Polarization-dependent pump-probe studies in atomic fine-structure levels: towards the production of spin-polarized electrons
Polarization-dependent pump-probe studies in atomic fine-structure levels: towards the production of spin-polarized electrons
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原子精细结构水平中的极化相关泵浦探针研究：自旋极化电子的产生
DOI：
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发表时间：
2000
期刊：
影响因子：
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通讯作者：
B. Girard
中科院分区：
文献类型：
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作者：
E. Sokell;S. Zamith;M. Bouchene;B. Girard
在对钾原子4P精细结构态的抽运-探测研究中，观察到了轨道和自旋角动量矢量的进动。飞秒泵浦脉冲使这两种精细结构的成分产生相干叠加。一个延时的探测脉冲在系统被允许自由演化后电离了它。记录在离子信号中的振荡反映了由于自旋-轨道耦合导致的轨道和自旋角动量的取向的演变。这种解释给出了物理洞察的原因观察到的半周期相移时，激光脉冲的相对偏振从平行到垂直的改变。最后，研究表明，系统自旋动量矢量取向的这些变化可以用来产生飞秒尺度的高自旋极化自由电子
The precession of orbital and spin angular momentum vectors has been observed in a pump-probe study of the 4P fine-structure states of atomic potassium. A femtosecond pump pulse prepared a coherent superposition of the two fine-structure components. A time-delayed probe pulse then ionized the system after it had been allowed to evolve freely. Oscillations recorded in the ion signal reflect the evolution of the orientation of the orbital and spin angular momentum due to spin-orbit coupling. This interpretation gives physical insight into the cause of the half-period phase shift observed when the relative polarizations of the laser pulses were changed from parallel to perpendicular. Finally, it is shown that these changes in the orientation of the spin momentum vector of the system can be utilized to produce highly spin-polarized free electrons on the femtosecond scale