MRI: Development of Angle-Resolved Light Scattering System for Ultrafast Surface Spectroscopy

该奖项来自主要研究仪器项目和EPSCoR项目，支持开发最先进的时间和角度分辨半球形弹性光散射（TARHELS）仪器，用于在低温下以飞秒分辨率观察光散射。该设备将是这种类型的第一个光学系统，并提供超越当前限制的独特功能，并将在凝聚态研究的前沿领域推进最先进的仪器标准。多用户使用该仪器将大大增加和推进波多黎各-马亚圭斯大学物理系的研究活动。除了科学影响之外，该项目还为波多黎各大学（University of Puerto Rico）的研究生提供了良好的教育和培训机会。波多黎各大学是一所高等教育机构，为美国最多的西班牙裔STEM学生提供服务和毕业生。学生将接受广泛的培训，使用国家实验室和美国工业中经常使用的现代超快衍射技术。该TARHELS仪器将为凝聚态物质的超快泵浦探针表面光谱提供独特的可能性，同时使用大规模非球面反射光学技术实现飞秒分辨率的半球形散射指标的高质量记录和光谱分析。该装置被设计成一个计算机控制的装置，与外部超快激光脉冲源一起工作。使用几种几何形状将能够监测均匀波和表面波的光散射。该项目还将开发用于快速分析散射场的用户界面和算法。收集半球上的时间和角度分辨散射，TARHELS仪器将提供瞬态自相关函数和表面功率谱密度的实时重建和可视化，从而能够深入了解多尺度结构不规则性的非稳态。在低温下运行，TARHELS系统将产生大量关于中尺度随机表面的非平衡无序，有关晶粒尺寸依赖的电子-晶格相互作用，物质非平衡量子相中的电子相关作用以及多尺度量子凝聚态动力学的新信息，包括不同功能材料中绝缘体到金属的相变，相关氧化物，强激光激励下的拓扑绝缘体和超导体。

This award from the Major Research Instrumentation program and the EPSCoR program supports the development of a state-of-the-art time- and angle-resolved hemispherical elastic light scattering (TARHELS) instrument to observe light scattering with femtosecond resolution at cryogenic temperatures. The apparatus will be the first optical system of this kind, and provides unique capabilities beyond current limitations and will advance the standards for state-of-the-art instrumentation in a field at the forefront of condensed matter research. Multi-user access to the instrument will significantly increase and advance the research activity of the Physics Department at the University of Puerto Rico-Mayaguez. Beyond its scientific impact, the project provides an excellent education and training opportunity for graduate students at the University of Puerto Rico, a higher education institution that serves and graduates the largest number of Hispanic STEM students in the United States. Students will receive extensive training in working with the modern ultrafast diffraction techniques that are frequently utilized in National Labs and the US industry.This TARHELS instrument will provide unique possibilities for the ultrafast pump-probe surface spectroscopy of condensed matter, while enabling high-quality recording and spectral analysis of hemispherical scattering indicatrix with femtosecond resolution using large-scale aspherical reflective optics. The setup is designed as a computer-controlled apparatus that operates with external ultrafast laser pulse sources. The use of several geometries will enable monitoring of the light scattering of homogenous and surface waves. The project will also develop the user interface and algorithms for fast analysis of the scattering field. Collecting the time- and angle-resolved scattering over a hemisphere, the TARHELS instrument will provide the real-time reconstruction and visualization of transient autocorrelation function and power spectral density of the surface, enabling insight into the nonsteady state of multi-scale structural irregularities. Operating at low temperatures, the TARHELS system will yield substantially new information about nonequilibrium disorder of stochastic surfaces on the mesoscale, information about grain-size-dependent electron-lattice interactions, the role of electronic correlations in nonequilibrium quantum phases of matter, and multi-scale quantum condensed matter dynamics, including insulator-to-metal phase transition in different functional materials, correlated oxides, topological insulators and superconductors under strong laser excitation.