Gerrits Thomas, Stevens Martin J, Baek Burm, Calkins Brice, Lita Adriana, Glancy Scott, Knill Emanuel, Nam Sae Woo, Mirin Richard P, Hadfield Robert H, Bennink Ryan S, Grice Warren P, Dorenbos Sander, Zijlstra Tony, Klapwijk Teun, Zwiller Val
National Institute of Standards and Technology, 325 Broadway, Boulder, Colorado 80305, USA.
Opt Express. 2011 Nov 21;19(24):24434-47. doi: 10.1364/OE.19.024434.
We characterize a periodically poled KTP crystal that produces an entangled, two-mode, squeezed state with orthogonal polarizations, nearly identical, factorizable frequency modes, and few photons in unwanted frequency modes. We focus the pump beam to create a nearly circular joint spectral probability distribution between the two modes. After disentangling the two modes, we observe Hong-Ou-Mandel interference with a raw (background corrected) visibility of 86% (95%) when an 8.6 nm bandwidth spectral filter is applied. We measure second order photon correlations of the entangled and disentangled squeezed states with both superconducting nanowire single-photon detectors and photon-number-resolving transition-edge sensors. Both methods agree and verify that the detected modes contain the desired photon number distributions.
我们对一种周期性极化的磷酸钛氧钾（KTP）晶体进行了表征，该晶体产生了一种具有正交偏振的纠缠双模压缩态，其频率模式几乎相同、可分解，且在不需要的频率模式中光子数很少。我们聚焦泵浦光束以在这两个模式之间创建一个近乎圆形的联合光谱概率分布。在对这两个模式进行解纠缠之后，当应用一个8.6纳米带宽的光谱滤波器时，我们观察到了洪-欧-曼德尔干涉，原始（背景校正后）可见度为86%（95%）。我们使用超导纳米线单光子探测器和光子数分辨过渡边传感器测量了纠缠和解纠缠压缩态的二阶光子关联。两种方法结果一致，并验证了检测到的模式包含所需的光子数分布。
