362 resultados para Glass compositions
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采用改进的外束质子激发x射线荧光、电感耦合等离子体原子发射光谱分析等技术,对广西合浦地区出土的一批汉代古玻璃样品的化学成分和结构特性等进行了检测。结果表明:两汉时期,合浦地区的古代玻璃存在K2O—SiO2、PbO-BaO-SiO2、PbO—SiO2、Na2O-K2O-PbO-SiO2、(Na2O)K2O-CaO—SiO2等多种类型,但绝大多数为K2O—SiO2玻璃。表面风化可引起K2O-SiO2玻璃表面K2O等助熔剂的流失和富硅层的形成。综合化学成分以及器型特征,认为我国汉代K2O—SiO2玻璃制造技术可
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abstract {Proton induced X-ray emission (PIXE) technique is an effective method for the chemical composition analysis of ancient glass samples without destruction. Chemical composition of the ancient glass samples dated from the Warring States Period (770-476 B.C.) to the Six Dynasties Period (220-589 A.D.), which were unearthed in Sichuan area, was quantitatively determined by the PIXE technique. The results show that the glass Bi (disc) and the glass eye beads of the Warring States Period all belong to the PbO-BaO-SiO2 system. According to the composition and shape, we infer that these glass Bi and eye beads were made in China. Whereas, the chemical compositions of the glass ear pendants and beads of the Six Dynasties Period are varied, including K2O-CaO-SiO2, K2O-SiO2 and other glass systems. Based on the obtained results and those from literatures, some questions related to the technical propagation of the ancient Chinese glass are discussed.}
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Nd-doped phosphate glass belt lasers pumped by laser diodes are demonstrated. The Nd-glass belt with a large cross-section and a small Fresnel number is air-cooled to provide around 18-W continuous wave (CW) output power with a beam quality factor of My2
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The heat generation in a flashlamp-pumped Nd:glass disk amplifier is studied by the simulation of the whole pumping process, which is based on the ray-tracing method. The results of temperature rise distribution as well as gain distribution are presented. The evolution of heat generation in disk during the pumping process is discussed in detail. Some main factors related with the thermal effect, such as the quantum efficiency, fluorescence lifetime, and pulse duration, are investigated through studying the ratio of the heat generation to energy storage in the gain medium. The influence of each parameter on heat generation is studied carefully, and the results provide ways to decrease the heat generation during the pumping process. (c) 2005 Society of Photo-Optical Instrumentation Engineers.
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The optical loss coefficient at 1053-nm wavelength, influenced by Fe ions in N31-type Nd-doped phosphate laser glass, was determined precisely and analyzed in detail. It is found that the optical loss coefficient per unit of Fe concentration (cm^(-1)/ppmw) increases with Fe concentration in the range of 0---300 ppmw, but it approaches a constant as the Fe concentration is larger than 300 ppmw. Such a concentration effect is due to a shift in the redox equilibrium between Fe3+ and Fe2+ ions in the glass. The effect of oxygen pressure, temperature, and variable valence states of other metal ions in glass samples on the optical loss is also discussed.
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A novel Vb(3+)-Er-(3+) codoped phosphate glass for high power flashlamp pumping and high repetition rate laser at 1.54 mu m, designated EAT5-2, is developed. The weight-loss rate of is 1.3 x 10(-5) gcm(-2) h(-1) in boiling water, which is comparable to Kigre's QX-Er glass. Some spectroscopic parameters are analysed by Judd-Ofelt theory and McCumber theory The emission cross section is calculated to be 0.73 x 10(-20) cm(2). The thermo-mechanical properties of EAT5-2 are modified after an ion-exchange chemical strengthening process in a KNO3/NaNO3 molten salt bath. The thresholds for optical damage from the flashlamp pumping are tested on glass rods. A repetition rate of 15 Hz is achieved for chemically strengthened glass. The laser experimental results at. 1.54 mu m from flashlamp pumping are also reported.
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Er3+:Yb3+ codoped tellurite-fluorophosphate (TFP) glass ceramic exhibits much stronger upconversion luminescence. The intensity of the 540 nm green light and 651 nm red light of the TFP glass ceramic is 120 times and 44 times stronger than that of the fluorophospahte (FP) glass, respectively. XRD analysis shows that the nanocrystal in TFP glass ceramic is SrTe5O11. TFP glass ceramic also displays much higher upconversion fluorescence lifetime and crystallization stability. The narrow and strong peak at 540 nm is very ideal for practical upconversion luminescence realization. This work is a new trial for exploring non-PbF2 involved nanocrystal upconversion glass ceramics.
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In this study, we examined the microstructure of crystals generated in borate glass by femtosecond laser irradiation (FSLI). The distribution of the high-temperature and low-temperature phases of barium metaborate crystals produced in the borate glass is analyzed using Raman spectroscopy. We then propose the possible mechanism for the generation of crystals in glass by FSLI.
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This letter reports the ultrabroadband infrared luminescence from 1000- to 1700-nm wavelength range and demonstrate optical amplification at the second optical communication window in a novel bismuth-doped germanosilicate glass. The full-width at half-maximum of the luminescence is about 300 mn and the optical gain is larger than 1.37 within the wavelength region from 1272 to 1348 nm with pump power 0.97 W. This material could be useful to fabricate ultrabroadband optical fiber amplifiers.
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Dy3+ doped oxyfluoride silicate glass was prepared and its optical absorption, 1.3 mu m emission, and upconversion luminescence properties were studied. Furthermore, the Judd-Ofelt [Phys. Rev. 127, 750 (1962); J. Chem. Phys. 37, 511 (1962)] intensity parameters, oscillator strengths, spontaneous transition probability, fluorescence branching ratio and radiative lifetime were calculated by Judd-Ofelt theory, while stimulated emission cross section of H-6(9/2)+F-6(11/2)-> H-6(15/2) transition was calculated by McCumber theory [Phys. Rev. A. 134, 299 (1964)]. According to the obtained Judd-Ofelt intensity parameters Omega(2)=2.69x10(-20) cm(2), Omega(4)=1.64x10(-20) cm(2), and Omega(6)=1.64x10(-20) cm(2), the radiative lifetime was calculated to be 810 mu s for 1.3 mu m emission, whose full width at half maximum and sigma(e) were 115 nm and 2.21x10(-20)cm(2), respectively. In addition, near infrared to visible upconversion luminescence was observed and evaluated. The results suggest that Dy3+ doped oxyfluoride silicate glass can be used as potential host material for developing broadband optical amplifiers and laser applications.
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We report on the fabrication and characterization of low-loss planar and stripe waveguides in a Nd3+-doped glass by 6 MeV oxygen-ion implantation at a dose of 1x10(15) ions/cm(2). The dark mode spectroscopy of the planar waveguide was measured using a prism coupling arrangement. The refractive index profile of the planar waveguide was reconstructed from a code based on the reflectivity calculation method. The results indicate that a refractive index enhanced region as well as an optical barrier have been created after the ion beam processing. The near-field mode profiles of the stripe waveguide were obtained by an end-fire coupling arrangement, by which three quasitransverse electric modes were observed. After annealing, the propagation losses of the planar and stripe waveguides were reduced to be similar to 0.5 and similar to 1.8 dB/cm, respectively. (c) 2007 American Institute of Physics.
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Transparent Ni2+-doped MgO-Al2O3-TiO2-SiO2 glass ceramics were prepared, and the optical properties of Ni2+-doped glass ceramics were investigated. Broadband emission centered at 1320 nm was observed by 980 nm excitation. The longer wavelength luminescence compared with Ni2+-doped Li2O-Ga2O3-SiO2 glass ceramics is ascribed to the low crystal field hold by Ni2+ in MgO-Al2O3-TiO2-SiO2 glass ceramics. The change in optical signals at the telecommunication bands with or without 980 nm excitation was also measured when the seed beam passes through the bulk gain host.(C) 2007 American Institute of Physics.
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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.
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Er3+ doped multicomponent fluoride based glass was prepared. These precursor fluoride glass samples were then heated using different schedules. Crystalline phase particles were successfully precipitated in the multicomponent fluoride glass samples after heat treatment. The influence of heat treatment on the spectroscopic properties of Er3+ in multicomponent fluoride based glass samples were discussed. Small changes of the Judd-Ofelt parameters Omega(i) (i = 2,4,6) were found in multicomponent fluoride glass samples before and after heat treatment compared to oxyfluoride telluride glass. Preparation conditions used to produce transparent multicomponent fluoride glass ceramics doped with rare-earth ions are discussed. (c) 2007 Elsevier B.V. All rights reserved.