Operating Spin Echo in the Quantum Regime for an Atomic-Ensemble Quantum Memory

作者：Jun Rui, Yan Jiang, Sheng-Jun Yang, Bo Zhao, Xiao‐Hui Bao, Jian-Wei Pan · 发表于：Physical Review Letters · 年份：2015 · DOI：10.1103/physrevlett.115.133002 · 被引用次数：34 · 研究领域：Quantum optics and atomic interactions、Atomic and Subatomic Physics Research、Cold Atom Physics and Bose-Einstein Condensates

Spin echo is a powerful technique to extend atomic or nuclear coherence times by overcoming the dephasing due to inhomogeneous broadenings. However, there are disputes about the feasibility of applying this technique to an ensemble-based quantum memory at the single-quanta level. In this experimental study, we find that noise due to imperfections of the rephasing pulses has both intense superradiant and weak isotropic parts. By properly arranging the beam directions and optimizing the pulse fidelities, we successfully manage to operate the spin echo technique in the quantum regime by observing nonclassical photon-photon correlations as well as the quantum behavior of retrieved photons. Our work for the first time demonstrates the feasibility of harnessing the spin echo method to extend the lifetime of ensemble-based quantum memories at the single-quanta level.