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

这项来自重大研究仪器计划和EPSCoR计划的奖项支持开发最先进的时间和角度分辨半球弹性光散射(TARHELS)仪器，以观测低温下飞秒分辨率的光散射。该装置将是这种类型的第一个光学系统，并提供超越目前限制的独特能力，并将推动凝聚态研究前沿领域的最先进仪器的标准。多用户使用该仪器将大大增加和推进波多黎各大学马亚圭斯大学物理系的研究活动。除了其科学影响，该项目还为波多黎各大学的研究生提供了一个极好的教育和培训机会。波多黎各大学是一所高等教育机构，为美国最多的拉美裔STEM学生提供服务并毕业。学生将接受广泛的培训，使用国家实验室和美国工业经常使用的现代超快衍射技术。这台TARHELS仪器将为凝聚态物质的超快泵浦-探测表面光谱提供独特的可能性，同时能够使用大规模非球面反射光学系统以飞秒分辨率高质量地记录和光谱分析飞秒分辨率的半球散射指示器。该装置被设计为计算机控制的设备，与外部超快激光脉冲源一起运行。几种几何结构的使用将使监测均匀波和表面波的光散射成为可能。该项目还将开发用于快速分析散射场的用户界面和算法。收集半球上时间和角度分辨的散射，TARHELS仪器将提供瞬时自相关函数和表面功率谱密度的实时重建和可视化，使人们能够洞察多尺度结构不规则的非稳态。在低温下运行的TARHELS系统将产生大量新的信息，包括介观尺度上随机表面的非平衡无序，与颗粒尺寸相关的电子-晶格相互作用的信息，电子关联在物质非平衡量子相中的作用，以及多尺度量子凝聚物质动力学，包括不同功能材料、相关氧化物、拓扑绝缘体和超导体在强激光激励下的绝缘体到金属相变。

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.