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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]

Abstract: Er3+-doped Gd2SiO5 (Er:GSO) single crystal with dimensions of ∅ 35×40mm3 has been grown by the Czochralski method. The absorption and fluorescence spectra of the Er:GSO crystal were measured at room temperature. The spectral parameters were calculated based on Judd–Ofelt theory, and the intensity parameters Ω 2, Ω 4 and Ω 6 are obtained to be 6.168×10−20, 1.878×10−20, and 1.255×10−20 cm2, respectively. The emission cross-section has been calculated by Fuechtbauer–Ladenbury formula. [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: Growth-induced defects in Yb:FAP crystals grown by the Czochralski method have been investigated by optical microscopy, chemical etching, scanning electron microscopy (SEM) and energy-dispersive spectroscopy (EDS). Anisotropic etching features have been observed on two FAP crystal planes: (0001) and . The shape of etch pits on the (0001) plane is hexagonal, while the etch pits on the plane have a variety of irregular shapes. It is also found that the density of etch pit varies along the boule. Based on the experimental observations, the formation mechanisms of growth defects are discussed, and methods for reducing the growth-induced defect concentration is proposed. [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 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: Yb: YAlO3 (YAP) (15at%) and Yb: Y3Al5O12 (YAG)(15at%) have been grown using the Czochralski method. Their absorption and fluorescence spectra were measured at room temperature and important spectroscopic parameters were calculated. Through the comparison of spectroscopic parameters of Yb:YAP and Yb: YAG, all results indicate that 15at% Yb:YAP crystal is a potential candidate used for compact, efficient thin chip lasers when the laser output wavelength is 1012 or 1038nm. [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]

The high optical quality 5 at% doped Yb:YAG single crystals with diameter of 3 inches have been grown by temperature gradient technology (TGT). The segregation coefficient of Yb ions in TGT-grown 5 at% doped Yb:YAG crystals determined by ICP-AES method is equal to 1.1. The absorption spectra in the range of 190–1200 nm of TGT-grown Yb:YAG crystals were also measured at the room temperature. The absorption peaks of trivalent Yb ions and the unknown color centers were found in the absorption spectra. [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: Nd,Co:LaMgAl11O19 (abbreviated as Co,Nd:LMA) was grown using the Czochralski method. The structure, polarized absorption spectrum, fluorescence spectrum, and fluorescence decay time were analyzed. The as-grown crystal had very wide absorption bands at 794nm, which can be pumped by GaAs laser diode without temperature stabilization. Two strong emission bands were present at 1056nm and 1082nm with full-width at half-maximum (FWHM) of 6 and 8nm, respectively. The large FWHM is due to the inhomogeneity of the Nd ion sites. The lifetimes of the 4F3/2 manifold of Co,Nd:LMA at room temperature monitored at 905nm, 1056nm, and 1344nm were 292, 288, and 350μs, respectively, which was caused by the different contribution of the three different sites with D3h and C2v symmetry. The absorption band of Co is from 1.3μm to 1.6μm, and Co,Nd:LMA still has a strong emission around the 1.38μm, indicating that the Co,Nd:LMA can be applied as a potential self-Q-switched material operating at 1.3μm. [Copyright &y& Elsevier]

Abstract: A laser crystal Er3+:YbVO4 has been grown by the Czochralski method with excellent quality. The rocking curve from the (004) diffraction plane of the as-grown Er3+:YbVO4 crystal was measured and the full-width at half-maximum value was found to be 19.80in. for the (004) face. The effective segregation coefficient of Er3+ was studied by X-ray fluorescence and the crystal structure was determined by means of X-ray diffraction analysis. The polarized absorption spectra and the fluorescence spectra of Er3+:YbVO4 were measured at room temperature. The spectral parameters were calculated based on the Judd–Ofelt theory, and the intensity parameters Ω 2, Ω 4 and Ω 6 are found to be 5.50×10−20, 1.96×10−20 and 2.34×10−20 cm2, respectively. The emission cross-section has been calculated by the Fuechtbauer–Ladenbury method. The spectroscopic parameters of Er3+:YbVO4 are compared with other typical laser hosts. [Copyright &y& Elsevier]

Abstract: Ytterbium-doped calcium pyroniobate single crystal has been grown for the first time. Spectral properties of Yb: Ca2Nb2O7 were investigated by emission and absorption spectra. Its cooperative luminescence and fluorescence lifetime were also studied. Yb ions in Ca2Nb2O7 showed very broad absorption and emission bandwidth and relatively large absorption and emission cross-sections. Along with other optical properties, this Yb-doped crystal would be a potential self-frequency doubling femtosecond laser gain material. [Copyright &y& Elsevier]

Abstract: Nano Y2O3 particles with a spherical shape and narrow size distribution have been prepared by a novel spray combustion method. The experimental procedure is briefly described and the thermodynamical process of the post-heat treatment is investigated in this paper. The precursor fully crystallized when treated at as low as 400 °C. Prepared particles showed spherical shape and well dispersibility under different treating conditions. Narrow size distribution of particles was achieved even when the precursor was treated at 1373K. [Copyright &y& Elsevier]

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]

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]

Abstract: The effects of Na+ doping level on the thermal conductivities, absorption and emission spectra, and fluorescence lifetimes of Yb3+,Na+:CaF2 crystals were systematically studied. Sites structure, covalent force, and crystal field strength of Yb3+:CaF2 crystals were markedly varied by codoping Na+ as charge compensator. The 2.0at% Yb3+ and 3.0at% Na+-codoped CaF2 crystal was demonstrated to operate in diode-pumped passively mode-locking scheme. Transform-limited 1ps laser pulses were obtained, showing the crystal capable of producing ultra-short laser pulses. [Copyright &y& Elsevier]