Investigations of Switchable Mesoscale Lattices for Photonics

0322878本提案的重点是发现和应用二维和三维结构全息形成的聚合物分散液晶(H-PDLC)，用于创建针对光子晶体(PHC)和衍射光学应用的电可切换中尺度晶格。H-PDLC材料具有开关速度快(100ms)、可见光和近红外吸收低、衍射效率高、折射率分布可调、一步法制备简单、成本低廉等优点。提出了一种利用351 nm或532 nm全息光刻产生光学晶格的方法，通过光扩散分相过程永久捕获全息聚合物分散液晶中的光学晶格。PI将执行时间多路复用曝光技术，以模拟自然并构建人造晶格。其中一种已被证明具有激光效应的晶格被称为液晶蓝相(BP)。BP在螺旋胆甾相和等营养相之间的温度范围内是稳定的，在等营养相中发现了高度有序的3D晶格。其他提出的晶格结构包括钻石晶格、叠加晶格、准晶格和超晶格，重点研究了它们的应用潜力(如激光、波导、应变计)。通过与妇女科学与工程协会(WISE)和全国黑人工程师协会(NSBE)的地方分会合作，可以通过论坛和演讲向科学和工程领域代表性不足的群体广泛传播研究成果。此外，还将为K-12的学生和教师创建一个模块，演示晶格如何自组织，并将晶格的形成与幼儿的艺术相结合。布朗大学将组织一次关于光子学和企业家精神的会议，将教职员工、产业界、学生和投资界聚集在一起，向大学研究人员展示如何从他们的基础光子学研究中潜在地创造价值。

0322878CrawfordThis proposal focuses on discovery and application of two- and three-dimensionally structured holographically formed polymer dispersed liquid crystals (H-PDLC) for the creation of electrically switchable mesoscale lattices targeted at photonic crystal (PhC) and diffractive optical applications. H-PDLC materials exhibit fast switching (100 ms), low absorption in the visible and near IR, high diffraction efficiency, tunable refractive index profiles, and simple and inexpensive one step fabrication. Holographic-lithography at 351 nm or 532 nm is proposed to generate optical lattices that are permanently captured in holographic-polymer dispersed liquid crystals through a photo-diffusion phase-separation process. The PI will perform temporal multiplexing exposure techniques to mimic nature and build artificial lattices. One such lattice, which has been shown to exhibit lasing, is known as the liquid crystal blue phase (BP). The BP is stable on the temperature scale between the helical cholesteric phase and the isotrophic phase, where a highly ordered 3D lattice is found. Other proposed lattice configurations include the diamond lattice, superimposed lattices, quasilattices, and superlattices, with investigations focusing on their application potential (e.g. lasing, waveguides, strain-gauges). By cooperating with the local Chapters of the Women in Science and Engineering (WiSE) and the National Society for Black Engineers (NSBE), the research findings can be broadly disseminated to underrepresented groups in science and engineering through forums and presentations. In addition, a module will be created for K-12 students and teachers to demonstrate how lattices self organize, and to integrate lattice formation with art for younger children. A conference will be organized on photonics and entrepreneurship at Brown University to bring together faculty, industry, students, and the investment community to show university researchers how to potentially create value out of their basic photonics research.