Creating and Probing Optical and Material Nonlinearities in Single Nanoparticles, Dimers, Clusters and Arrays

芝加哥大学的Norbert谢勒在实验物理化学计划的支持下，对基于单个金属纳米颗粒的材料进行了全面的结构功能（即非线性光学响应）测量。 这些材料是单一的银和金纳米球和纳米棒，以及在惰性表面上自发形成的二聚体及其簇，其允许TEM和光学测量。 扩展的一维和二维材料将被创建和研究。 研究目标如下：（1）将光学-空间相关方法的空间分辨率提高到~10 nm，以确定来自纳米颗粒二聚体、簇和阵列的非线性信号的来源，（2）实施一系列非线性光学测量（例如SHG和2-光子荧光干涉测量法，三阶非线性散射干涉测量法，和Sers）用于与来自单个纳米颗粒特征的线性散射进行比较，以量化多纳米颗粒的局部场增强和动力学。粒子共振创建，（3）探索多体光子和一个或两个纳米颗粒之间的（或多点）相互作用以及光阱，以建立由捕获场产生的颗粒之间的力以及作为非线性增强观察到的单光子与多个颗粒的多点相互作用，以及（4）将前三个项目扩展到研究纳米晶体自组装紧密堆积单层阵列和由驻波光捕获产生的有序纳米棒阵列中的等离子体激元耦合和离域。 本研究的总体目标是提高对等离子体激元光学和材料非线性的理解，并最终实现对等离子体激元光学和材料非线性的控制。 将实现的基础科学可能最终导致更好的光学传感器和可调反射镜的发展。 这项研究也可能导致开发用于研究纳米尺度上的生物结构和局部化学成分的探针。

Norbert Scherer of the University of Chicago is supported by the Experimental Physical Chemistry Program to carry out a comprehensive plan of definitive structure-function (i.e. nonlinear optical response) measurements of individual metal nanoparticle-based materials. These materials are single silver and gold nanospheres and nanorods and spontaneously formed dimers and clusters thereof on inert surfaces that allow TEM and optical measurement. Extended one and two-dimensional materials will be created and studied. Research aims are the following: (1) to improve the spatial resolution of the optical-spatial correlation method that has been developed to ~10 nm to allow determination of the origin of the nonlinear signals from nanoparticle dimers, clusters, and arrays, (2) to implement a range of nonlinear optical measurements (e.g. SHG and 2-photon fluorescence interferometry, third-order nonlinear scattering interferometry, and SERS) for comparison with linear scattering from single nanoparticle features to quantify the local field enhancements and dynamics of the multi-particle resonances created, (3) to explore the multi-body (or multi-point) interactions among photons and one or two nanoparticles and an optical trap, to establish the force between the particles resulting from the trapping field as well as the multi-point interaction of single photons with multiple particles observed as a nonlinear enhancement ,and (4) to extend the first three projects to the study of plasmon coupling and delocalization in self-assembled close-packed monolayer arrays of nanocrystals and in ordered nanorod arrays created by standing wave optical trapping. The overall goal of this research is to improve understanding of and ultimately allow control of plasmon-based optical and material nonlinearities.The longer-range motivations of this project are stimulated by the vision of nanoscale optical devices. The fundamental science that will be achieved could ultimately lead to the development of better optical sensors and reflective mirrors that are tunable. This research could lead as well to the development of probes for investigating biological structures and local chemical composition on the nano-scale.