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在有效质量近似下,利用量子力学密度矩阵理论,从理论上研究了考虑极化子效应后核壳量子点中线性、三阶非线性以及总的光吸收系数在不同条件下随入射光能量变化的关系。通过数值计算,分析了电子-LO声子和电子-IO声子相互作用对ZnS/CdSe柱型核壳结构量子点光吸收系数的影响。结果表明,极化子效应对光吸收系数有很大影响,不同声子模式对光吸收系数影响大小不同。考虑电子-LO声子后,光吸收系数被大大提高。另外,入射光强和弛豫时间对系统的吸收系数也有很大影响。
Under the approximation of effective mass, using the theory of quantum mechanical density matrix, the linear, third-order nonlinearity and the total optical absorption coefficient of the quantum dot under the consideration of the polaron effect are studied theoretically with the change of incident light energy under different conditions Relationship. The effects of the electron-LO phonon and the electron-Io phonon interaction on the optical absorption coefficients of ZnS / CdSe core-shell quantum dots are analyzed numerically. The results show that the polaron effect has a great influence on the light absorption coefficient, and the different phonon modes have different effects on the light absorption coefficient. After considering the electron-LO phonon, the light absorption coefficient is greatly improved. In addition, the incident light intensity and relaxation time on the system’s absorption coefficient also has a great impact.