Перегляд за Автор "Ageev, L.A."

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Optical properties of nanostructures
(Institute for Single Crystals, 2008) Miloslavsky, V.K.; Ageev, L.A.; Makovetsky, E.D.; Maskevich, S.A.
The paper is a brief review of optical properties of nanostructures containing metal nanoparticles. There is a deduction of some simple formulae describing optical spectra of composites containing small particles of various form. Comparison of theoretical and experimental data has been carried out. Conclusions following Mie theory of diffraction on spheres of various diameters and dielectric permittivities are discussed. Various examples of applications of nanoparticles and their influence on surrounding media are given.
Self-diffraction effect observation and recording the holographic one-dimensional and two-dimensional gratings in thin photosensitive films
(Institute for Single Crystals, 2007) Ageev, L.A.; Beloshenko, K.S.; Makovetsky, E.D.; Miloslavsky, V.K.
A setup for observation of the nonlinear self-diffraction effect has been described. A semiconductor laser (P approximately 50mW, wavelength approximately 660nm) is used as a radiation source. The laser beam is divided into two beams by a Wollaston prism, the beams pass through a polarizer and positive lens, then they intersect and create an interference. Using a microscope, the interference may be observed in an increased scale on a remote screen. The interference is registered in a thin photosensitive As2S3-Ag film prepared by vacuum evaporation. We have shown an opportunity to observe the self-diffraction from recorded diffraction grating with linear grooves and from two-dimensional grating induced as a result of second exposure after turning the convergence plane of the interfering beams by 90 degrees.
Spontaneous grating formation in thin light-sensitive AgCl–Ag films at linear P/S-polarization of a laser beam
(Institute of Physics Publishing, 2005) Makovetsky, E.D.; Miloslavsky, V.K.; Ageev, L.A.
We investigated the development of spontaneous gratings arising in light-sensitive waveguide AgCl–Ag films on glass substrates at various cases of linear polarization of the single inducing laser beam. The cause of such a grating development is the appearance of an interference field created by the summation of the incident beam and scattered waveguide TE- and TM-modes. Positive feedback in grating growth is provided by Wood’s anomalies taking place for all the gratings, and the simultaneous development of many microgratings results in their competition. Earlier we found that two-dimensional Bragg’s diffraction seriously affects this competition. This kind of diffraction results in the appearance of secondary dominant gratings. Now we found that at the beam’s polarization, deviated from P-polarization, the appearance of tertiary gratings becomes possible due to the Bragg’s diffraction on secondary dominant gratings instead of this diffraction on primary gratings. The influence of the existence of the first and second steps in two-dimensional diffraction on grating growth is proved by both optical microscopy and complete identification of the modes excited in the substrate and in air (radiative modes in small-angle scattering pattern).
Thermostimulated implantation of nanoscaled Ag particles into a quartz glass using a CO2 laser beam
(Institute for Single Crystals, 2007) Ageev, L.A.; Miloslavsky, V.K.; Makovetsky, E.D.; Beloshenko, K.S.; Stronsky, A.V.
Coloration of fused quartz with colloidal silver (particle radius a ≈ 3 nm) is realized by irradiation of thin (≈ 10 nm) granular Ag film on a quartz plate by a continuous Gauss beam of CO2 laser (λ = 10.6 μm, P = 30 W). Using the AFM microscopy, a relief of the colored surface has been revealed. It is formed by oval lugs with mean transversal size of about ≈ 0.2 μm and heights of several nanometers. The relief is created due to surface deformation caused by subsurface Ag granules. The measured absorption spectrum of the colloid has shown that the absorption band contour is similar to the Lorentz one, maximum being at ω_m = 4.48*10^15 s^(-1), and half-width is γ = 0.714*10^15 s^(-1). Making use of Maxwell-Garnett theory, it has been found that for this colloid, the filling factor is q ≈ 0.05 to 0.10 and coloration depth h ≈ 50 to 100 nm.