普适的量子轨迹蒙特卡洛方法在激光与原子相互作用中的应用研究

Application of Generalized Quantum-Trajectory Monte Carlo Method in Studying the Interaction Between Intense Laser Field and Atoms

强场光电离过程自发现以来一直是人们关注的重点,尤其是近年来在实验上观测到了光电子全息现象,人们开始通过各种半经典的理论方法来研究各种新奇结构背后的物理机制.笔者发展了一套普适的量子轨迹蒙特卡洛方法(Generalized Quantum-Trajectory Monte Carlo method,简记为GQTMC),首先通过对实验数据的模拟验证了它的正确性,随后研究了非绝热效应和库仑势效应.随后发现了一种与全息干涉机构不同的干涉现象,消除了近年来有关人们对干涉机制的误解,最后利用相位的相位方法发展了GQTMC,并研究了Freeman共振通道的电离时间差,在Freeman共振现象发现30年之后,首次获得了140 as的Freeman共振的时间信息.

Photoionization under intense laser irradiation is the core fundamental physical phenomenon since it was first observed. Recently, holographic fork structures have been observed in the photoelectron momentum distribution of ionized metastable xenon atoms both in measurement and simulation. Semiclassical models were applied to explain the physical mechanism hidden in those newly founded structures. A generalized quantum-trajectory Monte Carlo（GQTMC）method is presented and there is a good quantitative agreement with the full quantum simulation. The effect of Coulomb potential and the nonadiabatic subcycle ionization on the photoelectron hologram was investigated. Moreover, a novel and universal curved interference structure in the photoelectron momentum distribution was found and the misunderstanding about holographic interference structure within the strong field physics community for a long time was resolved. Most importantly, GQTMC method has been developed with＂phase-of-phase＂and we observed a Freeman resonance time delay in multiphoton ionization of an atom, which is clocked to be 140 attoseconds by using a phase-controlled two-color femtosecond laser pulse.