Zhang Xianghua

Influence of B2O3 on Spectroscopic Properties of Er3+/Yb3+ Co-Doped Tungsten-Tellurite Glasses

Abstract A series of novel Er 3+ /Yb 3+ co-doped (85 – x)TeO 2 -15WO 3 - xB 2 O 3 (TWB; x = 2%, 5%, 8% (mole fraction)) glasses were prepared. Influence of B 2 O 3 on the spectroscopic properties of Er 3+ /Yb 3+ co-doped tungsten-tellurite glasses were investigated. It is found that the intensity of 1.5 μm fluorescence, lifetime of the 4 I 13/2 level and upconversion fluorescence all decrease with the increase of B 2 O 3 content. The product of full width at half maximum (FWHM) and stimulated emission cross-section (σ) of Er 3+ : 4 I 13/2 → 4 I 15/2 transition has an optimum when B 2 O 3 is 5% (mole fraction). The emission spectra of Er 3+ : 4 I 13/2 → 4 I 15/2 transition was analyzed using peak-fit routine, and an equivalent four-level system was proposed to estimate the stark splitting for the 4 I 15/2 and 4 I 13/2 levels of Er 3+ ions in TWB glasses at room temperature.

Upconversion Luminescence of Er3+ Ions in Transparent Germanate Glass Ceramics Containing CaF2 Nanocrystals

The visible upconversion and near-infrared luminescence of Er3+ ions in germanate glass ceramics containing CaF2 nanocrystals are investigated. The nanocrystals are characterized by x-ray diffraction (XRD) and transmission electron microscopy, showing their mean sizes less than 20 nm. High transmittance of the glass ceramics is displayed by absorption spectra. The upconversion luminescence intensity in the glass ceramics increases significantly with increasing temperature. Both the shifts of the XRD peaks and the Stark-split shown in the luminescence spectra indicate the entrance of the Er3+ ions into the CaF2 nanocrystals, which is confirmed by a Judd–Ofelt analysis. Possible mechanisms of the upconversion luminescence are analyzed.

Improved Fluorescence from Tm3+/Er3+/Ce3+ Triply Doped Bismuth-Silicate Glasses for S+C-bands Amplifiers

Fluorescence of Tm3+/Er3+ codoped bismuth-silica (BS) glasses and the sensitization of Ce3+ are investigated. It shows that Ce3+ codoping with Tm3+/Er3+ in BS glasses results in a quenching of Tm3+ ion emission from 3F4 to the 3H6 level. Consequently, the 1.47 μm emission occurs after the population inversion between the 3H4 and 3F4 levels. Furthermore, the codoped glasses show the broad emission spectra over the whole S and C bands with full-width at half-maximum (FWHM) up to about 119 nm, as it combines 1.55 μm emission band of Er3+ with 1.47 μm emission band of Tm3+ under 800 nm excitation.

Gadolinium-Induced Multi-Effect on Properties of IR Transmitting Chalcogenide Glasses

We introduce gadolinium in chalcogenide glasses to exert unexpectedly the multiple magical effects on both optical and thermal mechanical properties of chalcogenide glasses. Notable increases in transition temperature Tg and microhardness Hv were observed due to structural densification and microcrystallization. Calculated molar volume values, differential scanning calorimetry and x-ray diffraction measurements provide supporting evidence. Gadolinium also acts as an oxygen getter by removing or weakening oxygen-related absorption bands, which is associated with the higher negative electrode potential.

The Preparation and Photoluminescence Properties of Fluorosilicate Glass Ceramics Containing CeF3:Dy3+ Nanocrystals

Ce3+ and Dy3+ co-doped oxyfluoride glasses and glass ceramics containing CeF3 nanocrystals are prepared in a reducing atmosphere. XRD measurements and the calculated lattice parameters suggest that Dy3+ ions are incorporated with precipitated CeF3 nanocrystals along with a rise in the Dy3+ concentration or an increase in the annealing temperature. The glass ceramics emit white light close to the CIE coordinates of (0.3,0.3), derived from a combination of Ce3+ and Dy3+ emission. The CIE chromaticity coordinates of the Ce3+ and Dy3+ co-doped glass ceramics can be tuned by varying the ratio of Ce3+/Dy3+, while the luminescence intensity can be enhanced by heat treatment above 620°C.