Preparation And Luminescent Properties On Er-Yb Co-doped BaO-TiO₂-SiO₂-Al₂O₃ Glass

Rare earth doped glass materials have a wide range of applications in lasers,optical communications,optical displays and so on.Recent studies have shown that erbium-doped titanate glass can promote the luminescence of Er³⁺,showing the application potential of broadband amplification in the near infrared band,and having a strong fluorescence output in the visible range.But it is difficult to prepare titanate glass by traditional methods,and the glass is difficult to be drawn into optical fiber.Therefore,after introducing the traditional glass forming body（SiO₂）into the titanate glass,The paper used high-temperature melt quenching to prepare barium titanosilicate（BaO-TiO₂-SiO₂-Al₂O₃,BTSA）glass,and studied the physics of BTSA glass,the influence of composition changes on the luminescence of Er³⁺and the luminescence characteristics of Er doped and Er-Yb co-doped BTSA glasses.In terms of the physical properties of BTSA glass,X-ray diffraction technology,thermal analysis technology,Raman spectroscopy and densitometer were used to analyze the state,thermal properties,microstructure and density of the sample.The results show that the transparent part of the sample is amorphous glass,and they have good thermal properties,and the glass transition temperature is above 700℃.The microstructure is mainly based on the Si-O-Ti network structure,and the maximum phonon energy of the glass is～940cm^-1.In the samples studied,the density of the glass is greater than 3.6g/cm³.Based on the absorption spectra of BTSA glass with different Ba/Ti,Judd-Ofelt theory and Mc Cumber theory were used to analyze the material’s strength parameterΩ_t（t=2,4,6）and emission cross section.The luminescence spectrum and fluorescence life curve of erbium-doped glass with different components were texted.The results show that the up-conversion luminescence of Er³⁺is very weak,and the maximum stimulated emission cross-section is 7.6×10^-21cm².As the content of TiO₂ decreases,the covalentity of BTSA glass increases,and the near-infrared fluorescence half-width（FWHM）becomes narrower,and the fluorescence lifetime increases.The maximum FWHM is 57 nm.Under the fixed glass composition,different concentration of Er doped and Er-Yb co-doped BTSA glass were prepared and their luminescence spectrum and fluorescence life curve were tested.The results show that,with the increase of Er³⁺,the near-infrared luminescence is enhanced,and the FWHM increases first and then decreases and then increases.When the concentration of Er³⁺is 1 mol%,the maximum FWHM is 65nm,and the fluorescence lifetime of Er³⁺is 3.711ms at this concentration.Thanks to the large absorption cross section of Yb³⁺at 980nm wavelength and the energy transfer between Er³⁺and Yb³⁺ions,the up-conversion luminescence of Er³⁺is greatly enhanced,and the intensity of green light is increased by 17 times,and the near-infrared FWHM and fluorescence lifetime of erbium ions are also promoted.Therefore,Er-Yb co-doped BTSA glass is promising to be used as the matrix material of fiber amplifiers to achieve broadband amplification.