Optical spectroscopy of the Er-doped glasses with 3CaO-Ga2O3-3GeO2 composition

Optical absorption, emission and luminescence excitation spectra as well as the luminescence kinetics of the Er3+ ions (amount of Er-0.7 wt.%) in glasses with garnet Ca3Ga2Ge3O12 (or 3Ca0-Ga2O3-3GeO(2)) composition were investigated in the UV-visible spectral region. By optical spectroscopy it was shown that the erbium is incorporated into the glass network as Er3+ ions (4f(11) electron configuration, I-4(15/2) free ion ground state), exclusively. All observed transitions of the Er3+ ions in glasses with 3CaO-Ga2O3-3GeO(2) composition in the UV-visible spectral region were identified. Optical spectra of the Er3+ ions can be analysed in the framework of Judd-Ofelt theory. The Er3+ luminescence decay curve for S-4(3/2) -> I-4(15/2) transition (lambda(max) = 555 nm) obtained at room temperature was satisfactory described by two-exponential approximation with lifetimes tau(1) = 10.6 mu s and tau(2) = 22.4 mu s. The peculiarities of spectroscopic properties, luminescence kinetics and local structure of the Er3+ centres in the glasses with 3CaO-Ga2O3-3GeO(2) composition are discussed. (c) 2005 Elsevier B.V. All rights reserved.