Optical Absorption and Fluorescence Properties of Er3+/Yb3+ Codoped Lead Bismuth Alumina Borate Glasses

Lead bismuth alumina borate glasses codoped with Er3+/Yb3+ were prepared by melt quenching technique. Optical absorption, FTIR and photoluminescence spectra of these glasses have been studied. Judd-Ofelt theory has been applied to to the f <-> f transitions for evaluating Omega(2), Omega(4) and Omega(6) parameters. Radiative properties like branching ratio beta(r) and the radiative life time tau(R) have been determined on the basis of Judd- Ofelt theory. Upconversion emissions have been observed under 980nm laser excitation at room temperature. Green and red up- conversion emissions are centered at 530, 550 and 656 nm corresponding to H-2(11/2) -> I-4(15/2), S-4(3/2) -> I-4(15/2) and F-4(9/2) -> I-4(15/2) transitions of Er3+ respectively. The results obtained are discussed quantitatively based on the energy transfer between Yb3+ and Er3+.