自发Raman散射过程中写激发率对光与原子纠缠源质量的影响

The Influence of Write Excitation Probability on the Quality of Light and Atom Entanglement Source

在87Rb冷原子系综中，利用自发Raman散射过程，实现了光与原子的纠缠。测量了Bell参数S随着写激发率的变化关系，当写激发率增加时，Bell参数s逐渐下降。当写激发率约为1％时，测量了Bell参数S与自旋波存储时间的关系。实验测得Bell参数S会随着存储时间t的增大而减小，在t=80μs的时候S参数的测量值仍然大于2，证明产生的光与原子的纠缠可以保持80μs以上。本文的研究结果为产生高质量的光与原子量子纠缠提供了实验基础。

In the 87 Rb cold atom ensemble, the entanglement of light and atoms was realized during the spontaneous Raman Scattering process. The relationship between the Bell parameter S and the variation of the write excitation probability was measured. When the write excitation probability increased, the Bell parameter S gradually decreased. The relationship between the Bell parameter S and the storage time of the spin wave was measured when the excitation probability was about 1 %. The experimental results showed that the Bell parameter S decreases with the increase of storage time t. When the t= 80 /as is measured, the S parameter value is still greater than 2, which proves that the entanglement between light and atom can be maintained over 80μs. The results of this paper provide an experimental basis for the generation of high quality quantum entanglement of light and atomic.