Intense Laser-Atom Physics in Scaled Interactions

该项目对单原子在新的相互作用条件下的响应进行了全面的研究，这不仅将为标度定律和理论提供基本的检验，而且将开启强场物理中一些独特的实验研究。该项目的总体目标是通过在光子能量远远小于原子结合能的区域利用强场相互作用的波长标度来扩大实验研究的范围。强场相互作用的各个方面都具有隐含的波长依赖性，这是一个关键的标度参数，还没有以系统的方式被探索或利用。用几个周期的中红外(2微米和4微米波长)脉冲进行新颖的电离实验来解决这些标度律是至关重要的，因为它测试了我们对强激光-原子相互作用的所有理解的基础。利用这些原理，将能够进行一些关键的研究，包括显著增加能够经历强激光场的原子系统的数量，允许对单电子和双电子系统进行系统研究，以及检验预备态的强场相互作用并启动对标度定律的全球研究。孤立原子与强电磁场的相互作用是原子、分子和光学物理中的前沿问题之一的基础。通过吸收多个光子将大量能量耦合到一个原子中的能力提出了许多有趣的问题，并导致了许多新的发现，如高于阈值的电离、高次谐波产生、多次电离和绝热稳定。问题的核心是原子对激光脉冲的非微扰响应，这种脉冲施加的外场可与将电子绑定到原子核的力相媲美。对这个基本的原子物理问题的持续兴趣源于它在其他物理和技术领域的广泛影响。单原子响应是等离子体中发现的更复杂现象、惯性约束聚变概念、先进粒子加速和天体物理学的初始条件。强烈的激光-原子相互作用本身正在为短波长科学、量子控制和推进超快电子物理中的一门新兴学科--阿特物理学--带来新的机遇。最近，用于产生用于这些研究的超快激光脉冲的光学技术已经达到了可以完全确定电磁场的复杂程度，即绝对相位和幅度。此外，这项研究的跨学科性质与最先进的超快光学技术相结合，为本科生和研究生提供了极好的培训基础。

This project undertakes a comprehensive study of the single atom response under novel interaction conditions that will not only provide basic tests of scaling laws and theory but also initiate some unique experimental investigations in strong field physics. The overall objective of the project is to broaden the scope of experimental investigations by utilizing the wavelength scaling of the strong field interaction in the regime where the photon energy is much smaller than the atomic binding energy. Various aspects of the strong-field interaction have an implicit wavelength-dependence that is a crucial scaling parameter and has not been explored or exploited in a systematic fashion. Addressing these scaling laws with novel ionization experiments using few-cycle mid-infrared (2 micron and 4 micron wavelength) pulses is crucial since it tests the very foundations of all our understanding of the intense laser-atom interaction. Using these principles a number of key studies will be enabled and include significantly increasing the number of atomic systems capable of experiencing intense laser fields, allowing systematic studies of one- and two-electron systems, and examining strong field interactions for prepared states and initiate a global investigation of scaling laws.The interaction of an isolated atom with an intense electromagnetic field is the basis for one of the forefront problems in atomic, molecular and optical physics. The ability to couple large amounts of energy into an atom by the absorption of many photons posed many intriguing questions and has led to many new discoveries such as above-threshold ionization, high-harmonic generation, multiple ionization and adiabatic stabilization. At the core of the problem is the non-perturbative response of the atom to a laser pulse that imposes an external field comparable to the forces binding the electrons to the nucleus. The continuing interest in this fundamental atomic physics problem is derived from its broad implications in other areas of physics and technology. The single atom response is the initial condition of more complex phenomena found in plasmas, inertial confined fusion concepts, advance particle acceleration and astrophysics. The intense laser-atom interaction itself is opening new opportunities in short wavelength science, quantum control and advancing an emerging discipline in hyperfast electron physics, attophysics. Recently, the optical techniques used for producing the ultra-fast laser pulses for these studies have reached a level of sophistication where the electromagnetic field can be completely determined, i.e. absolute phase and amplitude. Furthermore, the interdisciplinary nature of this research coupled with state-of-the-art ultra-fast optical technology provide an excellent training ground for both undergraduate and graduate students.