利用原子系综中光存储读出信号对环境磁场补偿的方法研究  

Study on Environmental Magnetic Field Compensation Using Optical Memory Readout Signal in Atomic Ensemble

作　　者：刘超[1,2] 李雅 刘海龙 高雁[1,2] 孙灿 李淑静[1,2] 王海 LIU Chao;LI Ya;LIU Hai-long;GAO Yan;SUN Can;LI Shu-jing;WANG Hai(State Key Laboratory of Quantum Optics and Quantum Optical Devices,Institute of Optoelectronics,Shanxi University,Taiyuan 030006,China;Extreme Optics Collaborative Innovation Center,Shanxi University,Taiyuan 030006,China)

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,山西太原030006 [2]山西大学极端光学协同创新中心,山西太原030006

出　　处：《量子光学学报》2021年第4期288-294,共7页Journal of Quantum Optics

基　　金：国家重点基础研究发展计划(2016YFA0301402);国家自然科学基金(11475109,11974228,11604191);山西省“1331工程”重点学科建设计划(133KSC)。

摘　　要：在光与原子纠缠量子界面的建立过程中,环境磁场带来的干扰不可忽视,因此需要对环境磁场进行严格补偿。在多能级结构的原子系综中,通过自发拉曼过程会产生多个原子自旋波,在外界磁场的干扰下,这些自旋波的读出效率会随着存储时间发生振荡。通过对环境磁场的补偿可以有效消除振荡,目前大量补偿磁场的工作依赖于高精度的磁场测量仪器,我们利用读出信号随磁场的变化而变化的特性,采用了利用读出效率对环境磁场补偿的方法研究。本文在磁光阱(MOT)的周围安装了三对线圈分三个方向对磁场噪声进行补偿。通过调节线圈的电流改变磁场,使得读出效率由于磁场的存在而干涉相消需要的时间不断增大,直至超过磁场为0时的存储寿命,出现的振荡消失即对环境磁场完成了补偿。由于人为操作误差以及不稳定因素带来的影响,使用高精度磁场测量仪器对磁场进行精确的补偿是不可能的,鉴于此,上述以原子为参照的方法可以更精确地补偿环境磁场。本文的工作为有效完成量子纠缠交换提供了帮助。Compensating the environmental magnetic field strictly is necessary for the interference caused by environmental magnetic fields which cannot be ignored disturbing the spin waves for quantum memory in the process of establishing the interface between light and atom.The read efficiency of multiple spin waves generated through the spontaneous Raman process will oscillate with storage time under the interference of external magnetic field in the atomic ensemble with multi-level structure.The oscillation of the readout efficiency with the storage time of magnetic field could be eliminated by magnetic compensation,and a large amount of compensation depends on the high precision magnetic field measuring instruments till now.We use multiple level atom ensemble of the Raman processes occurring in the spin wave.The characteristics of the readout signal vary with magnetic field,carrying out the method of using reading efficiency of environmental magnetic field compensation research.Compensating the magnetic field noise in three directions by adjusting the current of the three pairs of coils installed around the magnetic-opticaltrap(MOT),the interference disappearing time influenced by the magnetic field of the readout efficiency increases continuously until the storage life exceeds the storage life of zero magnetic,and the oscillation disappearance is the symbol of completing the compensation for the environmental magnetic field.Accurately compensating the magnetic of environmental at the location of the atom to zero is impossible with the residual of measurement and adjustment due to human operation error and external unstable factors by gauss meter.In view of the fact,the above method using atoms as reference frame can compensate the environmental magnetic field more accurately and is helpful for the quantum entanglement distribution efficiently.

关 键 词：原子自旋波 读出效率 存储寿命 环境磁场 

分 类 号：O431[机械工程—光学工程]