Wang Chuncheng, Li Xiaokai, Xiao Xiang-Ru, Yang Yizhang, Luo Sizuo, Yu Xitao, Xu Xinpeng, Peng Liang-You, Gong Qihuang, Ding Dajun
Institute of Atomic and Molecular Physics, Jilin University, Changchun 130012, China.
State Key Laboratory for Mesoscopic Physics and Collaborative Innovation Center of Quantum Matter, School of Physics, Peking University, Beijing 100871, China.
Phys Rev Lett. 2019 Jan 11;122(1):013203. doi: 10.1103/PhysRevLett.122.013203.
Elliptically polarized laser pulses (EPLPs) are widely applied in many fields of ultrafast sciences, but the ellipticity (ϵ) has never been in situ measured in the interaction zone of the laser focus. In this Letter, we propose and realize a robust scheme to retrieve the ϵ by temporally overlapping two identical counterrotating EPLPs. The combined linearly electric field is coherently controlled to ionize Xe atoms by varying the phase delay between the two EPLPs. The electron spectra of the above-threshold ionization and the ion yield are sensitively modulated by the phase delay. We demonstrate that these modulations can be used to accurately determine ϵ of the EPLP. We show that the present method is highly reliable and is applicable in a wide range of laser parameters. The accurate retrieval of ϵ offers a better characterization of a laser pulse, promising a more delicate and quantitative control of the subcycle dynamics in many strong field processes.
椭圆偏振激光脉冲（EPLP）在超快科学的许多领域中得到了广泛应用，但椭圆率（ϵ）从未在激光焦点的相互作用区域进行过原位测量。在本信函中，我们提出并实现了一种稳健的方案，通过使两个相同的反向旋转EPLP在时间上重叠来检索ϵ。通过改变两个EPLP之间的相位延迟，对组合的线性电场进行相干控制，以电离Xe原子。阈上电离的电子能谱和离子产率受到相位延迟的灵敏调制。我们证明，这些调制可用于精确确定EPLP的ϵ。我们表明，本方法高度可靠，适用于广泛的激光参数范围。ϵ的精确检索为激光脉冲提供了更好的表征，有望在许多强场过程中对亚周期动力学进行更精细和定量的控制。
