掺铒碲钨酸盐玻璃及其平面波导

研制了一种用于宽带波导放大器的掺铒碲钨酸盐激光玻璃材料，对玻璃热稳定性、光谱性质进行了表征，并在其上采用离子交换法制作了平面光波导．掺铒碲钨酸盐玻璃的转变温度Tg和析品开始温度Tx分别为377．1和488．5℃；荧光半高宽为52nm；应用McCumber理论，计算得出Er^3+离子4I13／2→^4I15／2跃迁在峰值波长1532nm的受激发射截面为0．91×10^-20cm^2．不同条件下制作了在632．8nm处多模的平面光波导，通过拟合得到Ag^+离子在300℃的有效扩散系数De为2．82×10^-1

Effects of Yb3+ in Er3+/Yb3+ codoped fluorophosphate glasses

For the Er3+/Yb3+ codoped fluorophosphate glasses, Judd-Ofelt theory is used to analyse the influence of YbF3 as not a sensitizer but an average component on the spectroscopic properties around 1530 nm emission. The double roles of Yb3+, as a sensitizer and as an average component, are discussed. It is found that Yb3+ as an average component contributes to the increase of fluorescence lifetime, and Yb3+ as a sensitizer has the best sensitization when its concentration is 2.4 mol%.

Judd-Ofelt intensity parameters of Er3+ doped mixed alkali aluminophosphate glasses

Lithium sodium mixed alkali aluminophosphate glasses of the composition xNa(2)O-(15-x)Li2O-4B(2)O(3)-11Al(2)O(3)-5BaO-65P(2)O(5) (where x=0, 3.75, 7.5, 11.25 and 15 mol%) containing 0.5 mol% Er2O3 were prepared by melt quenching. The absorption spectra of Er3+ were studied from the experimental oscillator strengths and the Judd-Ofelt intensity parameters were obtained. The variations of Judd-Ofelt intensity parameters (Omega(2), Omega(4) and Omega(6)), experimental oscillator strengths of certain excited states of Er3+ and hypersensitive band positions with different mixed alkali content have been discussed in detail. It was found that there were similar effects of mixed alkali on both Judd-Ofelt intensity parameter 02 and the experimental oscillator strength of the hypersensitive transition, I-4(15/2) -> H-2(11/2). No shifts in the peak wavelength of the studied transitions were found in different glasses. (c) 2006 Elsevier B.V. All rights reserved.

Spectroscopic properties of fluorophosphate glass with high Er(3+)supercript stop concentration

Fluorophosphate glass with 4 mol.% ErF3 content was prepared. The different scanning calorimetry was conducted. Raman spectrum, infrared transmission spectrum, absorption spectrum were measured. Fluorescence spectrum and lifetime of emission around 1.53 mu m were measured under 970 nm laser diode excitation. The metaphosphate content in the composition is limited, but the maximum phonon energy of glass amounts to 1290 cm- 1, and is comparatively high. The full width at half maximum is about 56 nm, and is wider than for most of the materials investigated. The measured lifetime of I-4(13/2) -> I-4(15/2) transition, contributed by the high phonon energy, inefficient interaction of Er3+ ions, and low water content, amounts to no less than 7.36 ms though the Er3+ concentration is high. This work might provide useful information for the development of compact optical devices.

Upconversion emissions in Yb3+-Tm3+-doped tellurite glasses excited at 976 nm

Intense Tm3+ blue upconversion emission has been observed in Tm3+-Yb3+ codoped oxyfluoride tellurite glass under excitation with a diode laser at 976 nm. Three emission bands centered at 475, 650 and 796 nm corresponding to the transitions (1)G(4) -> H-3(6), (1)G(4) -> H-3(4) and F-3(4) -> H-3(6), respectively, simultaneously occur. The dependence of upconversion intensities on Tm3+ ions concentration and excitation power are investigated. For fixed Yb2O3 concentrations of 5.0 mol%, the maximum upconversion intensity was obtained with Tm2O3 concentration of about 0.1 mol%. The blue upconversion luminescence lifetimes of the Tm3+ transitions (1)G(4) -> H-3(6) are measured. The results are evaluated by the possible upconversion mechanisms.

Formation, thermal, optical and physical properties of GeS2-Ga2S3-AgCl novel chalcohalide glasses

Novel GeS2-Ga2S3-AgCl chalcohalide glasses had been prepared by melt-quenching technique, and the glass-forming region was determined by XRD, which indicated that the maximum of dissolvable AgCl was up to 65 mol%. Thermal and optical properties of the glasses were studied by differential scanning calorimetry (DSC) and Visible-IR transmission, which showed that most of GeS2-Ga2S3-AgCl glasses had strong glass-forming ability and broad region of transmission (about 0.45-12.5 mu m). With the addition of AgCl, the glass transition temperature, Tg decreases distinctly, and the short-wavelength cut-off edge (lambda(vis)) of the glasses also shifts to the long wavelength gradually. However, the glass-forming ability of the glass has a complicated evolutional trend depended on the compositional change. In addition, the values of the Vickers microhardness, H (v) , which decrease with the addition of AgCl, are high enough for the practical applications. These excellent properties of GeS2-Ga2S3-AgCl glasses make them potentially applied in the optoelectronic field, such as all-optical switch, etc.

Stability against crystallization and spectroscopic properties of Tm3+ doped fluorophosphate glasses

Fluorophosphate glasses with various content of Al(PO3)(3) were prepared. With the increment of Al(PO3)(3) content, density decreases while refractive index increases, and transition temperature, crystallization peak temperature and melt temperature increase which were suggested by differential scanning calorimetry. These glasses exhibit the best stability against crystallization with 7-9 mol'Yo Al(PO3)(3) content. Normalized Raman spectra were used to analyze structure and phonon state. The increment of Al(PO3)(3) content does not affect phonon energy but results in the augment of phonon density. Absorption spectra were measured. H-3(6) -> F-3(4) transition exhibits absorption at L band of the third communication window. Compared with the energy of Tm3+ excited states in other glass system, F-3(4) energy of Tm3+ in these glasses is considerable higher and H-3(4) energy is considerable lower, and it can be predicted that emission band of H-3(4) -> F-3(4) transition is close to the amplified band of gain-shift Tm3+ doped fiber amplifier. Analyses of Judd-Ofelt theory suggest when Al(PO3)(3) content is no more than 7 mol%, Judd-Ofelt parameters Omega(t) and the lifetime of H-3(4) energy level of TM3+ vary little with the increment of Al(PO3)(3) content, and when Al(PO3)(3) content is more than 7 mol%, Omega(2) and Omega(6) increase and radiative lifetime of H-3(4) energy level of Tm3+ drops sharply with the increment of Al(PO3)(3) content. (c) 2006 Elsevier B.V. All rights reserved.

Effect of bismuth oxide on the thermal stability and Judd-Ofelt parameters of Er 3(+)/Yb3(+) co-doped aluminophosphate glasses

The Er3+/Yb3+ co-doped glasses with compositions of xBi(2)O(3)-(65-x)P2O5-4Yb(2)O(3)-11Al(2)O(3)-5BaO-15Na(2)O (where x = 0, 2.5, 5, 7.5 and 10 mol%) were prepared using the normal melt quench technique. The optical absorption spectra of the glasses were recorded in the wavelength range 300-1700 nm. The effect of Bi2O3 content on the thermal stability and absorption spectra of glasses was investigated. In addition, the Judd-Ofelt parameters and oscillator strengths were calculated by employing Judd-Ofelt theory. It was observed that the positions of the fundamental absorption edge and cut-off wavelength shifted towards red as the content of Bi2O3 increased. However, there were no red shifts found both in the peak wavelength and in the center of mass wavelength of all absorption bands with Bi2O3 content increasing. The results of Judd-Ofelt theory analysis showed that Judd-Ofelt parameters Omega(t), (t = 2, 4, 6) changed sharply when Bi2O3 concentration exceeded 5 mol%. The variation trends of experimental oscillator strength were similar with those of Judd-Ofelt parameters as function of Bi2O3 concentrations. Moreover, differential scanning calorimetry experiments showed that the increases of Bi2O3 content weakened the network structure and then lowered the thermal stability of the glasses. The spontaneous emission probability A(rad), branching ratio beta and the radiative lifetime tau(rad) were also calculated and analyzed. The stimulated emission cross-section of Er3+ was calculated according to the McCumber theory. It was found that the stimulated emission cross-section of Er3+ was monotonically increases with Bi2O3 content increasing. (C) 2006 Elsevier B.V. All rights reserved.

SiO2 对Bi2O3-B2O3 玻璃体系光学、热学及结构的 影响

Glasses with compositions 50Bi2O3-xB2O3- (50-x)SiO2(x=0, 10, 20, 30, 40, 50) in mol% have been prepared by using a normal melt-quench technique. The effect of SiO2 addition on thermal stability, optical properties and structural characteristic on Bi2O3-B2O3 glass were systematically investigated by using XRD, DTA, ultraviolet-visible transmittance spectra, midinfrared transmittance spectra and Raman spectra. The experimental results demonstrate that, with the addition of SiO2, thermal stability of glass samples has been obviously improved. Once the amount of SiO2 is too much, the glass samples tend to be phase seperation which results in the decrease of thermal stability. With increasing SiO2 content, the UV cutoff edge firstly shifts to short-wave band and then shifts to long-wave band, and the transmittance of mid-infrared has been greatly improved. With substitution of SiO2 for B2O3, the [BO3] triangles and [BO4] tetrahedral groups are gradually replaced by [SiO4]. [BiO6] octahedral and [SiO4] tetrahedral units are connected forming a vibrational mode of Bi-O-Si. The physical chemistry and optical performance of Bi2O3-B2O3 glass were greatly improved by addition of SiO2.

Structural investigation on TeO2-BiCl3 glassy system

Glass systems of composition xBiCl(3)-(1-x)TeO2 (x=0.2, 0.4, 0.5 and 0.6, respectively) have been investigated by means of DSC, infrared absorption spectroscopy and Raman spectroscopy in order to obtain information about the transformation of structure, thermal and optical properties in the formation of the glass network. The results confirm that the addition of BiCl3 network former increases the glass forming ability and the optical transmission range. And also from Raman results a structural evolution was observed where the number of structural units described as [TeO3] trigonal pyramids, [TeO3+1] polyhedra and ionic behavior bonds (NBO) increases at the expense of the [TeO4] trigonal bipyramids. Bi3+ ions exist in network structure as [BiO6] or [BiCl6] octahedral coordination. As upconversion luminescence glass host, this glassy system is desired for optical properties but the thermal stability will still be improved. (c) 2005 Elsevier B.V. All rights reserved.

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.

Novel erbium-doped TeO2-based oxysulfide glasses: thermal and spectroscopic properties

Er3+-doped TeO2-based oxysulfide glasses have been prepared in argon atmosphere in carbon crucibles. The thermal analysis and spectroscopic properties of Er (3+) have been considered in terms of sulfide influence. As a function of composition, we have principally measured optical absorption, spontaneous emission and lifetime measurements. Judd-Ofelt theory was introduced to calculate bandwidth and emission cross-section. The results show the product FVMM x sigma(c) increase from 476.8 8 to 635.04 10(-21) cm(2) nm evidently with the addition of 10 mol% PbS into tellurite glass, which indicates a perfect effect on spectra property of Er3+ ions. (C) 2004 Elsevier B.V. All rights reserved.

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.

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.

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.