Angular distribution and polarization characteristics of radiation reflected by a fibrous superhigh-modulus composite material

The effect of a smooth surface binder film and the orientation of filler fibers of unidirectional superhigh-modulus organoplastic on space-polarization characteristics of He−Ne laser reflected radiation is investigated. B. I. Stepanov Institute of Physics of the National Academy of Sciences of Belarus, 68, F. Skorina Ave., Minsk, 220078, Belarus. Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 65, No. 6, pp. 926–931, November–December, 1998.     

Spectral‐Polarization Contrasts in the Problems of Remote Sensing

The results of the investigation of the angular and spectralpolarization characteristics of 4501080nm radiation reflected from the surfaces of natural (leaves of trees, bark) and artificial (colored smooth surface, fabric) objects are discussed. Based on a study of the contrasts between these characteristics, we have determined the most informative spectralpolarization characteristics and the spectral and angular intervals the use of which in remote optical observations of objects would allow their most effective discrimination.     

聚合物电导率对0-3型压电复合材料极化性能的影响

建立了0-3型压电复合材料的等效电学模型.分析了聚合物电导率对复合材料极化性能的影响，研究了聚苯胺改性0-3型锆钛酸铅/聚偏氟乙烯复合材料极化性能与聚合物电导率之间的关系.理论分析和实验结果均表明，提高聚合物电导率可以提高复合材料的极化性能. 关键词： 压电复合材料 电导率 极化 聚偏氟乙烯     

Influence of laser heating on the optical properties of a superhigh-modulus organoplastic material

The degree and azimuth of polarization and the indicatrix of the intensity of radiation (λ=0.63 μm) reflected by the surface of a monodirectional superhigh-modulus organoplastic material after structural transformations induced in it by CO₂-laser radiation are measured. It is shown that the space-polarization characteristics of the radiation reflected by the organoplastic material charred as a result of laser heating correspond to the parameters of radiation scattered by a nontransparent material with an isotropic surface in the approximation of geometrical optics. B. I. Stepanov Institute of Physics, National Academy of Sciences of Belarus, 68, F. Skorina Ave., Minsk, 220072, Belarus. Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 66, No. 5, pp. 635–639, September–October, 1999.     

Structural polarization properties of vector Gaussian beam in the far field

Based on the vector angular spectrum representation of optical beam and the method of stationary phase, the analytical TE and TM terms of vector Gaussian beam have been presented in the far field. By using the local polarization matrix, the polarization properties of the TE and TM terms in the far field are investigated, and it is found that the degree of their polarization is only determined by the spatial location. When the source is completely polarized, the TE and TM terms are both completely polarized in the far field. When the source is completely unpolarized, the TE and TM terms in the far field are partially polarized. The whole beam is also partially polarized except on the propagating axis. Moreover, the degrees of polarization of TE and TM terms are both larger than that of the whole beam.[第一段]     

光子晶体微腔中高偏振单偶极模的研究

三角晶格排列的光子晶体微腔中的偶极模式是简并的,通过改变其晶格的对称性可以消除模式简并.晶格的整体形变破坏了晶格对称性从而影响光场的分布,同时还改变了电磁场的偏振分布.晶格整体形变使得简并的偶极模式分离成x极和y极偶极模式.通过计算分析发现分离后的模式具有良好的偏振特性,从而为实现单偏振光子晶体激光器提供了一种很好的途径.文中针对光子晶体薄板结构的微腔,主要计算了偶极模中x极偶极模式在不同拉伸时以及不同填充因子情况下的Q值,并分别计算了x关键词： 光子晶体 偶极模 品质因子 偏振度     

The number of least degrees of freedom required for a polarization controller to transform any state of polarization to any other output covering the entire Poincaré sphere

Using two typical types of polarization controller, this paper analyses theoretically and experimentally the fact that it is necessary to adjust at least three instead of two waveplates in order to transform any state of polarization to any other output covering the entire Poincar\'{e} sphere. The experimental results are exactly in accordance with the theory discussed in this paper. It has corrected the conventional and inaccurate point of view that two waveplates of a polarization controller are adequate to complete the transformation of state of polarization.     

光纤偏振模色散对信号偏振度的影响

采用一种简化的线路传输模型，详细讨论了在高速光纤通信系统中，线路偏振模色散（PMD ），尤其是二阶PMD、输入信号偏振态等对信号偏振度（DOP）的影响，并指出以信号DOP做 反馈控制信号适合于一阶PMD优化补偿系统，但在较大二阶PMD的影响下，将增加控制算法的 复杂性，使系统可能陷入局部最优解. 关键词： 信号偏振度 偏振模色散 信号偏振态     

光的相干和偏振的相关研究进展

相干和偏振是统计光学体系中紧密联系的两个方面,对激光的传输性质有重要的影响。介绍了相干偏振的基本理论,尤其是以交叉谱密度矩阵为基础的相干和偏振的统一理论。分析介绍了当前该领域的研究热点:偏振特性的传输变化、部分相干光散射理论、谱交叉偏振度(SDCP)和三维随机电磁光束。对相干偏振理论的相关问题进行了总结和展望。     

一种基于新型偏振干涉成像光谱仪的目标偏振信息探测新方法

提出了一种采用基于视场补偿型Savart偏光镜的新型偏振干涉成像光谱仪对二维目标偏振信息进行空间遥感探测的新原理和新方法.在新型偏振干涉成像光谱仪光学系统不变的情况下,通过旋转偏振干涉仪分别测出了三个不同角度下像面上各像点的光强值,反演出了二维面目标的斯托克斯矢量,并给出了各像点偏振度和偏振方向的理论表达式.采用计算机模拟实验对该探测原理和方法进行了验证,所得结果与理论完全符合.从理论和实践上扩展了干涉成像光谱仪的探测功能,与目前国内外所研究的成像光谱仪相比,该成像光谱仪既能同时探测目标二维空间信息和一维光谱信息,又提供了一种获得目标偏振信息的手段和方法.     

Spectral and polarization analysis of optical images by means of acousto-optics

This paper presents results of a theoretical and experimental study of Bragg anisotropic diffraction. The diffraction may be used for filtration of optical radiation and processing of images. Special attention is devoted to the investigation of diffraction, which provides spectral filtration simultaneously with polarization analysis of divergent optical beams. A tunable tellurium dioxide acousto-optical filter for processing of optical images is described in the paper. Some experimental results of the image analysis in visible light and in the near-infrared region of the spectrum are discussed.     

Preparation and properties of GAGG:Ce/glass composite scintillation material

The translucent GGAG:Ce/glass composites are prepared successfully by ball-milling, tableting, and pressureless sintering. The thickness of composites is about 400 μm. The x-ray diffraction(XRD), differential scanning calorimetry(DSC), density of composite materials are measured and discussed systematically. The scanning electron microscopy(SEM) and energy dispersive spectrometer(EDS) elemental mapping are employed to analyze the particle size, the shape of powders, and the distribution of GGAG:Ce particles in the glass matrix, respectively. The decay time, ultraviolet,(UV),x-ray excitation luminescence spectra, and temperature spectra are studied. The results show that the composite materials have high light output, good thermostability, and short decay time. The method adopted in this work is an effective method to reduce the preparation time and cost of the sample. The ultralow afterglow indicates that the composite materials have an opportunity to be used for x-ray detection and imaging.     

Spectral and spectral-polarization characteristics of potato leaves

The results of laboratory investigations of the spectral and spectral-polarization characteristics of radiation reflected from the leaves of potato(Solanum tuberosum) of different varieties are discussed. During the vegetation season of 1997, the angular dependence of the degree and azimuth of polarization of radiation reflected from potato leaves as well as the scattering indicatrices in the range 380–1080 nm were determined by a specially developed method with the use of a laboratory goniometric setup. The relationship between the spectral polarization characteristics of radiation and biological parameters of the potato has been obtained with the help of different methods of statistical analysis and explained on the basis of the known physical mechanisms. Translated from Zhurnal Prikladnoi Spektroskopii. Vol. 67, No. 4, pp. 524–529, July–August, 2000.     

一种光谱偏振成像系统设计及应用

为了获取目标和背景的偏振信息,提高地面目标识别的准确度,提出一种光谱偏振成像探测系统。该系统采用旋转偏振片的方式对入射光的偏振状态进行调制,通过旋转滤光片进行光谱选择,从而实现光谱偏振成像探测。通过对该系统偏振度的探测精度进行实验测试,结果表明,所设计的光谱偏振成像探测系统达到4%的探测精度。利用该系统对地物背景中的迷彩伪装板进行了探测实验,分析所得的偏振度图像发现,目标在背景中较为明显,与草地及土壤背景区域偏振度的差值分别达到0.292和0.283。     

偏振遥感在伪装目标识别上的应用及对抗措施

为了研究偏振遥感对伪装目标的识别特点,分别对不同颜色的伪装网进行了偏振参数测量和成像实验。通过数据分析发现,伪装网的散射偏振度受观测条件和材料自身特性（如反射率、折射率和表面粗糙度）影响很大;伪装涂层对入射光的散射作用可以分为面散射和体散射,其中面散射具有起偏振作用而体散射具有消偏振作用;与自然背景相比,伪装目标的偏振特征非常显著,利用偏振遥感可以有效地识别出常规侦察手段所不能发现的伪装目标。通过偏振遥感的侦察原理和特点分析,提出了可以利用表面结构设计和烟雾等方法对抗偏振遥感的侦察。     

Polarization mode dispersion compensation in a novel dual polarization differential quadrature phase shift keying system

A novel dual polarization differential quadrature phase shift keying (DP-DQPSK) system is proposed, whose receiver is the same as the single polarization DQPSK system, while it does not need polarization de-multiplexing like the conventional polarization division multiplexing QPSK (PDM-QPSK). Polarization mode dispersion (PMD) is mainly considered and PMD compensation for the DP-DQPSK system is studied. As the feedback signal for PMD compensation, the degree of polarization of the signals is discussed in detail. The results show that PMD tolerance can be improved by 89 ps within 1 dB optical signal noise ratio penalty after PMD compensation for the DP-DQPSK system.     

用于光谱基准定标传递技术的传递辐射计研究综述

传递辐射计是实现卫星遥感仪器在轨光谱辐射定标传递的核心设备,也是地面实验室高精度光谱定标系统的关键。介绍了不同机构研制的覆盖350～700, 700～2 500 nm谱段的多个传递辐射计的结构组成、工作原理及辐射定标基准传递方式,及其异同点的比对,再通过它们在不同谱段的定标过程中所应用的关键技术的分析,说明每种技术的优缺点和所能达到的精度,及其应用条件。文中通过对国际上标准计量机构采用的光谱辐亮度基准定标传递过程的介绍,突出了传递辐射计系统的重要作用,再结合其对光谱仪等遥感器定标光源的定标监测应用,说明了传递辐射计在航天辐射定标领域的不可或缺性。最后,通过国内设计的新型传递辐射计的介绍,对传递辐射计未来研究的发展方向和关键问题进行了展望,并对传递辐射计搭配低温辐射计组成的未来实现可溯源国际单位制在轨基准定标传递系统所存在的研究难点予以预测分析。     

Quantitative study of effective parameters of chiral composite material

The effective parameters of chiral composite are studied quantitatively using a model, say, chiral spheres immersed in a nonchiral host medium. The effects of the volume fraction of the chiral phase, f, the parameters of the host medium, and , on the effective properties of the composite are calculated. As an example, the microwave reflection properties of a chiral composite coating is compared with that of its host medium coating.