物性参数对液晶偏振光栅特性的影响

Influence of physical parameters on the properties of liquid crystal polarization grating

随着现代社会对数据存储容量和信息处理速度要求的不断提高,更加小型化、集成化的平面光学器件受到了广泛的关注。作为一种典型的可以进行几何相位调制的液晶器件,液晶偏振光栅具有衍射效率高、偏转角度大、响应时间短等优势,已经展现出了非常大的应用潜力。然而,目前液晶偏振光栅在设计制备过程中还存在许多与电光性能相关的问题,限制其走向实际应用。实现液晶偏振光栅衍射特性的调控需要满足一些先决条件。本文通过选取合适液晶偏振光栅的弹性连续体模型,主要研究改变液晶材料的物性参数如弹性常数、介电常数等在强、弱两种锚定条件下对临界盒厚和阈值电压的影响。并给出了针对不同应用要求的液晶偏振光栅的制备过程中,关于液晶材料物性参数选择的理论参考依据。

With the demand on increasing data storage capacity and information processing speed in the modern society,more compact and integrated planar optical devices have received widespread attention.As one of the typical liquid crystal(LC)devices to modulate geometric phase,LC polarization gratings have shown great application potential in optical systems due to the advantages such as high diffraction efficiency,large deflection angle,and short response time,etc.However,some of the problems related to electro-optical performances have not yet been overcome in the current manufacturing process of LC polarization gratings,limiting its practical application.The control of diffraction characteristics of LC polarization gratings is subject to certain preconditions.In this work,by optimizing the elastic continuum model used to analyze the LC polarization grating,the influence of LC physical parameters(elastic constant,dielectric constant,etc.)on the critical cell thickness and threshold voltage,under the strong and weak anchoring conditions were investigated,providing the theoretical support for the selection of LC materials with suitable physical parameters for LC polarization gratings toward different applications.