激光准直铬原子束三维仿真分析

为了获得高准直度的中性铬原子束，设计了一个由三组激光束组成的激光准直场对高温铬原子束进行准直。应用蒙特卡罗随机方法模拟实际状态下原子的初始状态，更好地体现了实际状态中原子运动的不确定性以及原子同位素对实验的影响。以原子在激光准直场中的受力情况为依据，定量分析了实际状态中性铬原子束在激光准直场作用下的运动特性，及其在三维空间的运动轨迹和原子落点状态的三维分布。研究显示，经准直后铬原子束在 x 方向最大发散角减小至1．5 mrad，y 方向最大发散角减小至1．6 mrad，且原子通量提高至准直前的两倍。研究结果不仅为实验提供了更详尽的数据资料，更为后续制作更精确的纳米光栅和纳米点提供了更理想的冷原子束。

3 D simulation analysis of laser collimating Cr atomic beam

In order to acquire high collimating neutral Cr atomic beam,a laser collimating field is designed which is composed of three groups of laser beams to collimate high temperature Cr atomic beam.To reflect better the uncertainty of atomic motion in actual status and the influence of atomic isotopes on experiments,Monte Carlo random method is used to simulate the atomic initial state in the actual state.Based on stress distribution of atoms in the laser collimating field,motion characteristics of neutral Cr atomic beam in the actual state are quantitatively analyzed under the laser collimating field,and this motion path in the three dimensional space and three dimensional distribution of atomic landing point status are analyzed.The results show that the maximum divergency angle decreases to 1.5 mrad in x direction and decreases to 1.6 mrad in y direction after collimating Cr atomic beam,and atomic flux increases twice.Study results provide more detailed data for experiment and more ideal cold atomic beam for further more precise nanometer grating and nanodots.