论文标题
通过光子回波光谱与空间形状激光脉冲观察到的INGAAS量子点中Trions的多个Rabi旋转
Multiple Rabi rotations of trions in InGaAs quantum dots observed by photon echo spectroscopy with spatially shaped laser pulses
论文作者
论文摘要
我们研究了由强度依赖性光子回波产生的狂犬旋转，该旋转是由自组装的Ingaas量子点组合的。为了达到激发合奏中强度的均匀分布，我们引入了皮秒激光脉冲的平坦强度曲线。这使我们能够通过高斯激光轮廓克服狂犬病频率的空间不均匀性施加的狂犬旋转阻尼。使用Photon Echo极化法，我们将相干的光学响应与激子和TRION集合区分开。在这里，我们证明了量子点的照片诱导的充电导致谐振兴奋下中性量子点的数量显着减少，并具有密集的光学脉冲，区域超过$ \fracπ{2} $。当重新聚焦脉冲的面积增加到5.5 $π$时，Trion合奏显示出强大的Rabi旋转。我们通过对激发诱导的脱位，偶极矩的不均匀性以及偶联到声音子的理论建模来分析兔旋转的剩余衰减。后者被确定为导致涉及光脉冲作用过程中光学相干性丧失的主导机制。
We study Rabi rotations arising in intensity-dependent photon echoes from an ensemble of self-assembled InGaAs quantum dots. To achieve a uniform distribution of intensities within the excited ensemble, we introduce flattop intensity profiles of picosecond laser pulses. This allows us to overcome the damping of Rabi rotations imposed by the spatial inhomogeneity of Rabi frequencies by a Gaussian laser profile. Using photon echo polarimetry, we distinguish between the coherent optical responses from exciton and trion ensembles. Here, we demonstrate that a photo-induced charging of the quantum dots leads to a significant reduction of the number of neutral quantum dots under resonant excitation with intensive optical pulses with areas exceeding $\fracπ{2}$. The trion ensemble shows robust Rabi rotations when the area of the refocussing pulse is increased up to 5.5$π$. We analyze the remaining attenuation of Rabi rotations by theoretical modeling of excitation induced dephasing, inhomogeneity of dipole moments, and coupling to acoustic phonons. The latter is identified as the dominating mechanism resulting in a loss of optical coherence during the action of the involved optical pulses.
