heralded single photons from a cavity-enhanced SPDC source is stored using cold atomic ensemble, with ~70% storage-and-retrieval efficiency and ~10μs storage time at 50% efficiency. To prevent the degradation after storage, we also manipulate the single-photon wave profile so that the retrieved non-classical nature of single photon is preserved. On the other hand, the dual-rail storage is used for storing polarization-encoded qubits, and the corrected fidelity of flying qubits after storage reaches ~97%. The results pave the way toward large-scale quantum network.
@article{arxiv.2011.14948,
title = {Efficient quantum memory for heralded single photons generated by cavity-enhanced spontaneous parametric downconversion},
author = {Yu-Chih Tseng and Yan-Cheng Wei and Ying-Cheng Chen},
journal= {arXiv preprint arXiv:2011.14948},
year = {2020}
}