基于调制偏振光的空间正交方位信息传递系统

介绍了一种基于调制偏振光的空间正交方位信息传递系统。系统利用调制和解调传递一个正交方位,用电光晶体对偏振光进行调制,电光晶体的感生主轴方向构成发射部分的基准方位。接收部分利用Wollaston棱镜和光电转换器进行解调,由感生主轴构成的基准方位和Wollaston棱镜的两正交光轴之间的夹角信息反映了正交方位传递的精确性。     

利用原始光强信号实现空间方位失调角高精度传递新方法

现有基于正弦波磁光调制偏振光的方位失调角传递方法存在精度不高的问题,提出了一种利用原始光强信号中极值点信息实现方位失调角高精度传递的新方法。建立了基于任意位置光强信号求解初始光强的模型,推导了大角度范围内粗略失调角的计算公式并给出了实现方案,提出了在小角度范围内比现有方法近似精度更高的获取失调角信息的方法。仿真结果以及误差分析表明：利用该方法得出的方位失调角传递误差远远小于现有方法,为实现空间方位失调角高精度传递提供了一种参考。     

基于磁光调制偏振光的空间方位失调角高精度测量新方法

调制偏振光可以作为方位信息的载体,实现方位角度信息的传递,在军事、航天和生物医药等领域有广泛的应用前景.阐述了基于磁光调制偏振光的方位失调角测量原理,分析了现有测量原理中的误差来源.为了从理论方法上提高测量精度,提出了直接计算的方法,将磁光调制后的光强信号直接进行取极值点处理,建立了失调角与极值点之间的方程,详细分析了...     

方波磁光调制测量在无机械连接的设备间方位传递中的应用

在航天、军事等领域往往需要传递无机械连接的设备之间的空间方位信息,而传统的方位测量系统测量范围小、测量精度低,难以满足系统高精度大范围传递的要求,为此改变传统方法中的调制方式,将方波磁光调制引入了方位测量系统,建立了基于方波磁光调制的方位测量模型。根据马吕斯定律,建立了方波磁光调制后的输出信号模型,并分析了调制后信号的特点。根据调制后信号的表达式与方位角的关系,推导、建立了调制后信号与方位角之间的关系方程,并利用调制后信号的增减性去除了方程的增根,结合调制前后信号的相位对比扩大了方位角的测量范围,最终得到了基于方波磁光调制的方位测量模型,实现了无机械连接的设备之间方位信息的传递。仿真结果表明,提出的基于方波调制的测量方法与传统方法比较,理论测量精度更高、测量范围更广,这为实现空间方位角高精度大范围测量提供了一种参考。     

贝赛尔函数展开对空间方位失调角测量误差的影响

调制偏振光可以作为空间方位信息的载体,实现方位角度信息的测量,在军事、航天、生物医药等领域有广泛的应用前景。文章阐述了基于磁光调制偏振光的方位失调角测量原理,针对原理中贝赛尔函数展开带来的失调角测量误差,详细推导了截取不同项数时失调角的计算公式。仿真结果表明:随着贝赛尔函数展开式截取项数的增加,失调角的测量误差越来越小;截取二倍频信号与三倍频信号的测量误差相当,但符号相反;截取项数高于四倍频信号后,误差基本保持不变。因此利用磁光调制偏振光进行方位失调角测量时,贝赛尔函数展开式截取项数不易超过四倍频信号。     

空间正交方位信息传递系统的光学设计和分析

在工程技术的许多领域中,都要求精确传递一个与传递方向垂直的基准方位,或测定两个与同一轴线正交的基准方位之间的夹角,这类系统我们称之为“空间正交方位信息传递系统”。例如,要求地面上相隔一定距离的望远镜对于同一星体或航天目标作同步的追踪;测定位于同一铅垂线上两台经纬仪水平方位的夹角等.偏振旋光仪一类光学仪器,究其实质,也是测定两个基准方位的夹角.实现方位信息传递的方案有多种,其中光学传感器具有精度高、抗干扰能力强、传递距离大等优点,特别是在发射和接收部分之间不可逾越时更具有独特的优越性,本文比较详细地讨论使用扩…     

磁光调制方位传递系统中螺线管近轴区磁场影响分析

磁光调制方位传递系统中,交变电流驱动内置磁光材料的螺线管磁场至关重要,直接关系到方位信息的传递精度。研究了交变电流驱动的螺线管内磁场对方位信息传递精度的影响。首先,利用麦克斯韦方程构建空心螺线管电磁场模型,分析驱动信号频率对磁场的影响;然后结合安培环路定律建立内置磁光材料的螺线管内部磁场模型;最后分析无松弛极化介质、松弛极化介质、驱动信号频率等对系统方位传递精度的影响。结果表明:驱动信号频率是影响系统方位传递精度的重要因素,且方位传递误差存在规律性;无松弛极化介质与松弛极化介质对系统方位传递精度的影响程度相当。该结果为研究磁光调制方位传递系统的方位传递精度与系统优化设计提供了参考。     

天空偏振光时域分布稳定性的实验研究

太阳光在穿过大气层时与大气粒子发生散射作用,形成了稳定的偏振光分布模式,与太阳的位置、观测地点的位置以及不同的大气介质等因素有关。瑞利散射模型描述了偏振光在大气中的分布模式,被广泛的用于研究偏振光与太阳的信息传递关系。本文研究基于瑞利散射模型的天空偏振光时域分布稳定性,设计了一个由偏振图像采集系统和方位对准系统组成的实验平台,实现对天空偏振光分布的长时间测量,解算各时刻的太阳方位角和太阳高度角。以天文学年历计算值为基准,得到太阳方位角误差1.34°(1σ)和太阳高度角误差-2.28°(1σ)作为稳定性参数,结果表明天空偏振光时域分布具有较强的稳定性。本实验拓展学生对天空偏振光和大气散射的认识,激发学生兴趣和创新的精神。     

强度调制偏振光谱仪傅里叶变换解调原理研究

针对强度调制新型偏振光谱仪,研究了基于傅里叶变换法实现偏振光谱信息解调的可行性.结合强度调制偏振光谱仪实现偏振光谱信息调制的机理,给出了采用傅里叶变换法实现偏振光谱信息解调过程的完整数学推导,并对解调过程进行了计算机仿真模拟.模拟结果表明:基于傅里叶变换的解调方法可以高保真获取待测光辐射的偏振光谱信息,将该方法应用于强度调制偏振光谱仪偏振光谱信息的解调是可行的.     

量子光通信中偏振光空间姿态传递

通过设计正交偏振光信标器,实现了空间信标姿态的单光路传递,为星地量子光链路的建立提供了条件.通过分析光学器件,尤其是镀膜器件中偏振信标光的传递特性,仿真分析不同入射角、旋转角条件下,出射信标光的偏振模式.分析了由光学器件引入的位相差和不同反射率、透射率对偏振模式的影响.利用琼斯矩阵推导了马吕斯定律在椭圆偏振光入射时的表达形式,建立起测量椭圆偏振光主偏振方位角模型.利用光电位置传感器接收正交信标光,结合光电位置传感器的光点位置检测能力解耦信标光的俯仰角和方位角,利用光电位置传感器的光强探测能力解耦信标光的偏振基矢角,实现了单器件三维信标姿态测量.实验表明,所述系统具有完成信标光三维姿态检测的能力,可用于星地量子光通信、空间信标姿态检测.     

The spatial polarization distribution over the dome of the sky for abnormal irradiance of the atmosphere

The paper deals with the polarized radiative transfer within a slab irradiated by a collimated infinitely wide beam of arbitrary polarized light. The efficiency of the proposed analytical solution lies in the assumption that the complete vectorial radiative transfer solution is the superposition of the most anisotropic and smooth parts, computed separately. The vectorial small-angle modification of the spherical harmonics method is used to evaluate the anisotropic part, and the vectorial discrete ordinates method is used to obtain the smooth one. The azimuthal expansion is used in order to describe the light field spatial distribution for the case of abnormal irradiance and to obtain some known neutral points in the sky especially useful for polarized remote sensing of the atmosphere.     

Simple parametric representations of the polarization optical properties of birefringent biological tissues in reflection polarization spectroscopy

The use of polarization reflection spectroscopy for investigating complex scattering media, including orientationally ordered optically anisotropic elements, requires a special choice of output parameters (represented by spectra) that characterize polarized light scattering by objects under study because the standard characteristics, such as the Mueller matrices, depend on the azimuthal orientation of the medium. We propose compact and convenient sets of experimentally determined output parameters that involve separate detection of co- and cross-polarized components of light scattered by a sample irradiated by a normally incident linearly polarized beam and include characteristics invariant with respect to the azimuthal rotation of the sample.     

Angular momentum of gaussian light beams

Analysis of the orbital angular momentum of paraxial light beams shows that a key role in the formation of this quantity is played by phase relations between longitudinal and transverse radiation fields. When a light beam is circularly polarized or has a helical wave front, the azimuthal component of the Poynting vector and the density of orbital angular momentum prove to be non-zero. In the case of circularly polarized radiation, the azimuthal component of the Poynting vector and the density of the orbital angular momentum can change the sign at different points in the cross section of the light beam, while the total orbital momentum of the beam remains quantized.     

Properties of circularly polarized vortex beams

The properties of circularly polarized vortex beams in cylindrical polarization bases are studied. A circularly polarized vortex beam is decomposed into radial and azimuthal polarization. With the proper combination of vortex charge and the handedness of the circular polarization, a focal field with an extremely strong longitudinal component as well as a flat-topped profile can be obtained. The cylindrical decomposition also sheds light on the connections between orbital angular momentum and the spin of the light beams.     

Effect of polarization on focal depth in high numerical apertures optical systems

The generalized cylindrical vector beam is just a linear combination of radial and azimuthal polarization. For radially polarized light in the focal plane, there are two electric field components, the radial component and z-component whose magnitude increase with the increase of numerical aperture. By contrast, for azimuthally polarized light in the focal plane, there is only one electrical field component in the azimuthal polarization, it is easy to understand the difference between the two polarization effects. In this paper, we demonstrate how this phenomenon can be harnessed to make a properly selected polarization component to achieve high focal depth in high numerical aperture systems. Numerical simulations show that the evolution of the focal shape is very considerable by changing polarization rotation angle of the generalized cylindrical vector beam. And some interesting focal spots and focal split may occur. And if the ratio of radial and azimuthal polarization is set properly by changing the polarization rotation angle, a largest focal depth is achieved. The tunable range of the focal depth is very considerable. The ratio of radial and azimuthal polarization is different in different NA optical system for obtaining the largest focal depth. We will denote a technique of polarization-assisted high focal depth in high numerical aperture systems.     

Bessel beams: Effects of polarization

An approximation to a Bessel beam produced by tightly focusing linearly polarized light is known to produce a smaller central lobe than focusing plane polarized light. This is because the plane polarized wave gives a broad central lobe caused mainly by a parasitic longitudinal field component. It is known that this problem can be overcome by focusing radially polarized light. Here we demonstrate that other polarization distributions based on a linear combination of transverse electric (TE1) and transverse magnetic (TM1) fields can give a beam even narrower than for the radially polarized case. Special cases of this combination are identified, corresponding to the smallest width (TE1), and the maximum peak intensity compared with the side lobes (electric dipole polarization). Axially-symmetric forms can be generated by illumination with elliptically polarized light. A particular case is azimuthal polarization with a phase singularity, which is equivalent to TE1. For a semi-angular aperture of 60°, the TE1 case gives a central lobe width 9% narrower than for radially polarized illumination, while for plane polarized illumination it is 12% wider than the radially polarized case.     

Polarization property of light guide surface with bilayered nanostructure

The surface of a solid plate light guide patterned with nanostructure composed of bilayered dielectric and metallic stripes is capable of partially transmitting only one of two orthogonal polarizations while reflecting most of the other, and therefore performs as a reflective polarizer. The polarization dependent transmittance, polarization efficiency and extinction ratio of both parallel and cross stacking of the bilayered nanostructure have been analyzed for all radial and azimuthal light incident angles. Both configurations have shown overall polarization efficiency above 98% over the visible spectrum, and exhibit an extinction ratio above 1,000 within a specific range of light incident angle. Accompanied by a proper polarization converter and light extraction pattern, the polarized light guide can provide a high efficiency or even a polarizer free illumination optics for an application where a planar illuminator with polarized light is required.     

A high-efficient method for generating radially and azimuthally polarized Bessel beams using biaxial crystals

As was shown previously, in propagation of a circularly polarized Bessel light beam along the optical axes of a biaxial crystal, there takes place the conversion of the order of Bessel function. In this paper, a new result is presented which is obtained by varying the polarization state of an input beam. Namely, a linearly polarized beam can be transformed into a beam with the radial or azimuthal polarization state. At that the order-transformation also occurs. The switching between radial and azimuthal polarization states of the output beam is performed by the proper switching between two orthogonal linear polarization states of the input beam. The efficiency of polarization conversion is high and can be practically full at an appropriate choice of the cone angle of the input beam or crystal length.