The long-range interaction between Rydberg-excited atoms endows a medium with large optical nonlinearity. Here, we demonstrate an optical switch to operate on a single photon from an entangled photon pair under a Rydberg electromagnetically induced transparency configuration. With the presence of the Rydberg blockade effect, we switch on a gate field to make the atomic medium nontransparent thereby absorbing the single photon emitted from another atomic ensemble via the spontaneous four-wave mixing process. In contrast to the case without a gate field, more than 50% of the photons sent to the switch are blocked, and finally achieve an effective single-photon switch. There are on average 1–2 gate photons per effective blockade sphere in one gate pulse. This switching effect on a single entangled photon depends on the principal quantum number and the photon number of the gate field. Our experimental progress is significant in the quantum information process especially in controlling the interaction between Rydberg atoms and entangled photon pairs.

雷德堡激发的原子之间的远程相互作用赋予了一种具有大的光学非线性的介质。在这里，我们演示了一种光学开关，该光学开关可以在Rydberg电磁感应的透明结构下，对来自纠缠的光子对的单个光子进行操作。由于存在里德堡阻挡效应，我们打开门磁场使原子介质不透明，从而通过自发的四波混合过程吸收从另一个原子团发出的单个光子。与没有门场的情况相比，发送到开关的光子有超过50％被阻塞，最终实现了有效的单光子开关。一个门脉冲中，每个有效的阻塞球平均有1-2个门光子。对单个纠缠光子的这种转换效应取决于栅场的主量子数和光子数。我们的实验进展在量子信息过程中意义重大，尤其是在控制Rydberg原子与纠缠的光子对之间的相互作用方面。