Measurement of photon-number statistics of fields composed of photon pairs generated in spontaneous parametric down-conversion pumped by strong ultrashort pulses is described. Finite detection quantum efficiencies, noises as well as possible loss of one or both photons from a pair are taken into account. Measured data provided by an intensified CCD camera are analyzed along the developed model. The joint signal-idler photon-number distribution is obtained using the expectation maximization algorithm. Covariance of the signal and idler photon-numbers exceeds 98%. Entanglement area of the correlated photon pairs is determined.

In this paper we present analysis of the dynamics of an optical system combining two kinds of nonlinearities. In our model we analyse an optical system in which a second-harmonic generation (SHG) takes place in the resonator configuration with an added intracavity Kerr-like nonlinearity. So, the nonlinear medium in the cavity is characterized by its second χ⁽²⁾_2ω and third χ⁽³⁾_ω,-ω,ω nonlinearity parameters (Kerr process affects the fundamental mode only). The extended equations of motion for the fundamental and the second-harmonic amplitudes have been derived for the classical case. We have found that for the special case of a coherent pumping, the equations have an analytical periodic solution. Generally, the system is non-integrable and we have investigated it numerically for two types of external pumping and the results were compared with those obtained for the pure SHG case. For the periodical motion the influence of the Kerr nonlinearity is insignificant because the constant χ⁽³⁾ is much smaller than χ⁽²⁾ (χ⁽³⁾/χ⁽²⁾ < 10^-4 in our case). The Lyapunov spectrum analysis as well as the analysis of information dimension show that in the chaotic case the influence of Kerr nonlinearity on the dynamics of the system is more significant. We have obtained quite a different dynamics on chaotic attractors. However, the stability of the system remains almost unchanged. The influence of the system parameters on the dynamics and the stability of the SHG process with the Kerr nonlinearity is also investigated.

Optical parametric process occurring in a photonic-band-gap planar waveguide is studied from the point of view of nonclassical-light generation. Nonlinearly interacting optical fields are described by the generalized superposition of coherent signals and noise using the method of quantum linear corrections to a classical strong mean-field' solution. Scattered back-propagating fields are taken into account. The possibility to generate squeezed light and light with sub-Poissonian statistics in dependence on the strength of scattering, strength of nonlinear interaction, linear and nonlinear phase mismatches as well as characteristics of the states of optical fields incident on the waveguide is discussed in detail.

If there are correlations between two qubits then the results of the measurement on one of them can help to predict measurement results on the other one. It is an interesting question what can be predicted about the results of two complementary projective measurements on the first qubit. To quantify these predictions the complementary knowledge excesses are used. A non-trivial constraint restricting them is derived. For any mixed state and for arbitrary measurements the knowledge excesses are bounded by a factor depending only on the maximal violation of Bell's inequalities. This result is experimentally verified on two-photon Werner states prepared by means of spontaneous parametric down-conversion.

In this paper we show that the codirectional Kerr nonlinear coupler can generate Schrodinger-cat states, in particular, Yurke-Stoler states based on the values of the interaction parameters. We show this analytically through s-parameterized single-mode quasiprobability distribution functions. We confirm this fact also in the evolution of the phase distribution.

We investigate a compact source of entanglement. This device is composed of a pair of linearly coupled nonlinear waveguides operating by means of degenerate parametric downconversion. For the vacuum state at the input the generalized squeeze variance and logarithmic negativity are used to quantify the amount of nonclassicality and entanglement of output beams. Squeezing and entanglement generation for various dynamical regimes of the device are discussed. The influence of losses is investigated in detail.

We propose new method of an improving quality of a ring cavity which is imperfect due to non-unit mirror reflectivity. The method is based on using squeezed states of light pulses illuminating the mirror and gradual homodyne detection of a radiation escaping from the cavity. Using measured data we can improve the state leaving the cavity by a single displacement and single squeezing operation performed. We discuss contribution of this method in process of storing unknown coherent and known squeezed state and generation of squeezing in the optical ring cavities.

In this contribution, an overview of applications of white-light spectral interferometry in dispersion characteriza- tion of optical fibers is presented. First, spectral-domain intermodal interference is analyzed theoretically at the output of a few-mode optical fiber alone and at the output of the optical fiber in a tandem configuration with a Michelson interferometer. The theoretical analysis is performed under general measurement conditions when a broadband source and a spectrometer of a Gaussian response function are considered and when the first-order and second-order intermodal dispersion effects in the optical fiber are taken into account. Second, the theoretical analysis is performed for three different examples of dispersion curves of two-mode optical fibers and the effect of the limiting factors is specified. Finally, the theory is accompanied by the corresponding experiments for mea- suring either the intermodal dispersion in circular-core and elliptical-core fibers or the dispersion of birefringence in the elliptical-core fiber.

Diffraction is analyzed for oblique propagation of light beam under a large angle. Fresnel diffraction approximation is valid provided the beam is deflected into the direction of oblique propagation, the structure of the diffraction screen is projected onto the plane perpendicular to the propagation direction, and the diffraction pattern is observed in the plane perpendicular to the propagation. The task is illustrated by the diffraction due to a circular aperture.

Dispersion of ellipsometrical angles analyzed using theoretical model as well as over measured data is presented. Binary multilayer grating is modeled via rigorous coupled wave method. The special attention is devoted to additional oxidation of inter-dot area and to an interaction of finite optical beam with super-long-period structure. The results are discussed in the relation to experimental data.

We present an achromatization procedure for multiple images obtained with the Talbot illuminator. It consists on joining in one optical arrangement an achromatic Fresnel diffraction setup and the kinoform Talbot illuminator. In this way the multiple images produced by the Talbot illuminator are obtained using totally incoherent light, both spatially as well as temporally. We present the experimental results which confirm the correctness of the proposed approach.

The communicate presents a new interpretation of the Talbot effect for periodical objects limited by finite apertures. According to the proposed approach, a self-image of a real, finite object is a superposition of deformed images of an elementary cell. The singular elementary cell image is equivalent to that formed in a proper optical system. The theoretical description makes possible to define a structure of self-images. Particularly, the approach enables a determination of apertures' dimensions which lead to self-images of a reasonable quality in a desired region of an image plane. The theory is illustrated and verified by numerical simulations.

The optical vortex interferometer (OVI) is based on the regular net of optical vortices, which is generated by the interference of three plane waves. In this paper the use of OVI to phase determination is discussed. In classical interferometry the phase of the wave is determined in respect to the phase of the reference wave. The quality of reference wave must be checked by some other methods (like parallel glass plate test). It is shown that in case of OVI the phase of the investigated wave can be reconstructed without referring to any other wave.

In an interferometer based on optical vortices there are generated regular net of phase singularities. There are two kinds of optical vortex named positive and negative. The sign of the vortex is often named a topological charge of the optical vortex because its existence is related to the characteristic of the geometric wavefront. The ability to determine the sign of the optical vortices in the experimental measurements may be used to reconstruct the wavefront. In this paper authors present the experimental method to determine the sign of the optical vortices.

In the paper, we briefly review properties of nondiffracting and vortex beams and disscuss their applicability to the particle manipulation and the transfer of information. An efficient method enabling a possibility to arrange the beam spots into patterns and arrays of a predetermined shape is also proposed and examined. A particular attention is focused on experiments providing nondiffracting patterns composed of spatially separated or coaxial vortices of different topological charges. The experiments are realized by a spatial light modulator and are prospective for the design of variable optical tweezers and spanners. The coaxial mixed vortex fields are promising for a capacity-increased encoding of information.

In the focus of our attention is the holographic Fourier Transform element (HOE-FT) used in holographic memory system (HMS). The information from page composer is transformed into the crystal and recorded in form of Fourier Transform holograms. The research aims at determining HOE phase function as well as at checking the possibility of its usage in optical memory system. Therefore, spot diagram analysis, points spread function and aberration analysis are used.

A phase-locked loop method is applied in processing the spectral interferograms resolved in a narrow spectral range in a dispersive Michelson interferometer including optical elements. The unwrapped spectral fringe phases with 2π ambiguity are determined and a simple procedure in removing the ambiguity is applied to obtain the effective thicknesses of the optical elements knowing their dispersion. The effective thicknesses determined in two cases are compared with those obtained by measuring the equalization wavelengths. A Fourier transform method is applied in processing the spectral interferogram resolved over a wide spectral range in a slightly dispersive Michelson interferometer including a cube beamsplitter. The ambiguous spectral fringe phase is determined and a procedure in removing its ambiguity is applied to obtain the effective thickness of the beamsplitter.

A new approach to surface roughness measurement based on the digital two-wavelength holographic interference microscopy with the synthetic wavelength is presented. Two holograms of a randomly rough surface are recorded step by step at two wavelengths by means of a CCD camera. Both holograms are numerically reconstructed. Two reconstructed waves obtained numerically interfere. The surface roughness parameters may be determined from the interferogram.

Short analyze and some results of interference imaging of refractive index distribution in photorefractive records in the LiNbO₃ sample are presented. The presented result shows that an easily readable image can be obtained when refractive index is modulated only in direction parallel with interference fringes. For this purpose, it is useful to use Mach-Zehnder interferometer what allows adjusting the interference fringes to desired position. Obtained images of records of a light field with aperiodic distribution of intensity show that refractive index profiles do not correspond to profile of light intensity or intensity of internal electric field (which is formed by the sample illumination). It is more like the profile of distribution of carrier concentration trapped on the donors or profile of square of the electric field when gradient of refractive index is parallel or perpendicular to c axis of the crystal, respectively. This result leads to necessity of modifying explanation of mechanism of photorefractive record creation. At least in investigated LiNbO₃:Fe.

We present the architecture and code design for a highly scalable, 2.5 Gbis per user optical code division multiple access (OCDMA) system. The system is scalable to 100 potential and more than 10 simultaneous users, each with BER of less than 10^-9. The system architecture uses a fast frequency-hopping, time-spreading codes. Unlike frequency and phase sensitive coherent OCDMA systems, this architecture utilizes standard on-off keyed optical pulses allocated in the time and wavelength dimensions. This incoherent OCDMA approach is compatible with existing WDM optical networks and utilizes off the shelf components. We discuss the novel optical subsystem designs for encoders and decoders that enable the realization of a highly scalable incoherent OCDMA system with rapid reconfigurability. A detailed analysis of the scalability of the two dimensional code is presented. Broadcast and select network deployment architectures for OCDMA are discussed.

Using of several sophisticated optical techniques is reviewed to test the flatness of semiconductor wafers and to measure thin-film residual stresses, induced by various technological processes. Thin silicon membranes have been also inspected to obtain the membrane tension values and thickness variations. Besides this, experimentally by using of Laser Doppler Vibrometer the dynamics of MEMS microcomponents has been studied, too. In the paper, specific features of the methods, where performances and limitations, together with some remarks, regarding practical experiences of the exploitation, are reported.

In this paper we present the proposed modification of 2-D wavelength/time (WIT) decoder¹ by placing the second optical hard-limiter (0-HL) after decoder's last optical coupler. The MA1 improvement of the 2-D W/T Optical Code Division Multiple Access (0-CDMA) system for the cases of 2D WIT decoder with one and with two 0-HLs is analyzed. Average value of signal-to-interference difference (SID) is used as the MA1 merit. The model of such 2D W/T 0-CDMA system for numerical calculation of the SID is proposed and presented in this paper. In the analyzed system, 2-D WIT Generalized Multiwavelength Prime Codewords (GMWPC), which are generated by algorithm reported in² are used for achieving multiple-access. We assume the implemented 0-HL proposed in ³. The properties of such 0-HL were approximated [4] and its two ideality parameters, which characterize the measure of its ideality, were defined. The input and output time optical pulses sequence of W/T 0-CDMA decoder is numerical simulated. Dependencies of SID versus the weight of codeword and the number of active users in the system are presented. The influence of the properties used 0-HLs is evaluated.

Polymer display based on a movable membrane designed in MOEMS technology may be an alternative for other display devices. The display consists of two plastic elements. The first one is a planar waveguide. It is coated in metal with electric contacts etched in it. The second element is a metalized membrane with a matrix of pillars functioning as pixels. The simplicity of the setup makes it cheap and easy for mass production. On the other hand, each size of the display has to be optimized independently, which may be a problem. When deciding on the size of the matrix one has to optimize several interconnected parameters, which decide on the functioning of the display. In this paper we describe the modeling process for a 20×20 pixel matrix with an active display matrix area of 5×5 mm².

This article describes the laser system for measurement and evaluation of functional geometrical parameters of the commutator body. Measuring principle is based on optical detection of boundaries of gaps, segments and lugs on rotating commutator body by means of laser beam.

Air fluorescence yield is defined as the number of photons, produced by a charged particle, per meter of travel in the air. The excited molecules emit light in the near UV and in the visible region between 300 nm and 400 nm. We describe the simple light collection system for analysis of the faint signal.

In the paper a contactless method capable to measure a surface unevenness is described. The method is principally based on oblique illumination of the rough surface with normal viewing of the illuminated area by CCD camera. The light intensity distribution in an image read by camera involves inherently information about the surface microprofile. The amount of light scattered to the normal direction of surface follows the relations of light diffraction and shading on surface hills, grains and dimples in microscale scene. In the paper the contribution of these effects on the overall light scattering is discussed and the correlation length of the roughness is used as a criterion to an accounting whether the diffraction is important. A quantitative calibration procedure has been proposed in order to evaluate the main surface roughnesslwaviness parameters.

In case of total reflection at a boundary surface between two different optical media, the ray reflected at the boundary is spatially shifted with respect to a point, where an incident ray intersects the boundary. The light penetrates into the second medium and the evanescent electromagnetic wave propagates along the boundary. The described problem is called the Goos-Hanchen effect. Our work describes an influence of the Goos-Hanchen effect on the imaging properties of optical systems and it is derived a differential equation of a wave-front meridian that corresponds to a reflected bundle of rays. It is shown that the wavefront can be described by d'Alambert differential equation. This equation make possible to determine the coordinates of individual points on the wave-front meridian. Moreover, the paper also investigates the influence of total reflection on the value of the Strehl definition of the reflected ray bundle.

The work analyses an influence of the change of object position on the accuracy of optical and optoelectronic measurement systems using both geometrical and diffraction theory. It is shown that in case of the change of position of the measured object the imaging properties of the used optical measurement instrument are changed. This position change affects the image quality. If some optical measurement system is aberration free for a specified position of the measured object, then for other object positions the optical system has aberrations. The consequence of this effect is the change of the measurement accuracy for the specific optical system. The described effect is not removable on principle and it is necessary to take account to it in high accuracy measurements.

The investigations of electrons collective excitations on metal surface is important for deeper understanding both the metal properties and the response of the metal to an accident electromagnetic radiation. It is a matter of common knowledge that the properties of metal can be substantially modified as its physical dimension are reduced to the nanoscale. In such case a lot of experiments have shown the variation of work function, but there still exist the discrepancy between them and theoretical results. It seems to be really important to push the theory just a bit further. Here the work function is exactly defined function of the electron density and wave number what allows to take into account an influence of the uncertainty principle in obtained results.

The paper demonstrates two microinterferometric techniques applied to fibres and other small transparent objects. They enable simultaneous determination of the directional refractive indices and the thickness of isotropic and anisotropic single-medium fibres. The techniques are based on the Pluta birefracting microinterferometer Biolar PI. The paper includes comparison of different approaches and the error analysis.

The intensity of the reconstructed image in the transmission holographic microscope is depth discriminated as it is in a transmission confocal microscope. The effect is the consequence of the limited coherence of the illumination - hence no scanning system is needed. As the technique is based on the incoherent holography, the phase image component may be reconstructed in addition to the intensity one. The overall imaging process is coherent. Its three-dimensional coherent transfer function is derived using the first Born approximation of the scattering theory. In order to understand clearly the imaging process of the microscope, two-dimensional imaging characteristics are derived in this paper in addition to the three-dimensional one, and images of a rectilinear slit as a model two-dimensional structure are calculated for various amounts of defocus. Theoretical axial distributions of the intensity integral are compared with the experimental ones.

This article treats of using the 3D optical scanning topography as one of possible methods of an analysis of the cotyle deformation. The object of this experiment is to quantify the decrease of cotyle material. The scanning object is polyethylene coxa cotyle ABG I.

It is well-known from the theory of optical imaging that optical systems generally show a presence of a chromatic aberration, which originates from a variation of the refraction index of glass on the wavelength of light. The chromatic aberration must be well corrected in order to obtain a good quality of optical image. In practice, it is used a proper combination of optical elements manufactured from different types of optical glass with a different dispersion in order to suppress the chromatic aberration. Our work shows a way how to correct spherochromatic aberration using a system of thin aspherical layers. The equations are derived for determination of parameters of thin layers with respect to a required spherochromatic aberration.

Optical lens systems have always chromatic aberration. Optical systems that are used for imaging in optical instruments, e.g. in binoculars, microscopes, cameras and projectors, have chromatic aberration corrected very well in order not to reduce imaging quality. In many cases, it is necessary to use optical systems with relatively large chromatic aberration. The optical systems that are characterized by a chromatic aberration of a predefined form are called hyperchromats. Our work describes a theory of hyperchromats with a linear dependence of longitudinal chromatic aberration on wavelength. The equations are derived for calculation of basic design parameters of these optical systems and several examples of calculations are shown. Mentioned optical systems can be used especially in 3D imaging systems and confocal microscopy.

In the geodetic measuring instruments optical systems with internal focus are used at present. It enables reaching significant shortening of the optical set and the use of dust-proof mechanical construction of these systems. It results from the theoretical analysis of the optical features of these systems that the anallactical point is not solid in the process of focusing but it is shifted along the optical system axis. This elaboration shows the impact of this shifting on accuracy of the geodetic measuring and suggests the way of compensation of this error during the measuring process.

Principle, parameters and selected applications of the optical profilometer MicroProf FRT (Fries Research & Technology GmbH) in determining surface quality are presented in this contribution.

The cotyle implantate is abraded in the body of patient and its shape changes. Information about the magnitude of abrasion is contained in the result contour map of the implantate. The locations and dimensions of abraded areas can be computed from the contours deformation. The method called the single-projector moire topography was used for the contour lines determination. The theoretical description of method is given at first. The design of the experimental set-up follows. The light grating projector was developed to realize the periodic structure on the measured surface. The method of fringe-shifting was carried out to increase the data quantity. The description of digital processing applied to the moire grating images is introduced at the end together with the examples of processed images.

Material surface modification was carried out by laser alloying technology with an additional material. The final effects are based on micro-structural changes in the surface layer, furthermore by changing the material composition in the surface. Sic powder was applied on CSN 41 20 10 steel into melting pool generated by interaction with the moving C0₂ laser beam. Numerical modelling of the temperature field on the substrate appears like a good way to optimalization of process parameters. The final surface structures are presented and analysed by scanning electron microscopy. The microhardness of treated layers in comparison with substrate is described too.

A diffractive structure (holographic lens: HL, diffractive optical element: DOE) can be included into compound objective as one of its parts making a hybrid objective. In this paper a possibility of correcting field aberrations in a triplet hybrid objective is analyzed. The solutions for aplanatic correction in the case of achromate, apochromate and quasi-superachromate are presented and illustrated with exemplary objectives. Correction of field curvature is considered in the case of hybrid triplet achromate.

The progress of laser technology during the past twenty years made it possible to extend the time resolution of optical experiments down to picosecond and femtosecond time scales. In this paper, the state-of-the-art techniques of ultrafast optical spectroscopy are reviewed. It is shown, how these can be used to monitor directly dynamics of elementary excitations in semiconductor nanocrystals and how, in turn, understanding ultrafast carrier processes makes it possible to tailor the properties of these structures for application in photonics, nanoelectronics and spintronics.

Review of thermo-optic effects in gain media of diode pumped lasers is presented. Methods of modeling and compensation of such effects are discussed. Results of characterization of end-pumped lasers by means of energetic and caustics measurements techniques are presented and discussed. Application of Wigner distribution method for characterization of aberrated laser beams is presented and discussed. Thermally induced astigmatism was observed for the anisotropic rods at high heat load.

Nonlinear absorption and refraction effects are of particular interest for areas like optical communication (all optical switching and limiting). Nonlinear parameters of ZnSe, GaAs and polythiophene (polythiophene/zeolite complex) have been the subject of investigation using an Cr: Forsterite fs laser source with an output wavelength of 1250 nm, i.e. in a spectral region which plays important role for optical communication systems. The obtained values of nonlinear refractive index and two photon absorption coefficient are compared to theoretically predicted values. Beside the original transmittance Z-scan technique a modified Z-scan technique, which allows the sample transmittance and fluorescence being registered simultaneously was employed. The results are compared with a previously introduced theoretical model^15,16. We demonstrated, that the recently developed low bandgap conductive polymer polythiophene shows nonlinear absorption followed by the luminescence in the visible. In addition, there is a different behavior of nonlinear absorption and luminescence for polyalkylthiophene and polythiophene/zeolite complex which may be explained by the supramolecular complexation of polythiophene in zeolite.

We present a fully digital stabilized semiconductor laser system designed to operate as a fiber-optic front-end o a pulsed power laser PALS (Prague Asterix Laser System). With an operating wavelength of 1315.15 nm the stabilized laser is based on a telecommunication single-frequency DFB (Distributed FeedBack) diode. The lines are detected by means of linear absorption in a heated cell filled with thermally dissociated iodine. The detection scheme is based on a derivative spectroscopy with a current frequency modulation and thermal wavelength control. The detection chain together with stabilization servo loop is fully digital represented by signal-processing single-chip controllers. The operation of the controllers can be monitored by PC via CAN (Control Area Network) bus. The algorithm of the absorption spectrum scanning, line selection and locking makes it possible to operate the laser in a maintenance-free regime, monitored only by a "ready" signal from a control panel of the PALS.

We present a design of a stabilized laser system, an etalon of the optical frequency at the 1.5 μm band following the demands of the telecommunication industry in the Czech Republic. Our laser system employs a DFB laser diode in a two stage stabilizing scheme. The linear absorption arrangement with an acetylene filled absorption cell of a pressure about 1 kPa is used to lock the laser to the Doppler-broadened lines. To achieve a reliable and robust stabilization of the laser frequency we arranged a two-loop digital servo-system overcoming the problem of a narrow locking range of the detected transition. The wavelength of the laser is modulated by current and the servo-control and tuning is performed by a fast and precise thermal control. To achieve the resolution of the weak sub-Doppler transitions we assembled a locking scheme via frequency-modulation spectroscopy to the high finesse cavity. The system is assembled using predominantly fibre-optic components. A technology of acetylene absorption cells with AR coated windows is presented as well.

The slit scan method was implemented for registration of intensity profiles along the caustics of a laser beam. Inverse Radon transform of spatially normalized intensity profiles enable us direct computation of Wigner transform of real laser beam. The Rayleigh range, divergence angle, beam quality factor, global degree of coherence and some information of wavefront aberration can be determined in such a simple way. This procedure was applied for investigation of the aberrated laser beams generated by cw and pulsed diode pumped lasers.

The study resulted in evaluating coherence properties of laser diode modules (LDM), which are offered and sold by acollaborating company'. Besides, a method to measure very short coherence lengths was elaborated. An improvement of the LDM properties was suggested and the first experiments accomplished.

This paper presents practical applications of scanning the laser beam by mechanical devices and by CCD camera. We have measured characteristic parameters of the laser beam by using a pinhole, a knife-edge and a CCD camera based profilers. Results have been mutually compared according to quality parameter M². All methods were found suitable to measure the real beam profile with respect to nearly same results.

With PHELIX (Petawatt High Energy Laser for heavy Ion EXperiments) a high energy/ultra-high intensity laser system is currently under construction at the GSI (Gesellschaft für SchwerIonenforschung, Germany). In combination with the high current high energy ion accelerator facility this will provide worldwide unique experimental opportunities in the field of dense plasma physics and inertial fusion research. In the long pulse mode the laser system will provide laser pulses of up to 5 kJ in 1-10 ns pulses. In the high intensity mode pulse powers in excess of 1 PW will be achieved. For this the well known technique of chirped pulse amplification (CPA) will be implemented. A new CPA stretcher-compressor setup for the PHELIX laser was calculated and designed. A 4-pass single-grating stretcher and a 4-pass single-grating test compressor, both with a full transmission bandwidth of 16 nm, as well as the compact single-pass compressor for the final pulse compression will be presented. Spatial chirp and spectral phase aberrations of the stretcher were optimized. We discuss the dependence of critical alignment tolerances on the angle of incidence and show the effects on the temporal pulse shape.

Application of optical dust-meters to research of work efficiency of dust collectors in ship equipments need wider interpretation of used results for the sake of specific conditions. On the base of measurements of indicatrix cross- section for laser light scattered on dust particles, having different granularity, one obtained distribution curves which allow to determine the difference of interaction in dependency on granularity and type of dust material. The interpretation of obtained results can be an useful index damaging dust influence on living organisms and ships equipments as well.

Assuming that the Compton phenomenon is mainly responsible for the scattering in the block of metal, there was calculated the deposit of radiation at the bottom of the cylinder originating from its wall. The calculation was made for the primary spectrum 0 - 6 MeV given for Clinac accelerator. Klein - Nishina relations were taken as describing an elementary scattering event. The radiation intensity recorded on photographic material was compared to that evaluated as the incoherent summation of contributions. Supposing the caustics arising it was shown the possibility of the change of the intensity distribution.

Two optical measuring methods were used to describe the form of a plaster model of a human vocal folds. The method of the classical shadow moire topography with illumination of a specimen by incoherent parallel beam of light trough a linear grating and the method of an interference modulated laser beam using for illumination of the specimen and a reference plane screen located in front of the specimen (object). The two pictures registered by CCD camera and a computer PC are subtracted and the absolute value of their difference gives the moire interferograms with good contrast. Using by computer realized FFT and the space filtration of Fourier spectrum we get a position of a contour line system defining the form of the studied object.

Symptom of cervical dentine hypersensitivity attacks from 10% to 15% of population and causes an uncomfortable pain during contact with any matter. Sealing of open dentinal tubules is one of the methods to reach insensibility. Laser as a source of coherent radiation is used to melt dentine surface layers. Melted dentine turns to hard mass with a smooth, non-porous surface. Simulation of this therapy was made in vitro by means of LASAG Nd:YAG pulsed laser system KLS 246-102. Eighty human extracted teeth were cut horizontally to obtain samples from 2 mm to 3 mm thick. First experiments were done on cross section surfaces to find an optimal range of laser parameters. A wide range of energies from 30 mJ to 210 mJ embedded in 0,3 ms long pulse was tested. Motion in X and Y axes was ensured by a CNC driven table and the pulse frequency 15 Hz was chosen to have a suitable overlap of laser spots. Some color agents were examined with the aim to improve surface absorption. Scanning Electron Microscopy was used to evaluate all samples and provided optimal values of energies around 50 J.cm^-2. Next experiments were done with the beam oriented perpendicularly to a root surface, close to the real situation. Optical fibers with the diameter of 0,6 mm and 0,2 mm were used to guide a laser beam to teeth surfaces. Laser processing heads with lens F = 100 mm and F = 50 mm were used. The best samples were investigated by means of the Atomic Force Microscopy.

The blood sedimentation process is studied by means of the imaging system. This method allows to investigate the blood sediment behavior in whole sample. The blood was taken from healthy donors. From the normal and glutaraldehyde hardened erythrocytes the blood samples of three haematocrits (5%, 40%, 60%) in autologous plasma and dextran were prepared. Phases of the blood sediment that appear in the course of the process were recognized. We have shown that this method permits the analysis of traces of settling aggregates. Especially it is shown that the method can be useful in the study of the influence of cellular as well as plasmatic factors on erythrocyte aggregation and blood sedimentation.

The increase in inception rate connected with the cerebrospinal fluid have been observed recently. In the cerebrospinal fluid there are various types of suspension. There are cells and proteins which form different dispersion systems of given the sizes and concentrations among them. Finding out the physical processes occurring in the human cerebrospinal fluid is a problem of high importance. Coagulation, coalescence, aggregation and other physical processes in the cerebrospinal fluid depend on the state of health of the person who the sample was taken from. Thus it influences the concentration of suspension, its type and the sizes of suspended particles as well. In the paper the authors present the results of examinations of suspension in non-coloured human cerebrospinal fluid and the preliminary analysis of concentration of suspension and the sizes of suspended particles. The results were obtained by microscoping.

Camptothecins are fluorescent compounds which exhibit anticancer properties. A disadvantage which seriously limits application of camptothecins in antitumor chemotherapy is the hydrolysis of these compounds. They convert into inactive carboxylate forms. The process of hydrolysis is inhibited when the molecules of camptothecin are bound to cell membranes. So it is desirable that camptothecins molecules bind easily to membranes. A quantitative measure of drugs affinity to membranes is the association constant. To determine the association constant to membranes the lipid bilayers i.e. liposomes are used as model membranes. In this work affinity of hydroxycamptothecin DB-67 to model membranes is determined. Fluorescence spectra of this analogue change in presence of liposomes: the fluorescence intensity is bigger and besides green band the blue band appears. The spectra of hydroxycamptothecins change over lipids concentration. On the basis of this changes the association constant to membranes is calculated.

Erythrocyte deformability, known as ability of red blood cell (RBC) to change shape during flow in the microcirculation, is the basic rheological property of erythrocyte. Many techniques have been proposed to measure RBC's deformability (e.g. micropipette aspiration, micropore filtration, high shear viscometer and rheoscope techniques). Perhaps one of the most elegant technique for measurements of RBC deformability is ektacytometry, technique based on laser diffraction, worked out by Bessis and Mohandas¹ and recently developed by others^2,3. The laser light scattered by erythrocytes subjected to a well-defined shear stress (z) can be analyzed with the ektacytometer to obtain information regarding the changes in cell shape due to fluid shear. Usually, in order to deform RBC with shear stress the rotating Couette chamber is used ^1-5. From the diffraction images the elongation index (E), as a quotient of minor and major axes of the elliptically transformed diffraction patterns, is calculated. However, one has to face a series of methodological problems ⁵: 1. Occurrence of turbulences and heat shear, 2. Control of gap width within the Couette viscometer and the intensity of transmitted light, 3. The determination of RBC elongation coefficients E from the diffraction patterns. Therefore, in order to get accurate results, we have used unconventional technique which consists of a simple laminar flow system made from two parallel Plexiglas plates (flow-channel diffractometer) and the computer analysis of the diffraction pattern.

Determining the concentration of suspension in natural waters is one of the important problems of hydro-optics. The approximate method on the Mie theory using the parameters determined from measurements of the light attenuation coefficient in the investigated waters is discussed in the paper. The method was used to analyse spatial distribution of the volume concentration of suspension in the waters in the area of the Odra River mouth in Szczecin. The discussed method also gives correct results while considering waters of the Bay of Gdansk and southern Baltic Sea.

Campthothecin (CPT) and its analogues as prominent anticancer agents are currently the subject of the intensive studies. One of the most promising camptothecin analogues is 7-tert-butyldimethylsil- 1 0-hydroxycampthothecin called DB-67. It is characterized by high affinity to SUV (small unilamellar lipids vesicles) and relatively high stability in human blood. The studies of liposomal formulation as a delivery systems for DB-67 are the subject of this paper. The methods of dynamic light scattering (DLS), fluorescence microscopy (FM) and fluorescence spectroscopy (FS) are used to determine the physical properties of DB-67 liposomal formulation.

The idea of a substance with simultaneously negative values of dielectric permittivity ε and magnetic permeability μ presented by Veselago in 1968 has been brought to reality. Firstly, negative permittivity ε(ω) of a three dimensional photonic structure composed of thin metal wires was experimentally demonstrated in the GHz range. Secondly, a concept of split ring resonator has appeared and a structure composed of such metal resonators was shown to have negative permeability μ. Consequently, in a so called double negative, both ε(ω) and μ(ω) < 0, composite material made of cells consisting of a split ring resonator and a wire unnatural phenomenon of negative refraction was experimentally observed in the microwave spectral region. Recently, perfect lenses made of metamaterial with negative refraction index, photonic crystal or metal slabs were used to focus light below the diffraction limit of resolution. Electromagnetic transport of energy in plasmon waveguides made of subwavelength metallic elements offers a great potential value for nanoscale photonic devices of the future.

Photonic band gap materials are expected to play an important role in making devices in optoelectronics. Their main feature is that the diffraction of light occurs in a manner analogous to the diffraction of X-rays from ordinary crystals.. One class of such materials are synthetic opals. The 3D structure of synthetic opals consists of monodispersive particles of hydrated SiO₂ having diameter of the order of several hundred nanometers. A common way to produce an ordered structure is sedimentation. The method of Langmuir-Blodgett (LB) deposition has been used to obtain ordered structures and after some improvements samples of higher degree of order were made. The LB method using aNIMA alternate dipper made it possible to deposit up to 20 layers. Samples made by this method exhibit a domain structure visible to the naked eye. Domains exhibit a hexagonal symmetry and are of size ca 1 mm. The domain structure tends to disappear after the deposition of 5 or 6 layers. We studied layers obtained by scanning electron microscopy and studied their spectral characteristics. Reflectance spectra were measured for 1, 5, 10 and 20 layers. It was found that the main peak becomes sharper and more side maxima appear when the number of layers exceeds 8. Films formed from alternate layers of particles having different diameters are also discussed.

We propose two dimensional waveguide composed of silver rods in hexagonal lattice where coupling of surface plasmons is responsible for transport of energy. We examine guiding properties of this structure for lattice constant 200 nm, diameter of rods 100 nm and wavelength λ = 500 nm using Finite Difference Time Domain method. Electromagnetic wave is guided for transverse magnetic mode (light polarized perpendiculary to rods). Estimated attenuation factor is a = 5.63 dB/μm and group velocity of the signal is v_g=0.86 c. Interference pattern observed along the waveguide can be explained as standing wave created by reflection from edge of the structure. From period of this standing wave we calculate that phase velocity is v_p = (6.4 ± 0.1) c. Transverse electric mode when light is polarized parallel to rods is not guided in the structure.

Genetic Algorithm uses principles of evolution of organisms in nature to solve optimization problems. It is called 'genetic' because its operators are based on simplified concepts of population genetics. Evolution in the context of the numerical methods is represented by the evolution of artificial organisms whose genotypes encode possible solutions to the problem.

Optical methods are very powerful tools for non-destructive testing of works of art. There are several tasks connected with testing of works of art, which can be solved by use of optical methods, for example revealing of underdrawings in pictures, visualisation of artefacts that are due to degradation process invisible by naked eye, distinguishing between authentic and retouched parts of work of art, testing of degradation and ageing of works of art and many other tasks. In the contribution several selected optical testing methods will be described, among them ultraviolet fluorescence, infrared reflectography and laser scattering method.