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A new method was used to prepare erbium-doped high silica (SiO2% > 96%) glasses by sintering nanoporous glasses. The concentration of erbium ions in high silica glasses can be considerably more than that in silica glasses prepared by using conventional methods. The fluorescence of 1532 nm has an FWHM (Full Wave at Half Maximum) of 50 nm, wider than 35 nm of EDSFA (erbium-doped silica fiber amplifer), and hence the glass possesses potential application in broadband fiber amplifiers. The Judd-Ofelt theoretical analysis reflects that the quantum efficiency of this erbium-doped glass is about 0.78, although the erbium concentration in this glass (6 x 103) is about twenty times higher than that in silica glass. These excellent characteristics of Er-doped high silica glass will be conducive to its usage in optical amplifiers and microchip lasers.

Compounds of Sr 3 Al 2 O 6 : Eu, Sr 4 Al 14 O 25 : Eu, and BaZnSiO 4 : Eu were synthesized by high-temperature solid state reactions. The doping Eu 3+ ions were partially reduced to Eu 2+ in Sr 4 Al 14 O 25 : Eu and BaZnSiO 4 : Eu prepared in an oxidizing atmosphere, N 2 + O 2 . However, such an abnormal reduction process could not be performed in Sr 3 Al 2 O 6 : Eu, which was also prepared in an atmosphere of N 2 + O 2 . Moreover, even though Sr 3 Al 2 O 6 : Eu was synthesized in a reducing condition CO, only part of the Eu 3+ ions was reduced to Eu 2+ . The existence of trivalent and divalent europium ions was confirmed by photoluminescent spectra. The different valence-change behaviors of europium ions in the hosts were attributed to the difference in host crystal structures. The higher the crystal structure stiffness, the easier the reduction process from Eu 3+ to Eu 2+ .

A method to fabricate europium ions doped-high silica glass for transparent fluorescence materials based on the fabrication and sintering technique of nano-porous silica glass was reported. Glasses impregnated with Eu ions and sintered at above 1150 °C in a reduction atmosphere show a very strong blue light from an emission band at about 430 nm due to the 4f65d→4f7(8S7/2) transition of the Eu2+ ions. On the other hand, the Eu-doped glass obtained by co-impregnated with Y3+ and V5+ ions and sintering in oxidation atmosphere behaves a very strong red emission band at about 615 nm with a UV excitation. An appearance of vanadate band in the excitation spectrum of Eu3+, Y3+ and V5+ ions co-doped high silica glass implies an effective energy transferring from VO43- to Eu3+ and effective excitation of Eu3+ by about 500 nm strong broad emission of VO43-.

We investigate the broadband infrared emission of bismuth doped and bismuth/dysprosium codoped chalcohalide glasses. It is found that the bismuth/dysprosium codoping can drastically enhance the fluorescence as compared with either bismuth or dysprosium doped glasses. Meanwhile, the full width at half maximum of bismuth/dysprosium codoped glasses is over 170 nm, which is the largest value among all the reported rare-earth doped chalcohalide glasses. An ideal way for energy consumption between bismuth and dysprosium ions is supposed. Such improved gain spectra of both bismuth and dysprosium ions may have potential applications in developing broadband fibre amplifiers.

The fabrication of one kind of large core area Nd 3+ doped silicate glass photonic crystal fiber, and demonstration of the fiber's waveguidence properties were reported. This fiber owns a random air hole distribution in the cladding. The measured minimum loss of this kind of fiber is 10 dB· m −1 at 660 nm. These fibers can sustain only a single mode at least over wavelength ranging from 660 nm to 980 nm.

A compact nonporous high silica (SiO2 % > 96%) glass containing 3400 ppm Er3+ ions, which was about ten times higher than that in Er-doped silica fiber amplifier (EDSFA), was synthesized by sintering porous glass immersed into erbium nitrate solution. The 1532 nm fluorescence has a FWHM (Full Width at Half Maximum) of 45 nm wider than that of EDSFA and possesses the glass with potential application in broadband fiber amplifiers. The Judd-Ofelt theoretical analysis reflects that Er3+ ions are located in a higher covalent environment which are comparable to those of aluminosilicate glass. (c) 2005 Elsevier B.V. All rights reserved.

We report on the fabrication of two kinds of large core area Nd3+ doped silicate glass photonic crystal fibres, and demonstration of the fibre waveguiding properties. The measured minimum loss of one kind of fibres is 2.5 db/m at 660nm. The fibres sustain only a single mode at least over the wavelength range from 660nm to 980nm.

The luminescent properties of Eu2+ doped, Tb3+ doped and Tb3+/Eu2+ co-doped high silica glass were investigated. The emission and excitation spectra of such glass samples were measured and compared. The spectra of Tb3+/Eu2+ co-doped sample’s is no equaled the superposition of the two single-doped glass samples’. A possible mechanism was discussed to explain that.

Eu (1 wt%) doped 15SiO2-25B2O3-30Al2O3-30Gd2O3 oxide glasses are prepared by high-temperature melt-quenching method in air and reduced atmosphere, respectively. The properties of scintillation and photoluminescence of the two samples are compared. When the samples fabricated in reduced atmosphere are excited by the X-ray and 395 nm violet light, a 450–550 nm blue-green light beam from Eu2+ and a 615 nm red light beam from Eu3+ are obtained. The intensity ratios between Eu3+ and Eu2+ are obviously different under different excitation sources. The intensity ratio under the excitation of the 395 nm violet light is 0.02 while it increases to 1.37 under the X-ray excitation. By analyzing the phonon sideband spectra of the samples, it is found that the Eu3+ ions around the former of Si are completely reduced into Eu2+ ions, while only part of Eu3+ ions around the former of B and Al are reduced into Eu2+ ions. Further investigation about the scintillation mechanism indicates that the sensitization of Gd and the energy transfer of Eu2+→Eu3+ near the formers of B and Al increase the scintillation performances of Eu3+ ions in the reduced glass samples.

The Judd-Ofelt intensity parameter Ωt of a novel Er3+ doped high silica glass was calculated. The large values of Ω2,6 (Ω2=8.15×10-20,Ω6=1.22×10-20) indicate that the local structure of Er3+ has higher asymmetry and lower covalency than other oxide glasses. McCumber theory was used to calculate the stimulated emission cross section of 4I13/2→4I15/2 transition, the result was 0.51pm2. Despite the Er3+-doped concentration in high silica glass being about ten times greater than that in silica fiber, its fluorescence lifetime and quantum efficiency were 6.0ms and 66.0%， respectively. This novel Er3+-doped glass can be used in optical amplification and microchip laser.