论文标题
精确的光子回声定时，通过在量子点中进行激子dephasing和rephating的光冻结
Accurate photon echo timing by optical freezing of exciton dephasing and rephasing in quantum dots
论文作者
论文摘要
半导体量子点是极好的候选物，用于通过picsecond Timesscales上激光脉冲对Qubits的超快相干操纵，甚至更快。在不均匀的集合中，由于脱缘量，宏观光学极化迅速衰减，但是，在具有有关相干整体动力学的完整信息的光子回波中，这是可逆的。对于应用，对回声排放时间的控制是必须的。在这里，我们提出了一个新颖的概念来实现这一目标。在两个脉冲光子回声序列中，我们应用了一个额外的谐振控制脉冲，其中有2PI区域。根据其到达的时间，控制在动作过程中放慢了激子合奏的逐渐变化或重新调整。我们证明了自组装（In，GA）为量子点，表明光子回波发射时间可以延迟或降低5 ps，相对于其标称出现时间而无需控制。该多功能方案可用于获得适当量身定制的控制脉冲的时间更长的时间变化。
Semiconductor quantum dots are excellent candidates for ultrafast coherent manipulation of qubits by laser pulses on picosecond timescales or even faster. In inhomogeneous ensembles a macroscopic optical polarization decays rapidly due to dephasing, which, however, is reversible in photon echoes carrying complete information about the coherent ensemble dynamics. Control of the echo emission time is mandatory for applications. Here, we propose a novel concept to reach this goal. In a two-pulse photon echo sequence, we apply an additional resonant control pulse with multiple of 2pi area. Depending on its arrival time, the control slows down dephasing or rephasing of the exciton ensemble during its action. We demonstrate for self-assembled (In,Ga)As quantum dots that the photon echo emission time can be retarded or advanced by 5 ps relative to its nominal appearance time without control. This versatile protocol may be used to obtain significantly longer temporal shifts for suitably tailored control pulses.
