A major problem in biomedical optical imaging is the fact that image quality degrades with penetration depth : the deeper the imaged object is buried in turbid media like tissue, the less precise is the determination ofits location, size, shape and optical properties. This result comes as a consequence of the very nature of light propagation in turbid media. At very shallow optical depths the majority of photons comprising an optical beam illuminating the medium propagate without scattering and therefore there is small or insignificant distortion of the beam pattern (as demonstrated in the far left image of Slide 1). As the optical depth increases, a larger number of the photons will experience one or a few scattering events causing profound changes in the spatial distribution of the light beam intensity (as seen in the middle image of Slide 1). For imaging depths greater than 10 photon mean free paths, the propagation of light gradually becomes completely diffuse (as demonstrated in the far right image of Slide 1).

Here, we present the results of theoretical experimental studies of the light spectral selection due to the coherent multiple scattering into partially ordered mesoscopic disperse media. The role of coherent effects in random close-packages systems with short-range ordering is discussed. The concentration effects of whitening and darkening for optically soft particles are considered in terms of the amplitude-phase screen model. For close-packed monolayers of highly refracting particles the effects of coherent rescattering are analyzed using a quasi-crystalline approximation of the theory of multiple wave scattering and the radial particle distribution function obtained from the Percus-Yevick equation solution. The same theoretical approach being extended to periodic one- and 3D disperse systems describes the formation of forbidden photon zones in transmission spectra of photonic crystals. Ways of spectral properties controlling for ordered dielectric and metal nanostructures are proposed and analyzed. In addition, the theoretical description of their optical characteristics is developed. Results of quantitative calculations agree well with experimental data found for various types of scattering filters and coatings. The regularities obtained for photonic crystals seem to be fruitful for the creation of novel selective elements based on spatially ordered mesoscopic disperse systems with different structural organization.

Some topics on the light scattering phenomena in random mass fractals are reviewed. First, the basic property of the single forward scattering is introduced. Then, as an example of multiple scattering effects from fractal media, fractal dependence of coherent peaks in the enhanced backscattering is discussed. These two types of scattering phenomena in mass fractals are interesting from a diagnostic or analyzing viewpoint of fractal optics. On the other hand, the third one treats with the generation of fractal speckles, aiming at optical synthesis of desired fractality. Simple methods for producing random intensity distributions with mass fractal properties in diffraction and image regions are described.

Laser speckle is a high-contrast, random interference pattern seen when coherent (laser) light is scattered from a diffuse object. If instead of being solid, the illuminated object consists of individual moving scatterers (such as particles in a fluid), the speckle pattern fluctuates randomly. These intensity fluctuations contain information about the velocity distribution of the scatterers. After a brief introduction to laser speckle and its statistics, this paper reviews the possibilities of analyzing speckle fluctuations to obtain information about the velocity of moving scatterers. The account stresses the close connection between time-varying speckle and the Doppler- based techniques of photon correlation spectroscopy and laser Doppler velocimetry. One particular speckle technique, laser speckle contrast analysis (LASCA), is treated in some detail. The final part of the paper is a review of some biomedical applications of time-varying speckle.

The paper deals with the review of a complex of techniques for optical control of monocrystalline films with polyester film as example. The following characteristics of the polyester film were measured: refraction index; surface roughness; the degree of the films' optical thickness inhomogeneity; the phase variance of radiation passing through the film; total scattering cross-section.

The solution of a problem on propagation of a spherical electromagnetic wave in space, free from sources, in case of isotropic medium on assumption of rotational symmetry, is offered. As a result of solution of the Maxwell uniform equations in a spherical coordinates the detailed analytical expressions for components of fields of axially symmetric spherical E- and H-waves, without use of Hertz's vector, accepted in electrodynamics, are obtained. The analysis of Umov-Poynting vector components with given assumptions is also made.

The gain in one-dimensional photonic band gap structure, containing active layers, is studied. Nonlinearity of the material, caused by Kerr effect, is taken into account. Nonlinear problem of wave transmission through nonlinear multilayered structure is solved using perturbation method. It is shown, that the gain in photonic band gap structure can be essentially enhanced at the photonic band gap edge in comparison with a bulk material having the same optical thickness.

Existence of non-zero residual polarization in case of backscattering of linearly polarized coherent light from semi-infinite disordered half-space is considered. This effect is caused by the significant contribution of the low- step scattered components for the backscattering mode and can be described phenomenologically by using the concept of distribution of effective optical paths of scattered light partial components. Influence of effective optical path statistics on the residual polarization degree was studied in the experiments with various phantom multiply scattering media. Corresponding results are presented.

The simulation of spontaneous cooperative emission (Dicke superradiance) of initially inverted two-level active centers with the randomly oriented transition dipole moments was performed. The self-organization of the diffraction and polarization structure of radiation (inside the total solid angle) for the thin-sheet sample emission is presented.

The paper discussed application of the speckle field interference theory for description of spatial localization of interference fringes generated in interferometers with amplitude splitting of the light beam in white light from extended sources. The Michelson interferometer is used to illustrate direct influence of the spatial coherence degree of interfering fields on the localization area extent of interference fringes.

In optical system with double Fourier-transformation and with an illuminating spatially modulated laser beam, scatterer in an entrance plane and a random phase object in spatial-frequency plane the process of formation of average intensity interference fringes in the plane of the image is considered. It was shown that the optical system can work in shift interferometer mode. The analytical expressions for the contrast of the image of fringes as functions of object's statistical parameters and parameters of an illuminating beam (fringe spatial frequency and beam aperture) are obtained. It is established that in coherent and incoherent optical systems with scatterer in an entrance plane the contrast of the image of sine-wave fringes depends similarly on parameters of object in spatial-frequency plane and parameters of optical system.

A rigorous multiple scattering wave theory for investigation of 2D photonic crystals is used. The use of translation properties of Bessel functions reduces the scattering problem to the linear system. This method is able to provide angular dependence of scattering intensity of the samples of structures formed by different number of circular rods. Some biological tissues, for example the optical tissues of eye-cornea and sclera, can be considered as natural photonic crystals.

Laser light radiation scattered by the system of spheres with various parameters was theoretically investigated by using of the Mie theory of electromagnetic scattering by a single sphere. The calculations were performed for systems of particles whose coordinates were specifically realized in random fashion according to the specified probabilities defined by the approximation of hard spheres. The parameters of model are the same as in the eye lense biotissue and were carried out by using of medical data about internal structure of men lens and some animals. In general the studied model presents the system of homogeneous spherical particles which are randomly distributed in the layer of thickness. We study the optical properties such as scattering effective cross-section and function of correlation in different models.

The paper gives the analysis of local polarization states of scattered speckle patterns in case of transition from low- step scattering to multiple scattering mode. Simple phenomenological approach to the description of polarization structure of speckles caused by interference of perpendicularly polarized optical fields is considered. Experimental results obtained with layered scattering slab consisting of a number of thin Teflon films are presented.

Effective properties of plane stratified bianisotropic structures are found on the basis of 4x4 matrix method without restriction on the ratio of the period of structure and the wavelength of incident radiation. The effective permittivity, magnetic permeability and magnetoelectric dyadics are obtained for isotropic two-layer and anisotropic helicoidal structures in resonant case.

The paper considers the approaches to the finite element method and boundary element method in the problem of light diffraction by micro-optics. A very efficient hybrid method which requires no knowledge of the boundary conditions is introduced to simulate the diffraction of a plane wave by micro-optics. This method offers several advantages over other analysis techniques in terms of both computational efficiency and storage requirements. Diffraction by refractive, diffractive and binary-phase lenses that have subwavelength features is analyzed.

The algorithm suggested in the present paper was developed in order to calculate the refraction of 2D medium which transforms given amplitude-phase distribution on the input plane into required one on the output plane. The design procedure consists of constructing ray trajectories in GOE and numerical calculation of GOE refraction. The numerical calculation results are also discussed.

The aim of present work is to study spatial-temporal structure of electromagnetic pulse with sharp front, propagating in vacuum. The processes of formation and recession of pulse are considered. The specific character of the process under investigation prevented us from using the method of slowly varying envelope approximation. The mathematical basis for the study was calculating the Fresnel diffraction integral for functions of initial pulse frequency spectrum.

Simple polarization-optical techniques, allowing to reveal the presence in a layer of 1D-inhomogeneous (in the field of optical probing) anisotropic medium such symmetry elements as center of symmetry and symmetry axis parallel to the layer boundaries, are presented. The possibilities of the use of these techniques for observing the configuration of supramolecular structure (SMS) of liquid crystal (LC) in the study of orientation phenomena in liquid crystals are demonstrated with some experimental examples.

A procedure of inspection of mass transfer processes by induced femtosecond laser has been suggested that is based on pump-probe Doppler tomography. In the experiments we used mode-locked Ti:sapphire laser with output power up to 150 mW. Pulse duration was 100fs at 100MHz repetition rate. In our experiments focused laser radiation induced on the surface of the target mass transfer processes (melting and convection). The Doppler shifted backscattered radiation was registered by heterodyne scheme based on Michelson interferometer. We have obtained information about depth and distribution of convection flows within melted paraffin bath with high spatial resolution ((delta) z~15micrometers ).

The aim of this study was to determine the best setting for measuring time-of-flight in TMP with a streak-camera. In the first setting, referred to as straight setting, the laser, TMP sample and streak-camera were in a line. In the second setting, referred to as diagonal setting, the streak- camera was placed at a 90-degree angle to the light source. The results indicate that the diagonal setting allows an easier time-of-flight measurement than the straight one in low-consistency TMP. In medium-consistency TMP, however, there are no performance differences between the settings. Nevertheless, if drift in the laser or streak-camera necessitates the use of a reference pulse, the straight setting provides an easier measurement. Neither setting allows the measurement of high-consistency TMP.

Ultrasound modulation of scattered laser light was studied to develop the technique of acoustooptical visualization of the objects imbedded in scattering media. The focused ultrasound wave intersected the laser radiation in a medium. They passed through the medium laser light was collected by a photo-detector. The ac current characterized the optical properties of the zone of intersection of laser and sound beams. On the basis of the suggested model of coherent- optical interaction of laser radiation with ultrasonic wave, the expression for ac current was derived taking account of finite size of the laser beam diameter and the Gaussian distribution of the laser beam intensity, when the Bragg angle was much less than 1. The influence of medium scattering properties and geometry of experiment on the ac photo-detector current and signal to noise ratio was analyzed. With a use of theoretically predicted and experimentally confirmed results, the images of the absorbing half-plane using distributions of the ac amplitude of the current at 3 MHz ultrasound frequency and dc signal were reconstructed in weak scattering media. The possibilities of the acoustooptical imaging were discussed on the basis of the results obtained after comparison with traditional measurements of dc photocurrent distributions.

Bragg diffraction of optical waves has been analyzed for an isotropic elastic optical medium (EOM) on hypersonic waves (HSW) excited by zero and minus-first space harmonics of slow electromagnetic waves in the MW band which propagate in a periodic structure placed at the medium boundary. The simple analytical relations for calculation of frequency- response characteristics (FRC) are obtained for acousto- optical interaction in such media.

The analysis of thermal errors of fiber-optical gyroscopes using Sagnac interferometer is carried out. The temperature regulating system of single blocks and elements of a device using reverse thermal Peltyer elements is considered. The recommendations for improvement of precision, efficiency and reliability of fiber-optical gyroscopes with the thermal control system on Peltyer elements are worked out.

New coherence methods of microobject parameter measurements are analyzed in connection with the development of the automatic data processing systems, of the phase0shifting holography methods, as well as with the appearance of new active elements permitting to carry out autodyne measurements. The simple method of parameter inspection of microobject vibration is based on usual optical microscope with TV camera is discussed. The method based on the phase- shifting interference pattern consequence analysis using the Fourier transformation is given. For the first time the possibility of the returning of the non-harmonical vibration spectrum of the object in phase-shifting holographic interferometry has been considered. The semiconductor laser autodyne systems have been used to elaborate new technologies of fast-changing processes control. The use of semiconductor laser autodyne for the diagnostics of the microsaccidic eye movements, known as eye tremor, whose amplitude does not exceed several microns has been shown.

The paper presents the results of polarization-correlation investigation of multifractal collagen structure of physiologically normal and pathologically changed tissues of women's reproductive sphere and of skin. The technique of polarization selection of coherent biotissues' images followed by determination of their autocorrelation functions and spectral densities is suggested. The correlation- optical criteria of early diagnostics of pathological changes' appearance of myometry (forming of the germ of fibromyoma) and of skin (psoriasis) are determined. The present paper examines the possibilities of diagnostics of pathological changes of biotissues' morphological structure by means of determining the polarizationally filtered autocorrelation functions (ACF) and corresponding spectral densities of their coherent images.

The object of this research is to study the complex of polarization parameters of the field of laser radiation scattered by system of the human blood formed elements and bioliquids. Polarization statistics of laser biospeckle fields of human smear was studied.

The fractal nature of the majority of biological tissues and intensive development of laser diagnostics in biology and medicine stimulate the creation of new optical methods in diagnostics and analysis of biological fractals properties. The present paper investigates the polarization properties of bone and myometry tissues transverse layers.

The present paper deals with the research of laser radiation polarized structure transformed by biotissue crystalline phase. It is important in creating optical methods of diagnostics of biotissue orientation and mineralized structure, as well as in modeling biocomposite materials.

The purpose of the given work is the development of an optical model of bone tissue orientational and crystalline fractal structure and its experimental approbation.

The presence of two or more distinct local maxima in the power spectrum of radiation results under certain conditions in appearance of peculiarities in interferometer temporal signal. These peculiarities are manifested as a single coherent trough (minimum) in envelope of interferometer signal and as a (pi) -jump of phase of this signal in the point of envelope's trough. The coherent trough can be used as a measuring signal in the partial coherence interferometry. The conditions for observation of single coherence trough in envelope of interferometer temporal signal are discussed.

Gas-bubble superlattices produced in certain metals upon ion implantation of inert gases are treated for the first time regarded as weak 3D photonic crystals for the soft x-ray radiation. Computations based on electromagnetic transfer matrix method show that the bcc superlattices of helium bubbles in molybdenum with the lattice constant of 5.0 nm and bubble diameters of 2.4 and 3.0 nm will exhibit selective reflection of soft x-rays with wavelengths around to 10 nm. The reflectivity peaks have relative widths of less than one per cent and peak values in the range of 2- 15%, depending on the bubble size and helium concentration in bubbles and in the metal host.

Method of polarization visualization of superficial layers of multiply scattering medium containing macroinhomogeneities based on the analysis of polarization patterns of a backscattered linearly polarized light is discussed. The polarization properties of a backscattered light were studied for phantom scattering media (diluted milk with low concentrations). The influence of media scattering properties on inhomogeneity image is obtained by use of polarization degree and normalized scattered intensity as visualization parameters is discussed. Quality of reconstructed images was estimated in terms of spatial resolution and image contrast. Depth resolution of the considered polarization imaging in the backscattering mode is discussed. Phenomenological description of the polarization image formation is carried out by means of the concept of statistical distribution of effective optical paths of partial components of scattered optical field.

This paper is dedicated to the analysis of first- and second- order statistics of speckled speckles. Statistical properties of Fresnel and Fraunhofer doubly scattered and cascade speckles are described.

Speckle-modulated laser fields arising at in vitro measurements of different types of human cataractous lenses have been investigated experimentally. Computer analysis of digital images has allowed to estimate of destruction of the spatial coherence of a laser beam scattered by a turbid lens. Applied speckle-technologies have permitted the range of retinal angular resolution to be estimated with the help of laser retinometer at the stage of preoperative cataract diagnosis. Effect of saturation of the average speckles size in multiple-scattering biotissues gives good opportunities to determine preoperative retinal visual acuity for any type of cataracts in vivo.

Imaging of absorbing inhomogeneity hidden in the multiply scattering media by means of the CW transillumination technique is considered. The effect of inversion of spatial distribution of transilluminated intensity in the region of inhomogeneity shadow was demonstrated in the experiments with phantom scattering object such as rectangular Teflon plate with cylindrical channel filled with water solution of black ink as absorbing substance. Qualitative analysis of the observed shadow inversion effect described as the manifestation of the image projection function peculiarity is carried out by means of Monte-Carlo simulation.

A simulation for a tomography reconstruction of an internal structure of the strongly scattering cylindrical body was carried out. For this purpose Photon Average Trajectories method was applied with several conventional CT algorithms such as the Max-Entropy algorithm MART and the least square algorithms NNLS and LSQR. The comparison of the reconstruction results obtained using these algorithms with ones obtained using MMTOAST10 program package based on diffuse equation Finite Element Method solver was carried out. It was shown that a satisfactory quality of the reconstruction was attainable already after few seconds of calculations at PC Pentium III for trajectory algorithms. The same quality of reconstruction with MMTOAST10 was achieved after about 1000 seconds.

The comparative investigation of blood plasma and serum polycrystal layers properties was executed. Formation of microcrystals by desiccation of blood plasma is shown. Such crystals are absent in serum layers. The formation of thrombus at blood serum preparation and, as a result, lack of protein molecules is the reason of the difference. The possibility of Wiener spectra application for analysis of formed crystal structure disorder is shown.

Method of eye iris structure characterization using statistical and spectral analysis of iris color images is considered. Results of study of the iris structure images for large group of individuals are presented. Potentialities of the suggested technique as applied for medical application and personal identification are discussed.

In this work we are going to discuss a role of speckles in laser-Doppler. Despite the speckle approach and laser Doppler were developed separately the both are used to describe the phenomena of the intensity oscillations on the photodetector caused by dynamic light scattering. Actually, those techniques are used when an information about the velocity of moving object must be obtained. Recently it was noticed by David Briers that finally both techniques give the same quantitative answer and might be integrated in one approach having advantages of both. By this work we tried to extend the speckle approach to the work on laser Doppler. We will show our own way in which the both approaches could be integrated in one. The contents of the presentation: first a short introduction into the subject will be done and main goals of the work will be pointed out. Then we will overview shortly two interferometric methods, laser-Doppler and time-varying speckle, trying to find what are the similarities and distinctions between of those. Next, our theoretical framework on integrating of two techniques in one will be proposed. We will show you some experimental validation of our approach and a possible practical application of the one. And finally, conclusion and summary.