提出了一种用一对金属平板电容器和4根半埋入绝缘介质的杆电极组成的用于囚禁处于弱场搜寻态的冷极性分子的静电表面阱方案。用有限元软件计算了单阱囚禁时的空间电场分布, 发现芯片表面上方2.2 mm左右形成了一个三维封闭的静电阱。选用重氨(ND3)分子作为测试分子, 用经典的蒙特卡罗方法模拟了ND3分子被装载和囚禁的动力学过程。模拟结果表明, 当ND3分子束中心速度为13 m/s、装载时刻为0.576 ms时, 最大装载效率可达53%, 被囚禁的冷极性分子的温度约为35 mK; 如果继续增大平板电极的电压, 则原先的单阱将对称分裂为两个阱, 两个阱中的分子数目比为1∶1; 通过改变中间两个杆电极的电压, 可实现非对称分裂, 以此来调节两阱中囚禁分子数目比; 可实现在0%~100%范围内左阱和右阱的分子数目占总分子数目的比例的调节。该方案为进一步研究三维囚禁型冷极性分子静电表面干涉仪打下基础, 对于精密测量和研究物质波干涉有着重要的意义。

An electrostatic surface well scheme for trapping cold polar molecules in week-field-seeking state is proposed, and the electrostatic surface well is composed of a pair of metallic parallel-plate capacitors and four charged rods part-embedded in insulating medium. Spatial distribution of electric field is calculated with the finite element software in the trapping process in the case of single well trapping, and we find that a three-dimensional enclosed electrostatic well which is 2.2 mm above the chip surface is obtained. Ammonia molecule (ND3) is chosen as the test molecule and the dynamic processes of loading and trapping are simulated by the classical Monte Carlo method. Simulation results indicate that when the velocity of ND3 molecular beam center is 13 m/s and the loading time is 0.576 ms, the loading efficiency as high as 53% can be obtained, and the corresponding temperature of trapping cold molecules is about 35 mK. When the voltage applied to the flat electrode is increasing, the single well will splits into two symmetrical wells, and the ratio of the molecules in the two wells is 1∶1. Unsymmetrical split of the single well can be realized when we adjust the voltages of the two pole electrodes in the middle, and the ratio of trapping molecules in the two wells can be controlled. The ratio of molecules in the left well or the right well to the total molecules can be adjusted from 0% to 100%. This method lays a foundation for the three-dimensional trapping cold polar molecule electrostatic surface interferometer, and it is helpful for the studies about precision measurement and matter wave interference.