磁光阱特性及冷原子集合行为的实验研究

Experimental Study on the Properties of Magneto Optical Trap and the Collective Behaviors of Cold Atoms

磁光阱目前已经成为量子光学领域内的一种强有力的研究工具。在实现了铯磁光阱后，我们通过对实验系统的改进提高了磁光阱的性能，在此基础上对磁光阱中原子数目和密度与磁光阱参数（包括激光光强、失谐以及磁场梯度等）的关系进行了系统的实验研究，结果与我们的理论预计［１］大致符合。同时我们还观察到在调节冷却激光光束准直和补偿地磁场的亥姆霍兹线圈电流过程中出现的冷原子云形状的变化，包括原子云的干涉图样、多亮点原子云、环形原子云、蝴蝶状原子云等，其中不少现象未见报道，对这些现象进行了初步分析。

Magneto Optical Trop (MOT) has become a robust experimental instrument in the field of quantum optics. Based on our improved cesium MOT, we made experimental study of the dependence of the number and density of cold atoms in MOT on the parameters of MOT, e.g., laser intensity, laser detuning and magnetic gradient. The results agreed well with the theoretical predication . We also observed the change of cold atomic clouds when adjusting the alignment of counter propagating laser beams and compensating for the geo magnetic field using three pairs of coils. Interference patterns, multi MOT cold atomic clouds, ring clouds and butterfly alike clouds were observed. After initial and qualitative analysis, we investigated the dynamics processes in MOT and explaind the interesting unreported phenomena.