Investigating Fundamental Quantum Limits of Nonlinear Susceptibilities and Devices

0354736 Kuzyk将在最基本的层面上了解器件材料的非线性光学响应的极限。将采用理论、实验和文献调查相结合的方法来解决这个问题。因此，新的范例将被开发出来，这将为研究人员提供制造更好的器件材料的配方。理论方法是使用和规则来非常笼统地理解在制造优化的光学材料中最重要的问题。虽然系统的细节并不重要，但需要一些关键参数，如前两个激发态能量和两三个跃迁矩来测试该方法的有效性。这些将通过各种线性和非线性光谱学实验来确定。PI过去的研究表明，非线性磁化率有一个理论极限；所有测量过的分子都低于这个极限。这项建议的一部分是使用高阶矩的求和规则和非截断级数来扩展这些计算，以了解可能被利用的不同类型的系统是否存在更高的限制。例如，以前的工作主要考虑了非线性极化率的对角张量分量。这项工作的很大一部分理论方面将是开发一套完整的非对角求和规则，并将它们应用于三维系统，以确定这是否是实现更大非线性的有效途径。理论研究的一个中心主题将是了解可以通过使用新型复合结构(如金属增强器、量子局域模型和三维分子中的对称性)放大非线性响应的系统。虽然关于这些重要概念中的每一个都有单独的大量文献，但求和规则将为以最优方式将这些片段组合在一起提供指导原则。此外，对于每种技术，将使用求和规则来计算适当的器件优值的极限，将使用线性吸收光谱、电吸收光谱和激发态荧光等实验来表征分子的量子态，这将在微观层面上检验计算的有效性。除了与其他研究人员合作生产的新分子外，已知分子还将使用我们的测量技术和理论进行表征。这组结果将被用来确定哪些分子属性对非线性响应的影响最大。(1)智力上的好处：这项建议结合了实验和理论，应用了非常基本的量子力学概念来理解光学设备材料的性能极限。拟议的研究将指导化学家设计新材料，为物理学家/材料科学家制造新结构提供新的范例，并为工程师开发新器件提供新的范例。应该强调的是，总和规则适用于所有材料。虽然这项研究的重点是有机物，因为可以设计出大量的材料，但这项研究也将影响无机系统。(2)更广泛的影响：华盛顿州立大学位于华盛顿州东部和爱达荷州西部的交界处。这是一个农村地区，有经济困难的居民，有印第安人保留地(最近的两个是Nez Perce和Coeur D‘Alene保留地)，以及移民农场劳工的孩子，其中有很大比例的拉丁裔、美洲原住民和其他代表性不足的群体。这些将是外展计划的目标群体。学生和教师将接触到这项研究；并将向学校提供软件，使他们能够参与数据分析。就技术广度而言，提出的基础科学涵盖了广泛的光学技术和所有材料类别。受影响的领域包括电信、计算、显示器、内存和传感器-任何基于光与材料相互作用的应用程序。该奖项由电气和通信系统司和国际科学与工程办公室联合支持。

0354736KuzykAn understanding of the limits of the nonlinear-optical response of device materials will be developed at the most fundamental level. A combination of theory, experiments, and literature surveys will be used to tackle the problem. As a result, new paradigms will be developed that will provide researchers with recipes for making better device materials.The theoretical approach is to use sum rules to understand in very general terms those issues that are most important in making an optimized optical material. While details of the system are not important, certain key parameters such as the first two excited state energies and two or three transition moments are needed to test the validity of the approach. These will be determined with various linear and nonlinear spectroscopy experiments. Past studies by the PI show that there is a theoretical limit to the nonlinear susceptibility; and, that all molecules ever measured fall below this limit. Part of this proposal seeks to extend these calculations using sum rules of higher moments and using a non-truncated series to learn if there are perhaps higher limits for different kinds of systems that may be exploited. For example, previous work considered mostly the diagonal tensor components of the nonlinear susceptibilities. A large part of the theoretical aspects of this work will be to develop a full set of non-diagonal sum rules and apply them to three dimensional systems to determine if this may be a fruitful avenue for larger nonlinearities.A central theme of the theoretical studies will be to understand systems in which the nonlinear response can be amplified by using novel composite structures, such as metal intensifiers, quantum local field models, and symmetries in three dimensional molecules. While there is a separate large body of literature on each of these material concepts, the sum rules will provide guiding principles in putting together the pieces in the most optimal manner. Furthermore, for each technology, the sum rules will be used to calculate the limits of the appropriate device figure of merit.Experiments such as linear absorption spectroscopy, electroabsorption spectroscopy, and excited state fluorescence will be used to characterize the quantum states of the molecules, which will serve as a test of the validity of the calculations on the microscopic level. In addition to new molecules produced in collaboration with other researchers, known molecules will be characterized with our measurement techniques and theory. This set of results will be applied to determine which molecule attributes have the largest impact on the nonlinear response.(1) Intellectual Merit: Using a mix of experiments and theory, this proposal applies very fundamental concepts of quantum mechanics to understand the performance limit of optical device materials. The proposed studies will guide chemists in designing new materials, provide new paradigms for physicists/materials scientists in making new structures, and engineers to develop novel devices. It should be stressed that the sum rules apply to all materials. While the focus is on organics because of the vast number of materials that can be engineered, this research will also impact inorganic systems.(2) Broader impact: Washington State University is located at the border of Eastern Washington and Western Idaho. This is a rural area with economically disadvantaged residents, Indian Reservations (the nearest two are the Nez Perce and the Coeur D'Alene reservations), as well as children of migrant farm laborers with a large proportion of Latinos, Native Americans, and other under-represented groups. These will be the groups targeted by the outreach program. Students and teachers will be exposed to this research; and, software will be provided to the schools so that they can participate in data analysis. As far as technical breadth, the fundamental science proposed underlies a broad range of optical technologies and all material classes. Areas impacted include telecommunications, computing, displays, memory, and sensors - any applications that operate based on light interacting with a material.This award is jointly supported by the Division of Electrical and Communications Systems and the Office of International Science and Engineering.