Photon echo is a fundamental tool for the manipulation of electromagnetic fields. Unavoidable spontaneous emission noise is generated in this process due to the strong rephasing pulse, which limits the achievable signal-to-noise ratio and represents a fundamental obstacle towards their applications in the quantum regime. Here we propose a noiseless photon-echo protocol based on a four-level atomic system. We implement this protocol in a Eu3+:Y2SiO5bcrystal to serve as an optical quantum memory. A storage fidelity of 0.952 is obtained for time-bin qubits encoded with single-photon-level coherent pulses, which is far beyond the maximal fidelity achievable using the classical measure-and-prepare strategy. In this work, the demonstrated noiseless photon-echo quantum memory features spin-wave storage, easy operation and high storage fidelity, which should be easily extended to other physical systems.
@article{arxiv.2107.09857,
title = {Elimination of Noise in Optically Rephased Photon Echoes},
author = {You-Zhi Ma and Ming Jin and Duo-Lun Chen and Zong-Quan Zhou and Chuan-Feng Li and Guang-Can Guo},
journal= {arXiv preprint arXiv:2107.09857},
year = {2021}
}