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

The UV and visible optical spectra (absorption, emission and luminescence excitation) of the Ho-doped CaO-Ga2O3-GeO2 glasses at room and liquid nitrogen temperatures have been investigated for the first time. The Ho-doped (C-Ho = 0.7 wt%) glass samples with garnet Ca3Ga2Ge3O12 (or 3CaO-Ga2O3-3GeO(2)) composition were prepared by the conventional high -temperature synthesis technique. By optical and EPR spectroscopy it has been shown that the holmium impurity is incorporated into the glass network as Ho3+ (4f(10), 518) ions, exclusively. All transitions of the Ho3+ ions observed in optical spectra of Ho-doped 3CaO-Ga2O3-3GeO(2) glasses are identified. The Ho3+ optical absorption spectrum has been analyzed and described in the framework of Judd-Ofelt theory. Optical absorption and emission spectra of the Ho3+ ions in the 3CaO-Ga2O3-3GeO(2) glasses are quite similar to Ho3+ optical spectra in other oxide glasses and are characterized by statistical distribution of the local crystal field parameters. Incorporation peculiarities and spectroscopic properties of Ho3+ impurity ions in the glasses of CaO-Ga2O3-GeO2 system are discussed.