Terahertz Recollisions

太赫兹再碰撞

基本信息

批准号：
1710639
负责人：
Mark Sherwin
金额：
$ 55万
依托单位：
University of California-Santa Barbara
依托单位国家：
美国
项目类别：
Continuing Grant
财政年份：
2017
资助国家：
美国
起止时间：
2017-08-01 至 2020-07-31
项目状态：
已结题

来源：
https://www.nsf.gov/awardsearch/showAward?AWD_ID=1710639&HistoricalAwards=false
关键词：
Terahertz Recollisions

项目摘要

Nontechnical AbstractHigh-energy physicists explore the structure of matter by colliding elementary particles like protons and electrons. In solids, currents--like those generated in a photovoltaic cell after illumination by sunlight--are usually carried by entities called "quasi-particles." When acted on by a force, quasi-particles behave like particles, but actually involve the co-ordinated motions of thousands to millions of atoms. If an atom in a solid were scaled up to be the size of a person, then a quasi-particle would look something like "the wave" in a large, full stadium. The PI's group has recently discovered a method to accelerate and collide quasi-particles about 1 trillion times per second (1 Terahertz). The experimental signature of quasi-particle collisions is a rainbow-like spectrum of light that contains dozens of frequencies, or sidebands, that are equally spaced like the teeth on a comb. Each sideband, carries information about the speed with which the quasiparticles have collided, and the quantum-mechanical properties of the solid through which they have been accelerated before colliding. In this project, the PI's group will carefully analyze both the intensities and polarizations of the sidebands from a variety of electronic materials in order to elucidate the laws that govern the motion of quasiparticles and to search for new phases of strongly-driven matter. Possible applications of the proposed research include faster and more energy efficient optical communications and internet, improved optical clocks that are necessary in the global positioning system, and the ability to rapidly and reversibly tune the properties of materials. This project will support the training of two Ph. D. students and several undergraduates, who will learn a variety of skills that are critical to preserving U. S. competitiveness in the high-technology sector.Technical AbstractThis project addresses one of the grand challenges of 21st century science--how does quantum matter behave when it is driven very far from thermal equilibrium. The goals of this project are to take advantage of new opportunities in the study of strongly-driven matter to (1) develop a method of measuring the Berry curvature of bands in solids, which is critical to understanding the dynamics of quasiparticles; (2) elucidate the nature of quasiparticles in materials in which correlations between electrons are strong, like the parent compounds of high-Tc superconductors; and (3) search for new quantum-mechanical phases near the edges of materials that are driven by strong, time-periodic fields. In order to reach these goals, this project will use the recent discovery of high-order sideband generation (HSG) by the PI's group. Each of the materials of interest will be illuminated by a NIR laser while it is being driven by a strong THz-frequency electric field, and the intensities and polarizations of the resulting HSG spectra will be analyzed. Experiments will be closely coupled with theory to reach the project goals.

非技术性抽象thigh-Emgy物理学家通过碰撞质子和电子等基本颗粒来探索物质的结构。在固体中，像阳光照明后在光伏电池中产生的水流一样 - 通常由称为“准粒子”的实体携带。当用力扮演时，准粒子的行为就像颗粒一样，但实际上涉及数千至数百万原子的协同运动。如果将固体中的原子缩放到一个人的大小，那么准粒子看起来像是大型全体育场中的“波浪”。 PI的组最近发现了一种加速和碰撞准粒子的方法，每秒约1万亿次（1 Terahertz）。准粒子碰撞的实验特征是彩虹状光谱，其中包含数十个频率或边带，它们像梳子上的牙齿一样间隔。每个侧带，都传递有关准粒子碰撞的速度的信息，以及在碰撞之前加速其固体的量子力学特性。在该项目中，PI小组将仔细分析边带的强度和极化，从各种电子材料中，以阐明控制准粒子运动的法律，并寻找强烈驱动物质的新阶段。拟议研究的可能应用包括更快，更节能的光学通信和互联网，改进的全球定位系统中必需的光学时钟以及快速，可逆地调整材料的性能的能力。该项目将支持对两名D. D.学生和几名大学生进行培训，他们将学习各种技能，这些技能对于保持美国的高科技领域的竞争力至关重要。技术摘要该项目是21世纪科学的巨大挑战之一 - 当量子与热均衡非常遥远时，量子问题确实是量子。该项目的目标是利用强烈驱动物质的新机会，以（1）开发一种测量固体中带的浆果曲率的方法，这对于理解准片粒的动态至关重要；（2）在电子之间相关性很强的材料中阐明了准颗粒的性质，例如高-TC超导体的母体化合物；（3）在材料边缘附近搜索由强，时间周期性场驱动的材料边缘附近的新量子机械阶段。为了实现这些目标，该项目将使用PI小组最近发现高阶侧带（HSG）。每种感兴趣的材料都会被NIR激光器照亮，同时它是由强大的THZ频率电场驱动的，并且将分析所得的HSG光谱的强度和极化。实验将与理论紧密结合以实现项目目标。