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Abstract: Sm:CaNb2O6 single crystal has been grown by the Czochralski method. Its high-temperature X-ray powder diffraction, optical absorption, emission spectroscopic as well as lifetime have been studied. Thermal expansion coefficients (α), J–O parameters (Ω i ), radiative lifetime (τ rad), branching ratios (β) and stimulated emission cross-sections (σ e) were calculated. The quantum efficiency (η) was calculated to be 97%. The intense peak emission cross section at 610, 658nm were calculated to be 2.40×10−21, 2.42×10−21 cm2. These results indicate that Sm:CaNb2O6 crystal has potential use in visible laser and photonic devices area. [Copyright &y& Elsevier]

Abstract: The YAG crystal codoped with Yb3+ and Tm3+ has been grown by Czochralski (Cz) method. The crystal structure of the crystal has been determined by X-ray diffraction analysis. The absorption and emission spectra of Yb,Tm:YAG crystal at room temperature have also been studied. The emission cross-sections have been calculated by Fuechtbauer-Ladenburg formula and reciprocity method. [Copyright &y& Elsevier]

Abstract: Absorption and emission spectral properties of GdVO4 single crystal doped with Ho3+ ions were investigated at room temperature. Polarized absorption cross section is calculated in the range of 400–2200nm. Results were analyzed and parameters were calculated based on Judd-Ofelt theory, the emission spectrum shows that the emission intensity around the wavelength of 546nm associated with transition 5S2 → 5I8 is much stronger than other bands in the observed range and potentially enable the green light output around this emission band in this crystal. [Copyright &y& Elsevier]

The Czochralski crystal growth of 50 at.% Yb:YAG single crystal was reported. The absorption spectrum, emission spectrum and fluorescence lifetime of Yb:YAG crystal were measured at room temperature. The spectroscopic parameters of nominal 50 at.% Yb:YAG crystal were compared with that of Yb:YAG crystal with low doping level. The results indicate that Yb:YAG crystals with high doping level are potential candidates used for compact, efficient thin chip lasers. [Copyright &y& Elsevier]

Abstract: In this paper, a Yb3+ doped Lu3ScAl4O12 single crystal has been grown by the Czochralski method. The cell parameters were analyzed with X-ray diffraction (XRD). The absorption spectrum, emission spectrum and fluorescence lifetime of Yb:Lu3ScAl4O12 crystal were measured at room temperature. The absorption bandwidth, emission bandwidth, absorption cross-section, emission cross-section and fluorescence lifetime have been estimated as 25nm, 12.6nm, 0.54×10−20 cm2, 1.47×10−20 cm2 and 1.43ms. The spectral properties of Yb:Lu3ScAl4O12 crystal were compared with those of Yb:Lu3Al5O12 (Yb:LuAG) crystal. The results indicate that Yb:Lu3ScAl4O12 crystal should be a potential candidate used for generating short pulses in mode-locking operation. [Copyright &y& Elsevier]

The spectral properties of lightly doped Er:CaF 2 and Er,Pr:CaF 2 single crystals were investigated. Benefited from particular clustering effect, 2.79 μm continuous-wave (CW) laser operation was demonstrated in lightly doped 3 at.% Er:CaF 2 crystal. After co-doping small amount of Pr 3+ , the lifetime gap between Er 3+ : 4 I 11/2 and Er 3+ : 4 I 13/2 was shortened from 7.86 ms to about 1 ms. Moreover, the near-infrared and up-conversion fluorescence were significantly quenched. Thus, the CW laser performance was greatly improved. The slope efficiency was effectively improved from 8.0% to 15.8%. [ABSTRACT FROM AUTHOR]

Abstract: Nanorod spinel MnFe2O4 was synthesized by seed–hydrothermal route (combine hydrothermal method with seed growth method). XRD, Mössbauer spectroscopy, SEM, TEM, EDX and VSM were used to investigate the characters of the MnFe2O4. The obtained ferrite exhibited a uniform nanorod shape with 25–40nm in diameter and 300–400nm in length. The formation of the nanorod ferrite was explained as the inducement of seed, and the temperature of synthesizing 1-D ferrite by this method was lower than that without seed. All elements distributed equably along the rod axis. The crystal structure of obtained MnFe2O4 was high symmetry and partial of spinel inversion. In addition, the as-prepared ferrite showed a high saturation magnetization (M s =72.45emug−1) at room temperature and had a high photocatalytic activity (67.18%) to Methylene blue (MB). [Copyright &y& Elsevier]

Abstract: The rod-shaped La0.7Sr0.3MnO3 (LSMO) nanorods are prepared by a simple solid-state route, in which KMnO4 and MnCl2 are used as raw materials to prepare the precursor of MnO2 fibres. The diameter of as-obtained LSMO rods is about 50nm and their length longer than 10μm. We found that there is a close relation between morphology and the conditions of synthesis for LSMO preparing by MnO2 fibres as seeds. The process of the rods growth is observed by calcining the samples at different temperatures and periods of time. In the rods growth process, many small aggregates formed containing large numbers of rods in a low temperature (lower than 950°C). These aggregates then broke up to form a large number of individual LSMO rods (950°C, 5h). Finally, the rods changed into cubic particles with prolonging treatment time to more than 5h at 950°C. [Copyright &y& Elsevier]

Abstract: A novel energy- and time-saving solution combustion method has been developed to prepare Eu:Y2O3 nano-crystalline phosphor. This novel method employs anhydrous ethanol as solvent and fuel. The prepared nano-crystals after heat-treatment own narrow size distribution, well dispersibility and sinterability, confirmed by XRD, TEM and FTIR. The emission spectra of nano-Eu:Y2O3 samples show clear nano-size related phenomena. [Copyright &y& Elsevier]

Pr3+-doped Sr 0.5 La 0.5 Mg 0.5 Al 11.5 O 19 (ASL) crystal along 〈100〉 direction was successfully grown using the Czochralski technique under azote atmosphere. Absorption and emission spectra of Pr:ASL crystal have been measured at room temperature. Continuous-wave laser operation of the a-cut and c-cut Pr:ASL samples under InGaN laser diode pumping has been demonstrated. For deep red laser operation at about 726 nm, the maximum output powers achieved from a-cut sample was 92.8 mW with slope efficiency of about 11.9%, while 46.6 mW with slope efficiency of 8.0% for the c-cut sample. For red laser at about 645 nm, maximum output powers of 49.2 mW and 42.8 mW were obtained for the a-cut sample and c-cut sample, corresponding to a slope efficiency of 6.7% and 8.5%, respectively. • Pr:Sr 0.5 La 0.5 Mg 0.5 Al 11.5 O 19 crystal was successfully grown using the Czochralski method. • Spectral parameters of Pr:Sr 0.5 La 0.5 Mg 0.5 Al 11.5 O 19 crystal were obtained. • Red and deep red laser were demonstrated in Pr:Sr 0.5 La 0.5 Mg 0.5 Al 11.5 O 19 crystal. [ABSTRACT FROM AUTHOR]

This study aims to investigate the role of Y 3+ ion on microstructure, optical transmittance, and thermal properties of CaF 2 transparent ceramics. Series of nanosized CaF 2 powders doped with different concentration of Y 3+ ion were synthesized by direct precipitation method. XRD, FSEM and TEM results demonstrated that the CaF 2 nanoparticles could be tuned in size through doping of Y 3+ ion. Corresponding CaF 2 transparent ceramics were fabricated by hot-pressed (HP) method. Compared with the undoped CaF 2 sample, the transmittance of the CaF 2 ceramics improved dramatically after doping with Y 3+ ions and reached above 80% at the wavelength of 1200 nm. The effects of Y 3+ ion on the microstructure and thermal properties of CaF 2 transparent ceramics were also investigated. Overall consideration of the transmittance and thermal properties of the samples, the optimal concentration of Y 3+ ion was about 1 at.%. [ABSTRACT FROM AUTHOR]

• After co-doping Tb3+ ions, the Ω4/Ω6 increased 1.57 from to 1.66. • The branching ratios of the 3H 4 →3F 4 transition also strengthened. • The decay curve of 3F 4 level doped with different Tb3+ ions concentration decreased. • Tb3+ ion is a productive deactivator that could reduce the filling of 3F 4 mainfold and enhance the emission of 3H 4 →3F 4 transition. Tm3+ and Tb3+ co-doped Y 3 Al 5 O 12 (YAG) ceramics were fabricated by high temperature solid state reaction under oxygen sintering. The absorption spectra, fluorescence spectra and fluorescence decay curves of Tm,Tb:YAG ceramics were measured. The spectral parameters of Tm,Tb:YAG ceramic were calculated. The lifetimes of Tm3+:3F 4 level of Tm,Tb:YAG ceramics were calculated to be 11.28, 2.12, 1.24, 0.63 and 0.49 ms for the Tb3+ doping concentration of 0, 0.1, 0.2, 0.35 at 0.5 at%, respectively. The co-doping Tb3+ ion is a productive deactivator that could reduce the filling of 3F 4 mainfold and enhance the emission of 3H 4 →3F 4 transition. These results indicate that the addition of Tb3+ ions in Tm,Tb:YAG ceramic could be a promising technique for laser operation around 1.5 µm. [ABSTRACT FROM AUTHOR]

• A series of 0.6 at% Pr:CaF 2 -RF 3 (R= Y3+, Gd3+, Lu3+) crystals were successfully grown by the temperature gradient technique(TGT) method. • By co-doping R3+ ion (R=Y3+, Gd3+, Lu3+), the spectral performance of the crystals could be significantly improved and the function effect is also different. • The spectral performance and spectral quality factor of the crystals were systematically described and compared for the first time. • The spectral modulation effect caused by Y3+, Gd3+ and Lu3+ co-doping ion was discussed. A series of 0.6 at% Pr:CaF 2 -RF 3 (R = Y3+, Gd3+, Lu3+) crystals have been successfully grown by the temperature gradient technique(TGT). The absorption spectra, fluorescence spectra, and fluorescence decay curves were measured and analyzed at room temperature. When the R3+ concentration is higher than a certain value, the diffraction peaks of Pr:CaF 2 -RF 3 crystals were well indexed to the (Ca,Y)F 2 phase. By co-doping R3+ ion (R=Y3+, Gd3+, Lu3+), the spectral performance of the crystals could be significantly improved and the function effect is also different. For 0.6 at% Pr, 28.5 at% Y:CaF 2 crystal, the fluorescence lifetime of 3P 0 energy level was fitted to be 45.46 µs, and the emission cross sections of 3P 0 →3H 6 (605 nm), and 3P 0 →3F 2 (641 nm) were calculated to be 1.78 × 10−20 cm2, and 4.61 × 10−20 cm2 with the full width at half (FWHM) of 20.1 nm and 6.8 nm, respectively. The 0.6 at% Pr, 28.5 at% Y:CaF 2 crystal could be favorble laser medium for ultra-fast laser opreration at 605 nm and 641 nm. For 0.6 at% Pr, 18 at% Gd:CaF 2 and 0.6 at% Pr, 10 at% Lu:CaF 2 crystals, the spectral quality factors σ em• τ f of 3P 0 →3F 2 transition (642 nm) were calculated to be 614.18 × 10−20 cm2•µs and 506.36 × 10−20 cm2•µs with the FWHM of 3.7 nm and 5.3 nm. All the results show that 0.6 at% Pr, 18 at% Gd:CaF 2 and 0.6 at% Pr, 10 at% Lu:CaF 2 crystals are promising gain media for high-efficiency visible laser output at 642 nm, which would compete with commercial Pr: YLF crystal in the future. [ABSTRACT FROM AUTHOR]

Abstract: Spectroscopic properties of lutetium aluminum garnet Lu3Al5O12 (LuAG) single crystal doped with 1at.% of Pr3+ were investigated. The crystal was grown by the Czochralski method. Optical absorption, emission, excitation spectra and luminescence decay curves were recorded for this system in 5–500K temperature range. Excitation spectra in VUV–UV range (150–330nm) were also measured exploiting synchrotron radiation. It has been found that among bands of luminescence related to the 3PJ, 1D2 → 3HJ, 3FJ transition of Pr3+ in the visible region the 3P0 → 3H4 one, occurring ca. 488nm, is the most prominent. Luminescence lifetimes for the 3P0,1 and 1D2 levels were estimated to be 13 and 200μs respectively (at room temperature). VUV-excited emission spectrum stretches over the whole visible region. It has been concluded that the material under study is a promising phosphor that can be efficiently pumped by broad absorption bands centered at 240 and 280nm. [Copyright &y& Elsevier]