标题: | 应用反向对准型液晶波板研制可调式相位延迟元件之研究 Design and Fabrication of a tunable phase retardator using anti-parallel liquid crystal plate |
作者: | 郭仲伦 Kuo, Chung-Lun 林烜辉 Lin, Shiuan-Huei 电子物理系所 |
关键字: | 液晶;相位延迟板;可调式相位板;琼斯矩阵;liquid crystal;phase retardator;tunable phase retardator;Jones matrix method |
公开日期: | 2009 |
摘要: | 在本论文中,我们分析并研制可调式相位延迟波板之元件,作为全像资讯储存系统中改变光波偏振态器件之应用。我们选用反向对准的间列型液晶晶胞当作设计的基础,希望利用外加电压改变液晶晶胞之双折射特性,达到纯相位调制的功能,形成可调式相位延迟板。 首先,我们利用液晶物理理论来分析,在不同外加电压作用下,液晶晶胞内的液晶分子倾角与位置的关系,将此关系加上广义Jones矩阵法则,可计算在不同外加电压下液晶晶胞对入射线性偏振光波产生相位调制的特性,以此为基础设计可调式液晶相位延迟波板。其次,广义Jones矩阵法则也可以让我们分析各种操作参数下,液晶相位延迟板之特性,特别是其视角的问题,本文我们也针对此问题探讨,找到一个较佳的厚度。 完成理论分析后,我们进行光学实验,根据理论分析,首先将制作好的液晶晶胞放置在两个互相垂直的线偏振板之间,并让入射面之液晶分子长轴与穿透轴夹45度角,测量正向入射之光穿透强度对电压的变化,并与理论分析之结果比对,可以得到此液晶晶胞的相位调制特性,并以此设计反向对准液晶相位板作为波板元件的操作参数。其次将入射光改成汇聚的型式,以偏极角椎显微镜的方式,观察视角问题,并与理论比对,得到最佳化设计。 In this thesis, we investigate on the design and fabrication of a tunable phase retardator using anti-parallel (AP) liquid crystal plate for the application on holographic data storage. With applying voltage, birefringence characteristic of liquid crystal cell can be controlled so that the polarization state of light can be switched. Thus, the liquid crystal cell can work as a tunable pure phase retardator. At first, we derive theoretically relationship between the tilted angles of the liquid molecules as a function of the position in liquid crystal cell under different external voltage. Secondly, by using extended Jones matrix method, the phase retardation of input linear polarization wave as a function of the external voltage can be calculated. It is fundament concept to design our device. Furthermore, with help extended Jones matrix method, we can investigate the viewing angle characteristics of the liquid crystal device and then optimize the operation parameters of the liquid crystal cell such as thickness, external voltages for operation of the half-wave and full-wave plates. In experiments, we first prepare the AP liquid crystal cell with different thickness and then place the cell within cross polarizes to form a sandwich structure. By varying voltage across AP cell, we measure transmission of normal incident light. We compare experimental results with theoretic analyses, and then obtain the operation parameters of the device. Then, by introducing an extra lens to converge light into the liquid cell, we measure the transmission of the liquid crystal cell and polarizer sandwich to study about the viewing angle characteristics. With comparison with theoretical analyses, the design parameters of the liquid crystal cell can be optimized. |
URI: | http://140.113.39.130/cdrfb3/record/nctu/#GT079621552 http://hdl.handle.net/11536/42466 |
显示于类别: | Thesis |
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