Computer Optics

871-875

Authors: A.G. Nalimov

We show that a 70-nm dielectric nanoparticle placed on the optical axis near the surface (at a distance less than 100 nm) of a high-NA gradient microlens made of silicon, which is illuminated by a laser beam of 1.55 μm wavelength, is attracted to the lens surface with a piconewton force. The profile of the lens refractive index is described by a hyperbolic secant function. If a cut-out is made in the lens output surface, then the nanoparticle will be pulled into this cut-out, producing a kind of 'optical magnet'. If a reverse energy flow is to be generated on the optical axis near the output surface of such a gradient lens, this will lead to an absorbing dielectric nanoparticle being pulled toward the surface with a greater force than a similar non-absorbing particle. In the absence of a reverse flow, both absorbing and non-absorbing particles will be attracted to the surface with an equal force. The electromagnetic fields involved are calculated using a finite difference time domain (FDTD) method and the acting forces are calculated using a Maxwell stress tensor.

883-892

Authors: E.V. Byzov, L.L. Doskolovich, S.V. Kravchenko, N.L. Kazanskiy

A new source-target mapping for the design of refractive optical elements generating prescribed 2D intensity distributions is proposed. The calculation of the optical element is reduced to the solution of ordinary explicit differential equations. The simulation results presented demonstrate high performance of the proposed method. While generating uniform rectangular intensity distributions with angular dimensions varying from 80°×1° to 40°×20°, the normalized root-mean-square deviations between the generated and required distributions do not exceed 15 %.

901-908

Authors: V.V. Kotlyar, A.A. Kovalev, E.S. Kozlova, A.P. Porfirev

We investigate a multispiral phase plate (MSPP) with multiple centers of phase singularity arbitrarily located in the MSPP plane. Equations to describe the topological charge of an optical vortex in the initial plane immediately behind the MSPP and orbital angular momentum (OAM) normalized relative to the beam power are derived. The topological charge in the initial plane is found as a sum of the topological charges of all singularities if their centers are located inside a finite-radius circular aperture. If the phase singularity centers are partially located on the boundary of a circular diaphragm limiting the MSPP, the total topological charge is found as the sum of all singularities divided by 2. Total OAM that the vortex carries depends on the location of the singularity centers: the farther from the center of the plate the singularity center is located, the smaller is its contribution to the OAM. If all singularity centers are located on the boundary of the diaphragm limiting MSPP, then the OAM of the vortex beam equals zero, although in this case the topological charge of the beam is nonzero.

917-922

Authors: V.S. Soloviev, S.P. Timoshenkov, A.S. Timoshenkov, A.I. Vinogradov, N.M. Kondratiev, N.A. Raschepkina

The numerical simulation and selection of optimal parameters of the diffraction grating for a newly developed technology for the manufacture of plane waveguide systems are performed. In contrast to the use of ready-made silicon wafers on an insulator, the new technology has been developed for the manufacture of a fully autonomous radiation input system, a coupling element and the waveguide itself. A general description of the technology of the ‘radiation input – propagation – radiation output’ system is given. Concrete fabrication parameters of the lattice height, the substrate and coating layers are found. The coupling efficiency of radiation input into the waveguide is found to be 30%.

931-936

Authors: G.I. Greisukh, I.A. Levin, S.V. Kazin

For medium- and long-wavelength dual-band infrared refractive and refractive-diffractive thermal imaging zoom lenses of simple design, we show that it is possible to maintain superb and practically unchanged optical characteristics across the temperature range from –40 to +40°C in the entire range of focal length variation. Athermalization for any focal length is achieved by moving one double-lens component or a single lens along the optical axis of the lens. Considering that these optical components are not involved in the zooming process, it becomes possible to both compensate for thermal defocusing and focus the lens on the object of interest using the same focusing mechanism, while maintaining the size and tightness of the optical system.

944-950

Authors: S.P. Ye, C.X. Chen, A. Nedzved, J. Jiang

The buildings are very complex for detection on SAR images, where the basic features of those are shadows. There are many different representations for SAR shadow. As result it is no possible to use convolutional neural network for building detection directly. In this article we give property analysis of SAR shadows of different type buildings. After that, each region (ROI) prepared for training of building detection is corrected with its own SAR shadow properties. Reconstructions of ROI will be put in a modified YOLO network for building detection with better quality result.

959-967

Authors: E.E. Berlovskaya, O.P. Cherkasova, I.A. Ozheredov, T.V. Adamovich, E.S. Isaychev, S.A. Isaychev, A.M. Makurenkov, A.N. Varaksin, S.B. Gatilov, N.I. Kurenkov, A.M. Chernorizov, A.P. Shkurinov

We propose a new approach to non-contact recording of respiratory function based on the analysis of a sequence of Infrared-terahertz images of the human face, allowing the processes that occur during breathing to be visualized. To obtain quantitative estimates of the respiratory function, two methods are proposed. The first one utilizes a probe which implements the function of spatial differentiation and provides high sensitivity, but requires an increased accuracy of positioning the probe at the nasal opening and scaling in accordance with the camera angle. The other one is a histogram method for obtaining quantitative estimates of the external respiratory function, which is scale invariant and does not require precise positioning, but has a lower sensitivity compared to the first one. The methods proposed have made it possible to remotely evaluate the respiratory rate, which correlates well with the data obtained by a contact method of respiratory function registration.

978-984

Authors: A.L. Timofeev, A.Kh. Sultanov

The article considers a method of error-correcting coding based on the holographic representation of a digital signal. The message encoding process is a mathematical simulation of a hologram created in virtual space by a wave from an input signal source. The code word is a hologram of a point, it is also a one-dimensional zone ruler that carries information about the input data block in the form of an n-bit code of the coordinate of the center of the Fresnel zones. It is shown that the holographic representation of the signal has significantly greater noise immunity and allows you to restore the original digital combination when most of the code message is lost and when the encoded signal is distorted by noise several times higher than the signal level. To assess the noise immunity, the reliability of information transmission over the channel with additive white Gaussian noise is compared using the Reed-Solomon code, the Reed-Muller code, the majority code, and the holographic code. The comparative efficiency of codes in the presence of packet errors caused by the effect of fading due to multipath propagation in radio channels is considered. It is shown that holographic coding provides the correction of packet errors regardless of the length of the packet and its location in the codeword. The holographic code is of interest for transmitting information over channels with a low signal-to-noise ratio (space communications and optical communication systems using free space as a transmission channel, terrestrial, including mobile radio communications), as well as for storing information in systems exposed to ionizing radiation.

990-994

Authors: W.Z. Yi

The planning of rural land space utilization is a very important problem. In this paper, the objective function of rural land use planning was analyzed firstly, and then the improved particle swarm optimization (IPSO) algorithm was obtained by improving the inertia weight for solution. The results showed that the land space use in the study area was more reasonable after the planning based on the IPSO algorithm, the forest land and construction land increased, the area of grassland, cultivated land and water area reduced appropriately, the aggregation degree of all types of land improved, and the space distribution was more planned, which was more conducive to production activities. The analysis results verify the effectiveness of the IPSO method in land space use planning, which can improve the efficiency and benefit of land space use, and it can be popularized in practical application.