Atypical Photonic Slabs by Quasi-2D Colloidal Self-Assembly

准二维胶体自组装非典型光子板

• 批准号: 1105243
• 负责人: Chekesha Watson
• 金额: $ 33.1万
• 依托单位: Cornell University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2011
• 资助国家: 美国
• 起止时间: 2011-07-01 至 2015-06-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1105243&HistoricalAwards=false
• 关键词: Atypical; Photonic; Slabs; Quasi; 2D

Technical: This project will address the challenge of introducing complexity in photonic slab arrangements. Vertical variation throughout the thickness of quasi-2D slabs will be introduced via colloidal processing under confinement. Freezing between two and three dimensions accesses structural transitions in gap regions incommensurate with integral layer spacing of thin particulate films. From confocal microscopy of fluorescent-shell modified particles in wedge cell geometry, the real space phase organization will be investigated as a function of particle morphology, system density and cell height. The synthesis of shape anisotropic colloids will be performed to prepare building blocks for unconventionally ordered solids in addition to crystals under the imposed packing constraints. Quantitative evaluation of order parameters and correlation functions determined experimentally and from Monte Carlo simulations of the confined states will inform simulation models to evaluate the optical properties of the slab patterns and their various inverse embodiments¯ for example, residual volume-, shell-, and skeleton inverse structures. Sol-gel and nanoparticle precursors for solution processing as well as vapor phase depositions will be applied in backfilling and co-assembly routes to inversion to obtain high-refractive index contrast. The project will enhance the understanding of how reduced symmetry, expanded dimensionality, and novel classes of partial order structuring impact light-matter interactions in photonic crystal slabs. To this aim, photonic band structures will be calculated and the relative influence of structural parameters such as positional ordering, orientation ordering, motif morphology, basis complexity, dielectric filling fraction, refractive index contrast on the behavior of photonic bands at high symmetry points in reciprocal space will be explored. Complimentary analysis of mode field distributions will be applied to rationalize the formation of full 2D photonic band gaps. A powerful experimental technique in its infancy for application to photonic slab structures will be used to confirm stop band and band gap frequencies, modified density of photonic states, in addition to the experimental field distribution of photonic modes. Namely, the Electron Energy Loss Spectroscopy technique applied in a Scanning Transmission Electron Microscope will enable the photonic characterization at high spatial resolution. For investigation of refraction properties of the slabs, equal frequency contour plots will also be calculated and the light propagation in-plane through atypical structures will be simulated to determine frequency and directions for left-handed, right-handed, positive- and negative refraction behavior as a function of structural parameter variants. Point source imaging for appropriately indicated configurations defined by self-assembly will be studied to evaluate resolution in the flat lens application of the photonic slab materials. Through this project the structure-property-processing-performance relationships will be established. NonTechnical: This award will enhance undergraduate research opportunities for students in Historically Black Colleges and Universities as well as Women's Colleges. The PI plans to engage undergraduates to conduct research from these institutions through the REU programs associated with the Cornell Shared Facilities. Enrichment will also be offered through conference support for presenting research and for professional development workshops. Lasting relationships with researchers in the home institution will be sought for continued collaboration involving the visiting student and potentially providing additional recruiting opportunities to Cornell's graduate programs. An informal public education project is planned around a distributed research and "Science as Art" model to place images of materials research in public library exhibits which will promote the field. As well, the organization of seminar series hosted by URM graduate fellows to invite distinguished underrepresented minority (URM) faculty for research talks and professional development.

技术：这个项目将解决在光子平板排列中引入复杂性的挑战。准2D板厚度的垂直变化将通过约束下的胶体加工引入。二维和三维之间的冻结在与薄膜的整体层间距不相称的间隙区域中访问结构转变。从共聚焦显微镜的荧光壳层修饰颗粒的楔形单元几何结构，将研究真实的空间相组织作为颗粒形态，系统密度和细胞高度的函数。将进行形状各向异性胶体的合成，以制备非常规有序固体的构建块，以及在施加的堆积约束下的晶体。对由实验和从受限状态的蒙特卡罗模拟确定的序参数和关联函数的定量评估将使模拟模型能够评估板条图案及其各种逆实施例的光学性质，例如剩余体积、壳和骨架的逆结构。用于溶液处理的溶胶凝胶和纳米颗粒前驱体以及气相沉积将被应用于回填和共组装路线以反转以获得高折射率对比度。该项目将加强对对称性降低、维度扩大和新型偏序结构如何影响光子晶体平板中的光-物质相互作用的理解。为此，我们将计算光子能带结构，并探索位置有序、取向有序、模体形态、基态复杂性、介电填充分数、折射率对比度等结构参数对倒易空间中高对称点光子能带行为的相对影响。模场分布的互补分析将被用来合理地形成全2D光子带隙。一种应用于光子板结构的强大的实验技术将被用来确定阻带和带隙频率，修正的光子态密度，以及光子模的实验场分布。也就是说，将电子能量损失谱技术应用于扫描透射式电子显微镜，将使高空间分辨率的光子表征成为可能。为了研究平板的折射特性，还将计算等频率等值线图，并模拟光在平面内通过非典型结构的传播，以确定左撇子、右撇子、正负折射行为的频率和方向作为结构参数变量的函数。将研究通过自组装定义的适当指示配置的点源成像，以评估在光子平板材料的平板透镜应用中的分辨率。通过这个项目，将建立结构-性能-加工-性能的关系。非技术性：该奖项将为历史黑人学院和女子学院的学生提供更多的本科生研究机会。PI计划通过与康奈尔大学共享设施相关的REU项目，邀请本科生从这些机构进行研究。还将通过为提出研究报告和举办专业发展讲习班提供会议支助来提供丰富内容。将寻求与母校研究人员的持久关系，以继续合作，让来访的学生参与进来，并可能为康奈尔大学的研究生项目提供更多的招聘机会。一个非正式的公共教育项目计划围绕分布式研究和“科学作为艺术”的模式，在公共图书馆的展品中放置材料研究的图像，这将促进该领域的发展。此外，还组织了由URM研究生研究员举办的一系列研讨会，邀请杰出的代表不足的少数族裔(URM)教师进行研究讲座和专业发展。