铬原子束的激光冷却机制分析

Laser cooling mechanism of Chromium atomic beam

利用近共振激光驻波场操纵中性原子实现纳米量级条纹沉积技术,是一种新型的研制纳米结构长度标准传递的方法,其中原子束的横向激光冷却是影响原子光刻技术的一个关键问题。以铬原子为例,对原子与激光冷却场的相互作用过程进行了分析和研究,并基于半经典理论的多普勒和亚多普勒激光冷却力的特性,给出了与冷却力相关参数的分析。仿真结果表明,在多普勒激光冷却力的作用下,铬原子束能够达到120μk的多普勒冷却极限,相应的横向速度为13.87 cm/s.

The technology of laser-focused atomic deposition can be used to develop the nanostructure transfer standard of length. The atomic laser cooling is a key technique in atom lithography. A theoretical investigation of chromium atomic beam in optical traps is reported in this paper. The Doppler and sub-Doppler laser cooling forces are discussed and some characteristics of these forces are shown based on the semi-classical theory. The simulation results indicate that the atomic beam can be collimated by these laser cooling forces, especially by sub-Doppler laser cooling force and can reach the Doppler limit 120 μk,relative horizontal-speed 13.87 cm/s.