Molecular Nanopolaritonics

分子纳米极化子学

• 批准号: 0810003
• 负责人: Daniel Neuhauser
• 金额: $ 42万
• 依托单位: University of California-Los Angeles
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2008
• 资助国家: 美国
• 起止时间: 2008-08-01 至 2012-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0810003&HistoricalAwards=false
• 关键词: Molecular; Nanopolaritonics

Daniel Neuhauser of UCLA is supported by an award from the Theoretical and Computational Chemistry program for work to develop a theoretical methodology to understand molecular nanopolaritonics. The project is intended to unify the treatment of radiation and matter in such a way as to efficiently and accurately describe systems of arbitrary physical geometry and electronic structure. Prior to this reseach, combined plasmon-matter studies typically utilized multipole mode expansions on the plasmon-carrying structure, which although simple, are unable to accurately capture arbitrary geometries or field singularities. Using TDDFT for the whole system, on the other hand, is prohibitively expensive computationally. The PI is, thus, extending previous simulations, both in terms of method used and applications chosen for testing those methods. The research starts with FDTD-type algorithms (to be modified for near-field applications), and continues on to discrete-dipole studies, and finally implements embedding formalisms using Hydrodynamic Tensor DFT. The molecular part is being described by a real-time TDDFT algorithm, and treated non-linearly as to capture the multiharmonic and frequency mixing characteristics of the system.The drive towards ever smaller scales for radiation features has led to the new field of plasmonics in which light transport along metal nanoparticle arrays and waveguides is studied at distances as small as a few nanometers (nm). At the same time, electronic structure calculations have also reached the nm size scale, so that the distinction between radiation and matter scale is being blurred out. This has led to a variety of studies where dipolar emission coupling of a few plasmons and excitons are considered, with interesting resonance, field- and spatial-dependence and more. Matter-radiation on the nanoscale (nanopolaritonics in short) is now ripe for a realistic description of both near-field radiation and molecules. The PI and his group are merging Maxwell's near-field description with modern studies of electronic dynamics, to simulate combined matter-radiation (plasmon-exciton, i.e., polariton) systems on the nanoscale. Some applications being considered are: gating of radiation transfer, specifically in large scale plasmonic systems with birefringence effects, including questions about whether molecules can control these systems, an application with possible use in imaging; nonlinear selective microscopy on the nanoscale -- a field with potentially huge impact for sensing applications from engineering to medicine; conversion of electromagnetic near-field energy to physical motion on the nanoscale, which will have practical importance in any field requiring motion control; photovoltaics where plasmons are hoped to reduce absorber sizes; matching of near and far fields, which could conceivably be affected by molecular motion; and the development of plasmon logic circuits .

加州大学洛杉矶分校的丹尼尔诺伊豪泽获得了理论和计算化学项目的奖项，以表彰他在开发理解分子纳米极化的理论方法方面的工作。 该项目旨在统一辐射和物质的处理，以便有效和准确地描述任意物理几何和电子结构的系统。在这项研究之前，等离子体-物质组合研究通常利用等离子体携带结构上的多极模式展开，虽然简单，但无法准确捕获任意几何形状或场奇点。另一方面，对整个系统使用TDDFT在计算上是非常昂贵的。 因此，PI扩展了以前的模拟，无论是在使用的方法和应用程序选择测试这些方法。 该研究从FDTD型算法（将修改为近场应用）开始，并继续进行离散偶极子研究，最后使用流体动力学张量DFT实现嵌入形式。分子部分由实时TDDFT算法描述，并进行非线性处理，以捕获系统的多谐波和频率混合特性。对辐射特征的越来越小的尺度的驱动导致了等离子体激元学的新领域，其中光传输沿着金属纳米颗粒阵列和波导被研究在小到几纳米（nm）的距离。与此同时，电子结构计算也达到了纳米尺度，以至于辐射和物质尺度之间的区别正在被模糊。这导致了各种各样的研究，其中一些等离子体激元和激子的偶极发射耦合被认为是有趣的共振，场和空间依赖性等。纳米尺度上的物质辐射（简称nanopolaritonics）现在已经成熟，可以对近场辐射和分子进行现实描述。PI和他的团队正在将麦克斯韦的近场描述与电子动力学的现代研究相结合，以模拟组合的物质辐射（等离子体激子，即，极化激元）系统。正在考虑的一些应用是：辐射转移的门控，特别是在具有双折射效应的大规模等离子体系统中，包括关于分子是否可以控制这些系统的问题，这是一种可能用于成像的应用;纳米尺度上的非线性选择性显微镜-一个对从工程到医学的传感应用具有潜在巨大影响的领域;电磁近场能量转换为纳米尺度上的物理运动，这将在任何需要运动控制的领域具有实际重要性;等离子体有望减小吸收体尺寸的光致发光;近场和远场的匹配，这可能会受到分子运动的影响;以及等离子体激元逻辑电路的发展。