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 Er 3 + ions (amount of Er-0.7 wt.%) in glasses with garnet Ca 3 Ga 2 Ge 3 O 1 2 (or 3CaO-Ga 2 O 3 -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 Er 3 + ions (4f 1 1 electron configuration, 4 I 1 5 / 2 free ion ground state), exclusively. All observed transitions of the Er 3 + ions in glasses with 3CaO-Ga 2 O 3 -3GeO 2 composition in the UV-visible spectral region were identified. Optical spectra of the Er 3 + ions can be analysed in the framework of Judd-Ofelt theory. The Er 3 + luminescence decay curve for 4 S 3 / 2 → 4 I 1 5 / 2 transition (λ m a x = 555 nm) obtained at room temperature was satisfactory described by two-exponential approximation with lifetimes τ 1 = 10.6 μs and t 2 = 22.4 μs. The peculiarities of spectroscopic properties, luminescence kinetics and local structure of the Er 3 + centres in the glasses with 3CaO-Ga 2 O 3 -3GeO 2 composition are discussed.