退火温度对镶嵌于SiO2膜中的Ge纳米晶结构的影响

采用磁控溅射及退火的方法制备了含Ge纳米晶的SiO2复合膜,应用拉曼散射和X射线衍射技术研究不同退火温度下的Ge纳米晶结构.结果表明:Ge纳米晶的结晶温度约为750 ℃.运用声子限域模型(RWL model)对样品的拉曼散射光谱进行拟合,确定出样品中Ge纳米晶的尺寸.通过XRD谱计算复合膜的内部压应力,得出由其引起的拉曼峰位的蓝移量,得出结论:压应力是造成拉曼模拟曲线与实验曲线峰位偏离的主要原因.     

煤介质损失角正切的分形特征

利用分形几何理论对煤的介质损失角正切的特征作了深入的探讨·结果表明,煤的介质损失角正切tgδ具有分形特征;通过类比和实验证实的方法得到了tgδ与f间的定量关系：tgδf(D-d)/2,借此求得了煤分形介质损失角正切维数。     

Optimizing calculation of phase screen distribution with minimum condition along an inhomogeneous turbulent path

When building an experimental platform for light propagation along an inhomogeneous turbulent path,it is very essential to set up the reasonable distribution of phase screen.Based on multi-layered model of phase screen,an iterative optimization algorithm of phase screen position is given in this paper.Thereafter,the optimal position of phase screens is calculated under the Hufnagel-Valley5/7 and Hefei-day turbulence profile.The results show that the positions of phase screen calculated by the iterative algorithm can fit well with the turbulence profile rather than mechanically placed phase screens at equal distance.Compared with the uniform distribution of phase screens position,the residual phase error of the iterative algorithm decreases very significantly.The similarity degree between them is minimal when number of layers is equal to two.     

基于成像清晰度函数的非球面反射镜位置校正实验研究

在具有双曲面、抛物面或椭圆面反射镜的成像光学系统中,反射镜的位置误差通常具有对成像质量影响灵敏的特点.因此,在该类光学系统装调或工作过程中反射镜位置存在误差时需要对该反射镜进行精确调整.目前,反射镜位置校正的方法多基于对系统波前误差的测量,从而判断其位置误差.然而在系统工作过程中可能无法进行光学系统的波前测量,或者需要复杂的光学系统才能实现波前误差的测量.本文以焦平面图像清晰度作为评价函数,采用随机并行梯度下降算法对反射镜位置进行调整,使系统成像质量达到最佳.针对迭代过程中反射镜位置发生变化时图像偏离探测器靶面而无法探测的问题,本文采用了一种反射镜垂直光轴平移和旋转相结合的调整方法.在保证图像位置不变化的条件下对系统像差进行校正.室内实验验证了该方法具有可行性,校正后的成像质量达到衍射极限.     

CuO薄膜的制备及其光伏特性

通过反应磁控溅射在n型硅和玻璃衬底上制备了p型CuO薄膜.使用X射线衍射仪和紫外-可见光-近红外光度计研究了p型CuO薄膜的结构和光学特性,得出其平均晶粒尺寸和光学带隙分别为8 nm和1.36 eV.通过研究其电压-电流关系确定了在p型CuO薄膜和n型硅衬底之间形成了p-n结.在AM 1.5光照条件下p-CuO/n-Si电池的开路电压为0.33 V,短路电流密度为6.27 mA/cm², 填充因数和能量转化效率分别为0.2和0.41%.     

Te/TeO2-SiO2复合薄膜的吸收和非线性光学特性研究

应用分光光度计测量Te/TeO₂-SiO₂复合薄膜的透射光谱和吸收光谱, 在480nm附近观察到Te颗粒引起的等离子体共振吸收峰; 采用Z扫描技术研究了共振(激发波长为532 nm)和非共振情况下(激发波长1064 nm) 不同电位制备薄膜的Te颗粒状态与复合薄膜的三阶非线性极化率的关系. 基于有效介质理论对复合薄膜的三阶非线性效应进行分析, 研究Te颗粒大小对Te/TeO₂-SiO₂复合薄膜的非线性光学性质的影响及其产生机理. 结果表明薄膜制备过电位增大, Te的粒径减小, 颗粒数量多, 颗粒分布趋于均匀, 使得金属颗粒的表面等离子体共振峰红移, 吸收强度增强, 导致三阶非线性光学效应增强, χ⁽³⁾由1064 nm的5.12×10^-7 esu增大为532 nm的8.11×10^-7 esu. 关键词： 碲 二氧化碲 复合薄膜 三阶非线性     

Breather-Type Periodic Soliton Solutions for (1+1)-Dimensional Sinh-Poisson Equation

In this paper,by using bilinear form and extended homoclinic test approach,we obtain new breather-type periodic soliton solutions of the (1+1)-dimensional Sinh-Poisson equation.These results demonstrate that the nonlinear evolution equation has rich dynamical behavior even if it is (1+1)-dimensional.     

Co-focus experiment of segmented mirror

In this paper, an active optics and co-focus experimental system of segmented mirror is built. Firstly, a support structure of segmented mirror is designed and it is verified by simulation to meet the requirement for the experimental system of segmented mirror. In this system, the large de-focus and tilt/tip errors of the segmented mirror are adjusted by observing the density and contrast of interference fringes based on isoclinic interference theory until the defocus and tilt/tip errors are in the detective range of the Shack–Hartmann. Then, the Shack–Hartmann is used to measure them and they are adjusted by actuators. The actuators are controlled by active optics to realize the closed-loop adjustment and maintenance for fine co-focus of segmented mirror. And the interference fringes are utilized to verify the detective precision of Shack–Hartmann. After the co-focus fine-tuning of the segmented mirror, the tilt/tip residual surface error is better than 0.01λ RMS; the defocus residual surface error is better than 0.01λ RMS.     

First light on the 127-element adaptive optical system for 1.8-m telescope

A 127-element adaptive optical system has been developed and integrated into a 1.8-m astronomical telescope in September 2009.In addition,the first light on a high-resolution imaging for stars has been achieved（September 23,2009）.In this letter,a 127-element adaptive optical system for 1.8-m telescope is described briefly.Moreover,star observation results in the first run are reported.Results show that the angular resolution of the system after adaptive optics correction can attain 0.1 arcsec,which approaches the diffraction limit of 1.8-m telescope at 700-900 nm band.     

激光实际大气水平传输湍流畸变波前的功率谱分析Ⅱ: 波前相位与格林伍德频率

分析了整体倾斜像差去除前后大气湍流畸变波前相位的功率谱。 在激光实际大气水平传输实验中, 利用61单元自适应光学系统的哈特曼波前传感器, 测量和分析了大气湍流畸变波前相位的功率谱。 还建立了一种根据实际测量的波前相位功率谱数据估测自适应光学系统变形镜需要控制带宽大小和大气湍流格林伍德(Greenwood)频率的方法。