Перегляд за автором "Afanasieva, O. V."

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  • Зображення мініатюри
    Публікація
    Application of Supercontinuum in Optical Gyroscopy
    (Sumy State University, 2023) Kurskoy, Yu. S.; Hnatenko, O. S.; Afanasieva, O. V.
    Робота присвячена вивченню проблеми використання лазерного випромінювання в режимі суперконтинууму у волоконно-оптичних гіроскопах. Для досягнення поставленої мети в роботі вирішувалися наступні завдання: описано фізику процесу вимірювання кутової швидкості об'єкта на основі ефекту Саньяка; проаналізовано фактори, що впливають на роздільну здатність гіроскопа. Ці фактори включають частковий шум, неминучий шум і шум через зворотне розсіювання у волокні, який можна мінімізувати за допомогою фотонно-кристалічних волокон і широкосмугового джерела випромінювання. В якості такого джерела пропонується використовувати оптичний суперконтинуум (оптичну гребінку). Завдяки надширокому спектру випромінювання, точності відтворення частоти, високій стабільності випромінювання та фемтосекундній тривалості імпульсу суперконтинуум вважається перспективним джерелом випромінювання в гіперспектральній спектроскопії та зображенні, томографії та інтерферометрії білого світла з низькою когерентністю. Проведено аналіз можливості використання оптичної гребінки в оптичній гіроскопії. Проведено математичне моделювання впливу характеристик оптичного волокна та параметрів суперконтинууму на чутливість волоконного гіроскопа. Результати роботи свідчать про перспективність подальших досліджень зі створення фотонно-кристалічного волоконно-оптичного гіроскопа з використанням лазерного випромінювання суперконтинууму. The work is devoted to the study of the problem of using laser radiation in the supercontinuum mode in fiber optical gyroscopes. To achieve this goal, the following tasks were solved in the work. The physics of the process of measuring the angular velocity of an object based on the Sagnac effect is described. The factors influencing the resolution of the gyroscope are analyzed. These factors include fractional noise, unavoidable noise, and noise due to backscatter in the fiber, which can be minimized by using photonic crystal fibers and a broadband radiation source. It is proposed to use an optical supercontinuum (optical comb) as such a source. Thanks to its ultra-wide radiation spectrum, precision frequency reproduction accuracy, high radiation stability and femtosecond pulse duration, supercontinuum is considered as a promising radiation source in ranging, hyperspectral spectroscopy and imaging, tomography, and low-coherence white light interferometry. In the work of Lpischan, the physics of the supercontinuum generation process, its main characteristics. An analysis of the possibility of using an optical comb in optical gyroscopy has been carried out. Mathematical modeling of the influence of optical fiber characteristics and supercontinuum parameters on the sensitivity of a fiber gyroscope was carried out. The results of the work indicate the promise of further research on the creation of a photonic crystal fiber-optic gyroscope using supercontinuum laser radiation.
  • Зображення мініатюри
    Публікація
    New Technologies of Laser Hardening of Parts of Fuel Equipment
    (Sumy State University, 2023) Hnatenko, O. S.; Afanasieva, O. V.; Lalazarova, N. O.; Kurskoy, Yu. S.; Odarenko, E. N.; Sashkova, Y. V.; Ivanchenko, O. V.
    Laser thermal hardening of steel (laser hardening) consists in heating a section of the steel surface above the phase transition temperature by laser radiation, followed by rapid cooling due to heat removal. As a result of this treatment, martensite is formed – a saturated solid carbon solution in α-iron. For laser hardening, gas CO2 lasers, solid-state (mainly Nd:YAG) and fiber lasers with a power of 0.5 kW or more are most often used. Optical systems for deploying and scanning the beam allow you to harden large areas of the surface with maximum efficiency. Not all products need processing of significant areas. Measuring and cutting tools, parts of fuel equipment, pump injectors are subject to significant abrasive wear of individual small areas. Less powerful lasers can be used to process them. There are no results of using low power pulsed lasers (up to 20 W) for surface hardening of steel products. The purpose of this work is to determine the modes of surface hardening of parts and tools made of carbon and alloy steels using low power pulsed solid-state YAG lasers. For laser hardening, a solid-state YAG laser with a power of 5 W (diode pumping, radiation wavelength = 1.064 µm, pulsed mode) was used. The use of a nonlinear crystal made it possible to obtain UV radiation from λ = 0.355 µm (third harmonic). Processing with single pulses and multi-pulse processing with short pulses were investigated. Thermal hardening was carried out on carbon and alloy steels of various compositions: 20, 45, У12, Р6M5, Р9, ШХ15, structural and tool steels for the purpose. The possibility of hardening by UV radiation was evaluated on steels 20, 45, У12 and ЩХ15. The efficiency of laser thermal hardening was evaluated by measuring microhardness. For surface hardening of products, where partial melting of the surface is possible, low-power pulsed lasers can be used. Laser hardening by UV radiation is a promising direction for thermal hardening of steels without surface melting. Hardening with a low-power laser is expedient for hardening parts of fuel equipment.
  • Зображення мініатюри
    Публікація
    Physical and Technological Principles of Processing Steel with UV Laser Radiation
    (СумДУ, 2023) Hnatenko, O. S.; Afanasieva, O. V.; Lalazarova, N. O.; Odarenko, E. N.; Sashkova, Y. V.; Ivanchenko, O. V.; Kurskoy, Yu.S.
    The main purpose of the article is to study the hardening of steel using non-standard wavelengths of laser radiation. The physical principles of the interaction of laser radiation with matter are also described. Experiments were carried out on hardening steel with a UV laser (wavelength 355 nm). The following experiments and a comparative analysis of volumetric hardening of steel with cooling in water, hardening with a YVO4 laser beam with (λ = 1.06 μm and hardening with a YVO4 laser beam with (λ = 0.355 μm. The studies were carried out on structural steel 45 and tool steels У12 and Р6M5. In the course of the research, new interesting scientific results were obtained: the study of the microstructure of U12 steel samples using an electron microscope showed that the martensite formed during quenching by UV radiation is more dispersed, as a result of which it can be concluded that such processing can lead to the production of surface nanostructures up to 100 nm in size. However, due to the low productivity and low power of UV radiation, the proposed steel hardening can be recommended for measuring and cutting tools.
  • Зображення мініатюри
    Публікація
    Precision Synchronization of Chaotic Optical Systems
    (CумДУ, 2021) Kurskoy, Yu. S.; Hnatenko, O. S.; Afanasieva, O. V.
    The ideas of this article develop the technologies for synchronization of chaotic information systems components and parameters. Such systems hide information by embedding data into a chaotic carrier signal. Precision chaotic synchronization requires the correct measurement and analysis of chaotic dynamic variables. A model for estimating the degree of synchronization of chaotic laser modes is proposed. The model is based on the principles and methods of nonlinear chaotic values measurement. It provides the measurement and analysis of chaotic variables, the formation of measurement portrait that represents the states and dynamics of the system, and completes the methods for estimating the chaos degree, radiation parameters stability, and degree of synchronization of dynamic variables. A scheme for studying and controlling the chaotic dynamics of pulsed lasers, which includes a laser, a pulsed energy meter, a spectrum analyzer, a pulse frequency measurement unit, and a system for control, synchronization and recording measurement results is proposed. The divergence criteria for the dynamic variables’ values, fractal dimensions, measurement phase? portraits are offered for evaluation of synchronization. The equation that connects the fractal dimension and system parameters stability is obtained. It can be used for control of chaotic information systems components and parameters dynamics.