基于磁悬浮大体积交叉光学偶极阱的Dimple光阱装载研究  

Inverstigation on loading of the Dimple optical trap based on a magnetically levitated large-volume crossed optical dipole trap

作　　者：王晓锋[1] 李玉清[1] 冯国胜[1] 武寄洲[1] 马杰[1] 肖连团[1] 贾锁堂[1] 

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

出　　处：《物理学报》2016年第8期113-122,共10页Acta Physica Sinica

基　　金：国家重点基础研究发展计划(批准号:2012CB921603);教育部长江学者和创新团队发展计划(批准号:IRT13076)、教育部新教师基金(批准号:20131401120012);国家自然科学基金重大研究计划(批准号:91436108)、国家自然科学基金(批准号:61378014,61308023,61378015,11434007);山西省优秀青年学术带头人和山西省青年科技研究基金(批准号:2013021005-1)资助的课题~~

摘　　要：三维拉曼边带冷却后的铯原子样品装载于一个磁悬浮的大体积交叉光学偶极阱中,继续加载一个小体积的光学偶极阱后,实现了Dimple光学偶极阱对铯原子的高效装载.对不同磁场下磁悬浮大体积光阱的有效装载势能进行理论分析与实验测量,得出最优化的梯度磁场和均匀偏置磁场,获得了基于磁悬浮大体积光阱的Dimple光学偶极阱的装载势能曲线,实现了Dimple光学偶极阱对经拉曼边带冷却后俘获在磁悬浮的大体积光阱中的铯原子样品的有效装载.比较了Dimple光学偶极阱分别从拉曼边带冷却、大体积的交叉光阱和消除反俘获势后的磁悬浮大体积光阱装载的结果,将俘获在磁悬浮大体积光阱中的铯原子样品装载到Dimple光学偶极阱,铯原子样品的密度提高了约15倍.Optical trapping techniques and the ability to tune the atomic interactions both have made the unprecedented progress in the quantum gas research field. The major advantage of the optical trap is that the atoms are likely to be trapped at various sub-levels of the electronic ground state and the interaction strength can be controlled by Feshbach resonance. Optical trapping methods in combination with magnetic tuning of the scattering properties directly lead to the experimental achievements of Bose-Einstein condensation（BEC） of Cesium, which at first failed by using magnetic trapping approaches due to the large inelastic collision rate. The rapid loss of cesium atoms due to the inelastic two-body collisions greatly suppresses the efficient evaporative cooling to obtain a condensate.For optical production of cesium atomic BEC, it is necessary to prepare a large number of Cs atoms at specified state in an optical trap for condensation, especially for an efficient forced evaporation cooling. In this paper, we demonstrateour research on enhancing the loading rate of the atoms by using a Dimple trap combined with a large-volume optical dipole trap（reservoir trap）. In our work, the cold cesium atoms are prepared by a three-dimensional degenerated Raman sideband cooling, and then loaded into a large-volume crossed dipole trap by using the magnetic levitation technique. Effective load of the Dimple optical trap is realized by superposing the small-volume Dimple trap on the center of the large-volume optical trap. The theoretical analyses are performed for the magnetically levitated largevolume crossed dipole trap in variable magnetic field gradients and uniform bias fields. Optimal experimental values are acquired accordingly. The combined potential curve of the Dimple trap, which is superimposed on the magnetically levitated large-volume dipole trap, is also given. The loading of precooled atoms from Raman sideband cooling into the magnetically levitated large-volume optical trap is measured in variable magnetic

关 键 词：磁悬浮 拉曼边带冷却 Dimple光学偶极阱 

分 类 号：O562[理学—原子与分子物理]