Showing papers in "Optoelectronics, Instrumentation and Data Processing in 2017"
TL;DR: In this paper, a review of studies carried out by the staff of the National Research University of Information Technologies, Mechanics and Optics (ITMO University, Saint-Petersburg) and the Institute of Automation and Electrometry of the Siberian Branch of the Russian Academy of Sciences (IAE SB RAS, Novosibirsk) in the field of development of laser engineering processes for the formation of the structure of diffractive optical elements (DOEs) and photomasks with amplitude binary and grayscale transmission is presented.
Abstract: This paper is a review of studies carried out by the staff of the National Research University of Information Technologies, Mechanics and Optics (ITMO University, Saint-Petersburg) and the Institute of Automation and Electrometry of the Siberian Branch of the Russian Academy of Sciences (IAE SB RAS, Novosibirsk) in the field of development of laser engineering processes for the formation of the structure of diffractive optical elements (DOEs) and photomasks with amplitude binary and grayscale transmission. This paper also describes the results of the study of laser thermochemical technology for fabricating chrome DOEs and technologies for the fabrication of grayscale DOEs and photomasks based on the use of amorphous silicon and LDW glass.
17 citations
TL;DR: The mechanism of charge transport in MIS structures on the basis of thin hafnium and zirconium oxide films is studied in this article, where it is shown that transport in the studied materials is limited by phonon assisted tunneling between traps.
Abstract: The mechanism of charge transport in MIS structures on the basis of thin hafnium and zirconium oxide films is studied. It is shown that transport in the studied materials is limited by phonon assisted tunneling between traps. From the comparison of experimental current-voltage characteristics of MIS structures n-Si/HfO2/Ni and n-Si/ZrO2/Ni, the estimated, thermal, and optical energies of traps are determined. It is shown that oxygen vacancies are localization centers (traps) of charge carriers in HfO2 and ZrO2.
17 citations
TL;DR: In this paper, a brief overview of the non-paraxial effects arising from the use of the lensacon proposed by Koronkevich and co-authors in 1993, as well as its analogs in a substantially nonparametric mode is presented.
Abstract: This paper presents a brief overview of papers dealing with the nonparaxial effects arising from the use of the lensacon proposed by Koronkevich and coauthors in 1993, as well as its analogs in a substantially nonparaxial mode. In this case, it is necessary to take into account the vector nature of electromagnetic radiation. This allows detecting new effects, which, in turn, would extend the range of applications of the lensacon.
16 citations
TL;DR: The efficiency of methods of the spectral-spatial classification of similarly looking types of vegetation on the basis of hyperspectral data of remote sensing of the Earth, which take into account local neighborhoods of analyzed image pixels, is experimentally studied.
Abstract: The efficiency of methods of the spectral-spatial classification of similarly looking types of vegetation on the basis of hyperspectral data of remote sensing of the Earth, which take into account local neighborhoods of analyzed image pixels, is experimentally studied. Algorithms that involve spatial pre-processing of the raw data and post-processing of pixel-based spectral classification maps are considered. Results obtained both for a large-size hyperspectral image and for its test fragment with different methods of training set construction are reported. The classification accuracy in all cases is estimated through comparisons of ground-truth data and classification maps formed by using the compared methods. The reasons for the differences in these estimates are discussed.
14 citations
TL;DR: In this article, an automated system of acquisition of raw experimental data and a control system for operation modes of an experimental large-scale separation column are described, and the influence of a new method of irrigation of a structured packing on the separation column efficiency is studied.
Abstract: An automated system of acquisition of raw experimental data and a control system for operation modes of an experimental large-scale separation column are described. The influence of a new method of irrigation of a structured packing on the separation column efficiency is studied. Based on the data obtained by the developed automated system, a 20–30% increase in the efficiency of mixture separation on a structured packing is expected.
12 citations
TL;DR: Analysis of the results of estimating the accuracy of a digital relief model created using the ArcGIS 10 geoinformation system shows that the best results are obtained using spline methods and inverse distance weighting.
Abstract: Interpolation methods for creating digital elevation models using geoinformation system data are considered. For this purpose, the best-known methods are analyzed: inverse distance weighting (IDW), the Krige (or kriging) method, ANUDEM, spline interpolation, the natural neighbor method, and the method based on the construction of a triangular irregular network (TIN) model). The modeling accuracy is estimated for the area located between the Ui, Tara, and Irtysh Rivers in the Omsk region of West Siberia (Russia). Analysis of the results of estimating the accuracy of a digital relief model created using the ArcGIS 10 geoinformation system shows that the best results are obtained using spline methods and inverse distance weighting.
11 citations
TL;DR: In this paper, a method is developed to ensure precise alignment of the origin of a polar coordinate system in which the laser beam position is defined in writing diffractive optical elements with the optical workpiece rotation axis.
Abstract: A method is developed to ensure precise alignment of the origin of a polar coordinate system in which the laser beam position is defined in writing diffractive optical elements with the optical workpiece rotation axis. This method is used to improve the accuracy of a circular laser writing system in writing large-scale diffractive optical elements in a polar coordinate system. Results of studying new algorithms of detection and correction of positioning errors of the circular laser writing system in the course of writing are reported.
10 citations
TL;DR: A simplified method of plane trajectory calculation is proposed for solving the problem of planning a path defined by a sequence of waypoints using clothoids joined by clothoids (Cornu spirals).
Abstract: A simplified method of plane trajectory calculation is proposed for solving the problem of planning a path defined by a sequence of waypoints. The trajectory consists of oriented segments of straight lines joined by clothoids (Cornu spirals). The efficiency of the method is validated by means of numerical simulations in the MATLAB/Simulink environment.
10 citations
TL;DR: A problem of design of a robust controller for an unsteady nonaffine (in terms of the input) a priori uncertain dynamic plant is considered and the quality of the designed control system performance is illustrated through simulations.
Abstract: A problem of design of a robust controller for an unsteady nonaffine (in terms of the input) a priori uncertain dynamic plant is considered. The quality of the designed control system performance is illustrated through simulations.
10 citations
TL;DR: In this article, a monochromator capable of suppressing spurious laser radiation to a level required for low-frequency (<100 cm−1) Raman spectroscopy is proposed, which has a high spectral resolution, contains a small number of optical elements, and can be easily included into the experimental optical scheme.
Abstract: A monochromator capable of suppressing spurious laser radiation to a level required for low-frequency (<100 cm−1) Raman spectroscopy is proposed. It has a high spectral resolution, contains a small number of optical elements, and can be easily included into the experimental optical scheme. The effect of using this monochromator in low-frequency Raman spectroscopy is illustrated by examples with test samples.
10 citations
TL;DR: The approach to solving the problem of recovery of blurred images with a known point scattering function by constructing an inverse filter model by the least squares method with a given weight function is proposed.
Abstract: This paper touches upon the problems of constructing a basis for stochastic functions, which represent samples of random numbers with a given distribution law. The algorithm for constructing an approximation model with the use of this basis is described. The general algorithm for signal recovery using the stochastic basis by the least squares method with a given weight function is given. The approach to solving the problem of recovery of blurred images with a known point scattering function by constructing an inverse filter model is proposed.
TL;DR: In this paper, a high-aspect pseudometallic structures were used to construct a quasioptical high-pass subterahertz filter with a cutoff frequency of 0.275 THz.
Abstract: This paper describes a technological approach to the implementation of quasioptical high-pass subterahertz filters with the use of high-aspect pseudometallic structures. The approach is based on micropatterning a solid polymer layer of polymethylmethacrylate by means of synchrotron X-ray lithography with subsequent metallization of the entire surface of the structure. A fabricated specimen and operational characteristics for the filter with a cutoff frequency of 0.275 THz, which has the thickness of 1 mm and is formed by hexagon-shaped through-holes arranged on a triangular lattice with 70-μm wide crosspieces, are demonstrated.
TL;DR: In this paper, a capacitive accelerometer for measuring high-g accelerations (up to 106 g and higher) was proposed, where insertion of a thin electret film with a high surface potential into the gap between the electrodes ensures significant expansion of the frequency and amplitude ranges of acceleration measurements, whereas the size of the proposed device is smaller than that of available MEMS accelerometers.
Abstract: A possibility of creating a capacitive accelerometer for measuring high-g accelerations (up to 106
g and higher) is discussed. It is demonstrated that insertion of a thin electret film with a high surface potential into the gap between the electrodes ensures significant expansion of the frequency and amplitude ranges of acceleration measurements, whereas the size of the proposed device is smaller than that of available MEMS accelerometers for measuring high-g accelerations. A mathematical model of an electret accelerometer for high-g accelerations is developed, and the main specific features of accelerometer operation are analyzed.
TL;DR: This paper presents a new approach to designing an automated system for monitoring and controlling the process of applying porous insulation material on a conductive cable core, which is based on using structurally and parametrically optimized digital controllers of an arbitrary order instead of calculating typical PID controllers using known methods.
Abstract: This paper presents a new approach to designing an automated system for monitoring and controlling the process of applying porous insulation material on a conductive cable core, which is based on using structurally and parametrically optimized digital controllers of an arbitrary order instead of calculating typical PID controllers using known methods. The digital controller is clocked by signals from the clock length sensor of a measuring wheel, instead of a timer signal, and this provides the robust properties of the system with respect to the changing insulation speed. Digital controller parameters are tuned to provide the operating parameters of the manufactured cable using a simulation model of stochastic extrusion and are minimized by moving a regular simplex in the parameter space of the tuned controller.
TL;DR: In this article, a method for recovering digital holograms obtained at small angles between interfering wave fields is described, and the technique for obtaining data on the phase of the wavefront reflected from the object is under consideration.
Abstract: This paper describes the method for recovering digital holograms obtained at small angles between interfering wave fields. The technique for obtaining data on the phase of the wavefront reflected from the object is under consideration.
TL;DR: In this article, a method of improving the accuracy of a circular laser system in fabrication of large-diameter diffractive optical elements by means of a polar coordinate system and the results of their use is presented.
Abstract: This paper presents a method of improving the accuracy of a circular laser system in fabrication of large-diameter diffractive optical elements by means of a polar coordinate system and the results of their use. An algorithm for correcting positioning errors of a circular laser writing system developed at the Institute of Automation and Electrometry, SB RAS, is proposed and tested. Highprecision synthesized holograms fabricated by this method and the results of using these elements for testing the 6.5 m diameter aspheric mirror of the James Webb space telescope (JWST) are described..
TL;DR: In this paper, the nonradiation (Forster) energy transfer between a dye J-aggregate and closely located nanoparticles possessing the properties of two-level systems is described by deriving the equations that characterize the density matrix dynamics in a twolevel medium and the evolution of exciton pulses in an extended quasione-dimensional dye Jaggregate.
Abstract: This paper describes the nonradiation (Forster) energy transfer between a dye J-aggregate and closely located nanoparticles possessing the properties of two-level systems. Nanoparticles can be quantum dots (QDs) or a spherical symmetric package of atoms. The dynamics of the process is described by deriving the equations that characterize the density matrix dynamics in a two-level medium and the evolution of exciton pulses in an extended quasi-one-dimensional dye J-aggregate. It is shown that effective controlled resonant transfer of the energy stored in QDs is implemented in the system and manifested in the amplification of the exciton pulses. In turn, there is a possibility of the reverse process of exciton energy transfer in partial inversion of two-level transitions of QDs. The results of this paper are confirmed by the experimental data from the literature.
TL;DR: Generalized static mathematical models for two double-axis accelerometers as part of the inclination parameter converter are obtained, which ensure accurate determination of the spatial orientation angles of an object: zenith and sighting (apsidal) angles.
Abstract: Various aspects of mathematical modeling of the inclination parameter converter based on two double-axis accelerometers in a single integrated design are considered. Possible variants of design patterns of such a converter are presented. Additional turns of the accelerometer sensors mounted in the converter body are considered. Generalized static mathematical models for two double-axis accelerometers as part of the inclination parameter converter are obtained, which ensure accurate determination of the spatial orientation angles of an object: zenith and sighting (apsidal) angles.
TL;DR: In this article, a two-component fluxgate magnetic gradiometer with coaxial fluxgates is presented, and the locations of the gradiometers are modeled as functions of the magnitude and direction of the geomagnetic field strength vector.
Abstract: Issues of designing fluxgate magnetic gradiometers are considered. The areas of application of fluxgate magnetic gradiometers are determined. The structure and layout of a two-component fluxgate magnetic gradiometer are presented. It is assumed that the fluxgates are strictly coaxial in the gradiometer body. Elements of the classical approach to the mathematical modeling of the spatial arrangement of solids are considered. The bases of the gradiometer body and their transformations during spatial displacement of the gradiometer are given. The problems of mathematical modeling of gradiometers are formulated, basic mathematical models of a two-component fluxgate gradiometer are developed, and the mathematical models are analyzed. A computer experiment was performed. Difference signals from the gradiometer fluxgates for the vertical and horizontal position of the gradiometer body are shown graphically as functions of the magnitude and direction of the geomagnetic field strength vector.
TL;DR: In this article, the spectral properties of stratified structures consisting of two volume holographic reflection gratings separated by an optically uniform layer were investigated. But the results showed that the nonuniformity of the internal structure of the holographic gratings due to the imperfection of the recording medium substantially distorts the spectral characteristics of the studied structures in comparison with their simple theoretical models.
Abstract: This paper presents the results of experimental studies of the spectral properties of stratified structures consisting of two volume holographic reflection gratings separated by an optically uniform layer. When such structures are illuminated by polychromatic light, the interference of the waves generated by these gratings leads to the formation of a set of narrow spectral passbands. The period of arrangement of the passbands is determined by the optical thickness of the intermediate layer, and their envelope coincides with the spectral selectivity contour of one grating. The existence of this type of spectra with local passbands spaced 2–8 A apart (in different experiments) was confirmed experimentally. A high-resolution Ramanor U1000 spectrometer and an optical Fabry–Perot interferometer were used. It is found that the nonuniformity of the internal structure of the holographic gratings due to the imperfection of the recording medium substantially distorts the spectral characteristics of the studied structures in comparison with their simple theoretical models: the spectrum is asymmetric and the transmission of the local bands is significantly lower than the estimated value. Similarity between the experimental data and simulation results was achieved by selecting the parameters of said nonuniformity.
TL;DR: In this article, a review of advanced equipment for automated interference measurements developed at the All-Russian Research Institute for Optical and Physical Measurements is given, including three types of interference microscopes based on the Linnik, Twyman-Green, and Fizeau interferometers with the use of the phase stepping method.
Abstract: A review of advanced equipment for automated interference measurements developed at the All-Russian Research Institute for Optical and Physical Measurements is given. Three types of interference microscopes based on the Linnik, Twyman–Green, and Fizeau interferometers with the use of the phase stepping method are presented.
TL;DR: In this article, shape features of the surface structures of multifocal intraocular lenses (IOLs) are considered, which, unlike bifocal IOLs, generate additional foci or extend the depth of focus.
Abstract: This paper considers shape features of the surface structures of multifocal intraocular lenses (IOLs), which, unlike bifocal IOLs, generate additional foci or extends the depth of focus, which not only corrects near and far vision but also provides good vision at intermediate distances. Expansion of the field of clear vision is achieved due to the effects of diffraction, interference, and refraction (change in the radius of curvature of the lens surface). The optical characteristics of the most famous multifocal IOLs (trifocal and quadrafocal lenses and lenses with extended focal area) are given.
TL;DR: An adaptive control algorithm structure is proposed which limits the amplitude of high-frequency oscillations in the control system with a change in the direction of motion of the rod of the hydraulic cylinders and provides the desired accuracy and quality of transients at all stages of structural loading history.
Abstract: The problem of control system design for a strength testbed of aircraft structures is considered. A method for calculating the parameters of a proportional-integral controller (control algorithm) using the time-scale separation method for the testbed taking into account the dead time effect in the control loop is presented. An adaptive control algorithm structure is proposed which limits the amplitude of high-frequency oscillations in the control system with a change in the direction of motion of the rod of the hydraulic cylinders and provides the desired accuracy and quality of transients at all stages of structural loading history. The results of tests of the developed control system with the adaptive control algorithm on an experimental strength testbed for aircraft structures are given.
TL;DR: In this article, computer simulation was performed for the measurement process of the parameters of MIOL-Akkord bifocal diffractive-refractive lenses in which the central area of the diffractive element is reduced and spherical aberrations of the eye are compensated.
Abstract: Computer simulation was performed for the measurement process of the parameters of MIOL-Akkord bifocal diffractive-refractive lenses in which the central area of the diffractive element is reduced and spherical aberrations of the eye are compensated. The spatial-energy characteristics of an ideal diffractive lens are preliminarily calculated using existing formulas. The simulation of the process of controlling the intraocular lens parameters has shown that the intensity distribution along the optical axis does not characterize the diffraction efficiency, which is the total (integrated) intensity in the beam cross section at the focus. It has been found that due to the mutual influence of diffraction orders, it is difficult to measure the absolute diffraction efficiency and it is better to evaluate only the relative efficiency.
TL;DR: In this paper, the problems and prospects of using diffractive elements with a sawtooth relief-phase microstructure in imaging optical systems are analyzed, focusing on minimizing the adverse side effect of diffraction orders on the quality of the image formed by an optical system with a diffractive element due to the changeover from single-layer microstructures to structures containing several layers and reliefs.
Abstract: The problems and prospects of using diffractive elements with a sawtooth relief-phase microstructure in imaging optical systems are analyzed. Particular attention is paid to minimizing the adverse side effect of diffraction orders on the quality of the image formed by an optical system with a diffractive element due to the change-over from single-layer microstructures to structures containing several layers and reliefs. Requirements are formulated for the design parameters of the microstructure and operating conditions of diffractive elements in optical systems that ensure no visible halo caused by adverse diffraction orders. It is shown by a number of examples that the use of a diffractive element in a plastic-lens imaging optical system corrects chromatic aberrations and provides high resolution in the generated image.
TL;DR: The design can be used to match the potentials of two parallel-connected power sources for the fundamental harmonic at the moments of switching the stator windings of an induction AC motor from a converter to a centralized power- supply system and back.
Abstract: This paper presents the results of designing a joint phase-locked loop for adjusting the phase shifts (speed) and Euclidean norm of three-phase voltages of an inverter to the same grid parameters. The design can be used, in particular, to match the potentials of two parallel-connected power sources for the fundamental harmonic at the moments of switching the stator windings of an induction AC motor from a converter to a centralized power-supply system and back. Technical implementation of the developed synchronization algorithm will significantly reduce the inductance of the current-balancing reactor and exclude emergency operation modes in the electric motor power circuit.
TL;DR: It is shown that the computational procedures for processing seismic signals are quite simple and can therefore be used in real-time systems with modest requirements for computational resources.
Abstract: A method for classifying moving objects having a seismic effect on the ground surface is proposed which is based on statistical analysis of the envelopes of received signals. The values of the components of the amplitude spectrum of the envelopes obtained applying Hilbert and Fourier transforms are used as classification criteria. Examples illustrating the statistical properties of spectra and the operation of the seismic classifier are given for an ensemble of objects of four classes (person, group of people, large animal, vehicle). It is shown that the computational procedures for processing seismic signals are quite simple and can therefore be used in real-time systems with modest requirements for computational resources.
TL;DR: An eddy current testing method based on the use of an exciting signal of special shape that makes it possible to calculate the measuring sensor parameters at different frequencies and to construct an experimental hodograph of the sensor–test object system is proposed.
Abstract: An eddy current testing method based on the use of an exciting signal of special shape is proposed. Subsequent digital processing of the detected output signal makes it possible to calculate the measuring sensor parameters at different frequencies and to construct an experimental hodograph of the sensor–test object system. Experiments performed for materials with different physical and geometrical characteristics of constructing hodographs have shown that the proposed method provides a reliable separation of the main factors affecting the results of multi-frequency eddy current measurement. The results can be used in automated systems for inspection and non-destructive testing of materials and products.
TL;DR: A method is proposed, which allows control actions for the follower robot to be formed only on the basis of information about the follower motion parameters and the relative positions of the leader and follower.
Abstract: A problem of control of quadrotors in a leader–follower formation is considered. A method is proposed, which allows control actions for the follower robot to be formed only on the basis of information about the follower motion parameters and the relative positions of the leader and follower.
TL;DR: In this paper, a diffraction corrector and imitator for the interferometric control of the surface shape of the 6m main mirror of the Russian Academy of Sciences was described.
Abstract: This paper describes the development and manufacture of diffraction corrector and imitator for the interferometric control of the surface shape of the 6-m main mirror of the Big Azimuthal Telescope of the Russian Academy of Sciences. The effect of errors in manufacture and adjustment on the quality of the measurement wavefront is studied. The corrector is controlled with the use of an off-axis diffraction imitator operating in a reflection mode. The measured error is smaller than 0.0138λ (RMS).