Morse势阱中子带间的光吸收(英文)

Intersubband Optical Absorption in Morse Quantum Well

研究了Morse势阱中子带间的光吸收 ,并且利用密度矩阵算符理论和迭代方法 ,推导出了线性和三阶非线性子带间的光吸收系数的解析表达式 ,然后以GaAs/AlGaAsMorse势阱为例进行数值计算。结果表明 ,线性吸收系数是正的 ,为总吸收系数作出积极的作用 ,而三阶非线性吸收为负 ,抵消了一部分线性吸收 ,进而得到总的吸收系数 ;吸收系数随着入射光强度的增大而减小 ,即出现吸收饱和现象 ;当势阱参数a增大时 ,吸收系数增大 ,即阱宽较窄时 ,系统吸收的能量较多。若要获得较大的光学吸收系数 ,就要输入较小的光场强度 ,并选择适当的势阱参数a和入射光频率。

Analytic forms of the linear and the third order nonlinear optical intersubband absorption coefficients are obtained for Morse quantum well using density matrix formalism and iterative method. The numerical results are presented for a typical GaAs/AlGaAs Morse quantum well. The results show that the peak absorption is reduced with the incident optical intensity increasing. The total optical absorption enhances with an increase in the parameter a .