【作者】 刘静；

【导师】 胡家升；

【作者基本信息】 大连理工大学 ， 测试计量技术与仪器， 2008， 硕士

【摘要】 液晶空间光调制器(Liquid Crystal Spatial Light Modulator，LCSLM)是构成实时光学信息处理、光学相关和光学神经网络等系统的关键主动器件，在光学信息处理研究中发挥重要的作用并有着广泛的应用，其应用领域包括精密测量、三维显示、数字全息、激光波前整形以及光学信息加密系统。本文以此为出发点，介绍了液晶空间光调制器实现光学振幅、相位调制的原理，并利用商用投影显示液晶屏，改进设计其驱动控制电路来构成液晶空间光调制器，最后采用马赫-曾德(Mach-Zehnder)干涉仪来测量分析其相位调制特性。本文就是从以下几个方面来研究：首先，本文从液晶材料的发现与研究现状出发，详细介绍了液晶材料的特性，讨论了液晶分子指向矢的概念，指出其空间分布的决定性因素。介绍了扭曲向列液晶盒(Twist Nematic Liquid Crystal Cell，TN-LCC)的结构及扭曲向列液晶的多种电光效应。在此基础上，利用琼斯矩阵从理论上分析了扭曲向列液晶的复振幅调制特性和输出光偏振特性。根据商用液晶屏的电光调制曲线和其实现强度调制所利用的电压范围，我们提出在原驱动控制电路的基础上加入视频信号处理模块，以去掉原设计中为了实现强度显示目的而引入的直流偏置电压，这样使液晶屏工作在电光调制曲线中强度调制较小的一段驱动电压范围，从而实现纯相位调制。在设计好系统驱动控制电路之后，本文通过实验测定了该空间光调制器系统的相位、强度调制特性。首先介绍了测量LCSLM相位调制特性时所用的光路图及干涉测量原理，并详细介绍了从采集到的干涉图中提取相位信息的过程。在测试过程中，根据光路的特点，对光路中的元件进行调节，使光路满足最佳干涉条件，并使液晶的相位调制最大。接着介绍测量LCSLM强度调制特性的光路图和具体过程。最后给出该空间光调制器系统相位调制和强度调制的结果。更多还原

【Abstract】 Liquid crystal phase-only spatial light modulator plays an important role in optical information process, optical correlation and optical interconnections. It can be used in many fields, such as precision measurement, three-dimensional display, digital holography, laser wave front shaping and optical information encryption system. Hence, it is very important to research it. In this paper, firstly, the principle of phase modulation and intensity modulation is introduced. Then the driver circuit board of commercial liquid crystal display panel is modified and designed based on the reference design module. Lastly, the phase modulation characteristic of this LCSLM is investigated by the Mach-Zehnder interferometer. The main points of this thesis are as follows.Based on the optical properties of the liquid crystal material and the structure of twist nematic liquid crystal cell, the term of molecules direction vector and the influential factors of its spatial distribution are introduced. Then the complex transmission and polarization properties of output light are analyzed by the Jones matrix.According to the relationship between signal amplitude and transmittance, the reference driver circuit is modified and a video signal process module is added in order to get rid of the DC voltage which is beneficial for the purpose of intensity modulation. So the drive voltage range can be limited in the phase-only modulation area.After the driver circuit board designed, a SLM system is built by liquid crystal display panel, driver circuit board, polarizer, analyzer and PC. Then the phase modulation characteristic of this LCSLM is investigated by the Mach-Zehnder interferometer and interferograms captured by CCD are treated in order to extract the phase modulation information. In addition, we should adjust the components to satisfy the interference terms perfectly. The experimental setup and method to measure intensity modulation property are also introduced. Lastly, the phase and intensity modulation property are given in charts.更多还原