光缔合制备超冷铯分子的温度测量

The temperature measurement for the ultracold Cs_2 molecules formed by photoassociation

利用光缔合超冷Cs原子形成超冷Cs2分子,采用多光子电离方法对超冷Cs2分子进行探测,对分子扩散过程中分子密度随时间的演化进行测量,获得了超冷Cs2分子的弛豫曲线.基于一个简单的模型即原子、分子样品的初始分布是位置和速度的高斯函数,通过理论模拟获得了超冷原子、分子样品的温度,测得的原子温度与释放-再俘获方法获得的结果相符合,这种方法避免了通过探测微弱分子荧光来获得分子温度的弊端,可广泛应用于超冷原子、分子样品的温度测量.

Ultracold Cs2 molecules have been formed by photoassociation. Using the multiphoton ionization technique, we measure the time-evolution of expanding process in ultracold Cs2 molecule system and obtain the decay curve of photoionization signals. Based on a simple case, where the initial distribution of atomic or molecular sample is a Gaussian function of position and of velocity, we get the sample＇s temperature by theoretical simulation. The result shows a reasonable agreement with the result of release-recapture method in cold atom sample. This method avoids the disadvantage of detecting the weakly fluorescence and can be widely used for measuring the temperature in cold atom or cold molecule system.