Effect of TeO₂ on optical and 1.06 µm emission in Nd³⁺-doped phosphate glass for high-power lasers

In this work, we deal with glass composition, 29P 2 O 5 +(60− x )ZnO+10Na 2 O+xTeO 2 ( x =5−40mol.%) doped with 1 mol.% of Nd 2 O 3 . The samples are characterized by x ray diffraction, micro-Raman, optical absorption, and photoluminescence techniques. Refractive index ( n ) linearly increased with TeO 2 content, as well as the optical basicity (Λ) due to the strengthening of the covalent bond between cation and oxide ions. Such information was corroborated by Raman spectra via an increase of non-bridging oxygens. The maximum phonon energy is approximately 1010cm −1 , which is lower than reported for P 2 O 5 −ZnO−Na 2 O phosphate glass (1164cm −1 ). Detailed spectroscopic and luminescent properties based on TeO 2 content are discussed. From luminescence spectra, laser parameters were estimated, viz., radiative transition probabilities, radiative lifetimes, branching ratios, and emission cross sections. The results show that the optimal laser emission parameters are obtained for TeO 2 content equal to 20 mol.%, which evinces this glass composition as a promising host material for 1.06 µm high-power laser applications.