Investigations of Switchable Mesoscale Lattices for Photonics

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材料具有切换速度快（100 ms）、可见光和近红外吸收低、衍射效率高、折射率曲线可调、一步制备简单、价格低廉等特点。提出了351nm或532nm的全息光刻技术，通过光扩散相分离过程产生永久捕获在全息聚合物分散液晶中的光学晶格。PI将执行时间复用曝光技术来模拟自然并构建人工晶格。其中一种晶格被称为液晶蓝相（BP），已被证明具有激光效应。在螺旋胆甾相和等营养相之间的温度尺度上，BP是稳定的，其中发现了一个高度有序的三维晶格。其他提出的晶格结构包括金刚石晶格、叠加晶格、准晶格和超晶格，研究重点是它们的应用潜力（例如激光、波导、应变片）。通过与当地科学与工程妇女分会（WiSE）和全国黑人工程师协会（NSBE）的合作，研究结果可以通过论坛和演讲广泛传播给科学和工程领域代表性不足的群体。此外，还将为K-12学生和教师创建一个模块，以演示格是如何自组织的，并将格的形成与年幼儿童的艺术结合起来。布朗大学将组织一次关于光子学和创业的会议，将教师、工业界、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本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.