Cho, Y. W.Campbell, G. T.Everett, J. L.Bernu, J.Higginbottom, D. B.Cao, M. T.Geng, J.Robins, N. P.Lam, P. K.Buchler, B. C.2026-01-012026-01-019781943580279ORCID:/0000-0002-2852-7483/work/162369412ORCID:/0000-0002-4421-601X/work/162370931ORCID:/0000-0002-6290-9354/work/163476519https://hdl.handle.net/1885/733799648Quantum memory is an essential element for long distance quantum communi- cation and photonics quantum computation protocols. The practical implementation of such protocols requires an efficient quantum memory with long coherence time. Here, we report a highly efficient coherent optical memory via the gradient echo memory (GEM) technique in cold atoms. The efficiency is as high as 87% with the e-1 coherence time of 1 ms. The ability of quantum storage is verified using heterodyne tomography of small coherent states, showing that our system performs in the quantum regime.enPublisher Copyright: © OSA 2017.201710.1364/CLEO_QELS.2017.FM2E.485020686105