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 3CaO–Ga2O3–3GeO2) 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 (4f11 electron configuration, 4I15/2 free ion ground state), exclusively. All observed transitions of the Er3+ ions in glasses with 3CaO–Ga2O3–3GeO2 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 4S3/2 → 4I15/2 transition (λmax = 555 nm) obtained at room temperature was satisfactory described by two-exponential approximation with lifetimes τ1 = 10.6 μs and τ2 = 22.4 μs. The peculiarities of spectroscopic properties, luminescence kinetics and local structure of the Er3+ centres in the glasses with 3CaO–Ga2O3–3GeO2 composition are discussed.