初态与纯失相对半导体量子点V型三能级系统拉比振荡的影响

Effect of Initial Conditions and Pure Dephasing on Rabi Oscillation in V-Type Three-Level of Semiconductor Quantum Dots

相干光学操控半导体量子点(SQDs)激子态在量子信息、量子计算中具有很重要的应用。通过对影响量子点(QDs)拉比振荡因素的分析,可获得导致量子点体系退相干的物理机制,这为全光操控半导体量子点体系提供了理论依据。线偏振脉冲激光激发自组织InGaAsQDs,运用系统粒子数主方程并结合光学布洛赫矢量推导了单脉冲激发下V型三能级系统激子动力学方程,利用此方程讨论了初始状态及纯失相对拉比振荡的影响。研究表明,可以通过改变系统初态条件和激发场的偏振角对该体系激子拉比振荡的振幅和频率进行调控,可以用纯失相强度相关衰减因子等效地分析V型三能级体系的退相干特性,从而使相关计算得到了简化。

The coherent optical control of exciton quantum states in semiconductor quantum dots（SQDs）is essential for quantum information and quantum computing.The decoherence physical mechanisms of quantum dots（QDs）can be acquired through analyzing the influence of Rabi oscillation,which provides the theoretic support on all-optical coherent control of multilevel excitonic system.Self-assembled InGaAs QDs is excited by the linear polarized pulse field,the exciton dynamics equations of a three-level V-type system with single pulse are deduced from the master equations of the populations and the Bloch vectors.Based on the exciton dynamics equations,the effect of initial conditions and pure dephasing on Rabi oscillation are discussed.The results show that the amplitude and frequency of Rabi oscillation on exciton can be manipulated by adjusting initial conditions and the polarization angle of excitation field,and the simple intensity dependent damping factor of pure dephasing can well describe the decoherence properties of the V-type three-level system,so that relevant calculation is simplified.