Park Jiho, Kim Heonoh, Moon Han Seb
Department of Physics, Pusan National University, Geumjeong-Gu, Busan 46241, Korea.
Phys Rev Lett. 2019 Apr 12;122(14):143601. doi: 10.1103/PhysRevLett.122.143601.
We report a polarization-entangled photon-pair source obtained via spontaneous four-wave mixing (SFWM) in a Doppler-broadened atomic ensemble of ^{87}Rb atoms using a Sagnac interferometer. Collective two-photon coherence occurs in the Doppler-broadened ladder-type atomic system with bidirectional counterpropagating two-photon resonant pump and coupling fields; hence, polarization-entangled photon pairs are collectively radiated in the phase-matched direction. Without phase stabilization of the interferometry for polarization entanglement, we robustly produce all four Bell states via a polarization Sagnac configuration. The brightness, stability, and temporal purity advantages provided by our polarization-entangled SFWM photon-pair source have very important applications in the context of a practical scalable quantum network.
我们报道了一种通过在使用萨尼亚克干涉仪的多普勒加宽的(^{87}Rb)原子系综中进行自发四波混频（SFWM）获得的偏振纠缠光子对源。在具有双向反向传播的双光子共振泵浦场和耦合场的多普勒加宽阶梯型原子系统中发生集体双光子相干；因此，偏振纠缠光子对在相位匹配方向上集体辐射。在没有用于偏振纠缠的干涉测量相位稳定的情况下，我们通过偏振萨尼亚克配置稳健地产生所有四个贝尔态。我们的偏振纠缠SFWM光子对源所提供的亮度、稳定性和时间纯度优势在实际可扩展量子网络的背景下具有非常重要的应用。
