Effect of coloring impurities on the absorption in neodymium phosphate laser glass at a lasing wavelength

Abstract

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 Cu 2+ ions at a concentration higher than 0.5 ppm. At a lower copper concentrations, the total contribution of Fe 2+ , V 4+ , Ni 2+ , and Co 2+ impurity ions to the nonactive absorption coefficient is comparable to that of Cu 2+ 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

“…In the glasses melted on an industrial scale, the concentrations of all coloring impurities and, correspondingly, their contributions to the inactive absorption coefficient were comparable to each other. In order to determine the contributions of the coloring impurities to the inactive absorption coefficient of glass C , their concentrations in this glass were measured by the mass spectroscopic technique described in [4]. The error in the determination of the element concentrations with this technique was equal to 10%.…”

“…In this respect, the inactive absorption coefficients of the samples of glasses C were measured on an FM 94-M spectrophotometer with an error of ±0.0001 cm -1 [4].…”

“…The composition and technology for manufacturing the domestic neodymium glass KGSS 0180 used in these amplifiers is described in [1]. It is known that the inactive absorption coefficient of neodymium glasses depends substantially on the presence of coloring impurities [3,4], among which iron occupies a special place. Compared to other impurities, the concentration of iron (5-20 ppm) in the glass under consideration considerably exceeds the concentrations of other coloring impurities (10 -1 -10 -2 ppm).…”

“…Compared to other impurities, the concentration of iron (5-20 ppm) in the glass under consideration considerably exceeds the concentrations of other coloring impurities (10 -1 -10 -2 ppm). Moreover, iron contained in the phosphate glass in an oxidation state of +2 (Fe 2+ ) absorbs optical radiation in the near-IR spectral range (the maxima of the absorption bands associated with the Fe 2+ ions are located at 1.055 and 2.300 µ m [3][4][5][6]) and, hence, substantially affects the inactive absorption coefficient of the glass. Iron can enter into the glass composition in the form of Fe 2+ ions and Fe 3+ ions, which virtually do not absorb light with a wavelength of 1.053 µ m, because the maxima of their absorption bands for phosphate glasses occur at 0.2, 0.4, 0.5, and 0.7 µ m [3,6].…”

Investigations on the photoluminescence spectra and its defect-related nature for the ultraviolet transmitting fluoride-containing phosphate-based glasses

“…With the increasing demands of high-performance UV transmitting materials to be applied for lens system in UV microlithography equipments, excimer laser systems and other special UV optics, from several decades ago till nowadays, the investigations [5][6][7][8][9][10][11][12][13][14] on the optical performance, detailed structure-property relations of various fluoride-phosphate and other phosphate-based glasses have never stopped in the pursuit of developing new types of fluoride-containing phosphate-based glasses. The effects of intrinsic defects, extrinsic impurity ions, the irradiations of UV-lamp, excimer lasers, X-ray and Gamma-ray, etc., have been widely studied in order to explore the related defect formation mechanism and the applicability of these phosphate-based glass materials.…”