Voronezh State University

About: Voronezh State University is a education organization based out in Voronezh, Russia. It is known for research contribution in the topics: Silicon & Boundary value problem. The organization has 5166 authors who have published 6097 publications receiving 31680 citations. The organization is also known as: VSU & Voronezh University.

Low- and high-order nonlinear optical studies of ZnO nanocrystals, nanoparticles, and nanorods

Abstract: Variable shapes and sizes of the zinc oxide nanostructures attract the attention due to the peculiarities of their nonlinear optical properties. We report the second-, third-, and high-order nonlinear optical studies of ZnO nanostructures using 800 nm, 40 fs pulses. We analyze the second harmonic generation as a function of the energy of the 800 nm laser pulses irradiating ZnO nanostructures. The studied samples possess the quadratic dependence of the second harmonic yield at the variable intensity of laser radiation. The Z-scan studies of ZnO nanoparticles suspension using 400 nm probe pulses allow determining their nonlinear refractive index (4 × 10−11 cm2 W−1) and nonlinear absorption coefficient (8 × 10−7 cm W−1). We also analyze the optical limiting properties of ZnO nanoparticles suspension. The propagation of femtosecond pulses through the plasmas containing ZnO nanoparticles allowed generation of high harmonics up to the 29th order.

Photostimulated Formation of Sensitized Anti-Stokes Luminescence Centers in AgCl(I) Microcrystals

Abstract: The low-temperature photostimulated activation of sensitized anti-Stokes luminescence in heterogeneous systems based on AgCl(I) microcrystals with adsorbed organic dye molecules and their aggregates is investigated. It is shown that the observed considerable (by more than an order of magnitude) enhancement of the intensity of this luminescence is caused by the formation of silver atoms and few-atom clusters on the surface of AgCl(I) microcrystals, which increase the efficiency of a two-quantum excitation of sensitized anti-Stokes luminescence by optical radiation in the range 630–730 nm with the flux density 1013–1015 quantum cm−2s−1. Analysis of all the experimental results indicates that the excitation mechanism of anti-Stokes luminescence is based on successive electron transfer or electron-excitation energy transfer from a dye molecule to an atomic-molecular dispersive silver center.

Method of clonal micropropagation of different willow species and hybrids

Abstract: Conditions of cultivation and micropropagation of selected biotypes of five willow species (Salyx dasyclados Wimm., S. caspica Pall., S. triandra L., S. purpurea L., and S. viminalis L.) and two hybrids (×S. acuminata S. and ×S. palustris Host.) were optimized. Data on in vitro propagation of S. caspica, S. triandra, S. purpurea together with hybrids S. acuminata and S. palustris were obtained for the first time. It has been demonstrated that the outcome of cultivation and propagation of willows strongly depends on genotypic peculiarities of initial plants. The optimal terms of isolation and sterilization of single-node segments for obtaining 50–75% of aseptic viable developing cultures were estimated. The nutritive media were selected providing induction of stem development (to 67%), their rooting (to 91%), elongation (to 3–6 cm), and multiplication (propagation coefficient of 4). The designed method (adopted to different genotypes) can be applied for obtaining aseptic in vitro cultures serving as initial plant material for genetic transformation and mass propagation of plants with new agriculturally valuable characteristics which are of interest for construction of bioenergetic plantations and for needs of the paper industry.

Nonlinear Optical Properties of Hybrid Associates of Azure A Molecules with Zn0.5Cd0.5S Colloidal Quantum Dots

Abstract: We present the results of the study of the nonlinear optical response observed in hybrid associates of Azure A dye with Zn0.5Cd0.5S colloidal quantum dots upon exposure to 10-ns pulses of the second harmonic (532 nm) of a Nd3+:YAG laser. It is shown that association enhances the absorption saturation in the dye by a factor of 4.5, which is caused by charge phototransfer between the components of the hybrid associate.