Spectroscopic properties of Dy3+ ions in lithium borate and lithium fluoroborate glasses

Spectral study of Dy3+-doped borate glasses modified with lithium oxide and fluoride are presented. These glasses include lithium borates: (99 - x)Li2CO3 + xH(3)BO(3) + 1Dy(2)O(3),x = 39.5, 49.5, 59.5 and 69.5 and lithium fluoroborates: xLi(2)CO(3) + (49.5 - I)LiF + 49.5H(3)BO(3) + 1Dy(2)O(3),x = 24.75 and 0. Using Judd-Ofelt (JO) theory, the intensity parameters (Omega(lambda), lambda = 2, 4, 6) have been evaluated for all the six glasses. These intensity parameters are used to predict radiative properties that include electric (S-ed) and magnetic (S-md) dipole line strengths, radiative (A) and total radiative (A(T)) transition probabilities, lifetimes (tau(R)), branching ratios (beta(R)) for the excited (K-4(1)(13/2), F-4(3)(5/2), P-4(2)(3/2), M-4(21/2), (4)G(4)(11/2), I-4(3)(15/2), F-4(3)(9/2), F-6(9/2) and H-6(9/2)) levels of these Dy3+-doped lithium borate and lithium fluoroborate glasses along with 11 different systems doped with Dy3+ ions. The predicted values of tau(R) and beta(R) are compared with the experimental values for F-4(3)(9/2) transition. The stimulated emission cross-sections are also evaluated for F-4(3)(9/2) --> 77(6)H(J) (J = 7/2, 9/2, 11/2, 13/2 and 15/2) transitions. The dependence of the spectral characteristics of Dy3+ ions due to compositional changes of the glasses are examined. (C) 2000 Elsevier Science B.V. All rights reserved.