液晶光取向制备偏振衍射光学元件

衍射光学元件是光学领域的重要内容，该类元件常基于对光强或位相的调制实现，衍射效率较低（＜40.5%）。偏振衍射光学元件因其单衍射级效率可达100%成为近年的研究热点，吸引了科研人员的强烈关注和广泛研究。受制备技术限制，现有的研究还主要集中于光栅、菲涅尔波带片等结构简单的元件。本项目拟依托课题组创新设计的数控微镜阵缩微投影装置，结合光控取向技术在液晶多畴取向图案化方面的独特优势，设计完善一种简单、高效的制备任意指向矢连续变化的微结构取向液晶的技术方法。依托该技术，围绕偏振叉形光栅和偏振艾里模板这两类全新的人工微结构光学元件进行研究，掌握偏振衍射光学元件液晶取向结构的设计原则和取向控制规律，阐明该类元件对光的独特作用机制及其电光调控规律，进而优化元件综合性能，实现电光可调、可任意重构、偏振和波长不敏感的光涡旋产生器和艾里模板的开发，为光场操控带来全新的手段。

Diffractive optical element is fundamental requirement in optical field. This kind of element is commonly based on amplitude or phase modulation of light, inducing a limited diffraction efficiency (＜40.5%). Recently, research on polarization diffractive optical element becomes a hot topic and attracts intensive attentions and wide investigations of scientists, due to their potential of 100% efficiency for single diffraction order. Unfortunately, owing to the fabrication technique limitation, to date, only such elements with simple structures such as gratings and Fresnel zone plate have been demonstrated and investigated. In this project, we try to develop a simple and high efficient method to accomplish arbitrary fabrication of director-varying liquid crystal structures, via combining our home-made DMD based microlithography setup with photoalignment, which facilitates the multi-domain patterning of liquid crystals. Based on this technique, we will develop two novel kinds of diffractive optical element, polarization fork gratings and polarization Airy masks. In this research, we want to understand the rule for the design and fabrication of micro-structured liquid crystals, know their actions on light and explain the mechanism of electro-optical tunability. Furthermore, we will optimize the general performance of these optical elements towards merits of fast tunability, arbitrary reconfigurability and insensitive to both polarization and wavelength. Finally, we will achieve practical optical vortex generators and Airy masks, thus opens a door towards optical field control.