全息聚合物分散液晶论文：二维全息聚合物-液晶光栅制备的研究

全息聚合物分散液晶论文：二维全息聚合物/液晶光栅的制备研究
【中文摘要】全息聚合物分散液晶(Holographic polymer dispersed liquid crystals, HPDLCs)光栅作为一种新型的光学元件,在计量、无线电天文学、集成光学、光通信和信息处理等许多领域都有着十分广泛的应用。

传统的光栅都是一维的结构,是通过将制备好的样品在两束相干涉光束的光场处曝光,使光敏单体在水平方向上聚合形成相互平行的等宽度等间隔的结构,在样品中只记录了一个光栅；本文中研究的二维光栅可以同时在样品中记录两个光栅结构,相当于在样品中同时记录了正交的两个一维光栅结构,其制备方法是将混合均匀的光敏单体材料和液晶注入液晶盒中,在双束激光干涉处使样品曝光一段时间,然后将样品旋转90度,再曝光一次,使光敏单体
在两个方向上聚合得到。

二维光栅在光入射时形成的衍射图样是空间点阵,除上述的应用之外还可以用于光互联中的分束器,调制器和耦
合器件等,拓宽了光栅的应用范围。

虽然二维全息聚合物分散液晶光栅的应用很广泛,但是目前的制备方法还不成熟,还存在很多问题,主要是光聚合反应中相分离不完全,衍射效率偏低,光栅驱动电压过高,器件稳定性差等。

本文首先对实验体系所用的液晶、化学材料进行选择和研究,分析光聚合反应中的光引发剂的化学重排过程,研究聚合
物与液晶相分离机理；其次,通过改变光照时间、光强等参数、研究各组分在光聚合中所起的作用和影响,增加光聚合的反应程度,以得
到具有清晰的相分离结构和较高衍射效率的二维聚合物／液晶光栅；再次,依据对衍射效率影响因素的分析,选择不同作用的添加剂,提高光反应效率,提高相分离程度；文中选择了含氟单体材料和增塑剂DOP 来改善光栅形貌,以提高光栅的衍射效率,降低光栅的驱动电压；最后,通过设计和改进光路,通过两次曝光法制备了具有良好相分离界面,
具有较高衍射效率和较低驱动电压的二维聚合物／液晶光栅。

最后对光路进行调整,制备了小周期的二维的聚合物／液晶光栅。

【英文摘要】Holographic polymer dispersed liquid crystals (HPDLCs) gratings as a novel optical components,have a very wide range of applications in the measurement, radio astronomy, integrated optics, optical communication, information processing and many other areas.The traditional grating is one-dimensional structure and prepared by beam exposure in two-beam interference field to make the photosensitive monomer polymerization in the horizontal directionz and form the equal-distance and equal-interval stripe parallel to each other.and only records one grating. A two-dimensional grating researched in this article can be simultaneously recorded two gratings in the samples, is equivalent to simultaneously recorded a orthogonal structure of the two one-dimensional grating in the sample. The method to prepare two-dimensional grating is mixed photosensitive monomer into the liquid crystal
material and then injected into the sample cell. Put it into two-beam interference field and make it exposure.after 15s rotate 90 degrees and make it exposure another until the photosensitive monomer polymerization completely in the horizontal and the vertical direction of the sample. The diffraction pattern formed by two-dimensional grating is the space lattice when the incident light go through the cell, Besides the application of the above.it can be used for the beam splitter of optical interconnection, modulators and coupling devices, broaden the scope of application.Although the application of two-dimensional holographic polymer dispersed liquid crystal grating is comprehensive, but the preparation method is not mature, there are still many problems at present. Mainly the phase separation is not complete in the polymerization, low diffraction efficiency,and the drive voltage is too high, poor device stability.The liquid crystal and chemical materials used in the system are selected and studyed first in this experimental.and then analyzed the chemical rearrangement process of polymerization photoinitiators.and study the phase separation mechanism of polymer and liquid crystal. Secondly.study the role and impact of each component by changing the irradiation time, light
intensity and other parameters in the photopolymerization, in
order to increase the degree of photopolymerization and obtain
the two-dimensional diffraction polymer/liquid crystal
grating with clear separation structure and higher efficiency. Thirdly, based on the analysis to the factors influenced diffraction efficiency, chose different additives to improve
the efficiency of light reaction and improve the degree of phase separation. In this paper fluorinated monomers and plasticizer
DOP are to selected to improve the grating morphology and the diffraction efficiency, and reduce the driving voltage.Finally,
we design and improve the optical path to prepare the
two-dimensional polymer/liquid crystal grating with good separation interface, high diffraction efficiency and low
driving voltage by two exposure method. At last,we improve the optical path to prepare a two-dimensional polymer /liquid
crystal grating with small period.
【关键词】全息聚合物分散液晶衍射效率驱动电压相分离
【英文关键词】Holographic polymer dispersed liquid crystal Diffraction efficiency Drive voltage Phase
separation
【目录】二维全息聚合物/液晶光栅的制备研究摘要
4-5ABSTRACT5-6目录7-9第一章绪论9-16 1.1 液晶
简介9 1.2 全息聚合物/液晶光栅9-13 1.2.1 全息聚合物分散液晶9-10 1.2.2 研究全息聚合物/液晶光栅的意义
10-11 1.2.3 全息聚合物/液晶光栅的结构及工作原理
11-13 1.3 全息聚合物/液晶光栅的发展及现状13-15 1.4 论文研究目的和内容15-16第二章全息聚合物/液晶光栅的材料及相分离的研究16-36 2.1 引言16 2.2 制备聚合物/液晶光栅的材料的选择16-19 2.2.1 液晶材料的选择16-17 2.2.2 单体材料的选择17-18 2.2.3 光引发剂的选择18-19 2.3 聚合物/液晶光栅的制备19-21 2.4 聚合物/液晶光栅的电光特性
21-23 2.4.1 光栅衍射特性21-23 2.4.2 驱动电压23 2.5 聚合物/液晶光栅的形成及相分离机理研究23-28 2.5.1 引言
23-25 2.5.2 液晶/单体相分离理论分析及动力学扩散过程
25-28 2.6 全息二维光栅28-35 2.6.1 实验光路的设计
28-29 2.6.2 实验模拟29-35 2.7 小结35-36第三章全息聚合物/液晶光栅的制备36-57 3.1 曝光强度对光栅影响
36-40 3.1.1 实验36-37 3.1.2 结果与讨论37-40 3.2 不同曝光时间对衍射效率的影响40-42 3.2.1 实验40-41 3.2.2 结果与讨论41-42 3.3 最优条件下的二维聚合物/液晶光栅的研究42-46 3.4 含F表面活性剂添加对光栅性能的影响
46-49 3.4.1 实验46 3.4.2 结果与讨论46-49 3.5 增塑剂对光栅性能的影响49-53 3.5.1 实验49 3.5.2 结果与讨论
49-53 3.6 二维Bragg光栅的制备及研究53-57 3.6.1 实验
53 3.6.2 结果与讨论53-57第四章结论57-58致谢58-59参考文献59-61。