School of Physics and Wuhan National Laboratory for Optoelectronics, Huazhong University of Science and Technology, Wuhan 430074, China.
Hubei Key Laboratory of Optical Information and Pattern Recognition, Wuhan Institute of Technology, Wuhan 430205, China.
Phys Rev Lett. 2018 Dec 21;121(25):253203. doi: 10.1103/PhysRevLett.121.253203.
Laser-induced electron tunneling ionization from atoms and molecules plays as the trigger for a broad class of interesting strong-field phenomena in attosecond community. Understanding the time of electron tunneling ionization is vital to achieving the ultimate accuracy in attosecond metrology. We propose a novel attosecond photoelectron interferometer, which is based on the interference of the direct and near-forward rescattering electron wave packets, to determine the time information characterizing the tunneling process. Adding a weak perturbation in orthogonal to the strong fundamental field, the phases of the direct and the near-forward rescattering electron wave packets are modified, leading to the shift of the interferogram in the photoelectron momentum distributions. By analyzing the response of the interferogram to the perturbation, the real part of the ionization time, which denotes the instant when the electron exits the potential barrier, and the associated rescattering time are precisely retrieved. Moreover, the imaginary part of the ionization time, which has been interpreted as a quantity related to electron motion under the potential barrier, is also unambiguously determined.
激光诱导原子和分子的电子隧穿电离在阿秒领域中扮演着引发广泛的有趣强场现象的角色。理解电子隧穿电离的时间对于实现阿秒计量的最高精度至关重要。我们提出了一种新颖的阿秒光电子干涉仪，该干涉仪基于直接和近前向散射电子波包的干涉，以确定表征隧穿过程的时间信息。通过在与强基场正交的方向上添加一个弱扰动，直接和近前向散射电子波包的相位会发生改变，从而导致光电子动量分布中的干涉图发生移动。通过分析干涉图对扰动的响应，可以精确地恢复出电离时间的实部，它表示电子离开势垒的瞬间，以及相关的再散射时间。此外，还可以明确地确定电离时间的虚部，它被解释为与势垒下电子运动相关的一个量。
