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1.
基于液晶空间光调制器的光栅衍射效率   总被引:5,自引:5,他引:0  
基于Jones矩阵理论和液晶弹性自由能理论,分析计算了扭曲向列型液晶空间光调制器(TN-LCSLM)的复振幅调制特性.以显示一维矩形光栅为例,详细计算了不同输入输出偏振器配置下的一级衍射效率.数值计算结果和分析表明,在加输出偏振器和不加输出偏振器两种情况下都存在一个具有最大一级衍射效率的取向配置.  相似文献   

2.
任常愚  孙秀冬  裴延波 《光子学报》2009,38(7):1667-1670
利用琼斯矩阵(Jones matrix) 方法对C60掺杂向列相液晶中光栅衍射选择性进行分析.给出两束p 偏振光在液晶样品中产生相位全息光栅的透射矩阵,通过探测光的矢量和光栅透射矩阵的琼斯矩阵运算,可以探测衍射光束的偏振态与入射光偏振态的关系.分析发现对于p 偏振的探测光,透射光和正、负一阶衍射光的偏振态均为p 偏振,且正、负一阶衍射效率相同;对于s 偏振的探测光只有透射光存在,可见记录的相位光栅表现出光栅衍射的选择性.  相似文献   

3.
聚合物分散液晶光栅的衍射特性的研究   总被引:9,自引:4,他引:5  
任洪文 《光学学报》1998,18(5):31-634
报道了一种由聚合物分散液晶膜与具有周期性条状电极结构板结合的新型光栅器件,借助于聚合物分散液晶膜的电光特性,这种栅对入射光的散射或衍射取决于对其施加的电压,即它是电场可调的,实验结果显示出当驱动电压超过器件器件阈值电压时,衍射光的强度和衍射斑的可见级次被电场调制,而且它能入射光的线性偏振态变为椭圆偏振态。  相似文献   

4.
为了提高聚合物/液晶(HPDLC)光栅的衍射效率并改善光栅的表面形貌,研究了表面垂直取向处理对HPDLC光栅的影响。首先,研究了表面垂直处理对液晶分子的取向作用,发现垂直取向层对液晶的锚定作用随着盒厚的增加而逐渐减弱,取向层的作用范围大概在3μm ~5μm之间;其次,对相分离程度进行了实验表征,结果表明,随着液晶盒厚度的增加,相分离开始的时间越来越快,并且分离程度也越来越彻底。最后,讨论了表面垂直取向对 HPDLC光栅衍射效率的影响,随着盒厚的增加,相分离出来的液晶微滴形成连续的区域,光栅的衍射效率逐渐升高,当盒厚增加到一定程度,其衍射效率和无取向处理的光栅接近。当盒厚过大时,垂直取向处理对HPDLC光栅散射损失并没有太大的改善,只有当盒厚适中(12μm)时,光栅的衍射效率最高,散射损失最小。  相似文献   

5.
田勇  潘煦  王长顺  张小强  曾艺 《物理学报》2009,58(10):6979-6984
利用偏振全息记录的方法在一种含偶氮侧链的液晶聚合物薄膜中写入了二维偏振光栅.实验采用两束正交偏振的532 nm线偏光作为写入光,在样品同一点上分别记录了相互垂直的两个一维偏振光栅,继而对所构成的二维偏振光栅的特性进行了研究.实验结果表明:二维光栅的衍射效率比一维光栅低,其偏振特性是两个一维光栅元特性的叠加;二维光栅衍射效率对入射光偏振态的依赖性和光栅的偏振转换性质来源于材料中线双折射和圆双折射的共同作用. 关键词: 偏振全息 二维光栅 偶氮液晶聚合物  相似文献   

6.
紫外光诱导液晶相位光栅   总被引:2,自引:2,他引:0  
刘绍锦  凌志华 《光子学报》2008,37(8):1675-1678
使用紫外光诱导取向技术制作了可转换的液晶相位光栅,通过光掩模两次曝光的方法形成光栅条纹.这种光栅制作工艺较为简单,不需要上下基板精确的对准,驱动电压较低.采用He-Ne激光器和光探测器进行测试,结果表明,衍射效率具有电场调制性并出现同预测一致的衍射条纹.对液晶光栅的偏振特性进行了研究,利用琼斯矩阵和衍射理论对液晶相位光栅衍射强度进行了分析和模拟计算.  相似文献   

7.
把夹预聚物分散液晶的玻璃用菲林掩膜遮盖,在紫外灯下进行弱准直光曝光,使液晶和聚合物产生相分离,形成聚合物分散液晶光栅。并采用偏光显微镜对光栅的形貌进行检测,利用激光笔对光栅的电光特性进行测定,证明衍射效率具有电场可调谐性。实验方法简单易操作,现象明显,在光栅常数较大时可以明显看到衍射效果,对液晶物理专业基础实验的教学具有参考意义。  相似文献   

8.
亚波长光栅的偏振闪耀特性   总被引:5,自引:3,他引:2       下载免费PDF全文
 使用琼斯矩阵的方法推导了连续结构亚波长光栅的衍射方程,给出了光栅衍射效率表达式,对偏振特性与衍射特性进行了研究。发现连续结构亚波长光栅仅存在3个衍射级,总衍射效率为100%,且衍射效率可在衍射级间任意分配,0级的偏振态与入射光的偏振态相同,±1级衍射光偏振态与入射光无关,-1级为左旋圆偏振光,+1级为右旋圆偏振光。通过设置入射光偏振态与光栅相位延迟等参数,可使光栅具有闪耀特性,据此可用于设计高效偏振光分束器和偏振光开关。  相似文献   

9.
陈兆震  徐则达 《物理学报》2010,59(5):3264-3272
用双光束干涉法在一种新的聚合物材料IAC-4上刻写正弦相位型光栅,实现了光栅耦合光波导,并研究了该光波导对不同偏振态的入射光的传播特性,对光栅的形成进行了理论分析,对光波导的传播常数进行了数值计算,并对该波导光栅在导光的光强调制和方向控制及其在集成光学方面的应用进行了讨论,最后对任意入射角的光栅方程进行了理论探讨. 关键词: 波导光栅 有机聚合物 平板光波导 集成光学  相似文献   

10.
在向列相液晶中掺杂质量分数约0.2%的偶氮侧链型聚合物制成偏振敏感材料,使用正交圆偏振光记录了具有圆各向异性的一维偏振全息光栅,用线偏振光探测偏振全息光栅,得到正,负一级衍射光也为线偏振光,且偏振态与探测光和零级偏振态相互正交,可以运用琼斯矩阵理论加以解释.偏振全息光栅可由外加电场控制衍射级的变化,即在外加电场作用下,正、负一级衍射产生了90°的相位差.在频率6.05 Hz、电压2.2 V的外场作用下,衍射级的极值振荡变化.  相似文献   

11.
A high-speed controllable polarizing filter has been developed to eliminate obstructive polarized light reflected from glass and watery surfaces for image pickup in video media program producing and marine dynamic remote sensing. In this device, the polarization plane of incident light is rotated through 0°, 45°, 90° or 135° by an electrically-controllable polarization rotator composed of 45° and 90° twisted nematic liquid crystal cells, and the polarization component of reflected light is absorbed by a fixed polarizing film. It selectively absorbs more than 80% of incident white light linearly polarized in an arbitrary direction. With the drastic reduction of reflected light, the object images hidden by the bright reflected light are clearly captured in real time. Another type of polarizing filter, using a guest-host liquid crystal cell instead of the polarizing film, controls light absorption as well as polarization angle.  相似文献   

12.
宋静  马骥  刘永刚  宣丽 《光子学报》2007,36(6):1028-1030
采用光敏预聚物、向列相液晶和光引发剂混合物体系,在不同温度条件下制备全息光栅.利用红外光谱、光学显微镜、He-Ne激光器对预聚物和光栅进行测试.实验结果表明,光栅的衍射效率随制备温度的升高先增加后减小.对实验结果进行分析,发现它与光聚合反应体系的特性有很好的对应关系,同时深入探讨了制备温度对光栅形貌及电光特性的影响.  相似文献   

13.
李文萃  刘永刚  宣丽 《物理学报》2011,60(4):46101-046101
为了提高全息聚合物分散液晶光栅的衍射效率并降低其驱动电压,改善光栅的电光特性,研究了表面平行摩擦取向对全息聚合物分散液晶光栅电光特性的影响.理论分析认为,改善相分离结构和降低液晶微滴之间的有序度差异是优化光栅电光特性的根本所在.由于进行表面取向处理后的液晶和单体之间达到扩散匹配,使得相分离的程度大幅提高,在衍射能力增强的同时驱动电压也实现了大幅下降,而且,表面取向作用也使光栅内的液晶分子均匀排列,降低了液晶微滴之间的有序度差异,从而减少了光栅的散射损失.实验结果表明:进行取向处理后的光栅其衍射效率由传统光 关键词: 全息聚合物分散液晶 衍射效率 驱动电压  相似文献   

14.
应变液晶散射偏光片的试制   总被引:1,自引:0,他引:1  
范志新  郑永磊  刘洋  杨磊  高攀 《光学技术》2012,38(4):473-476
介绍了聚合物分散液晶(PDLC)和应变液晶(SLC)以及散射偏光片的概念,实验制备了应变液晶散射偏光片样品,样品由两张胶片夹层聚合物分散液晶膜在紫外光固化过程中施加剪切应力所形成。给出了样品偏光显微镜照片和可见光分光光度计偏光特性光谱分析。实验结果表明,应变液晶散射偏光片样品外观半透明,在正交偏光场中转动样品有颜色变化,通过样品观察液晶显示器屏幕,在不同角度下有透射和散射作用,在偏光显微镜中观察样品有衬垫料被拉动的痕迹,光谱分析显示样品在绿光550nm波长处最大透光率T∥≈50%,最小透光率T⊥≈5%,偏振度P≈82%。实验结果对于研制实用的拉伸液晶散射偏光片具有参考意义。  相似文献   

15.
陈婷  冯仕猛 《光学学报》2008,29(9):1805-1811
提出一种研究螺旋液晶光学特性的数学处理方法.螺旋型液晶可当作N层双折射材料晶片叠合而成,而相邻晶片的光轴依次旋转一个小角度.在光学转换矩阵中引入复数来研究螺旋型液晶光学性能,给出了相关的数学处理方法.研究了线性偏振光在螺旋液晶中的传播特性,并给出了光经过螺旋液晶后电场强度的矩阵表达式.研究发现,如果入射光波长等于螺旋液晶螺距,线偏振光经过右螺旋液晶后是左旋圆偏振光.理论上分析了螺旋液晶对可见光选择性反射机理.  相似文献   

16.
The scheme and operating principle of a new polarizing optical microscope for observing physical fields on object surfaces are described for the first time. New functions of the microscope are achieved because its optical scheme includes a liquid-crystal space-time light modulator, which achieves the contact of the surface under study with a layer of nematic liquid crystal. Examples and prospects of application of this microscope in photonics are considered.  相似文献   

17.
A data projector using three liquid crystal display panels has a complex optical system. The illuminating optics separate the beam from a light source into three primary colors and separate those into opposite polarizations using multi-layer films and prisms. A reflection grating with the period of subwavelength has high diffraction efficiency for p polarized light and high regularly reflectance for s polarized light. The diffraction angle of a grating largely depends on the wavelength, because a diffractive optical element (DOE) has large chromatic dispersion. The grating with the period of subwavelength can separate the unpolarized light into polarization components effectively using its polarization dependency and can separate white light into color components using its chromatic dispersion simultaneously. The grating makes the optical system simpler and smaller than those with conventional devices. In this paper the efficiency of polarization separation for the grating is calculated by a rigorous analytical method. Next, the condition for color separation is calculated by Snell#x0027;s law, and an optical system using a grating that performs polarization and color separation is proposed. Experimental results of the DOE fabricated are well matched with those of this simulation.  相似文献   

18.
An optically switchable, polarization-independent holographic polymer dispersed liquid crystal (H-PDLC) transmission grating is demonstrated by adding azobenzene-LC and chiral molecules into the H-PDLC formulation. The optical switchable mechanism is from the trans-cis photoisomerization of the doped azobenzene-LC, which modulates the refractive index of the LC rich area. The dependence of the diffraction efficiency of the H-DPLC grating without chiral molecules on light polarization suggests that the orientation of LC directors within the droplet is ellipsoidal and uniaxial. However, the addition of chiral molecules into the H-PDLC formulation helps the formation of isotropic and non-uniaxial LC directors within the droplets. The polarization properties of the grating are investigated and analyzed by the coupled and modified coupled wave theory with a model of sinusoidal dielectric modulation. The results show that the addition of chiral molecules changes the LC phase from nematic to chiral-nematic, where the grating efficiency, which is modulated by the photoinduced phase transition, is independent of the polarization of incident light. Our findings may help improve optical systems that utilize non-polarized light.  相似文献   

19.
In this experimental work, photofabrication of a surface relief grating (SRG) on poly[(methyl-methacrylate)-co-(DR1 methacrylate)] copolymer was used align liquid-crystal molecules in parallel. The interference pattern of circularly polarized Ar+ laser beams was used for this purpose, and the dynamic diffraction efficiency of the grating was measured at the same time. Then, the polymeric layers aligned by SRG were used to fabricate a homogeneous aligned liquid-crystal cell. The SRG-induced optical anisotropy of the empty cell and the cell filled with the well-known 5CB nematic liquid crystal was investigated by polarizing microscopy. In addition, the SRG-induced dichroism was studied by polarized UV-Vis spectrophotometry. Finally, the SRG-induced dichroism and optical anisotropy were compared for four different incidence angles. This alignment technique could have useful applications in in-plane switching LC displays.  相似文献   

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