基于Sagnac原理的单轴分布式光纤传感系统偏振态分析

针对Sagnac干涉型单轴分布式光纤传感器中使用单模光纤作为传感器件时,由于传输光偏振态在双折射影响下所带来的干涉信号“偏振诱导衰落”问题,运用琼斯矩阵分析法,建立了该型传感器系统在传感光纤双折射和外部事件共同作用下,传输光的偏振态对系统功率传输系数影响的数学模型;仿真分析了在传感光纤线性双折射和圆双折射共同作用下,传输光的偏振态对系统功率传输系数的影响;提出了使用法拉第旋转镜提高系统抗偏振能力的改进方法.仿真结果表明,该方法能很好地消除光纤线性双折射和圆双折射.     

Two-dimensional depth-resolved Mueller matrix of biological tissue measured with double-beam polarization-sensitive optical coherence tomography

A double-beam polarization-sensitive system based on optical coherence tomography was built to measure the Mueller matrix of scattering biological tissue with high spatial resolution. The Jones matrix of a sample can be determined with a single scan and subsequently converted into an equivalent nondepolarizing Mueller matrix. As a result, the system can be used to measure the Mueller matrix of an unstable sample, such as soft tissue. The polarization parameters of a porcine tendon, including magnitude and orientation of birefringence and diattenuation, were extracted by decomposition of the measured Mueller matrix.     

用琼斯矩阵法分析别汉棱镜像面偏振态分布

 基于反射定律的矢量式易于追迹复杂系统中光线的三维空间传播方向,计算了别汉棱镜每一面反射光线的方向,利用琼斯矢量法建立每一反射平面的琼斯矩阵以及面与面之间的传输矩阵,得到了一束线偏振平行光通过别汉棱镜后像面上的偏振状态分布,即经由2个屋脊面出射的光束是2个方位角不同的椭圆偏振光,这2个方位角的大小与入射线偏振光的振动方向有关。采用斯托克斯参量测量法,对别汉棱镜像面上偏振状态的分布进行了实验检测,得到了与理论分析一致的结果,指出别汉棱镜的偏振效应将会导致出射光束偏振状态的不均匀分布。     

Analysis of optical compensating schemes of laser Doppler velocimeters

Basic forms of the optical systems of laser Doppler velocimeters with supression of the additive noise component in the output signal are investigated by the Jones matrix method. The expressions for the resulting Doppler signal, taking into account the parameters and orientation of phase elements and the receiving polarization analyser, have been obtained and analysed. Experimental results are given.     

基于Sagnac/双Mach-Zehnder原理的分布式光纤传感系统的偏振态分析

运用琼斯矩阵分析法,建立了该分布式传感器系统在传感光纤双折射和外部事件共同作用下,传输光的偏振态对系统功率传输系数影响的数学模型.仿真分析了在传感光纤线性双折射和圆双折射共同作用下,传输光的偏振态对系统功率传输系数的影响,并提出了利用偏振控制器对输入偏振态进行控制,从而改善干涉信号输出的方法.     

反射式光学电压互感器光路建模及偏振误差分析

光路系统的偏振误差极大地制约着准互易反射式光学电压互感器的准确度.借助琼斯矩阵,建立了分立光学器件及光纤熔接点的传输模型,推导出完整的电压互感器光路系统的数学模型.以此模型为基础,对电压互感器中的偏振误差进行了仿真分析.结果表明:光源偏振度、起偏器消光比及起偏器与相位调制器的对轴角度主要影响系统的检测灵敏度;法拉第准直...     

Use of Dirac matrices in polarization optics

Several matrix methods have been developed for studying polarization properties of light. Jones was the first to apply the matrix method to the study of polarization optics. In Jones matrix formalism the polarized wave field is represented by 2-element column matrix known as Jones Vector and the polarization device encountered by light is represented by a 2×2 matrix, known as the characteristic Jones matrix of the device. Mueller introduced a new matrix method where the wave field is represented by a 4-dimensional vector. The elements of the vector are the Stokes parameters of the beam. In Mueller matrix formalism the optical device is represented by a 4×4 real matrix known as ‘Mueller Matrix’ of the device. The use of coherency matrix also proves to the useful in the study of partially polarized light. Pauli spin matrices have been used to unify the different matrix treatments of polarization optical phenomena. The present article is an attempt to unify the analysis of polarization phenomena using Dirac matrices used by Dirac in quantum mechanics. We have however redefined the set of Dirac matrices in terms of the Kronecher product of Pauli spin matrices.     

基于菌紫质薄膜的相移器及其应用

设计了一种基于菌紫质光致各向异性的相移器,并把它用于相移干涉计量。取向随机分布的极性菌紫质分子对线偏振诱导光的选择性吸收导致分子取向分布不均匀,使其呈现宏观的各向异性,这种各向异性与诱导光的偏振特性密切相关,圆偏振光经过各向异性的菌紫质薄膜后,出射光的偏振特性完全由偏振诱导光决定。基于上述原理设计了一种新型的相移器,用琼斯矩阵法推导了基于相移器的相移干涉原理。该相移器在工作过程中不需要移动Mach-Zender干涉仪内部的任何器件,仅需要改变外部控制光路中诱导光的偏振取向就可以控制参考光的相位,有助于提高设备的抗振能力。用最小二乘法对相移干涉结果进行重建,得到了和实际相位一致的结果,验证了相移器的可行性。     

Optical-fiber-based Mueller optical coherence tomography

An optical-fiber-based multichannel polarization-sensitive Mueller optical coherence tomography (OCT) system was built to acquire the Jones or Mueller matrix of a scattering medium, such as biological tissue. For the first time to our knowledge, fiber-based polarization-sensitive OCT was dynamically calibrated to eliminate the polarization distortion caused by the single-mode optical fiber in the sample arm, thereby overcoming a key technical impediment to the application of optical fibers in this technology. The round-trip Jones matrix of the sampling fiber was acquired from the reflecting surface of the sample for each depth scan (A scan) with our OCT system. A new rigorous algorithm was then used to retrieve the calibrated polarization properties of the sample. This algorithm was validated with experimental data. The skin of a rat was imaged with this fiber-based system.     

Jones phase microscopy of transparent and anisotropic samples

We developed an interferometric microscopy technique, referred to as Jones phase microscopy, capable of extracting the spatially resolved Jones polarization matrix associated with transparent and anisotropic samples. This is a generalization of quantitative phase imaging, which is recovered from one diagonal element of the measured matrix. The principle of the technique is demonstrated with measurements of a liquid crystal spatial light modulator and the potential for live cell imaging with experiments on live neurons in culture.     

静态偏振风成像干涉仪光传输特性和光通量改善

静态偏振风成像干涉仪利用偏振光束来获得干涉图, 光束在偏振元件中的传输特性成为分析研究的关键. Jones矩阵用于分析系统的光学传输特性和偏振态变化过程, 形式简洁,计算方便,容易得出光学元件对系统性能的影响.本文用Jones矩阵对静态偏振风成像干涉仪系统进行了描述, 推导出了适用于普遍情况的系统矩阵表达式,计算出核心偏振元件的偏振化方向和波片方位角对应于系统光通量和干涉调制度的关系,确定了系统中各偏振元件的最佳偏振化方向和波片的最佳方位角; 并通过视场展宽技术和提高四面角锥棱镜的透光率对光通量加以改善,利用光线追迹软件仿真, 对视场展宽前后的干涉强度作了对比,达到预期的效果.为静态偏振干涉成像光谱仪的设计、 研制和工程化提供重要理论和实践指导.     

Statistics of the Jones matrix of fibers affected by polarization mode dispersion

We carry out a statistical characterization of Jones matrix eigenvalues and eigenmodes to gain deeper insight into recently proposed fiber models based on Jones matrix spectral decomposition. A set of linear dynamic equations for the Pauli coordinates of the Jones matrix is established. Using stochastic calculus, we determine the joint distribution of the retardation angle of the eigenmodes and, indirectly, their autocorrelation function. The correlation bandwidth of the eigenmodes is found to be radical2/3 that of the polarization mode dispersion vector. The results agree well with simulations performed with the standard retarded plate model.     

光学电流互感器中线性双折射与法拉第效应的分离检测

分析了线性双折射对光学电流互感器(OCT)电压输出的影响,指出了差除和信号处理方案检测输出光信息的不完备性问题,用琼斯矩阵理论证明了差除和方案不能独立检测块状玻璃传感头中线性双折射的结论。提出了光学电流互感器的椭偏检测方案,从椭圆偏振光参量方程出发,推导了温致线性双折射、法拉第旋转角与输出椭圆偏振光椭率、倾角之间的解析式,证明了椭偏检测法对输出光信息检测的完备性,实现了温致线性双折射和待测电流的同时测量。为保证实时性,提出了输出椭圆光的三态检测方案,采用水平、垂直和45°三个偏振态的实时检偏,既克服了线性双折射的影响又实现了待测电流的实时测量,从检测原理上解决了温致线性双折射对光学电流互感器的影响。     

Causality and the complete positivity of classical polarization maps

Mueller and Jones matrices have been thoroughly studied as mathematical tools to describe the manipulation of the polarization state of classical light. In particular, the most general physical transformation on the polarization state has been represented as an ensemble of Jones matrices, as ∑iV(i)ΦV(i)(?). But this has generally been directly assumed without proof by most authors. In this Letter, we derive this expression from simple physical principles and the matrix theory of positive maps.     

Detection of colorless plastic contaminants hidden in cotton layer using chromatic polarization imaging

A method of chromatic polarization imaging is presented for the online detection of colorless plastic contaminants from ginned cotton in an industrial setting. To understand the experimental results, we consider a realistic microscopic model, including the multiple scattering of anisotropic fibers and the light propagation in anisotropic slabs. A Monte Carlo code, based on the extended Jones matrix, is developed to simulate photon migration with polarization states, and phase information followed. Using simulations and experiments, we analyze the underlying mechanisms and evaluate the performance of this method with different layer thicknesses. Our approaches proposed in this Letter also have the potential to be applied in tissue imaging, remote sensing,and other scenarios.     

光致各向异性记录介质偏振全息图的透射矩阵

在给定参、物光波的偏振态和位相差的关系以后,用光致各向异性介质记录偏振全息图的光学常数分布便被确定。这样,可以把偏振全息图看作是一种复杂的偏振元件,按照偏振元件的矩阵理论,可以求出偏振全息图的透射矩阵。透射矩阵与照明光的琼斯矢量相乘,便可以求出再现光波的琼斯矢量。 关键词：     

单模光纤的磁光效应

本文利用琼斯(Janes)矩阵叙述了单模光纤磁光效应的理论,导出了既具有双折射又具有法拉第效应的琼斯矩阵形式,并利用Mueller矩阵导出电流传感器系统输出光强与法拉第旋转角之间的关系.     

投影光学系统中的偏振像差分析

当光束斜入射时,光学薄膜存在一定的偏振效应。在飞利浦棱镜系统中,当一定大小孔径角的照明光束斜入射到分色合色薄膜后,S偏振分量和P偏振分量存在一定的相位差,使得线偏振光变成椭圆偏振光。利用琼斯矩阵偏振光线追迹的方法,分析了投影光学系统中由于两偏振分量相位差引起的偏振像差,以及它与暗态泄漏光强和系统衬比度的关系。得出了系统出瞳面上的光波偏振特性,以及在不同大小孔径角的照明光束入射下偏振像差的变化。分析了膜厚监控误差对光学系统偏振像差的影响,发现膜厚监控误差对偏振像差和系统衬比度有很大的影响。所使用的分析方法可以应用于其他大口径光学系统。     

Jones matrix for second-order polarization mode dispersion

A Jones matrix is constructed for a fiber that exhibits first- and second-order polarization mode dispersion (PMD). It permits the modeling of pulse transmission for fibers whose PMD vectors have been measured or whose statistics have been determined by established PMD theory. The central portion of our model is a correction to the Bruyère model.     

激光多普勒测速仪中散射光特性的研究

后向散射光特性与多普勒信号的质量密切相关。为了设计高性能的激光多普勒测速仪,运用散斑理论详细分析了激光多普勒信号的强度与散射光斑大小的关系,结合泛函理论给出了计算多普勒电流的散斑表达式,并通过实验的方法研究了回波信号的偏振特性及其强度分布。理论分析与实验结果表明,激光多普勒信号的强度与接收器件光敏面的直径成正比,与光斑的直径成反比;选用光斑较小的圆偏振激光束,并用光敏面尺寸较小的探测器在镜面反射方向上接收信号光,可以大大提高多普勒信号的信噪比,增强系统的探测能力,为提高系统的测量精度创造有利的条件。