Nonlinear Spectroscopy: Absorption and Refraction

0524533 Van Stryland该项目研究了各种材料类型中的非线性光学（NLO）吸收光谱和非线性光学折射色散，包括有机材料，纳米晶体半导体和纳米颗粒耦合到有机材料。 最终目标是建立一个由来自世界各地的研究人员提供的材料的NLO属性数据库，通过与理论家的合作，将导致对这些非线性过程的预测能力，这也将允许确定结构/NLO属性关系。PI已经开发了用于NLO材料表征的实验设备，该设备跨越了非常大的光谱（从UV到18 mm）和时间范围（从飞秒到纳秒）。 他开发的主要工具之一是飞秒泵浦/连续探测器，非线性“分光光度计”，它测量频率非简并NLO吸收光谱沿着时间响应（对于应用因果关系确定NLO折射的Kramers-Kronig关系至关重要）。时间响应对于确定NLO响应的源是有用的。此外，他最近开发了一种“白光连续Z扫描”（WLC Z扫描）。该方法利用飞秒连续脉冲的宽光谱，在一次实验中直接测量简并非线性吸收，并在宽光谱范围内分别测量非线性折射的色散。退化的非线性往往是感兴趣的应用，这将允许检查的预测Kramers-Kronig关系。 智力优点：实验方法将提供一个非常大的跳跃，在信息数据库中可用于开发和理解非线性光学相互作用在多种材料和材料类型的基本基础。 有了这个扩展的数据库，观察到的趋势将导致缩放关系，导致验证和/或修改的理论。同时，这些信息为材料研究人员提供了增强（或减弱）非线性响应的反馈。更广泛的影响：该项目将部分资助三名博士的培训。学生（2个在NLO和一个在有机合成化学），以及通过NSF的本科生研究经验计划的几个本科生。 另外一名研究生，通过共同PI哈根的NSF GK-12计划资助，将与当地学校的教师合作，在九年级科学课程中开发光学内容。两个研究生光学课程（光学科学和非线性光学基础）的课程已经丰富了纳入这项工作的信息。

0524533Van StrylandThis project studies the spectra of nonlinear optical (NLO) absorption and the dispersion of NLO refraction in a variety of materials types including classes of organic materials, nanocrystalline semiconductors and nanoparticles coupled to organic materials. The ultimate goals are to build a database of NLO properties of materials provided by researchers from around the world which, through collaboration with theorists, will lead to a predictive capability for these nonlinear processes that will also allow the determination of structure/NLO property relations. The PI has developed the experimental facilities for NLO materials characterization spanning a very large spectral (from the UV to 18mm) and temporal range (from femtosecond to nanoseconds). One of the workhorse tools that he has developed is a femtosecond pump/continuum probe, nonlinear "spectrophotometer" which measures the frequency nondegenerate NLO absorption spectrum along with its temporal response (critical for applying causality to determine Kramers-Kronig relations for the NLO refraction). The temporal response is useful for determining the source of the NLO response. In addition, he has very recently developed a "White-Light-Continuum Z-scan" (WLC Z-Scan). This method utilizes the broad spectrum of a femtosecond continuum pulse to directly measure the degenerate nonlinear absorption and separately measure the dispersion of the nonlinear refraction over a broad spectral range in a single experiment. The degenerate nonlinearities are often the ones of interest for applications, and this will allow for checks on the predictions of Kramers-Kronig relations. Intellectual merit: The experimental methodologies will provide a very large jump in the information database available for developing and understanding the fundamental bases for NLO interactions in multiple materials and material types. With this expanded database, observed trends will lead to scaling relations which lead to validation and/or modification of theory. At the same time this information provides feedback to materials researchers as to methods to enhance (or diminish) nonlinear responses.Broader impacts: This project will partially fund the training of three Ph.D. students (2 on NLO and one in organic synthetic chemistry) as well as several undergraduate students through the NSF Research Experiences for Undergraduates program. An additional graduate student, funded through Co-PI Hagan's NSF GK-12 program, will work with teachers in local schools on the development of Optics content in the 9th grade science curriculum. The curricula of two graduate optics courses (Fundamentals of Optical Science and Nonlinear Optics) have been enriched by incorporation of information from this work.