V. I. Arbuzov

Effect of Coloring Impurities on the Absorption in Neodymium Phosphate Laser Glass at a Lasing Wavelength

This paper reports on the results of the investigation of KGSS 0180/35 neodymium phosphate glasses produced on an industrial scale under oxidizing conditions and glasses prepared under experimental conditions in which iron and copper in small amounts rather than neodymium are introduced into the glass composition. The experimental glasses are synthesized by varying the redox conditions of melting. The oxidation states of transition metal impurities (Cu, Fe, V, Ni, Co) and the nonactive absorption coefficients of glasses at the lasing wavelength are determined. It is revealed that the main contribution to the nonactive absorption coefficient of the KGSS 0180/35 glass produced on an industrial scale is made by Cu2+ ions at a concentration higher than 0.5 ppm. At a lower copper concentrations, the total contribution of Fe2+, V4+, Ni2+, and Co2+ impurity ions to the nonactive absorption coefficient is comparable to that of Cu2+ ions. It is demonstrated that a decrease in the concentration of coloring impurities in glasses and the optimization of redox conditions of melting make it possible to prepare phosphate laser glasses with a nonactive absorption coefficient of the order of 0.001 cm−1. In terms of the nonactive absorption coefficient, these glasses are on a par with similar glasses of foreign manufacture and satisfy the requirements imposed on glasses by developers of high-power high-energy laser facilities.

Influence of the redox conditions of melting on the quantitative ratio of ions Fe2+/Fe3+ in aluminum potassium barium phosphate glass

This paper reports on the results of the investigation of the KGSS 0180 phosphate laser glasses produced under industrial conditions, in which iron is contained in the form of impurities, and the glasses prepared under laboratory conditions with iron additives and a composition similar to that of the KGSS 0180 glass matrix. The influence of the redox conditions of glass melting on the quantitative ratio of ions Fe2+/Fe3+ in the glass composition and on the contribution of Fe2+ ions to the inactive absorption coefficient at the lasing wavelength (1.053μm) is analyzed.

How process factors affect the limiting characteristics of neodymium phosphate glasses for large disk- and rod-shaped active elements

This paper lists the requirements imposed by the designers of powerful high-energy lasers and radiation amplifiers on KGSS 0180 phosphate glasses with various neodymium concentrations, used to manufacture large disk- and rod-shaped active elements. The classical two-stage technology for melting them is described, and a quantitative characterization is given of the extent to which structural water and the neodymium concentration in the glasses affect the maximum achievable luminescence time and quantum yield. A description is given of why inactive absorption of radiation appears at the lasing wavelength and a method for reducing it in the resulting glasses. A method is indicated for reducing the number of inclusions of metallic platinum in the glass, which affect its radiation strength.

Influence of the melting temperature and rate of cooling the melt to the glass making temperature on the redox equilibria Fe2+ ⇄ Fe3+ and Cu+ ⇄ Cu2+ in aluminum potassium barium phosphate glasses

This paper reports on the results of the investigation of aluminum potassium barium phosphate glasses that contain copper and iron additives and have compositions similar to the composition of the matrix of the KGSS 0180/35 neodymium phosphate glass used for fabricating large-sized active elements intended for high-power laser amplifiers with a high output energy. The redox equilibrium of iron ions has been studied as a function of the melting temperature of the glass (850, 1100, and 1300°C). The redox equilibrium of iron or copper ions and their contributions to the nonactive absorption coefficient of glasses prepared at the melting temperature (1100°C) or after cooling of the glass melt at different rates to the glass making temperature (850°C) have been investigated. It has been established that a decrease in the melting temperature of the glass leads to a shift in the redox equilibrium of iron ions toward the formation of Fe3+ ions. During cooling of the glass melt from 1100 to 850°C, the redox equilibrium of copper (iron) ions shifts toward the formation of Cu2+ (Fe3+) ions; in this case, the lower the rate of cooling the melt, the larger the shift. At the minimum rate of cooling the glass melt (250°C for 180 min), the contribution of copper ions to the nonactive absorption coefficient increases by 25%, whereas the corresponding contribution of iron ions decreases by 40%.

Large disc-shaped active elements made from neodymium phosphate glass elements made from neodymium phosphate glass

A technology has been developed for the production of large active elements made from KGSS 0180/35 neodymium phosphate glass (with a neodymium ion concentration of NNd53.5 x1020cm-3), iintended for powerful pulsed lasers with high output radiation energy. The neodymium glasses were melted using a two-stage or single-stage process with high-purity reagents in crucibles made from dispersion-strengthened platinum or a newly developed highstrength cristobalite refractory, which, along with other process methods, makes it possible to obtain glass that contains no metallic platinum inclusions. The main elements of the process for synthesizing neodymium glass are deep oxidation of the melt with dry oxygen in order to convert traces of platinum and iron to higher valence states and simultaneously eliminate hydroxyl group impurities, as well as the use of a nonplatinum refractory to fabricate the glassware. The resulting glasses are characterized by high optical homogeneity, high luminescence lifetime of the neodymium ( t~300 us), radiation strength to 33 J/cm2 when the exciting pulse width is 3?4 ns, and a nonactive absorption coefficient at the lasing wavelength of about 0.0015 cm-1. The required high-quality surface processing of the active elements is provided by fine annealing of the blanks and by using grinding?polishing equipment with program control.

The special aspects of neodymium and copper-containing phosphate glasses production for large-scaled disk active elements of power high-energy lasers and radiation amplifiers

The necessity of creating the power high-energy radiation amplifiers requires the production of increasingly large disk active elements (DAE). Increasing the size of the required DAE leads to certain problems while their multistage production. Some of them, primarily related to the terms of melting were reviewed.

Neodymium- and copper-bearing phosphate glasses for fabricating large rod-shaped and disk-shaped active elements of lasers and heavy-duty high-energy radiation amplifiers

This paper analyzes the requirements imposed on laser glasses intended for the fabrication of rod-shaped and large disk-shaped active elements with a large aperture for generators and heavy-duty radiation amplifiers. Quantitative data are presented concerning the maximum achievable values of the functionally important basic characteristics of domestically produced neodymium phosphate glasses and the copper-oxide-doped glasses from which absorbing shells (cladding) are fabricated that suppress superluminescence and stray lasing in disk-shaped active elements.

Calculating the quantitative characteristics of x-ray and gamma-ray attenuation by optical glasses

Based on data concerning the density of glasses, the mass fractions of the chemical elements that enter into the composition of the glasses, and their mass attenuation coefficients of photonic radiation with a quantum energy from 20 keV to 3 MeV, the linear x-ray and gamma-ray attenuation coefficients of typical optical and radiation-resistant glasses are calculated. The chemical elements in the composition of the glasses are indicated that have the maximum effect on the linear attenuation coefficient of photonic radiation by glasses of the crown and flint groups. The thicknesses of the layers of these glasses are determined that attenuate the γ radiation of the radionuclides Co60 (1.25 MeV) and Cs137 (0.661 MeV) to one-half and one-tenth.

Viewing window with a high degree of protection from gamma and neutron radiation and the possibility of varying the parameters of the observation device

The inspection window of observation devices that are used when working with high-intensity gamma and neutron radiation or under extreme conditions, including when the consequences of accidents at atomic power plants are being cleaned up, must provide the necessary level of protection of the operators and the greatest observation angle of the site. The relationships that have been developed for the thicknesses of special optical materials make it possible to achieve an attenuation factor of gamma radiation of up to 5000 when the dose rate is as much as 5×106??R/h. The use of optical components with raster-conical structures creates the possibility of expanding the angular fields and of varying the direction of the viewing axes without changing the dimensional and composition parameters.

How the melting conditions affect the valence equilibrium of copper ions in aluminopotassium barium phosphate glass

This paper discusses copper-activated aluminopotassium barium phosphate glasses similar in composition to the matrix of KGSS 0180/35 phosphate laser glass, used to fabricate large-scale disk-shaped active elements of powerful laser systems with high output energy. The glasses were melted at various temperatures under neutral or oxidizing conditions. The quantitative Cu+/Cu2+ ratio and the contribution of the Cu2+ ions to the index of inactive absorption of the glass at the lasing wavelength (1.053  µm) was studied as a function of its melting conditions. The studies used absorption, luminescence, mass-spectrometric, and x-ray photoelectron analysis. It is established that the quantitative Cu+/Cu2+ ratio in the test glasses is mainly determined by the melting temperature at the homogenization stage of the glass.