基片衍射对会聚激光驻波场中原子波包几率密度演化的影响

Effects of Substrate Diffraction on Evolution of the Atom Wave-Packet Probability Density in the Focused Laser Standing Wave

针对激光会聚铬原子沉积实验,运用标量衍射理论,通过数值模拟研究了基片衍射对会聚激光驻波场中原子波包几率密度演化的影响。结果显示基片衍射的影响会随激光中轴线与基片沉积表面距离b0的变化而变化。相对于非衍射情况,衍射效应会提高激光驻波场中会聚平面内原子波包几率密度分布的中心值,同时减小其半峰全宽。当参量b0=-0.2 w0(w0为高斯光束的束腰半径)时,原子波包几率密度的会聚平面和基片沉积表面完全重合。此处,衍射时原子波包几率密度分布的中心值为1.26,其半峰全宽为5.62nm,两者分别为非衍射时的1.1倍和0.94倍。

Based on laser focused Cr atom beam deposition, the simulations of effect of substrate diffraction on evolution of the atom wave-packet probability density in the focused laser standing wave are done with scalar optical diffraction theory. The results show that such effect will vary with parameter b0 which stands for the distance between laser axis and substrate surface which is used for deposition. Compared with non-diffraction, the central value of the probability density distribution of the atom wave packet at the focal plane will be increased and its FWHM will be reduced by substrate diffraction. When bo =- O. 2 wo, the focal plane of the atom wave packet coincides with substrate surface, and the probability density distribution of the atom wave packet has central value of 1.26 with FWHM of 5.62 nm under diffraction, which are 1.1 times and 0.94 times of that without diffraction, respectively.