向列相液晶中相位光栅光束耦合特性  

Beam coupling of phase grating in nematic liquid crystals

作　　者：任常愚[1] 丁红伟[1] 尹向宝[1] 程俊廷[2] 

机构地区：[1]黑龙江科技学院理学院,哈尔滨150027 [2]黑龙江科技学院现代制造工程中心,哈尔滨150027

出　　处：《黑龙江科技学院学报》2012年第1期68-72,共5页Journal of Heilongjiang Institute of Science and Technology

基　　金：黑龙江省自然科学基金项目(A200915);黑龙江省教育厅科学技术研究项目(12511493)

摘　　要：为了研究向列相液晶中相位光栅光束耦合特性,从理论上分析了相位光栅的光束耦合和衍射规律,采用掺杂C60垂直排列的向列相液晶(5CB),厚度为20μm的样品,进行二波耦合(TBC)实验,研究动态衍射和光束放大特性。结果表明:相位光栅的衍射强度分布呈现明显不对称。根据取向光折变效应表面电荷调制机制和电场作用下的Carr-Helfrich效应对此现象给出定性解释,认为非对称光强分布来自于样品中产生的非对称相位光栅。液晶中非正弦调制的空间电荷场产生了非对称相位光栅。Aimed at investigating the beam coupling characteristics of nematic liquid crystal phase grating, this paper offers a detailed theoretical analysis of beam coupling of phase grating and diffraction properties and describes the study on dynamic diffraction and beam amplification properties, drawing on the 20 ixm-thick sample which is C60-doped homeotropically aligned nematic liquid crystals（ 5CB ） and the two beam coupling（TBC）. The results show the occurrence of evident asymmetry in the distribution of the diffractive intensities. The paper features a qualitative explanation for the occurrence, according to the light-induced surface-charge modulation mechanism and the Carr-Helfrich effect in the presence of an applied electric field and concludes that the asymmetric distribution is due to the asymmetric phase grat- ing in the sample. The space-charge field of the non-sinusoidal modulation in liquid crystal leads to the asymmetric phase grating.

关 键 词：非线性光学 向列相液晶 相位光栅 光束耦合 

分 类 号：O734[理学—晶体学]