Basic research for the realization of a coherent atomic beam using laser cooling methods

在这项研究项目中，我们开发了利用激光冷却方法实现相干原子束光源的基本技术，这种光源可以发射相位相干物质波。为了实现这种相干原子束光源，我们研制了一台用激光冷却和蒸发冷却两种方法实现原子玻色-爱因斯坦凝聚(BEC)的实验装置。因此，我们开发了一种双MOT(磁光陷阱)系统，它可以在10^~(-11)托尔量级的极低气压下在玻璃池中聚集多达5×10~(-8)个原子。我们还研制了一种用于蒸发冷却的三线圈磁捕获器。这种陷阱可以产生足够高的磁场梯度(~300G/cm)，这是蒸发冷却过程中原子紧密约束所必需的。使用这个磁性陷阱，我们实际上可以捕获和压缩激光冷却的Rb原子。考虑到这些初步实验，如果我们进一步优化装置，采用射频诱导蒸发冷却的方法，我们可以期待用目前的装置实现BBC。我们还讨论了用于相干原子光学的实用相干原子束光源所需的实验方法，并展望了它的未来。

In this research project, we have developed basic techniques for the realization of coherent atomic beam sources, which can emit phase-coherent matter wave, using laser cooling methods. In order to realize such coherent atomic beam sources, we have developed an experimental apparatus for realizing Bose-Einstein condensation (BEC) of ^<87>Rb atoms using both laser cooling and evaporation cooling methods. As a result, we have developed a double-MOT(magnet-optical trap) system which could gather as much as 5×10^8 atoms in a glass cell at the extremely low pressure of the order of 10^<-11> torr. We have also developed a three-coil magnetic trap for the evaporation cooling. This trap can produce enough high magnetic field gradient (〜300 G/cm ) which is required for the tight confinement of atoms during the evaporation cooling. Using this magnetic trap, we could actually trapped and compressed the laser-cooled Rb atoms. Considering these preliminary experiments, we can expect the realization of BBC using the present apparatus if we will further optimize the apparatus and employ a rf-induced evaporation cooling method. We also consider the required experimental methods towards the practical coherent atomic beam sources for coherent atom optics and obtain future prospects for it.