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

该研究计划的总体目标是开发液晶（LC）偏振光栅（PG），用于新型光子元件（菲涅耳光学器件，涡旋光束工具和聚合物激光器），对光的强度，方向，轨道角动量和偏振进行特殊控制。 这些各向异性衍射元件由体相液晶组成，可以由可切换材料或聚合物材料制成，并且效率很高。 第一个目标是开发基于PG的菲涅耳波带片光学器件，其具有非常小的f数、独特的偏振行为和引人注目的可切换透镜装置的潜力。第二个目标是研究有效的和可扩展的螺旋（涡旋）光束工具，基于分叉的PG，具有前所未有的能力来产生和测量轨道角动量。 第三个目标是采用小周期光栅（亚微米）来研究分布反馈效应，使用半导体聚合物来构建有机发光二极管，以及使用掺杂有荧光染料的活性介晶来构建表面发射聚合物激光器。所提出的具有复杂2D轮廓的PG代表了一类新的高效且灵活的菲涅耳光学器件，其具有极小的f数的潜力，将导致新的涡流束工具，可以显着影响量子通信和密码学，激光镊子，光刻显微镜，并可能导致光泵聚合物激光器具有较低的阈值和较高的效率。更广泛的影响：该计划包括研究生/本科课程创新和实验和理论的多学科培训。 与AventWest儿童辅导计划和NCSU科学之家合作，PI将为初中/高中学生举办课后和暑期课程，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.