Formation and Self-arrangement of Nanocomposite Materials via Glass Anneal in Hydrogen

The process of metal nanoparticles formation in glass during its annealing in hydrogen is studied. On the basis of phase transition theory the strict system of equations describing this process is developed and simulated. The simulation shows that the system has two qualitatively different solutions: continuous distribution of nanoparticles in bulk glass and Liesegang-like layers. The results of the numerical modeling agree well with known experimental data: both types of the distributions have been registered in experiments. The dependence of final nanoparticles distribution on system parameters (initial concentrations diffusion coefficients) has been analysed. When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/3479

Glass-metal nanocomposite modification by femtosecond laser irradiation

Modification on silver nanoparticles (AgNPs) is of interest for various nonlinear optics applications and optical data storage. Femtosecond laser modification allows elongation of spherical AgNPs [1]; these elongated particles possess intrinsic anisotropy [2], which results in dichroism [3]. Here we present the study of transmissivity and reflectivity of glass-metal nanocomposites (GMN) [4] irradiated with 330 fs laser pulses at 515 nm wavelength; the GMN was fabricated using technique based on ion-exchange [5]. The laser processing of the NP results in the dichroism exhibited in optical spectra of transmission and reflection. At higher energies we observed the increase of transmittance and decrease of reflectance, which is attributed to dissolution of NP into the glass lattice

Revealing the nanoparticles aspect ratio in the glass-metal nanocomposites irradiated with femtosecond laser

We studied a femtosecond laser shaping of silver nanoparticles embedded in soda-lime glass. Comparing experimental absorption spectra with the modeling based on Maxwell Garnett approximation modified for spheroidal inclusions, we obtained the mean aspect ratio of the re-shaped silver nanoparticles as a function of the laser fluence. We demonstrated that under our experimental conditions the spherical shape of silver nanoparticles changed to a prolate spheroid with the aspect ratio as high as 3.5 at the laser fluence of 0.6J/cm2. The developed approach can be employed to control the anisotropy of the glass-metal composites

Ion-exchange-induced formation of glassy electrooptical and nonlinear optical nanomaterial

Subsurface electrooptical glass-ceramic layers are formed in an alkaline-silica-niobate glass using ion exchange technique. Ways of selection of glass compositions and ion exchange conditions to form such layers are discussed. It is shown that there are two ways to form glass-ceramics; the first one is the glass ceramization during the ion exchange treatment at higher temperatures, and the second one is the glass ceramization in heat treatment of the samples ion exchanged at lower temperatures, at which glass crystallization does not take place. The latter allows producing glass-ceramics layers of controllable thickness, because in this case diffusion process strongly obeys Fick equation

Optical waveguides in electrooptical nanophase glass-ceramics

Optical wave guides in glass-ceramics, demonstrating a high Kerr coefficient, are studied. The waveguides were produced by an ion exchange technique applied to glass-ceramics formed by controllable glass crystallization under heat treatment

Fluorophosphate glasses doped with PbSe quantum dots and their nonlinear optical characteristics

A new fluorophosphate glass matrix containing PbSe quantum dots characterized by a narrow size distribution (Delta R/R similar to 5-7%, where R is the size of a quantum dot) is prepared under heat treatment. It is demonstrated that fluorophosphate glasses can be doped by introducing (ZnSe + PbO) or PbSe into the composition of the glass. The optical absorption spectra of the quantum dots corresponding to the strong quantum confinement regime are studied over a wide range of quantum-dot sizes (4-18 nm). The nonlinear optical absorption is investigated at a wavelength of 1.54 mu m. It is revealed that the introduction of (ZnSe + PbO) rather than of PbSe into the composition of the glass improves the bleaching contrast owing to a more uniform distribution of the quantum dots over the volume of the glass sample

Kerr studies of several tellurite glasses

International audienceEstimates of Kerr electrooptical sensitivity of several tellurite glasses are presented. The highest value of Kerr coefficient B 190 1016mV2 is registered for 0.6TeO2–0.3TlO0.5–0.1ZnO glass. This evidences the prospects of thallium–tellurite glass system for electrooptical applications. A gradual decrease of B from 41 1016 to 26 1016mV2 in (1 x) TeO2 – xNbO2.5 system is revealed for x increasing from 0.1 to 0.15. No crystalline phase was found in that system, thus allowing attributing its Kerr sensitivity to the intrinsic properties of the glass matrix. The Kerr coefficient variation from 66 to 81 1016mV2 was observed for 0.85TeO2–0.15WO3 glasses co-doped with small amounts of silver and cerium. The analysis of optical absorption spectra of several silver-containing tellurium–tungsten oxide glasses makes it possible to think that introducing cerium provokes formation of new mid-range orderings

Revealing the nanoparticles aspect ratio in the glass-metal nanocomposites irradiated with femtosecond laser

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