Effect of Yb(3+) on the Structural and Visible to Near-Infrared Wavelength Photoluminescence Properties in Sm(3+)-Yb(3+)-Codoped Barium Fluorotellurite Glasses

We report on the Sm(3+) and Sm(3+):Yb(3+)-doped barium fluorotellurite glasses prepared using the conventional melting and quenching method. The spectroscopic characterisations were investigated with Raman and FTIR to evaluate the glasses’ structural and hydroxyl (-OH) content. The Raman analysis revealed a structural modification in the glass network upon adding and increasing the Yb(3+) concentration from a TeO(3) trigonal pyramid to a TeO(4) trigonal bi-pyramid polyhedral. At the same time, the FTIR measurements showed the existence of -OH groups in the glass. Thus, under the current experimental conditions and nominal composition, the -OH group contents are too large to enable an effective removal. The near-infrared region of the absorption spectra is employed to determine the nephelauxetic ratio and bonding parameters. The average nephelauxetic ratio decreases, and the bonding parameter increases with the increasing Yb(3+) content in the glasses. A room temperature visible and near-infrared photoluminescence ranging from 500 to 1500 nm in wavelength and decay properties were investigated for glasses doped with Sm(3+) and Sm(3+)-Yb(3+) by exciting them with 450 and 980 nm laser sources. Exciting the Sm(3+)- and Sm(3+)-Yb(3+)-doped glasses by 450 nm excitation reveals a new series of photoluminescence emissions at 1200, 1293, and 1418 nm, corresponding to the (6)F(11/2) state to the (6)H(J) (J = 7/2, 9/2, 11/2) transitions. Under the 976 nm laser excitation, a broad photoluminescence emission from 980 to 1200 nm was detected. A decay lifetime decreased from ~244 to ~43 μs by increasing the Yb(3+) content, ascribing to concentration quenching and the OH content.