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The effect of amplitude anisotropy of nanoporous alumina films and depolarization of the transmitted radiation on the phase shift between orthogonally polarized components of the transmitted radiation was studied using Stokes-polarimetry and matrix coherence methods. The test samples were illuminated by linearly polarized radiation with the polarization azimuth of 45° in the wavelength range from 400 to 1000 nm. The systematic error introduced into the phase shift between the orthogonally polarized components of the transmitted radiation as a result of neglecting the material amplitude anisotropy and the depolarization of the transmitted radiation was established.

The polarization transformations of light interacting with nanoporous alumina films were investigated theoretically and experimentally. It was shown that a compact device based on nanoporous alumina film could be designed to control light polarization by functioning in various regimes, in particular, as quarter-wave and half-wave plates. It was established that the regimes could be switched from one to another by varying the film orientation relative to the incident light beam. It was found that quasi-circularly polarized light beams with a wide angular spectrum could be formed in a broad spectral region by using the nanoporous alumina film.

The results of an investigation of the metrological characteristics of a standard, which can store, reproduce and transfer the unit of average power from 0.1 mW to 5 mW in the 0.6–1.7 μm spectral range with a relative expanded uncertainty not exceeding 0.002, and an attenuation from 0.05 dB to 60.00 dB, with an expanded uncertainty of less than 0.2 dB, are presented.

Stokes parameters were measured for radiation reflected in the range 5° to 80° by silver-colored, white, and black thermal control coatings deposited on an aluminum alloy substrate, by green paint on a phenolic plastic surface, and by uncoated carbon-fiber reinforced plastic illuminated by linearly polarized He–Ne laser radiation at an incident angle of –5°. The bidirectional reflectance distribution function of the investigated samples was determined as a function of the view zenith angle.

We have investigated the change in the degree of polarization of radiation reflected in the mirror direction by thermoregulating coatings (white, black, and silver paints) sprayed on aluminum, as well as by polymeric composite materials (phenol plastic painted green and bare carbon-filled plastic) illuminated at various angles by linearly polarized radiation from a He-Ne laser. Angular dependences of the bidirectional regular reflectance of the surface of the investigated materials taking into account only the polarized component of reflected radiation have been obtained.

Laser (λ = 0.63 μm) Mueller polarimetry at different angles of incidence and detection is used to measure the elements of the Mueller matrices of polystyrene films, as well as of polystyrene films modified by adding carbon nanoparticles (fullerenes or nanotubes). The complex index of refraction, depolarization index, and polarizance (degree of polarization) of the test samples are determined. It is shown that adding even a small amount (1.0–3.5 mass %) of fullerenes or carbon nanotubes changes the depolarization properties of the modified polystyrene films. Depending on the illumination and observational geometry, these films are found to have different depolarization properties.

It is shown that the representation of the coherence matrix (the polarization density matrix) of beams of electromagnetic waves as a biquaternion corresponding to the four-vector of a pseudo-Euclidean space whose components are the intensity and the Stokes parameters provides a possibility of introducing the group transformations of these quantities isomorphic to SO(3.1) group. These transformations are a subset of the set of Mueller polarization matrices which, generally speaking, form a semigroup. The reduction of the semigroup of Mueller matrices to the group of transformations opens the possibility to use the vector parameterization of SO(3.1) group for interpretation of the polar decomposition of Mueller matrices. In particular, in this approach, the elements of the Mueller matrices corresponding to phase elements and polarizers turn out to be most simply and naturally related to their eigenpolarizations.

The ability of a polymeric polyvinyl alcohol film modified by TiO2 or silver nanoparticles to scatter, reflect and transmit incident polarized radiation and to form an illumination background close to diffuse scattering with the minimal power losses were studied.

We have used laser Stokes polarimetry to study changes in the structure of paper for offset printing when exposed to a high-frequency electromagnetic field. We have shown that the effect of a high-frequency electromagnetic field on paper appears as a decrease in the structural ordering of the material and a change in the shape of the indicatrix of the reflected radiation power from an He-Ne laser at the wavelength 632.8 nm, a decrease in the bidirectional reflection and transmission coefficients of the paper. We have established that when the force lines of the magnetic component of the high-frequency electromagnetic field are oriented perpendicular to the plane of the sheet of paper, we observe a more substantial decrease in the anisotropy in the surface layer and within the interior (the volume) of the paper than when the lines of force are oriented parallel to the plane of the paper.

The kinetics of formation of an oxide film on the surface of the cathode of an atmospheric-pressure glow discharge in helium has been investigated by the method of laser reflectometry. It has been established that the film is formed at a cathode temperature exceeding 550 K, and in 200 sec from the time of discharge initiation at a current of 1 A it becomes thicker than 1 μm. The film consists of several concentric zones. For each of these zones, a change in time of the directional hemispherical coefficient of reflection at a wavelength of 0.63 μm was determined. It is shown that the formation of an oxide film on the cathode surface leads to an increase in the cathode drop.

A description is given of a goniophotometric polarimeter for determining the Mueller matrices of the optical properties of objects. The physical sense of the elements of Mueller matrices is demonstrated and formulas are introduced for calculating them utilizing the measured components of a Fourier expansion of a recorded signal for four and six positions of the first phase plate.

We have measured the Stokes parameters of the He–Ne laser radiation (λ = 0.63 μm) reflected at angles of incidence from 5 to 70° by glass‐reinforced plastic based on a silicon‐organic polymer binder before and after its heating to 1200 K by CO2 laser radiation. The probe radiation from the He–Ne laser is linearly polarized parallel or perpendicular to the incidence plane. It is shown that the flux reflected in the mirror direction by samples illuminated at a Brewster angle (θ ∼ 56°) by He–Ne laser radiation linearly polarized in the plane of incidence contains a component with elliptical polarization.

It is shown that the widest differences in the values and angular distributions of the polarization characteristics of the radiation reflected from the leaves of different kinds of plants are observed when a leaf is illuminated at an angle of 55° by He–Ne laser radiation (λ = 0.63 μm) linearly polarized in the plane of incidence. It has been found that the radiation reflected from a leaf becomes elliptically polarized at observation angles of 55° ± 10°. The ellipticity of the radiation reflected from a leaf depends on the thickness of the leaf plate and the position of the top or undersurface of the leaf relative to the direction of illumination.

Results of laboratory simulation experiments on the influence of H2SO4 solutions on the optical characteristics of the radiation reflected from Rhododendron smirnovii leaves illuminated at an angle of 55° by He–Ne laser radiation (λ = 0.63 μm) linearly polarized in the plane of incidence are presented. The coefficients of correlation between the optical characteristics of the reflected radiation, the concentration of the acid, and the pigment composition of the leaves have been calculated. It is shown that the influence of acidic stresses on the polarization characteristics of the radiation reflected from a leaf manifests itself indirectly as changes in the concentration of chlorophyll a and chlorophyll b and changes in their ratio in the leaf when observation is performed at angles of 50–60°.

Using the method of mathematical modeling, we consider the transformation of a random error of light intensity measurement into an error of determining elements of the light scattering matrix. We consider a device in which the polarization properties of probing radiation change depending on the setting of the phase plate and polarization analysis of scattered radiation is performed while the second phase plate located ahead of a stationary analyzer is rotated. A set of settings of the first phase plate has been revealed, which provides a minimum random error in determining the scattered light matrix elements.

For a Stokes polarimeter with a rotating phase plate, formulas were obtained for calculating the polarization characteristics and their systematic errors caused by the departure of the anisotropy parameters of the optical elements used from ideal ones and also by the deflection of the initial position of the phase plate "fast" axis from the analyzer transmission axis. The manifestation of the mentioned factors in the systematic errors of determining the polarization characteristics of radiation of different forms of polarization is considered. The results of model calculations have been confirmed by experimental data.

An automated Stokes-polarimeter with a rotating phase plate has been developed to measure the polarization characteristics of radiation reflected and scattered by objects at different angles to the surface. An estimate is made of the systematic error due to variation of the initial position of the fast axis of the phase plate and deviation of the phase difference of the λ/4 plate from 90°.

An automated Stokes polarimeter of the dynamic type is created to measure the polarization characteristics of radiation emitted, reflected, and scattered by objects at different angles to a surface. An analysis of the versions of processing of measurement resuls has shown that the dependence of a random error in determination of the parameters on the number of positions N of a quarter-wave plate, at which the radiation intensity is measured, is of a similar nature as the dependence on the number of independent measurements of the same quantity $$( \sim 1/\sqrt N )$$ .

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.

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.

An experimental system is described which is intended for measurements of reflection coefficients at wavelengths of 0.63; 1.15; 3.39, and 10.6 μm and of the thermodynamic temperature of the surface of materials heated in air or in an inert atmosphere at pressures from 1.3·102 to 1.3·105 Pa. An analysis of the errors in reflection coefficient and temperature measurements is made.

The polarization degree, rotation of the polarization plane, and strength indicatrix of radiation with a wavelength of 0.63 μreflected from the surface of a unidirectional superhigh-modular organic plastic are investigated.

At the wavelength 0.63 μm the degree of polarization, the angle of rotation of the polarization plane, and the indicatrix of the intensity of radiation reflected by the surface of composite materials before and after their heating by radiation of a CO2 laser were measured.

It was demonstrated that presentation of the coherent matrix (polarization density matrix) of the electromagnetic beams as biquaternion corresponding to the four‐vector of the pseudo Euclidean space with intensity and Stokes parameters as components gives the possibility for introducing of the group transformations of such values isomorphic to the S(3.1) group. These transformations are the subset of the set of polarization Mueller matrices creating algebraic structure of semigroup. Reduction of the semigroup of Mueller matrices to the group of transformations make it possible to use the vector parameterization of transformations of the group SO(3.1) for interpretation of polar decomposition of the Mueller matrices. In this approach in particular the elements of Mueller matrices corresponding to retarders and polarizers are more simple and natural connected with there eigenpolarizations.

Regularities of changing of polarization characteristics of He-Ne laser radiation reflected and transmitted by inhomogeneous media illuminated with super Gaussian or Bessel beams are investigated. As the inhomogeneous media the (35 ± 5) μm thickness "cigarette" paper has been chosen.© (2008) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

In this work the abilities of a polymeric polyvinyl alcohol (PVA) films modified by ultradisperse silver nanoparticles to polarized incident radiation and to form an illumination background close to diffuse scattering with the minimal power losses were studied.

By means of goniophotometric Stokes polarimeter angular distribution of polarization characteristics of He-Ne laser radiation reflected by polyvinyl alcohol (PVA) films modified with SiO 2 nanosol was investigated. Increasing of nanosol content in PVA films caused increasing of intensity of diffuse component and decreasing of polarization degree of radiation reflected at the angles from 20° to 60-70°.

The electron beam irradiation effect on optical characteristics of polystyrene films modified by carbon nanoparticles is investigated. It was found that reflectance and transmittance of films modified by nanotubes, are in some times less, than corresponding reflectance and transmittance of polystyrene films without additives or films, modified by C 60 . The electron irradiation of samples modified by nanoparticles results to the decreasing of depolarization degree of laser radiation reflected and transmitted by investigated films.

A paper for offset printing was exposed to radio frequency discharge plasma and radio frequency electromagnetic field. Optical response and structural features of paper before and after the treatment have been investigated by several techniques: digital laser speckle photography, laser Stokes polarimetry and attenuated total reflectance (ATR). The changes of statistical distributions of speckle patterns has been observed for plasma treated paper as a result of increase of correlative dimensions of structural heterogeneity of modified paper. It is shown also that the radio wave treatment leads to anisotropy reduction in the paper structure that is more apparent if the magnetic field lines are oriented transversely to the plane of a paper sheet.

In the spectral regions 0.63 and 1.15 μm, measurements are made of the degree of polarization and indicatrix of radiation reflected from the surface of composite materials before and after their heating in air by radiation from a CO2 laser.

where C I = 1.191.I0 -16 V.m 2 and C 2 = 1.4388.10 -2 ~ pyrometric constants, L I and L 2 are the spectral densities at the wavelengths kz and ~2, and R12 is the relative coefficient of reflection for radiation in the two spectral regions with the wavelengths ~i and ~2. In (i) reflected radiation is characterized by the ratio of the directional-hemispherical albedos R12 = pi(80, ~0:2~)/P2(80,~ 0:2~) for ~i and ~2, respectively. However, it is typically more convenient to use the ratio of the bidirectional (directional-directional) albedos for a mirror reflection pi(80, ~0: 8r,~ r)/P2(80, ~0: 8r,~r) (Sr = 8o and~r = ~0 + ~). One can relate these two ratios by using the equivalent solid angle [2]

To evaluate the efficiency of energy delivered by laser irradiation it is necessary to have information about the behavior of the reflection coefficient of the material during the irradiation process. The change in the reflective properties of the material both directly and through surface processes is linked with the temperature in the laser heating zone. To determine by optical methods the true temperature of the heated surface it is necessary to have information about the spectral density of the energy brightness L~, and the thermal emissivity s%, which for nontransparent bodies is related to the reflectiVity by the relation e% = I--R%. The use of a photometric sphere [i] permits determining the reflection coefficient of the material at the wavelength of the C02 laser radiation used for irradiation and simultaneously performing measurements on the probing radiation reflected from the sample in the other spectral region used for pyrometry.

The reflection coefficients at the wavelengths 0.63, 1.15, and 10.6 μm of composite materials, heated in air by continuous CO2 laser radiation, were determined experimentally.