We present a short overview of optical designs for projection systems to be used in Extreme UV lithography, a technique that is considered to be one of the potential successors to classical optical lithography. Typical state- of-the-art designs are presented with special emphasis on the peculiarities of ring-field projection systems. The specific properties of some new design developed by the present author will be discussed.

Intermodal dispersion in a two-mode optical fiber can be measured in the spectral domain when the spectral interference between modes at the output of the optical fiber shows up as a periodic modulation of the source spectrum that can be processed. However, this technique cannot be used to measure intermodal dispersion in the two- mode optical fiber when the period of modulation is too small to be resolved by a spectrometer. Consequently, we proposed a new measuring technique utilizing a tandem configuration of a dispersive Michelson interferometer and the two-mode optical fiber in which the spectral interference can be resolved even if a low-resolution spectrometer is used. In the tandem configuration of the Michelson interferometer and the two-mode optical fiber, the optical path difference (OPD) in the Michelson interferometer is adjusted close to the group OPD between modes of the optical fiber so that the low-frequency spectral modulation that can be processed is produced. Using the Fourier transform method in processing the measured spectral modulations and subtracting the effect of the dispersive Michelson interferometer, the feasibility of this technique has successfully been demonstrated in obtaining the intermodal dispersion in the two-model optical fiber.

IR imaging sensors are generally designed to be as sensitive as possible. This makes them vulnerable to dazzle and damage by attack from in-band lasers. An obvious method of protecting these sensors is to include rejection filters in the optical system. The required rejection ratio may be many orders of magnitude. Of particular interest is the possible application of rejection filters to protect thermal imagers. Some difficulties have been experienced in the laboratory measurement of the rejection ratio of such filters. These problems are explained and methods to overcome them are discussed so leading to a reliable method of measurement.

Low-coherence spectral interferometry can be used for dispersion characterizing two-beam interferometers or two- mode optical fibers when the spectral interference between beams or modes at the output of a dispersive interferometer or an optical fiber shows up as a periodic modulation of the source spectrum that can be processed. Thus, using the Fourier transform method in processing the measured spectral modulations, the wavelength dependences of the overall phases and then the first-order and the second-order dispersion characteristics, including the wavelength dependence of the group optical path differences (OPDs) between two beams in the dispersive interferometers or two modes in the optical fibers, can be obtained. The applications of low-coherence spectral interferometry can be extended to resolve the equalization wavelength at which the group OPD between two beams in a dispersive interferometer or two modes in an optical fiber is zero. The measurement of the equalization wavelength for the dispersive interferometer or the two-mode optical fiber, together with the measurement of the spectral dependence of the group OPD between two beams in the interferometer or two modes in the optical fiber, can be used for a compete dispersion characterizing the interferometer or the optical fiber.

The set-up of helium-neon lasers with internal iodine cells at the wavelength 612 nm was realized. Spectroscopical as well as metrological parameters have been measured using the third- and/or fifth- harmonic technique. The hyperfine structure of rot-vibrational lines R(47)9-2, P(48)11-3, R(48)15-5, and R(34)17-6 was detected also by the second harmonic method which enabled to find very weak peaks of cross-over components and read their frequency and amplitudes. The fundamental metrological parameters have been measured.

Due to inconstant velocity of movement of laser scanning beam in the plane of measuring as well as due to defocusing brought by the scanner there is possible the appearance of rather meaningful errors. Formulas and diagrams for these errors' calculations are derived.

An automated Fourier-transform method of phase retrieval of moire interferometric fringe pattern is presented. The method is shown to provide fast and accurate determination of the phase information by removing the carrier without shifting in frequency domain the filtered Fourier spectrum of the carrier-modulated moire fringe pattern. The principle of the method is described and moire interferometric measurements with submicron sensitivity of the in-plane displacement fields of thick carbon fiber/graphite-PEEK composite laminates are analyzed as example of application of the technique.

In this paper we describe an interferometric technique based on high precision 2D spatial fringe analysis Fourier method for measuring the elastic constant of nematic liquid crystals. Since the determination of the elastic anisotropy relies on the measurement of the ratios between the elastic constants, this technique provides a powerful and high accuracy method for characterizing nematic liquid crystals.

Magneto-optical (MO) Kerr effects are widely used for a thin film magnetism study. The otpical and MO properties of layer media are described through the permittivity tensor. A cubic crystal is optically isotropic and the linear MO effects are independent on the rotation of the crystal axes. On the contrary the MO effects quadratic in the magnetization are anisotropic in a medium with a cubic symmetry as well. In the paper, the anisotropy of the quadratic MO effects is discussed in the case when the magnetization lies in the plane of the layer. This configuration especially at a normal incidence is very suitable for the quadratic MO effects observations. The eigenmode equation is solved including both the linear and the quadratic terms in the permittivity tensor. The boundary conditions of the electric and magnetic fields at interface are described using 4 X 4 Yeh's matrices. The reflection coefficients form an interface between isotropic and MO media are derived including the quadratic MO terms. The quadratic MO effects observed through the conversion reflection coefficients and through the MO angles are dependent on the crystal axes orientations. The experimental measurements of the quadratic MO effects in reflection form an epitaxial bcc Fe layer are presented.

The merging of microwave and lightwave technologies has opened new opportunities in system design, especially in frequency standard generation and optical communication. Optical generation of microwave and millimeter-waves is usually carried out by coherent heterodyne together with some locking techniques to achieve a low phase noise. We present experimental results for an oscillator that converts continuous light energy from a semiconductor diode laser into radio frequency and microwave signals. Light from the laser diode is introduced into an electro-optic intensity modulator (EOM), the output of which is launched through an optical fiber delay line and then detected. The output of the photodetector is oscillation frequency limited by the sped of the optoelectronic components, a noise limit determined by the pump laser's RIN, frequency tuning capabilities, potential for optoelectronic integration. The present performance of our oscillator are: a power level higher than 20mW at 900 MHz, a free running spectral width below 1Hz and a spectral purity close to that of marked RF synthesizers.

We present a study for an easy-going and fast modal analysis. We tackle the problem with three different approaches: the first one adopts a finalist viewpoint and is based on the 3D finite Difference Beam Propagation Method along imaginary axis. The second one is the numerical analysis' classical finite element method, applied to H. The third one consists in amounting to slab waveguides for which there are analytical solutions. We emphasize on the distinct natures of errors and, as an illustration, we study one optical ridge waveguide and one buried waveguide, made up with polymers. The methods are computed on 200-MHz PC and we discuss calculation time and accuracy. Eventually, through the conception of a candid coupler, we demonstrate what it costs to choose the wrong way, and in view of typical parameters of these structure, which is the most suitable method.

An all-optical fiber device derived form the multiphoton absorption and erbium-doped fiber amplifier was demonstrated in erbium-doped fibers using 1510-1570 nm laser diodes. The reversed-phase waveforms were obtained in the transmitted laser at modulation degrees smaller than 87 percent and at modulation frequencies from 10 kHz to 1 GHz.

Lithium concentration depth profiles of proton exchanged (PE) and annealed proton exchanged (APE) lithium niobate optical waveguides were monitored by neutron depth profiling (NDP) for a large variety of the samples. Results of the measurements are related to the corresponding n_e depth profiles as measure by the standard prisms coupling method. It was found that c_Li depth profiles of the PE waveguides fabricated in X- and Z-cuts using the same fabrication conditions are almost identical indicating thus very similar extend of H⁺ $ARLR Li⁺ exchange reaction. The maximal depths of the exchanged layers were 3 micrometers . The following annealing causes a massive transport of lithium atoms towards the exchanged regions of the as- exchanged samples which is differs in the both types of the cuts. The Li-transport in the X-cuts seems to be hampered by a barrier formed by the larger amount of in-diffused interstitial hydrogen in the X-cuts, which results in a more-less step-like profiles of the X-cuts parameters. A formula relating n_c to C_Li values for the APE waveguides is also presented.

This study is focused on the low temperature plasma enhanced chemical vapor deposition technique used for fabrication of silica based optical waveguides on silicon, utilizing nitrous oxide as an oxidant for both silane and dopant. Fabricated channel waveguide shows total insertion loss of 1.2 dB at 1.55 micrometers , and no absorption peaks associated with N-H and Si-H bonds around 1.5 micrometers have been observed in the as deposited material. This fabrication technology adds flexibility to the monolithic integration of electronic and optical components. Using this technology, a n umber of different couplers based on multimode interference technique have been investigated.

The study of guided modes in planar thin film structures allows a precise characterization of the refractive index, the thickness, and the optical anisotropy. On the base of the matrix elements, the conditions for waveguiding in magneto-optical thin films at transversal geometry have been specified. In this case there are two independent dispersion relations for TE and TM guided modes. Usually we assume that the relative permeability is equal to 1 in the frame of optical frequencies. This approximation is problematic in far IR region and for ultrathin films in the optical one. For this reason the formulae of dispersion relations for guided modes in a monolayer system with both permittivity and permeability tensors have been derived. Various planar configurations are simulated. The permeability tensor effect at transversal magnetization in waveguiding structure is analyzed in detail. The experimental possibilities of the dark mode spectroscopy for permeability tensor study in mentioned structures are briefly discussed.

In most studies of 1D and 2D photonic crystals (PC) and photonic bandgap structures (PBG), the structures are considered to be invariant with respect to the remaining dimensions. If the PBG structure is to be incorporated into an optical waveguide, the inevitable refractive-index inhomogeneity used to create the waveguiding effect may detrimentally affect the behavior of the PBG. In this paper, such an influence is demonstrated by numerical modeling of a first-order waveguide Bragg Grating as a 1D PBG device. A condition for perfect spectral behavior of a waveguide PBG device is formulated and its validity is verified by numerical calculation of modal reflection and transmission spectra.

The Transparent Boundary Condition has been formulated for full wave equation and then embodied into propagation algorithm. The 'wide-angle' method using Pade approximation of Square Root operator was used for testing. The performance of new TBC is assessed based on reflection coefficient value and its dependence on propagation step- size and other parameters is investigated.

This article reviews in general terms the progress in the field of fiber Bragg gratings and specifically fiber grating related research carried out at the Institute of Optical Research (IOF). IOF has been involved in the field of fiber Bragg gratings since 1993, within both national and European projects.

It has been found that thin layers of aerogels applied by the sol-gel method on silica optical fibers change their optical properties due to the interaction with gases such as hydrocarbons. This paper deals with modification of the sensitivity and selectivity to vapors of hydrocarbons and chlorinated hydrocarbons of siloxane aerogel layers based on their doping with TiOTi chains and/or immobilizing in them Cu-ephedrine and Cu-phthalocyanine. The sensing fibers were prepared by the sol-gel application of porous siloxane and doped-siloxane layers on bare cores of PCS fibers. By using the excitation of the fiber with inclined laser beams it is experimentally shown that there are positive or negative changes of the output optical power from the fibers due to bringing the prepared layers into contact with vapors of aliphatic, aromatic and chlorinated hydrocarbons in nitrogen. These effects may be related to a difference between the refractive index of the layer and refractive index of liquid hydrocarbon or hydrocarbon its derivative. It is shown experimentally that doping porous siloxane layers with copper complexes changes their refractive index and optical losses changing thus their sensitivity and selectivity to hydrocarbons and hydrocarbon derivatives.

Multimode optical fibers with inverted parabolic refractive- index profiles (IGI fibers) have been shown promising for the fabrication of sensing modules for evanescent-wave chemical detection. Besides IGI fibers with parabolic index profiles, this paper deals with theoretical and experimental investigation of some other types of IGI fibers, particularly with IGI fibers with linear and modified-linear profiles. Refractive-index profiles of the fabricated IGI preforms doped in the core with boron oxide are shown in the paper. The sensitivity of IGI fibers drawn from these preforms to cladding refractive-index changes has been studied by means of the technique of selective excitation of optical models in the fiber immersed in various mixtures of n-butanol and benzyl alcohol. The obtained results are compared with those for reference step-index fibers with uniform pure-silica core. A theoretical model describing the detection process during these measurements has been derived using geometrical optics. On this basis it can be shown that the fiber sensitivity increases in the order of the reference fiber, IGI fiber with linear and modified-linear profiles and IGI fibers with parabolic profiles.

The influence of reciprocal and non-reciprocal perturbations such as magnetic fields, strain, twist and bending on the eigenfrequency bandstructure in a gyroscope, based on a fiber optic Sagnac interferometer have been determined and discussed.

We present a surface plasmon resonance sensor base on prism excitation of surface plasmons and spectral interrogation. For specific detection of biomolecular analytes, multilayers of monoclonal antibodies are immobilized on the surface of the sensor. Detection of biomolecular analytes such as human (beta) -2)-microglobulin, choriogonadotropin, hepatitis B surface antigen, salmonella enteritidis is demonstrated.

Real-time, in-situ monitoring for quality control of the polymer cure process is of high interest. In this paper, we suggest to study a fiber-optic cure sensor. This sensor is based on the measurement of angular distribution of light transmitted through an optical fiber inside the cured polymer.

The aim of this paper is contribution to understanding of coupling between the polarization modes on the resultant transfer properties of single mode fiber given by the Jones matrix. In the case of ideal fiber it is possible to describe a propagation of the polarized optical wave by the Jones matrix and corresponding polarization eigenmodes with different propagation described by the Jones matrix are given not by the eigenmodes but by the principal states of polarization. Defined disturbance by the Jones matrix are given not by the eigenmodes but by the principal states of polarization. Defined disturbance along the whole fiber and also relatively defined variable coupling between the polarization modes it is possible to obtain by the torsion of fiber. Experimental evaluation of torsion effect by the Jones matrix elements can define the boundaries of application theory of polarization eigenmodes and principal states of polarization. These results can also contribute to understanding of conditions for polarization preserving of fiber and the development of polarization dispersion during disturbance of propagation conditions. Jones matrix elements have been measured on the working place published before and calculation and optimization of result are done by the use of software made for this purpose with the application of quaternions.

The influence of the intrinsic linear birefringence and/or the external reciprocal perturbations on the free spectral range of a reflective fiber Fabry-Perot, for magnetic field sensing, with a conventional or a Faraday rotator mirror, are analyzed and discussed. By means of the calculation of the eigenvectors and their eigenvalues, the optical frequencies of such sensor, are evaluated. Results show an improvement in the finesse of the resonator respect the transmissive configuration.

We report a new optical sensor based on excitation of a surface plasmon in an optical fiber Bragg grating (FBG) structure. The sensing device consists of a side-polished single-mode optical fiber with a Bragg grating written into a fiber core and a thin gold overlayer supporting SP. If a coupling between a guided mode of the optical fiber and a SP mode is established, any change in the refractive index of analyte affects propagation constant of the fiber mode producing a change in the amount of light reflected by the FBG. A laboratory prototype of the sensor has been developed and its potential for refractometry has been examined. It has been demonstrated that the sensor's sensitivity to refractive index is as high as 750 dB/RIU.

Due mainly to explosive growth of data transmission fueled primarily by rapidly increasing number of ever more powerful personal computers and servers and unprecedented popularity of mobile communications, there is great pressure on network operators to keep pace with these developments by increasing throughput of their networks. This is determined by transmission capacity of access as well as inter-nodal links and by switching capabilities of the network nodes. The ultimate objective is to have latency free network able to support real time traffic as well as near real-time data communications utilizing, for example Internet Protocol. Equipment vendors and network operators are meeting these demands by their efforts to fully exploit the potential of photonic technologies both in transmission as well as in processing of signals in optical domain. State of the art in the field of photonic networks is described.

If two patterns are combined with each other they create a pattern of their own. Interference between two sets of fine pattern grids, the scanner samples and the geometric structure in the original image cause moire patterns. These artifacts are generally accepted as an inevitable quality degradation of the screening process. In this paper two patterns were combined to provide a moire- the first one with RGB sensor, the second one with the RG-BG sensors, both with the Siemens' star.

Two optoelectronic integrated circuits (OEICs) are presented: a current mirror amplifier for low-offset DVD OEICs and a high-speed amplifier for optical data transmission and optical interconnects. Both OEICs were integrated with PIN photodiodes in a standard 1 micrometers CMOS process on epitaxial wafers. For the DVD OEIC -3 dB- frequencies in excess of 30 MHz and for the high-speed receiver a NRZ data rate of 622 Mbit/s are achieved.

This article deals with the using of an optical CATV network for a transmission of multimedia signal to subscribers. A CATV network consists of passive optical network with a tree and branch topology. For a transfer of digital signals is employing the ATM transfer mode.

This article describes information network - a backbone network structure, a video switch topology and acousto- optics processor applications - AOP. Cable is a natural network for carrying high-capacity, bandwidth - in tensity information. In the age of analog program signals, cable capacity was a natural transmission media for broadcasting of color TV and high-fidelity stereo sound programs. In the new digital program signal age, cable high capacity is a natural network for carrying interactive computer-based, data-multimedia programs.

Helical wavefronts can be created by transmission of coherent waves through spiral phase filters. This kind of wavefronts has in the center of a helicoid a singular point called an optical vortex in optics. According to the number m of transitions of the wavefronts through the plane perpendicular to the direction of propagation in the full angel 360 degrees C the vortex is called m-charged. A usual approach supposes for the final step an integer multiple of wavelengths which fits into the whole path difference. This contribution analyses the case when this proposition is not fulfilled and the final step is not an integer multiple of wavelength. The wave amplitude in the optical vortex is computed as an integral of phases of all nearest rays around the singular point.

We report on the measurement of the time relaxation of the electro-optic properties of poled side-chin copolymers under illumination with absorbed laser radiation. Films of side- chain Disperse Red 1 substituted poly-Methyl-Methacrylate were sandwiched between ITO and gold electrodes and poled with a standard temperature/electric field cycle. The decay of the electro-optic properties, measured by means of the Teng and Man ellipsometric reflection technique at (lambda) equals 830nm, was measured for several intensities of a circular polarized absorbed laser beam, (lambda) equals 514.5nm, illuminating the sample. The relaxation shows a stretched exponential time dependence, with intensity dependent decay and stretching constants. The relaxation curves are compared with those obtained, for the same sample, in standard temperature stimulated non linear dielectric relaxation measurements.

A wide range of photonic guided-wave devices may be modeled by using rigorous numerical approaches based on the finite element method (FEM). In this work, representative modal solutions for linear, nonlinear, anisotropic, passive and active waveguides are discussed. Photonic devices incorporating several butt-coupled uniform waveguide sections, such as optical modulators, switches, filters, polarizers and spot-size converters are analyzed by using a combination of the least squares boundary residual method and the FEM.

THe paper presents the analysis of the Optical Coherence- Domain Reflectometer with the Synchronized Coherence Function (OCDR-SCF). A brief summary of up-to-date approaches to the optical reflectometry is given. The fundamental equation of the OCDR-SCF is derived and a general approach to the synthesis of coherence function with arbitrary shape is described. The synthesis of the (delta) - like shape coherence function is illustrated. The mean performance parameters and the application of the OFDR-SCF are discussed.

The optoelectronical systems with image intensifier tubes (IIT) have today various applications, in different fields: military, industrial or scientific. The variety and complexity of IIT systems applications demand a realistic selection of components and a well-oriented design, on the base of mathematical analysis. This paper presents our theoretical and experimental efforts to find a model for the design of night vision goggles, with the accent to the objective lens, not rarely the most neglected components. We calculate the requested MTF for the objective lens starting from the desired observation range in well establish conditions, the image intensifier tube used in the application and the target configuration. This is possible if were consider the signal to noise ratio as detection criteria in an optoelectronic-generated image. The field and laboratory experiments demonstrate the viability of the theoretical assumptions and relations. In this way, the optical design of this kind of devices may be developed in a controlled way, without useless efforts and costs, with the certitude that the required performances are obtained.

New results on the studied of photo- and electron beam induced changes in solubility of amorphous As-S-Se and As₂S₃ thin films are reviewed. It is shown that amorphous chalcogenide semiconductor resist can be applied in holography and the fabrication of diffractive optical elements by electron beam lithography is possible.

An analytical mathematical model of the heterojunction photodiode is presented. The modified formula for the thermionic emission current at the abrupt heterojunction is used. Steady state photodiode parameters and the current frequency response to a small optical modulating signal are calculated. Derived general formulae are applied to the N- AlGaAs/p⁺-GaAs heterojunction.

Using the scattering matrices and the graph theory, three basic structures of all-fiber interferometers, Mach-Zehnder, Michelson, and Sagnac have been analyzed. The influences that, the couplers with losses and constant coupling polarization dependent, and the birefringent of the optical fibers, both used for making these optical systems, introduce in the performances of the three interferometers, are studied and compared.

We present the following results. Using an e-beam lithography we fabricate don a quartz substrate binary DOEs for the effective formation of individual Gauss-Hermite modes, (1,0), (1,1), (1,2) and (7,0). The transmission function of such DOEs is found to equal the signum function of the Hermite polynomial. Numerical simulation has shown that the binary signum DOEs are capable of generating first GH modes with a 64-72 percent efficiency. In real experiments such DOEs operate in agreement with theory and with satisfactory efficiency.

Holographic surface-relief diffractive elements with an inclined profile working as transmission grating couplers for backplane interconnects were fabricated and their diffraction efficiency was measured during a step-by-step development process for various orientations with respect to the direction of incident light. The highest diffraction efficiency was achieved for p-polarized light which propagates inside a medium of lower optical density and is outcoupled into a medium of higher optical density.

In this paper, numerical result of simulating various linear and nonlinear photonic devices using the finite element based-vector and scalar beam propagation methods are presented. The application of this newly-developed vector finite element based beam propagation method to problems involving radiation losses, like leaky-mode and bent optical waveguide devices is shown, and a study of a novel arrangement invovling three-coupled cores working as a polarization-insensitive optical filter is demonstrated. Also, scalar BPM algorithms based on finite elements have been developed and applied to nonlinear problems, like second harmonic generation and soliton switching in nonlinear fiber couplers.

Novel principles of design of a diode-pumped solid-state laser with scalable average output power are described. The approach is based on a double waveguide slab (DWS) concept, when laser slab has a waveguide equality both for pump and laser radiation propagation in the orthogonal directions. The advantages of such a scheme are efficient conduction- cooling and scalability of a laser head to the kW range with the high quality of a laser beam. The feasibility of this concept was proved with the model of a DWS Nd:YAG laser at the level of average output power of 10W. The promising possibility to use thermally strengthened Nd-glass for a high average power qcw laser is discussed.

Novel technique for the efficient remote sensing of speckle- pattern displacements is proposed. It is based on the polarization self-modulation effect recently discovered in photorefractive crystals. The technique provides linear responses on the amplitude of the lateral displacement and high sensitivity which is comparable with the interferometric one. Both sensitivity and dynamic range of measurements can be adjusted varying the average speckle size on the input face of crystal. The simple and inexpensive experimental set-up does not include any reference or read-out beam. Proposed technique can be applied for optical measurements of the transient motion of inspected surface such as object's vibration monitoring.

The performance of W/Pt/doping element/Pd and Pt/doping element/Pd ohmic contacts has been investigated, where Ge, Si, and Sn were employed as doping elements. The contacts were deposited by vacuum sputtering on n⁺-GaAs substrate plates and GaAs or AlGaAs epitaxial layers, then annealed by a power YAG:Nd laser. The influence of the doping elements on the parameters for ohmic contacts was not significant, with germanium being the best, we obtained a minimum value of r_c equals 5 X 10^-6 (Omega) cm². The layers of GaAs and AlGaAs were prepared with (delta) -doping by MOVPE epitaxial growth method. The minimal values of contact resistivities of 1.1 X 10^-4 (Omega) cm² and 7.35 X (Omega) cm² were achieved.

A tunable solid state laser system has been developed emitting visible light in the region from 710 to 775 nm, which can be used for medical applications. The laser head of this system is composed of alexandrite crystal rod, two dielectric mirrors, and a tuning element. The maximum reached output energy in the free running multimode regime was 400 mJ with the pulse duration of 70 micrometers . The output laser radiation was guided via a multimode quartz fiber or via a special fluorocarbon polymer-coated silver hollow glass waveguide. At first, this radiation with laser fluency of 2.5 J/cm² was used for the ablation of dental calculus. Next, the laser radiation propagation in the root canal and its effect on bacteria was proved. The dissipated energy measurement was made inside and outside the tooth. Hence, the alexandrite laser could be useful for medical applications in dentistry.

Er:YAG laser system generating radiation in a free-running, long-pulse mode regime with the output energy up to 610 mJ and the wavelength in the mid-IR region was designed. As delivery systems, a fluorocarbon polymer-coated and a cyclic olefin polymer-coated silver hollow glass waveguides were used and the comparison of the radiation transmissions of these two waveguides and the articulated arm delivery system was made. ALl the delivery systems were ended by the focusing optics or by a special sapphire tip, for a non- contact and a contact treatment in the real applications, respectively. The output energy from these systems was in the range from 100 mJ up to 450 mJ. In the applications, the laser radiation was directed at a dental or an eye tissue. In the dental procedure, the differences between the contact and non-contact Er:YAG laser hard dental tissue preparation and also between the delivery system - articulated arm and waveguide-were verified. The influence of laser energy and number of pulses on profile and depth of drilled cavity was investigated. In the ophthalmologic surgery the contact and non-contact laser-phacoablation was investigated. The result show that the Er:YAG laser system could be a useful instrument in ophthalmology and dentistry.

Methods for the characterization and a numerical model of Er³⁺/Yb³⁺ codoped fibers for power fiber amplifiers and lasers are presented. The main goal of the developed model is to predict gain characteristics of an actual Er³⁺/Yb³⁺ fiber in the large-signal regime of operation. The numerical model is based on an iterative solution of the fiber propagation and the laser rate equations. The parameters of doping are obtained from the measurements of the saturation of absorption at a specific wavelength in the Er³⁺/Yb³⁺ doped fiber by fitting the measured curves of the absorption saturation using the developed theoretical model. For the parameters obtained, the numerical simulations of the gain are compared with the measured gain.

Seeded Q-switched pulsing in a diode-pumped Er-Yb glass laser has been experimentally demonstrated. The Q-switch is a beta-barium borate Pockels cell. The voltage applied to the BBO is much lower than the voltage needed to hold off the laser. This allows low-power, free-running lasing to seed the Q-switched laser-pulse. Q-switched operation is accomplished with a reduction by a facto of 5 to 8 below the full hold-off voltage. Measurements on this system also allows an estimation of the time of the energy transfer between Yb and Er ions.

Topological structure of the mathematical models of the laser diode amplifier (LDA) can be visualized with the help of a diagrammatic method based on depicting differential relationships of the form (delta) y equals t_xy(delta) x by the diagram x yields y. The quantity t_xy is called the transmission function of the oriented line xy. Such atomic diagrams can be combined to more involved schemes to represent systems of mathematic formulas. The approach is demonstrated on the LDA model proposed by Adams. The diagram representing this model is derived and shown to contain two closed oriented paths - feedback loops. The transmission function of these loops are shown to have a controlling influence on the qualitative operation mode of the LDA. In particular, if their sum crosses the unity level in two distinct states, the LDA acts as a bistable element. This condition can be expressed in terms of the numeric values of the characteristics parameters such as the driving electric current, facet reflectivities, resonator length, etc.

A linear stability analysis of the laser-Lorentz equations taking into account local field correction is presented. It is demonstrated that this correction lowers the instability threshold for negative detunings. In addition, we determine the criteria for which the instability occurs.

In this article we describe a system which enables creation of several optical traps by splitting the laser beam in two parts and by using an acoustooptical deflector in one of these parts. This system is combined with a UV pulse laser so that a complex apparatus for optical trapping and cutting is obtained. Movable lenses ensure independent 3D positioning of a beam focus of the trapping and cutting beam without power losses at the back objective aperture. We present several applications of this system.

An experimental method for the measurement of the profile of the laser beam focused by a high NA lens is presented. A homemade PZT driven stage is used to scan a near-field optical microscope probe through the beam profile. The probe position is detected via strain gauges which were calibrated by laser interferometer and the intensity collected by the probe is measured by photomultiplier. The stage positioning accuracy +/- 50 nm enables the measurement of the intensity distributions within submicron-sized beam spots. As an example, intensity profiles of a TEM₀₀ laser beam focused by a water immersion objective are presented.

We propose and demonstrate experimentally that an Er-doped twin-core fiber (ErTCF) can be employed as a tracking narrow-band filter in tunable fiber ring lasers for line narrowing and wavelength stabilization. The partial separation of the light paths for different wavelengths in the ErTCF coupler mimics the saturable absorption with inhomogeneous broadening. The slow erbium ion saturation dynamics prevents wavelength hopping while it enables the filter to track the operation wavelength when the laser is tuned. The operation of the deice is improved by utilizing the inherent filtering effect of a twin-core coupler.

Thin active layers of chemical sensor were deposited form tin dioxide targets by the pulsed laser deposition (PLD) method. The deposition was made by employing excimer KrF laser. The bearing part of the senor is an alumina chip provided by Pt-electrodes in the interdigital configuration. They serve for reading of the sensor response - DC resistance of active layer. Under reducing gases the resistance of the active layer decreases. For the stabilization of sensor properties it is necessary to use dopants. In this case the PLD technology enables an original solution-introduction of dopants as a multilayered structure. In order to improve the sensor parameters, catalytic Pt or Pd is vaporized to the surface of active layer in the form of non-aggregated particles.

In this paper we have studied the performance of Pt/Sn/Pd contact structures on n+)-GaAs plates. An absorbing cap layer is necessary to use in the case of a laser annealing. Pt layer deposited by sputtering with the thickness of 12 nm gives the best parameters. The semiconductors plates were cleaned prior the deposition of metallization by various solutions, the lowest contact resistance was obtained in the case of H₂O₂:NH₄OH:H₂O. The laser annealing was compared with RTA method, which was not suitable for this contact structure.

We describe an interferometric technique based on temperature dependent optical path length changes in thin slab of transparent materials, suitable for measuring the thermo-optic coefficients of transparent materials. This technique allows an accurate determination of the fringe shift corresponding to a change in the sample temperature, by means of a two fringe pattern Fourier-transform based processing algorithm for phase retrieval. The principle of measurement of the method and its applications to the measurements of the thermo-optic coefficients of some commercial glasses are presented and discussed.

The analytical model of intracavity frequency doubled end pumped laser has ben worked out and applied to optimize the major components of such laser. The experiments of cw and passively Q-switched intracavity doubled Nd lasers were carried out. About 1 W of averaged green power, with pulse energy of 150 (mu) J, pulse duration of 40 ns were achieved for 10 W fiber coupled pumping diode. The directions of optimization of such lasers were formulated.

We describe in this article a system that automatically finds the maximum output power of a metal vapor laser by means of temperature control of the laser heating system. Metal vapor lasers use a heater in order to attain the required operating temperature. Heating is obtained by the laser discharge itself, or with an externally heater system. The temperature of the metal vapor laser is very critical and requires temperature control. When the developed system associated with the typical regulating system to obtain maximum output power. The design is based on the automatic temperature control of the regulating system reference in order to optimize the output laser power. This system can be used with any pulsed laser dealing with a heater.

In pulsed gas lasers, the excitation of the active medium is produced through the discharge of a storage capacitor. Performances of these lasers were essentially linked to the type of switch used and also to its mode of operation. Thyratrons are the most common switches. Nevertheless, their technological limitations do not allow a high repetition rate, necessary for optimization of the output power of this type of laser. These limitations can be surpassed by combining the thyratron to a one stage of a magnetic pulse compression circuit. The mpc driver can improve the laser excitation pulse rise time and increase the repetition rate, increasing the laser output power of pulsed gas laser such as; nitrogen, excimer and copper vapor lasers. We have proposed in this paper a new configuration of magnetic pulse compression, the magnetic switch is place in our case in the charge circuit, and while in the typical utilization of magnetic pulse compression, it is placed in the discharge circuit. In this paper, we are more particularly interested in the design and the modeling of a saturate inductance that represents the magnetic switch in the proposed configuration of a thyratron - mpc circuit combination.

Cr⁴⁺:YAG crystal is a solid state laser active material broadly tunable in the near IR spectral region which makes it attractive for applications in optical fiber communications, laser remote sensing, eye-safe ranging and numerous other uses. In Cr:YAG laser crystal which is a low gain active medium the saturation of absorption of pump radiation has a significant role as the decreasing absorption with increasing pump power leads also to saturation of output power.In this paper we studied this effect and we report on absorption and laser characteristics of two Cr:YAG crystals with different chromium concentration and crystal preparation. The laser performances are compared under excitation from arc lamp-pumped Nd:YAG laser with maximum output power of 10W in four mirror and three mirror astigmatically compensated resonators.

The concept of resonant carrier many body interaction during radiative recombination was applied to explain spectra of quantum well electroluminescence at 77 K. Extremely good agreement of the calculated and experimental spectra in the entire range of emission has been achieved. Estimations give a sub-picosecond characteristic time of such radiation process.

Large numerical aperture telescope with nonlinear optical correction for distortions, designed for the remote self- luminous object imaging, was realized in experiment and investigated. Dynamic hologram, recorded in optically addressed liquid crystal spatial high modulator, was used as the corrector. Nearly diffraction limited performance of the system was demonstrated.

This contribution concentrates on theoretical studies of diffraction processes in surface-relief gratings. The characterization of diffraction processes and mechanisms is presented and discussed, together with the regions with typical diffraction regimes. The attention is also devoted to phase synchronism: angular and volume types of synchronisms are distinguished. Some typical examples of modeling are considered for a class of binary surface-relief gratings. Rigorous coupled-wave analysis is used for modeling, and some interesting result of volume phase synchronism are presented and discussed. Finally, features of a fundamental resonator region, which is characterized by strong energy interchange processes, since a new diffraction order starts to become real propagating, are described and interpreted.

THe generalized computer model (GCM) has been developed as a tool to be use din electro-optical system (EOS) designing and prediction of their quality. Descriptions of radiators, environment and atmosphere submodels as well as EOS structure and figures of merit are parts of the model. The model is integrated software package for designing and parameter optimization of EOS. Five main steps of the model utilization in designing EOS are indicated.

Two-wavelength interferometry technique provides accurate measurement of geometric values in extended range of measurement definition. We propose the approach to two- wavelength interferometric signal processing based on recurrence data filtering. Interferometer is illuminated by monochromatic light source on two wavelength simultaneously. The position of reference mirror is changed step by step inside the range defined by 'synthesized' wavelength. It is used the recurrence least-square fitting algorithm to estimate the two-wavelength interferometric signal parameters dynamically taking into account the particularities of the signal model. To suppress the background and noise influence the discrete recurrence filters with linear phase characteristics have been used.

Spatial solitons in cavities are being investigated with a view to applications in parallel information processing. This paper discusses the nature, experimental demonstration, and control of spatial solitons in cavities. Properties of interest for information processing are identified.

Two-wave mixing in photorefractive InP:Fe crystals is revisited considering an externally applied dc field combined with the moving grating technique. We show that the disagreement previously observed in the literature between theory and experiments finds an explanation in the influence of both the absorption along the propagation axis and the nonlinearities occurring at relatively large fringe modulations. A finite difference method is used to demonstrate the dependence of these nonlinearities on the average incident intensity.

Our main interest is to establish connections between Optics and Fuzzy Set Theory. We formulate the t-norms based algebraic description of both geometrical and Fourier- approximations of optics. Geometrical optics implements probabilistic operators under the linear approximation of negative recording process. For real recording media not Zadeh's, but Sugeno negation is more appropriate approximation. It gives dual to the product t-norm family of t-conforms, parameterized by the recording medium and developing process properties. Fourier-optics allows Fourier-duality to be used in addition to N-duality. Fourier-holography setup implements semiring with product t- norm and F-dual family of t-conorms - sum-product convolutions, parameterized by holographic recording medium operator. Implication operator, implemented by Fourier- holography technique, is defined. Experimental realization of General Modus Ponenes rule by holographic fuzzy interference engine is presented.

Recently the photometric and spectrophotometric methods of biotissue diagnostics, based on searching interrelation of scalar characteristics of optical radiation field with their structural parameters. The complex of investigation of transformation processes of linear-polarized radiation in biotissues has demonstrated the new possibilities of diagnostics of their pathological biotissues. The report presents deals with researching possibilities of laser polarized diagnostics of arising and proceeding of pathological changes of biotissues morphological structure.

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

The phase-polarized method of visualization of optical- anisotropy inhomogeneities of biotissues is proposed. It is based on the multifractal modeling of biotissue properties. The algorithm of receiving topograms of orientation of fractal domains of visualized architectonic net of a biotissue is elaborated and approbed experimentally.

The contribution is to present both theoretically and experimentally a possibility to change the state of polarization of polarized light by means of holographic grating. A He-Ne laser and holographic plates had been used in our experiment. The result obtained allow us to suggest a polarizing element, which makes use of a transmission type diffraction grating.

The hybrid optical-digital two-stage joint transform correlator (JTC) experimental setup was created. The transformed phase mask (PM) was used as an optical mark to be identified in the hybrid JTC. The minimum possible focal length of a Fourier lens in the joint Fourier transform processor of the hybrid JTC first stage was defined and optical schemes were calculated and designed. The procedure of the transformed PM identification in the hybrid JTC was represented. Performance of transformed PMs in different modifications of the experimental setup was studied. The peak-to-noise ratio (PNR) for each correlation peak in the firs diffraction order of the output correlation signal was calculated. The dependencies PNR versus effective focal length were analyzed.

The impact of a two level ultracold ion vibrations on its spontaneous emission in a single resonance mode microcavity has been analyzed nonperturbatively. The 'recoiless' emission of photon by the moving ion has been revealed. The resonance exchange with energy through the AC Stark- sublevels of the 'ion + cavity mode'-subsystem has been pointed out as one of effective mechanism enhancing greatly energy transform from spontaneous radiation to vibrations.

We have observed SRWS without phase modulation and self focusing of the pump beam with use of a Bessel beam excitation. The experiments show at the scattering threshold two types of line spectra, and above the threshold a large band spectrum. These results are interpreted by the presence of four photon processes coupling two exciting photons, one Stokes and one anti-Stokes scattered photon, developing in cascade. This interpretation can be extended to the recent studies of soliton propagation in a planar waveguide.

We synthesized some novel rigid NLO-active maleimide copolymers bearing DR-1 moieties (PMPD, PHSD, and PHND). All copolymers exhibited high Tgs and good solubilities for common solvents and excellent film-forming properties. Dependence of film thickness on the d₃₃ value for the poled copolymers induced by corona poling was investigated and it was demonstrated that from less than thickness of 0.3 micrometers decrease of the thickness gives rise to remarkable increase in the d₃₃ value. The poled copolymers exhibited large d₃₃ value for PMPD, 290 X 10^-9 esu for PHSD and 350 X 10^-9 esu as well as large r₃₃ values. The d₃₃ values of the poled copolymers were kept constant even after standing 1000 h at 80 degrees C, although a small decrease was observed at a very initial state. Further, the d₃₃ values did not change up to ca. 123 degrees C upon heating at the rate of 10 degrees C/min in all cases.

Stimulated Raman scattering of picosecond pulses was investigated in gaseous methane and KGd(WO₄)₂ crystal. As a pump source, we used the second harmonic output of a mode-locked Nd:YAG laser system. Pulses of energies up to 20 mJ at 532 nm were used; the pulse length was equal to 41 ps. During the experiment, we measured the characteristics of scattered radiation in each nonlinear material. For gaseous methane at 1 MPa, the threshold pumping intensity was measured to be 110 GW/cm². The first Stokes component and the anti-Stokes lines to the third order were detected. The overall conversion efficiency of 46 percent was obtained. The measured threshold intensity is in good agreement with the transient SRS theory for this medium. The threshold pumping intensity for KGW crystal was measured to be 600 MW/cm². The Stokes components to the third order were observed with the overall conversion efficiency of 50 percent. The SRS gain coefficient of 24 cm/GW was calculated from the obtained results. Comparison of the two investigated materials favors the crystalline Raman shifter because of lower SRS threshold intensity, higher gain, and god mechanical properties.

We consider the dynamics of a nonlinear Fabry-Perot interferometer symmetrically pumped by two light beam. An analysis of the conditions for realization of symmetric and asymmetric modes of optical bi- and multistability has been performed using a theory of degenerate four-wave mixing adapted to a Fabry-Perot resonator with amplitude-phase nonlinearity. Complexity of the dynamic behavior due to symmetry breaking bifurcations has been investigated both theoretically and numerically.

The schemes of light beam transformations by volume dynamic holograms in resonant media revealing the fifth- or higher- order nonlinearities have been theoretically analyzed. N- wave mixing has been realized by changing of the propagation direction or read-out wave frequency in the solution of Rhodamine-6J dye and polymethine dye 3274U. It has been demonstrated that the experimental result are in good agreement with the theoretical data obtained for a three- level medium model with due regard to absorption form the excited singlet level.

Room temperature visible photoluminescence (PL) and electroluminescence (EL) of wide band gap hydrogenated amorphous silicon thin films prepared in SiH₄ microwave plasma strongly diluted with He is reported. The emission spectra are peaked at approximately 1.5 eV. Films were characterized by means of optical and IR absorption and hydrogen thermal desorption. The band gap of a-Si:H films varies within the interval 2.0-2.2 eV. The strong evidence for two distinct types of PL processes is presented: one being linked with oligosilanes and the second one attributed to electron-hole recombination in tail states. EL has been investigated in p-i-n and p⁺-p-n-n⁺ structures with CrNi/ITO contacts. The EL occurs after initial forming in reverse bias only and its external quantum efficiency is approximately 10^-5 percent. The shape and spectral position of EL spectra suggest that the light emission in this case is probably due to simultaneous excitation of the oligosilane units and impact ionization by hot electrons.

Sulphide glasses of GeGaS and GeGaAsS systems doped with rare earth ions are promising materials for various photonic applications. Because the solubility of rare earth elements ins influenced by the purity of host glass, namely by OH group concentration, the attention has been paid to the preparation of highly pure and homogeneous undoped and rare earth doped glasses. Particularly the systems Ge_0.25Ga_0.1-xS_0.65Pr_x and Ge_0.25Ga_{0.05- x}As_0.05S_0.65Pr_x with x equals 500, 1000, 3000, 6000 wt. ppm have been prepared. Synthesized materials system have been characterized by Raman and low-temperature photoluminescence spectroscopies. The optical Pr concentration has been found to be around 1000 wt.ppm. The appearance of temperature induced radiative transitions have been observed on GeGaS:Er samples.

The peculiarities of the photon echo excitation by two non- collinear pulses in optically dense media with extreme inhomogeneous broadening are investigated theoretically and numerically. Non-linear pulse evolution during propagation is taken into account. Red frequency shift of the primary photon echo signal is predicted. The influence of pulse transformation on the echo time delay is analyzed.

A great variety of methods for network analysis have been developed both in the frequency domain and in the time domain. The analysis methods in the frequency domain are applicable both to coherent sources as in incoherent sources and they also make the analysis of the most complex structures possible. In this communication several matricial methods in the frequency domain, such as the scattering matrix in conjunction with the graph theory, the Yeh 4 X 4 matrices, and the transfer matrices are introduced and compared. They permit the exact and systematic analysis of the birefringent bi-directional concatenated photonic two- port and four-port networks. This analysis technique has been applied to the design and simulation of the polarization-based in-line wavelength filters made by directional couplers and hi-bi optical fibers, such as all- fiber Fabry-Perot resonators, and Lyot-Ohman, Solc-fan, and Solc-folded all-fiber filters. The use of these matricial analysis methods gives the precise optical spectral response.

The article is devoted to the development of technical university course in photonics. The work has been done and the results are two grants from the Czech Ministry of Education and it has covered all three parts of study - BSc course, MSc course and PhD course. The structure of existing subjects was overviewed and the new system has been created. A different approach has been implemented in the PhD course where the extensive participation of students in R and D has been essential.

A computer controlled color discrimination test is described which enables rapid testing using selected colors from the color space of normal CRT monitors. We have investigated whether difference sin color discrimination between groups of normal and color deficient observers could be detected using a computer-controlled test of color vision. The test accurately identified the differences between the normal and color deficient groups. New color discrimination test have been developed to more efficiently evaluate color vision.

It is important to train skill of realizing main optical and electro-optical principles. In the Moscow State University of Geodesy and Cathography the modulus sets of typical optical, opto-mechanical and electro-optical blocks have been worked out toward this end. The modulus sets make it possible for designing many optical and electro-optical devices and processes as well as for creating metrological stands for investigation of these devices.

Diffractive optics makes use of diffraction of light to design otpical elements and systems, which serve for imaging visual objects and transforming coherent optical beams. A diffractive structure can be computed and the pattern written using focused laser or electron beams. Phase nature of diffraction pattern is preferred. Computations involve the first and second order terms and a curvature of the substrate plate, which can be exploited for the element to be aplanatic. Diffraction grooves should have a suitable transversal saw-tooth profile to obtain the highest diffraction efficiency. An alternative method for fabrication of elements of this kind is holographic recording, which can be use mainly for off-axial components.

Although the mechanism of heat transport is a typical diffusion process, in cases in which the heat source is of a sinusoidal type, it may be found convenient to transform the Fourier diffusion equation in a formal Helmolz equation, speaking of thermal waves. In the present paper we will use this formalism for handling data from a photothermal measurement to retrieve the profile of thermal diffusivity under the surface of a solid material, showing that the surface temperature field obtained by the photothermal method can be connected to the thermal properties of the material in a simple and elegant way by using the concept of thermal waves scattering by the small thermal inhomogeneities of the material.