SIGNAL PROCESSING AND CYBERSECURITY IN SOME CHAOTIC OPTICAL COMMUNICTAION SYSTEMS

A chaos –geometric approach to investigation of complex chaotic dynamical systems is applied to an analysis, modeling and processing the time series of emission intensities of chaotic transmitter/receiver systems (two unidirectionally coupled semiconductor laser systems in the all-optical scheme) suited for encoding at rates of GBit/s. the problem of a signal processing is directly connected with the corresponding cybersecurity in some optical chaos communictaion systems. The estimated values for the dynamic and topologic invariants such as the correlation and Kaplan-York dimensions, Lyapunov indicators, Kolmogorov entropy etc for investigated chaotic signal time series of two unidirectionally coupled semiconductor laser systems in the all-optical scheme.

Optical system design of multispectral video camera for 8-14 microns range

To solve the actual problem of determining the composition of a gas mixture in an uncontrolled leak at industrial sites, it is proposed to use a multispectral camera that allows you to simultaneously form several spectral images on a bolometric matrix. This method will provide visualization of the gas cloud in the far infrared range from 8 to 14 micrometers with selection by chemical composition. The article proposes an optical scheme for simultaneous registration of images in eight narrow spectral ranges of wavelengths, as well as the design of its elements for a bolometric matrix with a resolution of 640x480 pixels: a lens, a raster, and light filters using the ZEMAX application software package. As a result of the design, a low F-number three-lens optical system for a necessary field of view and a raster with a block of light filters are obtained, forming sixteen images in different spectral ranges. Thus, we solved an issue of design an optical system with minimal aberrations for a multispectral camera.

Development of a selective assembly card of the «Koadut» lens

The work is devoted to the development of a selective assembly card of the «Koadut» lens, depending on the actual thickness of each of the seven lenses included in the optical scheme of the objective. Criteria for sorting options are substantiated, a macro for processing a file with the results of measurements of actual lens thicknesses, which forms an assembly card, is created. The macro was tested on a test file with a normal distribution of deviations from the nominal value of a batch of one hundred lenses.

Optical telescope with 3.75 ◦ field of view and pre-aperture slewing mirror with observation area of 50 ◦ ×120 ◦ for the system of observation of day time asteroids (the SODA project)

В работе предложена оптическая схема широкоугольного телескопа с полем зрения 3.75 ◦ и апертурой 30 см для космической системы обнаружения декаметровых астероидов (проект СОДА). Основная отличительная особенность телескопа - наличие предапертурного плоского зеркала, обеспечивающего область наведения 50 ◦ × 120 ◦ , время перенаведения между соседними площадками составит не более 3 с. Предложен современный КМОП детектор с мелким пикселем. В работе представлены области обзора телескопов проекта СОДА из точки Лагранжа L 1 при использовании двух, трех и четырех телескопов, кратко обсуждены преимущества и недостатки каждого из вариантов. We propose an optical scheme of a telescope with a field of view of 3.75 ◦ and 30 cm aperture for the space system for observation of decameter size asteroids (the SODA project). The main distinctive feature of this telescope is a pre-aperture flat mirror that provides an observation area of 50 ◦ ×120 ◦ and a repointing time between the adjacent fields of less than 3 s. A modern CMOS detector with a small pixel is proposed. Observable sky area when using 2, 3 and 4 telescopes are described. The advantages and disadvantages of each option are briefly discussed.

Performance of Optical Mobile Communications with User Mobility and Multiple Light Sources

Optical mobile communication (OMC) is a recently proposed optical wireless communication concept aiming to provide very high-speed data rate optical wireless links for multiple and, in general, distributed mobile users. Previous work analyzed the rate performance of a two-user OMC system without user mobility. This paper extends the rate analysis to multiple users with mobility. The scenario of employing multiple light sources with possible user grouping is also considered. User mobility and multiple light sources lead to new challenges on the system design which are addressed for broadcast downlink communication in this work. Simulations show that user mobility decreases the rate, and the way of how to utilize multiple light sources has great impact on the performance. In particular, simultaneous power division usage of multiple light sources through user grouping and power allocation brings almost no gain as compared with the case of single light source. On the other hand, time division usage of multiple light sources is capable of compensating for the hardware deficiency and thus increasing the rate greatly. It is found that OMC is not only superior to the conventional scheme with nonadjustable channel gains but also outperforms free space optical scheme at high signal-to-noise ratio region.

Fast Optical Investigation of Cardiac Electrophysiology by Parallel Detection in Multiwell Plates

Current techniques for fast characterization of cardiac electrophysiology employ optical technologies to control and monitor action potential features of single cells or cellular monolayers placed in multiwell plates. High-speed investigation capacities are commonly achieved by serially analyzing well after well employing fully automated fluorescence microscopes. Here, we describe an alternative cost-effective optical approach (MULTIPLE) that exploits high-power LED arrays to globally illuminate a culture plate and an sCMOS sensor for parallel detection of the fluorescence coming from multiple wells. MULTIPLE combines optical detection of action potentials using a red-shifted voltage-sensitive fluorescent dye (di-4-ANBDQPQ) with optical stimulation, employing optogenetic actuators, to ensure excitation of cardiomyocytes at constant rates. MULTIPLE was first characterized in terms of interwell uniformity of the illumination intensity and optical detection performance. Then, it was applied for probing action potential features in HL-1 cells (i.e., mouse atrial myocyte-like cells) stably expressing the blue light-activatable cation channel CheRiff. Under proper stimulation conditions, we were able to accurately measure action potential dynamics across a 24-well plate with variability across the whole plate of the order of 10%. The capability of MULTIPLE to detect action potential changes across a 24-well plate was demonstrated employing the selective Kv11.1 channel blocker (E-4031), in a dose titration experiment. Finally, action potential recordings were performed in spontaneous beating human induced pluripotent stem cell derived cardiomyocytes following pharmacological manipulation of their beating frequency. We believe that the simplicity of the presented optical scheme represents a valid complement to sophisticated and expensive state-of-the-art optical systems for high-throughput cardiac electrophysiological investigations.