对称结构光子晶体表面Tamm态的光学性质

利用传输矩阵理论和等效原理,从能级的角度研究对称结构光子晶体表面Tamm态的光学性质,结果表明:在有限排列周期结构光子晶体中,介质表面可支持表面Tamm态的存在,且轴向传播时通带中出现TM和TE偏振的能级简并现象,离轴传播时从通带边缘分离出来的非简并能级被局域于光子晶体表面而形成了光学Tamm态；表面Tamm态内存在很强的局域电场,而且局域电场在介质界面处分布最强；表面Tamm态内的能量输运,对于低折射率介质可正反两方向输运,且输运速度快,对于高折射率介质只能正向输运,且输运速度较慢,故在高折射率介质界面处形成很强的局域光场。对称结构光子晶体表面Tamm态光学性质可为光子晶体光波导和表面波传感器的研究和设计提供指导。     

光轴任意取向单轴晶体的非正入射工作状态：非正交Jones矩阵

当光线斜入射到光轴任意取向的单轴晶体上时，采用ｏ，ｅ两光线的光矢量本征振动方向为一组非正交基矢。在这组特殊基矢上建立了Ｊｏｎｅｓ矩阵，得到了单轴晶体光学传输特性的较为严格的描述。     

EDTA对KDP晶体光学性质影响

本文探讨了不同掺杂浓度下,EDTA对KDP晶体光学性质的影响。结果表明,高浓度EDTA的KDP晶体光散射有明显的影响,但对光学均匀性和光损伤阈值无明显影响。     

改善石英晶体旋光滤波器次极大的优化设计

为了改善滤波光谱的次极大,提高透过滤波片观察像的衬度,设计了减小次极大光强的石英晶体旋光滤波结构,并从理论上分析了滤波特性。以3级石英晶体旋光滤波器为例,由分析可知,在第3级之后增加1级与第1级或第2级相同的结构,均有效地减小了次极大的光强;比较发现,增加1级第2级的结构效果较好。结果表明,此设计对改善石英晶旋光滤波器次极大应用于观测光谱中提供了理论依据。     

退火对6H-SiC晶体的光学性质及光致发光的影响

利用双光束分光光度计对高温退火前后的掺氮和未掺杂6H-SiC晶体的透射及反射谱进行了分析,发现无论退火前后,两种SiC晶体在紫外区均存在强烈的吸收.在可见和近红外区,尤其是未掺杂SiC样品具有很高的透射率,退火后,两种样品的透射率均明显提高.利用荧光分光光度计研究了退火前后样品的光致发光特性,结果表明:在390 nm Xe灯激发下.两种样品在417 nm和436 nm处均可观察到蓝光发射,417 nm处的发光归结于C簇的发光,436 nm处的发光机理为从晶粒的核心激发载流子转移到晶粒表面,并与其上的发光中心辐射复合;同时,掺氮SiC在575 nm处还存在发光峰,为氮掺入后引起的非晶SiC的发光,在325 nm Xe灯激发下,525 nm处存在发光峰,其详细发光机制有待进一步研究.     

铌酸锂晶体电子结构和光学性质计算

使用基于从头计算平面波赝势法的CASTEP量化软件计算了铌酸锂(LiNbO3)晶体的电子能带结构和线性光学系数,采用耦合微扰方法(CPHF)计算了铌酸锂晶体的非线性光学系数.折射率和倍频系数的计算结果与实验结果基本符合,计算表明铌酸锂晶体中Nb原子的4d轨道电子态和O原子的2p轨道电子态发生了明显杂化.通过分析铌酸锂晶体的价带顶和导带底电子态密度的组成特点可知这些轨道电子态的杂化是其非线性光学效应的主要来源,同时计算还表明铌酸锂晶体中Li-O键具有明显的共价键性.     

GaSb晶体的高能N~＋注入及其光学性质

本文用低温光致发光光谱（ＰＬ）、椭圆偏振光谱（ＳＥ）、背散射及沟道技术（ＲＢＳ／Ｃ）、扫描电镜技术（ＳＥＭ）等研究了２ＭｅＶ高能Ｎ＋注入Ｇａｓｂ晶体损伤及其光学性质．结果表明高能Ｎ＋注入Ｇａｓｂ晶体不会产生反常膨胀（Ｓｗｅｌｌｉｎｇ），通过合理的退火可使注入样品晶格得到很好恢复．椭圆偏振光谱能准确反映注入样品晶格损伤情况，并与背散射结果吻合．用有效介质模型（ＥＭＡ）对椭偏谱进行似合可对注入损伤有定量的了解．     

非线性光学晶体MMTWMP的热学和光学性质的测定

报道了一种新型非线性光学晶体：二水合二N-甲基-(-吡咯烷酮合硫氰酸汞锰(MMTWMP)。用热重分析法、差示扫描量热法、吸光光度法、红外和粉末衍射光谱研究了它的热学和光学性质。它属于四方晶系，晶胞参数为α-1．21294，C=0．822.38nm，V=1．21127nm^3。MMTFMP晶体具有较好的物理化学稳定性。它的紫外截止波长为360nm。比硫氰酸汞锰，MnHg(SCN)4(MMTC)紫移了13nm。它在404nm的透过率为44．82％，比MMTC高了17．46％。     

LiH电子结构与光学性质的密度泛函计算

采用基于密度泛函理论的平面波超软赝势方法计算了LiH晶体的电子结构和光学性质,给出了电子态密度、介电函数、吸收系数、复数折射率等计算结果,并对计算结果进行了分析.介电函数的虚部、吸收光谱、折射率等的峰值位置存在一一对应关系,这表明它们之间存在着内在的联系,与电子从价带到导带的跃迁吸收有关.

Abstract：

Electronic structure and optical properties of LiH crystal were investigated by using plane-wave ultra-soft pseudopotential method based on density functional theory. Electronic state density, dielectric function, absorption coefficient, and the complex reflectivity index of LiH crystal were calculated and analyzed. The peaks of the imaginary part of dielectric function, absorption spectra and complex reflectivity index of LiH crystal are corresponding with each other. Such results are related to the transition absorption of electrons from valence band to conduction band.     

Cathodoluminescence Study of Orientation-Patterned GaAs Crystals for Nonlinear Optics

Orientation-patterned (OP) GaAs crystals are very promising for their use in nonlinear optical applications. In particular, mid-infrared and terahertz lasers can be generated by frequency conversion from shorter-wavelength sources. However, the quality of the crystals is crucial for high conversion efficiency, as the presence of defects with electrooptical signatures can contribute to optical losses. The study of these defects is a step toward the improvement of OP-GaAs crystals. We present here a spectroscopic cathodoluminescence study of the distribution of the main defects. Tentative relations between defects and the optical propagation losses are discussed.     

基于矩阵光学的光镊设计

光镊已经成为研究单分子生物物理特性的一个基本工具, 因而光镊设计是一个极为重要的课题。光镊捕获光路一般由激光器、扩束系统、光束调控系统、共焦系统、光束耦合系统和大数值孔径的物镜组成, 通过保持物镜后瞳充满度来实现光镊稳定性。本文根据几何光学, 利用矩阵光学进行光镊捕获光路计算, 得到了各个透镜间距、透镜和光束调控系统距离、物镜后瞳处光斑大小与光束调控系统处光斑大小的关系、光束调控系统处光斑大小和入射激光光斑大小的关系。本文计算结果表明光镊横向位置和物镜高度无关, 并指出了物镜后瞳位于成像透镜后焦面、光束调控系统位于共焦系统后透镜像方焦面处, 才能在光镊阱位纵向操控时保持物镜后瞳充满度不变。本文工作为光镊设计和调整提供了非常简洁而有效的理论指导。     

辛几何在矩阵光学中的应用

本文根据光场辛结构的特性,把描述非对称光学系统的4×4阶矩阵定义为辛的,直接给出了分块矩阵元之间的6个关系式。     

双曲正弦平方-高斯光束在单轴晶体中垂直于光轴的传输

基于光束在单轴晶体中的傍轴矢量传输理论,对双曲正弦平方-高斯光束在单轴各向异性晶体中垂直于光轴的传输做了研究,得到了一般的解析传输公式,并用数值计算方法分析了该光束的传输特性。研究表明:由于晶体的各向异性,其原来的偏振特性将不再保持,仅沿x方向偏振的初始场分量衍生出y分量;随着传输距离的增加,非寻常光沿x轴和z轴的偏振场慢变振幅均减小,光强峰值也随之减小。此外,双曲正弦平方-高斯光束在单轴晶体中垂直于光轴传输时,光束参数β取值不同,光强呈现不同的分布状态。     

Unique Electro‐Optical Properties of Liquid Crystals Designed for Molecular Optics

Antiferroelectric order has been known to exist in liquid crystals since more than a decade and is now an intensely studied field of research. The great application potential of antiferroelectric liquid crystals has especially been demonstrated in sophisticated flat‐panel display prototypes, which nevertheless have not yet reached manufacturing, due to the severe intrinsic problem of folds in the smectic layers, which drastically limit the achievable contrast, and which seem impossible to circumvent. By proper molecular design, we have developed and tested a new generic class of antiferroelectric materials that present an elegant solution to this problem. Their optical properties make them unique not only among liquid crystals but among electro‐optical materials in general. The design of this generic class, which we call orthoconic, also gives an illustrative example of the physical meaning of the addition of tensorial properties. Normal surface‐stabilized antiferroelectrics are optically positive biaxial crystals, with an effective optic axis along the smectic layer normal. The surprising optical property of the corresponding orthoconic antiferroelectric can be formulated as a theorem: When the tilt directions in adjacent smectic layers are made perpendicular to each other, the material becomes negatively uniaxial with the optic axis lying perpendicular to the smectic layer normal. The electro‐optic effect in such a material is based on the fact that the optic axis can be switched between three mutually orthogonal directions, corresponding to zero, negative, or positive values of the applied electric field.     

A New Poly-Si TFT Current-Mirror Pixel for Active Matrix Organic Light Emitting Diode

A new poly-Si thin-film-transistor (TFT) current-mirror-active-matrix-organic-light-emitting-diode (AMOLED) pixel, which successfully compensates for the variation of the threshold voltage as well as mobility in the excimer laser annealed poly-Si TFT pixel, is designed and fabricated. The OLED current$(I_ OLED)$of the proposed pixel does not depend on the operating temperature. When the temperature of pixel is increased from 27$^circhboxC$to 60$^circhboxC$, the$I_ OLED$of the new pixel circuit composed of four TFTs and one capacitor increases only about 1.5%, while that of a conventional pixel composed of two TFTs and one capacitor increases about 37%. At room temperature, nonuniformity of the$I_ OLED$in the proposed circuit was also considerably suppressed at around 9%. We have successfully fabricated a 1.2-in AMOLED panel$(hbox96 times hbox96 times hboxred green blue)$to evaluate the performance of the proposed pixel. A troublesome residual image caused by the hysteresis phenomenon of the poly-Si TFT was almost eliminated in the proposed AMOLED panel as a result of current programming.     

基于动态矩阵控制的主动队列管理算法

针对Internet系统,通过对流体流模型的分析,提出了一个新的预测模型.该模型形式简单,参数的计算相对容易,并且能根据当前的网络情况有效的预测拥塞窗口的变化.结合动态矩阵控制 (Dynamic Matrix Control,DMC) 理论,提出了一种新的主动队列管理算法——DMCAQM 算法,给出了DMCAQM 的详细设计过程,稳定性分析和参数选取原则.大量不同网络环境的仿真实验表明DMCAQM 算法是有效的.与PI、RaQ 和REM 等算法相比较,DMCAQM 有收敛速度快、队列抖动小的优点.同时,由于DMCAQM 的采样间隔相对较大,而算法实现简单,所以计算量小,占用的路由器资源更少.     

主动光学技术在薄镜面中的应用及算法研究

针对采用准zemike多项式拟和法求主动光学校正力的过程中,因为准zernike多项式的不正交性造成求解误差大、求解不稳定的问题,提出了对准zernike多项式进行householder变换的方法.该方法不同于传统的最小二乘法和Gram-Schmidt正交化方法,它避免了因构造法方程组出现严重病态而引入的计算误差.根据该方法求出主镜的刚度矩阵,然后采用阻尼最小二乘法求校正力.基于此方法对直径为400mm的实验镜进行了多次仿真计算,计算结果表明,采用householder变换后波面拟和精确,求解稳定,校正效果较好.     

用散射短阵法求二维光子晶体缺陷内的场分布

本文介绍了一种新颖而高效的计算位于二维光子晶体缺陷中电磁场模式的方法，这一方法是通过将光子晶体中每个柱体的散射场叠加起来而得到所求场的，用该方法计算了两例具体的光子晶体结构，得到了满意的结果。     

Scattering Matrix Method for Modeling Defect Modes in 2-D Photonic Crystals

A novel and numerically efficient treatment of electromagnetic modes localized at defects in two-dimension (2D) photonic crystals is presented in this paper. The method represents the fields in terms of scattered fields by each column of the photonic crystals. With the method, the field distributions in two photonic crystal structures are calculated with satisfying results.