MRI: Acquisition of a High Intensity Tunable Femtosecond Laser.

MRI：获取高强度可调谐飞秒激光。

• 批准号: 1229674
• 负责人: Carlos Trallero
• 金额: $ 69.29万
• 依托单位: Kansas State University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2012
• 资助国家: 美国
• 起止时间: 2012-09-01 至 2016-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1229674&HistoricalAwards=false
• 关键词: MRI; Acquisition; Intensity; Tunable; Femtosecond

This NSF-MRI allows generating milli-Joule (mJ) level, few-cycle pulses (10 fs to 14 fs) in the mid-infrared (1400-2200 nm) spectral region that are carrier-envelope phase stable. To generate these pulses, a white-light seeded optical parametric amplifier (OPA) is pumped by a 20 mJ femtosecond laser. The pulses emerging from the OPA are then spectrally broadened and compressed. Such capabilities are at the forefront of current ultrafast physics and attosecond science, opening a window for new and exciting studies in the general area of laser-matter interaction.Extending these pulses to the mid-IR should enhance high-harmonic generation -- an effort presently pursued at just a handful of laboratories around the world. Driving the harmonics with these longer wavelengths will lead to a higher photon flux and energy. This high photon flux is critical for studies of non-linear UV/XUV phenomena as well as for extending our studies to the more complex systems of interest for most applications. The longer wavelength driving laser will also enable the investigation of electronic dynamics using a very different, rather unorthodox, approach. Namely, by taking advantage of the fact that dissociation in some molecules is an almost perfect analog of ionization in atoms, only few femtosecond laser pulses are required since nuclei move much slower than electrons. These pulses must, however, have long wavelengths to produce a measurable signal. In addition to the science advances, technological advances such as shaping attosecond pulses to eliminate their natural chirp or tailoring them to drive specific dynamics will be pursued. Such capabilities would be a substantial accomplishment and would, in turn, enable further scientific advances since scientific and technological breakthroughs go hand-in-hand in this field.Measuring the dynamics of and controlling electrons in matter are major themes that extend throughout much of atomic, molecular and optical (AMO) physics, chemistry, materials science, and even biology today. In fact, the first of the five "Grand Challenges for Basic Energy Science," as identified in the Department of Energy's special BESAC report in 2007, is "How do we control material processes at the level of electrons?" This theme appeared again in the National Research Council's "Physics 2010" report where the AMO contribution was entitled "Controlling the Quantum World." To accomplish these goals, laser pulses on the order of tens of attoseconds (1 as = 10^-18 s) are required. Such pulses are a challenge to produce, but by using high-harmonic generation (HHG), pulses below 100 as have been obtained in a few leading labs around the world, including here at the J. R. Macdonald Laboratory (JRML). This technological breakthrough has given birth to the field of attosecond science, which is presently one of the hottest in AMO physics. This project will employ these attosecond UV/XUV pulses to study atomic and molecular dynamics as well as to probe more complex condensed matter systems. In addition, by observing the HHG spectra and/or emitted electrons, structural changes in molecules can be observed as they happen, deepening our understanding of the underlying dynamics and thereby taking an important step in controlling chemical reactions at the quantum mechanical level.Beyond the technical and scientific impacts, this grant significantly impacts a large number of young scientists through hands-on training of the roughly seven postdocs, sixteen graduate students, and five undergraduate students hosted by the JRML. While the training opportunities mainly benefit graduate students and postdoctoral fellows, they also have an impact on undergraduate students through, for instance, the Physics Department's Research Experiences for Undergraduates (REU) program funded by the NSF. However, this laser source has also created a very broad collaboration between participants from institutions in three EPSCoR states who are currently funded primarily by NSF and DOE. The institutions involved are Kansas State University, Louisiana State University, Augustana College (an undergraduate institution in South Dakota), and the University of Kansas. The JRML group will leverage this new laser system to initiate additional collaborations following this model.

该NSF-MRI允许生成Milli-Joule（MJ）水平，在中红外（1400-2200 nm）光谱区域中，几乎没有周期脉冲（10 fs至14 fs），即载体 - Envelope相位稳定。为了生成这些脉冲，由20 MJ飞秒激光器泵送白色的播种光学参数放大器（OPA）。然后，从OPA出现的脉冲将在光谱上拓宽和压缩。这样的能力是当前超快物理和Attosend Science的最前沿，为在激光摩擦互动的一般领域开辟了一个新的令人兴奋的研究的窗口。将这些脉冲扩展到MID-IR应该增强高谐波一代 - 目前在世界各地的一些实验室中追求的努力。使用这些较长的波长驱动谐波会导致更高的光子通量和能量。这种高光子通量对于非线性UV/XUV现象的研究以及将我们的研究扩展到大多数应用的更复杂系统的研究至关重要。 较长的波长驱动激光器还将使用截然不同的，非正统的方法来研究电子动力学。 也就是说，通过利用这样一个事实，即某些分子中的分离是原子中电离的几乎完美的类似物，只有少量飞秒激光脉冲是需要的，因为核移动的移动速度比电子慢得多。 但是，这些脉冲必须具有长的波长才能产生可​​测量的信号。 除了科学的进步外，还将追求诸如塑造Attsond脉冲以消除其自然呼声或量身定制以推动特定动态的技术进步。 这样的能力将是一个实质性的成就，反过来，由于科学和技术突破在该领域中齐头并进，因此可以进一步的科学进步。要衡量物质中电子和控制电子的动力学是主要主题，这些主题延伸了整个原子，分子和光学（AMO）（AMO）物理学，化学，材料，材料科学和偶数生物学。实际上，在2007年能源部特别的BESAC报告中确定的五个“基本能源科学挑战”中的第一个是“我们如何控制电子水平的物质流程？”该主题再次出现在国家研究委员会的“ 2010年物理学”报告中，其中AMO的贡献标题为“控制量子世界”。为了实现这些目标，需要在数十秒（1 as = 10^-18 s）上按照激光脉冲。这种脉冲是生产的挑战，但是通过使用高谐波产生（HHG），在世界上一些领先的实验室中获得的脉冲（HHG）低于100，包括J. R. Macdonald Laboratory（JRML）。这一技术突破已经诞生了Attosecond Science领域，该领域目前是AMO物理学中最热门的科学之一。该项目将采用这些紫外线/XUV脉冲来研究原子和分子动力学，并探测更复杂的冷凝物质系统。 In addition, by observing the HHG spectra and/or emitted electrons, structural changes in molecules can be observed as they happen, deepening our understanding of the underlying dynamics and thereby taking an important step in controlling chemical reactions at the quantum mechanical level.Beyond the technical and scientific impacts, this grant significantly impacts a large number of young scientists through hands-on training of the roughly seven postdocs, sixteen graduate students, and five JRML主持的本科生。虽然培训机会主要使研究生和博士后研究员受益，但他们也通过NSF资助的本科生的研究经验（REU）计划对本科生产生了影响。但是，该激光源还建立了来自三个EPSCOR州的机构的参与者之间的广泛合作，这些国家目前主要由NSF和DOE资助。涉及的机构是堪萨斯州立大学，路易斯安那州立大学，奥古斯塔纳学院（南达科他州的本科机构）和堪萨斯大学。 JRML组将利用这种新的激光系统来启动此模型的其他协作。