Optical absorption and photoluminescence properties of Nd3+ doped mixed alkali phosphate glasses-spectroscopic investigations

摘要

Spectroscopic investigations were performed on 68NH(4)H(2)PO(4)center dot xLi(2)CO(3)(30 - x)K2CO3 and 68NH(4)H(2)PO(4)center dot xNa(2)CO(3)(30 - x)K2CO3 (where x=5, 10, 15, 20 and 25) glasses containing 2mol% Nd2O3. Various spectroscopic parameters (Racah (E-1, E-2, E-3), spin-orbit (xi(4f)) and configuration interaction (alpha)) are reported. Judd-Ofelt intensity parameters (Omega(2), Omega(4), Omega(6)) are calculated for Nd3+ doped two mixed alkali phosphate glass matrices. From the magnitude of Judd-Ofelt parameters, covalency is studied as a function of x in the glass matrix. Using Judd-Ofelt intensity parameters, total radiative transition probabilities (A(T)), radiative lifetimes (tau(R)), branching ratios (beta) and integrated absorption cross sections (Sigma) have been computed for certain excited states of Nd3+ in these mixed alkali phosphate glasses. Emission cross sections (sigma(p)) are calculated for the two transitions, (4)G(7/2) -> I-4(11/2) and (4)G(7/2) -> I-4(13/2) of Nd3+ in these mixed alkali phosphate glasses. Optical band gaps (E-opt) for direct and indirect transitions are reported. (C) 2008 Elsevier B.V. All rights reserved.