Thermal analyses, spectral characterization and structural interpretation of Yb3+ doped TeO2-ZnO-ZnCl2 glasses

Bulk-lasses have been prepared in the TeO2-ZnO-ZnCl2 systems. Their characteristic temperatures were determined and analyzed. Raman and FT-IR spectra were used to analyze the effect of ZnCl2 on the structure and spectral properties of tellurite glasses and OH- groups in this glass system. The spectroscopic properties including absorption spectra, emission cross-sections and fluorescence lifetimes of Yb3+ in TeO2-ZnO-ZnCl2 were measured and calculated. It is demonstrated that the progressive replacement less than 20 mol% of TeO2 by ZnCl2 improves the thermal stability, removes the OH- groups, turns TeO4 bipyramidal arrangement into TeO3 (and/or TeO3+1) trigonal pyramids structures and results in the decrease of the symmetry of the structure, which increases the emission cross-sections and lifetimes. But when the content of ZnCl2 up to 30 mol%, the glass system becomes more hygroscopic and introduces more OH- groups, which decrease the emission cross-sections and shorten the lifetimes. The results show that the glass system with (TeO2)-Te-69-(ZnO)-Zn-10-20ZnCl(2)-1Yb(2)O(3) is a desirable component for active laser media for high power generation. (c) 2005 Elsevier B.V. All rights reserved.

Effect of F- ions on emission cross-section and fluorescence lifetime of Yb3+-doped tellurite glasses

The effects of F- ions in Yb3+-doped tellurite glass systems on the emission cross-section and measured fluorescence lifetime are investigated. The results show that both the emission cross-section and the fluorescence lifetime of Yb3+ ions increase from 1.32 to 1.39 pm(2) and from 0.93 to 1.12 ms respectively with the increase of F- ions from 0 to 10 mol% and that such oxyfluoride tellurite glass system is a promising laser host matrix for high power generation. FT-IR spectra were used to analyze the effect of F- ions on the structure of tellurite glasses and the change of OH- groups in this glass system. Analysis demonstrates that the addition of fluoride decreases the symmetry of the structure of tellurite glasses resulting in increasing of the emission cross-section and removes the OH- groups resulting in increasing of the measured fluorescence lifetime of Yb3+ ions. (c) 2005 Elsevier B.V. All rights reserved.

Effect of F- ions on physical and spectroscopic properties of Yb3+-doped TeO2-based glasses

The effects of F- ions on physical and spectroscopic properties of the Yb3+ in tellurite glass system are investigated. The results show that the glass system takes on good thermal stability with the content of ZnF2 lower than 15 mol%, both the emission cross-section and the fluorescence lifetime of Yb3+ ions increase evidently which indicate that such oxyfluoride tellurite glass system is a promising laser host matrix for high power generation. FT-IR spectra were used to analyze the effect of F- ions on the structure of tellurite glasses and OH- groups in this glass system. Analysis demonstrates that addition of fluoride decreases the symmetry of the structure of tellurite glasses which increases the emission cross-section and removes the OH- groups, and which improves the measured fluorescence lifetime of Yb3+ ions. (c) 2004 Elsevier B.V. All rights reserved.

Effect of F- ions on spectroscopic properties of Yb3+-doped zinc-tellurite glasses

this paper is retracted

Blue cooperative luminescence in Yb3+-doped tellurite glasses excited at 1.064 mu m

Blue luminescence emission around 480 nm through cooperative upconversion from pairs of Yb3+ ions implanted into 60TeO(2)-10GeO(2)-10K(2)O-10Li(2)O-10Nb(2)O(5) tellurite glasses and excited by a cw laser at 1.064 mum is demonstrated. Cooperative luminescence emission enhancement owing to the temperature dependent multiphonon-assisted anti-Stokes excitation process of the ytterbium ions is also observed. The experimental results revealed a fourfold enhancement in the cooperative luminescence emission when the sample was heated in the temperature range of 20 degreesC-260 degreesC. The thermally induced enhancement is assigned to the effective absorption cross-section for the ytterbium ions which is an increasing function of the medium temperature. (C) 2002 American Institute of Physics.

Spectroscopic properties of Yb3+ doped PbO-Bi2O3-Ga2O3 glasses for IR laser applications

PbO-Bi2O3-Ga2O3 glasses doped with different concentrations of Yb3+ are presented. The spectroscopic properties and laser parameters are calculated and a comparison between different results obtained when calculating the Yb3+ emission cross-section with the reciprocity method and with the Fuchtbauer-Ladenburg formula is presented. The behavior of the near-infrared luminescence is described theoretically by a rate equation and compared with the experimental results. This host doped with Yb3+ is a promising material for laser action at 1019 nm, with properties similar to other known glasses used as active laser media; the emission cross-section of 1.1 x 10(-20) cm(2), the high absorption cross-section (of 2.0 x 10(-20) cm(2)) and a minimum pump intensity of 2.4 kW/cm(2) are interesting properties for short pulse generation. (C) 2005 Elsevier B.V. All rights reserved.

Compositional influence on spectroscopic properties of Yb3+ doped tellurite glasses

Spectroscopic properties of ytterbium-doped tellurile glasses with different compositions are reported. Results of linear refractive index, absorption and emission spectra, and fluorescence lifetimes are presented. The studied samples present high refractive index (∼2.0) and large transmission window (380-6000nm). Absorption and emission cross-sections are calculated as well as the minimum pump laser intensity. The results are compared with the values of other laser materials, in order to investigate applications as laser media in the infrared region.

White light generation in Tm3+/Ho3+/Yb3+ doped PbO-GeO2 glasses excited at 980 nm

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Spectroscopic and structural properties of YbF3-doped fluorophosphate glasses

Compositional influences on the spectroscopic properties of Yb3+ and the structural variations with the introduction of YbF3 were studied in fluorophosphate glasses. Emission cross-section (sigma(emi)) and gain coefficient (sigma(emi) x tau(f)) were calculated which exhibit maximum at RF2 = 33 mol%. YbF3 has an important effect on the glass forming ability of fluorophosphate glasses when RF2 is over 36 mol%. The study of Raman spectra showed big differences on the glass structure between non-Yb3+ and Yb3+ -doped glasses. The main building units in Yb3+-doped samples are metaphosphate groups, pyrophosphate groups (P-2(O,F)(7), PO3F), Al[F-6] +Al[O,F](6) and F3Al-O-AlF3 while those of the non-Yb3+-doped glasses are monophosphate group P(O,F)(4), little pyrophosphate group, Al[F-4] + Al[F-6] + Al[O,F](4) + Al[O,F](6) and F3Al-O-AlF3, which means Yb3+ ions contribute to a better glass polymerization and network uniformity. (C) 2004 Elsevier B.V. All rights reserved.

Effects of PbF2 on the spectroscopic, lasing and structural properties of Yb3+-doped fluorophosphate glass

Effect of PbF2 on Yb3+ -doped fluorophosphate glasses is studied. Results indicate that proper amount of PbF2 has absolute advantages in improving the crystallization stability of fluorophosphate glasses. T, value performs a decreasing and increasing tendency with 25 mol% PbF2 as the turning-point. And the spectroscopic properties such as absorption and emission cross section, effective fluorescence linewidth are apparently enhanced with PbF2 over 25 mol%. Lasing parameters beta, I-sat and I-min increase slightly with the addition of PbF2. Raman analysis proves that over 20 mol% PbF2, destroys the phosphate vibration groups greatly. (c) 2005 Elsevier Ltd. All rights reserved.

Influence of TeO2, PbF2, ZnF2 on the spectroscopic and lasing properties of Yb3+ doped fluorophosphate glass

The influence of TeO2 on the crystallization stability, thermal stability, spectroscopic and lasing properties of Yb3+ doped fluorophosphate (FP) glass was studied. It is shown that 2 mol% TeO2 is the optimum doping amount which results in better spectroscopic and lasing properties as well as improve the crystallization and thermal stabilities of the glass. In order to enhance the physical and optical properties further, the effect of PbF2 and ZnF2 to the TeO2 contained FP glasses is also investigated, which shows that PbF2 has advantages in improving the crystallization properties while ZnF2 is preferable in enhancing spectroscopic and lasing properties. Results indicate that the co-existence of TeO2, PbF2 or ZnF2 is an effective way to enhance the spectroscopic, lasing and physical properties of Yb3+ doped FP glasses. (c) 2004 Published by Elsevier B.V.

Blue cooperative luminescence properties in Yb3+ doped GeO2-PbO-Bi2O3 vitreous system for the production of thin films

Germanate glasses are of interest for optoelectronic applications because they combine high mechanical strength, high chemical durability and temperature stability with a large transmission window (400 to 4500 nm) and high refractive index (2.0). GeO2-PbO-Bi2O3 glasses doped with Y-b(3+) were fabricated by melting powders in a crucible and then pouring them in a brass mold. Energy Dispersive Spectroscopy showed that the glass composition has a high spatial uniformity and that the Yb concentration in the solid sample is proportional to the Yb concentration in the melt, what was confirmed by absorption measurements. Intense blue emission at 507 nm was observed, corresponding to half of the wavelength of the near infrared region (NIR) emission; besides, a decay lifetime of 0.25 ms was measured and this corresponds to half of the decay lifetime in the infrared region; these are very strong indications of the presence of blue cooperative luminescence. Larger targets have been produced to be sputtered, resulting in thin films for three dimensional (3D) display and waveguide applications. (c) 2006 Elsevier B.V. All rights reserved.

Multicolor upconversion of Er3+/Tm3+/Yb3+ doped oxyfluoride glass ceramics

Er3+/Tm3+/Yb3+ tricloped oxyfluoride glass ceramics was synthesized in a general way. Under 980 nm LD pumping, intense red, green and blue upconversion was obtained. And with those primary colors, multicolor luminescence was observed in oxyfluoride glass ceramics with various dopant concentrations. The red and green upconversion is consistent with F-4(9/2) -> I-4(15/2) and H-2(11/2), S-4(3/2) -> I-4(15/2) transition of Er3+ respectively. While the blue upconversion originates from (1)G(4) -> H-3(6) transition of Tm3+. This is similar to that in Er3+/Yb3+ and/or Tm3+/Yb3+ codoped glass ceramics. However the upconversion of Tm3+ is enhanced by the energy transfer between Er3+ and Tm3+. (c) 2006 Published by Elsevier B.V.