Institut für Quantenoptik und Quanteninformation, Österreichische Akademie der Wissenschaften, 6020 Innsbruck, Austria.
Phys Rev Lett. 2013 Jun 28;110(26):263003. doi: 10.1103/PhysRevLett.110.263003. Epub 2013 Jun 25.
We report on Bose-Einstein condensation in a gas of strontium atoms, using laser cooling as the only cooling mechanism. The condensate is formed within a sample that is continuously Doppler cooled to below 1 μK on a narrow-linewidth transition. The critical phase-space density for condensation is reached in a central region of the sample, in which atoms are rendered transparent for laser cooling photons. The density in this region is enhanced by an additional dipole trap potential. Thermal equilibrium between the gas in this central region and the surrounding laser cooled part of the cloud is established by elastic collisions. Condensates of up to 10(5) atoms can be repeatedly formed on a time scale of 100 ms, with prospects for the generation of a continuous atom laser.
我们报告了在使用激光冷却作为唯一冷却机制的情况下，在锶原子气体中实现玻色-爱因斯坦凝聚。该凝聚体是在一个连续多普勒冷却到低于 1 μK 的窄线宽跃迁的样品内形成的。在样品的中心区域达到了凝聚的临界相空间密度，在这个区域中，原子对激光冷却光子变得透明。这个区域的密度通过附加的偶极力阱电势得到增强。通过弹性碰撞，在这个中心区域的气体和云的周围的激光冷却部分之间建立了热平衡。在 100 毫秒的时间尺度上，可以重复形成多达 10(5)个原子的凝聚体，为连续原子激光的产生提供了前景。
