基于束缚态的强场超快动力学过程研究

The research of ultrafast bound-state dynamics is becoming a hot topic in strong field ultrafast physics with the developments of attosecond pulse and wavelength-widely-tunable Free Electron Laser (FEL) technologies. Aiming on this frontier research field, in this project, we propose researches on mechanisms and corresponding applications of the strong field ultrafast dynamics related to bound states. Theoretical analysis method and numerical simulation code for describing strong field ultrafast bound-state dynamics, especially including propagation effects excited by attosecond pulse, will be developed. By analyzing new effects in the momentum spectrum and the high-order harmonic generation spectrum from different initial bound states, we will try to find clear influences of subtle effects such as initial momentum distribution et al. on wave packet dynamics and quantum interferences of bound states. By studying the attosecond transient absorption spectrum with the spatiotemporal coupling, the underlying physical mechanisms of sub-cycle ultrafast transient optical effects of bound-state and quantum interference effects among different transition/ionization paths will be revealed. Combing new developed or developing ultrashort pulse technologies, we will further propose new schemes for probing and controlling ultrafast bound-state dynamical processes. The results of this project will benefit understanding deeply the fundamental physical processes in strong field physics, and lay foundation of atomic, molecular structures imaging and all-optical switching within attosecond time scale, etc.

阿秒脉冲及波长连续可调的自由电子激光等技术的不断发展使得束缚态超快动力学过程研究逐渐成为强场超快物理领域的热点研究方向。本项目瞄准这一前沿领域，拟开展基于束缚态的强场超快动力学过程机理及应用研究。建立和发展适用于描述包含系列束缚态的强场超快动力学过程，尤其是阿秒脉冲激发下包含传输效应的理论方法和数值计算程序。通过研究分析不同束缚态构成的初始状态在动量谱及高次谐波谱中表现出的新效应及其内在新规律，明确电子初始动量分布等细微因素对束缚态波包动力学及量子干涉效应的影响；探索包含时空耦合特性的阿秒瞬态光谱效应，揭示亚光学周期时间尺度内束缚态的超快非线性瞬态光学效应新规律以及不同跃迁及电离通道引起的量子干涉效应新机制；并结合国际上刚刚或正在发展的脉冲新技术，提出束缚态超快动力过程探测及控制新方案。项目成果对深入理解强场物理过程有重要意义，为实现原子、分子结构成像及阿秒时间尺度内的全光开关等奠定基础。

强场束缚态超快动力学过程研究逐渐成为超快物理阿秒科学领域的热点研究方向。本项目针对当前国际上超快电子动力学领域中亟待解决的部分关键科学问题，深入研究强场超快束缚态动力学的新效应、新机制，主要包括：创新性的发展了一套可以用于研究强场电子动力学过程的理论方法：普适的量子轨迹蒙特卡洛方法GQTMC，该方法在强场阿秒物理领域具有重要的应用前景；利用GQTMC方法定量再现了强场光电子全息实验结果，并明确给出库仑势和非绝热电离效应的贡献；发现激光光电子谱中全新的干涉结构并解释其亚周期动力学机制；发现了不同半周期光电子干涉在光电子动量谱中形成的圆环结构并解释其物理机制；利用新型的正交双色激光场，理论实验结合测定了Freeman共振时间延迟；建立和发展适用于描述周期性纳米结构中量子系统与超快激光脉冲共振强耦合相互作用的理论方法和数值计算程序，研究不同周期性纳米结构中量子系统与超短激光脉冲共振强相互作用时的新效应、新机理，等。..