Multiple-Pulse, Single-Shot Femtosecond Spectroscopy of Condensed Phases

凝聚相的多脉冲、单次飞秒光谱

• 批准号: 9404548
• 负责人: Keith Nelson
• 金额: $ 46.03万
• 依托单位: Massachusetts Institute of Technology
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 1994
• 资助国家: 美国
• 起止时间: 1994-06-01 至 1998-05-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9404548&HistoricalAwards=false
• 关键词: Multiple; Pulse; Single; Shot; Femtosecond

In this project in the Physical Chemistry Program of the Chemistry Division, Prof. Keith A. Nelson of the Massachusetts Institute of Technology will engage in a series of continuing investigations in the field of optical control of molecular and material behavior, including structural and chemical rearrangements in condensed media. These studies rely on the use of multiple-pulse femtosecond spectroscopy at visible, near-infrared or near-ultraviolet wavelengths. Shaped femtosecond pulse sequences are to be used to drive large-amplitude vibrations in crystal lattices to enable the spectroscopic observation of far-from-equilibrium crystal geometries. Additional work will concentrate on the development of an automated time-domain vibrational spectrometer, the manipulation of electronic coherences to observe coherent wavepacket dynamics in electronic levels accessible only through two-photon transitions, and other topics. The initial stages of the research will be devoted to the implementation of improved methods for the generation, characterization, and amplification of complex femtosecond waveforms. Current forefront research in physical chemistry includes the study of molecular processes at ultra-short time scales that correspond to the period of one molecular vibration ( a few femtoseconds). These investigations have the potential of providing methods for the control of molecular reactions and other dynamical processes, as well as providing optical analogs of the nuclear magnetic resonance technique to study condensed phase optical spectroscopy.

在化学学部物理化学计划的这个项目中，麻省理工学院的Keith a. Nelson教授将参与一系列关于分子和材料行为的光学控制领域的持续研究，包括凝聚态介质中的结构和化学重排。这些研究依赖于在可见光、近红外或近紫外波段使用多脉冲飞秒光谱。形状的飞秒脉冲序列将用于驱动晶格中的大振幅振动，从而使远离平衡的晶体几何形状的光谱观察成为可能。额外的工作将集中在自动时域振动光谱仪的开发，电子相干的操作，以观察只能通过双光子跃迁获得的电子能级中的相干波包动力学，以及其他主题。研究的初始阶段将致力于实现复杂飞秒波形的生成、表征和放大的改进方法。当前物理化学的前沿研究包括在超短时间尺度上对分子过程的研究，该时间尺度对应于一个分子振动的周期（几飞秒）。这些研究有可能为分子反应和其他动力学过程的控制提供方法，并为研究凝聚相光学光谱提供核磁共振技术的光学类似物。