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Five atomic percent Yb:YAG laser crystals have been grown by Czochralski (CZ) and temperature gradient technique (TGT) method. The absorption spectra of as-grown and annealed Yb:YAG crystals have been investigated. There is no Yb2+ and color center absorption in TGT-grown Yb:YAG crystals; the absorption peak of CZ-grown Yb:YAG crystals after O2-annealing at 255 nm is attributed to Fe3+ ions. The longitudinal distribution of Yb3+ ions has also been studied; TGT-grown Yb:YAG crystal has a larger distributing inhomogeneity of Yb3+ although it is large sized. [Copyright &y& Elsevier]

Abstract: The Yb (10%):GGG and Yb (30%): GGG crystals have been grown by the Czochralski method. The chemical compositions are: Yb1.07Gd1.74Ga5.19O12 and Yb0.33Gd2.47Ga5.2O12. The absorption and emission spectra of Yb:GGG crystal at room temperature have been measured. The spectroscopic parameters of Yb:GGG and Yb:YAG have been compared. Optical absorption spectra of Yb:GGG show 4f–4f transitions related to Gd3+ ion around 300nm, and also an onset of charge transfer (CT) transitions from oxygen ligands to Gd3+ or Yb3+ cations below 240nm.The CT absorption of Yb3+ is largely overlapped by that of Gd3+ ions. [Copyright &y& Elsevier]

Abstract: Gd2SiO5 (GSO) single crystal codoped with Yb3+ and Er3+ (Abbr. as Er:Yb:GSO) was successfully grown by the Czochralski (CZ) method for the first time and the spectral characteristics were investigated. The absorption and fluorescence spectra were measured. The emission lifetime of the 4I13/2–Er-level was measured to be 5.84ms and the emission cross-section at 1529nm was calculated to be 1.03×10−20 cm2. The results indicate that Er:Yb:GSO is a potential laser material at ∼1.55μm wavelength region. [Copyright &y& Elsevier]