非对称半导体量子阱中高阶量子关联效应的研究

High-order Quantum Correlation in an Asymmetric Semiconductor Quantum Well

本文在三能级级联结构的非对称半导体量子阱中研究了荧光的高阶量子关联效应.利用三个激光场同时驱动三个偶极允许的跃迁时,研究结果发现强度-强度关联函数和强度-振幅关联函数依赖于驱动场的相对相位及拉比频率.在三个驱动场拉比频率相等的条件下,相对相位为0时,二阶关联呈现出强关联;相位不为0时,二阶关联为一般关联.不仅如此,我们发现改变相位可以调节三阶关联函数时间不对称性程度,相位为π/2或3π/2正时和负时关联函数表现了较好的对称性.另外,我们发现通过调节拉比频率的大小可以实现二阶关联由强关联向一般关联效应转换,三阶强度-幅度关联的值得到极大增强.最后,利用修饰态绘景我们分析了上述现象内在的物理机制为多重量子干涉效应.这些结果可能对于高精度测量和产生单光子源具有潜在的应用价值.

In this paper,the high-order quantum correlation effect is investigated in an asymmetric semiconductor quantum well with a three-level cascade-configuration structure,in which three dipole-allowed transitions are simultaneously driven by three laser fields.We find that the intensity-intensity correlation and intensity-amplitude correlation are strongly dependent on the relative phase and the Rabi frequencies of the driving fields.We assume that all of the Rabi frequencies for the three driven fields are identical.When the relative phase is 0,the intensity-intensity correlation shows strong correlation;otherwise,the normal correlations are obtained.On the other hand,the intensity-amplitude correlations are also modified by the relative phase.When the collective phase is taken asπ/2 or 3π/2,the correlation functions in positive time region and negative time region is approximately symmetrical with each other.In addition,we also find that the intensity-intensity and intensity-amplitude correlations are strongly modified by the Rabi frequencies.When the collective phase is zero,the intensity-intensity correlation can be changed from strong correlation into normal correlation by modifying the Rabi frequency;not only that,the values of third-order correlation can also be greatly enhanced during this process.In order to analyze the internal physics behind the above-mentioned phenomena,we use dressed-state transformation to calculate the decay rates in dressed-state picture.It is explored that there exits two closed decay channels between these dressed states,which lead to the occurrence of multiple quantum interference effects being responsible for the generation of the nonclassical higher-order correlation effects.Also,the dressed-state population is obtained at steady state.The result demonstrates that the quantum interference effects give rise to the coherent population trapping.When the atoms are trapped into the excited state,the anticorrelation is generated.In the other situation,the emitted resonance fluorescence photons show strong correlation when the atoms stay at the ground states.Importantly,the higher-order correlation effect in the semiconductor quantum well may be useful for the high-precision measurement and the detection of single-photon.It also may pave a way to explore the quantum properties of resonance fluorescence.