http://dspace.nbuv.gov.ua:80/handle/123456789/114621 2026-04-12T17:12:20Z 2026-04-12T17:12:20Z Baschenko, S.M. http://dspace.nbuv.gov.ua:80/handle/123456789/121237 2017-06-14T00:07:46Z 2000-01-01T00:00:00Z

Advanced modification of main types of excimer laser resonators Baschenko, S.M. In the paper proposed are some simple modifications of plane-parallel and unstable telescopic resonators the most widely used in excimer lasers. These can increase output energy, density of emission power and improve the shape of a laser beam cross-section. Physical essence of these modifications lies in formation of an optically closed zone in some part of the resonator, which prevents photons to escape. This yields in their increased concentration (the so-called `photon concentrator') that favors discharge stabilization and shifting this zone towards a cathode where main instabilities of an electric discharge originate. In the plane-parallel cavity such a photon concentrator can be realized by application of an output window with a mirror area in the range corresponding to the cathode space. Using the scheme in our conditions we observed the increase of laser pulses emission energy by 15% and, respectively, their energy density by 44% with simultaneous decreasing the laser beam shape extent (in its cross-section) and proportional reducing a beam divergency along the diminished size. In the unstable telescopic resonator this kind of a closed zone (photon concentrator) should exist by definition and, as a rule, in a paraxial part of it. The modification proposed consists in shifting this zone towards a cathode. In our conditions this way provided the increase of laser pulse emission energy by 5% with simultaneous improvement of the laser beam shape (in its cross-section). It means shifting a shaded spot towards a border of the beam cross-section and, in such way, to its practical removal out of operating beam.

2000-01-01T00:00:00Z Kruglenko, I.V. Snopok, B.A. Shirshov, Y.M. Venger, E.F. http://dspace.nbuv.gov.ua:80/handle/123456789/121235 2017-06-14T00:06:47Z 2000-01-01T00:00:00Z

Digital aroma technology for chemical sensing: temporal chemical images of complex mixtures Kruglenko, I.V.; Snopok, B.A.; Shirshov, Y.M.; Venger, E.F. The reliability of Electronic nose applications is mainly based on the sensitivity, repeatability and discernment properties of the sensors composing the array. Due to nature of the chosen sensitive layers, the sensors are particularly suitable to classify environments in which compounds with various chemical functionality play a key role. This article is focusing on the novel strategy aimed at the improving the quality and quantity of chemical information from the sensing instruments based on incorporation kinetic aspects of the array response for perfect formation and improved discrimination of chemical images of the probes. We describe a procedure for reducing both time response and number of elements of gas sensor arrays based on principal component analysis (PCA). Thus, digital aroma technology may be used not only as background for formation of chemical images using intelligent sensor massifs but as well as effective experimental tools for characterization and selection coatings with desired chemical functionality by using time-resolved pattern recognition.

2000-01-01T00:00:00Z Kravets, V.G. Vinnichenko, K.L. Prygun, O.V. http://dspace.nbuv.gov.ua:80/handle/123456789/121234 2017-06-14T00:07:37Z 2000-01-01T00:00:00Z

Characterization and optical properties of organic dye films as recording media Kravets, V.G.; Vinnichenko, K.L.; Prygun, O.V. Efficiency of medium choice for optical information recording is generally determined by homogeneity degree of material on the recording surface and by its structure on the film depth. In this respect pyrosolynes should be the prospective materials. Pyrosolyne dye films were produced on the glass substrates initially remained at room temperature T = 20°C by using different techniques such as vapor deposition and sol-gel modified reactions. One of the precise control methods of material surface physical-chemical state is ellipsometric method. In addition, the optical transmission measurements were carried out for these films within the wavelength range λ = 200-630 nm at two different polarization (p- and s-) of the incident light. It has been shown that the absorption bands near n = 1300 cm⁻¹ are present in ellipsometric parameters spectra in case of the vapor deposited dye film samples. The transmission optical measurements of organic films in the visible range without polarizer showed presence of the absorption bands near λ = 300 and 520 nm. The first absorption band was much more intensive than another. It has been determined that the transmission values measured in polarized in p- and s-directions light differs by 5-8% in comparison with data measured without polarizer.

2000-01-01T00:00:00Z Alexeyev, C.N. Soskin, M.S. Volyar, A.V. http://dspace.nbuv.gov.ua:80/handle/123456789/121231 2017-06-14T00:07:21Z 2000-01-01T00:00:00Z

Spin-orbit interaction in a generic vortex field transmitted through an elliptic fiber Alexeyev, C.N.; Soskin, M.S.; Volyar, A.V. Any small external perturbation on an ideal round optical fiber induces cross - section deformation and transforms eigen guided vortices into generic vortex fields, which can change their structure and angular momentum. It is the properties of these vortical fields in an elliptic weakly guiding optical fiber that we consider in this paper. The eigenfunctions and the spectrum of polarization corrections to the scalar propagation constant in the case of relatively large and small values of a fiber ellipticity are obtained by means of the spin-orbit interaction operator method. Discussed is the conversion process of a spin and orbit angular momenta on a vortex propagation along a deformed fiber.

2000-01-01T00:00:00Z