Research On Glass Forming Ability Of R₂O?RO?-Ta₂O₅-SiO₂ Ternary System And Luminescence From Doped-bismuth

Bismuth doped laser glass is the research focus in the field of glass.It can be applied to the novel optical fiber amplifiers in the optical communication system because its broadband near-infrared?NIR?luminescence can cover the whole range of low-loss transmission of silica fiber.However,bismuth volatilization during host glass melting at a high temperature is an important issue.Hence,we conducted the research on the glass host of R₂O?RO?-Ta₂O₅-SiO₂showing lower melting temperature and enhancement of bismuth NIR luminescence.The key points can be summarized as follows:1.The glass forming region of R₂O?RO?-Ta₂O₅-SiO₂ ternary phase diagram is obtained.In the binary alkali silicate glass.the content of SiO₂ can only fluctuate from 60 mol%to 80mol%.However,in the ternary system,Li₂O/Na₂O-Ta₂O₅-SiO₂ has an expanded glass forming region covering the range of 0-40 mol%Ta₂O₅,20-40 mol%Li₂O/Na₂O and 40-80 mol%SiO₂,and BaO-Ta₂O₅-SiO₂ has an glass forming region covering 0-10mol%Ta₂O₅,30-50 mol%BaO and 50-70 mol%SiO₂.Ta₂O₅ replaces SiO₂ and depolymerize the glass network,which results in the increasing of density values and refractive indices,as well as the decreasing of the melting temperature.Such fundamental research will benefit the design and preparation of new functional glass.2.Normally,bismuth doped R₂O?RO?-Ta₂O₅-SiO₂ glass shows broadband near-infrared emission covering 1000-1600 nm excited by 400-500 nm Xe flash or 808 nm LD,and the peak position centered at 1200-1300 nm can be adjusted by changing the exciting wavelength.The lifetime of emission is 200-300?s.At the same time,anti-thermal degradation of luminescence can be realized in glass composition of 20Na₂O-12Ta₂O₅-67SiO₂-1Bi₂O₃,indicating their potential application.3.The mechanism of bismuth NIR emission influenced by glass composition and structure in R₂O?RO?-Ta₂O₅-SiO₂ glass systems.The glass modifiers R₂O or RO break the bridging oxygen in the glass network,which do harms to the stabilization of bismuth emission centers.However,with increasing them at a small scale?for example,15-20 mol%Na₂O?the bismuth emission can be strengthened because of lowered glass viscosity and improved bismuth homogeneity.Moderate Ta₂O₅ content?higher than 10 mol%with alkali oxide and lower than10 mol%with alkali earth oxide?can modulate the coordination of alkali ions and change the surrounding of bismuth,which helps to enhance the NIR emission.The results above can enrich the research on the origin of bismuth luminescence and contribute to the design of composition and the tuning of luminescence in bismuth doped laser glass and fiber.