Bai Xiaolu, Su Yingtong, Zhang Jingtao
Opt Express. 2021 Oct 25;29(22):36567-36580. doi: 10.1364/OE.439695.
High-order harmonics generated from Xe driven by counter-rotating two-color driving fields are studied in the frame of a quantum-field scattering theory, and the spin angular momentum transfer is discussed. The driving field is composed by a circularly polarized (CP) mode and an elliptically polarized (EP) mode. We treat the EP mode as a compostition of counter-rotating CP fields of unequal intensity. We use a pair of phased generalized Bessel functions to describe the harmonic generation amplitude, and the conservation of the spin angular momentum during harmonic generation in the two-color field is derived in a solid base and in a straightforward way. The experimentally observed V-type and Λ-type distributions of the harmonic spectra with ellipticity are recovered theoretically. Balance pattern of the spin angular momentum is disclosed substantially.
在量子场散射理论框架下研究了由反向旋转的双色驱动场驱动的氙产生的高次谐波，并讨论了自旋角动量转移。驱动场由圆偏振（CP）模式和椭圆偏振（EP）模式组成。我们将EP模式视为强度不等的反向旋转CP场的组合。我们使用一对相位广义贝塞尔函数来描述谐波产生振幅，并以坚实的基础和直接的方式推导了双色场中谐波产生过程中自旋角动量的守恒。从理论上恢复了实验观察到的具有椭圆率的谐波光谱的V型和Λ型分布。基本上揭示了自旋角动量的平衡模式。
