The scattering of partially polarized light by oriented atoms

A compact expression is derived for the cross section of scattering of arbitrarily polarized light by oriented atomic systems, in which the dependence on the geometric parameters and on the Stokes parameters preassigning the state of partial polarization of incident radiation is explicitly separated. It is found that the cross section of any photoprocess accompanied by photon absorption (stimulated emission) contains the sum of the products of the circular and linear dichroisms of the process by the respective Stokes parameters. The effect of the atomic orientation and of the dissipation of light energy on the polarization singularities and angular distribution of scattered light is investigated. In particular, it is demonstrated that, in the case of an open dissipation channel, the angular distribution remains dependent on the atomic orientation even in the case of zero degree of circular polarization of scattered radiation.     

Scattering of atoms by light

This review discusses the latest theoretical and experimental achievements in the resonant light pressure acting on the translational motion of atoms. Alongside with the effects due to the spontaneous light pressure (atomic deflection, velocity bunching, cooling), various manifestations of the effects of induced light pressure are considered in detail. This paper provides the theory and experiments of atoms scattering by a standing light wave under the conditions of coherent and non-coherent interaction, diffraction and interference of atomic beams. The problems where atomic motion along two trajectories and Landau-Zener transitions between them are essential, are studied. The kinetic phenomena (scattering, cooling, channeling) due to the motion of the particles exposed to gradient force and also friction and diffusion caused by spontaneous emission are considered. The influence of the recoil effect under spontaneous emission of atoms on non-linear polarization phenomena is discussed.     

Second-order orientation effects in light scattering by polarized atoms

A compact expression is derived for the part of the cross section for light scattering by axisymmetrically polarized atomic systems proportional to the third-rank state multipole. The effect of the second-order orientation determined by this state multipole on the polarization and angular distribution of the scattered light is studied. The polarization of the incident light can be arbitrary and is specified by the Stokes parameters. A number of orientation effects in the scattering process are shown to be induced precisely by the second-order orientation. In particular, when nonpolarized light is scattered by an oriented atom, the scattering intensity in the perpendicular direction depends on the second-order orientation alone. The second-order orientation also preserves circular dichroism in the linear polarization of the forward-and back-scattered light.     

Analysis of distribution of partially polarized light

A new method for characterization of the distribution of the partially polarized light is described. Analysis of distribution is based on three dimensional radial distribution function. The radial distribution function is useful method of determining type of the distribution of partially polarized light. For uniformity analysis of the distribution method which is based on calculation of the correlation coefficient is presented.     

随机取向双层椭球粒子偏振散射特性研究

基于T矩阵方法,给出了随机取向、轴对称、含核椭球粒子的散射计算方法.散射体的核和外壳均可为非球形粒子,整个粒子具有轴对称性.以含核椭球粒子为模型,计算了含有吸收性内核(黑炭,black carbon)的水凝物气溶胶的散射特性,分析了核的大小、形状对消光系数、散射系数、吸收系数、不对称因子、单次散射反照率以及Muller矩阵等的影响. 关键词： 光散射 T矩阵 Muller矩阵 椭球粒子     

Manifestation of the second-order alignment in light scattering by polarized atoms

An expression for the cross section of light scattering by axisymmetrically aligned atomic systems is derived in a compact form. The cross section under consideration is proportional to the state multipole of the fourth rank. The effect of the second-order alignment determined by the fourth-rank state multipole on the polarization and the angular distribution of scattered light is investigated. The polarization of incident light can be arbitrary and, in the general case, is specified by the Stokes parameters. In particular, it is demonstrated that the second-order alignment cannot induce circular polarization of scattered light and does not influence the dissipation-induced effects of circular dichroism associated with the first-order alignment but leads to a change in the angular distribution and the degree of linear polarization of the scattered light.     

Scattering of polarized electrons on oriented light nuclei

For a series of parameter values characterizing an axially symmetric nuclear orientation, the differential cross sections of electrical excitation of oriented⁷Li,¹⁰B nuclei by completely polarized ultrarelativistic electrons with nuclear transition to the first excited states are calculated as a function of the transmitted momentum q. The nucleus is described by a multiparticle oscillator shell model in intermediate coupling. The contribution to the cross section due to nuclear polarization is calculated; it is compared with the influence of the alignment of the nuclei. It is shown that the cross sections calculated for these two cases may differ significantly, both in magnitude and in the character of the dependence on q. For a series of transitions to low-lying levels of the⁷Li,¹⁰B nuclei, systems of equations in terms of reduced nuclear matrix elements of multipole transitions and statistical solutions are obtained; their solution, with cross sections measured in different kinematic conditions but for fixed q as parameters, allows not only the absolute values of the desired quantities to be established, but also the relative phases of the reduced matrix elements.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 5, pp. 84–88, May, 1990.     

Scattering of light exotic atoms in excited states

The differential and total cross-sections for the scattering of muonic, pionic, kaonic and antiprotonic hydrogen in excited states from atomic hydrogen have been calculated for the purpose of atomic cascade calculations. The scattering problem is treated in a fully quantum mechanical framework which takes the energy shifts and, in the case of the hadronic atoms, the widths of the ns states into account. The validity of semiclassical approximations is critically examined. Received 4 December 2001 and Received in final form 4 February 2002     

Self-rotation of elliptically polarized light in Doppler-broadened rubidium atoms

We present a theoretical and experimental study of self-rotation of incident elliptically polarized light on a rubidium atomic vapor. We construct density matrix equations, which are then solved numerically, and further averaged over atomic transit times and a Maxwell-Boltzmann velocity distribution. We calculate the rotation angle as a function of detuning for various laser intensities and polarizations. We compare the calculated results with experimental results and find good agreement between them.     

部分偏振高斯－谢尔模光束在准直和失调光学系统中的传输

利用张量方法导出了部分偏振高斯－谢尔模光束在准直和失调光学系统中的相干－偏振矩阵的传输公式，并以经过失调薄透镜为例，详细讨论了部分偏振GSM光束的传输特性。导出的公式提供了一个研究部分偏振GSM光束在准直和失调光学系统中传输的简便方法。     

Testing polarization instruments by measurement of the entropy of partially polarized light waves

The entropy of partially polarized light waves is used to define the accuracy of polarization measurements. A test procedure based upon this method is developed and applied to an example of the investigation of an instrument for the measurement of any light polarization state within 1 ms.     

Scattering properties of an individual metallic nano-spheroid by the incident polarized light wave

The scattering properties of a metallic nano-spheroid under the illumination of different polarized light waves are investigated using 3D boundary element method. The influences of different geometrical sizes of the nano-spheroid and incident directions of the illuminating light wave on the scattering spectrum are studied for different incident polarized light waves. The results show that the metallic nano-spheroid has two intrinsic resonant modes, corresponding to different polarization states and resonant wavelengths. The scattering enhancement, the resonant wavelength, and the location of the enhanced optical field are strongly dependent on the polarization properties of the illuminating light waves, and they can be modulated by appropriately choosing the polarization directions of the incident light wave.     

Scattering of on-axis polarized Gaussian light beam by spheroidal water coating aerosol particle

Small particle light scattering can produce light with polarization characteristics different from those of the incident beam. An analytical solution to the scattering by a spheroid with inclusion for an on-axis polarized Gaussian beam incidence is provided within the generalized Lorenz-Mie theory framework. The shapes of the inclusion can be spherical, confocal spheroid, or non-confocal spheroid. The Muller scattering matrix elements are computed for plane wave incidence or Gaussian light beam incidence. The effect of the size and shape of the inclusion or the coating on the polarized Oaussian light scattering characteristics by a spheroidal water coating aerosol Darticle are commlted and a,nalvzed.     

Scattering of electrons by atoms

The theoretical procedures of current interest in the calculation of electron atom scattering are discussed with emphasis on the intermediate energy range. The essential features of the mathematical methods are described. Some specific results are compared with experiment to illustrate the accomplishments and the limitations of the theory.     

Propagating a partially coherent radially polarized beam through aligned and misaligned ABCD optical systems

In the present work the propagation of a partially coherent radially polarized beam through aligned and misaligned ABCD optical systems is discussed. The elements of the beam coherence-polarization matrix for a partially coherent radially polarized beam propagating through these systems are derived for the first time. Using the derived analytical results the intensity distribution of the focused partially coherent radially polarized beam after a low-NA lens is investigated. It is shown that the coherence of the light source affects the beam intensity profile at the focal plane significantly, while for the given coherence of the light source the focal length of the used lens does not affect the beam intensity profile at the focal plane. This is consistent with the case of a partially coherent Hermite-Gaussian beam, as expected.     

部分偏振光通过透镜时的偏振像差分析

本文定量推导了轴上物点发出的部分偏振光通过透镜时其偏振度、偏振分量方位角和椭率角与透镜参数和入射光参量间的关系。对已知参数的透镜进行了定量计算，表明处于一定偏振状态的部分偏振光经透镜后其偏振度、偏振分量方位角和椭率角在出射光束截面上呈一定分布，产生偏振像差。给出了部分偏振光基本参量变化的数量级。指出在高精度光学测量中为避免透镜偏振像差影响，应尽可能减小光束半径和发散角。