1维光学粘胶作用下铬原子束空间分布特性

为了研究激光准直场作用下原子束的空间分布状态对纳米光栅沉积制作的影响,基于半经典理论,分析了1维光学粘胶对中性铬原子的作用力特性,利用4阶龙格-库塔数值积分算法对不同激光场强度、不同激光失谐量、不同激光场范围条件下中性铬原子束的空间分布进行了仿真分析。由仿真结果可知,随着激光场强度的增加,原子束的分布向中心区域集中,由于受饱和效应的影响,该种集中的趋势随激光强度的增加而逐渐变缓;同时,当激光失谐量等于原子线宽的一半时,原子束的空间分布最窄。当激光功率为40mW、且失谐量为-2.5MHz时,铬原子束经过1维光学粘胶作用后其空间分布的半峰全宽被压缩为作用前的0.43倍,而原子束密度分布中心值也增大为作用前的1.79倍。结果表明,利用激光准直场的作用可实现原子束空间分布的改善,有利于后续的原子沉积以实现纳米光栅的制作。

Distribution of chromium atoms in 1-D optical molasses

In order to analyze effect of atomic distribution on deposition preparation of nanometer gratings under the action of collimated laser, based on semi-classical theory and Runge-Kutta numerical integration algorithm, the characteristics of dissipative force and the distribution of chromium atoms in 1-D optical molasses was discussed. Then the distribution of chromium atoms was simulated under different laser parameters. The results show that the best distribution appears when the detuning of the laser frequency equals to half of line width of chromium atoms. After the atom beam passing through 1-D optical molasses, its spatial width was suppressed to 0.43 times of that before and the atomic density becomes 1.79 times larger than before, under the condition that laser power equals to 40mW and laser detuning is -2.5MHz. This results show that the atomic distribution can be improved under the action of collimated laser and it’s helpful for the deposition preparation of nanometer gratings.