R. Maâlej

Spectroscopic analysis of trivalent Nd 3+ /Yb 3+ ions codoped in PZS host glasses as a new laser material at 1.06 μm

Abstract This paper reports on the spectral results of Nd3+/Yb3+ ions codoped 50P2O5-30ZnO-20SrO (PZS, in mol.%) glasses which were prepared by a melting technique. The glass transition temperature and spectroscopic properties of these glasses were estimated. From the absorption spectra, Judd-Ofelt (J-O) intensity parameters (Ωk), were calculated. Using J-O intensity parameters, several radiative properties such as spontaneous transition probabilities (AR), radiative branching ratios (βR) and radiative lifetimes (τR) were determined for the exciting levels of the Nd3+ ions. The large value of the stimulated integrated cross-section and the lifetimes of Nd3+ level revealed the potential of the present glasses as a candidate for generating laser emission at 1.06 μm as continuous wave laser action and exploited for optical device fabrication. A broad emission band from 950 to 1100 nm was detected when the Nd3+/Yb3+ was co-doped in PZS glasses excited by 805 nm lighting diode (LD). The energy transfer process from Nd3+→Yb3+ in co-doped phosphate glasses was described in this paper.

Structure Prediction of Rare Earth Doped BaO and MgO Containing Aluminosilicate Glasses–the Model Case of Gd2O3

The medium-range atomic structure of magnesium and barium aluminosilicate glasses doped with Gd2O3 as a model rare earth oxide is elucidated using molecular dynamics simulations. Our structure models rationalize the strong dependence of the luminescence properties of the glasses on their chemical composition. The simulation procedure used samples’ atomic configurations, the so-called inherent structures, characterizing configurations of the liquid state slightly above the glass transition temperature. This yields medium-range atomic structures of network former and modifier ions in good agreement with structure predictions using standard simulated annealing procedures. However, the generation of a large set of inherent structures allows a statistical sampling of the medium-range order of Gd3+ ions with less computational effort compared to the simulated annealing approach. It is found that the number of Si-bound non-bridging oxygen in the vicinity of Gd3+ considerably increases with growing ionic radius and concentration of network-modifier ions. In addition, structure predictions indicate a low driving force for clustering of Gd3+, yet no precise correlation between the atomic structure and luminescence lifetimes can be conclusively established. However, the structure models provided in this study can serve as a starting point for future quantum mechanical simulations to shed a light on the relation between the atomic structure and optical properties of rare earth doped aluminosilicate glasses.