准二维磁光阱中俘获长条形冷原子团

Trapping Cold Atoms in a Quasi-Two Dimension Magnetic-Optical-Trap

介绍了在准二维磁光阱(2D+MOT)中获得超冷原子的实验装置及结果。利用四个矩形线圈、四束椭圆形光斑光束加两束圆形光斑激光束,得到准二维磁光阱,它的特点是势阱为长条形,轴向束缚较小,势阱整体体积比较大,因而可以俘获到数目较多的超冷原子。实验中心附近的磁场梯度为13×10-3Tcm,椭圆型光斑的长短轴为24mm7mm,圆形光斑直径为7mm,光斑功率分别为18mW,6mW。在该势阱中俘获长条形冷原子团的长度为12mm,直径为15mm,原子数为11×107,温度为400μK。

The setup and the experiment of a quasi two dimension magnetic optical trap (MOT) are introduced in the paper. Four rectangular coils combining four elliptical spot beams and two orbicular spot beams are used to obtain a MOT and trap cold atoms. The characteristic of the trap is a pole shape and a bulk trap capacity, so the trap can capture more atoms, atomic cloud. The data of experiment are as following: magnetic gradient of 1.3×10 -3 T/cm, elliptical spot beam of 24 mm/7 mm, orbicular spot beam of 7 mm, and spot power of 18 W, 6 W, respectively. Cold atomic cloud with a 12 mm length, 1.5 mm diameter is obtained in MOT, the atom number is 1.1×10 7, and the temperature is about 400 μK.