Optical absorption and fluorescence properties of Er3+ ion in MO-WO3-P2O5 glasses

Tungsten phosphate glasses mixed with the three different modifier oxides, viz. PbO, ZnO and CaO doped with Er2O3 were prepared. The glasses were characterised by X-ray diffraction spectra, electron microscopy and differential thermal analysis. Optical absorption and photoluminescence spectra of these glasses have been studied. From the measured intensities of various absorption bands of these glasses the Judd-Ofelt parameters Omega(2), Omega(4) and Omega(6) have been evaluated and compared with those of other reported glass systems. The Judd-Ofelt theory could be successfully applied to characterise the absorption and luminescence spectra of these glasses. From this theory various radiative properties like transition probability A, branching ratio beta(r), the radiative life time tau(R), and the emission cross-section sigma(E) for various emission levels of these glasses have been determined and reported. An attempt has also been made to throw some light on the relationship between the structural modifications and luminescence efficiencies of all the three glasses with the aid of ESR spectra. (C) 2003 Published by Elsevier Science Ltd.