光致聚合物用于全息光互联光栅的研究

使用光致聚合物做记录介质,记录用于光互联的全息光栅。激光曝光后衍射效率可达5 5 %左右,用紫外光均匀照射后,在10 0℃下烘烤40分钟,衍射效率可达90 %左右。绘制了衍射效率与曝光时间和烘烤时间曲线,制作具有预期衍射效率的用于全息光互联的光栅。     

基于丙烯酸胺基单体的光聚物的全息特性

用实验的方法研究了由丙烯酰胺和亚甲基双丙烯酰胺构成的光致聚合物（光聚物）的全息性能。实验表明，这种由藻红染料敏化的光聚物具有较高的衍射效率、折射率调制度、曝光灵敏度和动态范围，分辨率可达3000lines/mm，是高密度全息存储所需的比较理想的位相型存储材料。     

聚N-乙烯咔唑光敏片的全息记录特性

本文研究了聚N-乙烯咔唑光敏片的全息记录特性,如振幅透过率～曝光量特性、分辨率、衍射效率和感光灵敏度等,并用激光照出了全息象。     

基于数字微镜器件的高分辨率计算全息显示

针对基于数字微镜器件的全息显示分辨率受限的问题,提出了一种大尺寸、高分辨率计算全息显示方法。本文利用计算机渲染或相关变换方法生成高分辨率输入图像,利用菲涅尔衍射算法和傅立叶变换并行计算提升全息图的分辨率,根据数字微镜器件特性进行衍射图像的时空复用与动态融合,有效提升计算全息显示的分辨率与动态效率。实验结果表明,该方法可实现大尺寸、高分辨率的动态全息显示效果,突破了数字微镜器件固有的像素数目及分辨率限制,使用像素分辨率为2K的数字微镜器件可显示8K甚至更高分辨率的重建图像,尺寸可以达到82 mm甚至更大。     

影响全息光刻图形质量的因素

使用矩阵转换方法,对全息光刻中全息掩模衍射效率进行了数值模拟计算,讨论了记录介质显影前后特性的改变和再现时全息掩模复位精度对光刻图形质量的影响,并找出了影响图形质量的主要因素.在此基础上设计了实验系统,最后得到了分辨率基本上只受初始光掩模分辨率限制的光刻图形.     

影响全息光刻图形质量的因素

使用矩阵转换方法,对全息光刻中全息掩模衍射效率进行了数值模拟计算,讨论了记录介质显影前后特性的改变和再现时全息掩模复位精度对光刻图形质量的影响,并找出了影响图形质量的主要因素.在此基础上设计了实验系统,最后得到了分辨率基本上只受初始光掩模分辨率限制的光刻图形.     

绿敏聚乙烯醇/丙烯酰胺体系光致聚合物的配方优化及全息存储特性

采用低分子量成膜剂、补充单体及多种光敏剂,开展了绿敏聚乙烯醇/丙烯酰胺体系光致聚合物的吸收光谱测试、染料浓度及膜层厚度优化研究,获得了高衍射效率及感光灵敏度的绿敏光致聚合物全息记录材料.实验仅需20 mJ/cm2的曝光量即可获得82%的衍射效率,最大衍射效率可达92%以上.测试了该材料的角度选择性,对应的布拉格选择角宽度约为0.57°;开展了角度复用和空间复用全息存储实验,获得了清晰明亮的全息存储样品.     

扫描近场光学显微镜及其初步应用

介绍的扫描近场光学显微镜能够以探针作为亚微米光源或探测器以及受抑全反射等三种工作方式探测样品,在没有样品一探针间距控制的情况下对全息光栅、脂质体以及沸石粉末等进行了扫描成像,并获得了超衍射极限的光学分辨率,其中最优分辨率可达约100nm。     

休斯公司研制新型激光防护镜

休斯飞机公司雷达系统小组研制了一种新的激光防护镜。据说这种防护镜不显著减小能见度而把激光束偏转。采用一种全息衍射光栅，仅把某一预选的波长衍射，同时允许其他波长透射。衍射效率大于99.8%，透射为80%或更高些,视防护的波长而不同。     

自由基胶片的全息记录特性

本文研究了自由基胶片在全息记录中的一些重要特性,包括衍射效率与曝光量曲线、最佳曝光量、感光灵敏度、分辨率、D-logE 特性曲线以及光谱灵敏度等,并和银盐记录介质进行了比较。     

虚像相位阵列的二维成像原理及其应用

虚像相位阵列（VIPA：virtually-imaged phased array）是一种具有大角度色散的光学器件,利用其大角色散的特性,可以用来制作高分辨率滤波器和色散补偿器。将虚像相位阵列和衍射光栅结合实现二维成像是光谱处理领域的重大进步。从二维成像原理出发,详细介绍其在研制高分辨率和高信噪比的光学滤波器、实现复杂的二维光谱处理以及光谱成像等研究领域的最新应用。     

Learning from EPI-Volume-Stack for Light Field image angular super-resolution

Light Field (LF) image angular super-resolution aims to synthesize a high angular resolution LF image from a low angular resolution one, and is drawing increased attention because of its wide applications. In order to reconstruct a high angular resolution LF image, many learning based LF image angular super-resolution methods have been proposed. However, most existing methods are based on LF Epipolar Plane Image or Epipolar Plane Image volume representation, which underuse the LF image structure. The LF view spatial correlation and neighboring LF views angular correlations which can reflect LF image structure are not fully explored, which reduces LF angular super-resolution quality. In order to alleviate this problem, this paper introduces an Epipolar Plane Image Volume Stack (EPI-VS) representation for LF angular super-resolution. The EPI-VS is constituted by arranging all LF views in a raster order, which benefits in exploring LF view spatial correlation and neighboring LF views angular correlations. Based on such representation, we further propose an LF angular super-resolution network. 3D convolutions are applied in the whole super-resolution network to better accommodate the input EPI-VS data and allow information propagation between two spatial and one directional dimensions of EPI-VS data. Extensive experiments on synthetic and real-world LF scenes demonstrate the effectiveness of the proposed network. Moreover, we also illustrate the superiority of our network by applying it in scene depth estimation task.     

一种基于稀布降维处理的高分辨测向方法

针对阵元数一定时大型面阵均匀布阵易产生分辨力与模糊的矛盾问题,提出了一种基于稀布降维的波达方向高分辨估计方法。该方法极大的降低了运算量,同时保持了高分辨的测向精度,较大的改善了角度分嘉串率,计算机仿真证明了该方法的有效性和可行性。     

Overcoming of the diffraction limitations in the receivers of the terahertz frequency range aimed at ultimately high sensitivity and subdiffraction resolution

The existing and original approaches to the overcoming of the diffraction limitations of the noise equivalent power and angular resolution in the receivers of the terahertz frequency range with respect to the ratios of the size of the sensitive receiving element to the radiation wavelength and the input aperture of the receiving camera to the Airy diffraction disk are considered and analyzed.     

Interface strain in organometallic vapor phase epitaxy grown InGaAs/InP superlattices

The spatial distribution of strain in organometallic vapor phase epitaxy grown InGaAs/InP superlattice structures has been studied by varying the thicknesses of the InGaAs well and the InP barrier layers and measuring the strain. High resolution x-ray diffraction rocking curves were used to measure the strain from angular separation between the zeroth-order superlattice peak and the substrate (004) peak. The results are consistent with a compressive strain resulting from arsenic carryover into the InP following InGaAs growth. The strain is not localized at the interfaces but extends into the InP barrier layer. The amount of arsenic carryover increases with the growth time of the InGaAs well.     

多参考光合成孔径DMIPH术的细胞相位重构

为了克服传统光学显微术无法直接提取相位信息的不足而能更准确记录物体高频和低频信息的合成,采用多参考光合成孔径数字显微像面全息系统,并结合角谱算法和最小二乘解包裹算法实现了细胞的相位重构。选取活体细胞组织等相位型生物进行作为实验样本,对其进行定量观察和有效测量。结果表明,多参考光合成孔径数字显微像面全息系统可以有效地应用于3维物体显微结构的振幅和相位重构,能显著地提高记录系统的高频和低频信息在全息图上的合成度,并实现超出系统的衍射极限12.8lp/mm的分辨率。该系统可以有效地实现数字全息系统的超分辨率成像,从而获得细胞显微结构的3维形貌信息和准确的相位分布。     

A two-dimensional Doppler-Radiometer for Earth observation

Compared to synthetic aperture radars (SARs), the angular resolution of microwave radiometers is quite poor. Traditionally, it has been limited by the physical size of the antenna. However, the angular resolution can be improved by means of aperture synthesis interferometric techniques. A narrow beam is synthesized during the image formation processing of the cross-correlations measured at zero-lag between pairs of signals collected by an array of antennas. The angular resolution is then determined by the maximum antenna spacing normalized to the wavelength (baseline). The next step in improving the angular resolution is the Doppler-Radiometer, somehow related to the super-synthesis radiometers and the Radiometer-SAR. This paper presents the concept of a three-antenna Doppler-Radiometer for 2D imaging. The performance of this instrument is evaluated in terms of angular/spatial resolution and radiometric sensitivity, and an L-band illustrative example is presented     

高角度分辨率的信源分离算法

传统的波束形成算法在期望信号和干扰信号来向相近的情况下性能下降,不能很好地完成信源分离,针对此问题提出了一种高角度分辨率的信源分离算法。首先选取一种适合任意阵型的AR模型预测方法进行阵列扩展,然后利用基于独立分量分析的鲁棒性分离算法完成信号分离,通过结合阵列扩展和盲源分离的优点,本文提出的分离算法在不增加实际阵元数目的前提下具备比原阵列更高的角度分辨率。实际数据测试表明提出的算法能够在9元均匀圆阵上分离方位角来向间隔为0.5度的信号。     

Un nouveau matériau pour le multiplexage holographique sur réseau de fibres optiques

Frequency multiplexing, using gratings, in optical fiber systems is now well known. The potentials of holography have already been validated for this kind of application. However, the silver halide photosensitive materials limited the diffraction efficiency and also the achievable angular discrimination. The material we have developed, called optrigelac, is a gelatin doped with ammonium dichromate. This material allows high diffraction efficiencies, up to the theoretical limit of 100 %, with low noise and adjustable angular and wavelength selectivity. The coating, sensitizing and development procedures, and a model relating the final hologram properties to a practical working procedure are described.     

低旁瓣球面共形随机稀疏阵列

针对平面阵列不能实现大范围空域扫描,角度分辨率不高的缺点,对比分析了球面共形阵列的辐射优点,后采用均匀随机排列的方法对球面共形阵列进行稀疏,最终在高角度分辨率和较低成本间实现了很好的性价比折衷,有很大实际意义。