MRI: Acquisition of a High-Power 2-um Laser System as the Backbone of an Utrafast X-Ray/THz Facility

该项目，获得一个高峰值功率高重复率超快红外激光系统在2微米波长，提供了一个多用户设施的骨干，名为“用户设施阿秒软x射线和太赫兹（UFAST）"。该激光系统拥有当今世界同类产品中最高的平均功率，（十亿分之一秒的十亿分之一）软X射线光子源，其具有足够的光子能量，用于在最深层次直接激发基本原子，例如碳、氮和氧，并且还能够实现高场和少的单周期脉冲持续时间的长波长红外和太赫兹源。这些光子源和泵浦激光器将用于开展前沿研究项目，其中设施用户开发世界上最快的x射线光子源，以原子空间分辨率跟踪自然时间尺度上的电子运动，监测量子/拓扑相变动力学，研究材料中新的光诱导物理和化学过程，测试新型冷纳米等离子体源的新理论，并进一步改进用于探测宇宙未知区域的太赫兹光谱工具。这些研究项目的成果将推进物理、化学和行星科学以及光学工程方面的知识和技术。UFAST提供了世界上没有的独特参数，将提高美国在高通量超快技术和阿秒科学方面的竞争力。UFAST的工程和研究活动将为研究生和本科生以及博士后学者提供前沿超快研究和技术的机会，特别是促进少数民族学生在尖端研究项目中的培训。未来一代的劳动力将接受涉及先进光子源和探测器的独特设施的建设和操作方面的培训，并将获得研究、团队合作和领导技能。除了其应用的多学科性质外，该设施还将面向美国和世界各地的用户，并将促进跨研究领域和机构以及实验学家和理论家之间的合作。即将获得的激光系统将提供2 μ m波长和几个周期持续时间的脉冲，其载波包络相位（CEP）稳定在100 kHz的重复频率。它将用于泵浦极紫外和水窗（284 - 543 eV）范围内的孤立阿秒脉冲的台式光子源，以及泵浦长波红外（8 - 15 μ m）和太赫兹（0.6 - 60 THz）范围内的几个单周期脉冲的光子源。这种新的能力将使研究能够在若干领域取得进展：对气体和凝聚相目标、量子和拓扑系统以及表面上由电子动力学驱动或涉及电子动力学的过程进行时间分辨研究，如电子相关、电荷迁移和转移;研究固体中各种激光参数下的强场现象，特别是要求强度的准静态状态;研究新的光学击穿机制和优化激光加工质量;实验演示光子诱导低温非平衡纳米等离子体;用太赫兹时间扩展实验室光谱库-领域光谱学，以填补有关太阳系的组成和演变的知识空白。这个奖项反映了NSF的法定使命，并已被认为是值得支持，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。

This project, Acquiring a High-peak-power High-repetition-rate Ultrafast Infrared Laser System at 2 µm Wavelength, provides the backbone of a multi-user facility named, "User Facility for Attosecond Soft x-rays and Terahertz (UFAST)". With the highest average power of its kind anywhere in the world today, this laser system will enable a tabletop attosecond (a billionth of a billionth of a second) soft-x-ray photon source at record high flux with sufficient photon energies for directly exciting, at the deepest level, essential atoms, such as carbon, nitrogen, and oxygen, and also enable long-wavelength-infrared and terahertz sources of high-field and few – single cycle pulse duration. These photon sources and the pump laser will be utilized to carry out frontier research projects where facility users develop the world’s fastest x-ray photon source, track electron motion at its natural time scale with atomic spatial resolution, monitor quantum/topological phase transition dynamics, investigate new photo-induced physical and chemical processes in materials, test a new theory for a novel cold-nanoplasma source, and further improve a terahertz spectroscopic tool for probing uncharted regions of the universe. Results of these research projects will advance knowledge and technologies in physical, chemical, and planetary sciences, as well as optical engineering. UFAST delivers unique parameters that are not available around the world and will enhance US competitiveness in high-flux ultrafast technologies and attosecond science. The engineering and research activities at UFAST will grant graduate and undergraduate students, as well as postdoctoral scholars, access to frontier ultrafast research and technologies, and particularly promote training of minority students in cutting-edge research projects. The future generation of work force will be trained in the construction and operation of a unique facility involving advanced photon sources and detectors, and will obtain research, teamwork, and leadership skills. In addition to the multidisciplinary nature of its applications, the facility will be accessible to users across the US and from around the world and will stimulate collaborations across research fields and institutions, as well as between experimentalists and theorists.The laser system to be acquired will deliver 2-µm-wavelength and few-cycle-duration pulses with carrier envelope phase (CEP) stabilization at a repetition rate of 100 kHz. It will be used to pump a table-top photon source of isolated attosecond pulses in the extreme ultraviolet (XUV) and water window (284 – 543 eV) range, and to pump photon sources of few – single-cycle pulses in the long wavelength infrared (8 – 15 m) and terahertz (0.6 – 60 THz) range. This new capability will enable research advances in several areas: time-resolved investigation of processes driven by or involving electronic dynamics, such as electron correlation, charge migration and transfer, in gas and condensed phase targets, quantum and topological systems as well as at surfaces; investigation of strong-field phenomena, particularly the intensity-demanding quasistatic regime, in solids over a variety of laser parameters; investigation of new optical breakdown mechanisms and optimization of laser machining quality; experimentally demonstrating photon-induced low-temperature non-equilibrium nanoplasmas; and extending laboratory spectral library with terahertz time-domain spectroscopy to fill a knowledge gap regarding the composition and evolution of the solar system.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.