Experimental method for the extraction of intensity profiles by imaging the scattered pattern with a charge-coupled devic

A practicable experimental method for measuring scattering on rough surfaces is reported.The scattered patterns are captured on a screen composed of two pieces of ground glass and then imaged using a chargecoupled device.The scattered intensity profiles are extracted by converting the patterns in real space into the wave vector space.Isotropic and anisotropic samples of the rough backsides of silicon wafer are investigated respectively,and their intensity profiles are measured.The profiles of the anisotropic sample are obtained by reading the pixels on the specific orientation curves.The parameters of the samples are extracted using angle-resolved light-scattering schemes and theories.The results well agree with measurements obtained using an atomic force microscope.     

Properties of Movement and Boiling of Speckles Produced by Moving Objects Illuminated with Partially COherent Light

Properties of movement and the boiling of dynamic partially coherent speckles are investigated.Theoretical analysis of the correlation functions shows that in front of and behind the Fraunhofer plane,the directions of the movement of the dynamics partially coherent speckles are the samp and opposite to that of the object,respectively,The boiling occurs according to a parabolic factor with respect to time separation τ.These properties are observed experimentally by using an elaborately chosen extended source to meet the requirement of intensity and coherence.The boiling of the speckles is measured with the photon counting system,which is refitted for the automatic data acquistition,and the experimental results are confirmed by the theory.     

气/液界面上双萘菁夹心化合物有序超分子结构的组装

研究了气/液界面上双(八-十二烷硫基)萘菁铒{Er[Nc(SC₁₂H₂₅)₈]₂}形成的Langmuir单层膜中的超分子结构. 表面压-面积(π -A)等温线表明该化合物形成了稳定的单层膜. 将其沉积在云母片上, 用原子力显微镜(AFM)进行观察, 表明分子形成了取向高度有序的结构, 聚集体特征长度在100 nm左右(有的长达300 nm), 宽为20~30 nm.用紫外-可见光谱、偏振紫外-可见光谱、小角X射线衍射等对 LB膜进行了研究, 发现分子大环平面与基片平面夹角为54°, 每层厚度为3.53 nm. 研究表明形成的超分子结构由4~6列以面对面堆积形成的柱状体构成.     

二维反射光栅衍射畸变的光散射方法研究

利用光散射方法理论分析了二维反射式正弦光栅衍射场,得到了衍射极大光点的佗置坐标,并讨论了衍射极大光点位置的性质与畸变问题.对于与人射而垂直方向变化的栅线衍射极大光点,给出了畸变的坐标曲线并其进行了数值计算.实验测量正弦反射光栅衍射的光强分布,各级衍射极大光点的位置分布与理论结果很好地符合.     

Experimental study of regional fractal speckle produced in large angle scattering

Using the interference of speckle and the spherical reference wave,we extract the real and the imaginary parts of the complex amplitudes of the speckle in large angle scattering.By calculating the spatial correlation functions of intensity,we find that the speckle has a property of regional fractality,i.e.the fractal exponent equals 1 in a small spatial region and it becomes less than 1 in a bigger region.The empirical analytic expression of the intensity correlation function is gained.The probability density distributions of the intensities and the complex amplitudes show that the regional fractal speckle still obeys zero-mean circular complex Gaussian statistics.     

表面粗糙度的变波矢光散射测量方法的研究

提出了表面粗糙度变波矢光散射测量方法，通过散射光强中心亮点光能量的参数ｌｎ，Ｅ随变化的线性关系来确定粗糙度ｗ，对６块粗糙度不同的硅片背面样品进行了实验测量。     

Ordered supramolecular assembly of bis[3,4,12,13,21,22,30,31-octa(dodecylthio)-2,3-naphthalocyaninato]erbium at the air/water interface

The supramolecular assembly of bis[3, 4, 12, 13, 21, 22, 30, 31-octa(dodecylthio)-2, 3-naphthalocyaninato] erbium complex (Er[Nc(SC12H25)8]2) was fabricated at the air/water interface by Langmuir monolayer technique. Surface pressure-area isotherm indicates that stable monolayer is formed. The monolayer morphology on mica was investigated by atomic force microscopy (AFM). Columnar domains of ca. 100 nm ×(20-30) nm appearing in the micrograph have ordered orientation. Polarized UV-vis spectra and small-angle X-ray diffraction pattern show that the macrocycles tilt in the monolayer. The orientation angle of the naphthalocyanine ring with respect to the substrate was found to be ca. 54°. Each monolayer is ca. 3.53 nm thick. The columnar domain comprises 4-6 rows of columnar supramolecular assemblies where the molecules stack face-to-face.     

角分辩的光散射轮廓及自仿射分形表面的粗糙指数的实验研究

建立了反射式随机表面的光散射特件实验测量系统,利用多幅平均及叠加连接的方法,得出入射角在45°～85°之间不同值时的光散射轮廓.结果表明,随着表面入射角的增加,光散射轮廓的半峰全宽逐渐减小.并且当入射角的增加到一定值时,光散射轮廓出现中央亮斑.由数学上的对称F降函数,推导出光散射轮廓的半峰全宽随散射光波矢的变化关系,从实验测得角分辩的的光散射轮廓中提取了自仿射分形随机表面的粗糙指数.与原子力显微镜测量得到的粗糙指数进行比较,两者符合得很好.     

飞秒激光脉冲经小孔衍射后的近场光强节点

应用数值求解格林函数的方法,计算模拟了飞秒脉冲通过亚波长小孔的衍射光场. 首先将具有高斯时间轮廓的飞秒脉冲展开成一系列简谐光波的叠加,对每一个频率的简谐光波进行数值计算,得到该频率的衍射光场的空间分布, 然后对所有频率的衍射光场进行反傅里叶变换得到光场随时间的变化.分析发现,飞秒脉冲通过小孔后沿界面向小孔两边传播,并且在该传播过程中, 衍射光场会在介质的分界面上和在接近界面的区域中形成光强的节点.     

纳米金属缝透射的FDTD边界问题研究

时域有限差分法(FDTD)可准确的模拟电磁波经任意介质的衍射与散射.本文依据时域有限差分法并引入Lorentz色散模型理论推导了适用于实际金属的时域有限差分法的迭代公式,利用积分的Maxwell方程组对实际金属边界上的电磁场进行了平均处理,保证了金属缝边界电磁场的连续性,纳米金属缝透射光强分布的数值计算结果验证了边界处理的正确性.