Complex degree of mutual anisotropy of extracellular matrix of biological tissues

We study the possibility of the differentiation of optical anisotropy properties of biological tissues in different physiological states by means of statistical analysis of coordinate distributions of a new analytical parameter, the complex degree of mutual anisotropy of a network of birefringent filament-like protein crystals.     

Complex degree of mutual anisotropy of linear birefringence and optical activity of biological tissues in diagnostics of prostate cancer

We present theoretical fundamentals of polarization and correlation analysis of the optical anisotropy of biological tissues. Results of measurements of coordinate distributions of the complex degree of mutual anisotropy (CDMA) that are formed by birefringent structures of the prostate tissue with benign and malignant changes are compared. Magnitudes and ranges of variation of statistical (the firstto fourth-order distribution moments) and correlation (excess of autocorrelation functions) parameters of the coordinate CDMA distributions of histological sections of the prostate postoperative bioptic material are studied. Objective criteria of the diagnostics of the appearance of pathology and of the differentiation of the degree of its severity are determined.     

Impact of polarization dependent loss on degree of polarization as feedback signal of polarization mode dispersion

Polarization dependent loss (PDL) has been recognized as a critical issue because various inline optical components may have nonnegligible PDL effect that interacts with polarization mode dispersion (PMD).We investigated the impact of PMD-PDL interaction on degree of polarization (DOP), which is the most commonly used feedback signal in PMD compensation. The simulation results of a 40-Gb/s NRZ code optical transmission system show that the maximum PMD increases from approximately 40 ps to more than 45 ps, while minimum DOP declines from approximately 0.6 to approximately 0.2. The interaction of PMD and PDL also induces residual PMD underestimation of 5-8 ps, which causes degradation of PMD compensation performance.     

起偏角对保偏光纤中光波偏振度的影响

实际应用中,入射到保偏光纤的光波通常是准单色光。当入射光的偏振方向与保偏光纤本征轴未对准时,光波在保偏光纤中传播时的偏振度会发生变化。利用部分相干理论分析了准单色偏振光和部分偏振光在保偏光纤中传播时偏振度随起偏角和传播距离的变化情况。实验研究了部分偏振光的偏振度随起偏角变化的规律。研究结果表明:传播距离在厘米量级内时,偏振度随传播距离的变化较明显,对于一般的长距离传输而言,传播距离对偏振度的影响可以忽略;与传播距离相比,起偏角对偏振度的影响较大,为了使偏振度的相对变化量小于0.01%,起偏角必须控制在0.405°以内。     

On the measurement of the generalized degree of polarization

On the basis of well-known methods to obtain the standard Stokes parameters, two simple experimental procedures are analysed to measure the so-called generalized degree of polarization, P, defined elsewhere [Opt. Commun., 149 (1998) 230]. After discussing the accuracy of the methods, the generalized degree of polarization of a non-uniformly polarized beam emerging from an optically pumped birefringent Nd:YAG rod optically pumped is experimentally investigated in terms of the pumped power.     

Entropy and degree of polarization for nonlinear optical waves

I show that the usual definitions of entropy and degree of polarization are not relevant for nonlinear optical waves, because they would lead to the erroneous conclusion that a genuine process of reversible propagation would be characterized by an irreversible process of entropy production. To circumvent this problem, I propose appropriate definitions of entropy and degree of polarization that depend on all the statistical moments of the nonlinear wave, so that they exhibit the satisfactory property to be conserved during a reversible propagation process.     

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     

Definitions of the degree of polarization of a light beam

A necessary and sufficient condition is derived for certain ad hoc expressions that are frequently used in the literature to represent correctly the degree of polarization of a light beam.     

Linear polarization degree for detecting magnetic properties of small particles

Motivated by the recent advances with magnetic nanoparticles, in this research we propose a new technique for their characterization based on the measurement of certain polarimetric parameters of the scattered light, such as the linear polarization degree when it is determined at a "right-angle" scattering configuration. We will show the sensitivity of its spectral evolution with the magnetic properties of the particle.     

Spatial correlations and degree of polarization in homogeneous electromagnetic fields

We consider stationary electromagnetic fields modeled as superpositions of unpolarized and angularly uncorrelated plane waves and show that in anisotropic case the electric cross-spectral tensor is proportional to the imaginary part of the Green tensor. This is as for blackbody radiation, but here the field need not be in thermal equilibrium. We also evaluate the degree of polarization for a homogeneous but nonisotropic field for which the plane waves propagate within a cone of angles. The results are compared with the known polarization properties of blackbody radiation.     

Theoretical study of mutual control mechanism between magnetization and polarization in multiferroic materials

The mutual control mechanism between magnetization and polarization in multiferroic materials is studied. The system contains a ferromagnetic sublattice and a ferroelectric sublattice. To describe the magneto–electric coupling, we propose a linear coupling Hamiltonian between ferromagnetism and ferroelectricity without microscopic derivation. This coupling enables one to retrieve the hysteresis loops measured experimentally. The thermodynamic properties of the system are calculated, such as the temperature dependences of the magnetization, polarization, internal energy and free energy.The ferromagnetic and ferroelectric hysteresis loops driven by either a magnetic or an electric field are calculated, and the magnetic spin and pseudo-spin are always flipped synchronously under the external magnetic and electric field. Our theoretical results are in agreement with the experiments.     

Turbulence-induced changes in degree of polarization, degree of coherence and spectrum of partially coherent electromagnetic beams

Based on a recently formulated unified theory of coherence and polarization, a method is described to study turbulence-induced changes in the polarization, the coherence and the spectrum of partially coherent electromagnetic beams on propagation. The electromagnetic Gaussian Schell-model beam is taken as a typical example of partially coherent electromagnetic beams, and the closed-form expressions for the degree of polarization, the degree of coherence and the spectrum of electromagnetic Gaussian Schell-model beams propagating through atmospheric turbulence are derived in the quadratic approximation of Rytov's phase structure function. Some interesting results are obtained, which are illustrated by numerical examples and are explained in physics.     

Quantum measurement of the degree of polarization of a light beam

We demonstrate a coherent quantum measurement for the determination of the degree of polarization (DOP). This method allows us to measure the DOP in the presence of fast polarization state fluctuations, difficult to achieve with the typically used polarimetric technique. A good precision of the DOP measurements is obtained using eight type II nonlinear crystals assembled for spatial walk-off compensation.     

Model description of the degree of polarization of nonstationary light waves

A theoretical approach is developed that provides the possibility of representing partially polarized radiation in the form of a sum of mutually orthogonal polarized and incoherent components and in the form of a model device with a time-dependent circular birefringence. This approach allows one to apply the vectormatrix Jones method in calculations. The possibility of theoretically determining the degree of polarization of the light passed through a corresponding device placed in an external magnetic field is shown as an illustration.     

Stokes parameters and degree of polarization of nonparaxial stochastic electromagnetic beams

On the basis of angular spectrum representation and the stationary-phase method, far-field expressions for generalized Stokes parameters of nonparaxial stochastic electromagnetic beams are derived, which permits us to study the changes in the ordinary Stokes parameters upon propagation, and the changes in the spectral degree of polarization of partially polarized nonparaxial stochastic electromagnetic beams. It is shown that the spectral degree of polarization changes across the section on beam propagation.     

Study of fiber-optic current sensing based on degree of polarization measurement

A novel fiber-optic current sensing scheme is proposed by converting the Faraday rotation to the optical signal's degree of polarization (DOP) change. In this scheme, the lightwave passes through a fiber resonant cavity multiply and experiences Faraday rotation simultaneously. Its main merit is immunity from the environment disturbance to the fiber used in ordinary Faraday rotation sensor. Brief theoretical analysis and simulation are given to show its basic characteristics. Experimental results are demonstrated and the feasibility of the proposed method is also shown.     

利用偏振度研究混合目标的混合比

提出一种利用偏振度研究混合目标混合比的新方法。通过建立混合目标模型将混合目标散射光的偏振度与混合目标的混合比建立直接的关系,在理论上得到了混合目标混合比分别与混合目标偏振度和归一化偏振度之间的数值关系,并且进一步给出了混合目标混合比由归一化偏振度的反演结果,为研究混合目标提供了新的思路与方法,对偏振度探测混合目标的实验以及工程应用都有重要的理论意义。     

Intensity fluctuations and degree of polarization in three-dimensional thermal light fields

The normalized intensity fluctuations of arbitrary electromagnetic wave fields obeying Gaussian statistics are expressed in terms of the three-dimensional degree of polarization. This general formulation implies an important physical result concerning the polarization of planar fields and the dimensionality of the formalism. The results are expected to be particularly useful in intensity interferometry.