RII Track-4: Experiments on a High Intensity, Coherent Plasma Laser through Stimulated Raman Backscattering

非技术描述激光器(受激辐射光放大)本质上是一种放大器，其运行依赖于将能量泵入称为激光介质的气体、液体或固体物质中的原子的电子中。超高功率(数十亿瓦)、超短(几十亿秒)激光脉冲的产生对激光介质提出了严格的要求。科学家们使用了优雅的光学技术和可以在极端强度下工作的等离子体(电离气体)来开发高功率脉冲激光。然而，进一步的进步需要了解放大介质中的过程，并克服限制输出功率的技术挑战。该项目致力于通过将特拉华州立大学的专业知识和仪器与劳伦斯利弗莫尔国家实验室(LLNL)的专业知识和仪器相结合，实现基于等离子体的超快激光输出功率的提高。国家科学基金会(NSF)设立的激励竞争研究计划(EPSCoR)的奖学金为首席研究员(PI)和她的学生提供了必要的支持，使他们能够从事涉及实验、理论和模拟的综合努力。该项目为早期职业研究人员和特拉华州立大学的学生提供了一个独特的机会，让他们在一家主要的国家设施中培训制造桌面高功率等离子激光器。特拉华州立大学是历史悠久的黑人学院和大学(HBCU)的成员。这项EPSCoR研究奖学金的目标是在桌面等离子体激光器中实现以拍瓦/埃瓦/泽塔瓦峰值功率的超短(20-30飞秒)脉冲。实验将使用受激拉曼背散射(SRBS)，其中种子激光脉冲功率的放大通过反向传播的泵浦和种子光束配置中的激发等离子体朗缪尔波发生。种子激光器将从特拉华州立大学运来，实验将在劳伦斯利弗莫尔国家实验室(LLNL)使用LLNL的木星激光设备(JLF)提供的泵浦激光器进行。该项目包括种子激光器的安装、等离子体波导的研制及其特性研究、JLF激光器泵浦的单级SRBS实验以及两级(两个气体射流)实验。这些实验将探索PI小组通过PIC模拟预测的饱和机制，并使用理论分析、模拟和实验研究相结合的综合努力来解决基于等离子体的高功率激光器的峰值功率饱和问题。该项目为PI和她的学生提供了一个独特的机会，将国内机构的仪器与大型国家设施中可用的仪器相结合，进行由理论和模拟指导的实验，并反过来提供有用的反馈来验证和帮助改进理论模型。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

Nontechnical DescriptionA laser (Light Amplification by Stimulated Emission of Radiation) is essentially an amplifier, whose operation depends on pumping energy into the electrons of atoms in a gas, liquid, or solid substance called the lasing medium. The production of very high-power (on the order of a few billion watts), ultra-short (a few billionth of a second) laser pulses places stringent demands on the lasing medium. Scientists have used elegant optical techniques and plasmas (ionized gas) that can operate at extreme intensities to develop high-power pulsed lasers. However, further advancement requires understanding processes within the amplifying medium and overcoming technological challenges that limit the output power. This project focuses on achieving increased output power of plasma based ultrafast lasers by combining the expertise and instrumentation available at Delaware State University with those of the Lawrence Livermore National Laboratory (LLNL). The fellowship grant from the National Science Foundation (NSF) Established Program to Stimulate Competitive Research (EPSCoR) provides the Principal Investigator (PI) and her students the support needed to pursue an integrated effort involving experiments, theory, and simulations. The project offers a unique opportunity for an early career researcher and students from Delaware State University, a member of the Historically Black Colleges and Universities (HBCU), to train at a premier national facility in building a table-top high-power plasma laser. Technical DescriptionThe goal of this EPSCoR Research Fellowship is to achieve ultrashort (20-30 femtosecond) pulses at petawatt/exawatt/zettawatt peak power in a table-top plasma-based laser. The experiments will use Stimulated Raman Backscattering (SRBS), in which amplification of a seed laser pulse power occurs via excited plasma Langmuir waves in a configuration of counter-propagating pump and seed beams. The seed laser will be shipped from Delaware State University and the experiments will be performed at the Lawrence Livermore National Laboratory (LLNL) using a pump laser available at LLNL's Jupiter Laser Facility (JLF). The project involves the installation of the seed laser, development of a plasma waveguide and studies of its characteristics, implementation of a single stage SRBS experiment pumped by a JLF laser, and finally a two stage (two gas jets) experiment. These experiments will explore the saturation mechanism predicted by the particle in cells (PIC) simulations by the PI's group and use an integrated effort that combines theoretical analysis, simulations, and experimental investigation to address the peak power saturation in plasma-based high-power lasers. The project provides a unique opportunity for the PI and her students to combine home institution's instrumentation with those available at large scale national facilities to conduct experiments that are guided by theory and simulation, and in turn provide useful feedback to validate and help improve theoretical models.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.