我们在^87Rb冷原子系综中进行了关联光子对的产生和测量。通过自发拉曼散射过程,产生了一个Stokes光子和一个原子自旋波激发。利用电磁感应透明效应将存储在原子系综中的自旋波转化为一个anti-Stokes光子。在两相互正交的偏振基下,测量了Stokes光子和anti-Stokes光子之间的交叉关联函数。实验结果表明,交叉关联函数g^2达到^75,表现了强的非经典关联。基于现场可编程门阵列(FPGA)的自编程的多通道符合器被用于光子脉冲信号的采集和逻辑处理,大大提高了偏振关联光子对的产生和测量速度,为以后量子中继技术中的高效信息处理提供了重要基础。
In this paper,we performed the generation and measurement of correlated photon pairs in cold atomic ensemble.A single Stokes photon and one spin-wave excitation were simultaneously created via Spontaneous Raman Scattering(SRS).The spin-wave excitation was then converted into an anti-Stokes photon via an EIT reading process.We measured cross-correlation functions between the Stokes and antiStokes photons for two orthogonal polarizations.The experimental results show that the cross-correlation functions are ~75,which means strong non-classical correlation between the two photons.A selfprogrammed multi-channel coincidence apparatus based on Field-programmable-gate-array(FPGA)was used to sample and take logic operation on the pulsed signals of the photons.This apparatus allows high generation/measurement rate of the photon pairs and provides important technical help for fast information processing in quantum repeater schemes.