用于研制纳米长度标准的激光准直原子技术研究

亚百纳米长度计量标准是实现在纳米尺度精确计量的关键器件。我们课题组已利用原子光刻技术研制出了周期为2130.1nm 的光栅，该光栅的周期对应于原子的跃迁频率，具有直接溯源性和高的精确度。理论与实验数据表明原子的横向准直效果是影响光栅对比度的主要因素。因此，文中将介绍几种原子准直技术的优化与估算方法。利用刀口技术分析了激光多普勒准直原子技术的效果。利用CCD 收集的荧光分析原子的发散角与横向温度，并考虑与分析了吸收率对测量结果的影响。原子的发散角为0.544 mrad，对应的横向温度为343.8 K。文中还分析了各种实验参数对准直效果的影响。

Collimation of atomic beam for the fabrication of nano-scale length standards

To meet the requirement of Nano-scale dimensional metrology, length standards with features below 100 nanometers were indispensible instruments. The length standards with periodic length of 213 0.1 nm were successfully fabricated through atom lithography, which was connected to atomic transition frequency and thus retraceable to a constant measured with highly accuracy. For further improvement of the quality of these standards, the evaluation and optimization of collimating the atomic beam were described in this article. A knife-edge was settled to cut the atomic beam collimated by the laser Doppler cooling. The fluorescence of the beam was collected to calculate its angular distribution and equilibrium transverse temperature. The stimulated absorption rate was considered and discussed. Full angular width at half maximum as small as 0.544 mrad was observed, corresponding to temperature of 343.8 K. Several angular distributions were measured by changing the laser characteristics to optimize the collimation.