The Ultimate Limit of Rescattering in Strong Laser Fields

强激光场中再散射的极限

• 批准号: 1607321
• 负责人: Barry Walker
• 金额: $ 32.05万
• 依托单位: University of Delaware
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2016
• 资助国家: 美国
• 起止时间: 2016-09-01 至 2022-02-28
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1607321&HistoricalAwards=false
• 关键词: Ultimate; Limit; Rescattering; Strong; Laser

When a material is in an intense laser, the laser removes electrons from the matter in a process known as ionization. A second step in the laser-matter interaction was discovered where, after the electron is removed in ionization, the laser accelerates the electron and forces it back to "re-collide" and excite the original material. These re-collisions are a primary way that lasers transfer energy and create new light and particles. Using laser re-collisions, the principal investigator has observed the emission of x-ray radiation, multiple additional electrons, and recently the shortest pulses of light ever achieved, which can measure reaction dynamics down to the level of an electron or nucleus. The impact of the laser re-collision mechanism now stretches far into the fields of atomic and molecular physics, physical chemistry, and plasma physics. Advances in laser technology, including science planned at 1,000 Trillion Watt High Intensity Laser Facilities worldwide, have pushed laser intensities to the limit where the recollision process breaks down. Broad questions addressed by the research that will promote the progress of science include "What is the ultimate limit for high energy radiation and particles emitted from laser interactions?" and, "With the breakdown of traditional laser-matter rescattering, can we learn to generate high energy radiation and particles efficiently using lasers?" This grant is co-funded by the Atomic, Molecular & Optical Physics program in the Physics Division and the Chemical Measurements and Imaging (CMI) program in the Chemistry division. The research will use high peak power lasers to understand the end of the rescattering mechanism as a function of the laser intensity, laser light color (wavelength), and material species being excited. The experiments are done in ultrahigh vacuum on individual atoms and molecules in a laser focus. The particles and radiation from the laser excited matter are analyzed with high resolution spectrometers specifically designed to handle the extreme energy of the products. The research involves intensive, hands-on training for graduate and undergraduate students in experiment and theory on applied and fundamental topics including: high intensity laser technology, optical system alignment and design, advanced computer programming, and data acquisition and processing. Students from the group have found significant positions across science and technology disciplines from national defense contracting to medical physics to laser material processing industry. The Principle Investigator will be chairing a conference to help students from the populous Mid-Atlantic region share research results. This section meeting is an excellent opportunity for the physics STEM students at the more than thirty universities and colleges within 100 miles of the conference site. The conference will be cohosted by the University of Delaware and Delaware State University (a historically black university).

当一种物质处于强激光中时，激光会将电子从物质中移除，这一过程被称为电离。激光与物质相互作用的第二步被发现，当电子在电离中被移除后，激光加速电子并迫使它“重新碰撞”并激发原始物质。这些再碰撞是激光传递能量并产生新光和粒子的主要方式。利用激光重碰撞，首席研究员已经观察到x射线辐射的发射，多个额外的电子，以及最近实现的最短光脉冲，这可以测量到电子或原子核水平的反应动力学。激光再碰撞机制的影响现在已经延伸到原子和分子物理、物理化学和等离子体物理等领域。激光技术的进步，包括计划在世界范围内建立1000万亿瓦高强度激光设施的科学，已经将激光强度推向了记忆过程崩溃的极限。这项研究解决了将促进科学进步的广泛问题，包括“激光相互作用发出的高能辐射和粒子的最终极限是什么？”以及“随着传统激光物质再散射的瓦解，我们能否学会利用激光有效地产生高能辐射和粒子？”该基金由物理部的原子、分子与光学物理项目和化学部的化学测量与成像（CMI）项目共同资助。该研究将使用高峰值功率激光器来了解作为激光强度，激光光色（波长）和被激发物质种类的函数的重散射机制的结束。实验是在超高真空中对激光聚焦的单个原子和分子进行的。激光激发物质的粒子和辐射用专门设计的高分辨率光谱仪进行分析，以处理产品的极端能量。该研究包括对研究生和本科生在应用和基础主题的实验和理论方面的强化，实践训练，包括：高强度激光技术，光学系统对准和设计，先进的计算机编程，以及数据采集和处理。该小组的学生在科学和技术学科中找到了重要的职位，从国防承包到医疗物理学到激光材料加工工业。首席研究员将主持一个会议，帮助来自人口稠密的中大西洋地区的学生分享研究成果。本次会议对于会议地点100英里内的30多所大学和学院的物理STEM学生来说是一个绝佳的机会。会议将由特拉华大学和特拉华州立大学（一所历史悠久的黑人大学）共同主办。