Intense Laser-Atom Physics in Scaled Interactions

激光与物质的基本相互作用为现代基础和应用光学研究提供了基础。最近探测到的黑洞碰撞发出的引力波证实了爱因斯坦的引力理论，这对基础研究的影响就是例证。这一成就的核心是光学干涉仪探测器。一般来说，干涉仪在探测微小干扰方面具有极高的灵敏度，无论是在空间中传播的引力波，还是本项目中探索的原子中电子的微小运动。光和物质的相互作用也被利用在为社会提供更多有形利益的应用中，例如非侵入性手术和未来的能源。在这些情况下，以精确和可控的方式将大量激光能量引导到物质中的能力是至关重要的。了解精确塑造激光与物质相互作用的物理原理是这个项目的主要目的。当大量激光耦合到物质中时，能量通过碎裂物质而消散，释放出电子、离子和光子等次级粒子。分析碎裂过程的组成和组分之间的能量流动提供了基本物理的微观视角。在这个项目中，灵敏的探测器配置被用来测量粒子的类型、它们的能量含量和它们的发射方向，同时考虑到干扰。该程序实现了一种详细的策略，利用半经典和量子模型预测的比例来探索单个原子对强烈电磁场的响应的全局物理。关键的定标参数是激光的颜色，即频率，该项目概述了新的波长激光如何将实验的广度扩展到未知的区域，从而有助于我们对自然的全面理解。更具体地说，原子和分子暴露在强(原子单位的场)飞秒光脉冲中，其波长可以从0.4-4和956；米变化。在这些低频率下，电子响应，如电离，是高度非线性的，使电子抖动的场能可能超过价电子的结合能。在实验中，对电离电子的角度和能量进行了分解，并研究了它与激光强度、极化和频率的函数关系。主要目标是绘制强场电离的全球行为图，观察它如何随场参数的变化而演变，提供严格的理论测试，并确定物理学中的不变行为。此外，该项目研制的激光光源在科学技术方面具有广泛的应用前景。这项研究的跨学科性质与最先进的光学工程相结合，为本科生和研究生提供了一个极好的培训基础。前小组成员正在为学术界、能源和国防实验室以及私营部门的各个科学和技术领域做出贡献。

The fundamental interaction of laser light with matter provides the foundation of modern basic and applied optical research. The impact on basic research was exemplified by the recent detection of gravitational waves emitted by colliding black holes, which confirmed Einstein's theory of gravity. At the heart of this achievement is an optical interferometer detector. In general, interferometers have exquisite sensitivity for detecting small disturbances, be they gravitational waves propagating through space or the minute motion of an electron in an atom as explored in this project. The interaction of light and matter is also being exploited in applications that provide more tangible benefits to society, such as non-invasive surgery and future sources of energy. In these cases, the ability to direct large amounts of laser energy into matter in a precise and controllable manner is paramount. Understanding the physics responsible for precisely sculpting the laser-matter interaction is a major thrust of this project. When a large amount of laser light is coupled into matter, the energy is dissipated by fragmenting the matter, releasing secondary particles such as electrons, ions, and photons. Analyzing the composition of the fragmentation process and the energy flow among the constituents provides a microscopic view of the elementary physics. In this project, sensitive detector configurations are used to allow the measurement of the type of particles, their energy content, and their emission direction, taking into account interference. This program implements a detailed strategy of utilizing the scaling predicted by semi-classical and quantum models for exploring the global physics of a single atom response to an intense electromagnetic field. The critical scaling parameter is the color, i.e. frequency, of the laser light and the project outlines how novel wavelength lasers can extend the breadth of experiments into an unexplored regime and thus contribute to our overall understanding of nature. More specifically, atoms and molecules are exposed to intense (atomic unit of field), femtosecond light pulses whose wavelength can be varied from 0.4-4 μm. At these low frequencies, the electronic response, e.g. ionization, is highly nonlinear and the field energy that quivers the electron can exceed the binding energy of the valence electron. In the experiment, the ionized electrons are resolved in angle and energy, and studied as a function of laser intensity, polarization and frequency. The main objectives are to map the global behavior of strong-field ionization, observe how it evolves with scaled field parameters, provide stringent tests of theory and identify the invariant behavior in the physics. In addition, the laser sources developed by this program have broad applications in science and technology. The interdisciplinary nature of this research coupled with state-of-the-art optical engineering provide an excellent training ground for both undergraduate and graduate students. Former group members are contributing to various areas of science and technology in academia, energy and defense laboratories, and the private sector.