Strong-field ionization with two-color circularly polarized laser fields
Strong-field ionization with two-color circularly polarized laser fields
复制标题
DOI：
10.1103/physreva.91.031402
复制
发表时间：
2015-03
影响因子：
2.9
通讯作者：
C. Mancuso;D. Hickstein;P. Grychtol;R. Knut;O. Kfir;X. Tong;F. Dollar;D. Zusin;Maithreyi Gopalakrishnan;C. Gentry;E. Turgut;J. Ellis;Ming-Chang Chen;Avner Fleischer;O. Cohen;H. Kapteyn;M. Murnane
中科院分区：
文献类型：
--
作者：
C. Mancuso;D. Hickstein;P. Grychtol;R. Knut;O. Kfir;X. Tong;F. Dollar;D. Zusin;Maithreyi Gopalakrishnan;C. Gentry;E. Turgut;J. Ellis;Ming-Chang Chen;Avner Fleischer;O. Cohen;H. Kapteyn;M. Murnane
强场电离提供了对光与物质相互作用的基本认识，编码了亚˚和亚飞秒尺度上的原子和分子结构。在这个快速通信中，我们探索了一个重要的机制：双色圆偏振激光场的强场电离。与过去使用线性极化驱动器的工作相反，我们探测在二维平面上驱动的电子轨迹，从而将隧道角与重散射角分离开来。这让我们有了几个发现。首先，我们观察到共旋转场的单叶电子分布，而反旋转场的三叶电子分布，为解释圆偏振高谐波光产生的理论模型提供了实验验证。其次，我们发现反向旋转场有明显的电子-离子再散射，而同向旋转场没有。最后，我们表明，重新散射的电子与直接电离的电子分离得很好，与线性极化场中看到的类似低能结构形成鲜明对比。这些发现有助于克服如何在强场电离中解耦隧道和重散射步骤的长期问题，这将使原子和分子结构的新动态探针成为可能。
Strong-field ionization provides fundamental insight into light-matter interactions, encoding the structure of atoms and molecules on the sub˚¨ and subfemtosecond scales. In this Rapid Communication, we explore an important regime: strong-field ionization by two-color circularly polarized laser fields. In contrast to past work using linearly polarized drivers, we probe electron trajectories that are driven in a two-dimensional plane, thus separating the tunneling angle from the rescattering angle. This allows us to make several findings. First, we observe a single-lobed electron distribution for co-rotating fields, and a three-lobed distribution for counter-rotating fields, providing experimental validation of the theoretical model explaining the generation of circularly polarized high harmonic light. Second, we discover that there is significant electron-ion rescattering using counter-rotating fields, but not with co-rotating fields. Finally, we show that the rescattered electrons are well separated from the directly ionized electrons, in striking contrast to similar low-energy structures seen with linearly polarized fields. These findings help overcome the long-standing problem of how to decouple the tunneling and rescattering steps in strong-field ionization, which will enable new dynamic probes of atomic and molecular structure.