共查询到20条相似文献,搜索用时 93 毫秒
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用于光互连的一种非线性调制光栅 总被引:1,自引:1,他引:0
将液晶夹在表面刻有浮雕型光栅的两玻璃平板间,构成一种非线性调制光栅。514.5nm波长的Ar离子激光入射到光栅上,光强变化可调制光栅的三级布拉格衍射效率。 相似文献
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针对现有液晶光栅器件存在的光栅常数不能变化、电极尖端放电、边缘效应等缺点,设计了一种可转换光栅常数的液晶光栅。通过控制不同导电区的通断电,使液晶光栅不同区域产生透光与不透光,实现光栅常数的转换;液晶光栅梳状电极端部的圆弧状设计,避免了尖端放电现象,减小了边缘效应的影响。以He-Ne激光为光源,用WGD-8A型组合式多功能光栅光谱仪对所设计的液晶光栅器件进行了测量,结果表明:通过控制导电区的变化实现了光栅常数的转变,在2~3.4 V电压驱动下,具有3种不同光栅常数的液晶光栅的1级衍射光强逐渐增强,且其衍射光强的差值不断增大,达到了预期设计目的。设计的液晶光栅在视差栅栏、光栅尺等方面有好的应用前景。 相似文献
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用简易易行的方法对液晶光阀(LCLV)的工作特性曲线作了测量,包括光阀在正像,反转像和微分像状态读出光强与写入光强的响应曲线,以及不同写入光照度下液晶层透过率与工作电压的关系曲线,对所得结果的分析揭示了这方面以及未曾深入研究的液晶光阀非线性转换的特性,由此为光阀的很多新用途提供了坚实的实验基础,指出了进一步探索的方向。 相似文献
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本文提出了用液晶空间光调制器制作复合相位光栅、产生三维光阱阵列的新方案.在本方案中,首先将一维矩形光栅转变为能够产生纵向光阱阵列的环形光栅,再把环形光栅和二维矩形光栅组合成复合光栅.根据现有空间光调制器的技术参数,模拟仿真设计了产生5×5×5光阱阵列的光栅,以普通功率的高斯光波为输入光,正透镜聚焦衍射光,计算输出光强分布,结果表明:在透镜焦点附近获得具有很高峰值光强和光强梯度的三维光阱阵列,囚禁冷原子的光学偶极势达到mK量级,对原子的作用力远大于原子的重力.用大功率激光作为输入光波时,产生的光阱阵列也能用于囚禁Stark减速后的冷分子. 相似文献
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液晶空间光调制器能够方便地用于制作各种衍射型光学元件, 但液晶空间光调制器存在分辨率有限的缺点, 本文提出了用液晶空间光调制器制作相位型光栅, 产生一维和二维光阱阵列的新方案, 用迭代傅里叶级数算法优化设计光栅的相位分布, 在不改变空间光调制器硬件参数设置的情况下, 充分利用和发掘了空间光调制器的优点, 同时又能较好地回避其所存在的缺陷. 根据现有的空间光调制器的技术参数, 模拟仿真设计光栅, 计算光强分布, 结果表明: 用大失谐、小功率激光照明, 能够产生具有很高峰值光强和光强梯度的光阱阵列, 囚禁冷原子的光学偶极势达到mK量级, 对原子的作用力远大于原子的重力. 相似文献
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Vinyltriethoxysilane based inorganic–organic glasses dispersed with 4′-n-pentyl-4-cyanobiphenyl nematic liquid crystal are designed to fabricate a new type of gel glass dispersed with liquid crystal. Scanning electron microscopy shows that the nematic liquid crystal phase, occupying the interconnected cavities, is continuously embedded in the inorganic–organic matrixes. The effect of the nematic liquid crystal weight concentration on the morphology is investigated. The differential scanning calorimetry shows that the nematic-isotropic transition temperature depends on the nematic liquid crystal weight concentration. The Raman spectra show that there are no obvious Raman frequency shifts, compared with pure nematic liquid crystal. The in situ diffuse reflectance FTIR spectra show that the integral intensity of bands of hydroxyls has not varied. 相似文献
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A.G. Maksimochkin S.V. Pasechnik V.A. Tsvetkov D.A. Yakovlev G.I. Maksimochkin V.G. Chigrinov 《Optics Communications》2007,270(2):273-279
A simple experimental method and a set-up to control light beams in the plane of liquid crystal (LC) cell is developed. The main idea of the method is the reflection and the refraction of light beams propagating in a plane of LC layer from the boundary, which separates the regions of a liquid crystal cell with different director orientations and refractive indices. This boundary can be produced by electric field applied to the LC layer with a planar homogeneous orientation. The disclination lines that separate the extremely sharp changes of LC orientation can be also used for this purpose. The possibility of discrete deflection of light beam from the initial direction is shown. A computer simulation confirmed that the proposed experimental geometry was most suitable to control intensity of extraordinary rays propagating in the plane of liquid crystal layer. 相似文献
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We fabricated sub-wavelength patterned gold plasmonic nanostructures on a quartz substrate through the focused ion beam (FIB)
technique. The perforated gold film demonstrated optical transmission peaks in the visible range, which therefore can be used
as a plasmonic color filter. Furthermore, by integrating a layer of photoresponsive liquid crystals (LCs) with the gold nanostructure
to form a hybrid system, we observed a red-shift of transmission peak wavelength. More importantly, the peak intensity can
be further enhanced more than 10% in transmittance due to the refractive index match of the media on both sides of it. By
optically pumping the hybrid system using a UV light, nematic−isotropic phase transition of the LCs was achieved, thus changing
the effective refractive index experienced by the impinging light. Due to the refractive index change, the transmission peak
intensity was modulated accordingly. As a result, an optically tunable plasmonic color filter was achieved. This kind of color
filters could be potentially applied to many applications, such as complementary metal-oxide-semiconductor (CMOS) image sensors,
liquid crystal display devices, light emitting diodes, etc. 相似文献
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In this Letter, we present an electrically tunable holographic waveguide display(HWD) based on two slanted holographic polymer dispersed liquid crystal(HPDLC) gratings. Experimental results show that a see-through effect is obtained in the HWD that both the display light from HWD and the ambient light can be clearly seen simultaneously. By applying an external electric field, the output intensity of the display light can be modulated,which is attributed to the field-induced rotation of the liquid crystal molecules in the two HPDLC gratings.We also show that this electrically tunable performance enables the HWD to adapt to different ambient light conditions. This study provides some ideas towards the development of HWD and its application in augmented reality. 相似文献
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针对蓝相液晶显示器中的暗态漏光特性, 采用时域有限差分方法模拟计算了胆甾相液晶的平面态和焦锥态以及蓝相II态液晶的透射和反射特性, 得到了它们在正交和平行偏振片之间的漏光, 并提出了计算等效旋光能力的公式以比较它们的旋光能力. 通过对比焦锥态和蓝相液晶的旋光能力和漏光特性发现, 采用焦锥态替代蓝相液晶而得到良好的暗态特性是一种可行的方法. 通过研究它们的布拉格反射特性, 得知蓝相液晶的布拉格反射与平面态相似, 但反射强度小, 焦锥态无明显的布拉格反射特性. 相似文献
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V. A. Loiko U. Maschke V. Ya. Zyryanov A. V. Konkolovich A. A. Miskevich 《Optics and Spectroscopy》2011,110(1):110-118
We considered light scattering by a polydisperse ensemble of droplets of a nematic liquid crystal. To model light scattering
by a monolayer of polymer-dispersed spherical droplets of a nematic liquid crystal with cylindrical symmetry of its internal
structure, we proposed a semianalytical modeling method. The method is based on interference approximation of the theory of
multiple wave scattering, anomalous diffraction approximation, and effective-medium approximation. The method takes into account
cooperative optical effects in concentrated, partially ordered layers and can be used to analyze the small-angle structure
of the intensity of scattered radiation in relation to the concentration, size, polydispersity of liquid crystal droplets,
orientation of their optical axes, and refractive indices of the liquid crystal and polymer. The obtained relations can be
applied to solving direct and inverse problems of light scattering in composite liquid crystal materials using data of polarization
measurements. We present graphical results of solving the direct problem for components of the polarization vector of scattered
wave. These results illustrate the formation of an angular structure for monolayers with a high concentration of polydisperse
droplets of the liquid crystal in the range of small scattering angles (0 < θ
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≤ 8°). 相似文献
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基于透射式液晶的电光特性, 设计和开发了一套基于液晶和数字处理器 (digital signal processor, DSP)的强光局部选通智能网络摄像机系统. 系统基于透射式液晶和DSP开发板(核心芯片TMS320DM642)技术, 利用DSP控制液晶驱动, 实现液晶单个像素透过率的控制, 将强光的透过率下降2个数量级; 该系统利用另一块DSP 开发板(核心芯片TMS320DM6437)实现将处理后的强光视频信号进行网络传输与实时存储到PC机中, 实现选通智能网络摄像. 该系统24 h所需存储硬盘容量8.648 Gbit, 所用液晶的延迟时间25.5 ms, 电路延迟时间17 μs. 在光强大于2.2×105 lx的强光照射下, 得到系统的选通视频实验结果. 结果表明该系统能解决强光下普通CCD高动态范围摄像机出现局部曝光过度而不能分辨细节的成像问题, 实现了CCD的高动态范围成像.
关键词:
液晶
DSP
光强透过率
高动态范围 相似文献