Evaluation of TeO2 content on the optical and spectroscopic properties of Yb3 +-doped calcium borotellurite glasses.

This paper reports the synthesis and the characterization of Yb 3 + -doped calcium borotellurite (CaBTeX) glasses with composition 10CaF 2 –(29.5 − 0.4x)CaO–(60 − 0.6x)B 2 O 3 –xTeO 2 –0.5Yb 2 O 3 (x = 10, 16, 22, 31 and 54 mol%). The results of XRD confirm the amorphous character of all the samples. The density, molar volume, refractive index and electronic polarizability values show an increase with TeO 2 content. Otherwise, the optical band gap energy shows a decrease with the increase of TeO 2 content. The replacement of CaO and B 2 O 3 by TeO 2 changes the glass structure, which decreases the excited Yb 3 + /cm 3 and, consequently, the luminescence intensity. The temperature dependence of luminescence was studied for all the samples up to 420 K. The fluorescence lifetime does not change significantly due to TeO 2 addition. In addition, absorption and emission cross section were calculated and present high values as compared to other tellurite and phosphate glasses. [ABSTRACT FROM AUTHOR]