计及声子辅助跃迁的单量子点中的非线性法拉第偏转  

Nonlinear Faraday rotation in a single semiconductor quantum dot with phonon-assisted transition

作　　者：佘彦超[1] 张蔚曦[1] 李勇[1] 肖政国 SHE Yan-Chao;ZHANG Wei-Xi;LI Yong;XIAO Zheng-Guo(Department of Physics and Electronic Engineering,Tongren University,Tongren 554300,China)

机构地区：[1]铜仁学院物理与电子工程系

出　　处：《原子与分子物理学报》2019年第4期621-628,共8页Journal of Atomic and Molecular Physics

基　　金：国家自然科学基金(11747168);贵州省教育厅自然科学研究项目(KY(2015)384和KY(2015)446);贵州省科技厅联合基金(LH[2015]7228);铜仁学院博士启动课题(trxyDH1529)

摘　　要：利用一束弱线性π偏振探测光在与其平行的磁场作用下所形成的两偏振分量,在半导体单量子点中考虑声子辅助跃迁去构建环形四能级电磁感应透明介质模型.利用多重尺度法,解析研究发现:仅考虑系统的线性效应,随着耦合光强度的增加,介质对探测光的吸收迅速减少,形成透明窗口,并且透明窗口的宽度随之增大;进一步地,在相同的外加磁场下探测光的非线性法拉第偏转方向与线性法拉第偏转相反,且偏转角更大.随着声子辅助跃迁强度的增加,线性和非线性法拉第偏转角都会逐渐变小,并且非线性法拉第偏转角减小的更多.这说明系统中的声子辅助跃迁能有效地调制探测光的法拉第偏转.我们的研究可能对于弱光条件下的光信息处理和传输具有潜在的应用价值.In this paper,with considering that a weak,π-linear-polarized probe field can form left-and right-polarized components under the control of the parallel magnetic field,a theory model of the four-level type semiconductor quantum dot system under the mechanism of electromagnetically induced transparency(EIT)is proposed.The linear optical absorption properties and Faraday rotation in this system are analytically studied with the phonon-assisted transition(PAT).By using the multiple-scale method,it is found that the absorption of the probe optical field decreases rapidly to form an electromagnetically induced transparency(EIT)window,and the width of the EIT window becomes wider with the strength of the coupling field increasing.Meanwhile,the results show that for the same magnetic field the nonlinear Faraday rotation direction is opposite to linear Faraday rotation,and its rotation angle grows bigger than that of linear Faraday rotation.Furthermore,we found that both of the nonlinear and linear rotation angles decreased and the nonlinear one decreases faster with the strength of PAT increasing.These results mean that the Faraday rotation of the single quantum dot can be controlled by the PAT effect.

关 键 词：声子辅助跃迁 电磁感应透明 法拉第偏转 半导体量子点 

分 类 号：O431[机械工程—光学工程] O437[理学—光学]