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Abstract: Crystals of Ce3+-doped (Lu x Y1−x )3Al5O12 (LuYAG) have been grown and studied by X-ray powder diffraction, emission spectroscopy, excitation spectroscopy and X-ray excited fluorescence spectroscopy. The X-ray powder diffraction pattern revealed that the as-grown LuYAG:Ce crystal possessed the garnet structure. Compared with Ce3+-doped Y3Al5O12 (YAG), the absorption bands associated with the 4f–5d transition shifted to shorter wavelengths, the emission band that originated from a transition from the lowest 5d level to the 2F ground state of the Ce3+ ions shifted to the blue, which was probably due to a larger Stokes shift of the emission, and the reduction of relative intensity of antisite defect emission in the X-ray excited fluorescence spectra revealed that introducing Lu ions into YAG could reduce the antisite defect. [Copyright &y& Elsevier]

Abstract: A Yb3+-doped CaYAlO4 laser crystal has been grown by the Czochralski technique. The segregation coefficient was measured by Inductively Coupled Plasma Atomic Emission Spectrometry (ICP-AES). The cell parameters were analyzed with X-ray diffraction experiments. Color defects in Yb:CaYAlO4 have been evidenced to be similar to those in undoped CaYAlO4. The polarized absorption spectra and the fluorescence spectrum of the Yb:CaYAlO4 crystal were measured at room temperature. The fluorescence decay time of the Yb3+ ion was investigated. The results show that Yb:CaYAlO4 has potential as a laser gain medium for an ultrashort laser system. [Copyright &y& Elsevier]

The absorption spectra, emission under 940 nm excitation by laser diode, and fluorescence lifetimes of as-grown and annealed Cr,Yb:YAG crystal have been investigated at room temperature. The increase of absorption coefficients at 941 and 1030 nm and the quenching of Yb3+ emission intensity and fluorescence lifetime after annealing are due to the increase of the concentration of Cr4+ ions. The data of thermal expansion and specific heat of the crystal have been measured. The thermal expansion coefficient is α=8.71×10−6 /K. The specific heat is 89.9 cal/mol K at 320.5 K. [Copyright &y& Elsevier]

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]

The stoichiometric laser crystal Yb3Al5O12 has been grown by the Czochralski method. The structure of the YbAG crystal has been determined by X-ray diffraction analysis. The absorption and emission spectra of YbAG crystal at room temperature have also been studied. The absorption, emission cross-section and fluorescence lifetime have been estimated as 0.64×10−20, 1.96×10−20 cm2 and 270 μs, respectively. The spectroscopic parameters of Yb:YAG and YbAG crystal have been compared, and the results indicate that YbAG is a promising stoichiometric laser crystal. [Copyright &y& Elsevier]

Yb3xY3(1−x)Al5O12 crystals with different Yb3+ concentration have been grown by the Czochralski method. The distribution coefficient of Yb3+ is 1.08±0.01, and it has little relation with Yb3+ concentration. The lattice parameter of YbAG is 1.193799±0.000054 nm. We have found an equation connecting the lattice parameter and Yb3+ concentration: α(x)=1.200976−0.007072x nm. [Copyright &y& Elsevier]

Abstract: A high optical quality erbium doped Lu2SiO5 single crystal has been grown by the Czochralski method. The distribution coefficient of Er3+ was measured to be ∼0.926. The absorption and emission spectra as well as the fluorescence decay curve of the excited state 4I13/2 were measured at room temperature. The spectroscopic parameters were calculated using the Judd–Ofelt theory, and the J–O parameters Ω 2 , Ω 4 and Ω 6 were found to be 4.451×10-20, 1.614×10-20 and 1.158×10-20 cm2, respectively. The room-temperature fluorescence lifetime of the Er3+ 4I13/2→4I15/2 transition was measured to be 7.74ms. The absorption and emission cross-section as well as the gain cross-section in the eye-safe regime of 1400–1700nm were also determined and discussed. [Copyright &y& Elsevier]

Abstract: A large and transparent Yb:FAP crystal with dimensions up to ∅30mm×85mm has been grown by the Czochralski method. The preparation of the raw material has been investigated. X-ray power diffraction studies of Yb:FAP crystal confirm that the as-grown crystal is isostructural with the FAP crystal. The crystalline quality has been studied using X-ray rocking curve analysis. The segregation coefficient of Yb3+ in the Yb:FAP crystal has been also determined. Linear thermal expansion coefficients in [001] and [100] directions have been measured in the 30–800°C temperature range. [Copyright &y& Elsevier]

Abstract: The high optical quality Tm: YAG single crystals with dopant concentrations of 2, 4, 8 at % Tm3+ ions have been grown by the Czochralski (CZ) method .The segregation coefficients of Tm3+ ions in CZ-grown 2, 4, 8 at % doped Tm: YAG crystals determined by ICP-AES method are equal to 0.93, 1.04, 1.10, respectively. The absorption spectra in the range of 190–900nm and the IR absorption spectra in the range of 1000–4500cm-1 of the Tm: YAG crystals were also measured at room temperature. The results indicate that Tm: YAG is favorable for laser diode-pumped system, and air annealing can improve the quality of the Tm: YAG crystal. [Copyright &y& Elsevier]

Tm-doped (Sc 0.5 Y 0.5 ) 2 SiO 5 (SYSO) crystals were grown by Czochralski method. The UV-VIR-NIR absorption spectra and the near-infrared emission spectra were measured and analysed by the Judd-Ofelt approach. Temperature influence on both absorption and emission spectra has been determined from the data recorded at room temperature and 10 K. It has been found that the structural disorder resulting from dissimilar ionic radii of Sc 3+ and Y 3+ in the solid solution (Sc 0.5 Y 0.5 ) 2 SiO 5 crystal brings about a strong inhomogeneous broadening of Tm 3+ ions spectra. However, it affects the excited state relaxation dynamics inherent to thulium-doped Y 2 SiO 5 and Sc 2 SiO 5 hosts weakly. [ABSTRACT FROM AUTHOR]

Abstract: For the first time, a high optical quality Yb3+-doped lutetium pyrosilicate laser crystal Lu2Si2O7 (LPS) was grown by the Czochralski (Cz) method. The segregation coefficient of ytterbium ion in Yb:LPS crystal detected by the inductively coupled plasma atomic emission spectrometer (ICP-AES) method is equal to 0.847. X-ray powder diffraction result confirms the C2/m phase monoclinic space group of the grown crystal and the peaks corresponding to different phases were indexed. The absorption and fluorescence spectra, as well as fluorescence decay lifetime of Yb3+ ion in LPS have been investigated. The absorption and fluorescence cross-sections of the transitions 2F7/2↔2F5/2 of Yb3+ ion in LPS crystal have been determined. The advantages of the Yb:LPS crystal including high crystal quality, quasi-four-level laser operating scheme, high absorption cross-sections (1.33×10−20 cm2) and particularly broad emission bandwidth (∼62nm) indicated that the Yb:LPS crystal seemed to be a promising candidate used as compact, efficient thin chip lasers when LD is pumped at 940 and 980nm due to its low-symmetry monoclinic structure and single crystallographic site. [Copyright &y& Elsevier]