Dependence of femtosecond time-resolved magneto-optical Kerr rotation on the direction of polarization of the probe beam  

作　　者：FENG XiaoBo LI Yan QIN Yi XIAO YunFeng YANG Hong GONG QiHuang 

机构地区：[1]State Key Laboratory for Mesoscopic Physics and Department of Physics, Peking University, Beijing 100871, China

出　　处：《Science China(Physics,Mechanics & Astronomy)》2011年第8期1411-1415,共5页中国科学：物理学、力学、天文学（英文版）

基　　金：supported by the National Natural Science Foundation of China (Grant Nos. 10821062 and 11074013)

摘　　要：We demonstrate that the femtosecond time-resolved magneto-optical Kerr rotation oscillates with the direction of polarization of the probe beam when a sample of Al0.25Ga0.75As/GaAs multi-quantum wells is excited by a circularly polarized pump and detected by a linearly polarized probe at wavelengths from 800 to 830 nm. Analytical expressions are derived to explain the mechanism, which is in good agreement with the numerical computation and the experimental data. The results suggest that the Kerr signal can be enhanced by choosing an optimal direction of polarization, which is of benefit to the measurement of the weak Kerr rotation.We demonstrate that the femtosecond time-resolved magneto-optical Kerr rotation oscillates with the direction of polarization of the probe beam when a sample of Al0.25Ga0.75As/GaAs multi-quantum wells is excited by a circularly polarized pump and detected by a linearly polarized probe at wavelengths from 800 to 830 nm. Analytical expressions are derived to explain the mechanism, which is in good agreement with the numerical computation and the experimental data. The results suggest that the Kerr signal can be enhanced by choosing an optimal direction of polarization, which is of benefit to the measurement of the weak Kerr rotation.

关 键 词：time-resolved Kerr rotation spin dynamics direction of polarization 

分 类 号：O436.3[机械工程—光学工程] TQ610.7[理学—光学]