高密度冷原子云辐射陷获效应造成的荧光减弱现象

实验测量了磁光阱的磁场关断之后的荧光变化，观察到几十ms量级的荧光上升过程. 根据实验条件进行分析，在高密度冷原子云中辐射陷获效应造成额外的非相干抽运光场是造成磁光陷阱紧束缚状态下荧光减弱的原因. 同时还进行了简单的数值模拟，结果表明只有考虑到散射光场的频率重分布效应，计算结果方能与实验符合. 关键词： 冷原子云 辐射陷获 频率重分布

Fluorescence weakening due to radiation trapping in a high density cold-atom cloud

We have measured the change of fluorescence from cold ⁸⁷Rb atoms after magnetic field of the magneto-optic trap is turn off. A rise in fluorescence within several tens of milliseconds was observed. Analyzing this phenomenon in connection with the experimental conditions, we found that incoherent pumping field due to radiation trapping in the high density cold-atom cloud was the reason of fluorescence weakening under tight confinement by the magneto-optic trap. We have also performed a simple numerical simulation, which indicated that the calculations agree with experimental results only when the effect of frequency redistribution of scattered light is taken into account.