采用光致发光方法和纳米光谱成像技术,研究了单个半导体量子点中激发态激子的Rabi振荡。观测了在两个延时位相可控的!/2脉冲激发下,激发态激子数随其量子比特位相旋转而振荡的特性。由实验观测结果分析得知此单个半导体量子点量子比特的自由旋转品质因子约为9.8×104,动力旋转品质因子约为18。讨论了激子从浸润层到量子点的俘获过程对Rabi振荡衰减退相干的影响。简要分析了量子点的激子自旋操控和单光子发射统计特性。

The Rabi oscillations of the exciton of the excited state in single semiconductor quantum dots were investigated by using the photoluminesence and nano-spectroscopy technique. The population on the excited state oscillated as a function of phase angle of the qubit were recorded, in which pulse-pairs with the adjustable time delay were used as the excitation. The quality factors of free rotation is about 9.8×104, and that of the dynamic rotation is about 18 for the single quantum dot excitonic qubit based on the experimental observations, The decoherece mechanism of Rabi oscillation stem from the capture processes from wetting layer to quantum dot is also analyzed. The exciton coherent control and the statistic characteristics of single photon emission in single semiconductor quantum dot are discussed as well.