OP: Transforming Table-top Soft X-Ray Lasers into High Average Power Devices

将台式软x射线激光器转变为高平均功率器件基于等离子体放大器的小型和更易于使用的“桌面”软x射线激光器的最新进展使纳米级应用成为可能，包括超高空间分辨率显微镜，纳米结构的无缺陷打印，纳米簇和分子的电子结构和反应性研究，以及化学敏感纳米探针的开发，这些纳米探针将能够在三维空间中绘制纳米级物体的组成。虽然这些激光器具有体积紧凑的优点，但它们在许多应用中的使用仍然受到其低平均功率的限制。该研究旨在将台式软x射线激光器推进到高平均功率器件，目标是最终从紧凑的器件中获得60-100 eV光子能量区域的多毫瓦平均功率激光束，这将极大地影响几个领域的应用。我们计划利用前所未有的控制水平来定制等离子体放大器，以实现更高的效率，同时通过使用新型二极管泵浦高能超短脉冲激光驱动器提高重复率，从而显著提高平均功率。技术：在目前最先进的软x射线碰撞激光器中，只有百分之几的激光泵能量沉积在增益区域。最近的实验和模拟表明，相对较小的泵浦能量时间分布变化可以导致软x射线激光效率的大幅提高。我们建议利用这种未开发的高灵敏度，通过高水平的控制来调整泵浦能量沉积速率，从而产生具有更大增益和更少折射损失的等离子体，从而显着提高效率和输出功率。将进行广泛的流体力学/原子物理模拟和实验，涵盖广泛的泵参数范围，以确定最大限度地提高软x射线激光输出能量的泵脉冲序列。由此产生的软x射线激光效率的提高将与一种新型高能二极管泵浦固体激光驱动器可能实现的重复率的增加相结合。这可能导致桌面软x射线激光束在60-100 eV光子能量区域的平均输出功率比目前可用的紧凑相干光源高几个数量级。更有效的泵浦也将促进实用软x射线激光器的扩展到更短的波长。紧凑的软x射线激光器向高平均功率器件的转变有望在纳米级成像、材料的无缺陷图像化和材料表征方面产生广泛的技术影响。该项目将为研究生提供令人兴奋的多学科论文项目，并有机会在先进激光系统的工程和物理方面工作。拟议的项目还将有助于培养一个具有重大工业利益和经济影响的领域的多样化劳动力，因为半导体行业正在接近使用极紫外光刻技术大规模生产计算机处理器的开始。我们计划利用拟议项目提供的机会，让本科生、高中生和高中教师等不同群体参与研究。我们计划在暑假期间让高中生参与这个项目。

Transforming Table-top Soft X-Ray Lasers into High Average Power DevicesAbstractNon-Technical: Recent advances in compact and more readily accessible "table-top" soft x-ray lasers based on plasma amplifiers are enabling nano-scale applications including ultra-high spatial resolution microscopy, the defect-free printing of nanostructures, the study of the electronic structure and reactivity of nano-clusters and molecules, and the development of chemically sensitive nano-probes that will be able to map the composition of nano-scale objects in 3-dimensions. While these lasers have the advantage of their compact size, their use in many applications is still limited by their low average power.The proposed research is designed to advance table-top soft x-ray lasers into high average power devices , with the goal of ultimately achieving multi-milliwatt average power laser beams in the 60-100 eV photon energy region from a compact device, greatly impacting applications in several fields. We plan to achieve a significant increase in average powers by tailoring the plasma amplifier with an unprecedented level of control to achieve higher efficiency while simultaneously increasing the repetition rate by using a new type of diode-pumped high energy ultra-short pulse laser driver.Technical: In the present state-of-the-art collisional soft x-ray lasers only several percent of the laser pump energy is deposited in the gain region. Recent experiments and simulations show that relatively minor alterations in the pump energy temporal distribution can result in a large increase in the soft x-ray laser efficiency. We propose to take advantage of this unexploited high sensitivity to significantly increase the efficiency and output power by tailoring the pump energy deposition rate with a high level of control to create a plasma with larger gain and reduced refraction loses. Extensive sets of hydrodynamic/atomic physics simulations and experiments covering a broad range of pump parameters will be conducted to identify the pump pulse sequence that maximizes the soft x-ray laser output energy. The resulting increase in the soft x-ray laser efficiency will be combined with an increase in repetition rate made possible by a novel high energy diode-pumped solid state laser driver. This could result in table-top soft x-ray laser beams with orders of magnitude higher average output powers in the 60-100 eV photon energy region than presently available compact coherent sources. The more efficient pumping will also facilitate the extension of practical soft x-ray lasers to shorter wavelengths.The transformation of compact soft x-ray lasers into high average power devices can be expected have a broad technology impact in nanoscale imaging, defect-free patterning of materials, and materials characterization. The propose research will provide exciting multi-disciplinary thesis projects for graduate students, with the opportunity of working in both the engineering and the physics of advanced laser systems. The proposed project will also contribute to train a diverse workforce of an area of great industrial interest and economic impact, as the semiconductor industry is approaching the start of the mass production of computer processors using extreme ultraviolet lithography. We plan to use the opportunities offered by the proposed project to involve a diverse group of undergraduates, high school students, and high school teachers in research. We plan to include the participation of high school students in the project during the summers.