The solution of a problem of propagation of the standing and travelling spherical electromagnetic waves in space, free from sources, in case of isotropic medium on assumption of rotational symmetry, is offered by exact solution of the Maxwell uniform equations in spherical coordinates. Analytical expressions for components of fields of the standing and travelling symmetric spherical E- and H-waves and equations of lines of force for different modes are obtained. The graphic pictures of lines of force which reflect the structures of fields of standing spherical E- and H-waves, and dynamics of travelling spherical electromagnetic waves are represented.

Results of a theoretical investigation of the polarization conversion of the electromagnetic wave (EW) in a density- modulated two-dimensional (2D) electron system are presented. A giant enhancement of the polarization conversion efficiency is found to merge under plasma oscillation resonance in the periodic 2D electron system. The cases of the normal and an oblique incidence of the external EW are considered. It is shown that in the total internal reflection regime the total polarization conversion can be reached if the electron scattering in the 2D electron system vanishes. Numerical calculations are performed with the characteristic parameters of an actual 2D electron system in the electron inversion layer on p-Si at the far- infrared frequencies. A solid angle in which the wavevector of the incident EW should reside in order to produce the greatest polarization conversion efficiency is calculated for different aspect fraction values of the periodic 2D electron system.

For the first time we are able to observe the time-resolved Wigner function of enhanced backscatter from a random medium using a novel two-window technique. This technique enables us to directly verify the phase-conjugating properties of random media. An incident divergent beam displays a convergent enhanced backscatter cone. We measure the joint position and momentum (x, p) distributions of the light field as a function of propagation time in the medium. The two-window technique allows us to independently control the resolutions for position and momentum, thereby surpassing the uncertainty limit associated with Fourier transform pairs. By using a low-coherence light source in a heterodyne detection scheme, we observe enhanced backscattering resolved by path length in the random medium, providing information about the evolution of optical coherence as a function of penetration depth in the random medium.

We synthesize a multi-channel phase filter to decompose the light fields into the basis of generalized Gauss-Laguerre modes, (Psi) _nm(r,(phi) ),0<EQn,m<EQN. The filter allows any of nine specified modes to be selected. The contribution of any mode to the image under analysis can be determined from the correlation peak in the focal plane of the corresponding diffraction order. The choice of an optimal radius of the plane and Gaussian illuminating beams is studied. The results on computer simulated selection of desired modes from the laser beams composed of a linear combination of Gauss-Laguerre modes are discussed.

Reciprocity inequalities (uncertainty relations) are studied for a finite light pulse with complex spatio-temporal structure and for statistical ensemble of such pulses. A possibility to create partially coherent pulses (and ensembles) with parameters close to minima of these inequalities both in temporal and spatial domains are discussed. The structure of optimal beams is analyzed from point of view of modal treatment of coherence (biorthogonal Karhunen-Loeve expansion).

Static light scattering by a nano-sized object is studied in detail using a microscopic approach. The nano-object is modeled as an assembly of identical dipole atoms interacting via the electromagnetic field only. The atoms are considered to be linear Lorenz oscillators. Within the microscopic formalism, equations for local field strength are used. The cooperative character of the coherent light scattering by the atomic assembly gives rise to a dramatic modification of the total polarizability. We show the significant role that the geometry and orientation with respect to the external field play in determining the resonance characteristics of nano-object. The relations between the resonance frequency shift and the interatomic distance for some simple geometries are presented.

The problem of diffraction of monochromatic electromagnetic TE- and TM-waves by a 2D (cylindrical) object with inhomogeneous permittivity is reduced to solving the integral Helmotz equations of the second kind (separately for each type of polarization). The integral equations are obtained using Green's theorem, two Helmhotz's equations applied to the inhomogeneous object and homogeneous background, as well as by imposing boundary conditions on the object's surface. Using the finite-elements method the equations are reduced to a set of linear algebraic equations. Computer-aided simulation of diffraction of the plane TE-wave by a homogeneous dielectric cylinder of circular cross-section and the diameter of the wavelength has demonstrated good agreement between the patterns obtained through solving the integral equation and through the rigorous analytical solution as a Bessel series.

It is advanced a two-dimensional model for investigation of spatial dynamics of stationary light fields with disruption of a wave front including optical vortices or with pronounced amplitude inhomogeneity. Theory of synthesis of optical vortices in a Gaussian beam by an optical wedge is developed. Optimum wedge parameters for high efficiency generation of a light beam with perfect optical vortex are found by use of the computer simulation.

In the paper two different approaches for spatial coherence measurement are discussed. The usage of a special optical element (specklegram of shift) in the scheme of Young interferometer essentially raises a relative aperture of the optical device and allows one by an evident way to study the spatial coherence of light and to measure radius of spatial coherence. It is shown with use of the Michelson interferometer, that the consideration of mutual spatial shift of interfering fields allows one to connect directly the spatial distribution of fringe visibility in the area of their localization with the function of a spatial coherence. The theoretical estimations and experimental results for longitudinal distribution of fringe visibility in the area of localization in the Michelson interferometer with an extended source of white light are given.

Modification of photon density of states (DOS) is considered as an essential factor of modified Raman scattering in mesoscopic media with complicate spatial dependence of dielectric function on a scale of incident/scattered photon wavelengths. Possible contribution of redistributed photon DOS over frequency spectrum in mesoscopic metal-dielectric structures to surface enhancement of Raman scattering (SERS) by adsorbed molecules is outlined. Considerable growth of DOS for a certain mode increase spontaneous scattering rate to this mode which in turn promotes stimulated Raman scattering to the same mode. Therefore total effect of DOS on scattering rate can be higher than DOS increase in a given mesoscopic medium versus vacuum.

The transmission and reflection spectra of 1D photonic crystals based on close-packed silver nanosphere monolayers separated by thin solid dielectric films are investigated in the frame of the statistical theory of multiple scattering of waves. In order to realize jointed electron and photonic confinement we choose intermonolayer film thickness so that the photonic band gap and metal nanoparticle surface plasmons are realized at close frequencies in the visible region. Photonic stopband formation is studied under these conditions at different particle sizes, concentrations and geometrical parameters of the system with regard to size dependence of metal nanoparticle dielectric function. The red shift of plasmon resonance with packing factor increasing due to the lateral coupling between close-packed metal nanoparticles within a monolayer is shown. One- dimensional ordering of monolayers gives rise to the formation of the photonic stopband in the vicinity of a plasmon absorbency resonance. The appearance of a doublet structure of attenuation spectra and narrowed reflection peak has been established.

Speckle patterns produced by scattering in random media are sometimes employed as tools for optical measurements and information processing. In those applications of speckles, spatial and temporal correlation properties play sometimes fundamental roles. Therefore, design and control of correlation properties in the scattered fields are an attractive and important subject. From this viewpoint, two types of speckle patterns having extraordinary spatial correlations are reviewed and discussed in this article. The first type of scattered fields is nondiffracting, or propagation-invariant speckles. This type of waves has Bessel-type long tails in transverse intensity correlations and extremely long correlation in the propagation direction. Two schemes for generating nondiffracting speckles by means of an annular aperture and an axicon lens are described. Relations to general nondiffracting beams are also discussed briefly. The second type of waves having long-range correlations is fractal speckles, which have negative power- law intensity correlations in lateral and longitudinal directions. Results of computer simulations are shown for fractal speckles with wide range of a parameter D governing the spatial extent of correlations.

The multifractal description of rough surfaces is discussed and the mechanisms for generation of fractal and multifractal height distributions of inhomogeneities for rough surfaces are simulated. The original technique for estimating the spectrum of singularities is proposed for studying these distributions.

Multilayer fractal structures, being a subclass of nonperiodic yet deterministic media are studied in relation to the problem of classical wave propagation. A general case of fractal multilayers is considered. Numerical calculations reveal that the geometry and optical spectra of such structures are directly connected. Namely, it has been found that structures and spectra exhibit exactly the same scaling relations, which are easily derived from the parameters used in the stack construction procedure. Sharp resonant transmission peaks are found to split when the number of generation of the fractal structure increases, and the number of components in such split multiplets is again directly linked to the stack geometrical features. Treating a multilayer structure as a complex coupled-cavity system yields straightforward physical explanations of the properties found. Likeness of fractal properties to occur in the spectra of fractal multilayers is discussed.

Optical properties of carbon dioxide in the vicinity of its critical point were studied. Amplitude-frequency characteristics of radiation backscattered in CO₂ have been studied using laser Doppler velocimeter based on highly stabilized Nd:YAG³⁺ chip-laser. Significant (up to 10 times) narrowing of backscattered radiation spectrum and increasing of its amplitude (up to 100 times) in the vicinity of critical point were detected and analyzed. Nonlinear temperature dependence of reflection from glass- CO₂ interface was observed. Intrinsic anomaly of light reflection of critical media was revealed. Transmission spectrum of cell with critical CO₂ was measured in 0.35- 1 micrometers spectral range. Formula for integral spectrum of light scattered in near-critical medium was obtained.

We tried to probe photon path statistics by analyzing the change of speckle contrast with different coherence length of source. The speckle contrast is strong function of both photon path statistics inside scattering media and coherence function of a source. By introducing explicit formula for speckle contrast, we can relate photon path statistics with measured speckle contrast and coherence of source in reverse manner. To realize this idea, we formulated this relationship and performed several MC simulations and basic experiments for various scattering media. Although the present result is very rough, it shows some possibility of using this method to find photon propagation statistics inside turbid media such as tissues and thin polymer film.

Scanning optical far and near-field microscopes resolution is limited by light spot size used to scan a sample. The focusing elements in scanning microscopes are ordinary used lenses with dimensions of rather more than a light wavelength. The focus spot size of such lens is limited by well-known diffraction limit. However, if a lens dimension is comparable with a light wavelength the Fresnel's diffraction formula of focus spot size calculation is not suitable. At present, there are no data about theoretical or experimental studies of the small lenses and even about their fabrication methods. A new fabrication method of small spherical glass lenses with diameters from 1 micrometers to 100 micrometers is considered, and some theoretical approaches to the focus spot size calculation and its experimental measurement are discussed in the paper. The lenses fabrication method is based on melting of fine glass powder with oxygen-acetylene burner with subsequent lenses selection under conventional light microscope. To calculate a spot size of the small lens the Mie theory of light scattering in near field by small spherical particles has been used. The calculated light intensity diagrams for spherical lens in near field are presented.

The dependencies of the spectral half-width of intensity fluctuations of light multiply scattered by disk-shaped and spherical particles have been experimentally studied for the cases of circular and linear polarization of incident light. It is shown that the rate of polarization decay for biotissues depends on the polarization state of probe light.

Results of the contrast analysis of time-averaged dynamic speckle patterns in application to monitoring of the structure modification of the thermally treated collagenous tissue such as cartilage are presented. The modification presumably induced by the bound to free water phase transition in the matrix of the treated tissue cause the specific feature of evolution of the time-averaged speckle contrast with the change of the current temperature of modified collagen tissue. This evolution appears as hysteresis associated with irreversible changes in tissue structure.

Study of influence of an absorption of scattering media on the residual polarization of backscattered linearly polarized light is carried out. Approximate expression describing dependence of the degree of residual linear polarization on optical properties of disordered media is obtained. Phenomenological theory of multiple scattered field formation due to superposition of partial components with different optical paths in multiply scattering medium and previously described similarity of various statistical moments of multiply scattered optical fields are used to estimate the degree of residual polarization. Suppression of partial components with large values of optical paths causes increase of this parameter for detected backscattered light. This effect is observed at the wavelengths of selective absorption of disordered media. Experimental results obtained for phantom scattering samples such as milk and in- vivo biological tissue (human skin) are presented.

The computer installation intended to capture optical signals with further analysis of the deformation-induced speckle dynamics is examined. Application of the installation for study of chaotic microdisplacements, visualization of surface element rotations and localization of irreversible deformations is discussed.

This work is devoted to the elaboration of polarization correlometry and wavelet analysis of object laser fields, formed by the structured tissues and the development of principles of optical diagnostics of tissue physiological state. The histological sections of physiologically normal muscular tissue of healthy rat heart (group A) and the necrotically (infarct) changed one (group B) have been investigated.

The fractal nature of the majority of biological tissues and intensive development of laser diagnostics in biology and medicine stimulate an interest to the development of new optical methods for diagnostics and analysis of properties of biological fractals. The present paper is dedicated to investigation of polarization properties of cross layers of the bone and myometry tissues with fractal properties.

The process of transformation of polarization and correlation structure of low-intensive laser radiation by the skin is discussed in this paper. The method of matrix modeling of optical properties of epidermis and derma of the skin is suggested. On this basis, the mechanisms of transformation of the polarization of the scattered laser radiation field's state and formation of the coherent biospeckles ensemble are analyzed. The technique of polarization diagnostics of the skin's derma collagen net structure is suggested.

Wavelet analysis of scattered light intensity fluctuations was used to improve performance of speckle correlometry of porous systems. The further development of technique was proposed to study structural characteristics of such systems. The intensity fluctuations of multiple-scattered light is a non-stationary noise-like signal. Previously reported spectral analysis of such signals based on windowed Fourier transformation faces the well-known difficulties in a case of short time series. The effect of aliasing in frequency domain prevent us from determining spectral characteristics accurately. But by use of continuous wavelet analysis it can be defined with maximal time-frequency resolution.

The application of laser measuring system with spatially- modulated probing laser beam for study of properties of thin and bulk scattering media is considered. The diluted human blood of the man was used as the scattering medium. Time- dependent dynamics of scattering properties of blood suspensions is investigated in the course of spontaneous sedimentation and aggregation of erythrocytes.

On the basis of the Bragg diffraction model of coherent- optical interaction of laser radiation with ultrasonic wave, the influence of ultrasound axis position and ultrasound frequency value on the amplitude characteristics of ac photodetector current at the ultrasound frequency was theoretically analyzed. For intermediate scattering regime where the ballistic and low-step scattered light components are comparable in their values, the images of the absorbing squares were reconstructed on the base of the ac current amplitude at 3 MHz frequency and dc current distributions. The possibilities of the acousto-optical imaging of scattering medium were discussed on the basis of the results obtained after comparison with traditional measurements of dc photocurrent distributions.

Methods of analysis of objects characterized by wide variety of sizes, shapes, color and type of dynamics are described. Application of automatic video control systems for granulometric analysis of various metal powders and grinded materials used in dispenser elements of electrovacuum devices is illustrated. The results of color analysis of millet seeds images having different color shade are given. The features of optoelectronic detection and computer diagnostics of complex movements of the freshwater crayfish Daphnia eye are considered.

Analysis of multiple interactions of probe light with moving scattering particles indicates the manner in which scattering occurs. The study of statistical properties of Doppler shifted components of scattered light allows one to diagnose the structure and dynamic properties of scattering medium. In this paper, we consider an influence of the statistical properties of pathlength distributions that characterize the probe light transfer in scattering medium on analyzed dynamic speckle patterns. The convenient way to analyze dynamic speckle and to obtain in such manner the information about dynamic properties of scattering medium is to apply the contrast analysis of time-averaged speckle images known as Laser Speckle Contrast Analysis (LASCA) technique. Possibility to analyze the non-stationary layered media with use of the LASCA technique is discussed. Some manifestations of the statistical properties of the pathlength distributions of scattered field partial components in Doppler shift frequency distributions for these components are studied with use of the Monte-Carlo simulation.

Simulation of irreversible growth in 3D lattices consisting of filled and release cells with certain number of interconnections was carried out. Results of simulations are suggested to use for interpretation of the behavior of dynamic speckles induced by laser light scattering in non- stationary porous media.

When imaging through scattering media it is easiest to visualise a pulse propagating through the material. As the light propagates it is scattered away from its original trajectory and it becomes diffuse, both spatially and temporally. It is important to note that this picture is also valid for short coherence length c.w. light. In order to create a high resolution wide-field image, in an ideal case, it is necessary to select only the unscattered ballistic photons. This may be achieved using the coherence properties of the light. If the beam is initially split into an incident beam and a reference beam then only the unscattered ballistic photons will retain coherence with the reference beam. Therefore only this light will produce an interference pattern. In the wide-field case this interference of light from the object and light from a reference beam is termed holography.

New computer system for modeling and optimization of liquid crystal devices and other optical elements on the base of layered structures is presented. This system may be useful in designing and optimization of usual and projection liquid crystal displays, LC controllers and modulators, birefringent filters, antireflective coatings, Fabry-Perot interference filters, multi-layer mirrors, etc. The simulation of various optical experiments with liquid crystal cells can be carried out.