Search

It is shown that laser modification of a nanometer titanium film can be used for precise control of the loss level in optical waveguides on lithium niobate substrates. Theoretical estimates of the change in linear losses at the level of 0.95 dB/mm were confirmed by experiments on local laser modification using radiation at a wavelength of 976 nm with a threshold intensity of 1 kW/mm2. The proposed method can be effectively used for precision adjustment of the characteristics of integrated optical devices, such as the modulation contrast of Mach–Zehnder modulators.

The mechanism of enhancing the interaction of optical radiation with a superconducting niobium nitride film on the surface of optical waveguides on a lithium niobate substrate using an additional cover layer with a high refractive index has been studied. It has been shown that adiabatic deformation of waveguide modes allows increasing the absorption of light in a superconducting film to the level of ∼1 dB/μm, which makes it possible to manufacture a single photon detector with a quantum efficiency of about 70% on lithium niobate.

Currently, 3D scanning technology is used for high-precision measurements and fixing the geometric shape of various objects. However, when creating a computer 3D-model as a result of processing the array of data obtained from the scanning process, may contain errors. Errors may related to the features of the studied object (material, weight, size, location), functional properties of the software used or they may be the low qualification of the software engineer involved in processing 3D scan data. The task of this work was a finding the technical solutions, which allows one to reconstruct the objects surface, recorded using 3D scanning in the process of creating their computer 3D models. We proposed to use the inverse distance method, which is used in biometry to improve the quality of reconstruction of the 3D surface of a human face. Experiments have shown that the result of the reconstruction makes it possible to increase the accuracy of creating 3D models by recovering gaps in the surface of an object that were made during the 3D scanning process. The proposed approach allows one to construct a 3D surface without solving the triangulation problem, which leads to a reduction in computational costs.

The optical tuning of the power splitting ratio in an integrated optical Y-splitter fabricated on the substrate of a photorefractive lithium niobate crystal (LiNbO3) has been studied. The areas of the Y-splitter that are most sensitive to local external illumination are determined. Tuning of the splitting ratio by 2% was experimentally demonstrated, which can be effectively used to increase the extinction ratio in Mach–Zehnder modulators.

The article describes modern solutions used to create vision systems for autonomous robotic complexes, a device for controlling video sensors, methods for obtaining stereo images, processing and further using them in the navigation system. A functional diagram of the organization of the robotic vision system, which is part of the NIIVK M. A. Kartsev Computing System Research and Development Institute, platform, a brief description of its functions and principles of action. The proposed solution involves placing a pair of optical sensors in the head of the robot, simulating the binocular stereoscopic vision inherent in higher animals. A feature of the development is the rejection of the use of laser, infrared, radio frequency, ultrasound and other active emitters, which reduces energy costs and the cost of products without reducing their reliability.

Modern radio electronic equipment (REE) in various areas of economic activity performs increasingly complex tasks at sites with increased levels of responsibility. This circumstance increases the dependence of the operation of the REE on the uninterrupted power supply and its quality level, as well as on the level of fault tolerance of an important auxiliary part of the REE - power supply system (PSS), which significantly affects the ability of the REE to perform its tasks. The results of the analysis of existing and search for promising ways to ensure a given level of reliability of REE associated with its power supply problems show the need for an integrated approach to choosing the most effective option. It consists in the cumulative implementation of the process indicated by the newly introduced term «reliability of the power supply chain (PSC) of the REE», combining the continuity of supplying REE with electricity of the established level of quality and trouble-free operation of the PSS performing the conversion of the initial electricity to the form and the values of its parameters acceptable for the power supply of the functional units REE. Ways to improve the reliability of the PSC of the REE of ground stationary objects are considered for two of its characteristic types - a computer system (CS) and a telecommunication system (TS) with a single-phase voltage of 220V; 50Hz and the value of power consumption to 3-5kW. In terms of increasing the continuity of electricity supply, the feature of the proposed solutions is the achievement of the set goal by additional use of existing resources of the facilities of the REE installation. In some cases, their limited increase is also envisaged. In order to increase the fault tolerance, the PSS REA suggests: in the centralized part of the PSS - the application of the trunk-modular architecture, the choice of the effective structure, and also the adaptive methods and algorithms for management and redundancy, in the distributed part of the PSS - optimization of the structure and minimization of the number of constituent parts.

The possibility of correcting the power coupling ratio of an integrated optical directional X-coupler upon excitation of a local photorefractive response in the substrate material (LiNbO3) has been analyzed. The X-coupler operation has been numerically simulated, and the regions of its maximum sensitivity to photorefraction have been determined. The correspondence between the calculated and experimental data has been obtained. The maximum correction value of the coupling ratio is 1–2%. The photorefractive correction of the coupling ratio has been used to increase the extinction ratio of a Mach–Zehnder modulator to 47 dB.

The principle of operation of the wideband tunable delay line for microwave signals is presented. Delay is performed after the transfer of the microwave signal to the optical frequency domain. The configuration of the delay line model is described. Bandwidth, losses, and distortion characteristics of the delay line model are experimentally determined.

The paper presents a comparative analysis of the results of clinical laboratory trials carried out on the basis of 10 different medical and preventive treatment facilities drawing on the principles and methodology of evidence-based medicine, which confirmed the certainty of clinical effectiveness of Viferon® medications in the treatment of acute respiratory viral infections (ARVI) and influenza in adults. The algorithm included an assessment of antiviral, immunomodulatory, anti-inflammatory, anti-oxidant actions of the medication under the conditions of concurrent, unmasked, randomized, placebo-controlled, clinical immunological studies and a retrospective analysis in keeping with the “Guidelines for Good Clinical Practice”. Thereby, it was shown that the use of Viferon® medications (suppositories, gel) in the treatment of adults with influenza and ARVI, whether with viral or viral-bacterial etiology, contributes to a statistically significant reduction in duration of principal clinical symptoms and the disease as a whole, as well as a decrease of immune and interferon system imbalance and a faster elimination of viral antigens. On the basis of the proven antiviral therapeutic effectiveness and immunomodulatory action, safety and high tolerability, easy-to-administer form in the outpatient settings, Viferon® has been recommended as a disease-modifying agent in the treatment of influenza and ARVI in adults.

An analysis of the undesirable consequences of using unipolar waveforms of UWB electric field pulses for the assessment of the immunity of electronic devices is presented.

The results of a calculation and experimental research of the influence of nonuniformity of the submerged perforated sheet on steam demand leveling on the evaporation surface are published in the current article. A short description of the PGV test facility and a measuring system whose test section is a transverse “cut” of an actual PGV-1000 steam generator with the internals is presented. The methods of experimental starts are explained and instrumentations are described. A uniformly perforated sheet with the flow section of 5.7% and a nonuniformly perforated sheet with the flow section of 4.3% on the cold half and 8.1% on the hot half were used in the experiments. The system pressure was approximately 7 MPa, the inlet steam flow rate was varied between 4.23 and 7.94 t/h, i.e., the steam velocity on the evaporation surface was 0.15–0.29 m/s. The experimental results were analyzed with (1) the engineering method based on estimating the flow rates of steam on hot and cold half by the experimental values of the pressure drop on submerged list and (2) the STEG code, which was developed for three-dimensional mathematical modeling of the two-phase thermohydraulics in the heat exchanger volume and upgraded. It was established that changing the perforation from a uniform to a nonuniform one increases the residual nonuniformity coefficient, which characterizes the flow of steam from the hot side to the cold side under the sheet. However, the steam separation becomes worse because of a high local residual nonuniformity coefficients near the border of two plates with different perforation levels.

The article evaluates the effectiveness of an artificial neural network use for mathematical processing of the machine tool experimental thermal characteristics. To improve the quality of approximation and the accuracy of forecasting, two types of neural networks were used, namely a network of radially basis functions and a generalized regression neural network. The results of a full-scale thermal experiment of the idling 400V machine tool are presented. Computational experiments of the thermal testing results of a metal cutting machine were carried out to build and test the models under study. The results showed that neural networks perform better than the classical power polynomial model in terms of accuracy and approximation quality. Thus, neural networks can be used to approximate the experimental thermal characteristics of the machine tool in real time.

The required machining accuracy can be realized by compensating the thermal error of the machine tool. The paper presents a method of constructing a system of compensation for the thermal error of the machine tool. The method is based on the part measurement system installed on the machine. A review of studies in the field of precision machining was conducted. The review showed that the methods of correction of machining errors caused by dynamic and static factors using OMM-technology (On Machine Measurement) is presented in the literature. At the same time, the methods of compensation of the thermal error of machine tool built on the use of OMM-technology are poorly represented. Therefore, the practical implementation of control algorithms of the working bodies of the machine allowing one to compensate for its thermal error using OMM-technology is in demand. The methodology contains seven main stages, methodologically covering four areas of research. In addition to the experimental, mathematical and measurement areas of research, they also distinguish the area of software development (preparation of NC programs for CNC machines). It is proved that the presented methodology allows one to develop own automated system of compensation of a thermal error for any machine tool. It is shown that the most important directions of the framework for the improvement of the effectiveness of such system are to ensure the completeness of the experimental base and the accuracy of the adjustment of the thermal error compensation algorithms of the machine tool.

This paper includes the results of an investigation of high-voltage pulse effects on insulators of a 10-kV power line. Experiments have been performed by means of equipment that simulates the simultaneous effect of a pulse disturbance and a power line operating voltage. Critical levels of insulator flashover have been determined. These levels are dependent on the pulse disturbance duration, and a number of other effects. The electric characteristics of insulators degrade when high-voltage pulses are injected on an insulator with power ON. As a result, some insulators have been destroyed. The possible reason of destruction is the presence of latent defects.

Shortcomings of the standard ways for tests of electronic devices for immunity to ultrashort electromagnetic pulses (US EMPs) are considered. The method of a choice of simulators being based on use of key parameters of the pulse electric disturbances induced in critical circuits of equipment is offered. This method allows choosing the simulator or some simulators providing the most severe conditions of tests.

Diarrhea is a symptom of many diseases; its pathogenesis is associated with four main mechanisms: water and electrolyte secretion into the intestinal lumen, osmolarity of the chyme, exudation, and impaired intestinal motility. The clinical manifestations, diagnosis, and therapy of bowel diseases are discussed in terms of the pathogenesis of diarrhea.Диарея является симптомом многих заболеваний, ее патогенез связан с четырьмя основными механизмами: секрецией воды и электролитов в просвет кишки, осмолярностью химуса, экссудацией и нарушением моторики кишечника. Обсуждаются особенности клинических проявлений, диагностики и терапии заболеваний кишечника с учетом патогенеза диареи.

The results of work carried out by the SC77C subcommittee of the International Electrotechnical Commission to produce a system of standards on the protection of the civil infrastructure from high-power electromagnetic influences are analyzed. The main approaches to the development of foreign and Russian standards are compared.

An optical detector and an electronic system have been developed for studying the shape of Cherenkov light pulses from extensive air showers in the TUNKA experiment. Results of measurements on the described experimental setup are presented.

We have considered some shortcomings of the standard way of the assessment of electronic device immunity to high power EMPs. And we offer a way, which is based on the use of key parameters of pulse electric disturbances induced in circuits of equipment. This way allows assessing the dependence of results of testing electronic devices from the degree of conformity of EMPs in test volumes of simulators to typical EMPs, but also from degree of conformity of EMPs formed by simulators to real EMPs.

Spatial distribution of Cerenkov radiation of extensive air shower particles with energies 1013–1016 eV is simulated by the CORSIKA code for conditions and configuration of the Tunka-25 facility. Based on the calculated results, sets of approximating functions are constructed for different primary particles and zenith angles. A comparison of the calculated spatial distribution functions of Cerenkov light with the functions measured on the Tunka-25 facility demonstrates the feasibility of identification of the particle initiating the shower and determination of its energy in the vicinity of the bend point of the cosmic ray spectrum.

The cation distributions in the B-site of the orthoferrites SmFe xMn1−xO3 (x = 0.7, 0.8, 0.9) were studied by 57 Fe Mspectroscopy at room temperature. The spectra showed several nonequivalent sites of the iron ions. Five sextets were used in the fitting of the experimentally observed spectra and each one corresponds to different number of the Fe ions in the next nearest neighboring. A nonrandom cation distribution model in such compounds was proposed to interpret the multi-sextets spectra. According to the electric properties measurements, it was noted that the conductivity increases two times with increasing the Mn content but the activation energy decreases from 0.34 eV down to 0.22 eV. The sample with x = 0.7 is an electron semiconductor while the other samples display hole conduction. The magnetoresistance MR of the studied samples value is of 10% and has a negative sign at room temperature while a positive sign is obtained with temperature raising. © 2004 Elsevier B.V. All rights reserved.

The results of the computational-and-experimental investigation into the two-stage ejector for the emergency cooling system of the core of the water-moderated water-cooled power reactor. The results of experimental investigations performed for the ejector model at the JSC “EREC” and the result of calculations performed using the REMIX CFD code are presented.

While most of the emphasis has been focused on the radiated threat represented by intentional electromagnetic interference, it is clear that the threat from conducted disturbances should not be neglected. Conducted threats include those that are produced by the cable coupling of radiated fields and from the direct injection of conducted disturbances into the wiring of a building. It is well known that in the majority of cases, cables provide the most efficient means of transporting potentially damaging energy into equipment. The first part of this paper describes how electrical disturbances can impact electronic equipment inside a building through the power and earthing circuits. Measured data are summarized to illustrate how electrical signals propagate through the power and earthing circuits from the outside to the inside and what levels of signals create problems with electronic equipment. With this understanding of the impact of transient waveforms on electronic equipment and how these disturbances can propagate throughout a building, calculations are then used to evaluate different types of conducted threats to buildings.

The purpose of this work was to make a computational analysis using the VAPEX thermohydraulic code, developed at the Experimental Scientific-Research Center at the All-Russia Scientific-Research Institute of Nuclear Power Plants, of the L-33 experiment performed on the FARO setup to study the interaction of core melt with water. The calculation of the stage of mixing of the melt stream with water and subsequent cooling satisfactorily predicted experimental parameters such as the temperature of the water and gas in the vessel. The calculation of the formation and propagation of the thermodetonation wave agrees well with the experimental data. Analysis of the experiment showed that the VAPEX code can predict adequately the most important characteristics of melt–coolant interaction during a serious accident at a nuclear power plant in accordance with the out-of-vessel scenario of the development of the accident.

Nonlinear spatial filtering is realized due to the electro-optical effect in spatial light modulators (SLMs). Optical methods with nonlinear filtering are suggested for various optical applications such as optical inspection of photolithography masks, wavefront sensor, etc. A fast optical response of the SLM allows optical inspection with a video (or faster) rate. The optical system proposed is tolerant to the vibrations and temperature variations because of the dynamic properties of the SLM.

We propose a new type of spatial light modulator using nonlinear organic polymer film as a phase modulation element. Using polymer poly-Disperse Red-19 Toluendiiso-cyanate, a more than 150:1 contrast ratio has been realized for electrical addressing in transverse geometry.

The method of calculating the parameters of voltages induced in the aerial of passive high frequency RFID transponder under the influence of pulsed magnetic field is being introduced. In terms of criterion parameters characterizing transponder immunity to pulsed disturbances amplitude of voltage pulse on its input element and Joule integral, equal to energy releasing in this element in case of its disruption, accurate within the multiplier, which is equal to resistance of disrupted element, are taken. The criteria of transponder malfunction are estimated.

The method for evaluating the immunity of digital devices to the influence of repetitive short electromagnetic pulses is proposed. This method makes it possible to choose the optimal characteristics of radiated pulses, and to predict the results of the influence of pulses with arbitrary parameters, etc.

We demonstrate a novel hybrid solar photovoltaic electrical and thermal energy cogeneration system with high efficiency, at potentially reduced overall weight and size compared with current solar energy systems. The new system is based on highly efficient photovoltaic solar cells and tubular water thermal receivers, incorporating holographic spectral beam light guide concentrators resulting in a more cost-effective solution. Details of fabrication and preliminary experimental testing results are presented.

We demonstrate a new material composed of isotropic liquid crystal (ILC) blended with semiconductor nanoparticles, which could result in a novel high-speed, multiple-notch broadband passive optical switch to selectively discriminate bands of electromagnetic radiation in intelligence, surveillance, or reconnaissance systems. The new material has been demonstrated high nonlinear 3 rd order optical Kerr coefficients (lig ht-induced refractive index change, n 2 ) exceeding 100 times of classic nonlinear material CS 2 with n 2 = 1.2E-11 esu. Details of fabrication and experimental results are presented. Keywords: Optical switching, Liquid Crystals (LC), Nanosemicond uctor, Infrared, Visible, Electromagnetic spectrum, Multiple notch, Nonlinear Kerr effect. 1. INTRODUCTION Most current optical switch (OS) architectures [1,2] that have been extensively studied and developed for optical fiber communications, signal processing, imaging, and sensing, are based on microelectromechanical systems (MEMS)

We demonstrate a novel spectral imaging device based on an imaging Fourier transform spectrometer (FTS) with phase delays electro-optically controlled by fast tuning liquid crystal (LC) elements. The electro-optic (EO) tunable multispectral/hyperspectral imaging give the spectral imager significant advantages, including reduction in size and mass for simultaneous 2D spectral imaging, with a high spatial and spectral resolution. The technology is made very attractive for its potential military, medical and remote sensing applications where hyperspectral imaging plays a significant role in detection.

A new design of nuclear power plant (NPP) with pressurized water reactor “NPP-2006” was developed in Russia. It represents the evolutionary development of the designs of NPPs with VVER-1000 reactors. Horizontal steam generator PGV-1000 MKP with in-line arrangement of the tube bundles will be used in “NPP-2006”. PGV test facility was constructed at the Electrogorsk Research and Engineering Center on NPP Safety (EREC) to investigate the process of the steam separation in steam generator. The description of the PGV test facility and tests, which will be carried out at the facility in 2009, are presented in this paper. The experimental results will be used for verification of the 3D thermal-hydraulic code STEG, which is developed in EREC. STEG pretest calculation results are presented in the paper.Copyright © 2009 by ASME

An efficient method for suppressing the competition between counterpropagating waves and stabilizing the beats was developed for a rotating solid-state ring laser with a homogeneously broadened gain profile of the active medium. Use was made of self-pumping waves created under the conditions of steady-state mode locking using a diffraction acoustooptic feedback loop. Experimental and theoretical investigations were made of the influence of such self-pumping waves, of the laser parameters, and of the nonreciprocal acoustooptic effects on the amplitude-frequency characteristics of a YAG:Nd3+ ring laser. Considerable distortions of the frequency characteristics of this laser observed under transient mode locking conditions were due to the appearance of frequency modulation of ultrashort pulses. Weakening of the coupling between the counterpropagating waves, optimization of the parameters of the acoustooptic feedback loop, and detuning of the modulation frequency from the intermode value established a stable beat regime characterized by slight distortions of the frequency characteristics even near the interval of locking of the counterpropagating wave frequencies.

Image intensifier tubes, as part of night vision devices, have been the primary devices for the detection and amplification of near infrared light for night vision operations. In this paper, we demonstrate a novel all-optical night vision amplifier device with a potential to replace the image intensifier tube in night vision goggles. This image amplifier is based on a novel structure of semiconductor and spectrally tunable liquid crystal (LC) materials within a thin cell. The LC reacts to near-infrared (NIR) radiation but is unaffected by visible light, allowing see-through capability including visible-wavelength cockpit light. The technology is made very attractive by its high sensitivity, spatial resolution, and contrast without expensive, bulky, and heavy optics or high-voltage components.

A calculation model to estimate data channel degradation due to the influence of periodically repeating voltage pulses is presented in this paper. These periodically repeating voltages can be caused by accidental or intentional disturbances that are either injected onto a communications line or coupled to the line by a radiated field. Comparative analysis of the influence of different pulse disturbances of equal average power is performed. The developed calculation model is justified by means of experiments.

A new method for creating self-pumping waves in a solid-state laser with a YAG:Nd3+ active element was based on the use of an antiresonant acoustooptic diffraction feedback, acting under conditions of mode locking in a laser with a (in an acoustooptic switch) resonator axis self-intersecting at an angle close to twice the Bragg angle. The acoustooptic feedback and self-diffraction, in the active medium, of counterpropagating waves and of self-pumping waves (generated by diffraction of the counterpropagating waves in the acoustooptic switch) ensured an effective stabilization of the mode locking parameters, of the parameters of ultrashort output pulses, and of bidirectional lasing generating counterpropagating waves with different frequencies. In a symmetric ring solid-state laser a double passage of the counterpropagating waves through the switch suppressed completely the nonreciprocal acoustooptic effects resulting from the Bragg diffraction of these waves in a conventional ring laser. An asymmetry of the ring resonator and suppression of the interaction between the counterpropagating and self-pumping waves in the active medium revealed optical bistability of ultrashort pulses, particularly when the difference between the counterpropagating wave frequencies or the power or frequency of an ultrasonic wave in the acoustooptic switch were varied.

New design of nuclear power plant with pressurized water reactor entitled “NPP-2006” is under progress in Russia. It is evolutionary type of design based on existing NPP with VVER-1000 reactors. Intensive thermal-hydraulic experimental activities support design development. They are aimed at increasing of NPP safety and efficiency. Integral test facility PSB-VVER, modeling main components of primary system of VVERs, is the main tool for experimental studies. Volumetric-power scale of the test facility is 1:300, elevations are 1:1. A core model is an assembly of 168 fuel rod imitators. About 20 experiments at the PSB-VVER have been performed to generate experimental data base for validation of best estimate thermal-hydraulic system codes for application to analyses of VVERs transients and accidents. An important direction of PSB-VVER experimental activities is connected with the development and verification of accident management procedures. 15 experiments have been conducted to support development of such procedures. For new plant design (hydroaccummulators, operating under low pressure) is under experimental studies at the PSB-VVER. The experimental program also includes the approach, based on investigations of local thermal-hydraulic parameters in the fuel rod imitators assembly at the large-scale test facility. This approach is supposed to decrease a level of design conservatism and to enhance NPP efficiency.Copyright © 2006 by ASME

An inexpensive, easily integrated, 40 Gbps photoreceiver operating in the communications band would revolutionize the telecommunications industry. While generation of 40 Gbps data is not difficult, its reception and decoding require specific technologies. We present a 40 Gbps photoreceiver that exceeds the capabilities of current devices. This photoreceiver is based on a technology we call "nanodust." This new technology enables nanoscale photodetectors to be embedded in matrices made from a different semiconductor, or directly integrated into a CMOS amplification circuit. Photoreceivers based on quantum dust technology can be designed to operate in any spectral region, including the telecommunications bands near 1.31 and 1.55 micrometers. This technology also lends itself to normal-incidence detection, enabling a large detector size with its associated increase in sensitivity, even at high speeds and reception wavelengths beyond the capability of silicon.

Advances in the development of imaging sensors depend upon (among other things) the testing capabilities of research laboratories. Sensors and sensor suites need to be rigorously tested under laboratory and field conditions before being put to use. Real-time dynamic simulation of real targets is a key component of such testing, as actual full-scale tests with real targets are extremely expensive and time consuming and are not suitable for early stages of development. Dynamic projectors simulate tactical images and scenes. Several technologies exist for projecting IR and visible scenes to simulate tactical battlefield patterns - large format resistor arrays, liquid crystal light valves, Eidophor type projecting systems, and micromirror arrays, for example. These technologies are slow, or are restricted either in the modulator array size or in spectral bandwidth. In addition, many operate only in specific bandwidth regions. Physical Optics Corporation is developing an alternative to current scene projectors. This projector is designed to operate over the visible, near-IR, MWIR, and LWIR spectra simultaneously, from 300 nm to 20 μm. The resolution is 2 megapixels, and the designed frame rate is 120 Hz (40 Hz in color). To ensure high-resolution visible imagery and pixel-to-pixel apparent temperature difference of 100°C, the contrast between adjacent pixels is >100:1 in the visible to near-IR, MWIR, and LWIR. This scene projector is designed to produce a flickerless analog signal, suitable for staring and scanning arrays, and to be capable of operation in a hardware-in-the-loop test system. Tests performed on an initial prototype demonstrated contrast of 250:1 in the visible with non-optimized hardware.

Optical fiber has been used to develop various sensors such as temperature, pressure, magnetic field, stress, moisture, etc. A recent development in optical fiber technology due to fiber communication has drawn lot of interests in developing new optical fiber sensor. It has several advantages over conventional sensors. This paper will describe some of our works on the application of optical fiber sensors for the measurement of strain and moisture.

A polymer film surface modified by laser illumination was used as a command surface for nematic liquid crystal (LC). Azobenzene-containing polyurethanes were taken for the material of the film. A relief grating inscribed by laser illumination onto the surface of these polymers induced a reorientation of the LC director from the initial homeotropic alignment. Possible applications of the described processes include command-surface creation for liquid-crystal displays, reversible and adaptable liquid-crystal structures for laser-beam targeting and aiming, etc.

A new method is proposed for controlling the amplitude-frequency characteristics of a rotating ring solid-state laser with a homogeneously broadened gain profile of the active medium operating under mode-locked conditions. This method involves the use of ultrashort self-pumping pulses generated by a time-dependent diffraction acoustooptic feedback loop and characterized by a Doppler-modulated optical frequency. It was found experimentally that time-dependent self-diffraction of the main and self-pumping ultrashort pulses by interference population-inversion gratings induced in the active medium gives rise to a new nonreciprocal optical effect (self-induced alternating-sign difference between the frequencies of the counterpropagating waves) and stabilizes the beat regime in such a ring laser.

Diffraction modulator exploiting transverse electro-optic effect in ferroelectric liquid crystals is proposed for display applications. Experiments performed with short pitch ferroelectric liquid crystal aligned homeotropically showed that an achromatic contrast ratio better than 100:1 available with oblique readout. The sources of the contrast deterioration and a tolerance of the proposed scheme to them are analyzed. For the selected directions of readout the light output obtains low sensitivity to the polarization of readout light.

The deep underwater Cherenkov neutrino telescope NT-200 is currently under construction at Lake Baikal. The "subdetectors" NT-36 (1993-95) and NT-72 (1995-96) have been operating successfully over 3 years. Various techniques have been developed to search for magnetic monopoles with these arrays. Here we describe a method used to detect superheavy slowly moving (beta = v/c = 0.00001 - 0.001) monopoles catalyzing baryon decay. We present results obtained from the preliminary analysis of the data taken with NT-36 detector in 1993. Furthermore, possibilities to observe faster (beta = 0.2 - 1) monopoles via other effects are discussed.

Organic polymer photoconductors are considered as a perspective materials for optically addressed spatial light modulators. A few type of materials were tested. Approach to the choice of materials is suggested.© (1996) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

A few optical schemes are considered and discussed for display devices, based on liquid crystal image converters. These schemes promise enhancement in light output and diminishing in system sizes in comparison to well-known ones realized yet.