Colloidal plasmonic nanostructures for enhanced emission and optical nonlinearity.

在美国国家科学基金会化学部大分子、超分子和纳米化学项目的支持下，该项目将合成胶体细长金纳米粒子和银纳米粒子，并将研究它们与半导体和聚合物材料的集成。通过这些材料的可控组装，该项目将生产纳米级非线性光开关和快速单光子源。三个独立的研究重点将被追求：(1)将金双金字塔涂覆或嵌入具有光学克尔效应的介质中，以寻求快速的纳米级非线性光开关。介质的强度相关折射率与折射率敏感共振电场增强之间的反馈可以支持亚皮秒时间尺度上的光学双稳性。(2)皮秒单光子源将利用双金字塔的大且各向异性场增强，加速其辐射速率并定义其偏振态。(3)由于银在光学频率上是比金更好的等离子体材料，而且目前还没有窄等离子体共振的小型单分散银天线的合成方法，因此PI将采用合成策略来生产具有良好形状产率和单分散性的单晶银纳米棒，特别是使用低功函数金属的低电位沉积（UPD）来控制表面能量和稳定性。在美国国家科学基金会化学部大分子、超分子和纳米化学项目的支持下，该项目将影响三个独立的科学领域：胶体合成、等离子体材料和教育。胶体合成是一个仍处于起步阶段的领域，该项目将专注于开发新的方法来控制颗粒的形状及其组装成更复杂的结构。电子处理已经深刻地改变了社会，光的处理已经在电信中无处不在，并且有望继续发展。超快纳米级光开关和单光子源必须作为这一进展的一部分来开发，这个项目将化学生产和表征这两个基本但必不可少的元素。该研究项目将培养两名博士生成为物理和化学交叉的跨学科研究领域的前沿技术和创造性科学家。PI还将开发课程材料和光学演示，以使贫困的高中学生和广大公众了解光和胶体材料的特性。

Technical AbstractWith support from the Macromolecular, Supramolecular, and Nanochemistry program in the Chemistry Division at NSF, the PI will synthesize colloidal elongated gold and silver nanoparticles and will study their integration with semiconductor and polymer materials. Through the controlled assembly of these materials, the project will produce nanoscale nonlinear optical switches and fast single photon sources. Three separate research thrusts will be pursued: (1) Fast nanoscale nonlinear optical switching will be sought by coating an Au bipyramid with or embedding it in a medium exhibiting an optical Kerr effect. Feedback between the intensity-dependent refractive index of the medium and the index-sensitive resonant electric field enhancement can support optical bistability on subpicosecond time scales. (2) Picosecond single photon sources will be designed to take advantage of the large and anisotropic field enhancement of a bipyramid, speeding its radiative rate and defining its polarization state. (3) Since silver is a better plasmonic material than Au at optical frequencies and there are no existing synthesis of small monodispersed Ag antenna with narrow Plasmon resonance, the PI will undertake synthetic strategies to produce monocrystalline Ag nanorods with good shape yield and monodispersity using in particular underpotential deposition (UPD) of lower work function metals to control surface energy and stability.Non-Technical AbstractWith support from the Macromolecular, Supramolecular, and Nanochemistry program in the Division of Chemistry at NSF, this project will impact three separate scientific areas: colloidal synthesis, plasmonic materials, and education. Colloidal synthesis is a field still in its infancy and this project will focus on the development of new methods to control both the shape of the particle and its assembly into more complex structures. Electronic processing has changed society profoundly, and the processing of light is already ubiquitous in telecommunications and promises to continue to develop. Ultrafast nanoscale optical switches and single photon sources must be developed as part of this progress, and this project will chemically produce and characterize these two basic but essential elements. The research project will educate two PhD students to become skilled and creative scientists at the frontier in an interdisciplinary research area, intersecting physics and chemistry. The PI will also develop curricular materials and optical demonstrations to bring an understanding of the properties of light and colloidal materials to disadvantaged high school students and to the public at large.