Crystal growth and spectroscopic analysis of Tm, Ho singly-doped and Tm/Ho co-doped CaLaGa3O7 NIR laser crystals

Growth of Tm, Ho singly-doped and Tm/Ho co-doped CaLaGa3O7 crystals by Czochralski method are investigated for the first time. The polarized absorption spectra, fluorescence spectra and luminescence decay curves of Tm: CaLaGa3O7, Ho: CaLaGa3O7 and Tm/Ho: CaLaGa3O7 crystals are reported. Based on the Judd-Ofelt theory and the polarized absorption spectra, the spontaneous transition probabilities, the fluorescent branching ratios and the radiative lifetimes were calculated. The crystals exhibit a broad emission band at about 2.0 μm, corresponding to 3F4→3H6 of Tm3+ and 5I7→5I8 of Ho3+, respectively. The energy transfer parameters in Tm/Ho: CaLaGa3O7 crystal between Tm3+ and Ho3+ are theoretically analyzed. These results show that Tm: CaLaGa3O7, Ho: CaLaGa3O7 and Tm/Ho: CaLaGa3O7 crystals are excellent potential tunable laser media for the ∼2.0 μm regions.