The spectral and luminescent properties of quartz glasses, obtained by sintering nanoporous glass matrices and activated with Dy3+ ions, have been investigated. The results of studying the chemical composition and structure of samples with different Dy3+ contents are presented. The range of optimal dysprosium concentration (0.05–0.08 at

The effect of added Al2O3, introduced by the substitution method, on the crystallization and spectral-luminescent properties of gallium germanosilicate glasses with γ-Ga2O3:Ni2+ nanocrystals was investigated. It was found that the Ni2+-luminescence efficiency increased on account of both an increase in the degree of crystallinity of glass with Al2O3 and an increase in the strength of the crystal field around the Ni2+ ions on account of Al3+ incorporation into the structure of the precipitated nanocrystals.

The heat treatment of glasses synthesized in the M 2O-Ga2O3-GeO2-SiO2 (M = Li, Na, K) system results in bulk precipitation of Ga2O3 and LiGa5O8 nanocrystals and, consequently, in luminescence within the bands with maxima at wavelengths of 1500 and 1300 nm, respectively, with the half-width exceeding 300 nm. In their spectral luminescence properties, the gallium germanium silicate glasses synthesized are similar to the gallium silicate glasses. However, the melting temperature of the former glasses is approximately 100°C lower, which considerably facilitates the preparation of glasses of high optical quality.

The shape of the fundamental OH stretching band of GeO2 glass was analyzed before and after hydrostatic compression at 5.2 GPa. The results were interpreted using quantum-chemical modeling of the incorporation of OH groups and H2O molecules into the GeO2 glass network.

The threshold intensities of the radiation required for sustaining the optical discharge waves in various silica fibres for different wavelengths of laser radiation are measured. It is shown that over a wide range of experimental conditions, the threshold intensity is determined mainly by the diameter of the mode field in the fibre. The destruction of chalcogenide and fluoride fibres upon exposure to laser radiation of power ~ 1 W is studied for the first time. The optical discharge wave is not formed in such fibres, and the destruction occurs due to thermal decomposition of the fibre material over the entire cross section of the fibre. The destruction of these fibres is characterised by much lower threshold intensities of laser radiation than in the case of silica fibres.

The absorption and luminescence spectra of silica fibres doped with chromium and various dopants are studied. Fibres doped with aluminium and gallium exhibit a broad (300 nm) luminescence band of Cr4+ ions at 1100 nm at room temperature. The quantum yield of luminescence is estimated to be 10(-4) - 10(-5).

Single-mode optical fibres were fabricated from a germanosilicate glass by the method of modified chemical vapour deposition (MCVD), which used sintering of a porous glass in a reducing (helium or nitrogen-containing) atmosphere, The optical fibres exhibit a high photoinduced change in the refractive index and a high efficiency of recording quadratic nonlinear susceptibility compared to a standard germanosilicate fibre. Sintering, both in nitrogen and in helium atmospheres, was shown to increase the concentration of germanium oxygen-deficient centres in glass. It is likely that nitrogen enters into a germanosilicate glass in the concentration that is sufficient to modify the glass structure and to additionally increase its photosensitivity. The replacement of oxygen or silicon in the close vicinity of an oxygen vacancy by nitrogen may play a key role in the photosensitivity enhancement owing to the formation of additional valence bonds and blocking of recombination processes.

UV laser irradiation and hydrostatic compression of germanosilicate glass resulted in different changes in the glass structure. Modifications of the glass structure by UV irradiation were localised near dissociated germanium oxygen-deficient centres. Destruction of these defects was assumed to stimulate formation of threefold rings containing Ge — O — Ge bonds.

An investigation was made of changes in the Raman spectra of germanosilicate optical fibres as a result of UV irradiation. The photoinduced changes in the spectra were of the same nature for all types of irradiation used. These changes increased with increase in the radiation dose and in the GeO2 concentration in the fibre core and were evidence of a structural modification of glass.

The method of distillation in a jet formed by cw CO2 laser radiation of ~100 W power was used in synthesis of copper-doped silica glass samples. A silica target in the form of a tube with a diameter of 2.6 or 1.2 mm, containing a copper wire, was employed. A scanning electron microscope and an x-ray microanalyser were used in an investigation of the characteristics of the microstructure of the samples and of the spatial distribution of the impurity concentration as a function of the position of the deposition zone in the laser jet. A study was made of the absorption and luminescence spectra of a cylindrical sample, ~5 mm in diameter, grown in the core of a gasdynamic jet. The results showed that the glassy phase consisted of the SiO2:Cu0n composite.

The radiation features of a selection of silica and polymer fibers were investigated. Silica fibers with a high-OH-content core demonstrated a radiation hardness of similar to 6-10 Mrad/m in the ultraviolet wavelength range (lambda = 337 nm). The fibers partially recovered their optical properties at room temperature and completely recovered them on heating to 300 degrees C. It was found that the radiation hardness of fragile polymer fibers was similar to 300 times less than that of normal ones.