Spectroscopic properties of Er3+/Yb3+ co-doped fluorophosphate glasses for optical device applications

A series of Er3+/Yb3+ co-doped fluorophosphate glasses with varying YbF3 concentration were prepared by a high temperature melt quenching technique. The effect of sensitization on various spectroscopic properties of Er3+-doped fluorophosphate glasses was investigated. Using the Judd-Ofelt theory, the intensity parameters (Ωλ, λ = 2, 4 and 6) were evaluated from the absorption spectra of glasses. Absorption and emission cross-sections were determined by using the McCumber theory. The dependence of Er3+ ions near infrared emission (1.54 μm) on the Yb3+ concentration was investigated. The upconversion studies were also carried out at room temperature and low temperatures. The wider bandwidth (78 nm), larger emission cross-section (9.86 x 10-21 cm2) and longer fluorescence lifetime (12.37 ms) were noticed for the 4I13/2 → 4I15/2 transition of ABS3Er4Yb glass. The temperature sensing behavior of the ABS3Er5Yb glass was studied by using the fluorescence intensity ratio technique in the temperature range from 100 K to 280 K. The sensitivity and temperature of the maximum sensitivity were found to be of the order of 15 x 10−4 K−1 and 271 K, respectively. The results suggested that the present glass composition has possibilities for optical applications.