PECASE: Complex Polarization Gratings - Extreme Fresnel Zone Plates, Agile Vortex Beam Tools, and Enhanced Distributed-Feedback

本研究计划的总体目标是开发用于新型光子元件（菲涅耳光学，涡旋光束工具和聚合物激光器）的液晶偏振光栅（pg），该光栅具有对光的强度，方向，轨道角动量和偏振的特殊控制。这些各向异性衍射元件由大块向列lc组成，可以在可切换或聚合物材料中制造，并且效率很高。第一个目标是开发基于pg的菲涅耳带板光学，具有非常小的f值，独特的偏振行为和引人注目的可切换透镜器件的潜力。第二个目标是研究高效和可扩展的螺旋光束工具，基于分叉pg，具有前所未有的生成和测量轨道角动量的能力。第三个目标是使用小周期光栅（亚微米）来研究分布式反馈效应，使用向列半导体聚合物来构建有机发光二极管，并使用掺杂荧光染料的反应介质来构建表面发射聚合物激光器。知识优势：具有复杂2D轮廓的PGs代表了一种新型高效灵活的菲涅耳光学器件，具有极小f值的潜力，将导致新型涡旋光束工具，可能会极大地影响量子通信和密码学，激光镊子，光刻显微镜，并可能导致光泵浦聚合物激光器具有更低的阈值和更高的效率。更广泛的影响：该项目包括研究生/本科生课程创新和多学科实验和理论培训。PI将与AventWest儿童指导计划和NCSU科学之家合作，为中学生和高中生举办课外和暑期课程，涉及动手工程项目。

The overall objective of this research program is to develop liquid crystal (LC) polarization gratings (PGs) for novel photonic elements (Fresnel optics, vortex beam tools, and polymer lasers) with exceptional control over the intensity, direction, orbital angular momentum, and polarization of light. These anisotropic diffractive elements are composed of bulk nematic LCs, can be made in switchable or polymer materials, and are highly efficient. The first goal is to develop PG-based Fresnel zone plate optics, with potential for remarkably small f-numbers, unique polarization behavior, and compelling switchable lens devices. The second goal is to investigate efficient and scalable helical (vortex) beam tools, based on forked PGs, with unprecedented ability to generate and measure orbital angular momentum. The third goal is to employ small-period gratings (sub-micron) to investigate distributed feedback effects, using nematic semiconducting polymers to build organic light-emitting-diodes, and using reactive mesogens doped with fluorescent dyes to build surface-emitting polymer lasers.Intellectual Merit: The PGs with complex 2D profiles proposed represent a new class of efficient and flexible Fresnel optics with potential for extremely small f-numbers, would lead to novel vortex beam tools that could dramatically impact quantum communication and cryptography, laser-tweezers, lithography microscopy, and could lead to optically pumped polymer lasers with lower thresholds and higher efficiencies. Broader Impact: This program includes graduate/undergraduate course innovation and multidisciplinary training in experiment and theory. In collaboration with AventWest Children's Mentoring program and NCSU Science House, the PI will host after-school and summer sessions for middle/high-school students involving hands-on engineering projects.