冷原子系综中两正交光场偏振模高效率存储的实验研究  

Highly-efficient optical storage of two orthogonal polarization modes in a cold atom ensemble

作　　者：温亚飞 王圣智 徐忠孝[1,2] 李淑静 王海[1,2] 

机构地区：[1]山西大学光电研究所,量子光学与光量子器件国家重点实验室,太原030006 [2]极端光学协同创新中心,太原030006

出　　处：《物理学报》2018年第1期101-107,共7页Acta Physica Sinica

基　　金：国家重点研发计划(批准号：2016YFA0301402); 国家自然科学基金(批准号：11475109,11274211)、国家自然科学基金青年科学基金(批准号：11604191); 山西省应用基础研究计划(批准号：201601D202007); 山西省“1331工程”重点学科建设计划经费(批准号：1331KSC)资助的课题

摘　　要：高效率光量子信息存储是可扩展光量子信息处理的一个重要工具.本文对一个冷原子系综中两正交光场偏振模的高效率存储进行了实验研究.通过在雪茄型冷原子系统上施加一个中等强度的磁场,消除了原子Zeeman子能级的简并性,从而使磁敏感自旋波从电磁感应透明系统中被移出,由此完成了两正交光场偏振模高效率、长寿命的量子存储.实验测量了两偏振模存储效率与存储时间以及实验重复频率的关系,结果表明,随着重复频率的增加,存储效率逐渐降低,在10 Hz时,测量得到两偏振模存储效率为30%,同时存储寿命达到3 ms.测量结果为偏振纠缠在冷原子系统中的存储提供了重要的实验基础.Optical quantum memory plays an important role in scaling-up linear optical quantum computations and longdistance quantum communication. For effectively realizing such tasks, a long-lived and highly-efficient quantum memory is needed. The dynamic electromagnetically-induced-transparency（EIT） process can be used for completing an absorptive storage scheme in an atomic ensemble. In such a process, the quantum states of coming single photons can be coherently transformed into spin waves associated with coherences between atomic ground levels via switching off controlling light beam. For storing a single-mode optical signal, a pair of ground levels is involved. While for storing an optical polarization qubit, i.e., two orthogonal polarization modes, the coherence between two pairs of ground levels will be involved. Also, to obtain a high efficiency in the EIT optical storage, the optical-depth of the cold ensemble should be high. For prolonging the coherent time of the spin waves stored in atomic ensemble, decoherence between spin waves due to atomic motion and non-uniform Zeeman shift of ground levels should be effectively suppressed. Recently, a long-lived and highly-efficient optical quantum memory for single-mode storage in a high-optical-depth cold atom ensemble has been experimentally demonstrated via the gradient echo memory scheme（2016 Optical 3 100）. While, for the optical polarization qubit storage, a long lifetime（in ms） and high-fidelity EIT storage experiment has been achieved by our group, but the storage efficiency in the experiment is very low（8%） due to lower optical depth of the cold ensemble（2013 Phys. Rev. Lett. 111240503）. The storage efficiency in long-lived storage of two orthogonal polarization modes still needs further improving.Here in this paper we demonstrate an experiment of long-lived and highly-efficient storage of two optical orthogonal polarization modes in a high optical-depth cold atomic ensemble via dynamic EIT process. For achieving a long lifetime in the stora

关 键 词：高效率 长寿命 电磁感应透明 

分 类 号：O431.2[机械工程—光学工程]