Intense laser-Atom Physics in Scaled Interactions

1960年激光的发明推动了一系列科技进步，从通信到外科手术，从面部识别到火星土壤分析。这些创新的核心是激光与实物的相互作用，例如超市里的条形码阅读器。这个项目将研究激光与所有物质的基本组成部分原子的特定相互作用。在这种相互作用中，来自激光的大量能量耦合到原子中，并通过将原子分裂成次级粒子（如电子、离子和其他光子）而耗散。分析碎裂过程的组成和成分之间的能量流动，提供了一个微观的基本物理视图。在该项目中，使用灵敏的探测器配置来测量粒子的类型，它们的能量含量和它们在空间中的发射方向。该程序实现了利用经典和量子力学模型预测的尺度的详细策略，用于探索单原子对强激光场响应的全局物理。关键的缩放参数是激光的颜色，即波长，而PI显示了新型波长激光如何将实验的广度扩展到一个未探索的领域，从而有助于我们对自然的整体理解。了解这一基本的物理原理可以在为社会提供直接利益的应用中加以利用，例如非侵入性手术和未来的能源。此外，该研究小组开发的激光源有望在其他科学技术领域得到广泛应用。此外，本研究的跨学科性质与最先进的光学工程相结合，为博士后、本科生和研究生提供了极好的培训场所。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技术领域做出贡献。更具体地说，原子和分子暴露在强烈的（原子单位场），飞秒光脉冲，其波长可以在0.4-4微米之间变化。在这些低频率下，电子响应，例如电离，是高度非线性的，使电子振动的场能可以超过价电子的结合能。在实验中，电离电子被角能量分解，并作为激光强度、极化和频率的函数进行了研究。主要目标是绘制强场电离的全局行为，观察它如何随着尺度场参数的变化而演变，提供严格的理论测试，并确定物理中的不变行为。此外，该计划将研究扩展到高频区域，即x射线。这是通过使用SLAC国家实验室的x射线自由电子激光器（XFEL）完成的。XFEL可以产生与我们实验室激光器相当的软x射线场。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

The invention of the laser in 1960 enabled a wide range of scientific and technological advances, from communications to surgery to facial recognition to analysis of Martian soil. At the heart of these innovations is the interaction of the laser light with physical objects, for example the bar code reader at the supermarket. This project will study a specific interaction of laser light with the basic building block of all matter, the atom. In this interaction, a large amount of energy from the laser light is coupled into the atom and dissipated by fragmenting the atom into secondary particles such as electrons, ions and other photons. Analyzing the composition of the fragmentation process and the energy flow among the constituents provides a microscopic view of the elementary physics. In the project, sensitive detector configurations are used to allow the measurement of the type of particle, their energy content and their emission direction in space. The program implements a detailed strategy of exploiting the scaling predicted by both classical and quantum mechanical models for exploring the global physics of the single atom response to an intense laser field. The critical scaling parameter is the color, i.e. wavelength, of the laser light and the PI shows how novel wavelength lasers can extend the breadth of experiments into an unexplored regime and thus contribute to our overall understanding of nature. Understanding this basic physics can be exploited in applications that provide direct benefits to society, such as non-invasive surgery and tomorrow’s energy sources. In addition, the laser sources developed by the research team are anticipated to have broad applications in other sectors of science and technology. Furthermore, the interdisciplinary nature of this research coupled with state-of-the-art optical engineering provide an excellent training ground for postdocs, 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. 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 microns. 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 angularly energy resolved 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 program extends the studies into the high frequency regime, i.e. x-rays. This is accomplished by using the X-ray Free Electron Laser (XFEL) at SLAC National Laboratory. The XFEL can generate fields in the soft x-ray regime comparable to our laboratory lasers.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.