YELLOW BLUE LUMINESCENCES OF DY3+-DOPED BORATE GLASSES AND THEIR ANOMALOUS TEMPERATURE-VARIATIONS/

Compositional and temperature dependences of optical and fluorescence properties of Dy3+-doped berate glasses were investigated in the compo sition (95 - x)B2O3-xNa(2)O-5CaO. Among three Judd-Ofelt parameters th e Ohm(2) increased and the Ohm(6) decreased with increasing Na2O conte nt. Owing to the dependence of the Ohm(t) parameters, the branching ra tio of blue/yellow emissions from the F-4(9/2) level changed largely w ith compositions. The total spontaneous emission probability from the F-4(9/2) level increased and its lifetime decreased with Na2O content. In addition, with increasing temperature the lifetime of the F-4(9/2) level increased and the branching ratio also changed. These optical p roperties and their anomalous temperature variations are discussed com bined with the change of radiative decay rate of Dy3+ ions in the bera te glasses. (C) 1998 Elsevier Science B.V. All rights reserved.