Pradhan S, Jagatap B N
Atomic Physics & Quantum Optics Section, Laser & Plasma Technology Division, Bhabha Atomic Research Centre, Mumbai 400 085, India.
Rev Sci Instrum. 2008 Jan;79(1):013101. doi: 10.1063/1.2827517.
We discuss a simple time of flight technique for measurement of temperature of a cold cloud in a magneto-optical trap (MOT). The technique is based on spatiotemporal fluorescence imaging of the cloud that is allowed to undergo one-dimensional expansion in the presence of the orthogonal two-dimensional configuration of laser beams by temporal modulation of a pair of counterpropagating trapping beams in the MOT. We show that, in the time scale 0< or =t<5 ms, the expansion of the cloud is ballistic and the temperature can be extracted from the time variation of the rms size of the cloud in the expansion direction. The reliability of the technique has been established by comparing the results with release and recapture method, and also by fitting them to the known temperature scaling law.
我们讨论了一种用于测量磁光阱（MOT）中冷原子云温度的简单飞行时间技术。该技术基于对原子云的时空荧光成像，通过对MOT中一对反向传播的捕获光束进行时间调制，使原子云在正交二维激光束配置下进行一维膨胀。我们表明，在0≤t＜5 ms的时间尺度内，原子云的膨胀是弹道式的，并且温度可以从原子云在膨胀方向上的均方根尺寸随时间的变化中提取出来。通过将结果与释放再捕获方法进行比较，并将其拟合到已知的温度标度定律，该技术的可靠性得到了验证。
