Study on impurity separation by laser cooling

在激光冷却技术的基础上，通过使原子动量减速并伴随光子的吸收和发射循环，有望获得几乎为零速度的高密度原子集成体。从光的动力学作用控制原子束运动的角度来看，该技术具有空间控制原子集合与特定激光频率共振的潜力。这作为一种新的杂质分离方法的基本思想是有吸引力的。在本研究中，我们打算展示基于激光冷却技术的杂质分离概念作为一种新的材料精炼方法的可能性。本研究的目的是利用大功率激光二极管开发高质量的光源，将其应用于实际的激光冷却技术和原子速度分布的控制。在本研究中，我们开发了一种可以通过电子输入精确控制频率的大功率单频二极管激光系统。另外，还准备了额外的光源来泵浦从用于激光冷却的吸收和发射循环中排出的原子。通过对原子速度分布的测量，发现原子速度的变化频率与激光扫频频率相同。讨论了激光扫频与冷却距离和温度的关系。此外，我们还讨论了实际杂质分离的前景。

It is expected to obtain a high density atomic ensamble with almost zero velocity by decelerating atomic momentum accompanied with an absorption and emission cycle of a photon based on a laser cooling technique. This technique inherently has a potential to spatially control the atomic ensamble, which is resonant to specific laser frequency from the view point of motion control of an atomic beam by a kinetic action of light. This is attractive as a basic idea of a novel impurity separation method.In this research, we will intend to show the possibility of the impurity separation concept based on the laser cooling technique as one of novel material refining methods. The purposes of this research are development of high quality light source by using a high power laser diode, its application to practical laser cooling technique and control of the atomic velocity distribution.In this research, we developed an high power single frequency diode laser system which frequency can be controlled precisely by an electronic inputs. Additional light source is also prepared to pump the atoms that are expelled from an absorption and emission cycle used for the laser cooling. It was observed that the atomic velocity changed by the same frequency as the laser frequency sweep by measurement of the atomic velocity distribution. We discussed the relationship between the laser frequency sweep, and the cooling distance and the temperature. Moreover, we discussed the prospects of practical impurity separation.