论文标题
非脱位极化光子对的Ultrabright Sagnac-type源仅使用现成的光学组件
Ultrabright Sagnac-type source of non-degenerate polarization-entangled photon pairs using only off-the-shelf optical components
论文作者
论文摘要
我们开发了超右手，非脱位，极化输入的光子对的Sagnac型来源，该对同时且紧凑。 We use a $20~\text{mm}$ long PPLN bulk crystal which, upon pumping continuously with $532~\text{nm}$ wavelength, produces polarization-entangled photon-pairs of $785~\text{nm}$ signal and $1651~\text{nm}$ idler wavelengths via the type-0 spontaneous parametric下转换（SPDC）过程。设置中使用的所有光学组件都是现成的组件，可在商业上随时可用；因此，不需要定制设计或昂贵的多波长极化光学器件。同时，在没有任何额外的主动稳定的情况下实现了长期稳定性。由于我们的Sagnac型设计的几何形状。我们还报告了文献中可用的非分类极化光子对的最高亮度之一。 Even with a very low pump power of $0.034~\text{mW}$, we detect a coincidence rate of $(6.96\pm 0.03)\times10^{4}$ entangled pairs/sec/mW (averaged over three polarization-basis measurements: H/V, D/A, and R/L basis).源的亮度计算为$（6.17 \ pm 0.04）\ times10^{6} $纠缠对/sec/mw的信号线宽度为$ 0.4〜 \ text {nm} $。从原始的巧合计数（没有任何背景巧合校正）中，纠缠状态的保真度为$（96.72 \ pm 0.01）\％$，并并发$（94.68 \ pm 0.20）\％$。据报道，贝尔 - 奇克不平等违规为$ s = 2.71 \ pm 0.06 $。
We develop a Sagnac-type source of ultrabright, non-degenerate, polarization-entangled photon pair that is highly stable and compact simultaneously. We use a $20~\text{mm}$ long PPLN bulk crystal which, upon pumping continuously with $532~\text{nm}$ wavelength, produces polarization-entangled photon-pairs of $785~\text{nm}$ signal and $1651~\text{nm}$ idler wavelengths via the type-0 spontaneous parametric down-conversion (SPDC) process. All optical components used in the setup are off-the-shelf components, readily available commercially; hence, no custom-designed or costly multi-wavelength polarization optics are required. At the same time, long-term phase stability is achieved without any additional active stabilization; due to the geometry of our Sagnac-type design. We also report one of the highest brightness of non-degenerate polarization-entangled photon pairs available in the literature. Even with a very low pump power of $0.034~\text{mW}$, we detect a coincidence rate of $(6.96\pm 0.03)\times10^{4}$ entangled pairs/sec/mW (averaged over three polarization-basis measurements: H/V, D/A, and R/L basis). The source's brightness is calculated to be $(6.17\pm 0.04)\times10^{6}$ entangled pairs/sec/mW for the signal line width of $0.4~\text{nm}$. From the raw coincidence counts (without any background coincidence correction), the fidelity of the entangled state is measured to be $(96.72\pm 0.01)\%$ with a concurrence of $(94.68\pm 0.20)\%$. Bell-CHSH inequality violation is reported as $S=2.71\pm 0.06$.
