利用原子芯片上Z形磁阱囚禁中性^(87)Rb原子

A Z-trap in an atom chip for trapping neutral ^(87)Rb atoms

利用解析和数值方法计算了Z形磁阱的囚禁势,发现当囚禁中心和芯片表面距离较远时(该距离和Z形线中部导线的一半长度相差不超过一个量级),势阱的深度不能近似表示成偏置磁场By对应的能量,而要减去囚禁中心的势能高度;而增加By进行磁阱压缩到一定值时,势阱深度反而会下降.此外介绍了原子芯片的制作方法,以及利用原子芯片上Z形磁阱囚禁中性87Rb原子的实验装置和实验过程.最终有2×106个87Rb原子被转移到Z形磁阱中.

Trapping potential of a Z-trap is calculated with analytic and numeric methods.It＇s found that when a trapping center is a little bit far from the chip surface（the distance is about one order of the half length of the Z-wire central part）,the trapping depth is not approximately eqsual to the potential By created by a bias magnetic field,the potential energy at the trapping center should be subtracted from the potential By created by the bias field.On the other hand,if an atom cloud is compressed to a certain extent by increasing By,the trapping depth will be decreased rather than increased.The preparation of the Z-trap in an atom chip,the experimental setup,and the experimental procedure for trapping neutral 87Rb atoms is also introduced.At last we obtained 2×10^6 ^87Rb atoms trapped in the Z-trap.