Перегляд за автором "Dzubenko, M. I."

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  • Зображення мініатюри
    Публікація
    Coaxial Laser Resonator with Smooth Adjustment of Radiation Output
    (Begell House, 2020) Dzubenko, M. I.; Maslov, V. A.; Odarenko, E. N.; Radionov, V. P.
    A new design of a laser resonator with smooth adjustment of radiation output is presented. Adjustment can be performed over a wide range and directly during laser operation. This provides optimal feedback under various laser operating conditions. The active element has an annular sectional shape. The pumping and cooling elements can be placed on the outer and inner sides of the active element. This ensures a uniform distribution of pump energy and good heat dissipation from the active substance. Gaseous, liquid and solid substances can be used as an active medium. The possibility of obtaining optimal feedback and homogeneity of the active substance make it possible to increase the efficiency of laser generation. Coaxially arranged conical mirrors provide a rational change in the radiation path in the cavity. The radiation makes a complete passage through the cavity in four different ways. This allows to minimize the effect of inhomogeneities of the active substance on the radiation, which improves the spatial-angular and energy characteristics of the output laser radiation. Conical 90° mirrors that are used in the laser cavity do not require careful alignment and provide increased laser stability. Such a resonator scheme is suitable for use in a wide frequency range, including the terahertz range.
  • Зображення мініатюри
    Публікація
    Sectional Circular Gradient Grating with Improved Focusing Characteristics in THz Frequency Range
    (IEEE, 2020) Dzubenko, M. I.; Radionov, V. P.; Maslov, V. A.; Odarenko, E. N.
    A method for increasing the focusing properties of annular gradient gratings is presented in this work. The interaction of the coherent radiation of the terahertz range with gradient gratings consisting of concentric metal rings is investigated. The thickness and width of the metal rings is much less than the radiation wavelength. The distance between the rings varies in the radial direction, but does not exceed half the wavelength. It was previously found that such planar structures have focusing properties. Moreover, they can simultaneously serve as a concave mirror and a focusing lens. The combination of these properties is promising for laser output mirrors. This makes it possible to reduce diffraction losses in the laser cavity and improve the spatial and angular characteristics of the laser beam. In addition, laser radiation acquires azimuthal polarization, which has certain advantages. In some cases, an increase in the focusing properties of gradient gratings is required. A significant increase in focusing properties can be achieved by sectioning according to the principle of Fresnel lenses. However, phase inhomogeneities arise at the boundaries of the sections. This disrupts focus and introduces additional loss. In the work, a method for increasing the focusing properties of sectioned circular gradient gratings by giving them a stepped shape is considered. The results of modeling such gratings are presented.