Pursley B C, Carter S G, Yakes M K, Bracker A S, Gammon D
NRC Research Associate residing at the Naval Research Laboratory, Washington, DC, 20375, USA.
Naval Research Laboratory, Washington, DC, 20375, USA.
Nat Commun. 2018 Jan 9;9(1):115. doi: 10.1038/s41467-017-02552-7.
Quantum dots (QDs) are an excellent single-photon source that can be combined with a spin quantum memory. Many quantum technologies require increased control over the characteristics of emitted photons. A powerful approach is to trigger coherent Raman photons from QDs with a Λ energy-level system, such as the spin singlet-triplet system in two coupled QDs. The temporal and spectral behavior of single Raman photons can be varied simply by modifying the excitation source. Here, we demonstrate control of the single-photon pulse shape in a solid-state system on a timescale much shorter than the radiative lifetime, in addition to control of the frequency and bandwidth. We achieve a photon pulse width of 80 ps-an order of magnitude shorter than the exciton lifetime. Possible applications include time-bin encoding of quantum information, matching photons from different sources, and efficient single-photon transfer in a quantum network.
量子点（QDs）是一种出色的单光子源，可与自旋量子存储器相结合。许多量子技术都需要对发射光子的特性进行更强的控制。一种有效的方法是利用Λ能级系统（如两个耦合量子点中的自旋单重态-三重态系统）从量子点触发相干拉曼光子。只需改变激发源，就能改变单个拉曼光子的时间和光谱行为。在此，我们展示了在固态系统中，除了控制频率和带宽外，还能在比辐射寿命短得多的时间尺度上控制单光子脉冲形状。我们实现了80皮秒的光子脉冲宽度，比激子寿命短一个数量级。可能的应用包括量子信息的时间槽编码、匹配来自不同源的光子以及量子网络中的高效单光子传输。
