G. F. Kostyuk

Bio: G. F. Kostyuk is an academic researcher from Samara National Research University. The author has contributed to research in topics: Diamond & Anti-reflective coating. The author has an hindex of 3, co-authored 3 publications receiving 54 citations.

Formation of diffractive microrelief on diamond film surface

Abstract: The fabrication of diamond-based optical elements for high-power CO2 lasers is of particular interest because of low optical absorption, high thermal conductivity and weak temperature dependence of the refractive index of diamond. In earlier publications, we presented the results of the implementation of ion-chemical etching technology for generating a diffraction grating on the surface of a diamond film. The results on generating diamond diffractive optical elements and a sub-wavelength antireflection structure by plasma etching were also presented. In this paper, we study the generation of the grating on the diamond surface by ion-chemical etching. The choice of (Ar+O2) mixture as a working gas and use of niobium as a masking layer are substantiated. The results of studying a diffraction microrelief generated on the diamond-film surface through ion-chemical etching are discussed.

Synthesis and Investigation of Diamond Diffractive Optical Elements

Abstract: The fabrication of diamond-based optical elements for high-power CO 2 lasers is of particular interest because of the low optical absorption coefficient of this material in combination with its very high thermal conductivity and the weak temperature dependence of refractive index. Recent advances in gas-phase synthesis have made it possible to fabricate polycrystalline CVD diamond films (DF) whose optical and thermal properties are close to those of single crystal diamond material, whereas they are far cheaper. As a result, these sophisticated materials are applied more and more to tasks dominated till now by other materials. Such examples for this are windows for high-power CO 2 lasers in the 5 - 20 kW domain 1 and beam-splitters 2 . Recently new techniques have been proposed for antireflective structuring of DF surface 3,4 as well as for generation of phase microrelief to manufacture diamond diffractive optical elements (DOEs) for the far IR range 5-8, 10 . The realisation of DOE by UV-laser ablation has been considered 5-8 . Using of ion-chemical etching 9 and plasma etching10 is considered later. The present paper is devoted to further development of considered approaches 5,9 . The realization of diamond diffractive optical elements (DOEs) is considered, able to focus an incoming CO 2 laser beam into certain pregiven focal domains. Results of experimental investigation of designed DOEs are presented and discussed.

Synthesis of diamond diffractive optical elements for IR laser beam focusing

Abstract: The fabrication of diamond-based optical elements for high-power CO 2 lasers is of particular interest because of the low optical absorption coefficient of this material in combination with it's very high thermal conductivity and the weak temperature dependence of refractive index 1 . Recent advances in gas-phase synthesis have made it possible to fabricate polycrystalline CVD diamond films (DF) whose optical and thermal properties are close to those of single crystal diamond material, whereas they are far cheaper. As a result, these sophisticated materials are applied more and more to tasks dominated till now by other materials. Such examples for this are windows for high-power CO 2 lasers in the 5 - 20 kW domain 1 and beam-splitters 2 . Recently new techniques have been proposed for antireflective structuring of DF surface 3,4 as well as for generation of phase microrelief to manufacture diamond diffractive optical elements (DOEs) for the far IR range 5-8 . The realisation of DOE by UV-laser ablation has been considered 5-8 . Using of ion-chemical etching and plasmochemical-etching 9 is considered later 10 . The present paper is devoted to further development of considered approaches 5,9 . The realization of diamond diffractive optical elements (DOEs) is considered, able to focus an incoming CO 2 laser beam into certain pregiven focal domains. Results of experimental investigation of designed DOEs are presented and discussed.

Formation of nanoporous structures in metallic materials by pulse-periodic laser treatment

Abstract: A method of the formation of nanoporous structures in metallic materials by pulse-periodic laser treatment was developed. In this study, the multicomponent aluminum–iron brass was considered and the nanoporous structure across the entire cross section of the material with a thickness of 50 µm was formed. The method was implemented using a CO2 laser processing unit. The pulse-periodic laser treatment of the Cu–Zn–Al–Fe alloy with pulse frequency of 5 Hz has led to the formation of nanosized cavities due to accumulation of internal stresses during cyclic heating and cooling at high speeds. It was determined that the pores of a channel type with average widths of 80–100 nm are formed in the central region of the heat-affected zone during laser action with thermocycling. When implementing the chosen conditions of the pulse-periodic laser processing, the localness in depth and area of the physical processes occurring in the heat-affected zone is ensured, while maintaining the original properties of the material and the absence of significant deformations in the rest of the volume. This patented process is perspective for the production not only catalysts for chemical reactions, but for ultrafiltration and microfiltration membranes as well.

Analysis of the Advantages of Laser Processing of Aerospace Materials Using Diffractive Optics

Abstract: We considered possibilities of an application of diffractive free-form optics in laser processing of metallic materials in aerospace production. Based on the solution of the inverse problem of heat conduction, an algorithm was developed that calculates the spatial distribution of the power density of laser irradiation in order to create the required thermal effect in materials. It was found that the use of diffractive optics for the laser beam shaping made it possible to obtain specified properties of processed materials. Laser thermal hardening of parts made of chrome–nickel–molybdenum steel was performed. This allowed us to increase the wear resistance due to the creation in the surface layer of a structure that has an increased hardness. In addition, a method of laser annealing of sheet materials from aluminum–magnesium alloy and low-alloy titanium alloys was developed. Application of this method has opened opportunities for expanding the forming options of these materials and for improving the precision in the manufacturing of aircraft engine parts. It was also shown that welding by a pulsed laser beam with a redistribution of power and energy density makes it possible to increase the strength of the welded joint of a heat-resistant nickel-based superalloy. Increasing the adhesion strength of gas turbine engine parts became possible by laser treatment using diffractive free-form optics.

Лазерная сварка разнородных металлических материалов с использованием дифракционных оптических элементов

Abstract: A use of laser technology it is progressive in the welding of dissimilar materials. Pulsed laser welding of an aluminum alloy AK4 and a titanium alloy VT5-1 was performed. Processing conditions were determined, the realization of which during melting of materials in the heat-affected zone makes it possible to obtain a homogeneous structure without voids and shells, potentially producing sufficiently sound welded joints. To create the required power density distribution across the laser beam, it was found expedient to use diffractive optical elements. Aluminum and copper were welded by continuous laser beam. It is determined that laser action with its welldefined and precise localized heat input makes it possible to significantly reduce the growth of intermetallic compound layers.