OP: Building Artificial Photonic Materials from Nanoscale Optical Matter

非技术性描述：光子材料是由小于光波长的粒子组成的图案化结构，这些粒子以各种有序的排列方式人工结合在一起。通过改变颗粒的大小、形状和周期性排列，可以控制材料的光学性质，如颜色、光泽甚至光的吸收。该项目旨在设计和构建光子材料，包括尺寸仅为几纳米的颗粒。这是通过将光照射到含有大量金属纳米颗粒的流体上来实现的。类似于原子结合形成分子的过程，金属纳米颗粒在流体中结合在一起形成颗粒排列。通过改变流体的流动，可以控制这些光子材料的结构，从而控制它们的光学特性。计算机模拟和实验的结合为培养本科生和研究生提供了丰富的环境。将研究的组成部分纳入现有的本科课程和实验室实验，使学生能够对广泛的材料相关概念有更深入的了解。技术说明：光学物质是一种独特的物质，它是由光场中胶体粒子的纯介观电动相互作用产生的。由于与包含纳米颗粒的光学物质相关的显著不稳定性，先前的研究主要针对基于微米颗粒的结构。本计画的目的在于消除奈米光学物质固有的不稳定性问题，并建立一个利用奈米光学物质建构人工光子材料的范例。该范例依赖于先进的激光束整形技术和光场中强散射等离子体金属纳米颗粒之间的显着介观电动相互作用。有效的模拟模型来阐明集体电动相互作用的多个纳米粒子，揭示平衡结合配置。创建优化的光场以增加纳米级光学物质的空间和时间稳定性。通过光聚合在微流控通道中进一步制备光学物质嵌入的聚合物微粒。这些混合粒子可以作为二维或三维金属-介电超晶格的构建块，从而产生具有定制光学特性的新型光子材料。

Nontechnical description: Photonic materials are patterned constructs consisting of particles, smaller than the wavelength of light, that are artificially bound together in various ordered arrangements. By varying the size, shape and periodic arrangement of the particles it is possible to control material optical properties such as color, shine and even the absorption of light. This project aims to design and build photonic materials comprising particles that are only a few nanometers in size. This is accomplished by shining light onto a fluid containing numerous metal nanoparticles. Analogous to the process of atoms joining to form molecules, the metal nanoparticles bind together in the fluid to form arrangements of particles. By varying the flow of the fluid it is possible to control the structure of these photonic materials, and therefore their optical properties. A combination of computer simulations and experiments provide a rich environment for training undergraduate and graduate students. Incorporating components of the research into existing undergraduate courses and laboratory experiments enables students to develop a deeper understanding of a wide range of materials-related concepts. Technical description: Optical matter represents a unique material arising from pure mesoscale electrodynamic interactions of colloidal particles in an optical field. Due to significant instabilities associated with nanoparticle-comprising optical matter, previous studies have predominately addressed microparticle-based structures. This project aims to eliminate the inherent instability problem and create a paradigm for constructing artificial photonic materials using nanoscale optical matter. The paradigm relies on advanced laser beam shaping techniques and significant mesoscale electrodynamic interactions among strongly scattering plasmonic metal nanoparticles in optical fields. Efficient simulation models are developed to elucidate the collective electrodynamic interactions of multiple nanoparticles, to reveal the equilibrium binding configurations. Optimized optical fields are created to increase the spatial and temporal stability of the nanoscale optical matter. Optical-matter-embedded polymer microparticles are further fabricated in microfluidic channels by photopolymerization. These hybrid particles can serve as building blocks for two- or three-dimensional metal-dielectric superlattices, leading to new types of photonic materials with tailored optical properties.