A single-photon gate A long-standing goal in optics is to produce a solid-state alloptical transistor, in which the transmission of light can be controlled by a single photon that acts as a gate or switch. Sun et al. used a solid-state system comprising a quantum dot embedded in a photonic crystal cavity to show that transmission through the cavity can be controlled with a single photon. The single photon is used to manipulate the occupation of electronic energy levels within the quantum dot, which in turn changes its optical properties. With the gate open, about 28 photons can get through the cavity on average, thus demonstrating single-photon switching and the gain for an optical transistor. Science, this issue p. 57 A solid-state quantum dot memory is used to realize a single-photon switch and optical transistor. Single-photon switches and transistors generate strong photon-photon interactions that are essential for quantum circuits and networks. However, the deterministic control of an optical signal with a single photon requires strong interactions with a quantum memory, which has been challenging to achieve in a solid-state platform. We demonstrate a single-photon switch and transistor enabled by a solid-state quantum memory. Our device consists of a semiconductor spin qubit strongly coupled to a nanophotonic cavity. The spin qubit enables a single 63-picosecond gate photon to switch a signal field containing up to an average of 27.7 photons before the internal state of the device resets. Our results show that semiconductor nanophotonic devices can produce strong and controlled photon-photon interactions that could enable high-bandwidth photonic quantum information processing.

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由固态量子存储器启用的单光子开关和晶体管

单光子门 光学领域的一个长期目标是生产固态全光晶体管，其中光的传输可以由充当门或开关的单个光子控制。孙等人。使用包含嵌入光子晶体腔中的量子点的固态系统来表明可以用单个光子控制通过腔的传输。单光子用于操纵量子点内电子能级的占据，从而改变其光学特性。当门打开时，平均约 28 个光子可以通过腔，从而证明单光子开关和光学晶体管的增益。科学，这个问题 p。57 固态量子点存储器用于实现单光子开关和光学晶体管。单光子开关和晶体管产生强大的光子-光子相互作用，这对量子电路和网络至关重要。然而，单光子光信号的确定性控制需要与量子存储器的强相互作用，这在固态平台中很难实现。我们展示了由固态量子存储器启用的单光子开关和晶体管。我们的设备由一个与纳米光子腔强耦合的半导体自旋量子位组成。自旋量子位使单个 63 皮秒的门光子能够在设备的内部状态重置之前切换包含多达平均 27.7 个光子的信号场。