EAGER: Measuring near-field nanoplasmonics fields using super-resolved far-field optics

EAGER：使用超分辨远场光学测量近场纳米等离子体场

基本信息

批准号：
1646621
负责人：
Shimon Weiss
金额：
$ 16.8万
依托单位：
University of California-Los Angeles
依托单位国家：
美国
项目类别：
Standard Grant
财政年份：
2016
资助国家：
美国
起止时间：
2016-09-01 至 2019-02-28
项目状态：
已结题

来源：
https://www.nsf.gov/awardsearch/showAward?AWD_ID=1646621&HistoricalAwards=false
关键词：
EAGER Measuring near field nanoplasmonics

项目摘要

With support from the Chemical Measurement and Imaging Program, Professors Weiss and Neuhauser at the University of California-Los Angeles are developing a new imaging tool to measure local surface plasmon field intensity near nanometer-sized structures. It is known that sometimes when the incoming light illuminates a surface immobilized with small metal features, the electrons in the metal can oscillate back and forth together and form a "wave" ? the so called "surface plasmon". Surface plasmon is an important optical phenomenon and has been widely used in many real world applications, including the dark red color in medieval stained-glass windows that are seen in an old buildings ?the color comes from the visible light interacting with gold nanoparticles embedded in the glass. In order to better utilize the surface plasmon phenomenon, it is important to understand how it is distributed around imperfect nano-structures. Modern science advancement allows scientists to estimate the distribution of surface plasmon field intensity with computer simulation programs, but direct measurements of such field intensity, especially around imperfectly prepared nano-structures, are challenging and have not been fully realized. Professors Weiss and Neuhauser are developing a way to directly measure surface plasmon intensity near a small surface structure by monitoring the blinking rate of certain types of inorganic particles. This method would allow them to map the field intensity at a very high spatial resolution. It is also very fast and inexpensive as compared with other methods currently in development. During this 18-month grant period, both groups are focusing on (1) placing the inorganic particles around nanometer-sized features on a surface and (2) studying how the placement of these particles may be used to map the local EM field intensity. They are applying this imaging technique to study how molecules move near a surface or how a reaction happens on a metal nanoparticle. The graduate students in two groups are involved in both experimental and theoretical components of research. Both professors are also actively engaged in encouraging talented high school student to be enrolled in graduate programs, in particular from underrepresented minority groups. The ability to simultaneously superresolve plasmonic field strengths over a large region is unique and desirable. Such approach will deepen the understanding of and control over plasmonic systems, and will broaden the impact of plasmonics. The novel probing technology Professors Weiss and Neuhauser are working uses the dependence of the blinking statistics in quantum dots on the electric field strength to resolve plasmonic field strengths well below the diffraction limit. The methods negate complications typical of localizing dipole emitters near a metallic nanostructure. A theoretical framework based on modeling of the quantum dots response with time-dependent density functional theory in deterministic or stochastic variants is also used to construct simplified building blocks. A computationally simplified building-blocks based modeling then allow simulations of a very large number of quantum dots and plasmonic structures simultaneously, mimicking the on-going experimental systems. By optimizing the theoretical and experimental tools developed here, the detailed electric field map of ~100x100 micrometer-squared size regions may be measured in quick succession. The imaging method, if successful, could benefit many applications that rely on the ability to measure field strengths below the diffraction limit, ranging from biology, to high speed integrated circuits, to optical computing. Additionally, the software developed for the experiments and for the theory studies provides an approachable tool for analyzing and predicting field strengths in heterogeneous regions. Professors Weiss and Neuhauser intend to disseminate the research tools developed to a broad community through freely available software packages.

在化学测量和成像项目的支持下，加州大学洛杉矶分校的 Weiss 和 Neuhauser 教授正在开发一种新的成像工具，用于测量纳米尺寸结构附近的局部表面等离子体场强度。众所周知，有时当入射光照射固定有小金属特征的表面时，金属中的电子可以一起来回振荡并形成“波”？所谓的“表面等离子体”。表面等离子体激元是一种重要的光学现象，已广泛应用于许多现实世界的应用中，包括在古老建筑中看到的中世纪彩色玻璃窗中的深红色？这种颜色来自可见光与嵌入其中的金纳米颗粒的相互作用。玻璃。为了更好地利用表面等离子体现象，了解它如何分布在不完美的纳米结构周围非常重要。现代科学进步使科学家能够通过计算机模拟程序来估计表面等离子体场强度的分布，但是直接测量这种场强度，特别是在制备不完善的纳米结构周围，具有挑战性，并且尚未完全实现。 Weiss 和 Neuhauser 教授正在开发一种通过监测某些类型无机颗粒的闪烁率来直接测量小表面结构附近的表面等离子体强度的方法。这种方法将使他们能够以非常高的空间分辨率绘制场强图。与目前正在开发的其他方法相比，它也非常快速且便宜。在这 18 个月的资助期内，两个小组都专注于 (1) 将无机颗粒放置在表面上纳米尺寸的特征周围，以及 (2) 研究如何使用这些颗粒的放置来绘制局部电磁场强度。他们正在应用这种成像技术来研究分子如何在表面附近移动或反应如何在金属纳米颗粒上发生。两组研究生均参与实验和理论研究。两位教授还积极鼓励有才华的高中生入读研究生课程，特别是来自代表性不足的少数群体的高中生。在大范围内同时超分辨等离子体场强度的能力是独特且令人渴望的。这种方法将加深对等离激元系统的理解和控制，并将扩大等离激元学的影响。 Weiss 和 Neuhauser 教授正在研究的新颖探测技术利用量子点中闪烁统计数据对电场强度的依赖性来解析远低于衍射极限的等离子体场强度。这些方法消除了将偶极发射器定位在金属纳米结构附近的典型复杂性。基于确定性或随机变体中的时间相关密度泛函理论的量子点响应建模的理论框架也用于构建简化的构建块。然后，基于计算简化的构建块的建模可以同时模拟大量量子点和等离子体结构，模仿正在进行的实验系统。通过优化这里开发的理论和实验工具，可以快速连续测量约 100x100 平方微米尺寸区域的详细电场图。如果成功，这种成像方法将有利于许多依赖于测量低于衍射极限的场强的能力的应用，从生物学到高速集成电路，再到光学计算。此外，为实验和理论研究开发的软件为分析和预测异质区域的场强提供了一种易于使用的工具。 Weiss 和 Neuhauser 教授打算通过免费提供的软件包向广泛的社区传播开发的研究工具。