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Sample records for lu yb crystal

  1. Thermal expansion, heat capacity and magnetostriction of RAl3 (R = Tm, Yb, Lu) single crystals

    SciTech Connect

    Bud'ko, S.; Frenerick, J.; Mun, E.; Canfield, P.; Schmiedeshoff, G.

    2007-12-13

    We present thermal expansion and longitudinal magnetostriction data for cubic RAl{sub 3} (R = Tm, Yb, Lu) single crystals. The thermal expansion coefficient for YbAl{sub 3} is consistent with an intermediate valence of the Yb ion, whereas the data for TmAl{sub 3} show crystal electric field contributions and have strong magnetic field dependences. de Haas-van Alphen like oscillations were observed in the magnetostriction data for YbAl{sub 3} and LuAl{sub 3}, several new extreme orbits were measured and their effective masses were estimated. Specific heat data taken at 0 and 140 kOe for both LuAl{sub 3} and TmAl{sub 3} for T {le} 200 K allow for the determination of a crystal electric field splitting scheme for TmAl{sub 3}.

  2. Forward to cryogenic temperature: laser cooling of Yb: LuLiF crystal

    NASA Astrophysics Data System (ADS)

    Zhong, Biao; Luo, Hao; Lei, Yongqing; Shi, Yanling; Yin, Jianping

    2017-06-01

    The high quality Yb-doped fluoride crystals have broad prospects for optical refrigeration. We have laser cooled the Yb:LuLiF crystal to a temperature below the limit of current thermoelectric coolers ( 180 K). The 5% Yb:LuLiF crystal sample has a geometry of 2 mm×2 mm×5 mm and was supported by two fibers of 200 μm in diameter. They were placed in a 2×10-4 Pa vacuum chamber with an environment temperature of 294.5 K. The 1019 nm CW laser of power 38.7 W was adopted to irradiate the sample. The temperature of the sample was measured utilizing the DLT methods. After 20 minutes of laser irradiation, the 5% Yb:LuLiF crystal sample was cooled down to 182.4 K. By further optimizing experimental conditions and increasing the doped Yb concentration, the Yb:LuLiF crystal might be optically cooled below the cryogenic temperature of 123K in the near future.

  3. Laser cooling of Yb³⁺-doped LuLiF₄ crystal.

    PubMed

    Zhong, Biao; Yin, Jigang; Jia, Youhua; Chen, Lin; Hang, Yin; Yin, Jianping

    2014-05-01

    In order to meet the demands for applications of optical refrigerators in the fields of spaceflight, aviation, space science, and detection, a 2 wt. % Yb3+-doped LuLiF4 crystal, as a new laser cooling material, was prepared and demonstrated by using a 178 mW diode laser centered at 1015 nm and a resonant extra-cavity scheme with an enhancement factor of 12.8. Cooling efficiency of 1.27% and a temperature drop of 14.3 K/W are obtained with 79% of the incident laser power being absorbed. Based on our results, a sample with background absorption of α=4.2×10(-4)  cm(-1) can be potentially cooled down to ∼145 K. Our investigation shows that Yb3+-doped LuLiF4 crystal is potentially a promising candidate for solid-state refrigeration.

  4. Investigation of Yb-doped LiLuF4 single crystals for optical cooling

    NASA Astrophysics Data System (ADS)

    Volpi, Azzurra; Cittadino, Giovanni; Di Lieto, Alberto; Cassanho, Arlete; Jenssen, Hans P.; Tonelli, Mauro

    2017-01-01

    Optical cooling of solids, relying on annihilation of lattice phonons via anti-Stokes fluorescence, is an emerging technology that is rapidly advancing. The development of high-quality Yb-doped fluoride single crystals definitely led to cryogenic and sub-100-K operations, and the potential for further improvements has not been exhausted by far. Among fluorides, so far the best results have been achieved with Yb-doped LiYF4 (YLF) single crystals, with a record cooling to 91 K of a stand-alone YLF:10%Yb. We report on preliminary investigation of optical cooling of an LiLuF4 (LLF) single crystal, an isomorph of YLF where yttrium is replaced by lutetium. Different samples of 5% Yb-doped LLF single crystals have been grown and optically characterized. Optical cooling was observed by exciting the Yb transition in single-pass at 1025 nm and the cooling efficiency curve has been measured detecting the heating/cooling temperature change as a function of pumping laser frequency.

  5. Tuning of structure and enhancement of upconversion luminescence in NaLuF4:Yb(3+),Ho(3+) crystals.

    PubMed

    Lin, Hao; Xu, Dekang; Li, Anming; Teng, Dongdong; Yang, Shenghong; Zhang, Yueli

    2015-07-15

    A series of NaLuF4:Yb(3+),Ho(3+) nano/micro-crystals with different crystal structures were synthesized via a hydrothermal method using citric acid as a chelating agent. The influences of NaF content, Li(+) doping, reaction temperature and reaction time on the crystal structure and shape of the as-synthesized NaLuF4 crystals were systematically investigated. To the best of our knowledge, it is the first time to report Li(+) doped α-NaLuF4:Yb(3+),Ho(3+) nanocrystals and the phase transformation by introducing Li(+) in NaLuF4 crystals. As for Li(+) doped α-NaLuF4, UC luminescence intensities of green emission (538 nm) and red emission (644 nm) in α-NaLuF4:Yb(3+),Ho(3+) nanocrystals with 20 mol% Li(+) doping are enhanced by 20 and 3.5 times compared to their Li(+)-free counterpart. As for Li(+) doped α/β-mixed NaLuF4, with the increase of Li(+) content, the phase transforms from the α/β-mixed phase to hexagonal then to cubic. UC emissions of 538 nm and 644 nm in NaLuF4:Yb(3+),Ho(3+) crystals doped with 5 mol% Li(+) are enhanced by 26.5 and 23 times, respectively. Besides, it is found that with the higher temperature and prolonged time, the morphology of NaLuF4 changes from nanoparticles to microtubes, resulting in the dramatic increase of UC emission intensity. The effects of Li(+) doping, reaction temperature and reaction time on the enhancement of UC emission intensity are discussed in detail. This study provides an effective and facile approach to obtain nano/micro-crystals with controllable structures and excellent optical properties.

  6. Efficient passively Q-switched miniature Yb:Lu3Ga5O12 crystal laser

    NASA Astrophysics Data System (ADS)

    Han, Wenjuan; Chen, Xiaowen; Xia, Linhua; Wu, Kui; Zhang, Huaijin; Wang, Shiwu; Liu, Junhai

    2015-08-01

    A passively Q-switched miniature Yb:Lu3Ga5O12 crystal laser is demonstrated under 935-nm diode pumping, producing an average output power of 3.21 W at 1035 nm at a pulse repetition frequency of 26.3 kHz, with optical-to-optical and slope efficiencies being 36.5% and 60%, respectively. With the output coupling being increased and the initial transmission of the saturable absorber being lowered, an output power of 1.61 W at 1026 nm is generated at 8.3 kHz, the resulting pulse energy, duration and peak power were respectively 194 μJ, 2.5 ns and 77.6 kW.

  7. {Y 3- x,Yb x}[Ga] 2(Ga) 3O 12 and {Lu 2Yb 1}[Al] 2(Al) 3O 12 single crystals for scintillator application grown by the modified micro-pulling-down method

    NASA Astrophysics Data System (ADS)

    Yoshikawa, Akira; Akagi, Tadahiro; Nikl, Martin; Solovieva, Natalia; Lebbou, Kheirreddine; Dujardin, Christophe; Pédrini, Christian; Fukuda, Tsuguo

    2002-06-01

    In order to investigate proper hosts for charge transitions (CT) of Yb 3+, the gallium garnet host (YGG) and aluminium garnet host (LuAG) were studied. Transparent and crack-free heavily Yb-doped YGG, i.e. {Y 3- x,Yb x}[Ga] 2(Ga) 3O 12, x=0.15, 0.5, 1.0 and heavily Yb-doped LuAG, i.e. {Lu 2Yb 1}[Al] 2(Al) 3O 12 single crystals were grown by the modified pulling-down method with <1 1 1> orientation. Emission, excitation spectra and decay kinetics were measured for these crystals. The CT of Yb 3+ in the YGG host were discussed compared with the Yb 3+ one in the LuAG host.

  8. Thermal properties measurement and laser operation of a new Yb: Gd0.68Lu0.32VO4 crystal.

    PubMed

    Zhang, Huaijin; Yu, Yonggui; Cheng, Yan; Wang, Jiyang; Tao, Xutang; Jiang, Minhua; Xia, Huirui

    2008-07-21

    A new series mixed vanadate crystals, Yb:Gd(x)Lu(1-x)VO(4) (x=0.2, 0.35, 0.53, 0.68 and 0.84), were grown by the Czochralski method. The thermal conductivities of these crystals were measured from room temperature to 280?C, and the thermal conductivities of Yb:Gd(0.68)Lu(0.32)VO(4) at room temperature are 6.4 and 6.9 W m(-1)K(-1) along a- and c-axis, respectively. The material constants of Yb:Gd(x)Lu(1-x)VO(4) series crystals were estimated. The properties of Yb:Gd(x)Lu(1-x)VO(4) series crystals were compared with those of Yb:LuVO(4) and Yb:GdVO(4) crystals. Laser output power of 1.25 W at 1031 nm was obtained with a slope efficiency of 26% by use of diode pumping for Yb:Gd(0.68)Lu(0.32)VO(4) crystal.

  9. Spectroscopic and laser properties of Er(3+):Yb(3+):LuAl(3)(BO(3))(4) crystal at 1.5-1.6 microm.

    PubMed

    Chen, Yujin; Lin, Yanfu; Huang, Jianhua; Gong, Xinghong; Luo, Zundu; Huang, Yidong

    2010-06-21

    An Er(3+):Yb(3+):LuAl(3)(BO(3))(4) crystal doped with 24.1 at.% Yb(3+) and 1.1 at.% Er(3+) ions was grown by the flux method. The polarized spectroscopic properties related to the operation of 1.5-1.6 microm laser of the crystal were evaluated at room temperature. The laser properties of a 0.7-mm-thick, c-cut crystal were investigated in diode-end-pumped hemispherical and plano-plano cavities, respectively. Compared with those of Er(3+):Yb(3+):YAl(3)(BO(3))(4) crystal obtained under similar experimental conditions, higher maximum output peak power, higher slope efficiency, and lower threshold were achieved in the Er(3+):Yb(3+):LuAl(3)(BO(3))(4) crystal.

  10. Spectroscopic properties and ultrafast performance of Yb:CaLu x Gd1-x AlO4 crystal

    NASA Astrophysics Data System (ADS)

    Hu, Qiangqiang; Su, Xiancui; Wang, Yiran; He, Jingliang; Zhang, Baitao; Jia, Zhitai; Tao, Xutang

    2017-04-01

    A systematical investigation of the spectroscopic and ultrafast performance of Yb:CaLu x Gd1-x AlO4 crystal (Yb:CLGA) was reported first in this work. A SESAM-based mode-locking laser was achieved by self-starting, generating reliable pulses as short as 69.6 fs. At a central wavelength of 1054 nm, a maximum average output power of 232 mW was obtained with the highest peak power of 63.7 kW. The same crystal was employed in wavelength tunable operation, and 65.7 nm of tuning range between 1023.1 nm and 1088.8 nm was obtained with a resolution of sub-0.1 nm.

  11. Two-step photoconductivity in LiY x Lu1 - x F4:Ce,Yb crystals

    NASA Astrophysics Data System (ADS)

    Nurtdinova, L. A.; Korableva, S. L.; Leontiev, A. V.

    2016-10-01

    Photoconductivity of LiY x Lu1- x F4:Ce,Yb ( x = 0-1) crystals is measured under one- and two-step excitation. It is established that the photoconductivity is due to intra-center transitions from excited states of Ce3+ ions. The position of the ground 4 f-state of Ce3+ ion relative to the bottom of the conduction band is determined. The choice of pumping conditions to obtain the lasing on the 5 d-4 f transitions of trivalent cerium in these active media is substantiated.

  12. Kerr-Lens Self-Mode-Locked Laser Characteristics of Yb:Lu2SiO5 Crystal

    NASA Astrophysics Data System (ADS)

    Liu, Jie; Yang, Ji-Min; Wang, Wei-Wei; Zheng, Li-He; Su, Liang-Bi; Xu, Jun

    2011-07-01

    A diode-pumped Kerr-lens self-mode-locked laser is achieved by using Yb: Lu2SiO5(Yb:LSO) crystal without additional components. Under the incident pump power of 14.44 W, a self-mode-locked output power of 2.98 W is obtained in the five-mirror cavity, corresponding to an optical-optical efficiency of 20.6%. Pulses as short as 8.2 ps are realized at 1059 nm, with the corresponding pulse energy and peak power of 28.9 nJ and 3.5 kW, respectively. A pair of SF10 prisms are inserted into the laser cavity to compensate for the group velocity dispersion. The pulse width is compressed to 2.2 ps with an average output power of 1.25 W.

  13. Yb:Lu2SiO5 crystal : characterization of the laser emission along the three dielectric axes

    NASA Astrophysics Data System (ADS)

    Toci, Guido; Pirri, Angela; Beitlerova, Alena; Shoji, Yasuhiro; Yoshikawa, Akira; Hybler, Jiri; Nikl, Martin; Vannini, Matteo

    2015-05-01

    Yb:doped Lu2SiO5 (Lutetium orthosilicate, LSO) is an optically biaxial crystal with laser emission in the range 1000- 1100 nm. It features different absorption and emission spectra for polarization along its three dielectric axes. In this work we have characterized the laser emission properties of Yb:LSO along all the three dielectric axis, evidencing differences that can be exploited in the design of ultrafast laser sources. The material was tested in a longitudinally pumped laser cavity. The laser emission efficiency was found similar along all the three dielectric axes, with slope efficiencies around 90% in most cases. Regarding the tuning range, for the most favourable polarization direction we obtained a continuously tunable emission between 993 and 1088 nm (i. e. 95 nm) peaked at 1040 nm. The tuning curves along the three dielectric axes spanned similar ranges but with relevant differences in the shape.

  14. 760  fs diode-pumped mode-locked laser with Yb:LuAG crystal at 1032  nm.

    PubMed

    Su, Xian-Cui; Wang, Yi-Ran; He, Jing-Liang; Zhao, Ru-Wei; Zhang, Pei-Xiong; Hang, Yin; Hou, Jia; Zhang, Bai-Tao; Zhao, Shuang

    2015-08-10

    In this study, we experimentally demonstrate the generation of 760 fs pulse duration from a diode-pumped Yb:LuAG mode-locked laser at 1032 nm. At the repetition rate of 58.6 MHz, the maximum average power of 1.07 W was obtained, corresponding to the peak power of 24 kW. To our knowledge, these results represent the shortest pulse duration and highest peak power ever obtained for a 1032 nm mode-locked laser with Yb:LuAG crystal.

  15. Plate-shaped Yb:LuPO4 crystal for efficient CW and passively Q-switched microchip lasers

    NASA Astrophysics Data System (ADS)

    Liu, Junhai; Wang, Lisha; Han, Wenjuan; Xu, Honghao; Zhong, Degao; Teng, Bing

    2016-10-01

    It is demonstrated that plate-shaped crystals of Yb:LuPO4, which are grown from spontaneous nucleation by high-temperature solution method, can be utilized to make microchip lasers operating in continuous-wave (CW) or passively Q-switched mode. Efficient operation of such a microchip laser, which is built with a 0.3 mm thick crystal plate in a 2 mm long plane-parallel cavity, is realized at room temperature. With 2.37 W of pump power absorbed, 1.45 W of CW output power is generated with a slope efficiency of 73%. When passively Q-switched with a Cr4+:YAG crystal plate as saturable absorber, the laser produces a maximum pulsed output power of 0.53 W at 1013.3 nm, at a pulse repetition rate of 23.8 kHz, the resulting pulse energy, duration, and peak power are 22.3 μJ, 4.0 ns, and 5.6 kW, respectively.

  16. Yb doping concentration and temperature influence on Yb:LuAG thermal lensing

    NASA Astrophysics Data System (ADS)

    Veselský, Karel; Šulc, Jan; Jelínková, Helena; Nejezchleb, Karel; Škoda, Václav

    2016-03-01

    The aim of this study was to investigate whether refractive power of thermal lens for Yb:LuAG crystal at cryogenic temperatures depends on Yb doping concentration which has not been examined yet. The three measured Yb:LuAG laser rods samples (length of 3 mm, diameter 3 mm, AR @ 0.94 μm and 1.03 μm, doping concentration 5.4, 8.4 and 16.6 at. % Yb/Lu) were mounted in the temperature controlled copper holder of the liquid nitrogen cryostat. Samples were longitudinally pumped with fiber coupled CW laser diode at 0.930 μm with the focal point 0.4 mm in diameter. The 38 mm long semi-hemispherical laser resonator consisted of a flat pump mirror (HR @ 1.03 μm and HT 0.94 μm) and curved output coupler (r=500 mm) of reflectivity 94 % @ 1.06 μm. The refractive power of thermal lens was estimated indirectly by measuring of change in the position of focused laser beam focal point. The measurement was performed for constant absorbed power of 10 W in temperature range from 80 up to 240 K. It was observed that cryogenic cooling caused reduction of thermal lens power, which increased linearly with increasing temperature. For temperatures from 80 to 160 K refractive power was identical for all concentration. For higher temperature the refractive power of thermal lens increased with increasing Yb3+ concentration. Presented study shows that application of cryogenic temperature leads to reduction of thermal effect even for high dopant concentration in Yb:LuAG crystal. This is essential for reaching of high output power while maintaining high beam quality.

  17. Passively Q-switched oscillation at 1005–1012 nm of a miniature Yb:LuPO4 crystal rod laser

    NASA Astrophysics Data System (ADS)

    Wang, Lisha; Han, Wenjuan; Xu, Honghao; Zhong, Degao; Teng, Bing; Liu, Junhai

    2017-04-01

    A diode pumped Yb:LuPO4 miniature crystal rod laser operating at wavelengths of 1005.0–1012.5 nm, which was passively Q-switched with a Cr4+:YAG saturable absorber, was demonstrated. An average output power of 7.2 W at 1012.5 nm was generated at a pulse repetition rate of 166.7 kHz, with optical-to-optical and slope efficiencies being 38.5% and 45%, respectively. Under conditions of higher output coupling and lower initial transmission of the saturable absorber, an output power of 2.9 W at wavelengths around 1005.0 nm could be reached at 19.2 kHz, the resulting pulse energy, duration and peak power were respectively 151 µJ, 3.0 ns and 50.3 kW.

  18. Nonlinear spectroscopic properties of Yb3+-doped sesquioxides Lu2O3 and Sc2O3.

    PubMed

    Soulard, R; Moncorgé, R; Zinoviev, A; Petermann, K; Antipov, O; Brignon, A

    2010-05-24

    We report on the measurements of near-UV excited-state absorption (ESA) spectra and refractive index changes (RICs) in the two ytterbium doped laser crystals Yb:Lu2O3 and Yb:Sc2O3. ESA is assigned to ligand-to-metal charge transfer (LMCT) absorption transitions and RICs to the polarizability changes experienced by the Yb3+ ions due to these strong electric-dipole allowed absorption bands.

  19. Rare-earth metal gallium silicides via the gallium self-flux method. Synthesis, crystal structures, and magnetic properties of RE(Ga1-xSix)2 (RE=Y, La-Nd, Sm, Gd-Yb, Lu)

    NASA Astrophysics Data System (ADS)

    Darone, Gregory M.; Hmiel, Benjamin; Zhang, Jiliang; Saha, Shanta; Kirshenbaum, Kevin; Greene, Richard; Paglione, Johnpierre; Bobev, Svilen

    2013-05-01

    Fifteen ternary rare-earth metal gallium silicides have been synthesized using molten Ga as a molten flux. They have been structurally characterized by single-crystal and powder X-ray diffraction to form with three different structures—the early to mid-late rare-earth metals RE=La-Nd, Sm, Gd-Ho, Yb and Y form compounds with empirical formulae RE(GaxSi1-x)2 (0.38≤x≤0.63), which crystallize with the tetragonal α-ThSi2 structure type (space group I41/amd, No. 141; Pearson symbol tI12). The compounds of the late rare-earth crystallize with the orthorhombic α-GdSi2 structure type (space group Imma, No. 74; Pearson symbol oI12), with refined empirical formula REGaxSi2-x-y (RE=Ho, Er, Tm; 0.33≤x≤0.40, 0.10≤y≤0.18). LuGa0.32(1)Si1.43(1) crystallizes with the orthorhombic YbMn0.17Si1.83 structure type (space group Cmcm, No. 63; Pearson symbol oC24). Structural trends are reviewed and analyzed; the magnetic susceptibilities of the grown single-crystals are presented.

  20. Lu3+/Yb3+ and Lu3+/Er3+ co-doped antimony selenide nanomaterials: synthesis, characterization, and electrical, thermoelectrical, and optical properties

    PubMed Central

    2013-01-01

    Lu3+/Yb3+ and Lu3+/Er3+ co-doped Sb2Se3 nanomaterials were synthesized by co-reduction method in hydrothermal condition. Powder X-ray diffraction patterns indicate that the LnxLn′xSb2−2xSe3 Ln: Lu3+/Yb3+ and Lu3+/Er3+ crystals (x = 0.00 − 0.04) are isostructural with Sb2Se3. The cell parameters were increased for compounds upon increasing the dopant content (x). Scanning electron microscopy and transmission electron microscopy images show that co-doping of Lu3+/Yb3+ ions in the lattice of Sb2Se3 produces nanorods, while that in Lu3+/Er3+ produces nanoparticles, respectively. The electrical conductivity of co-doped Sb2Se3 is higher than that of the pure Sb2Se3 and increases with temperature. By increasing the concentration of Ln3+ions, the absorption spectrum of Sb2Se3 shows red shifts and some intensity changes. In addition to the characteristic red emission peaks of Sb2Se3, emission spectra of co-doped materials show other emission bands originating from f-f transitions of the Yb3+ ions. PMID:23537193

  1. Crystal growth of Yb 3+-doped oxide single crystals for scintillator application

    NASA Astrophysics Data System (ADS)

    Yoshikawa, Akira; Nikl, Martin; Ogino, Hiraku; Lee, Jong-Ho; Fukuda, Tsuguo

    2003-03-01

    Long emission wavelength scintillators are strongly required from the viewpoint of the practical use of silicon photo-diode, which has higher resolution with lower cost compared with photo-multipllier. Among the various scintillator emission centers, we regard emission from Yb 3+ charge-transitions state (CTS) as a candidate. In order to investigate proper hosts for Yb 3+ CTS, the yttrium gallium garnet host and lutetium aluminum garnet host were studied. Transparent and crack-free heavily Yb-doped YGG, i.e. {Y 1- xYb x} 3[Ga] 2(Ga) 3O 12 (Yb: YGG, x=0.15, 0.5, 1.0) and heavily Yb-doped LuAG, i.e. {Lu 1- xYb x} 3[Al] 2(Al) 3O 12 (Yb: LuAG, x=0.15, 0.5, 1.0) single crystals could be grown by the Modified Pulling Down method with <1 1 1> orientation. Emission, excitation spectra and decay kinetics were measured for these crystals. The CT transition of Yb 3+ in the yttrium gallium garnet host was discussed compared with the Yb 3+ one in the lutetium aluminum garnet host.

  2. New microarchitectures of (Er,Yb):Lu2O3 nanocrystals embedded in PMMA: synthesis, structural characterization, and luminescent properties

    PubMed Central

    2013-01-01

    We report the formation of two-dimensional disordered arrays of poly(methyl)methacrylate (PMMA) microcolumns with embedded single size distribution of Lu0.990Er0.520Yb0.490 nanocrystals, (Er,Yb):Lu2O3, using a disordered porous silicon template. The cubic (Er,Yb):Lu2O3 nanocrystals, which crystallize into the cubic system with Ia3¯ space group, were synthesized using the modified Pechini method. Electronic microscopic techniques were used to study the distribution of the nanocrystals in the PMMA columns. Cathodoluminescence was used to observe the visible luminescence of the particles. Red emission attributed to 4 F9/2 → 4I15/2 erbium transition is predominant in these new composites. PMID:24034270

  3. An Yb3+-doped Lu2SiO5 mode-locked laser using a reflective graphene oxide absorber

    NASA Astrophysics Data System (ADS)

    Feng, Chao; Liu, Jie; Wang, Yonggang; Zheng, Lihe; Su, Liangbi; Xu, Jun

    2013-06-01

    Reflective graphene oxide played the part of the saturable absorber to achieve a continuous wave mode-locking (CWML) laser based on Yb3+:Lu2SiO5 (Yb:LSO) crystal for the first time. The laser operated at a repetition frequency of 87 MHz at a maximum average output power of 0.95 W with a single pulse energy of 10.9 nJ. A 9.8 ps ultra-short pulse was yielded at 1058 nm with a full width at half maximum (FWHM) of 2.09 nm, corresponding to a peak power of 1.11 kW.

  4. CW and tunable performances of Yb3+:LuAG transparent ceramics with different doping concentrations

    NASA Astrophysics Data System (ADS)

    Ma, Chaoyang; Zhu, Jiangfeng; Liu, Kai; Wen, Zicheng; Ma, Ran; Long, Jiaqi; Yuan, Xuanyi; Cao, Yongge

    2017-07-01

    We report the CW laser operation and wavelength tunability of 10 at%, 15 at% and 20 at% Yb3+-doping LuAG ceramics pumped at 970 nm. The absorption saturation effects were taken into account herein. For 10 at% Yb3+-doping sample, the maximum slop efficiency and output power was 60.7% and 1.8 W, respectively. Furthermore, the slop efficiencies of 52.3% (15 at%) and 46.5% (20 at%) were reported. What's more, the maximum optical-to-optical efficiency for our samples was determined to be 40.1%, 36.8%, and 33.1% at the incident pump power of 4 W, respectively. The round-trip cavity loss of the laser system based on our Yb3+:LuAG ceramics were evaluated. The tuning curve of a 20 at% Yb3+:LuAG ceramic extended from 1018 nm up to 1062 nm, and that of 10 at% and 15 at% samples became much more broader, making Yb3+:LuAG ceramics possible candidates for ultrashort pulse generation.

  5. Rare-earth metal gallium silicides via the gallium self-flux method. Synthesis, crystal structures, and magnetic properties of RE(Ga1–xSix)₂ (RE=Y, La–Nd, Sm, Gd–Yb, Lu)

    SciTech Connect

    Darone, Gregory M.; Hmiel, Benjamin; Zhang, Jiliang; Saha, Shanta; Kirshenbaum, Kevin; Greene, Richard; Paglione, Johnpierre; Bobev, Svilen

    2013-05-01

    Fifteen ternary rare-earth metal gallium silicides have been synthesized using molten Ga as a molten flux. They have been structurally characterized by single-crystal and powder X-ray diffraction to form with three different structures—the early to mid-late rare-earth metals RE=La–Nd, Sm, Gd–Ho, Yb and Y form compounds with empirical formulae RE(GaxSi1–x)₂ (0.38≤x≤0.63), which crystallize with the tetragonal α-ThSi₂ structure type (space group I4₁/amd, No. 141; Pearson symbol tI12). The compounds of the late rare-earth crystallize with the orthorhombic α-GdSi₂ structure type (space group Imma, No. 74; Pearson symbol oI12), with refined empirical formula REGaxSi2–x–y (RE=Ho, Er, Tm; 0.33≤x≤0.40, 0.10≤y≤0.18). LuGa₀.₃₂₍₁₎Si₁.₄₃₍₁₎ crystallizes with the orthorhombic YbMn₀.₁₇Si₁.₈₃ structure type (space group Cmcm, No. 63; Pearson symbol oC24). Structural trends are reviewed and analyzed; the magnetic susceptibilities of the grown single-crystals are presented. - Graphical abstract: This article details the exploration of the RE–Ga–Si ternary system with the aim to systematically investigate the structural “boundaries” between the α-ThSi₂ and α-GdSi₂-type structures, and studies of the magnetic properties of the newly synthesized single-crystalline materials. Highlights: • Light rare-earth gallium silicides crystallize in α-ThSi₂ structure type. • Heavy rare-earth gallium silicides crystallize in α-GdSi₂ structure type. • LuGaSi crystallizes in a defect variant of the YbMn₀.₁₇Si₁.₈₃ structure type.

  6. Crystal structure and vibrational properties of RFe3(BO3)4 (R = Ce - Lu) ferroborate crystal: ab initio calculations

    NASA Astrophysics Data System (ADS)

    Petrov, V. P.; Chernyshev, V. A.; Nikiforov, A. E.

    2016-12-01

    The ab initio calculations of the crystal structure and lattice dynamics of ferroborate crystal family RFe3(BO3)4 (R = Ce, Pm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu), S.G. R32, has been carried out within the framework of the MO LCAO approach by using density functional theory and effective 4f-in-core pseudopotential for rare earth element. The fully optimized geometry as well as vibrational frequencies has been calculated.

  7. High-energy, ceramic-disk Yb:LuAG laser amplifier.

    PubMed

    Siebold, M; Loeser, M; Roeser, F; Seltmann, M; Harzendorf, G; Tsybin, I; Linke, S; Banerjee, S; Mason, P D; Phillips, P J; Ertel, K; Collier, J C; Schramm, U

    2012-09-24

    We report the first short-pulse amplification results to several hundred millijoule energies in ceramic Yb:LuAG. We have demonstrated ns-pulse output from a diode-pumped Yb:LuAG amplifier at a maximum energy of 580 mJ and a peak optical-to-optical efficiency of 28% at 550 mJ. In cavity dumped operation of a nanosecond oscillator we obtained 1 mJ at up to 100 Hz repetition rate. A gain bandwidth of 5.4 nm was achieved at room temperature by measuring the small-signal single-pass gain. Furthermore, we compared our results with Yb:YAG within the same amplifier system.

  8. Investigation of the Energy-Transfer Mechanism in Ho(3+)- and Yb(3+)-Codoped Lu2O3 Phosphor with Efficient Near-Infrared Downconversion.

    PubMed

    Xiang, Guotao; Ma, Yan; Zhou, Xianju; Jiang, Sha; Li, Li; Luo, Xiaobing; Hao, Zhendong; Zhang, Xia; Pan, Guo-Hui; Luo, Yongshi; Zhang, Jiahua

    2017-02-06

    A high-temperature solid-state method was used to synthesize the Ho(3+)- and Yb(3+)-codoped cubic Lu2O3 powders. The crystal structures of the as-prepared powders were characterized by X-ray diffraction. The energy-transfer (ET) phenomenon between Ho(3+) ions and Yb(3+) ions was verified by the steady-state spectra including visible and near-infrared (NIR) regions. Beyond that, the decay curves were also measured to certify the existence of the ET process. The downconversion phenomena appeared when the samples were excited by 446 nm wavelength corresponding to the transition of Ho(3+): (5)I8→(5)G6/(5)F1. On the basis of the analysis of the relationship between the initial transfer rate of Ho(3+): (5)F3 level and the Yb(3+) doping concentration, it indicates that the ET from (5)F3 state of Ho(3+) ions to (2)F5/2 state of Yb(3+) ions is mainly through a two-step ET process, not the long-accepted cooperative ET process. In addition, a 62% ET efficiency can be achieved in Lu2O3: 1% Ho(3+)/30% Yb(3+). Unlike the common situations in which the NIR photons are all emitted by the acceptors Yb(3+), the sensitizers Ho(3+) also make contributions to the NIR emission upon 446 nm wavelength excitation. Meanwhile, the (5)I5→(5)I8 transition and (5)F4/(5)S2→(5)I6 transition of Ho(3+) as well as the (2)F5/2→(2)F7/2 transition of Yb(3+) match well with the optimal spectral response of crystalline silicon solar cells. The current research indicates that Lu2O3: Ho(3+)/Yb(3+) is a promising material to improve conversion efficiency of crystalline silicon solar cell.

  9. Syntheses, structures, and vibrational spectroscopy of the two-dimensional iodates Ln(IO 3) 3 and Ln(IO 3) 3(H 2O) ( Lndbnd Yb, Lu)

    NASA Astrophysics Data System (ADS)

    Assefa, Zerihun; Ling, Jie; Haire, Richard G.; Albrecht-Schmitt, Thomas E.; Sykora, Richard E.

    2006-12-01

    The reaction of Lu 3+ or Yb 3+ and H 5IO 6 in aqueous media at 180 °C leads to the formation of Yb(IO 3) 3(H 2O) or Lu(IO 3) 3(H 2O), respectively, while the reaction of Yb metal with H 5IO 6 under similar reaction conditions gives rise to the anhydrous iodate, Yb(IO 3) 3. Under supercritical conditions Lu 3+ reacts with HIO 3 and KIO 4 to yield the isostructural Lu(IO 3) 3. The structures have been determined by single-crystal X-ray diffraction. Crystallographic data are (Mo Kα, λ=0.71073 Å): Yb(IO 3) 3, monoclinic, space group P2 1/ n, a=8.6664(9) Å, b=5.9904(6) Å, c=14.8826(15) Å, β=96.931(2)°, V=766.99(13), Z=4, R( F)=4.23% for 114 parameters with 1880 reflections with I>2 σ( I); Lu(IO 3) 3, monoclinic, space group P2 1/ n, a=8.6410(9), b=5.9961(6), c=14.8782(16) Å, β=97.028(2)°, V=765.08(14), Z=4, R( F)=2.65% for 119 parameters with 1756 reflections with I>2 σ( I); Yb(IO 3) 3(H 2O), monoclinic, space group C2/ c, a=27.2476(15), b=5.6296(3), c=12.0157(7) Å, β=98.636(1)°, V=1822.2(2), Z=8, R( F)=1.51% for 128 parameters with 2250 reflections with I>2 σ( I); Lu(IO 3) 3(H 2O), monoclinic, space group C2/ c, a=27.258(4), b=5.6251(7), c=12.0006(16) Å, β=98.704(2)°, V=1818.8(4), Z=8, R( F)=1.98% for 128 parameters with 2242 reflections with I>2 σ( I). The f elements in all of the compounds are found in seven-coordinate environments and bridged with monodentate, bidentate, or tridentate iodate anions. Both Lu(IO 3) 3(H 2O) and Yb(IO 3) 3(H 2O) display distinctively different vibrational profiles from their respective anhydrous analogs. Hence, the Raman profile can be used as a complementary diagnostic tool to discern the different structural motifs of the compounds.

  10. 8.5  W mode-locked Yb:Lu1.5Y1.5Al5O12 laser with master oscillator power amplifiers.

    PubMed

    Wang, Fuyong; Qin, Zhipeng; Xie, Guoqiang; Yuan, Peng; Qian, Liejia; Xu, Xiaodong; Xu, Jun

    2015-02-10

    We report on a diode-pumped passively mode-locked Yb:Lu(1.5)Y(1.5)Al(5)O(12) (Yb:LuYAG) laser for the first time to our knowledge. With the mixed crystal of Yb:LuYAG as gain medium, the mode-locked laser generated 2.2 W of average output power with a repetition rate of 83.9 MHz and pulse duration of 2.4 ps at the wavelength of 1030 nm. In order to obtain higher output power, the output from the mode-locked oscillator was further amplified to 8.5 W by two-stage single-pass amplifiers. The high-power picosecond laser is very useful for applications such as pumping of midinfrared optical parametric oscillators, material microprocessing, and UV light generation.

  11. Half-life measurement of the medical radioisotope 177Lu produced from the 176Yb(n,γ) reaction

    NASA Astrophysics Data System (ADS)

    Ferreira, K. M.; Collins, S. M.; Fenwick, A. J.

    2017-09-01

    177Lu is a medium energy beta-emitter commonly used in Nuclear Medicine for radiotherapeutic applications. In this work, the half-life of 177Lu has been measured using a re-entrant ionisation chamber over a period of 82 days (approximately 12 half-lives). Unlike the majority of previous studies, the material used in this work was produced via the 176Yb(n,γ)177Yb reaction followed by the β-decay to 177Lu, producing insignificant quantities of 177mLu. This has resulted in the most precise half-life measurement of 177Lu to date. A half-life of 6.6430 (11) days has been determined. This value is in statistical agreement with the currently recommended half-life of 6.6463 (15) days (z-score = 1.8).

  12. Morphology evolution and pure red upconversion mechanism of β-NaLuF4 crystals.

    PubMed

    Lin, Hao; Xu, Dekang; Li, Anming; Teng, Dongdong; Yang, Shenghong; Zhang, Yueli

    2016-06-16

    A series of β-NaLuF4 crystals were synthesized via a hydrothermal method. Hexagonal phase microdisks, microprisms, and microtubes were achieved by simply changing the amount of citric acid in the initial reaction solution. Pure red upconversion (UC) luminescence can be observed in β-NaLuF4:Yb(3+), Tm(3+), Er(3+) and Li(+) doped β-NaLuF4:20% Yb(3+), 1% Tm(3+), 20% Er(3+). Based on the rate equations, we report the theoretical model about the pure red UC mechanism in Yb(3+)/Tm(3+)/Er(3+) doped system. It is proposed that the pure red UC luminescence is mainly ascribed to the energy transfer UC from Tm(3+):(3)F4 → (3)H6 to Er(3+):(4)I11/2 → (4)F9/2 and the cross-relaxation (CR) effect [Er(3+):(4)S3/2 + (4)I15/2 → (4)I9/2 + (4)I13/2] rather than the long-accepted mechanism [CR process among Er(3+):(4)F7/2 + (4)I11/2 → (4)F9/2 + (4)F9/2]. In addition, compared to the Li(+)-free counterpart, the pure red UC luminescence in β-NaLuF4:20% Yb(3+), 1% Tm(3+), 20% Er(3+) with 15 mol% Li(+) doping is enhanced by 13.7 times. This study provides a general and effective approach to obtain intense pure red UC luminescence, which can be applied to other synthetic strategies.

  13. Morphology evolution and pure red upconversion mechanism of β-NaLuF4 crystals

    PubMed Central

    Lin, Hao; Xu, Dekang; Li, Anming; Teng, Dongdong; Yang, Shenghong; Zhang, Yueli

    2016-01-01

    A series of β-NaLuF4 crystals were synthesized via a hydrothermal method. Hexagonal phase microdisks, microprisms, and microtubes were achieved by simply changing the amount of citric acid in the initial reaction solution. Pure red upconversion (UC) luminescence can be observed in β-NaLuF4:Yb3+, Tm3+, Er3+ and Li+ doped β-NaLuF4:20% Yb3+, 1% Tm3+, 20% Er3+. Based on the rate equations, we report the theoretical model about the pure red UC mechanism in Yb3+/Tm3+/Er3+ doped system. It is proposed that the pure red UC luminescence is mainly ascribed to the energy transfer UC from Tm3+:3F4 → 3H6 to Er3+:4I11/2 → 4F9/2 and the cross-relaxation (CR) effect [Er3+:4S3/2 + 4I15/2 → 4I9/2 + 4I13/2] rather than the long-accepted mechanism [CR process among Er3+:4F7/2 + 4I11/2 → 4F9/2 + 4F9/2]. In addition, compared to the Li+-free counterpart, the pure red UC luminescence in β-NaLuF4:20% Yb3+, 1% Tm3+, 20% Er3+ with 15 mol% Li+ doping is enhanced by 13.7 times. This study provides a general and effective approach to obtain intense pure red UC luminescence, which can be applied to other synthetic strategies. PMID:27306720

  14. Morphology evolution and pure red upconversion mechanism of β-NaLuF4 crystals

    NASA Astrophysics Data System (ADS)

    Lin, Hao; Xu, Dekang; Li, Anming; Teng, Dongdong; Yang, Shenghong; Zhang, Yueli

    2016-06-01

    A series of β-NaLuF4 crystals were synthesized via a hydrothermal method. Hexagonal phase microdisks, microprisms, and microtubes were achieved by simply changing the amount of citric acid in the initial reaction solution. Pure red upconversion (UC) luminescence can be observed in β-NaLuF4:Yb3+, Tm3+, Er3+ and Li+ doped β-NaLuF4:20% Yb3+, 1% Tm3+, 20% Er3+. Based on the rate equations, we report the theoretical model about the pure red UC mechanism in Yb3+/Tm3+/Er3+ doped system. It is proposed that the pure red UC luminescence is mainly ascribed to the energy transfer UC from Tm3+:3F4 → 3H6 to Er3+:4I11/2 → 4F9/2 and the cross-relaxation (CR) effect [Er3+:4S3/2 + 4I15/2 → 4I9/2 + 4I13/2] rather than the long-accepted mechanism [CR process among Er3+:4F7/2 + 4I11/2 → 4F9/2 + 4F9/2]. In addition, compared to the Li+-free counterpart, the pure red UC luminescence in β-NaLuF4:20% Yb3+, 1% Tm3+, 20% Er3+ with 15 mol% Li+ doping is enhanced by 13.7 times. This study provides a general and effective approach to obtain intense pure red UC luminescence, which can be applied to other synthetic strategies.

  15. Crystal growth and optical properties of Gd admixed Ce-doepd Lu2Si2O7 single crystals

    NASA Astrophysics Data System (ADS)

    Horiai, Takahiko; Kurosawa, Shunsuke; Murakami, Rikito; Yamaji, Akihiro; Shoji, Yasuhiro; Ohashi, Yuji; Pejchal, Jan; Kamada, Kei; Yokota, Yuui; Yoshikawa, Akira

    2017-06-01

    Ce-doped Lu2Si2O7 scintillator contains radioactive isotope 176Lu which causes an unwanted intrinsic background signal. The development of scintillators with reduced Lu concentration were required in some applications. In this study, we developed the Gd admixed lutetium pyrosilicate, where the average ion radius at the rare earth site was similar to the Tm3+ ion radius, for which the RE2Si2O7 (RE=Tm, Yb, Lu) crystal structure is stable from room temperature to melting point. We have grown (Cex Lu1-x-y Gdy)2Si2O7 (x=0.01, y=0.00, 0.05, 0.10) single crystals. Their crystal systems were monoclinic with a space group C2/m. The absorption spectra revealed the energy transitions in Ce and Gd ions might be occurred. The light output was degraded and decay time was accelerated comparing the Gd 5% admixed sample with the Gd 10% one.

  16. [Crystal growth and spectroscopy of Er/Yb:KGW crystal].

    PubMed

    Zhu, Zhao-jie; Tu, Chao-yang; Li, Jian-fu; Wu, Bai-chang; Huang, Yan

    2005-09-01

    The Er3 /Yb3+:KGW crystal with the dimensions of 30 mm x 25 mm x 15 mm was grown from K2W2O7 solvent by modified Czochralski method. The absorption spectrum was measured at room temperature and its absorption peaks were assigned. The emission spectrum was obtained under the excitation of 980 nm. There are two broad emission bands at 1024 and 1535 nm, whose FHWM are 60 and 36 nm respectively. It shows that this crystal is suitable for InGaAs LD pumping, and may be a promising laser crystal tunable at near 1 024 and 1 535 nm.

  17. Growth and characterization of LuVO4 single crystals

    NASA Astrophysics Data System (ADS)

    Dimitrov, D. Z.; Rafailov, P. M.; Chen, Y. F.; Lee, C. S.; Todorov, R.; Juang, J. Y.

    2017-09-01

    Large LuVO4 single crystals have been successfully obtained by high-temperature solution method. The structure details of these crystals are determined by X-ray crystallographic analysis and Raman spectroscopy. It is observed that the crystal consists of LuVO4 phase with trace amount of imperfections possibly due to oxygen vacancies. The optical quality of the crystal is assessed by Spectroscopic Ellipsometry (SE). The crystal shows higher than +0.2 birefringence in a large interval of wavelengths.

  18. CW and mode-locked operation of Yb(3+)-doped Lu3Al5O12 ceramic laser.

    PubMed

    Nakao, Hiroaki; Shirakawa, Akira; Ueda, Ken-ichi; Yagi, Hideki; Yanagitani, Takagimi

    2012-07-02

    CW laser operation and first mode-locked laser operation of Yb:LuAG ceramic are reported. Efficient CW laser operation was obtained with maximum output power of 2.14 W and a 72% slope efficiency. Femtosecond mode-locked laser operation was achieved with pulse duration of 699 fs and a 200 mW average output power.

  19. K{sub 3}Ln[OB(OH){sub 2}]{sub 2}[HOPO{sub 3}]{sub 2} (Ln=Yb, Lu): Layered rare-earth dihydrogen borate monohydrogen phosphates

    SciTech Connect

    Zhou Yan; Hoffmann, Stefan; Huang Yaxi; Prots, Yurii; Schnelle, Walter; Menezes, Prashanth W.; Carrillo-Cabrera, Wilder; Sichelschmidt, Joerg; Mi Jinxiao; Kniep, Ruediger

    2011-06-15

    Two isotypic layered rare-earth borate phosphates, K{sub 3}Ln[OB(OH){sub 2}]{sub 2}[HOPO{sub 3}]{sub 2} (Ln=Yb, Lu), were synthesized hydrothermally and the crystal structures were determined by single-crystal X-ray diffraction (R3-bar , Z=3, Yb: a=5.6809(2) A, c=36.594(5) A, V=1022.8(2) A{sup 3}, Lu: a=5.6668(2) A, c=36.692(2) A, V=1020.4(1) A{sup 3}). The crystal structure can be described in terms of stacking of Glaserite-type slabs consisting of LnO{sub 6} octahedra interlinked by phosphate tetrahedra and additional layers of [OB(OH){sub 2}]{sup -} separated by K{sup +} ions. Field and temperature dependent measurements of the magnetic susceptibility of the Yb-compound revealed Curie-Weiss paramagnetic behavior above 120 K ({mu}{sub eff}=4.7 {mu}{sub B}). Magnetic ordering was not observed down to 1.8 K. - Graphical abstract: Two isotypic layered rare-earth borate phosphates, K{sub 3}Ln[OB(OH){sub 2}]{sub 2}[HOPO{sub 3}]{sub 2} (Ln = Yb, Lu), were synthesized hydrothermally and the crystal structures were determined by single-crystal X-ray diffraction. The structure can be described by stacking of Glaserite-type slabs and dihydrogen borate layers separated by potassium cations. Highlights: > First hydrothermal synthesis of rare-earth borate phosphates. > Instead of microcrystalline powders the synthesis of single crystals was achieved. > Successful single-crystal X-ray structure determination. > 2D arrangement of magnetic rare-earth ions. > EPR spectrum of Yb{sup 3+} at 5 K.

  20. The surface study of ReFeO3 (Re =Lu, Yb) thin films by X-ray Photoemission Spectroscopy and Density Function Calculation

    NASA Astrophysics Data System (ADS)

    Cao, Shi; Paudel, Tula; Sinha, Kishan; Jiang, Xuanyuan; Wang, Wenbin; Tsymbal, Evgeny; Xu, Xiaoshan; Dowben, Peter

    2015-03-01

    The rare-earth ferrites, ReFeO3, may have a large magneto-electric response, with high surface/interface polarization, thus the surfaces are of considerable interest. We have characterized the surfaces of hexagonal ReFeO3 (Re = Lu, Yb) and orthorhombic LuFeO3 thin films by angle resolved X-ray photoemission spectroscopy (ARXPS) and compared with density function theory (DFT). The surfaces will terminate in either Fe-O or Re-O depending on whether in the hexagonal or orthorhombic phase of the rare earth ferrite, but consistent with the expectations of DFT. The orthorhombic or hexagonal phases of these rare earth ferrites have the Fe in different crystal fields, which in turn affects the of Fe-O ligands. These changes in electronegativity are experimentally evident as differences in the Fe 2p core level photoemission satellite features. Surface preparation also effects surface termination and will be discussed.

  1. Study of the thermo-optical constants of Yb doped Y2O3, Lu2O3 and Sc2O3 ceramic materials.

    PubMed

    Snetkov, Ilya L; Silin, Dmitry E; Palashov, Oleg V; Khazanov, Efim A; Yagi, Hideki; Yanagitani, Takagimi; Yoneda, Hitoki; Shirakawa, Akira; Ueda, Ken-Ichi; Kaminskii, Alexander A

    2013-09-09

    Thermally induced depolarization and thermal lens of three Konoshima Chemical Co. laser-ceramics samples Yb(3+):Lu(2)O(3)(C(Yb) ≈ 1.8 at.%), Yb(3+):Y(2)O(3)(C(Yb) ≈ 1.8 at.%), and Yb(3+):Sc(2)O(3) (C(Yb) ≈ 2.5 at.%) were measured in experiment at different pump power. The results allowed us to estimate the thermal conductivity of the investigated ceramic samples and compare their thermo-optical properties. The thermo-optical constants P and Q and its sign measured for these materials at the first time.

  2. Nanostructured crystals of fluorite phases Sr1 - x R x F2 + x ( R are rare-earth elements) and their ordering. I. Crystal growth of Sr1 - x R x F2 + x ( R = Y, La, Ce, Pr, Nd, Sm, Gd, Tb, Dy, Ho, Er, Tm, Yb, and Lu)

    NASA Astrophysics Data System (ADS)

    Sobolev, B. P.; Karimov, D. N.; Sul'Yanov, S. N.; Zhmurova, Z. I.

    2009-01-01

    Crystals of nonstoichiometric phases Sr1 - x R x F2 + x ( R are 14 rare-earth elements) and the ordered phase Sr4Lu3F17 with a trigonally distorted fluorite lattice were grown by the Bridgman method. Ten of 26 Sr1 - x R x F2 + x crystals, where R = La-Ho or Y, melt congruently. The isoconcentration series Sr0.90 R 0.10F2.10 includes four crystals with R = Er-Lu. The compositions corresponding to the maxima for the latter crystals were not determined. The concentration series, in which the mole fraction of RF3 varies from 10 to 50 mol %, were obtained for the crystals with R = La, Nd, and Gd. Most of the crystals are of good optical quality. To evaluate the composition changes in the course of crystal growth, the cubic unit-cell parameters were determined by X-ray powder diffraction. The line-broadening analysis revealed a nonmonotonic change of microdistortions as regards both the rare-earth content and rare-earth series. The changes in the lattice parameters and the congruent-melting points of the Sr1 - x R x F2 + x phases in the rare-earth series reflect the morphotropic transitions in the series of pure RF3 despite the fact that SrF2 dominates in nonstoichiometric fluorite crystals.

  3. Facile synthesis and multicolor luminescent properties of uniform Lu2O3:Ln (Ln=Eu3+, Tb3+, Yb3+/Er3+, Yb3+/Tm3+, and Yb3+/Ho3+) nanospheres.

    PubMed

    Li, Rumin; Gai, Shili; Wang, Liuzhen; Wang, Jun; Yang, Piaoping

    2012-02-15

    Multicolor Lu(2)O(3):Ln (Ln=Eu(3+), Tb(3+), Yb(3+)/Er(3+), Yb(3+)/Tm(3+), and Yb(3+)/Ho(3+)) nanocrystals (NCs) with uniform spherical morphology were prepared through a facile urea-assisted homogeneous precipitation method followed by a subsequent calcination process. X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), high-resolution transmission electron microscopy (HRTEM), energy-dispersive X-ray spectrum (EDS), Fourier transformed infrared (FT-IR), thermogravimetric and differential thermal analysis (TG-DTA), and photoluminescence (PL) spectra as well as kinetic decays were employed to characterize these samples. The XRD results reveal that the as-prepared nanospheres can be well indexed to cubic Lu(2)O(3) phase with high purity. The SEM images show the obtained Lu(2)O(3):Ln samples consist of regular nanospheres with the mean diameter of 95 nm. And the possible formation mechanism is also proposed. Upon ultraviolet (UV) excitation, Lu(2)O(3):Ln (Ln=Eu(3+) and Tb(3+)) NCs exhibit bright red (Eu(3+), (5)D(0)→(7)F(2)), and green (Tb(3+), (5)D(4)→(7)F(5)) down-conversion (DC) emissions. Under 980 nm NIR irradiation, Lu(2)O(3):Ln (Ln=Yb(3+)/Er(3+), Yb(3+)/Tm(3+), and Yb(3+)/Ho(3+)) NCs display the typical up-conversion (UC) emissions of green (Er(3+), (4)S(3/2),(2)H(11/2)→(4)I(15/2)), blue (Tm(3+), (1)G(4)→(3)H(6)) and yellow-green (Ho(3+), (5)F(4), (5)S(2)→(5)I(8)), respectively.

  4. LETTER TO THE EDITOR: Study of Yb3+-Yb3+ and Yb3+-Ce3+ energy transfer in Yb,Ce:CaGd4Si3O13 (Yb,Ce:CGS) crystals

    NASA Astrophysics Data System (ADS)

    Voroshilov, I. V.; Lebedev, V. A.; Gavrilenko, A. N.; Ignatiev, B. V.; Isaev, V. A.; Shestakov, A. V.

    2000-03-01

    The Yb radiative lifetime of 923 µs has been determined by the extrapolation to the zero concentration of Yb. Quenching of the Yb luminescence is observed in the Yb3+ ,Ce3+ :CaGd4 Si3 O13 (Yb,Ce:CGS) crystals due to their intrinsic defects and Ce3+ ions. The main quenching mechanism is the energy migration through Yb ions to the defects with a micro-parameter CDD (Yb-Yb) = 1.0 × 10-38 cm6 s-1 , and the Yb3+ icons/Journals/Common/to" ALT="to" ALIGN="TOP"/> Ce3+ energy transfer with a micro-parameter CDA = 5.5 × 10-44 cm6 s-1 .

  5. Spin reorientation, magnetization reversal, and negative thermal expansion observed in R F e0.5C r0.5O3 perovskites (R =Lu ,Yb ,Tm )

    NASA Astrophysics Data System (ADS)

    Pomiro, Fernando; Sánchez, Rodolfo D.; Cuello, Gabriel; Maignan, Antoine; Martin, Christine; Carbonio, Raúl E.

    2016-10-01

    Three members of the perovskite family R F e0.5C r0.5O3 (R =Lu ,Yb , and Tm) have been synthesized and characterized. A systematic study of the crystal and magnetic structures was performed by neutron powder diffraction combined with magnetization measurements. All these compounds crystallize in a Pbnm orthorhombic unit cell and they are already antiferromagnetic at room temperature. The study of the magnetic structure vs temperature showed the occurrence of a progressive spin reorientation from Γ4TM to Γ2TM for the transition metal sublattice, and in the Tm-based sample, a long-range magnetic order of the T m3 + sublattice was found (Γ8R) . These results are in excellent agreement with the magnetic susceptibility measurements. No spin reorientation is observed in the Lu-based sample for which a magnetization reversal at a compensation temperature Tcomp= 225 K was detected. A clear magnetostrictive effect was observed in the samples with R =Yb and Tm associated with a negative thermal expansion and was assigned to a magnetoelastic effect produced by repulsion between the magnetic moments of neighboring transition metal ions.

  6. Syntheses, structures, and vibrational spectroscopy of the two-dimensional iodates Ln(IO{sub 3}){sub 3} and Ln(IO{sub 3}){sub 3}(H{sub 2}O) (Ln =Yb, Lu)

    SciTech Connect

    Assefa, Zerihun . E-mail: zassefa@ncat.edu; Ling Jie; Haire, Richard G.; Albrecht-Schmitt, Thomas E.; Sykora, Richard E. . E-mail: rsykora@jaguar1.usouthal.edu

    2006-12-15

    The reaction of Lu{sup 3+} or Yb{sup 3+} and H{sub 5}IO{sub 6} in aqueous media at 180 {sup o}C leads to the formation of Yb(IO{sub 3}){sub 3}(H{sub 2}O) or Lu(IO{sub 3}){sub 3}(H{sub 2}O), respectively, while the reaction of Yb metal with H{sub 5}IO{sub 6} under similar reaction conditions gives rise to the anhydrous iodate, Yb(IO{sub 3}){sub 3}. Under supercritical conditions Lu{sup 3+} reacts with HIO{sub 3} and KIO{sub 4} to yield the isostructural Lu(IO{sub 3}){sub 3}. The structures have been determined by single-crystal X-ray diffraction. Crystallographic data are (MoK{alpha}, {lambda}=0.71073 A): Yb(IO{sub 3}){sub 3}, monoclinic, space group P2{sub 1}/n, a=8.6664(9) A, b=5.9904(6) A, c=14.8826(15) A, {beta}=96.931(2){sup o}, V=766.99(13), Z=4, R(F)=4.23% for 114 parameters with 1880 reflections with I>2{sigma}(I); Lu(IO{sub 3}){sub 3}, monoclinic, space group P2{sub 1}/n, a=8.6410(9), b=5.9961(6), c=14.8782(16) A, {beta}=97.028(2){sup o}, V=765.08(14), Z=4, R(F)=2.65% for 119 parameters with 1756 reflections with I>2{sigma}(I); Yb(IO{sub 3}){sub 3}(H{sub 2}O), monoclinic, space group C2/c, a=27.2476(15), b=5.6296(3), c=12.0157(7) A, {beta}=98.636(1){sup o}, V=1822.2(2), Z=8, R(F)=1.51% for 128 parameters with 2250 reflections with I>2{sigma}(I); Lu(IO{sub 3}){sub 3}(H{sub 2}O), monoclinic, space group C2/c, a=27.258(4), b=5.6251(7), c=12.0006(16) A, {beta}=98.704(2){sup o}, V=1818.8(4), Z=8, R(F)=1.98% for 128 parameters with 2242 reflections with I>2{sigma}(I). The f elements in all of the compounds are found in seven-coordinate environments and bridged with monodentate, bidentate, or tridentate iodate anions. Both Lu(IO{sub 3}){sub 3}(H and Yb(IO{sub 3}){sub 3}(H{sub 2}O) display distinctively different vibrational profiles from their respective anhydrous analogs. Hence, the Raman profile can be used as a complementary diagnostic tool to discern the different structural motifs of the compounds. - Graphical abstract: Four new metal iodates, Yb(IO{sub 3

  7. Measurement of gamow-teller strength for 176Yb --> 176Lu and the efficiency of a solar neutrino detector

    PubMed

    Bhattacharya; Goodman; Raghavan; Palarczyk; Garcia; Rapaport; van Heerden IJ; Zupranski

    2000-11-20

    We report a 0 degrees 176Yb(p,n)176Lu measurement at IUCF where we used 120 and 160 MeV protons and the energy dependence method to determine Gamow-Teller (GT) matrix elements relative to the model independent Fermi matrix element. The data show that there is an isolated concentration of GT strength in the low-lying 1(+) states making the proposed Low Energy Neutrino Spectroscopy detector (based on neutrino captures on 176Yb) sensitive to pp and 7Be neutrinos and a promising detector to resolve the solar neutrino problem.

  8. Measurement of Gamow-Teller Strength for 176Yb --> 176Lu and the Efficiency of a Solar Neutrino Detector

    NASA Astrophysics Data System (ADS)

    Bhattacharya, M.; Goodman, C. D.; Raghavan, R. S.; Palarczyk, M.; García, A.; Rapaport, J.; van Heerden, I. J.; Zupranski, P.

    2000-11-01

    We report a 0° 176Yb\\(p,n\\)176Lu measurement at IUCF where we used 120 and 160 MeV protons and the energy dependence method to determine Gamow-Teller (GT) matrix elements relative to the model independent Fermi matrix element. The data show that there is an isolated concentration of GT strength in the low-lying 1+ states making the proposed Low Energy Neutrino Spectroscopy detector (based on neutrino captures on 176Yb) sensitive to pp and 7Be neutrinos and a promising detector to resolve the solar neutrino problem.

  9. Hexagonal versus perovskite phase of manganite RMnO3 (R=Y,Ho,Er,Tm,Yb,Lu)

    NASA Astrophysics Data System (ADS)

    Zhou, J.-S.; Goodenough, J. B.; Gallardo-Amores, J. M.; Morán, E.; Alario-Franco, M. A.; Caudillo, R.

    2006-07-01

    The floating-zone method and high-pressure synthesis have been used to obtain the hexagonal and the perovskite RMnO3 (R=Y,Ho,Er,Tm,Yb,Lu) compounds. We have refined the crystal structure and characterized the compounds with measurements of magnetic susceptibility χ(T) and thermal conductivity κ(T) . The systematic change of κ(T) below TN found in all members of the hexagonal RMnO3 family shows that some spin-independent bond-length fluctuation plays an important role in the suppression of κ(T) below TN as well as in the paramagnetic phase. The responsible soft vibrational mode is identified. In contrast, the perovskite RMnO3 shows a phonon-like κ(T) below room temperature, but with an anomalously large critical scattering at TN . A phase diagram of transition temperatures versus the R3+ -ion radius for both hexagonal and perovskite phases is also given.

  10. Growth of YbFe2O4 single crystals exhibiting long-range charge order via the optical floating zone method

    NASA Astrophysics Data System (ADS)

    Williamson, H. L.; Mueller, T.; Angst, M.; Balakrishnan, G.

    2017-10-01

    We report the growth of YbFe2O4 single crystals via the floating zone technique, in four different oxygen partial pressures ranging from CO:CO2 = 1:5 to 1:2.5, for a cross comparison of stoichiometry effects. We obtained highly stoichiometric single crystals with sharp magnetic transitions as well as off-stoichiometric samples with smeared transitions. We also provide for the first time clear evidence of 3D long-range charge order correlations at room temperature in YbFe2O4 through high energy X-ray diffraction, identical to the analogous LuFe2O4. The correlation length obtained for YbFe2O4 in the c → direction is at least a factor of 5 larger than that observed in LuFe2O4.

  11. The crystal structure of Yb{sub 2}(SO{sub 4}){sub 3}.3H{sub 2}O and its decomposition product, {beta}-Yb{sub 2}(SO{sub 4}){sub 3}

    SciTech Connect

    Mills, Stuart J.; Petricek, Vaclav; Kampf, Anthony R.; Herbst-Imer, Regine; Raudsepp, Mati

    2011-09-15

    Yb{sub 2}(SO{sub 4}){sub 3}.3H{sub 2}O, synthesised by hydrothermal methods at 220(2) deg. C, has been investigated by single crystal X-ray diffraction. Yb{sub 2}(SO{sub 4}){sub 3}.3H{sub 2}O crystallises in space group Cmc2{sub 1} and is isostructural with Lu{sub 2}(SO{sub 4}){sub 3}.3H{sub 2}O. The crystal structure has been refined to R{sub 1}=0.0145 for 3412 reflections [F{sub o}>3{sigma}(F)], and 0.0150 for all 3472 reflections. The structure of Yb{sub 2}(SO{sub 4}){sub 3}.3H{sub 2}O is a complex framework of YbO{sub 6} octahedra, YbO{sub 8} and YbO{sub 5}(H{sub 2}O){sub 3} polyhedra and SO{sub 4} tetrahedra. Thermal data shows that Yb{sub 2}(SO{sub 4}){sub 3}.3H{sub 2}O decomposes between 120 and 190 deg. C to form {beta}-Yb{sub 2}(SO{sub 4}){sub 3}. The structure of a twinned crystal of {beta}-Yb{sub 2}(SO{sub 4}){sub 3} was solved and refined using an amplimode refinement in R3c with an R{sub 1}=0.0755 for 8944 reflections [F{sub o}>3{sigma}(F)], and 0.1483 for all 16,361 reflections. {beta}-Yb{sub 2}(SO{sub 4}){sub 3} has a unique structural topology based on a 3D network of pinwheels. - Graphical abstract: Octahedral-tetrahedral linkages found in Y{sub 2}(SO{sub 4}){sub 3} [and Er{sub 2}(SO{sub 4}){sub 3}] and ss-Yb{sub 2}(SO{sub 4}){sub 3}. Highlights: > The crystal structure and decomposition reactions of Yb{sub 2}(SO{sub 4}){sub 3}.3H{sub 2}O. > The crystal structure of a twinned crystal of {beta}-Yb{sub 2}(SO{sub 4}){sub 3}. > Comparison of the structures of {beta}-Yb{sub 2}(SO{sub 4}){sub 3} and Y{sub 2}(SO{sub 4}){sub 3}.

  12. Characterization of YbNi4(P1-xAsx)2, x = 0, 0.2 single crystals grown by Czochralski method

    NASA Astrophysics Data System (ADS)

    Kliemt, K.; Krellner, C.

    2017-04-01

    We have investigated large single crystals of YbNi4P2 that were grown from a levitating melt by the Czochralski method. The new samples facilitate the determination of the absolute values of the electrical resistivity. Phase pure polycrystalline samples of the non-magnetic reference LuNi4P2 were prepared and the electrical resistivity was measured. Furthermore we have grown a single crystal of the As substituted compound YbNi4(P1-xAsx)2, x = 0.2 and investigated the homogenity of the As distribution.

  13. Structure and thermal expansion of Lu2O3 and Yb2O3 up to the melting points

    DOE PAGES

    Pavlik, Alfred; Ushakov, Sergey V.; Navrotsky, Alexandra; ...

    2017-08-24

    Knowledge of thermal expansion and high temperature phase transformations is essential for prediction and interpretation of materials behavior under the extreme conditions of high temperature and intense radiation encountered in nuclear reactors. We studied the structure and thermal expansion of Lu2O3 and Yb2O3 were studied in oxygen and argon atmospheres up to their melting temperatures using synchrotron X-ray diffraction on laser heated levitated samples. Both oxides retained the cubic bixbyite C-type structure in oxygen and argon to melting. In contrast to fluorite-type structures, the increase in the unit cell parameter of Yb2O3 and Lu2O33 with temperature is linear within experimentalmore » error from room temperature to the melting point, with mean thermal expansion coefficients (8.5 ± 0.6) · 10-6 K-1 and (7.7 ± 0.6) · 10-6 K-1, respectively. There is no indication of a superionic (Bredig) transition in the C-type structure or of a previously suggested Yb2O3 phase transformation to hexagonal phase prior to melting.« less

  14. Structure and thermal expansion of Lu 2 O 3 and Yb 2 O 3 up to the melting points

    DOE PAGES

    Pavlik, Alfred; Ushakov, Sergey V.; Navrotsky, Alexandra; ...

    2017-08-24

    Knowledge of thermal expansion and high temperature phase transformations is essential for prediction and interpretation of materials behavior under the extreme conditions of high temperature and intense radiation encountered in nuclear reactors. We studied the structure and thermal expansion of Lu2O3 and Yb2O3 were studied in oxygen and argon atmospheres up to their melting temperatures using synchrotron X-ray diffraction on laser heated levitated samples. Both oxides retained the cubic bixbyite C-type structure in oxygen and argon to melting. In contrast to fluorite-type structures, the increase in the unit cell parameter of Yb2O3 and Lu2O33 with temperature is linear within experimentalmore » error from room temperature to the melting point, with mean thermal expansion coefficients (8.5 ± 0.6) · 10-6 K-1 and (7.7 ± 0.6) · 10-6 K-1, respectively. There is no indication of a superionic (Bredig) transition in the C-type structure or of a previously suggested Yb2O3 phase transformation to hexagonal phase prior to melting.« less

  15. Structure and thermal expansion of Lu2O3 and Yb2O3 to the melting temperatures

    DOE PAGES

    Pavlik III, Alfred; Ushakov, Sergey V.; Navrotsky, Alexandra; ...

    2017-11-01

    Knowledge of thermal expansion and high temperature phase transformations is essential for prediction and interpretation of materials behavior under the extreme conditions of high temperature and intense radiation encountered in nuclear reactors. Structure and thermal expansion of Lu2O3 and Yb2O3 were studied in oxygen and argon atmospheres up to their melting temperatures using synchrotron X-ray diffraction on laser heated levitated samples. Both oxides retained the cubic bixbyite C-type structure in oxygen and argon to melting. In contrast to fluorite-type structures, the increase in the unit cell parameter of Yb2O3 and Lu2O3 with temperature is linear within experimental error from roommore » temperature to the melting point, with mean thermal expansion coefficients (8.5 ± 0.6) · 10−6 K−1 and (7.7 ± 0.6) · 10−6 K−1, respectively. There is no indication of a superionic (Bredig) transition in the C-type structure or of a previously suggested Yb2O3 phase transformation to hexagonal phase prior to melting.« less

  16. Indirect Production of No Carrier Added (NCA) (177)Lu from Irradiation of Enriched (176)Yb: Options for Ytterbium/Lutetium Separation.

    PubMed

    Dash, Ashutosh; Chakravarty, Rubel; Knapp, Furn F Russ; Pillai, Ambikalmajan M R

    2015-01-01

    This article presents a concise review of the production of no-carrier-added (NCA) (177)Lu by the 'indirect' route by irradiating ytterbium-176 ((176)Yb)-enriched targets. The success of this production method depends on the ability to separate the microscopic amounts of NCA (177)Lu from bulk irradiated ytterbium targets. The presence of Yb(+3) from the target in the final processed (177)Lu will adversely affect the quality of (177)Lu by decreasing the specific activity and competing with Lu(+3) complexation since ytterbium will follow the same coordination chemistry. Ytterbium and lutetium are adjacent members of the lanthanide family with very similar chemical properties which makes the separation of one from the other a challenging task. This review provides a summary of the methods developed for the separation and purification of NCA (177)Lu from neutron irradiated (176)Yb-enriched targets, a critical assessment of recent developments and a discussion of the current status of this (177)Lu production method.

  17. Magnetic order and magnetoelectric properties of R2CoMn O6 perovskites (R =Ho , Tm, Yb, and Lu)

    NASA Astrophysics Data System (ADS)

    Blasco, J.; García-Muñoz, J. L.; García, J.; Subías, G.; Stankiewicz, J.; Rodríguez-Velamazán, J. A.; Ritter, C.

    2017-07-01

    We present a detailed study on the magnetic structure and magnetoelectric properties of several double perovskites R2CoMn O6 (R =Ho , Tm, Yb, and Lu). All of these samples show an almost perfect (˜94 %) ordering of C o2 + and M n4 + cations in the unit cell. Our research reveals that the magnetic ground state strongly depends on the R size. For samples with larger R (Ho and Tm), the ground state is formed by a ferromagnetic order (F type) of C o2 + and M n4 + moments, while R either remains mainly disordered (Ho) or is coupled antiferromagnetically (Tm) to the Co/Mn sublattice. For samples with smaller R (Yb or Lu), competitive interactions lead to the formation of an E -type arrangement for the C o2 + and M n4 + moments with a large amount of extended defects such as stacking faults. The Y b3 + is partly ordered at very low temperature. The latter samples undergo a metamagnetic transition from the E into the F type, which is coupled to a negative magnetodielectric effect. Actually, the real part of dielectric permittivity shows an anomaly at the magnetic transition for the samples exhibiting an E -type order. This anomaly is absent in samples with F -type order, and, accordingly, it vanishes coupled to the metamagnetic transition for R =Yb or Lu samples. At room temperature, the huge values of the dielectric constant reveal the presence of Maxwell-Wagner depletion layers. Pyroelectric measurements reveal a high polarization at low temperature, but the onset of pyroelectric current is neither correlated to the kind of magnetic ordering nor to the magnetic transition. Our study identified the pyroelectric current as thermally stimulated depolarization current and electric-field polarization curves show a linear behavior at low temperature. Therefore, no clear ferroelectric transition occurs in these compounds.

  18. Infrared-to-Visible Light Conversion in Er(3+) -Yb(3+) :Lu3 Ga5 O12 Nanogarnets.

    PubMed

    Rathaiah, Mamilla; Haritha, Pamuluri; Linganna, Kadathala; Monteseguro, Virginia; Martín, Inocencio Rafael; Lozano-Gorrín, Antonio Diego; Babu, Palamandala; Jayasankar, Chalicheemalapalli Kulala; Lavín, Victor; Venkatramu, Vemula

    2015-12-21

    Er(3+) -Yb(3+) co-doped Lu3 Ga5 O12 nanogarnets were prepared and characterized; their structural and luminescence properties were determined as a function of the Yb(3+) concentration. The morphology of the nanogarnets was studied by HRTEM. Under 488 nm excitation, the nanogarnets emit green, red, and near-infrared light. The decay curves for the ((4) S3/2 , (2) H11/2 ) and (4) F9/2 levels of the Er(3+) ions exhibit a non-exponential nature under resonant laser excitation and their effective lifetimes are found to decrease with an increase in the Yb(3+) concentration from 1.0 to 10.0 mol %. The non-exponential decay curves are well fitted to the Inokuti-Hirayama model for S=8, indicating that the mechanism of interaction for energy transfer between the optically active ions is of dipole-quadrupole type. Upon 976 nm laser excitation, an intense green upconverted emission is clearly observed by the naked eyes. A significant enhancement of the red-to-green intensity ratio of Er(3+) ions was observed with an increase in Yb(3+) concentration. The power dependence and the dynamics of the upconverted emission confirm the existence of two-photon upconversion processes for the green and red emissions. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  19. Pressure-induced zircon-type to scheelite-type phase transitions in YbPO{sub 4} and LuPO{sub 4}

    SciTech Connect

    Zhang, F.X. Lang, M.; Ewing, R.C. Lian, J.; Wang, Z.W.; Hu, J.; Boatner, L.A.

    2008-10-15

    The tetragonal orthophosphates, YbPO{sub 4} and LuPO{sub 4}, were studied by in situ X-ray diffraction (XRD) at pressures up to 52 and 43 GPa, respectively. A reversible phase transition from the zircon structure-type to the scheelite structure-type was found at {approx}22 GPa for YbPO{sub 4} and 19 GPa for LuPO{sub 4}. Coinciding with the transition from the zircon structure-type to the scheelite structure-type, there is a {approx}10% reduction in volume and a significant increase in the bulk modulus for both compounds. - Graphical abstract: The tetragonal orthophosphates, YbPO{sub 4} and LuPO{sub 4}, show reversible phase transitions from the zircon structure-type to the scheelite structure-type at {approx}22 and 19 Gpa, respectively. Coinciding with the phase transition, there is a {approx}10% reduction in unit cell volume.

  20. Optical properties of NaLuF4: Yb3+: Tm3+/Ho3+ rare earth nanocrystals in microstructure hollow fiber

    NASA Astrophysics Data System (ADS)

    Zhang, Yundong; Li, Hui; Li, Hanyang; Wu, Yongfeng; Yu, Changqiu; Zhang, Tuo; Yuan, Ping

    2016-11-01

    In the present paper, we first demonstrate NaLuF4: Yb3+: Tm3+/Ho3+ rare earth nanocrystals in microstructure hollow fiber. An analysis of the intense blue upconversion emission at 450 and 475 nm in Tm3+/Yb3+ codoped NaLuF4 under excitation power 0.65W available from solid laser emitting at 980nm, has been undertaken. Fluorescence intensity ratio (FIR) variation of temperature-sensitive blue upconversion emission at 450and 475 nm in this material was recorded in the temperature range from 300 to 345 K. The maximum sensitivity derived from the FIR technique of the blue upconversion emission is approximately 0.005 K-1. The results imply that Tm3+/Yb3+ codoped NaLuF4 is a potential candidate for the optical temperature sensor.

  1. Fabrication of a novel nanocomposite Ag/graphene@SiO2-NaLuF4:Yb,Gd,Er for large enhancement upconversion luminescence.

    PubMed

    Yin, Dongguang; Cao, Xianzhang; Zhang, Lu; Tang, Jingxiu; Huang, Wenfeng; Han, Yanlin; Wu, Minghong

    2015-06-28

    Upconversion nanocrystals have a lot of advantages over other fluorescent materials. However, their applications are still limited due to their comparatively low upconversion luminescence (UCL). In the present study, a novel nanocomposite of Ag/graphene@SiO2-NaLuF4:Yb,Gd,Er for enhancing UCL was fabricated successfully, and its morphology, crystalline phase, composition, and fluorescent property were investigated. It is interesting to find that the Ag/graphene@SiO2-NaLuF4:Yb,Gd,Er and Ag@SiO2-NaLuF4:Yb,Gd,Er nanocomposites showed high UCL enhancements of 52- and 10-fold compared to the control of Ag-free nanocomposite SiO2-NaLuF4:Yb,Gd,Er, respectively. The enhancement of 52-fold is greater than those reported in our previous studies and some papers. Moreover, the measured life times of the Ag-presented nanocrystals were longer than that of Ag-absent counterparts. These enhancements of UCL can be ascribed to the effect of metal-enhanced fluorescence, which is caused by the enhancement of the local electric field. The UCL intensity of Ag/graphene@SiO2-NaLuF4:Yb,Gd,Er was 5.2-fold higher than that of Ag@SiO2-NaLuF4:Yb,Gd,Er, indicating that graphene presented in the fabricated nanocomposite structure favors metal-enhanced UCL. The small-sized Ag nanoparticles anchored on the graphene sheet mutually enhanced each other's polarizability and surface plasmon resonance, resulting in a big metal-enhanced UCL. This study provides a new strategy for effectively enhancing the UCL of upconversion nanocrystals. The enhancement potentially increases the overall upconversion nanocrystal detectability for highly sensitive biological, medical, and optical detections.

  2. Gamow-Teller Strengths of the Inverse Beta Transition 176Yb-->176Lu for Spectroscopy of Proton-Proton and Other Sub-MeV Solar Neutrinos

    NASA Astrophysics Data System (ADS)

    Fujiwara, M.; Akimune, H.; van den Berg, A. M.; Cribier, M.; Daito, I.; Ejiri, H.; Fujimura, H.; Fujita, Y.; Goodman, C. D.; Hara, K.; Harakeh, M. N.; Ihara, F.; Ishikawa, T.; Jänecke, J.; Kawabata, T.; Raghavan, R. S.; Schwarz, K.; Tanaka, M.; Yamanaka, T.; Yosoi, M.; Zegers, R. G.

    2000-11-01

    Discrete Gamow-Teller (GT) transitions 176Yb-->176Lu at low excitation energies have been measured via the ( 3He,t) reaction at 450 MeV and at 0°. For 176Yb, two low-lying states are observed, setting low thresholds Q\\(ν\\) = 301 and 445 keV for neutrino ( ν) capture. Capture rates estimated from the measured GT strengths, the simple two-state excitation structure, and the low Q\\(ν\\) in Yb-Lu indicate that Yb-based ν detectors are well suited for a direct measurement of the sub-MeV solar electron-neutrino ( νe) spectrum including pp neutrinos.

  3. Crystal growth and spectroscopic properties of Yb:CaYAlO 4 single crystal

    NASA Astrophysics Data System (ADS)

    Li, Dongzhen; Xu, Xiaodong; Cheng, Yan; Cheng, Shishu; Zhou, Dahua; Wu, Feng; Xia, Changtai; Xu, Jun; Zhang, Jian

    2010-07-01

    A Yb 3+-doped CaYAlO 4 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:CaYAlO 4 have been evidenced to be similar to those in undoped CaYAlO 4. The polarized absorption spectra and the fluorescence spectrum of the Yb:CaYAlO 4 crystal were measured at room temperature. The fluorescence decay time of the Yb 3+ ion was investigated. The results show that Yb:CaYAlO 4 has potential as a laser gain medium for an ultrashort laser system.

  4. Pressure-Induced Zircon-Type to Scheelite-Type Phase Transition in Orthophosphates YbPO4 and LuPO4

    SciTech Connect

    Zhang, F.; Maik, L; Ewing, R; Lian, J; Wang, Z; Hu, J; Boatner, L

    2008-01-01

    The tetragonal orthophosphates, YbPO4 and LuPO4, were studied by in situ X-ray diffraction (XRD) at pressures up to 52 and 43 GPa, respectively. A reversible phase transition from the zircon structure-type to the scheelite structure-type was found at not, vert, similar22 GPa for YbPO4 and 19 GPa for LuPO4. Coinciding with the transition from the zircon structure-type to the scheelite structure-type, there is a not, vert, similar 10% reduction in volume and a significant increase in the bulk modulus for both compounds.

  5. Intermediate valence in single crystals of (Lu{sub 1−x}Y b{sub x}){sub 3}Rh{sub 4}Ge{sub 13} (0 ≤ x ≤ 1)

    SciTech Connect

    Rai, Binod K.; Morosan, E.

    2015-04-01

    Single crystals of (Lu{sub 1−x}Y b{sub x}){sub 3}Rh{sub 4}Ge{sub 13} were characterized by magnetization, specific heat, and electrical resistivity measurements. Doping Yb into the non-magnetic Lu{sub 3}Rh{sub 4}Ge{sub 13} compound tunes this cubic system’s properties from a superconductor with disordered metal normal state (x < 0.05) to a Kondo for 0.05 ≤ x ≤0.2 and intermediate valence at the highest Yb concentrations. The evidence for intermediate Yb valence comes from a broad maximum in the magnetic susceptibility and X-ray photoelectron spectroscopy. Furthermore, the resistivity displays a local maximum at finite temperatures at intermediate compositions x, followed by apparent metallic behavior closest to the Yb end compound in the series.

  6. Structural and thermoelectric properties of BaRCo{sub 4}O{sub 7} (R = Dy, Ho, Er, Tm, Yb, and Lu)

    SciTech Connect

    Wong-Ng, W.; Yan, Y.; Liu, G.; Xie, W.; Tritt, T.; Kaduk, J.; Thomas, E.

    2011-12-01

    The structure and thermoelectric properties of a series of barium lanthanide cobaltites, BaRCo{sub 4}O{sub 7} (R = Dy, Ho, Er, Tm, Yb, and Lu), which were prepared using the spark plasma synthesis technique, have been investigated. The space group of these compounds was re-determined and confirmed to be P31c instead of the reported P6{sub 3}mc. The lattice parameters a and c range from 6.26279(2) Angst to 6.31181(6) Angst , and from 10.22468(6) Angst to 10.24446(15) Angst for R = Lu to Dy, respectively. The crystal structure of BaRCo{sub 4}O{sub 7} is built up from Kagome sheets of CoO{sub 4} tetrahedra, linked by triangular layers of CoO{sub 4} tetrahedra. The values of figure of merit (ZT) of the BaRCo{sub 4}O{sub 7} samples were determined to be around 0.02 at 800 K. X-ray diffraction patterns of these samples have been determined and submitted to the Powder Diffraction File.

  7. Crystal growth and scintillation properties of Lu substituted CeBr3 single crystals

    NASA Astrophysics Data System (ADS)

    Ito, Tomoki; Yokota, Yuui; Kurosawa, Shunsuke; Král, Robert; Kamada, Kei; Pejchal, Jan; Ohashi, Yuji; Yoshikawa, Akira

    2016-10-01

    We grew Lu-substituted CeBr3 [(Ce1-xLux)Br3] crystals by a modified micro-pulling-down method to increase the effective atomic number and to investigate effects of the Lu substitution on the crystal growth, phase generation, chemical composition, and optical and scintillation properties. The (Ce1-xLux)Br3 crystals with x=0 and 0.01 had high transparency while the milky parts were generated in the crystals with x=0.05 and 0.20. By the analysis of chemical composition, the estimated Zeff increased to 47.9. On the other hand, the light yields were systematically decreased and decay times were increased with increasing Lu concentration.

  8. Synthesis of Multicolor Core/Shell NaLuF₄:Yb(3+)/Ln(3+)@CaF₂ Upconversion Nanocrystals.

    PubMed

    Li, Hui; Hao, Shuwei; Yang, Chunhui; Chen, Guanying

    2017-02-07

    The ability to synthesize high-quality hierarchical core/shell nanocrystals from an efficient host lattice is important to realize efficacious photon upconversion for applications ranging from bioimaging to solar cells. Here, we describe a strategy to fabricate multicolor core @ shell α-NaLuF₄:Yb(3+)/Ln(3+)@CaF₂ (Ln = Er, Ho, Tm) upconversion nanocrystals (UCNCs) based on the newly established host lattice of sodium lutetium fluoride (NaLuF₄). We exploited the liquid-solid-solution method to synthesize the NaLuF₄ core of pure cubic phase and the thermal decomposition approach to expitaxially grow the calcium fluoride (CaF₂) shell onto the core UCNCs, yielding cubic core/shell nanocrystals with a size of 15.6 ± 1.2 nm (the core ~9 ± 0.9 nm, the shell ~3.3 ± 0.3 nm). We showed that those core/shell UCNCs could emit activator-defined multicolor emissions up to about 772 times more efficient than the core nanocrystals due to effective suppression of surface-related quenching effects. Our results provide a new paradigm on heterogeneous core/shell structure for enhanced multicolor upconversion photoluminescence from colloidal nanocrystals.

  9. Influence of precipitant solution pH on the structural, morphological and upconversion luminescent properties of Lu 2O 3:2%Yb, 0.2%Tm nanopowders

    NASA Astrophysics Data System (ADS)

    Li, Li; Xiaochun, Wang; xiantao, Wei; Yonghu, Chen; Changxin, Guo; Min, Yin

    2011-02-01

    Lutetium oxide nanopowders codoped with Tm 3+ and Yb 3+ were synthesized by the reverse-strike co-precipitation method. Effects of precipitant solution pH on the structural, morphological and upconversion luminescent properties of Lu 2O 3:2%Yb, 0.2%Tm nanopowders had been investigated. The results show that pH value of the precipitant (NH 4HCO 3) solution has a significant effect on the particle size, morphology and upconversion emission intensity of the Lu 2O 3:2%Yb, 0.2%Tm nanopowders. All the samples obtained from different pH value of precipitant solution can be readily indexed to pure cubic phase of Lu 2O 3, indicating good crystallinity. The upconversion emission intensity of Lu 2O 3:2%Yb, 0.2%Tm nanopowders obtained from the precipitant solution with pH=11 is the strongest. The enhancement of the upconversion luminescence is suggested to be the consequence of reducing the number of OH - groups and the enlarged nanopowder size. The strong blue, weak red and near infrared emissions from the prepared nanopowders were observed under 980 nm laser excitation, and attributed to the 1G 4→ 3H 6, 1G 4→ 3F 4 and 3H 4→ 3H 6 transitions of Tm 3+ ion, respectively.

  10. Optical spectroscopy of Yb(3)Al(5)O(12) single crystal.

    PubMed

    Xu, Xiaodong; Zhao, Zhiwei; Song, Pingxin; Jiang, Benxue; Zhou, Guoqing; Xu, Jun; Deng, Peizhen

    2005-11-01

    Yb(3)Al(5)O(12) single crystal has been grown by Czochralski (CZ) method. The absorption spectrum was investigated at low temperature and the electronic energy levels for (2)F(5/2) multiplet of Yb(3+) in YbAG was proposed. The up-conversion emission of the crystal under 940 nm diode pumping and the X-ray excited luminescence (XEL) features of the crystal were also studied.

  11. Spectroscopic properties and laser operation of Yb3+ : SGYB crystal

    NASA Astrophysics Data System (ADS)

    Xia, Houping; Ma, Qian; Xu, Qiang; Zhao, Lei

    2017-03-01

    A Sr3Yb0.1Gd0.2Y0.7) single crystal was grown by the Czochralski method. The crystal was evaluated by absorption, emission, and luminescence decay measurements. The relevant absorption and emission cross-sections as well as fluorescence lifetimes were calculated and compared. Studies showed that the existence of Gd3+ can lead to greater structural disorder and broaden the spectra of the crystal. Diode-pumped laser action of this crystal is demonstrated for the first time, and the best output power of 1.8 W with a slope efficiency of 75.8% was obtained. Dual-wavelength and three-wavelength oscillations were observed. Thus, this crystal is suitable for use as tunable or ultrashort laser mediums.

  12. Yb-doped LiGd1-xLux(WO4)2 single crystal fibers grown from the melt and optical characterization

    NASA Astrophysics Data System (ADS)

    Rekik, B.; Derbal, M.; Benamara, O.; Lebbou, K.

    2014-11-01

    As a function of lutetium concentration, Yb(1 at%)-doped LiGd1-xLux(WO4)2 phases have been synthesized by solid state reaction. For x≤0.025, a limited solid solution corresponding to the substitution of Gd3+ by Lu3+ in LiGd(WO4)2 compound was observed. In another hand, for x≥0.8 a limited solid solution corresponding to the substitution of Lu3+ by Gd3+ in LiLu(WO4)2 was obtained. Different single crystalline fibers belonging to the Yb (1 at%)-doped LiGd1-xLux(WO4)2 system with diameter average 600 μm and length up to 30 mm have been grown by micro-pulling down method. In the stationary stable growth regime, the crystallization interface was flat and meniscus length reaches 120 μm±20. An overheating of the melt causes a strong Li2O loss and composition change in the equilibrium diagram allowing growth instabilities and crystal disconnection from the molten zone. The optical characterizations have been performed. Decay time has been recorded for the 1 at% Yb3+ doped fibers.

  13. 42  W femtosecond Yb:Lu2O3 regenerative amplifier.

    PubMed

    Caracciolo, E; Pirzio, F; Kemnitzer, M; Gorjan, M; Guandalini, A; Kienle, F; Agnesi, A; Aus Der Au, J

    2016-08-01

    We report on a femtosecond high-power regenerative amplifier based on Yb:Lu2O3. Exploiting the excellent thermo-mechanical properties of this material, we were able to achieve up to 64.5 W in continuous-wave regime, limited only by the available pump power. In pulsed operation, 42 W of average output power at a repetition rate of 500 kHz with 780 fs long pulses could be demonstrated, resulting in a pulse peak power of ∼100  MW. The spectrum was centered at 1034 nm with an FWHM of 2.4 nm, potentially allowing for even shorter pulses. At the maximum output power the beam was nearly TEM00, with an M2 value of 1.2 in both axes.

  14. Study of 57Fe Mössbauer effect in RFe2Zn20 ( R = Lu, Yb, Gd)

    DOE PAGES

    Bud’ko, Sergey L.; Kong, Tai; Ma, Xiaoming; ...

    2015-08-04

    In this document we report measurements of 57Fe Mössbauer spectra for RFe2Zn20 (R = Lu, Yb, Gd) from ~ 4.5 K to room temperature. The obtained isomer shift values are very similar for all three compounds, their temperature dependence was analyzed within the Debye model and resulted in an estimate of the Debye temperatures of 450-500 K. The values of quadrupole splitting at room temperature change with the cubic lattice constant a in a linear fashion. For GdFe2Zn20, ferromagnetic order is seen as an appearance of a sextet in the spectra. The 57Fe site hyperfine field for T → 0more » was evaluated to be ~ 2.4 T.« less

  15. Study of 57 Fe Mössbauer effect in RFe2Zn20 ( R = Lu, Yb, Gd)

    DOE PAGES

    Bud’ko, Sergey L.; Kong, Tai; Ma, Xiaoming; ...

    2015-08-04

    In this document we report measurements of 57Fe Mössbauer spectra for RFe2Zn20 (R = Lu, Yb, Gd) from ~ 4.5 K to room temperature. The obtained isomer shift values are very similar for all three compounds, their temperature dependence was analyzed within the Debye model and resulted in an estimate of the Debye temperatures of 450-500 K. The values of quadrupole splitting at room temperature change with the cubic lattice constant a in a linear fashion. For GdFe2Zn20, ferromagnetic order is seen as an appearance of a sextet in the spectra. The 57Fe site hyperfine field for T → 0more » was evaluated to be ~ 2.4 T.« less

  16. Jahn-Teller distortion and magnetic transitions in perovskite RMnO3 ( R=Ho , Er, Tm, Yb, and Lu)

    NASA Astrophysics Data System (ADS)

    Tachibana, Makoto; Shimoyama, Tomotaka; Kawaji, Hitoshi; Atake, Tooru; Takayama-Muromachi, Eiji

    2007-04-01

    The perovskite RMnO3 ( R=Ho , Er, Tm, Yb, and Lu) were prepared under high pressure and studied with heat capacity and synchrotron x-ray powder diffraction measurements. The temperature interval between the antiferromagnetic transition and the first-order transition to the presumably E -type structure narrows with the decreasing ionic radius of R , and almost closes for R=Lu . Combined with the data for the larger rare earth R , the results show intricate relationship between the complex magnetic phase diagram and significant increase of Jahn-Teller distortion found for the smallest members of RMnO3 .

  17. A quantum chemistry investigation on the structure of lanthanide triflates Ln(OTf)3 where Ln = La, Ce, Nd, Eu, Gd, Er, Yb and Lu.

    PubMed

    Hannachi, Douniazed; Ouddai, Nadia; Chermette, Henry

    2010-04-21

    Density functional theory has been used to probe the electronic structure, coordination number, optical properties and the vibration spectra of monolanthanide trifluoromethane sulfonate Ln(OTf)(3) complexes where Ln = La, Ce, Nd, Eu, Gd, Er, Yb and Lu. The study reveals that the OTf group is bonded to Ln as a bidentate ligand. TDDFT calculations show that, for La(OTf)(3), MLTC and HOMO-LUMO transitions in the UV-vis are strongly bathochromically shifted compared to those of Lu(OTf)(3.).

  18. Crystal growth, polarized spectra, and laser performance of Yb:CaGdAlO4 crystal

    NASA Astrophysics Data System (ADS)

    Di, J. Q.; Xu, X. D.; Xia, C. T.; Zheng, L. H.; Aka, G.; Yu, H. H.; Sai, Q. L.; Guo, X. Y.; Zhu, L.

    2016-04-01

    In this paper, the crystal growth, polarized spectra, and laser performance of Yb:CaGdAlO4 crystal were reported. The segregation coefficient of Yb3+ ions was calculated to be 0.47. The cell parameters were determined to be a  =  b  =  0.3658 nm, c  =  1.1985 nm. The peak absorption cross-section was calculated to be 2.65  ×  10-20 cm2 at 979 nm and the peak stimulated emission cross-section was 2.23  ×  10-20 cm2 at 980 nm for the π polarization. The continuous-wave (CW) laser operations of uncoated Yb:CaGdAlO4 crystals with 5  ×  5  ×  3 mm3 in size were demonstrated. A maximum output power of 1.6 W at 1048 nm was obtained with a slope efficiency of 28%. The results show that Yb:CaGdAlO4 crystal is a promising laser medium.

  19. Bonding in gold-rare earth [Au2M] (M = Eu, Yb, Lu) ions. A strong covalent gold-lanthanide bond

    NASA Astrophysics Data System (ADS)

    Páez-Hernández, Dayán; Muñoz-Castro, Alvaro; Arratia-Perez, Ramiro

    2017-09-01

    The electronic structure and bonding nature of a series of intermetallic gold-lanthanide [Au2Ln] molecules, where Ln = Eu, Yb, Lu is predicted via the DFT and CASSCF/CASPT2 calculations. The 2c-2e bond model shows a good description of the intermetallic bonding which have a large covalent component with important contribution from bonding interaction between the 6s-Au and the 6s-Ln shell of orbitals.

  20. Near-infrared to visible upconversion in Tm3+ and Yb3+ codoped Lu2O3 nanocrystals synthesized by hydrothermal method.

    PubMed

    Li, Li; Zhang, Xingli; Wei, Xiantao; Wang, Guangchuan; Guo, Changxin

    2014-06-01

    Lutetium oxide nanocrystals codoped with Tm3+ and Yb3+ have been successfully synthesized via adjusting the pH values of the precursor solution in a hydrothermal method followed by a subsequent calcination process. The samples were systematically characterized by X-ray diffraction, field-emission scanning microscopy, Fourier transform infrared transmittance spectroscopy, and upconversion luminescent spectra. The experimental results show that the pH values of the precursor solution have great effects on the structural, morphological, and upconversion luminescent properties of Lu2O3:2%Yb3+, 0.2%Tm3+ nanocrystals. The as-formed lutetium oxide precursors could transform to cubic Lu2O3 with the same morphology and a slight shrinkage in size after a calcination process. The upconversion emission intensity of Lu2O3:2%Yb3+, 0.2%Tm3+ nanocrystals obtained from the precursor solution with pH = 9 is the strongest. The enhancement of the upconversion luminescence is suggested to be the consequence of reducing the number of OH- groups and the enlarged nanocrystals size. Strong blue and weak red emissions from the prepared nanocrystals were observed under 980 nm laser excitation, which were attributed to the 1G4 --> 3H6 and 1G4 --> 3F4 transitions of Tm3+ ion, respectively.

  1. Valence state change and defect centers induced by infrared femtosecond laser in Yb:YAG crystals

    SciTech Connect

    Wang, Xinshun Liu, Yang; Zhao, Panjuan; Guo, Zhongyi; Li, Yan; Qu, Shiliang

    2015-04-21

    The broad band upconversion luminescence in Yb{sup 3+}:YAG crystal has been observed in experiments under the irradiation of focused infrared femtosecond laser. The dependence of the fluorescence intensity on the pump power shows that the upconversion luminescence is due to simultaneous two-photon absorption process, which indicates that the broad emission bands at 365 and 463 nm could be assigned to the 5d → 4f transitions of Yb{sup 2+} ions and the one at 692 nm could be attributed to the electron-hole recombination process on (Yb{sup 2+}-F{sup +}) centers. The absorption spectra of the Yb:YAG crystal samples before and after femtosecond laser irradiation, and after further annealing reveal that permanent valence state change of Yb ions from Yb{sup 3+} to Yb{sup 2+} and (Yb{sup 2+}-F{sup +}) centers have been induced by infrared femtosecond laser irradiation in Yb{sup 3+}:YAG crystal.

  2. Optimization of the cooling profile to achieve crack-free Yb:S-FAP crystals

    SciTech Connect

    Fang, H; Qiu, S; Kheng, L; Schaffers, K; Tassano, J; Caird, J; Zhang, H

    2007-08-20

    Yb:S-FAP [Yb{sup 3+}:Sr{sub 5}(PO{sub 4}){sub 3}F] crystals are an important gain medium for diode-pumped laser applications. Growth of 7.0 cm diameter Yb:S-FAP crystals utilizing the Czochralski (CZ) method from SrF{sub 2}-rich melts often encounter cracks during the post growth cool down stage. To suppress cracking during cool down, a numerical simulation of the growth system was used to understand the correlation between the furnace power during cool down and the radial temperature differences within the crystal. The critical radial temperature difference, above which the crystal cracks, has been determined by benchmarking the simulation results against experimental observations. Based on this comparison, an optimal three-stage ramp-down profile was implemented and produced high quality, crack-free Yb:S-FAP crystals.

  3. Influence of other rare earth ions on the optical refrigeration efficiency in Yb:YLF crystals.

    PubMed

    Di Lieto, Alberto; Sottile, Alberto; Volpi, Azzurra; Zhang, Zhonghan; Seletskiy, Denis V; Tonelli, Mauro

    2014-11-17

    We investigated the effect of rare earth impurities on the cooling efficiency of Yb³⁺:LiYF₄ (Yb:YLF). The refrigeration performance of two single crystals, doped with 5%-at. Yb and with identical history but with different amount of contaminations, have been compared by measuring the cooling efficiency curves. Spectroscopic and elemental analyses of the samples have been carried out to identify the contaminants, to quantify their concentrations and to understand their effect on the cooling efficiencies. A model of energy transfer processes between Yb and other rare earth ions is suggested, identifying Erbium and Holmium as elements that produce a detrimental effect on the cooling performance.

  4. Crystallization-Dependent Luminescence Properties of Ce:LuPO4.

    PubMed

    Sun, Congting; Li, Xingxing; Wang, Hao; Xue, Dongfeng

    2016-03-21

    The luminescence properties of Ce:LuPO4 depend on both the Ce(3+) center and the host lattice. In this article, we studied the dependence of the luminescence properties of Ce:LuPO4 on both the doping concentration of Ce(3+) and the size and morphology of the LuPO4 matrix at micro- and nanosize regimes. The crystalline behavior of Ce:LuPO4, including its size and shape, was investigated via precursor transformation crystallization. On the basis of this crystallization approach, Ce:LuPO4 hollow nanospheres, nanorods, and regular tetrahedrons were obtained. For micro- and nanostructured Ce:LuPO4, the surface-induced chemical bonding architecture can be effectively varied by controlling the size of the crystalline material and its geometry. Our experimental observations demonstrate that one-dimensional Ce:LuPO4 nanorods doped with 0.1 mol % Ce(3+) possess the best performance among the as-prepared samples. The significant anisotropy of Ce:LuPO4 nanorods can result in a larger specific surface area and enhanced luminescence properties. Moreover, the improved luminescence property of Ce:LuPO4 nanostructures can also be optimized by increasing the preferential anisotropic chemical bonding architecture to regulate the 5d level of Ce(3+). Our work also shows that the photoluminescence emission intensity of Ce:LuPO4 nanorods is increased as the surface area normal to their axial direction increases. From the standpoint of crystallization, the luminescence properties of Ce(3+) in nano- and microsize matrixes can be well-optimized by controlling the crystalline behavior of the host lattice under proper synthesis conditions.

  5. Synthesis and characterization of KY3F10:Yb:Nd:Tm crystals

    NASA Astrophysics Data System (ADS)

    Silva, H. M.; Courrol, L. C.; Gomes, L.; Bertram, R.; Baldochi, S. L.; Ranieri, I. M.

    2010-11-01

    Energy transfer processes that generate thulium blue and ultraviolet emissions by upconversion were studied in KY3F10:Tm (KY3F:Tm), using Nd3+ and Yb3+ as sensitizers of Tm3+. The upconversion mechanisms were determined by exciting into the Nd and Tm absorption bands with a diode laser at 797nm. It was observed that the intensity of the Tm3+ blue and ultraviolet emissions in 484, 453, 366 and 350 nm were very dependent of the Yb3+ concentration in the samples, confirming that the main energy transfer processes involve Nd3+ and Yb3+ ions. KY3F10:Nd (1.3 mol%):Tm (0.5 mol%) crystals codoped with 5, 10, 20 and 30 mol% Yb were prepared by slow cooling from the melt, to establish the optimal Yb concentration that maximizes the Nd3+→Yb3+→Tm3+ energy transfer.

  6. Comparison of LuAP and LuYAP crystal properties from statistically significant batches produced with two different growth methods

    NASA Astrophysics Data System (ADS)

    Trummer, J.; Auffray, E.; Lecoq, P.; Petrosyan, A.; Sempere-Roldan, P.

    2005-10-01

    Measurements of the light yield, decay time and transmission were carried out on LuAP:Ce and mixed LuYAP:Ce crystals, which are new scintillation materials considered for Positron Emission Tomography (PET) and are used in the ClearPET™ [Auffray et al., Nucl. Sci. Methods A 527 (2004) 171 [15

  7. Flux growth of MBO3 (M=Fe, Ga, In, Sc, Lu) single crystals

    NASA Astrophysics Data System (ADS)

    Ovchinnikov, S. G.; Rudenko, V. V.

    2016-12-01

    The temperatures for saturation of the MBO3 (M=Fe, Ga, In, Sc, Lu) compounds in the M2O3-B2O3- (70 PbO-30 PbF2, wt%) solvents are determined. The growth rates of FeBO3 and GaBO3 crystal faces as functions of the flux supercooling are obtained. It is demonstrated that the bulk FeBO3 and GaBO3 crystals can be grown in a narrow flux supercooling range using a controlled seeding technique. The MBO3 (M=In, Sc, Lu) crystals in the form of (111) plates are synthesized by spontaneous crystallization.

  8. New Yb-doped crystals for high-power and ultrashort lasers

    NASA Astrophysics Data System (ADS)

    Druon, F.; Boudeile, J.; Zaouter, Y.; Hanna, M.; Balembois, F.; Georges, P.; Petit, J.; Goldner, P.; Viana, B.

    2006-09-01

    Since the beginning of the 90's, Titanium Sapphire has become the crystal of choice for the development of ultrashort laser system producing very short and powerful pulses using the Chirped Pulse Amplification technique. In parallel to these developments leading to commercial products, new laser crystals have been studied in order to reach directly other wavelength range and to overcome the need to develop cw or pulsed green laser to pump the Titanium Sapphire crystal. In order to be able to directly pump the crystals with very efficient and high power semiconductor laser, new crystals doped with ytterbium ions have been developed. Actually, in the field of femtosecond lasers, an intense interest has been shown for ytterbium-doped laser-crystals. These crystals are now well-known to be particularly suitable for very efficient, directly-diode-pumped, solid state femtosecond oscillators. However, it has been shown that the spectral properties of the Yb 3+ dopant strongly depend on the matrix host and a lot of works have been done to find the "ideal" matrix allowing both ultrashort-pulsed and high-power lasers. Firstly, in order to take advantage of the very high-power laser diodes available to pump Yb-doped materials, ideal crystals need to be able to hold high power pumping; so high thermal conductivity is required (>5W/m/K, typically). Secondly, to generate very short pulses (<100 fs) ideal crystals have to demonstrate very broad and smooth spectra. Among the numerous Yb-doped crystals already studied, many failed with one of these two contradictory criteria (contradictory because broad spectra are often synonymous of high disorder in the host lattice and the good thermal conductivity requires an ordered matrix to allow good propagation of phonons). In this paper, we are relating the performance of a new Yb-doped crystal: Yb:CaGdAlO4 (Yb:CALGO) and how it takes place in this quest of "ideal" crystal. Actually, this very new crystal allowed, to our best knowledge

  9. Enhancement of Tb-Yb quantum cutting emission by inverse opal photonic crystals

    NASA Astrophysics Data System (ADS)

    Wang, Qi; Qiu, Jianbei; Song, Zhiguo; Yang, Zhengwen; Yin, Zhaoyi; Zhou, Dacheng; Wang, Siqin

    2016-04-01

    Yb3+, Tb3+ co-doped YPO4 inverse opal photonic crystal was prepared directly by sol-gel technique in combination with self-assembly method. With the influence of the photonic band gap, quantum cutting emission of Tb3+, Yb3+ was investigated in photonic crystals by photoluminescence and fluorescence lifetime. The result clearly shows that, when the spontaneous emission of donor Tb3+ is inhibited by photonic band gap, Tb3+-Yb3+ quantum cutting quantum efficiency from Tb3+ to Yb3+ could be enhanced from 131.2% to 140.5%. The mechanisms for the influence of the photonic band gap on quantum cutting process of Tb3+ and Yb3+ are discussed. We believe that the present work will be valuable for the foundational study of quantum cutting energy transfer process and application of quantum cutting optical devices in spectral modification materials for silicon solar cells.

  10. Energy enhancement of mixed Nd:LuYSGG crystal in passively Q-switched lasers.

    PubMed

    Wang, Baolin; Tian, Li; Yu, Haohai; Zhang, Huaijin; Wang, Jiyang

    2015-07-01

    The continuous-wave (cw) and passively Q-switched laser performances of mixed Nd:Lu(2)YSc(1.5)Ga(3.5)O(12) (Nd:LuYSGG) crystal at 1.06 μm were reported for the first time. The cw output power reached 4.39 W at the absorbed pump power of 10.34 W with slope efficiency of 48.0%. With a Cr(4+):YAG crystal as both the saturable absorber and output coupler, a passively Q-switched laser was realized with the maximum average output power of 1.43 W and slope efficiency of 21.0%. The shortest pulse width, largest pulse energy, and highest peak power were 4.1 ns, 157.1 μJ, and 38.3 kW, respectively. Compared with Nd:Lu(3)Sc(1.5)Ga(3.5)O(12) (Nd:LuSGG) crystal, the pulse energy and peak power are enhanced over more than two times for Nd:LuYSGG. The results show that Nd:LuYSGG crystal is a promising laser material with large energy storage capacities and suitable for the application of pulsed lasers with shorter pulses and larger energies.

  11. Synthesis of NaLuF4:Er3+, Yb3+, Ce3+ nanoparticles and study of photoluminescent properties in C - band

    NASA Astrophysics Data System (ADS)

    Khaydukov, K. V.; Rocheva, V. V.; Savelyev, A. G.; Sarycheva, M. E.; Asharchuk, I. M.

    2016-12-01

    The novel core@shell nanocrystals β-NaLuF4@NaLuF4 co-doped with rare-earth ions Er3+, Yb3+, Ce3+ have been synthesized. The nano-particles indicate the intensive lines of anti-Stokes luminescence in the telecommunication C - band of spectrum when pumped at 970-980 nm. The nanoparticles have been characterized by transmission electron microscopy and spectrofluorimetry. The nanoparticles have a size 40-80 nm and possess the intensive photo-luminescence 73 nm bandwidth centered around 1530 nm. The photo-luminescence kinetics of β-NaLuF4: Er3+/ Yb3+/ Ce3+ has been studied in IR range of spectrum. We have demonstrated that doping with cerium ions prevents serial stepwise excitation of erbium ions. Consequently, the lifetime of transition in erbium 4I13/2→4I15/2 has risen up to 6.9 ms. Intensity of 1530 nm line in Er3+ ions excited at 980 nm has been increased up to 6 times. Therefore, the nanoparticles are applicable to fabrication of compact waveguide amplifiers for C - band.

  12. High-throughput and microwave investigation of rare earth phosphonatoethanesulfonates-Ln(O{sub 3}P-C{sub 2}H{sub 4}-SO{sub 3}) (Ln=Ho, Er, Tm, Yb, Lu, Y)

    SciTech Connect

    Sonnauer, Andreas

    2008-11-15

    Following the strategy of using bifunctional phosphonic acids for the synthesis of new metal phosphonates, the flexible ligand 2-phosphonoethanesulfonic acid, H{sub 2}O{sub 3}P-C{sub 2}H{sub 4}-SO{sub 3}H (H{sub 3}L), was used in a high-throughput (HT) and microwave investigation of rare earth phosphonatoethanesulfonates. The HT-investigation led to six isotypic compounds Ln(O{sub 3}P-C{sub 2}H{sub 4}-SO{sub 3}) with Ln=Ho (1), Er (2), Tm (3), Yb (4), Lu (5) and Y (6). The syntheses were scaled-up in glass reactor tubes in order to obtain larger amounts for a detailed characterization. Based on these results all compounds could be also synthesized by microwave-assisted heating and the influence of reaction time and stirring rate during the synthesis was established. For compound 2 the crystal structure was determined by single-crystal X-ray diffraction. The compounds contain isolated slightly distorted LnO{sub 6} octahedra that are connected by the phosphonate and sulfonate groups into a three-dimensional framework. Thermogravimetric investigations demonstrate the high thermal stability of the compounds up to 460 deg. C. - Graphical abstract: A high-throughput and microwave investigation of the System LnX{sub 3}/H{sub 2}O{sub 3}P-C{sub 2}H{sub 4}-SO{sub 3}/NaOH/H{sub 2}O led to six new compounds Ln(O{sub 3}P-C{sub 2}H{sub 4}-SO{sub 3}) with Ln=Ho, Er, Tm, Yb, Lu, Y.

  13. Spectroscopic and laser characterization of Yb,Tm:KLu(WO4)2 crystal

    NASA Astrophysics Data System (ADS)

    Loiko, P. A.; Serres, J. M.; Mateos, X.; Demesh, M. P.; Yasukevich, A. S.; Yumashev, K. V.; Petrov, V.; Griebner, U.; Aguiló, M.; Díaz, F.

    2016-01-01

    We report on a comprehensive spectroscopic and laser characterization of monoclinic Yb,Tm:KLu(WO4)2 crystals. Stimulated-emission cross-section spectra corresponding to the 3F4 → 3H6 transition of Tm3+ ions are determined. The radiative lifetime of the 3F4 state of Tm3+ ions is 0.82 ms. The maximum Yb3+ → Tm3+ energy transfer efficiency is 83.9% for 5 at.% Yb - 8 at.% Tm doping. The fractional heat loading for Yb,Tm:KLu(WO4)2 is 0.45 ± 0.05. Using a hemispherical cavity and 5 at.% Yb - 6 at.% Tm doped crystal, a maximum CW power of 227 mW is achieved at 1.983-2.011 μm with a maximum slope efficiency η = 14%. In the microchip laser set-up, the highest slope efficiency is 20% for a 5 at.% Yb- 8 at.% Tm doped crystal with a maximum output power of 201 mW at 1.99-2.007 μm. Operation of Yb,Tm:KLu(WO4)2 as a vibronic laser emitting at 2.081-2.093 μm is also demonstrated.

  14. Synthesis of a New Cubic Conductive Cu6O8-yMX (M=Tb, Dy, Ho, Er, Tm, Yb, Lu, X=NO3, Cl) Family

    NASA Astrophysics Data System (ADS)

    Sugise, Ryoji; Ohdan, Kyoji; Hamamoto, Toshikazu; Kashiwagi, Kouichi; Shirai, Masashi; Yazawa, Ichiro; Ihara, Hideo

    1993-07-01

    A new cubic Cu6O8-yMX family (M=Tb, Dy, Ho, Er, Tm, Yb, Lu, X=NO3, Cl) was prepared. These compounds showed metallic resistivity and paramagnetism. The Cu6O8-yMX compounds could be easily synthesized when a trivalent metal element (M) whose oxide (M2O3) has a cubic Tl2O3-type structure was used. These compounds were prepared in the thermal decomposition process of a mixed copper nitrate, copper chloride and metal element oxide solution. The lattice constants of the Cu6O8-yMX compounds were related to those of M2O3.

  15. Energy transfer rates of KY3F10:Yb:Nd:Tm crystals

    NASA Astrophysics Data System (ADS)

    Courrol, L. C.; Linhares, H. M. S. M. D.; Librantz, A. F. H.; Baldochi, S. L.; Gomes, L.; Ranieri, I. M.

    2010-11-01

    In this work we present the spectroscopic properties of KY3F10 (KY3F) single crystals doped with thulium and also co-doped with ytterbium and/or neodymium, KY3F:Yb:Nd:Tm and KY3F:Nd:Tm. The most important processes that lead to the thulium up conversion emissions were identified. The absorption spectra of the samples were measured at room temperature in the range of 200 nm-1200 nm. The emission spectra were obtained by exciting the samples with a 797 nm laser diode and were analyzed using a lock-in amplifier technique. A time-resolved luminescence spectroscopy technique was employed to measure the luminescence decays and to determine the mechanisms involved in the energy transfer up-conversion processes. Analysis of the energy transfer processes dynamics in KY3F:Yb:Tm:Nd crystal, using selective pulsed-laser excitations, shows that the energy transfer from Nd3+ to Yb3+ ions is the mechanism responsible for the enhancement of the blue up-conversion efficiency when compared with the Yb:Tm system. In the case of KY3F:Nd:Tm it is observed emissions at 350, 355 and 452 nm excited by an additional Yb:Tm step cross relaxation, Yb (2F5/2) : Tm (1G4) that populates the 1D2 (Tm3+) excited level. A study of the energy transfer processes in KY3F:Yb:Tm:Nd crystal showed that the 1G4 excited level is mainly populated by the sequence of two nonradiative energy processes that starts well after the Nd3+ and Tm3+ excitation at 797nm: Nd (4F3/2) → Yb (2F7/2) followed by Yb (2F5/2) → Tm (3H4) → Tm (1G4).

  16. Up-conversion in YLF:Yb3+,Tm3+ laser crystals

    NASA Astrophysics Data System (ADS)

    Tkachuk, Alexandra M.; Razumova, Irene K.; Joubert, Maria-France; Moncorge, Richard

    1998-12-01

    We have studied the Yb3+ (reversible reaction) Tm3+ nonradiative energy transfer processes responsible for population of the 1G4 thulium level under Yb3+ or Tm3+ selective laser excitation of YLF:Tm3+,Yb3+ crystal. The microparameters and the rates of the energy transfer via cross-relaxation schemes are determined. It is concluded that the process of populating the 1G4 thulium level is greatly affected by up-conversion processes not only from the 3H4 but also from the 3F4 level, proceeding within the static decay model.

  17. Method for preparing high specific activity 177Lu

    DOEpatents

    Mirzadeh, Saed; Du, Miting; Beets, Arnold L.; Knapp, Jr., Furn F.

    2004-04-06

    A method of separating lutetium from a solution containing Lu and Yb, particularly reactor-produced .sup.177 Lu and .sup.177 Yb, includes the steps of: providing a chromatographic separation apparatus containing LN resin; loading the apparatus with a solution containing Lu and Yb; and eluting the apparatus to chromatographically separate the Lu and the Yb in order to produce high-specific-activity .sup.177 Yb.

  18. Experimental study on all Yb-doped photonic crystal fiber laser

    NASA Astrophysics Data System (ADS)

    Fu, Jian; Hou, Zhiyun; Zhou, Guiyao; Zhao, Jingde; Zhang, Wei; Xia, Changming; Cang, Xuelong; Liu, Jiantao

    2017-02-01

    In this paper, we demonstrated an experiment of the all Yb-doped photonic crystal fiber laser using free space optical paths method. The experimental setup of all Yb-doped photonic crystal fiber laser is composed of the seed laser and the amplifier. The laser gain medium of the seed laser and the amplifier are the same Yb-doped photonic crystal fibers that are fabricated by non-chemical vapor deposition (Non-CVD) technology. The seed laser cavity is a Fabry-Perot cavity. The amplifier is pumped by back-end method. They are coupled each other by lens and dichroic mirrors on the optical table. The experimental results have a good reference value for the photonic crystal fiber laser research in the future.

  19. Large-scale synthesis of Lu{sub 2}O{sub 3}:Ln{sup 3+} (Ln{sup 3+} = Eu{sup 3+}, Tb{sup 3+}, Yb{sup 3+}/Er{sup 3+}, Yb{sup 3+}/Tm{sup 3+}, and Yb{sup 3+}/Ho{sup 3+}) microspheres and their photoluminescence properties

    SciTech Connect

    Gao, Yu; Gong, Jian; Fan, Miaomiao; Fang, Qinghong; Wang, Na; Han, Wenchi; Xu, Zhenhe

    2012-12-15

    Graphical abstract: In this work, multicolor and monodisperse Lu{sub 2}O{sub 3}:Ln{sup 3+} (Ln{sup 3+} = Eu{sup 3+}, Tb{sup 3+}, Yb{sup 3+}/Er{sup 3+}, Yb{sup 3+}/Tm{sup 3+}, and Yb{sup 3+}/Ho{sup 3+}) microspheres were prepared by a homogeneous precipitation method followed by a subsequent calcination process. Display Omitted Highlights: ► Lu{sub 2}O{sub 3}:Ln{sup 3+} microspheres were prepared by a precipitation followed by a calcination process. ► Lu{sub 2}O{sub 3}:Eu{sup 3+}/Tb{sup 3+} samples exhibit respective red or green emissions. ► Lu{sub 2}O{sub 3}:Yb{sup 3+}/Er{sup 3+}/Tm{sup 3+}/Ho{sup 3+} exhibit emissions of green, blue, yellow-green, respectively. ► These finding may find potential applications in bioanalysis and field emission displays. -- Abstract: In this work, multicolor and monodisperse Lu{sub 2}O{sub 3}:Ln{sup 3+} (Ln{sup 3+} = Eu{sup 3+}, Tb{sup 3+}, Yb{sup 3+}/Er{sup 3+}, Yb{sup 3+}/Tm{sup 3+}, and Yb{sup 3+}/Ho{sup 3+}) microspheres were prepared by a homogeneous precipitation method followed by a subsequent calcination process. X-ray diffraction (XRD), Fourier transformed infrared (FT-IR), thermogravimetric analysis (TGA), scanning electron microscopy (SEM), transmission electron microscopy (TEM), photoluminescence (PL) spectra, and cathodoluminescence (CL) spectra were employed to characterize the samples. Upon ultraviolet and low-voltage electron beams excitation, Lu{sub 2}O{sub 3}:Ln{sup 3+} (Ln{sup 3+} = Eu{sup 3+} and Tb{sup 3+}) samples exhibit respective bright red (Eu{sup 3+}, {sup 5}D{sub 0} → {sup 7}F{sub 2}) and green (Tb{sup 3+}, {sup 5}D{sub 4} → {sup 7}F{sub 5}) down-conversion (DC) emissions. Under 980 nm NIR irradiation, Lu{sub 2}O{sub 3}:Ln{sup 3+} (Ln{sup 3+} = Yb{sup 3+}/Er{sup 3+}, Yb{sup 3+}/Tm{sup 3+}, and Yb{sup 3+}/Ho{sup 3+}) exhibit characteristic up-conversion (UC) emissions of green (Er{sup 3+}, {sup 4}S{sub 3/2}, {sup 2}H{sub 11/2} → {sup 4}I{sub 15/2}), blue (Tm{sup 3+}, {sup 1}G{sub 4} → {sup

  20. Tb3+-Yb3+ cooperative down and up conversion processes in Tb0.81Ca0.19F2.81:Yb3+ single crystals

    NASA Astrophysics Data System (ADS)

    Molina, P.; Vasyliev, V.; Víllora, E. G.; Shimamura, K.

    2011-12-01

    The energy transfer processes between Tb3+ and Yb3+ ions are studied in Tb-based fluoride single crystals. These are very transparent from the UV to the IR wavelength regions, except for the characteristic absorption lines of the rare-earth ions under study. In contrast with previously reported Tb3+-doped glasses and oxide powders, these crystals containing a high Tb3+ concentration present two major advantages for the study of the energy transfer processes in the Tb3+-Yb3+ ion pair. Firstly, the adverse influence of host defects is minimized with the use of high quality crystals. Secondly, the high Tb3+ concentration guarantees a much higher absorption cross-section of UV light, and consequently these crystals have real potential for practical applications. Photoluminescence spectra in the visible-IR wavelength region demonstrate the existence of efficient down and up conversion processes by crossed excitation and emission characteristics of Tb3+ and Yb3+ ions. In the down conversion process, Tb3+(5D4) → 2Yb3+(2F5/2), two IR photons are emitted for each Tb3+ ion deexcited by second-order energy transfer to two Yb3+ ions. The total quantum efficiency of the down conversion process in the fluoride system is shown to increase linearly with the Yb3+ concentration, reaching its maximum at the Yb3+ solubility limit in the fluoride host. Further, efficient up conversion by two- and three-IR photon absorption is observed.

  1. [Study on Spectral Characteristics of Two Kinds of Home-Made Novel Yb-Doped Fluoride Laser Crystals].

    PubMed

    Xu, Wen-bin; Chai, Lu; Shi, Jun-kai; Song, You-jian; Hu, Ming-lie; Wang, Qing-yue; Su, Liang-bi; Jiang, Da-peng; Xu, Jun

    2015-09-01

    Yb-doped fluoride crystals are of important another Yb-doped laser materials besides Yb-doped oxide, which are becoming one of interests for developing tunable lasers and ultrafast lasers. In this paper, the systematic and contrastive experiments of the optical spectral characteristics are presented for two types of home-made novel Yb-doped fluoride laser crystals, namely, Yb-doped CaF2-SrF2 mixed crystal and co-doped Yb, Y:CaF2 single crystal. The fluorescent features of Yb-doped CaF2-SrF2 mixed crystal and co-doped Yb, Y:CaF2 single crystal are apparently different by the fluorescence experiment. The physical mechanism of these fluorescence spectra were analyzed and proposed. The influence of doping concentrations of active Yb(3+) ions or co-doping Y ions on the absorption of Yb-doped CaF2-SrF2 mixed crystal and co-doped Yb, Y:CaF2 single crystal was experimentally investigated, and the optimal values of doping concentrations of active Yb(3+) ions or co-doping Y ions in the two types of fluoride laser crystals were obtained. Continuous-wave laser operation for the two novel fluoride laser crystals has been achieved in three-mirror-folded resonator using a laser diode as the pump source. Therein, the laser operation for the co-doped Yb, Y:CaF2 crystal is demonstrated for the first time. For the two types of fluoride laser crystals (four samples), the input-output power relational curves, the optical slope efficiencies and the laser spectra were demonstrated by the laser experiments. By comparisons between the two types of fluoride laser crystals in the absorbability, fluorescence and laser spectra, laser threshold and slope efficiency of the continuous-wave laser operation, the results show that the best one of the four samples in spectral and laser characteristics is co-doped 3at%Yb, 6at% Y:CaF2 single crystal, which has an expected potential in the application. The research results provide available references for improving further laser performance of Yb

  2. PEGylated NaLuF4: Yb/Er upconversion nanophosphors for in vivo synergistic fluorescence/X-ray bioimaging and long-lasting, real-time tracking.

    PubMed

    Yi, Zhigao; Lu, Wei; Xu, Yaru; Yang, Jing; Deng, Li; Qian, Chao; Zeng, Tianmei; Wang, Haibo; Rao, Ling; Liu, Hongrong; Zeng, Songjun

    2014-12-01

    Simultaneous in vivo luminescence and X-ray bioimaging in a tissue or animal integrates the advantages of each single-modal imaging technology, and will find widespread application in biological and clinical fields. However, synergistic dual-modal bioimaging that utilizes a new generation of upconversion nanoprobes is still limited. In addition, investigations concentrated on in vivo biodistribution of these nanoprobes may contribute to diagnosis and treatment, but long-term in vivo tracking based on these nanoprobes is rarely reported. In this work, water-soluble NaLuF4: Yb/Er nanophosphors were prepared through modified one-pot simultaneous synthesis and surface modification method. Owing to the outstanding upconverting emissions and large X-ray absorption coefficient/K-edge value of Lu and doped Yb ions, the obtained nanoprobes were successfully used as luminescent nanoprobes and X-ray contrast agents for in vivo synergistic upconversion luminescence and X-ray bioimaging. The in vivo biodistribution of these nanoprobes were observed, and the results based on long-term tracking reveal that the as-prepared nanoprobes first aggregated in the lung of the mouse, transferred to the liver, and finally moved to the spleen. Copyright © 2014 Elsevier Ltd. All rights reserved.

  3. Hydrothermal synthesis of NaLuF4:153Sm,Yb,Tm nanoparticles and their application in dual-modality upconversion luminescence and SPECT bioimaging.

    PubMed

    Yang, Yang; Sun, Yun; Cao, Tianye; Peng, Juanjuan; Liu, Ying; Wu, Yongquan; Feng, Wei; Zhang, Yingjian; Li, Fuyou

    2013-01-01

    Upconversion luminescence (UCL) properties and radioactivity have been integrated into NaLuF(4):(153)Sm,Yb,Tm nanoparticles by a facile one-step hydrothermal method, making these nanoparticles potential candidates for UCL and single-photon emission computed tomography (SPECT) dual-modal bioimaging in vivo. The introduction of small amount of radioactive (153)Sm(3+) can hardly vary the upconversion luminescence properties of the nanoparticles. The as-designed nanoparticles showed very low cytotoxicity, no obvious tissue damage in 7 days, and excellent in vitro and in vivo performances in dual-modal bioimaging. By means of a combination of UCL and SPECT imaging in vivo, the distribution of the nanoparticles in living animals has been studied, and the results indicated that these particles were mainly accumulated in the liver and spleen. Therefore, the concept of (153)Sm(3+)/Yb(3+)/Tm(3+) co-doped NaLuF(4) nanoparticles for UCL and SPECT dual-modality imaging in vivo of whole-body animals may serve as a platform for next-generation probes for ultra-sensitive molecular imaging from the cellular scale to whole-body evaluation. It also introduces an easy methodology to quantify in vivo biodistribution of nanomaterials which still needs further understanding as a community.

  4. Effects of gamma-irradiation and air annealing on Yb-doped Y3Al5O12 single crystal.

    PubMed

    Zeng, Xionghui; Xu, Xiaodong; Wang, Xiaodan; Zhao, Zhiwei; Zhao, Guangjun; Xu, Jun

    2008-03-01

    The effects of gamma-irradiation on the air-annealed 10at.% Yb:Y(3)Al(5)O(12) (YAG) and air annealing on the gamma-irradiated 10at.% Yb:YAG have been studied by the difference absorption spectra before and after treatment. The gamma-irradiation and air annealing led to opposite changes of the absorption properties of the Yb:YAG crystal. After air annealing, the gamma-irradiation induced centers were totally removed and the concentration of Fe(3+) and Yb(3+) were lightly increased. For the first time, the gamma-irradiation induced valence changes between Yb(3+) and Yb(2+) ions in Yb:YAG crystals have been observed.

  5. Characterization of Pr:LuAG scintillating crystals for X-ray spectroscopy

    NASA Astrophysics Data System (ADS)

    Bertoni, R.; Bonesini, M.; Cervi, T.; Clemenza, M.; De Bari, A.; Falcone, A.; Mazza, R.; Menegolli, A.; Nastasi, M.; Rossella, M.

    2016-07-01

    The main features of the Pr doped Lu3Al5O12 (Pr:LuAG) scintillating crystals for X-ray spectroscopy applications have been studied using different radioactive sources and photo-detectors. Pr:LuAG is cheaper, compared to a Germanium detector, but with remarkable properties which make it useful for many applications, from fundamental physics measurements to the PET imaging for medical purposes: high density, elevate light yield, fast response, high energy resolution, no hygroscopicity. A sample of Pr:LuAG crystals with 14 mm×14 mm surface area and 13 mm thickness and a NaI crystal of the same surface and 26 mm thickness used as a reference have been characterized with several radioactive sources, emitting photons in the range 100-1000keV. Different light detectors were adopted for the Pr:LuAG studies, sensitive to its UV emission (peak at 310 nm): a 3 in. PMT (Hamamatsu R11065) and new arrays of Hamamatsu SiPM S13361, with siliconic resin as a window. Preliminary results are presented on the performance of the Pr:LuAG crystals, to be mounted in a 2 × 2 array to be tested in the 2015 run of the FAMU experiment at RIKEN-RAL muon facility. The goal is the detection of the X-rays (around 130 keV) emitted during the de-excitation processes of the muonic hydrogen after the excitation with an IR laser with wavelength set at the resonance of the hyperfine splitting, to measure the muonic atom proton radius with unprecedented precision.

  6. A deeper insight into (Lu,Y)AG:Pr scintillator crystals

    NASA Astrophysics Data System (ADS)

    Drozdowski, W.; Wojtowicz, A. J.; Brylew, K.; Łachmański, W.; Talik, E.; Szubka, M.; Kusz, J.; Guzik, A.; Balin, K.; Kisielewski, J.; Świrkowicz, M.; Pajączkowska, A.

    2017-02-01

    Interior of Czochralski-grown (Lu,Y)AG:Pr crystals has been examined by means of several techniques, such as X-Ray Photoelectron Spectroscopy, X-Ray Diffraction, Time-of-Flight Secondary Ion Mass Spectrometry, and magnetic susceptibility measurements. Additionally, their luminescence has been monitored at various combinations of a double-beam (X-ray/IR) excitation.

  7. Three-phonon stimulated Raman scattering in an orthorhombic LuAlO3 crystal

    NASA Astrophysics Data System (ADS)

    Kaminskii, A. A.

    2016-12-01

    High-order stimulated Raman scattering (SRS) has been revealed in a LuAlO3 crystal upon stationary picosecond laser excitation. All recorded Stokes and anti-Stokes χ(3)-nonlinear laser components are attributed to three SRS-promoting A g vibrational modes of its octahedral anionic units (AlO3)-3.

  8. Enhancement of red upconversion emission of cubic phase NaLuF{sub 4}: Yb{sup 3+}/Ho{sup 3+}/Ce{sup 3+} nanocrystals

    SciTech Connect

    Gao, Wei Dong, Jun Liu, Jihong; Yan, Xuewen

    2016-08-15

    Highlights: • The upconversion emission of Ho{sup 3+} ions was tuned from green to red. • The upconversion mechanism of Ho{sup 3+} ions was discussed based on emission spectrum. • The conversion efficiency between Ho{sup 3+} and Ce{sup 3+} were studied and calculated. - Abstract: The red upconversion emission of lanthanide-doped fluoride nanocrystals have great potential applications in color display and anticounterfeiting applications, especially for biological imaging and biomedical. In this work, a significant enhancement of red upconversion emission of Ho{sup 3+} ions was successfully obtained in the cubic phase NaLuF{sub 4} nanocrystals through codoping Ce{sup 3+} ions under NIR 980 nm excitation. The ratio of red-to-green emission of Ho{sup 3+} ions was enhanced about 10-fold, which is due to two efficient cross relaxation processes derived from Ho{sup 3+} and Ce{sup 3+} ions promoted the red emission and quenched the green emission. The upconversion emission and luminescent colors of NaLuF{sub 4}: Yb{sup 3+}/Ho{sup 3+} nanocrystals were carefully investigated by a confocal microscopy setup. The possible upconversion emission mechanism and conversion efficiency of cross relaxation between Ho{sup 3+} and Ce{sup 3+} ions were discussed in detail. The current study suggests that strong red emission of NaLuF{sub 4}: Yb{sup 3+}/Ho{sup 3+}/Ce{sup 3+} nanomaterials can be used for color display and anticounterfeiting techniques.

  9. Spectroscopy and laser performance of Nd:Lu_2O_3 crystal

    NASA Astrophysics Data System (ADS)

    Hao, Liangzhen; Wu, Kui; Cong, Hengjiang; Yu, Haohai; Zhang, Huaijin; Wang, Zhengping; Wang, Jiyang

    2011-08-01

    The spectra of Nd3+:Lu2O3 crystal have been examined at room temperature. Judd-Ofelt theory was applied to calculate the spectral parameters of the crystal. With a laser diode as pump source, a continuous-wave laser output power of 2.81 W is achieved, which is the highest value ever reported in this crystals to our knowledge, and its wavelength is also found to be dual-wavelength. Because of the emission cross-section at 1076 nm and 1080 nm are almost identical, laser oscillation for such two wavelengths can be obtained simultaneously. All the properties show that Nd:Lu2O3 is an excellent crystal for laser applications.

  10. Synthesis of Multicolor Core/Shell NaLuF4:Yb3+/Ln3+@CaF2 Upconversion Nanocrystals

    PubMed Central

    Li, Hui; Hao, Shuwei; Yang, Chunhui; Chen, Guanying

    2017-01-01

    The ability to synthesize high-quality hierarchical core/shell nanocrystals from an efficient host lattice is important to realize efficacious photon upconversion for applications ranging from bioimaging to solar cells. Here, we describe a strategy to fabricate multicolor core @ shell α-NaLuF4:Yb3+/Ln3+@CaF2 (Ln = Er, Ho, Tm) upconversion nanocrystals (UCNCs) based on the newly established host lattice of sodium lutetium fluoride (NaLuF4). We exploited the liquid-solid-solution method to synthesize the NaLuF4 core of pure cubic phase and the thermal decomposition approach to expitaxially grow the calcium fluoride (CaF2) shell onto the core UCNCs, yielding cubic core/shell nanocrystals with a size of 15.6 ± 1.2 nm (the core ~9 ± 0.9 nm, the shell ~3.3 ± 0.3 nm). We showed that those core/shell UCNCs could emit activator-defined multicolor emissions up to about 772 times more efficient than the core nanocrystals due to effective suppression of surface-related quenching effects. Our results provide a new paradigm on heterogeneous core/shell structure for enhanced multicolor upconversion photoluminescence from colloidal nanocrystals. PMID:28336867

  11. Origin of Quantum Criticality in Yb-Al-Au Approximant Crystal and Quasicrystal

    NASA Astrophysics Data System (ADS)

    Watanabe, Shinji; Miyake, Kazumasa

    2016-06-01

    To get insight into the mechanism of emergence of unconventional quantum criticality observed in quasicrystal Yb15Al34Au51, the approximant crystal Yb14Al35Au51 is analyzed theoretically. By constructing a minimal model for the approximant crystal, the heavy quasiparticle band is shown to emerge near the Fermi level because of strong correlation of 4f electrons at Yb. We find that charge-transfer mode between 4f electron at Yb on the 3rd shell and 3p electron at Al on the 4th shell in Tsai-type cluster is considerably enhanced with almost flat momentum dependence. The mode-coupling theory shows that magnetic as well as valence susceptibility exhibits χ ˜ T-0.5 for zero-field limit and is expressed as a single scaling function of the ratio of temperature to magnetic field T/B over four decades even in the approximant crystal when some condition is satisfied by varying parameters, e.g., by applying pressure. The key origin is clarified to be due to strong locality of the critical Yb-valence fluctuation and small Brillouin zone reflecting the large unit cell, giving rise to the extremely-small characteristic energy scale. This also gives a natural explanation for the quantum criticality in the quasicrystal corresponding to the infinite limit of the unit-cell size.

  12. Comparison of the luminescent properties of LuAG:Pr nanopowders, crystals and films using synchrotron radiation

    NASA Astrophysics Data System (ADS)

    Gorbenko, V.; Zych, E.; Voznyak, T.; Nizankovskiy, S.; Zorenko, T.; Zorenko, Yu.

    2017-04-01

    Comparison of the luminescent properties of nanopowder, single crystal and single crystalline film of Pr3+ doped Pr-doped Lu3Al5O12 garnet (LuAG:Pr) prepared by the different technological methods is performed in this work using the time-resolved emission spectroscopy under excitation by synchrotron radiation with an energy of 3.7-25 eV at 300 K and 10 K. The notable differences in the properties of the Pr3+ luminescence are observed in LuAG:Pr crystals and films caused by involving the LuAl antisite defects and oxygen vacancies in crystals and Pb2+ flux related dopant in films in the excitation processes of the Pr3+ luminescence. At the same time, we have also found that the influence of host defects on the Pr3+ luminescence is significantly smaller in the LuAG:Pr nanopowders.

  13. Simultaneously optimizing fluorescent and paramagnetic properties of bifunctional NaGdF{sub 4}:Yb{sup 3+}/Er{sup 3+} nanocrystals by crystal field tuning

    SciTech Connect

    Wu, Xiaofeng; Hu, Shigang; Tan, Congbing; Liu, Yunxin

    2015-04-15

    Graphical abstract: Crystal field tuning is a powerful approach for simultaneously enhancing the optical and magnetic properties of lanthanide-doped NaGdF{sub 4} bi-functional nanocrystals. - Abstract: Here, we show the simultaneous enhancement of fluorescent and paramagnetic properties in bifunctional NaGdF{sub 4}:Yb{sup 3+}/Er{sup 3+} nanocrystals by crystal field tuning. The energy level splitting calculation indicates, that lanthanide ionic pairs La{sup 3+}/Lu{sup 3+} introduced into the NaGdF{sub 4} host can modify the crystal field around emitters (e.g., Er{sup 3+} and Tm{sup 3+}) and sensitizers (e.g., Yb{sup 3+}) that result in the broadening of crystal field splitting of energy levels and the abundant multi-site distribution of upconversion luminescence. The optimization of the paramagnetic properties in NaGdF{sub 4} doped with emitters and sensitizers is ascribed to the lowering of anti-ferromagnetic coupling.

  14. Observation of Systematic Variation in Yb Ion Valence as a Function of Interatomic Spacing in Icosahedral Approximant Crystals

    NASA Astrophysics Data System (ADS)

    Hayashi, Minami; Deguchi, Kazuhiko; Matsukawa, Shuya; Imura, Keiichiro; Sato, Noriaki K.

    2017-04-01

    We discovered two alloy systems, Pd-Ga-Yb and Pd-Ge-Yb, that belong to the Tsai-type 1/1 approximant to the Au-Al-Yb quasicrystal exhibiting the unusual quantum criticality and show a similar behavior to Kondo lattice systems with a magnetically ordered ground state. Combining the results of other Yb-based approximant crystals, we find that there is a systematic variation in the Yb ion valence vs the lattice constant. This proves that the Au-Al-Yb approximant is located at the border of the valence change, in favor of the idea that the valence fluctuation plays a crucial role in the quantum criticality of the Au-Al-Yb system.

  15. Optical spectroscopy of Nd3+ in LiLuF4 single crystals

    NASA Astrophysics Data System (ADS)

    Zhao, Chengchun; Zhang, Lianhan; Hang, Yin; He, Xiaoming; Yin, Jigang; Hu, Pengchao; Chen, Guangzhu; He, Mingzhu; Huang, Huang; Zhu, Yongyuan

    2010-12-01

    The polarized absorption spectra, polarized fluorescence spectra and fluorescence decay curve of Nd3+ : LiLuF4 crystals are measured at room temperature. The peak absorption cross-sections are 6.944×10-20 cm2 and 1.664 × 10-20 cm2 at around 795 nm with full-width at half-maximum of 3.4 nm and 3.2 nm for π-polarization and σ-polarization, respectively. Based on Judd-Ofelt theory, the spectral parameters of Nd3+ in LiLuF4 crystals are investigated. The emission probabilities, branching ratio and radiative lifetime for the transitions from 4F3/2 are calculated. The radiative lifetime, fluorescence lifetime and quantum efficiency are 536 µs, 489 µs and 91%, respectively. Its spectroscopic parameters are also compared with those of some other important Nd3+-doped laser crystals.

  16. Use of YB(66) as monochromator crystals for soft-energy EXAFS.

    PubMed

    Smith, A D; Cowie, B C; Sankar, G; Thomas, J M

    1998-05-01

    YB(66)(400) crystals present a new advance in monochromator crystals suitable for use at energies below 2 keV. In this paper a comparison of their performance with that provided by the more usual beryl and quartz crystals, which cover the same energy range, is presented. In general, the YB(66) crystals are much superior; however, they do exhibit a pair of large 'crystal glitch'-type features in the 1380-1440 eV region. These fall in the Mg K-EXAFS region and so can present a serious problem in studies of this edge for a wide range of materials. An important class of materials so afflicted are magnesium-substituted aluminophosphate molecular sieves (zeolites), which are used in many applications, in particular as solid acid catalysts for conversion of methanol to hydrocarbon.

  17. Controllable red, green, blue (RGB) and bright white upconversion luminescence of Lu2O3:Yb3+/Er3+/Tm3+ nanocrystals through single laser excitation at 980 nm.

    PubMed

    Yang, Jun; Zhang, Cuimiao; Peng, Chong; Li, Chunxia; Wang, Lili; Chai, Ruitao; Lin, Jun

    2009-01-01

    Light fantastic! Lu(2)O(3):Yb(3+)/Er(3+)/Tm(3+) nanocrystals with controllable red, green, blue (RGB) and bright white upconversion luminescence by a single laser excitation of 980 nm have been successfully synthesized (see picture). Due to abundant UC PL colors, it can potentially be used as fluorophores in the field of color displays, back light, UC lasers, photonics, and biomedicine.Lu(2)O(3):Yb(3+)/Er(3+)/Tm(3+) nanocrystals have been successfully synthesized by a solvothermal process followed by a subsequent heat treatment at 800 degrees C. Powder X-ray diffraction, transmission electron microscopy, upconversion photoluminescence spectra, and kinetic decay were used to characterize the samples. Under single-wavelength diode laser excitation of 980 nm, the bright blue emissions of Lu(2)O(3):Yb(3+), Tm(3+) nanocrystals near 477 and 490 nm were observed due to the (1)G(4)-->(3)H(6) transition of Tm(3+). The bright green UC emissions of Lu(2)O(3):Er(3+) nanocrystals appeared near 540 and 565 nm were observed and assigned to the (2)H(11/2)-->(4)I(15/2) and (4)S(3/2)-->(4)I(15/2) transitions, respectively, of Er(3+). The ratio of the intensity of green luminescence to that of red luminescence decreases with an increase of concentration of Yb(3+) in Lu(2)O(3):Er(3+) nanocrystals. In sufficient quantities of Yb(3+) with resprct to Er(3+), the bright red UC emission of Lu(2)O(3):Yb(3+)/Er(3+) centered at 662 nm was predominant, due to the (4)F(9/2)-->(4)I(15/2) transition of Er(3+). Based on the generation of red, green, and blue emissions in the different doped Lu(2)O(3):RE(3+) nanocrystals, it is possible to produce the luminescence with a wide spectrum of colors, including white, by the appropriate doping of Yb(3+), Tm(3+), and Er(3+) in the present Lu(2)O(3) nanocrystals. Namely, Lu(2)O(3):3 %Yb(3+)/0.2 %Tm(3+)/0.4 %Er(3+) nanocrystals show suitable intensities of blue, green, and red (RGB) emission, resulting in the production of perfect and bright white light

  18. Structural characterization of Lu1.8Y0.2SiO5 crystals

    NASA Astrophysics Data System (ADS)

    Chiriu, Daniele; Faedda, Nicola; Lehmann, Alessandra Geddo; Ricci, Pier Carlo; Anedda, Alberto; Desgreniers, Serge; Fortin, Emery

    2007-08-01

    The structural and vibrational properties of Lu1.8Y0.2SiO5 (LYSO) single crystals were investigated by means of Raman spectroscopy and x-ray diffraction measurements. Unit cell parameters and bond lengths were determined by Rietveld refinement of the collected x-ray diffraction powder spectra. By comparison with the vibrational spectra of the parent compounds Lu2SiO5 and Y2SiO5 and by using polarized Raman measurements, we propose the assignment of the principal vibrational modes of LYSO crystals. The strict connection of Raman spectra of the LYSO solid solution and of the pure lutetium and yttrium crystals, as well as the analysis of the polarized measurements, confirms that LYSO structure adopts the C2/c space group symmetry. The structural analogies of LYSO with the pure compound Lu2SiO5 are further shown by means of high pressure Raman spectroscopy, and the possibility of considering the LYSO crystal analogous to the LSO structure with a tensile stress between 0.25 and 0.80GPa is discussed.

  19. Characterization and comparison of 1% at Yb-doped Lu2O3 and Sc2O3 ceramics as laser gain media

    NASA Astrophysics Data System (ADS)

    Pirri, A.; Toci, G.; Vannini, M.

    2012-12-01

    We present the first laser oscillation achieved on Yb-doped Sc2O3 and Lu2O3 ceramics with a level of doping as low as 1 at %, under quasi-continuous wave pumping at 968 nm. Ceramic samples reached comparable performances in terms of tunability ranges, which exceeds 41 nm, and laser output powers. In particular, with the former sample emitting at 1040.5 nm we measured a maximum output power of 2.2 W with a corresponding slope efficiency of η = 59%. The latter medium delivered 1.8 W with a slope of η = 45% at 1032.5 nm while at 1078 nm we measured 1.5 W with η = 34%. Finally, we report the measured level of the Amplified Spontaneous Emission (ASE) for both samples, which was found to be less than 0.1 mW at the maximum pump power.

  20. High performance silica micro-tube optical temperature sensor based on β-NaLuF4:Yb3+/Tm3+ nanocrystals

    NASA Astrophysics Data System (ADS)

    Li, Hui; Zhang, Yundong; Shao, Lin; Wu, Yongfeng; Htwe, ZinMaung; Yuan, Ping

    2017-07-01

    Rare earth co-doped nanocrystals of β-NaLuF4: Yb3+/Tm3+ with a uniform morphology and hexagonal structure were synthesized by a solvothermal route. The structure of the synthesized material was investigated with X-ray diffraction, scanning electron microscope and transmission electron microscope techniques. The micro-tube structure including rare earth nanocrystals was achieved by drawing the SiO2 capillary under the flame. The fluorescence intensity ratio of non-thermal coupling levels of 1D2→3F4 and 1G4→3H6 were studied as a function of temperature around the range of 300-550 K. The maximum sensitivity was estimated to be 0.0047 K-1 at 525 K. These results indicated that the device may have great potential applications in optical temperature sensor.

  1. Progress in the Growth of Yb:S-FAP Laser Crystals

    SciTech Connect

    Schaffers, K I; Tassano, J B; Waide, P A; Payne, S A; Morris, R C

    2000-07-01

    The crystal growth of Yb:S-FAP [Yb{sup 3+}:Sr{sub 5}(PO{sub 4}){sub 3}F] is being studied for 1.047-{micro}m laser operation. These crystals are not yet routinely available and the growth of high optical quality, low loss crystals poses a challenge due to a number of crystal growth issues, including, cloudiness, bubble core defects, anomalous absorption, low-angle grain boundaries, and cracking. At this time, a growth process has been formulated to simultaneously eliminate or greatly diminish each of the defects yielding high quality material. Laser slabs of dimension 4.0 x 6.0 x 0.75 cm are being fabricated from sub-scale pieces using the diffusion bonding technique.

  2. Green up-converted luminescence in (Er3+-Yb3+) co-doped LiNbO3 crystals

    NASA Astrophysics Data System (ADS)

    Stoffel, M.; Rinnert, H.; Kokanyan, E.; Demirkhanyan, G.; Demirkhanyan, H.; Aillerie, M.

    2016-07-01

    Er3+ doped and (Er3+-Yb3+) co-doped LiNbO3 (LN) crystals grown by the Czochralski method are investigated by photoluminescence spectroscopy. Green up-converted luminescence is observed in Er3+ doped LN crystals under 980 nm excitation. This is explained by an energy transfer between two neighboring Er3+ ions. In (Er3+, Yb3+) co-doped LN crystals, the intensity of the green up-converted luminescence can be further enhanced suggesting that Yb3+ ions also contribute to the up-conversion process. Time resolved photoluminescence measurements clearly demonstrate that an efficient energy transfer occurs between Yb3+ and Er3+ ions. A theoretical model taking into account the contribution of both Er3+-Er3+ pairs and Yb3+-Er3+ pairs is able to describe correctly the decay of the up-converted luminescence.

  3. Stokes and anti-Stokes luminescence in Tm(3+)/Yb(3+)-doped Lu3Ga5O12 nano-garnets: a study of multipolar interactions and energy transfer dynamics.

    PubMed

    Rathaiah, Mamilla; Haritha, Pamuluri; Lozano-Gorrín, Antonio Diego; Babu, Palamandala; Jayasankar, Chalicheemalapalli Kulala; Rodríguez-Mendoza, Ulises Ruyman; Lavín, Victor; Venkatramu, Vemula

    2016-06-07

    Nanocrystalline Lu3Ga5O12 garnets doped with Tm(3+)/Yb(3+) ions have been synthesized by a low cost and environmentally benign sol-gel technique and characterized for their structural, Stokes and anti-Stokes luminescence properties. The diffuse reflectance spectra of doped Lu3Ga5O12 nano-garnets have been measured to derive the partial energy level structure of Tm(3+) and Yb(3+) ions and possible energy transfer channels between them. Upon laser excitation at 473 nm, weak red and intense near-infrared Stokes emissions have been observed in the nano-garnets. The decay curves of (3)H4 and (1)G4 levels of Tm(3+) ions and the (2)F5/2 level of Yb(3+) ions have been measured upon resonant laser excitation and are found to be non-exponential in nature due to multipolar interactions. In order to know the kind of multipolar interaction among optically active ions, the decay curves are analyzed through the generalized Yokota-Tanimoto model. Moreover, under 970 nm laser excitation, intense blue anti-Stokes emission is observed by the naked eye in Tm(3+)-Yb(3+) co-doped Lu3Ga5O12 nano-garnets. The results show that as-synthesized nano-garnets may be useful in the field of phosphors and photonics.

  4. Infrared and Raman spectra of tris(dipivaloylmethanato) lanthanides, Ln(thd)3 (Ln = La, Nd, Eu, Gd, Tb, Ho, Er, Tm, Yb, Lu)

    NASA Astrophysics Data System (ADS)

    Belova, Natalya V.; Sliznev, Valery V.; Christen, Dines

    2017-03-01

    The infrared and Raman vibrational spectra of the series of solid tris(dipivaloylmethanato) lanthanides, Ln(thd)3 (Ln = La, Nd, Eu, Gd, Tb, Ho, Er, Tm, Yb, Lu), have been recorded at room temperature over wide ranges (4000-50 cm-1 and 3500-80 cm-1, respectively). The experimental spectra obtained in the present study were successfully assigned based on the quantum chemical calculations (DFT/PBE0) performed for the monomer Ln(thd)3 molecules. The experimental vibrational spectra for all complexes studied are rather similar as are the theoretical simulations. The data analysis shows that the main contributions to vibrational modes arise from the vibrations of the ligand possessing practically the same geometry for all complexes. According to the calculation results the structure of the coordination polyhedron is increasingly distorted in the series from La(thd)3 to Lu(thd)3. Although the contributions of the polyhedron vibrations in vibrational modes are not predominant, there is rise in the frequencies associated with vibrations of the coordination polyhedron LnO6 in this series. This increase has been explained by the concept of lanthanide contraction.

  5. PHOTONIC CRYSTAL SURFACE ENHANCED UPCONVERSION EMISSION OF YF3:Yb3+, Er3+ NANOPARTICLES

    NASA Astrophysics Data System (ADS)

    Shao, Bo; Yang, Zhengwen; Li, Jun; Liao, Jiayan; Lai, Shenfeng; Qiu, Jianbei; Song, Zhiguo; Yang, Yong; Zhou, Dacheng

    2015-11-01

    The opal photonic crystals made of polystyrene microspheres with 155, 230, 270 or 410 nm in diameter were used to enhance upconversion (UC) emission of YF3:Yb3+, Er3+ nanoparticles, respectively. The red or green UC emission of YF3:Yb3+, Er3+ nanoparticles can be selectively enhanced when the red or green UC emission wavelength overlapped with the photonic bandgaps of opals, which is attributed to Bragg reflection of photonic bandgap. In addition, when the 980 nm excitation light wavelength was in the region of the photonic bandgap, red and green UC emissions of YF3:Yb3+, Er3+ nanoparticles were enhanced due to the enhancement of excitation field.

  6. Infrared to visible upconversion fluorescence in Yb,Tm:YAG single crystal

    NASA Astrophysics Data System (ADS)

    Xu, Wenwei; Xu, Xiaodong; Wu, Feng; Zhao, Guangjun; Zhao, Zhiwei; Zhou, Guoqing; Xu, Jun

    2007-04-01

    Absorption spectrum from 400 to 2000 nm and upconversion fluorescence spectra under 940 nm pumping of YAG single crystal codoped with 5 at.% Yb3+ and 4 at.% Tm3+ were studied at room temperature. The blue upconversion emission centered at 483 nm corresponds to the transition 1G4 → 3H6, the emission band around 646 nm corresponds to the transition 1G4 → 3F4 of Tm3+. Energy transfer from Yb3+ to Tm3+ is mainly nonradiative and the transfer efficiency was experimentally assessed. The line strengths, transition probabilities and radiative lifetimes of 1G4 level were calculated by using Judd-Ofelt theory. Gain coefficient calculated from spectra shows that the upconversion corresponding with transitions 1G4 → 3H6 in YAG doped with Yb3+ and Tm3+ is potentially useful for blue light output.

  7. Microchip laser based on Yb:YAG/V:YAG monolith crystal

    NASA Astrophysics Data System (ADS)

    Nejezchleb, Karel; Šulc, Jan; Jelínková, Helena; Škoda, Václav

    2016-03-01

    V:YAG crystal was investigated as a passive Q-switch of longitudinally diode-pumped microchip laser, emitting radiation at wavelength 1030.5 nm. This laser was based on diffusion bonded monolith crystal (diameter 3 mm) which combines in one piece an active laser part (Yb:YAG crystal, 10 at.% Yb/Y, 3 mm long) and saturable absorber (V:YAG crystal, 2 mm long, initial transmission 86 % @ 1031 nm). The microchip resonator consisted of dielectric mirrors directly deposited on the monolith surfaces (pump mirror HT @ 968 nm and HR @ 1031 nm on Yb:YAG part, output coupler with reflection 55 % @ 1031 nm on the V:YAG part). For longitudinal CW pumping of Yb:YAG part, a fibre coupled (core diameter 100 μm, NA = 0.22, emission @ 968 nm) laser diode was used. The laser threshold was 3.8W. The laser slope efficiency for output mean in respect to incident pumping was 16 %. The linearly polarized generated transversal intensity beam profile was close to the fundamental Gaussian mode. The generated pulse length, stable and mostly independent on pumping power, was equal to 1.3 ns (FWHM). The single pulse energy was increasing with the pumping power and for the maximum pumping 9.7W it was 78 μJ which corresponds to the pulse peak-power 56 kW. The maximum Yb:YAG/V:YAG microchip laser mean output power of 1W was reached without observable thermal roll-over. The corresponding Q-switched pulses repetition rate was 13.1 kHz.

  8. Time-resolved spectroscopy of intrinsic luminescence of Y 3Ga 5O 12 and (LaLu) 3Lu 2Ga 3O 12 single crystals

    NASA Astrophysics Data System (ADS)

    Zorenko, Yu.; Zorenko, T.; Vistovskyy, V.; Grinberg, M.; Łukasiewicz, T.

    2009-10-01

    The nature of intrinsic luminescence of Y 3Ga 5O 12 (YGG) and (LaLu) 3Lu 2Ga 3O 12 (LLGG) single crystals grown from a melt was determined. In the case of a YGG single crystal containing Y Ga antisite defects with a concentration of 0.25-0.275 at.% the intrinsic luminescence was considered as a superposition of luminescence of self-trapped excitons (STE), luminescence of excitons localized near antisite defects (LE(AD) centers) and luminescence caused by a recombination of an electron with a hole captured at Y Ga antisite defects. Due to a large (2-3%) concentration of Lu La antisite defects in LLGG single crystals the intrinsic luminescence was a superposition mainly of the LE(AD) center emission and the recombination luminescence of Lu La antisite defects. The energy structure of the mentioned centers in YGG and LGGG hosts was determined from the excitation spectra of their luminescence under excitation by synchrotron radiation in the range of the fundamental absorption edge of these garnets.

  9. The photoluminescence response to structural changes of Yb implanted ZnO crystals subjected to non-equilibrium processing

    NASA Astrophysics Data System (ADS)

    Ratajczak, R.; Prucnal, S.; Guziewicz, E.; Mieszczynski, C.; Snigurenko, D.; Stachowicz, M.; Skorupa, W.; Turos, A.

    2017-02-01

    In this paper, we present the detailed study of optical and structural properties of Yb implanted single ZnO crystals. Hydrothermally grown wurtzite (0001) ZnO crystals were implanted with 150 keV Yb ions to fluencies of 5 × 1014 and 1 × 1015 at/cm2. After ion implantation, two different types of annealing were performed: rapid thermal annealing (RTA) and millisecond range flash lamp annealing (FLA). Crystalline quality, damage recovery, and Yb lattice site location were evaluated by the Channeling Rutherford Backscattering Spectrometry (RBS/c). It is shown that independent of the used annealing technique, defects formed in ZnO during ion implantation can be removed. Upon RTA performed at the temperature higher than 800 °C, strong out-diffusion of implanted Yb atoms and precipitation on the surface takes place. Consequently, the degradation of the photoluminescence (PL) efficiency is observed. The diffusion of implanted Yb during millisecond range FLA does not occur for such experimental conditions. Moreover, FLA treatment for 20 ms leads to the formation of single crystalline ZnO layer with Yb incorporated in the substitutional lattice sites. According to RBS/c and PL data, Yb atoms substituted in the Zn sublattice are predominantly in the 2+ oxidation state. The most intensive PL has been observed after annealing at 800 °C for 20 min which is accompanied with the reduction of Yb substitutional fraction and formation of octahedron Yb-oxygen clusters within ZnO.

  10. Luminescent and scintillation properties of Lu3Al5O12:Sc single crystal and single crystalline films

    NASA Astrophysics Data System (ADS)

    Zorenko, Y.; Gorbenko, V.; Voznyak, T.; Savchyn, V.; Nizhankovskiy, S.; Dan'ko, A.; Puzikov, V.; Laguta, V.; Mares, J. A.; Nikl, M.; Nejezchleb, K.; Batentschuk, M.; Winnacker, A.

    2012-10-01

    The work is dedicated to growth by the liquid phase epitaxy method and study of the luminescence and scintillation properties of Sc3+ doped single crystalline films (SCF) of Lu3Al5O12 (LuAG) garnet. The scintillation properties of SCF are compared with single crystal (SC) analogues grown by the Horizontal Direct Crystallization and Czochralski methods. We consider the dependence of intensity of the Sc3+ emission in LuAG host on the activator concentration and influence of flux contamination on the light yield (LY) of the Sc3+ luminescence in LuAG:Sc SCF with respect to their SC counterparts and the reference YAP:Ce scintillator. From the NMR investigations of LuAG:Sc SCF we confirm the substitution by Sc3+ ions both the octahedral and dodecahedral positions of LuAG host and formation of the ScAl and ScLu related emission centers, respectively. We also show that the luminescence spectrum in the UV range and decay kinetics of LuAG:Sc SCF can be effectively tuned by changing the scandium content.

  11. Passive Q-switching of Yb bulk lasers by a graphene saturable absorber

    NASA Astrophysics Data System (ADS)

    Loiko, P. A.; Serres, J. M.; Mateos, X.; Liu, J.; Zhang, H.; Yasukevich, A. S.; Yumashev, K. V.; Petrov, V.; Griebner, U.; Aguiló, M.; Díaz, F.

    2016-04-01

    Compact Yb:KLu(WO4)2 and Yb:LuVO4 lasers diode-pumped at 978 nm are passively Q-switched by a single-layer graphene saturable absorber. The Yb:KLu(WO4)2 laser generated 165 ns/0.49 μJ pulses at 1030 nm with 170 mW average output power and 12 % slope efficiency. With the Yb:LuVO4 laser, 152 ns/0.83 μJ pulses were achieved. The output power reached 300 mW at 1024 nm, and the slope efficiency was 10 %. Laser operation in a plano-plano cavity is achieved with both crystals with thermal lensing playing a key role in their performance. A model describing graphene Q-switched Yb lasers is developed. Our results indicate the potential of graphene for passive Q-switching of ~1 μm bulk lasers.

  12. Effects of Yb concentration on the fluorescence spectra of Yb-doped YAlO3 single crystals.

    PubMed

    Zeng, Xionghui; Zhao, Guangjun; Xu, Jun

    2006-09-01

    0.5 at.% Yb:YAlO(3)(YAP), 5 at.% Yb:YAP and 15 at.% Yb:YAP were grown using the Czochralski method. Their absorption and fluorescence spectra were measured at room temperature and their emission line shape was calculated using the method of reciprocity. It was observed that the fluorescence spectra changed appreciably with the increasing of Yb concentration. For 0.5 at.% Yb:YAP, the line shape of fluorescence is very similar with the calculated emission line shape; with the increasing of Yb doping concentration, the line shape of fluorescence is very different from the calculated emission line shape. These phenomena are caused by the strong self-absorption at 979 and 999 nm for Yb:YAP.

  13. Research on YB68 for Microwave Acoustic Crystals

    DTIC Science & Technology

    1974-11-01

    suitable at present for delay lines because of problems with crystal growth and an anomalous acoustic attenuation that appears to be closely associated with... Crystals . . . 67 A. Background ....... ................. .... 67 B. Growth Methods ....... ................ .. 69 Synthesis . ..................... .... 69...50 10 Impurities in Yttrium Metal ........ .............. ... 72 11 Crystal Growth Runs ........ ................. .... 72 12 Density, X-Ray

  14. Optical properties of Mg2+, Yb3+, and Ho3+ tri-doped LiNbO3 crystals

    NASA Astrophysics Data System (ADS)

    Dai, Li; Liu, Chun-Rui; Tan, Chao; Yan, Zhe-Hua; Xu, Yu-Heng

    2017-04-01

    A series of LiNbO3 crystals tri-doped with Mg{}2+, Yb{}3+, and Ho{}3+ are grown by the conventional Czochraski technique. The concentrations of Mg{}2+, Yb{}3+, and Ho{}3+ ions in Mg:Yb:Ho:LiNbO3 crystals are measured by using an inductively coupled plasma atomic emission spectrometry. The x-ray diffraction is proposed to determine the lattice constant and analyze the internal structure of the crystal. The light-induced scattering of Mg:Yb:Ho:LiNbO3 crystal is quantitatively described via the threshold effect of incident exposure energy flux. The exposure energy ({E}{{r}}) is calculated to discuss the optical damage resistance ability. The exposure energy of Mg(7 mol):Yb:Ho:LiNbO3 crystal is 709.17 J/cm2, approximately 425 times higher than that of the Mg(1 mol):Yb:Ho:LiNbO3 crystal in magnitude. The blue, red, and very intense green bands of Mg:Yb:Ho:LiNbO3 crystal are observed under the 980-nm laser excitation to evaluate the up-conversion emission properties. The dependence of the emission intensity on pumping power indicates that the up-conversion emission is a two-photon process. The up-conversion emission mechanism is discussed in detail. This study indicates that Mg:Yb:Ho:LiNbO3 crystal can be applied to the fabrication of new multifunctional photoluminescence devices. Project supported by the National Natural Science Foundation of China (Grant No. 51301055), the Youth Science Fund of Heilongjiang Province, China (Grant No. QC2015061), the Special Funds of Harbin Innovation Talents in Science and Technology Research, China (Grant No. 2015RQQXJ045 ), and the Science Funds for the Young Innovative Talents of Harbin University of Science and Technology, China (Grant No. 201501).

  15. Spin wave and spin flip in hexagonal LuMnO3 single crystal

    NASA Astrophysics Data System (ADS)

    Chen, Xiang-Bai; Guo, Peng-Cheng; Huyen, Nguyen Thi; Kim, Seung; Yang, In-Sang; Wang, Xueyun; Cheong, Sang-Wook

    2017-03-01

    Manipulation and control of spin wave and spin flip are crucial for future developments of magnonic and spintronic devices. We present that the spin wave in hexagonal LuMnO3 single crystal can be selectively excited with laser polarization perpendicular to the c-axis of hexagonal LuMnO3 and photon energy ˜1.8 eV. The selective excitation of spin wave also suggests that the spin flip can be selectively controlled in hexagonal manganites. In addition, a microscopic model of the spin wave generation correlated with the four-spin-flip in hexagonal manganites is suggested to account for the line-shape of the observed spin wave.

  16. Energy transfer and lasing in LiYbF4:Ho, LiYbF4:Ho,Tm, and KYb(WO4)3 crystals

    NASA Astrophysics Data System (ADS)

    Sandulenko, Alexander V.; Sandulenko, V. A.; Tkachuk, Alexandra M.; Titov, Alexandre N.; Reiterov, V. M.; Ivanov, V. N.

    1998-12-01

    We have studied both theoretically and experimentally the energy transfer processes in YbLiF4:Ho3+ (0.4%) and YbLiF4:Ho3+ (0.4%),Tm3+ (10%) crystals and in the series of crystals KYb(WO4)2:Tm3+,Ho3+ (0.4%) with the thulium concentration 5; 10; and 20%. The population kinetics of the 5I7 holmium level was studied under the 1.047 micrometers Q-switched YLF:Nd3+ laser pumping. The efficiency of energy transfer processes in Ho3+ doped crystals, codoped with Yb3+ and Tm3+, was demonstrated. With an YbLiF4:Ho3+ (0.4%) laser rod we have obtained lasing at 2.06 micrometers with the total efficiency of 4.8% and the slope efficiency of 11%. In the KYb(WO4)2:Tm3+ (10%),Ho3+ (0.4%) crystal, lasing was obtained for the first time at 2 micrometers . The pumping threshold being approximately 150 mJ, total efficiency 6% and slope efficiency 9.7% was achieved.

  17. Growth of (Er,Yb):YAl{sub 3}(BO{sub 3}){sub 4} laser crystals

    SciTech Connect

    Pilipenko, O. V. Mal'tsev, V. V.; Koporulina, E. V.; Leonyuk, N. I.; Tolstik, N. A.; Kuleshov, N. V.

    2008-03-15

    (Er,Yb):YAl{sub 3}(BO{sub 3}){sub 4} single crystals of optical quality, up to 15 x 10 x 10 mm{sup 3} in size, have been grown from a (Er{sub 0.023}Yb{sub 0.116}Y{sub 0.862})Al{sub 3}(BO{sub 3}){sub 4} solution in a Y{sub 2}O{sub 3}-B{sub 2}O{sub 3}-K{sub 2}Mo{sub 3}O{sub 10} melt. The initial borate concentration was 17 wt %, and the flux cooling rate increased from 0.08 to 0.12 deg. C/h in the range 1060-1000 deg. C. The physical properties of the single crystals grown are good enough that they can be used as laser elements in systems with diode pumping and radiation near 1.5 {mu}m.

  18. Peculiarities in the Raman spectra of ZrB{sub 12} and LuB{sub 12} single crystals

    SciTech Connect

    Werheit, H. . E-mail: helmut.werheit@koeln.de; Paderno, Yu.; Filippov, V.; Paderno, V.; Pietraszko, A.; Armbruester, M.; Schwarz, U.

    2006-09-15

    We have measured Raman spectra of high-quality Zr{sup nat}B{sub 12}, Lu{sup nat}B{sub 12} and Lu{sup 11}B{sub 12} single crystals with high resolution, and the observed strong peaks are attributed to specific vibration modes. Besides, there are a number of additional Raman peaks in spectral ranges, where only Raman-inactive vibrations of the atomic arrangement are expected. Accordingly, it is assumed, that the investigated crystals contain intrinsic structural imperfections or distortions in sufficient concentration and efficiency to initiate the observed breaking of phonon selection rules. We suppose boron vacancies, boron isotope effects and displacements of the metal atoms to be reasons for such imperfections. - Graphical abstract: Raman spectra of Lu{sup nat}B{sub 12}, Lu{sup 11}B{sub 12} and Zr{sup nat}B{sub 12}.

  19. Spectroscopic properties and continuous-wave laser operation of Yb:Bi₄ Si₃ O₁₂ crystal.

    PubMed

    Wang, Han; Chen, Yujin; Huang, Jianhua; Gong, Xinghong; Lin, Yanfu; Luo, Zundu; Huang, Yidong

    2014-09-08

    Yb3+:Bi4Si3O12 single crystal with Yb3+ concentration of 5.7 at.% has been grown successfully by the Czochralski method. The energy level positions of Yb3+ in Bi4Si3O12 crystal were determined based on the absorption and fluorescence spectra. The peak absorption cross-section is 0.98 × 10−20 cm2 at 976 nm and the peak emission cross-section is 0.57 × 10−20 cm2 at 1035 nm. The fluorescence lifetime of the excited multiplet is 1.26 ms. Diode-pumped continuous-wave laser operation around 1038 nm has been demonstrated in the Yb3+:Bi4Si3O12 crystal with a slope efficiency of 27% and maximum output power of 240 mW.

  20. Spectroscopy and laser operation of Indium-modified Yb:KLuW: a promising crystal for femtosecond lasers

    NASA Astrophysics Data System (ADS)

    Mateos, Xavier; Serres, Josep Maria; Loiko, Pavel; Yumashev, Konstantin; Griebner, Uwe; Petrov, Valentin; Aguiló, Magdalena; Díaz, Francesc

    2017-02-01

    We report on the growth, spectroscopic and laser characterization of a novel monoclinic laser crystal, 3.5 at.% Yb, 5.5 at.% In:KLu(WO4)2 (Yb,In:KLuW). Single-crystals of high optical quality are grown by the TSSG method. The absorption, stimulated-emission and gain cross-sections are determined for this material at room temperature with polarized light. The maximum σabs is 9.9×10-20 cm2 at 980.8 nm for light polarization E || Nm. The radiative lifetime of Yb3+ in Yb,In:KLuW is 237+/-5 μs. The stimulated-emission cross-sections are σSE(m) = 2.4×10-20 cm2 at 1022.4 nm and σSE(p) = 1.3×10-20 cm2 at 1039.1 nm corresponding to an emission bandwidth of >30 nm and >35 nm, respectively. A diode-pumped Ng-cut Yb,In:KLuW microchip laser generates 4.11 W at 1047-1052 nm with a slope efficiency of 78%. Passive Q-switching of a Yb,In:KLuW laser is also demonstrated. The Yb,In:KLuW crystal seems very promising for sub-100 fs mode-locked lasers.

  1. Crystal structures and magnetic properties of lanthanide containing borates LnM(BO{sub 3}){sub 2} (Ln=Y, Ho–Lu; M=Sc, Cr)

    SciTech Connect

    Doi, Yoshihiro Satou, Tatsuya; Hinatsu, Yukio

    2013-10-15

    The synthesis, crystal structures and magnetic properties of LnM(BO{sub 3}){sub 2} (Ln=Y, Ho–Lu; M=Sc, Cr) were investigated. The LnCr(BO{sub 3}){sub 2} compounds crystallize in the dolomite-type structure with space group R3{sup ¯}, in which the Ln and Cr ions occupy two octahedral sites. From the result of structural analysis, it was found that there is an anti-site disorder between these two sites and its chemical formula is more exactly Ln{sub 1−r}Cr{sub r}[Cr{sub 1−r}Ln{sub r}](BO{sub 3}){sub 2}. On the other hand, the LnSc(BO{sub 3}){sub 2} adopt the calcite-type structure with space group R3{sup ¯}c. The Ln and Sc ions randomly occupy an octahedral site and the chemical formula is represented as (Ln{sub 0.5}Sc{sub 0.5})BO{sub 3}. From the magnetic susceptibility and specific heat measurements, we found that all the LnCr(BO{sub 3}){sub 2} show an antiferromagnetic transition at 6.1–8.1 K. This transition is mainly due to the ordering of Cr{sup 3+} magnetic moments. Among the compounds with magnetic Ln{sup 3+} ions, only YbCr(BO{sub 3}){sub 2} shows an antiferromagnetic ordering of Ln{sup 3+} ion at 2.1 K. - Graphical abstract: The lanthanide containing borates LnM(BO{sub 3}){sub 2} (Ln=Y, Ho–Lu; M=Sc, Cr) have the dolomite-type (Ln=Cr) and calcite-type (Ln=Sc) structures. Both structures are similar to each other except for the difference in the partially or fully disordered arrangements of octahedral sites. At low temperatures, the LnCr(BO{sub 3}){sub 2} compounds show an antiferromagnetic transition due to a long-range ordering of Cr{sup 3+} moments. Among them only YbCr(BO{sub 3}){sub 2} shows an antiferromagnetic ordering of Ln{sup 3+} ion at 2.1 K. Display Omitted - Highlights: • Lanthanide containing borates LnM(BO{sub 3}){sub 2} (Ln=Y, Ho–Lu; M=Sc, Cr) have been synthesized. • LnCr(BO{sub 3}){sub 2} has the dolomite-type structure with an anti-site disorder between Ln and Cr sites. • LnSc(BO{sub 3}){sub 2} has the calcite

  2. Conduction electron spin resonance in the α-Yb1-xFexAlB4 (0 ⩽ x ⩽ 0.50) and α-LuAlB4 compounds

    NASA Astrophysics Data System (ADS)

    Holanda, L. M.; Lesseux, G. G.; Magnavita, E. T.; Ribeiro, R. A.; Nakatsuji, S.; Kuga, K.; Fisk, Z.; Oseroff, S. B.; Urbano, R. R.; Rettori, C.; Pagliuso, P. G.

    2015-06-01

    β-YbAlB4 has become one of the most studied heavy fermion systems since its discovery due to its remarkable physical properties. This system is the first reported Yb-based heavy-fermion superconductor (HFS) for which the low-T superconducting state emerges from a non-fermi-liquid (NFL) normal state associated with quantum criticality Nakatsuji et al 2008 Nature 4 603. Additionally, it presents a striking and unprecedented electron spin resonance (ESR) signal which behaves as a conduction electron spin resonance (CESR) at high temperatures and acquires features of the Yb3+ local moment ESR at low temperatures. The latter, also named Kondo quasiparticles spin resonance (KQSR), has been defined as a 4f-ce strongly coupled ESR mode that behaves as a local probe of the Kondo quasiparticles in a quantum critical regime, Holanda et al 2011 Phys. Rev. Lett. 107 026402. Interestingly, β-YbAlB4 possesses a previously known structural variant, namely the α-YbAlB4, phase which is a paramagnetic Fermi liquid (FL) at low temperatures Macaluso et al 2007 Chem. Mater. 19 1918. However, it has been recently suggested that the α-YbAlB4 phase may be tuned to NFL behavior and/or magnetic ordering as the compound is doped with Fe. Here we report ESR studies on the α-Yb1-xFexAlB4 (0 ⩽ x ⩽ 0.50) series as well as on the reference compound α-LuAlB4. For all measured samples, the observed ESR signal behaves as a CESR in the entire temperature range (10 K ≲ T ≲ 300 K) in clear contrast with what has been observed for β-YbAlB4. This striking result indicates that the proximity to a quantum critical point is crucial to the occurrence of a KQSR signal.

  3. Conduction electron spin resonance in the α-Yb1-xFexAlB4 (0 ⩽ x ⩽ 0.50) and α-LuAlB4 compounds.

    PubMed

    Holanda, L M; Lesseux, G G; Magnavita, E T; Ribeiro, R A; Nakatsuji, S; Kuga, K; Fisk, Z; Oseroff, S B; Urbano, R R; Rettori, C; Pagliuso, P G

    2015-07-01

    β-YbAlB4 has become one of the most studied heavy fermion systems since its discovery due to its remarkable physical properties. This system is the first reported Yb-based heavy-fermion superconductor (HFS) for which the low-T superconducting state emerges from a non-fermi-liquid (NFL) normal state associated with quantum criticality Nakatsuji et al 2008 Nature 4 603. Additionally, it presents a striking and unprecedented electron spin resonance (ESR) signal which behaves as a conduction electron spin resonance (CESR) at high temperatures and acquires features of the Yb(3+) local moment ESR at low temperatures. The latter, also named Kondo quasiparticles spin resonance (KQSR), has been defined as a 4f-ce strongly coupled ESR mode that behaves as a local probe of the Kondo quasiparticles in a quantum critical regime, Holanda et al 2011 Phys. Rev. Lett. 107 026402. Interestingly, β-YbAlB4 possesses a previously known structural variant, namely the α-YbAlB4, phase which is a paramagnetic Fermi liquid (FL) at low temperatures Macaluso et al 2007 Chem. Mater. 19 1918. However, it has been recently suggested that the α-YbAlB4 phase may be tuned to NFL behavior and/or magnetic ordering as the compound is doped with Fe. Here we report ESR studies on the α-Yb1-xFexAlB4 (0 ⩽ x ⩽ 0.50) series as well as on the reference compound α-LuAlB4. For all measured samples, the observed ESR signal behaves as a CESR in the entire temperature range (10 K ≲ T ≲ 300 K) in clear contrast with what has been observed for β-YbAlB4. This striking result indicates that the proximity to a quantum critical point is crucial to the occurrence of a KQSR signal.

  4. Optical characterization and evaluation of the laser properties of Yb(3+)-doped (La, Sr)(Al, Ta)O(3) single crystals.

    PubMed

    Zhao, Chengchun; Hang, Yin; He, Xiaoming; Zhang, Lianhan; Yin, Jigang; Hu, Pengchao; He, Mingzhu; Ma, En

    2011-03-30

    A Yb(3+)-doped mixed-perovskite single crystal (La, Sr)(Al, Ta)O(3) (LSAT) crystal is grown by the Czochralski method. The absorption spectrum, fluorescence spectrum and fluorescence lifetime of Yb(3+) ions have been investigated, and the spectroscopic parameters of Yb:LSAT have also been calculated. This crystal exhibits a remarkably large ground-state splitting (about 1100 cm(-1)), a relatively long fluorescence lifetime (0.85 ms) and broad absorption and emission bandwidths. The results indicate that the Yb(3+):LSAT crystal is a good candidate for diode-pumped ultrashort and tunable solid-state laser applications. © 2011 IOP Publishing Ltd

  5. Efficient OPSL-pumped mode-locked Yb:Lu2O3 laser with 67% optical-to-optical efficiency

    PubMed Central

    Heuer, Alexander M.; Saraceno, Clara J.; Beil, Kolja; Huber, Günter; Kränkel, Christian

    2016-01-01

    We present a mode-locked Yb:Lu2O3 laser with up to 67% of optical-to-optical efficiency. By utilizing a high brightness optically pumped semiconductor laser (OPSL) as a pump source and using a semiconductor saturable absorber mirror (SESAM) we obtained self-starting mode locking. A pulse duration of 571 fs at 4.73 W of average output power with an optical-to-optical efficiency of 67% was achieved. In a slightly different cavity configuration the pulse duration was reduced to 313 fs at 2.16 W of average output power. In both cases the pulse duration was longer than the Fourier limit and the spectrum supports significantly shorter pulse durations. The laser wavelength is centered at 1034 nm and the repetition rate is 100.76 MHz in both cases. In continuous wave fundamental mode operation the optical-to-optical efficiency was as high as 78% with output powers exceeding 5 W. PMID:26739546

  6. Efficient OPSL-pumped mode-locked Yb:Lu2O3 laser with 67% optical-to-optical efficiency

    NASA Astrophysics Data System (ADS)

    Heuer, Alexander M.; Saraceno, Clara J.; Beil, Kolja; Huber, Günter; Kränkel, Christian

    2016-01-01

    We present a mode-locked Yb:Lu2O3 laser with up to 67% of optical-to-optical efficiency. By utilizing a high brightness optically pumped semiconductor laser (OPSL) as a pump source and using a semiconductor saturable absorber mirror (SESAM) we obtained self-starting mode locking. A pulse duration of 571 fs at 4.73 W of average output power with an optical-to-optical efficiency of 67% was achieved. In a slightly different cavity configuration the pulse duration was reduced to 313 fs at 2.16 W of average output power. In both cases the pulse duration was longer than the Fourier limit and the spectrum supports significantly shorter pulse durations. The laser wavelength is centered at 1034 nm and the repetition rate is 100.76 MHz in both cases. In continuous wave fundamental mode operation the optical-to-optical efficiency was as high as 78% with output powers exceeding 5 W.

  7. Highly-efficient continuous-wave intra-cavity frequency-doubled Yb:LuAG thin-disk laser with 1 kW of output power.

    PubMed

    Dietrich, Tom; Piehler, Stefan; Rumpel, Martin; Villeval, Philippe; Lupinski, Dominique; Abdou-Ahmed, Marwan; Graf, Thomas

    2017-03-06

    We report on the generation of continuous-wave, intra-cavity frequency-doubled, multi-mode laser radiation in an Yb:LuAG thin-disk laser. Output powers of up to 1 kW at a wavelength of 515 nm were achieved at an unprecedented optical efficiency of 51.6% with respect to the pumping power of the thin-disk laser. The wavelength stabilization and spectral narrowing as well as the polarization selection, which is necessary for a stable and efficient second-harmonic generation, was achieved by the integration of a diffraction grating into the dielectric end mirror of the cavity, which exhibits a diffraction efficiency of 99.8%. At a frequency-doubled output power of 820 W the peak-to-valley power fluctuations measured during 100 minutes of laser operation amounted to only 8.2 W (1.0%). The beam parameter product of the frequency-doubled output was 3.4 mm·mrad (M2 ≈ 20), which is suitable for standard beam delivery using fibers with a core diameter of 100 µm and a NA of 0.2.

  8. Gamma induced atom displacements in LYSO and LuYAP crystals as used in medical imaging applications

    NASA Astrophysics Data System (ADS)

    Piñera, Ibrahin; Cruz, Carlos M.; Abreu, Yamiel; Leyva, Antonio; Van Espen, Piet; Díaz, Angelina; Cabal, Ana E.; Van Remortel, Nick

    2015-08-01

    The radiation damage, in terms of atom displacements, induced by gamma irradiation in LYSO and LuYAP crystals is presented. 44Sc, 22Na and 48V are used as gamma sources for this study. The energy of gammas from the electron-positron annihilation processes (511 keV) is also included in the study. The atom displacements distributions inside each material are calculated following the Monte Carlo assisted Classical Method introduced by the authors. This procedure also allows to study the atom displacements in-depth distributions inside each crystal. The atom displacements damage in LYSO crystals is found to be higher than in LuYAP crystals, mainly provoked by the displacements of silicon and oxygen atoms. But the difference between atom displacements produced in LYSO and LuYAP decreases when more energetic sources are used. On the other hand, the correlation between the atom displacements and energy deposition in-depth distributions is excellent. The atom displacements to energy deposition ratio is found to increases with more energetic photon sources. LYSO crystals are then more liable to the atom displacements damage than LuYAP crystals.

  9. Effect of Yb(3+) on the Crystal Structural Modification and Photoluminescence Properties of GGAG:Ce(3+).

    PubMed

    Luo, Zhao-Hua; Liu, Yong-Fu; Zhang, Chang-Hua; Zhang, Jian-Xin; Qin, Hai-Ming; Jiang, Hao-Chuan; Jiang, Jun

    2016-03-21

    Gadolinium gallium aluminum garnet (GGAG) is a very promising host for the highly efficient luminescence of Ce(3+) and shows potential in radiation detection applications. However, the thermodynamically metastable structure would be slanted against it from getting high transparency. To stabilize the crystal structure of GGAG, Yb(3+) ions were codoped at the Gd(3+) site. It is found that the decomposition of garnet was suppressed and the transparency of GGAG ceramic was evidently improved. Moreover, the photoluminescence of GGAG:Ce(3+),xYb(3+) with different Yb(3+) contents has been investigated. When the Ce(3+) ions were excited under 475 nm, a typical near-infrared region emission of Yb(3+) ions can be observed, where silicon solar cells have the strongest absorption. Basing on the lifetimes of Ce(3+) ions in the GGAG:Ce(3+),xYb(3+) sample, the transfer efficiency from Ce(3+) to Yb(3+) and the theoretical internal quantum efficiency can be calculated and reach up to 86% and 186%, respectively. This would make GGAG:Ce(3+),Yb(3+) a potential attractive downconversion candidate for improving the energy conversion efficiency of crystalline silicon (c-Si) solar cells.

  10. Near infrared quantum cutting of Na+ and Eu2+-Yb3+ couple activated SrF2 crystal

    NASA Astrophysics Data System (ADS)

    Yagoub, M. Y. A.; Swart, H. C.; Dhlamini, M. S.; Coetsee, E.

    2016-10-01

    Na+ and Eu2+-Yb3+ couple activated SrF2 phosphor powders were synthesized by the co-precipitation method. The structure and luminescence properties of the system were investigated. X-ray diffraction data indicated that a mixture of cubic SrF2 and NaYbF4 phases gradually formed with an increase in the Yb3+ ion doping concentration. Diffuse reflectance has been used to confirm the existence of europium in the divalent state. The possibility of quantum cutting in the Eu2+-Yb3+ ions co-doped SrF2 crystal was discussed. Energy transfer that occurred subsequently from Eu2+ to Yb3+ was followed by an intense near-infrared (NIR) (∼1000 nm) emission spectral range. Emission spectra and the fluorescence decay measurements have been utilized to demonstrate the cooperative energy transfer in the Eu2+-Yb3+ couple ions. The energy transfer was completed at high concentration and the Yb3+ ions emission's intensity was reduced as a result of concentration quenching. In addition from the photoluminescence data it was also evident that Na+ induced a significant change to the NIR emission.

  11. Dislocations in YbF3 doped BaF2 crystals

    NASA Astrophysics Data System (ADS)

    Cirlan, Florina; Buse, Gabriel; Nicoara, Irina

    2014-11-01

    Three concentrations of YbF3 -doped BaF2 crystals were grown using the conventional Bridgman method. Transparent colorless crystals were obtained in graphite crucible in vacuum (˜10-1 Pa) using a shaped graphite furnace. The crystals have been cooled to room temperature using an established procedure. In order to study the etch pits morphology and the dislocations density the etching method have been used. This method consists in immersing the cleaved sample in 2N HCl at 60°C for 2 minutes. Small etch pits are developed at the emergence points of the dislocations. The etch pits have triangular or hexagonal shapes, depending on the dopant concentration. The dislocations density depends on the dopant concentration.

  12. Yb-doped silica glass and photonic crystal fiber based on laser sintering technology

    NASA Astrophysics Data System (ADS)

    Zhang, Wei; Wu, Jiale; Zhou, Guiyao; Xia, Changming; Liu, Jiantao; Tian, Hongchun; Liang, Wanting; Hou, Zhiyun

    2016-03-01

    We demonstrate the fabricating method for Yb3+-doped silica glass and double-cladding large mode area photonic crystal fiber (LMA PCF) based on laser sintering technology combined with a liquid phase doping method. The doped material prepared shows the amorphous property and the hydroxyl content is approximately 40 ppm. The attenuation of the fabricated LMA PCF is 14.2 dB m-1 at 976 nm, and the lowest value is 0.25 dB m-1 at 1200 nm. The laser slope efficiency is up to 70.2%.

  13. Rare-Earth Triangular Lattice Spin Liquid: A Single-Crystal Study of YbMgGaO4.

    PubMed

    Li, Yuesheng; Chen, Gang; Tong, Wei; Pi, Li; Liu, Juanjuan; Yang, Zhaorong; Wang, Xiaoqun; Zhang, Qingming

    2015-10-16

    YbMgGaO4, a structurally perfect two-dimensional triangular lattice with an odd number of electrons per unit cell and spin-orbit entangled effective spin-1/2 local moments for the Yb(3+) ions, is likely to experimentally realize the quantum spin liquid ground state. We report the first experimental characterization of single-crystal YbMgGaO4 samples. Because of the spin-orbit entanglement, the interaction between the neighboring Yb(3+) moments depends on the bond orientations and is highly anisotropic in the spin space. We carry out thermodynamic and the electron spin resonance measurements to confirm the anisotropic nature of the spin interaction as well as to quantitatively determine the couplings. Our result is a first step towards the theoretical understanding of the possible quantum spin liquid ground state in this system and sheds new light on the search for quantum spin liquids in strong spin-orbit coupled insulators.

  14. Hydroxide flux synthesis and crystal structure of the ordered palladate, LuNaPd{sub 6}O{sub 8}

    SciTech Connect

    Mugavero III, Samuel J.; Smith, Mark D.; Loye, Hans-Conrad zur . E-mail: ZurLoye@mail.chem.sc.edu

    2006-11-15

    We report the single crystal structure of LuNaPd{sub 6}O{sub 8} grown from a sodium hydroxide flux. The utilization of a hydroxide flux has led to the preparation of the first ordered substitution of a lanthanide metal and an alkali metal on the A-site in a platinum group oxide and the first palladate to contain both a lanthanide metal and an alkali metal. The 1:1 ordered substitution of Lu{sup 3+} and Na{sup +} in place of the commonly observed divalent cation leads to slabs of LuO{sub 8} and NaO{sub 8} cubes bridged together by PdO{sub 4} square planes. The compound crystallizes in the cubic space group Pm-3 (no. 200) with a=5.72500(10) A and is structurally related to other cubic palladium oxides. - Graphical abstract: Unit cell of the ordered palladate, LuNaPd{sub 6}O{sub 8} viewed along the z-direction. The Pd{sup 2+} cations (grey) reside in a square planar coordination environment and bridge together the LuO{sub 8} (blue) and NaO{sub 8} (yellow) cubes.

  15. Up-conversion emission in KGd(WO 4 ) 2 single crystals triply-doped with Er 3+ /Yb 3+ /Tm 3+ , Tb 3+ /Yb 3+ /Tm 3+ and Pr 3+ /Yb 3+ /Tm 3+ ions

    NASA Astrophysics Data System (ADS)

    Kasprowicz, D.; Brik, M. G.; Majchrowski, A.; Michalski, E.; Głuchowski, P.

    2011-09-01

    Triply-doped single crystals KGd(WO 4) 2:Er 3+/Yb 3+/Tm 3+, KGd(WO 4) 2:Tb 3+/Yb 3+/Tm 3+ and KGd(WO 4) 2:Pr 3+/Yb 3+/Tm 3+ were grown by the Top Seeded Solution Growth (TSSG) method, with an aim of getting efficient up-converted multicolored luminescence, which subsequently can be used for generation of white light. Such an aim determined the choice of the triply doped compounds: excitation of the Yb 3+ ions in the infrared spectral region is followed by red, green and blue emission from other dopants. It was shown that all these systems exhibit multicolor up-conversion fluorescence under 980 nm laser irradiation. Detailed spectroscopic studies of their absorption and luminescence spectra were performed. From the analysis of the dependence of the intensity of fluorescence on the excitation power the conclusion was made about significant role played by the host's conduction band and other possible defects of the KGd(WO 4) 2 crystal lattice in the up-conversion processes.

  16. High-power Yb:YAG single-crystal fiber amplifiers for femtosecond lasers in cylindrical polarization.

    PubMed

    Lesparre, Fabien; Gomes, Jean Thomas; Délen, Xavier; Martial, Igor; Didierjean, Julien; Pallmann, Wolfgang; Resan, Bojan; Eckerle, Michael; Graf, Thomas; Abdou Ahmed, Marwan; Druon, Frederic; Balembois, François; Georges, Patrick

    2015-06-01

    We demonstrate a three-stage diode-pumped Yb:YAG single-crystal-fiber amplifier to generate femtosecond pulses at high average powers with linear or cylindrical (i.e., radial or azimuthal) polarization. At a repetition rate of 20 MHz, 750-fs pulses were obtained at an average power of 85 W in cylindrical polarization and at 100 W in linear polarization. The report includes investigations on the use of Yb:YAG single-crystal fibers with different length/doping ratio and the zero-phonon pumping at a wavelength of 969 nm in order to optimize the performance.

  17. Scintillation characterizations of Tl 2 LiLuCl 6 : Ce 3+ single crystal

    NASA Astrophysics Data System (ADS)

    Rooh, Gul; Kim, H. J.; Jang, Jonghun; Kim, Sunghwan

    2017-07-01

    0.5%, 1%, 3% and 5% Ce-concentration single crystals of Tl2LiLuCl6 were grown from the melt using two zone vertical Bridgman technique. X-ray induced emission spectra showed Ce3+ emission between 370 nm and 540 nm wavelength range. Energy resolution, light yield and decay time of the grown samples were measured under {\\gamma}-ray excitation at room temperature. Energy resolution of 5.6% (FWHM) with 27,000+-2700 light yield is found for 1%Ce doped sample. For the same dopant concentration, three decay time components are also observed. Variation of scintillation properties is observed as a function of dopant concentration in this material.This material will provide excellent detection efficiency for X- and {\\gamma}-rays due to its high effective Z-number and density. It is expected that this scintillor will be a potential detector for the medical imaging techniques.

  18. Investigation on the structure and upconversion fluorescence of Yb3+/Ho3+ co-doped fluorapatite crystals for potential biomedical applications

    PubMed Central

    Li, Xiyu; Zhu, Jingxian; Man, Zhentao; Ao, Yingfang; Chen, Haifeng

    2014-01-01

    Rare-earth Yb3+ and Ho3+ co-doped fluorapatite (FA:Yb3+/Ho3+) crystals were prepared by hydrothermal synthesis, and their structure, upconversion properties, cell proliferation and imaging were investigated. The synthesized crystals, with a size of 16 by 286 nm, have a hexagonal crystal structure of classic FA and a Ca/Yb/Ho molar ratio of 100/16/2.1. Several reasonable Yb3+/Ho3+ -embedding lattice models along the fluorine channel of the FA crystal cell are proposed for the first time, such as models for (Ca7YbHo©)(PO4)6F2 and (Ca6YbHoNa2)(PO4)6F2. The activated FA:Yb3+/Ho3+ crystals were found to exhibit distinct upconversion fluorescence. The 543- and 654-nm signals in the emission spectra could be assigned, respectively, to the 5F4 (5S2) - 5I8 and 5F5 - 5I8 transitions of holmium via 980-nm near-infrared excitation and the energy transfer of ytterbium. After the surfaces were grafted with hydrophilic dextran, the crystals displayed clear fluorescent cell imaging. Thus, the prepared novel FA:Yb3+/Ho3+ upconversion fluorescent crystals have potential applications in the biomedical field. PMID:24658285

  19. Growth of (Er,Yb):YAl{sub 3}(BO{sub 3}){sub 4} laser crystals

    SciTech Connect

    Pilipenko, O. V. Mal'tsev, V. V.; Koporulina, E. V.; Leonyuk, N. I.; Tolstik, N. A.; Kuleshov, N. V.

    2008-03-15

    (Er,Yb):YAl{sub 3}(BO{sub 3}){sub 4} single crystals of optical quality, up to 15 Multiplication-Sign 10 Multiplication-Sign 10 mm{sup 3} in size, have been grown from a (Er{sub 0.023}Yb{sub 0.116}Y{sub 0.862})Al{sub 3}(BO{sub 3}){sub 4} solution in a Y{sub 2}O{sub 3}-B{sub 2}O{sub 3}-K{sub 2}Mo{sub 3}O{sub 10} melt. The initial borate concentration was 17 wt %, and the flux cooling rate increased from 0.08 to 0.12 Degree-Sign C/h in the range 1060-1000 Degree-Sign C. The physical properties of the single crystals grown are good enough that they can be used as laser elements in systems with diode pumping and radiation near 1.5 {mu}m.

  20. Neutron capture cross sections and solar abundances of /sup 160,161/Dy, /sup 170,171/Yb, /sup 175,176/Lu, and /sup 176,177/Hf have been measured

    SciTech Connect

    Beer, H.; Walter, G.; Macklin, R.L.; Patchett, P.J.

    1984-08-01

    The neutron capture cross sections and solar abundances of /sup 160,161/Dy, /sup 170,171/Yb, /sup 175,176/Lu, and /sup 176,177/Hf have been measured. With this data base s-process studies have been carried out to determine the s-process neutron density and temperature and to investigate the s-process nucleosynthesis of the /sup 176/Lu clock. From various branchings the neutron density was found to be (0.8--1.8) x 10/sup 8/ neutrons per cm/sup 3/ and the temperature kT to be 18--28 keV. On the basis of the present data, /sup 176/Lu proved not to be applicable as a cosmic clock because of the temperature sensitivity of the /sup 176/Lu half-life but can be used instead as a stellar thermometer. Constraints for the s-process temperature (kT = 20--28 keV) were found to be in good agreement with the investigated branchings.

  1. Laser-induced cooling of a Yb:YAG crystal in air at atmospheric pressure.

    PubMed

    Soares de Lima Filho, Elton; Nemova, Galina; Loranger, Sébastien; Kashyap, Raman

    2013-10-21

    We report for the first time the experimental demonstration of optical cooling of a bulk crystal at atmospheric pressure. The use of a fiber Bragg grating (FBG) sensor to measure laser-induced cooling in real time is also demonstrated for the first time. A temperature drop of 8.8 K from the chamber temperature was observed in a Yb:YAG crystal in air when pumped with 4.2 W at 1029 nm. A background absorption of 2.9 × 10⁻⁴ cm⁻¹ was estimated with a pump wavelength at 1550 nm. Simulations predict further cooling if the pump power is optimized for the sample's dimensions.

  2. Anisotropic laser properties of Yb:Ca3La2(BO3)4 disordered crystal

    NASA Astrophysics Data System (ADS)

    Wang, Lisha; Xu, Honghao; Pan, Zhongben; Han, Wenjuan; Chen, Xiaowen; Liu, Junhai; Yu, Haohai; Zhang, Huaijin

    2016-08-01

    A study is carried out experimentally on the anisotropy in the laser action of Yb:Ca3La2(BO3)4 disordered crystal, demonstrated with the output coupling changed over a wide range from 0.5% to 40%. Complex polarization state variation with output coupling and evolution with pump power are observed in the laser operation achieved with a- and c-cut crystal samples. A maximum output power of 8.2 W is produced at wavelengths around 1043 nm, with an incident pump power of 24.9 W, the optical-to-optical efficiency being 33%. The polarized absorption and emission cross section spectra are also presented.

  3. Crystal structure of the high-temperature modification of ytterbium perrhenate Yb(ReO{sub 4}){sub 3}

    SciTech Connect

    Khrustalev, V.N.; Varfolomeev, M.B.; Shamrai, N.B.; Struchkov, Yu.T.; Pisarevskii, A.P. |

    1993-11-01

    Yb(ReO{sub 4}){sub 3} obtained by the slow crystallization of its melt in air is investigated by X-ray diffraction (298 K, 329 reflections, R = 0.083, R{sub w} = 0.102). Crystals are hexagonal, a = 9.999(4) {angstrom}, c = 6.070(2) {angstrom}, Z = 2, space group P6{sub 3}/m. The structure is related to the CdTh(MoO{sub 4}){sub 3} type and consists of columns of Yb polyhedra (three-cap trigonal prisms) and of Re tetrahedra. The correlation of the structures of Yb(ReO{sub 4}){sub 3} and apatite is discussed.

  4. Temperature dependence of the crystal structure and charge ordering in Yb{sub 4}As{sub 3}

    SciTech Connect

    Staub, U.; Shi, M.; Schulze-Briese, C.; Patterson, B.D.; Fauth, F.; Dooryhee, E.; Soderholm, L.; Cross, J.O.; Mannix, D.; Ochiai, A.

    2005-02-15

    Resonant and nonresonant x-ray scattering, combined with x-ray absorption data, are presented on Yb{sub 4}As{sub 3}. The nonresonant data allow a detailed determination of the low-temperature crystal structure and its evolution as a function of temperature. Bond-valence-sum calculations are performed and compared with theoretical predictions. Using the structural knowledge, the energy dependence, near the Yb L{sub 3} edge, of particular x-ray reflections are calculated and compared with experiment, and the temperature dependence of the charge order is extracted. A united picture of the temperature-dependent crystal structure and charge ordering in Yb{sub 4}As{sub 3} emerges and is compared with theory.

  5. Laser performance of in-band pumped Er : LiYF4 and Er : LiLuF4 crystals

    NASA Astrophysics Data System (ADS)

    Gorbachenya, K. N.; Kurilchik, S. V.; Kisel, V. E.; Yasukevich, A. S.; Kuleshov, N. V.; Nizamutdinov, A. S.; Korableva, S. L.; Semashko, V. V.

    2016-02-01

    Spectroscopic properties of Er : LiLuF4 and Er : LiYF4 crystals in the spectral region near 1.5 μm and the lasing characteristics of these crystals under in-band pumping at a wavelength of 1522 nm are studied. With the Er : LiLuF4 crystal, the maximum slope efficiency with respect to the absorbed pump power was 44% at a wavelength of 1609 nm. Continuous-wave operation of an inband pumped Er : LiYF4 laser is obtained for the first time. The output power at a wavelength of 1606 nm was 58 mW with a slope efficiency of 21%.

  6. Electric polarization observed in single crystals of multiferroic Lu2MnCoO6

    DOE PAGES

    Chikara, Shalinee; Singleton, John; Bowlan, John M.; ...

    2016-05-17

    We report electric polarization and magnetization measurements in single crystals of double perovskite Lu2MnCoO6 using pulsed magnetic fields and optical second harmonic generation in dc magnetic fields. We observe well-resolved magnetic field-induced changes in the electric polarization in single crystals and thereby resolve the question about whether multiferroic behavior is intrinsic to these materials or is an extrinsic feature of polycrystals. We find electric polarization along the crystalline b axis, that is suppressed by applying a magnetic fields along the c axis, and advance a model for the origin of magnetoelectric coupling. We furthermore map the phase diagram using bothmore » capacitance and electric polarization to identify regions of ordering and regions of magnetoelectric hysteresis. This compound is a rare example of coupled hysteretic behavior in the magnetic and electric properties. Furthermore, the ferromagneticlike magnetic hysteresis loop that couples to hysteretic electric polarization can be attributed not to ordinary ferromagnetic domains, but to the rich physics of magnetic frustration of Ising-like spins in the axial next-nearest-neighbor interaction model.« less

  7. Electric polarization observed in single crystals of multiferroic Lu2MnCoO6

    NASA Astrophysics Data System (ADS)

    Chikara, S.; Singleton, J.; Bowlan, J.; Yarotski, D. A.; Lee, N.; Choi, H. Y.; Choi, Y. J.; Zapf, V. S.

    2016-05-01

    We report electric polarization and magnetization measurements in single crystals of double perovskite Lu2Mn Co O6 using pulsed magnetic fields and optical second harmonic generation in dc magnetic fields. We observe well-resolved magnetic field-induced changes in the electric polarization in single crystals and thereby resolve the question about whether multiferroic behavior is intrinsic to these materials or is an extrinsic feature of polycrystals. We find electric polarization along the crystalline b axis, that is suppressed by applying a magnetic fields along the c axis, and advance a model for the origin of magnetoelectric coupling. We furthermore map the phase diagram using both capacitance and electric polarization to identify regions of ordering and regions of magnetoelectric hysteresis. This compound is a rare example of coupled hysteretic behavior in the magnetic and electric properties. The ferromagneticlike magnetic hysteresis loop that couples to hysteretic electric polarization can be attributed not to ordinary ferromagnetic domains, but to the rich physics of magnetic frustration of Ising-like spins in the axial next-nearest-neighbor interaction model.

  8. Possible undercompensation effect in the Kondo insulator (Yb,Tm)B12

    NASA Astrophysics Data System (ADS)

    Alekseev, P. A.; Nemkovski, K. S.; Mignot, J.-M.; Clementyev, E. S.; Ivanov, A. S.; Rols, S.; Bewley, R. I.; Filipov, V. B.; Shitsevalova, N. Yu.

    2014-03-01

    The effects of Tm substitution on the dynamical magnetic response of Yb1-xTmxB12 (x=0, 0.08, 0.15, and 0.75) and Lu0.92Tm0.08B12 compounds have been studied using time-of-flight inelastic neutron scattering. Major changes were observed in the spectral structure and temperature evolution of the Yb contribution to the inelastic response for a rather low content of magnetic Tm ions. A sizable influence of the RB12 host (YbB12, as compared to LuB12 or pure TmB12) on the crystal-field splitting of the Tm3+ ion is also reported. The results point to a specific effect of impurities carrying a magnetic moment (Tm, as compared to Lu or Zr) in a Kondo insulator, which is thought to reflect the "undercompensation" of Yb magnetic moments, originally Kondo screened in pure YbB12. A parallel is made with the strong effect of Tm substitution on the temperature dependence of the Seebeck coefficient in Yb1-xTmxB12, which was reported previously.

  9. From optical spectroscopy to a concentration quenching model and a theoretical approach to laser optimization for Yb3+-doped YLiF4 crystals

    NASA Astrophysics Data System (ADS)

    Boulon, G.; Guyot, Y.; Ito, M.; Bensalah, A.; Goutaudier, C.; Panczer, G.; Gâcon, J. C.

    2004-01-01

    A spectroscopic characterization was carried out to identify crystal-field levels for magnetic-dipole transitions of Yb3+ ions located in the Y3+ dodecahedral S4 crystallographic site in YLiF4 (YLF) crystals which were grown either by the Czochralski technique or by the laser heated pedestal growth (LHPG) technique. The concentration dependence of the measured decay time of the 2F5/2 excited level of Yb3+ was analysed in order to understand relevant concentration quenching mechanisms. Under Yb3+ ion infrared pumping, self-trapping and up-conversion non-radiative energy transfer to trace rare-earth impurities (Er3+, Tm3+) has been observed over the visible region and interpreted by a limited-diffusion process within the Yb3+ doping ion subsystem to the impurities. The principal parameters useful for a theoretical approach for potential laser applications of Yb3+-doped YLiF4 crystals have also been given.

  10. Single-crystal growth and physical property characterization of the intermediate-valence compound YbFe2Al10

    NASA Astrophysics Data System (ADS)

    Lv, J. L.; Chen, R. Y.; Wang, H. P.; Luo, J. L.; Wang, N. L.

    2017-06-01

    We report single-crystal growth and physical property characterization of YbFe2Al10 compounds. The measurements of resistivity, magnetic susceptibility, and specific heat show different behaviors from previous studies on polycrystalline samples. An intermediate-valence characteristic with moderate mass enhancement is indicated. In particular, the optical spectroscopy measurement reveals formation of multiple hybridization energy gaps which become progressively pronounced at low temperature. The multiple hybridization energy gaps are likely caused by the hybridizations between the flat band from Yb 4 f electrons and different bands of conduction electrons.

  11. Preparation and photoluminescence properties of RE:Na 3La 9O 3(BO 3) 8 ( RE=Er, Yb) crystals

    NASA Astrophysics Data System (ADS)

    Liu, Zuoliang; Zhang, Guochun; Zhang, Jianxiu; Bai, Xiaoyan; Fu, Peizhen; Wu, Yicheng

    2010-06-01

    Using Na 2CO 3-H 3BO 3-NaF as fluxes, transparent RE:Na 3La 9O 3(BO 3) 8 (abbr. RE:NLBO, RE=Er, Yb) crystals have been grown by the top seed solution growth (TSSG) method. The X-ray powder diffraction analysis shows that the RE:NLBO crystals have the same structure with NLBO. The element contents were determined by molar to be 0.64% Er 3+ in Er:NLBO, 2.70% Yb 3+ in Yb:NLBO, respectively. The polarized absorption spectra of RE:NLBO have been measured at room temperature and show that both Er:NLBO and Yb:NLBO have a strong absorption bands near 980 nm with wide FWHM (Full Wave at Half Maximum) (21 nm for Er:NLBO and 25 nm for Yb:NLBO). Fluorescence spectra have been recorded. Yb:NLBO has the emission peaks at 985 nm, 1028 nm and 1079 nm and the emission peak of Er:NLBO is at 1536 nm. Spectral parameters have been calculated by the Judd-Ofelt theory for Er:NLBO and the reciprocity method for Yb:NLBO, respectively. The calculated values show that Er:NLBO is a candidate of 1.55 μm laser crystals and Yb:NLBO is a candidate for self-frequency doubling crystal.

  12. Transition from semiconducting to metallic-like conducting and weak antilocalization effect in single crystals of LuPtSb

    SciTech Connect

    Hou, Zhipeng; Wang, Yue; Xu, Guizhou; Zhang, Xiaoming; Liu, Enke; Xi, Xuekui; Wang, Wenhong Wu, Guangheng; Wang, Wenquan; Liu, Zhongyuan

    2015-03-09

    High quality half-Heusler single crystals of LuPtSb have been synthesized by a Pb flux method. The temperature dependent resistivity and Hall effects indicate that the LuPtSb crystal is a p-type gapless semiconductor showing a transition from semiconducting to metallic conducting at 150 K. Moreover, a weakly temperature-dependent positive magnetoresistance (MR) as large as 109% and high carrier mobility up to 2950 cm{sup 2}/V s are experimentally observed at temperatures below 150 K. The low-field MR data show evidence for weak antilocalization (WAL) effect at temperatures even up to 150 K. Analysis of the temperature and angle dependent magnetoconductance manifests that the WAL effect originates from the bulk contribution owing to the strong spin-orbital coupling.

  13. Nonequivalent Yb{sup 3+} centres in Y{sub 1-x}Yb{sub x}Al{sub 3}(BO{sub 3}){sub 4} laser crystals

    SciTech Connect

    Boldyrev, K N; Popova, Marina N; Bezmaternykh, L N; Betinelli, M

    2011-02-28

    The absorption spectra of nonlinear laser crystals Y{sub 1-x}Yb{sub x}Al{sub 3}(BO{sub 3}){sub 4} grown from bismuth-lithium-molybdate and potassium-molybdate solution-melts are comparatively studied by high-resolution Fourier spectroscopy. The differences observed in the fine structure of the absorption spectra are correlated with the variations in the solution-melt composition and in the concentrations of bismuth and molybdenum impurities in the crystals. It is shown that the concentration of the molybdenum impurity (the main factor hindering lasing in the UV spectral region) in the single crystals grown from the bismuth-lithium-molybdate solutions is more than an order of magnitude smaller than in the crystals grown using the potassium-molybdate solution-melt. The described method can be used for express analysis of the quality of UV laser crystals and for improving the solution-melt technologies of growth of laser crystals and crystals used for generation of the fourth harmonic of Nd:YAG laser radiation. (active media)

  14. Yb3+-doped YVO4 crystal for efficient Kerr-lens mode locking in solid-state lasers.

    PubMed

    Lagatsky, A A; Sarmani, A R; Brown, C T A; Sibbett, W; Kisel, V E; Selivanov, A G; Denisov, I A; Troshin, A E; Yumashev, K V; Kuleshov, N V; Matrosov, V N; Matrosova, T A; Kupchenko, M I

    2005-12-01

    We report the first demonstration, to our knowledge, of soft-aperture Kerr-lens mode locking in a diode-pumped femtosecond Yb3+:YVO4 laser. Near-transform-limited pulses as short as 61 fs are generated around a center wavelength of 1050 nm with an output power of 54 mW and a pulse repetition frequency of 104.5 MHz. This is, to our knowledge, the shortest pulse generated directly from an Yb laser having a crystalline host material. The femtosecond operation has a mode-locking threshold at an absorbed pump power of 190 mW. The nonlinear refractive indexes of the Yb3+:YVO4 crystal have been measured to be 19 x 10(-16) cm2/W and 15 x 10(-16) cm2/W for the sigma and pi polarizations, respectively, at 1080 nm.

  15. Spectroscopic, diode-pumped laser properties and gamma irradiation effect on Yb, Er, Ho:GYSGG crystals.

    PubMed

    Chen, Jiakang; Sun, Dunlu; Luo, Jianqiao; Xiao, Jingzhong; Kang, Hongxiang; Zhang, Huili; Cheng, Maojie; Zhang, Qingli; Yin, Shaotang

    2013-04-15

    We demonstrate a diode end-pumped Yb, Er, Ho:Gd(1.17)Y(1.83)Sc(2)Ga(3)O(12) (GYSGG) laser operated at 2.79 μm in continuous-wave mode. Spectral analysis shows that Yb(3+) and Ho(3+) act as sensitizer and deactivator ions, respectively. Pumping with a 967 nm laser diode produces the maximum output power of 411 mW, corresponding to optical-optical conversion and slope efficiencies of 11.6% and 13.1%, respectively. The minimum laser threshold is only 81 mW because of Ho(3+) doping. The laser properties are only slightly influenced by 100 mrad gamma irradiation. The Yb, Er, Ho:GYSGG crystal possesses excellent radiation resistance and is a potential laser gain medium in radiant environments.

  16. Neutron spectroscopic study of Crystal-field excitation in Yb2 (Ti2 - x Ybx) O7 -x/2

    NASA Astrophysics Data System (ADS)

    Gaudet, Jonathan; Maharaj, Dalini; Kermarrec, Edwin; Granroth, Garrett; Ross, Kate; Dabowska, Hanna; Gaulin, Bruce

    2015-03-01

    Among the rare-earth titanate pyrochlores, Yb2 Ti2O7 has attracted much attention as a potential realization of a quantum spin ice. While strong quantum effects are absent in classical spin ice compounds, they are thought to be significant in Yb2 Ti2O7 because of its effective spin S=1/2 and its XY spin anisotropy, quantities both determined by the Crystal-Electric Field (CEF) levels. However, a thorough neutron spectroscopy study of the CEF levels is still lacking. Here, we report time-of-flight inelastic neutron scattering measurements on Yb2 Ti2O7 . Our results lead to the unambiguous determination of the CEF levels, the ground-state wavefunction and therefore the nature of the spin anisotropy of the J=7/2 Yb3+ . A significant sample dependence in the low temperature heat capacity has been reported and attributed to an excess of Yb3+ (''stuffing'') in the structure. Our measurements, carried out on two well-characterized samples with different levels of stuffing, allow us to discuss the impact of such disorder on the CEF levels.

  17. Broadband near ultra violet sensitization of 1 μm luminescence in Yb3+-doped CeO2 crystal

    NASA Astrophysics Data System (ADS)

    Ueda, Jumpei; Tanabe, Setsuhisa

    2011-10-01

    Broadband spectral modification of near ultra violet (UV) light to infra-red (IR) light is investigated in Yb3+-doped CeO2 polycrystalline ceramics sintered in different atmospheres (air, oxygen, and 95%N2-5%H2). The intense Yb3+ photoluminescence (PL) peaked at 970 nm was observed by the UV excitation at around 390 nm in the samples except those sintered under N2-H2. A broad photoluminescence excitation (PLE) band of Yb3+ luminescence peaked at 390 nm corresponds to the absorption band and the photocurrent excitation band in the non-doped CeO2 crystal, which are also in accordance with the PLE band of Eu3+ luminescence in the Eu3+-doped CeO2. Judging from these results, the PLE band is attributed to the charge transfer (CT) band from O2- to Ce4+, but not to the CT from O2- to Yb3+. From the sintering atmosphere dependence of the PL and PLE, we found that the oxygen vacancies and Ce3+ impurities are not responsible for the 390 nm-absorption band but they work as a quenching center for the Yb3+ luminescence.

  18. Low-temperature superstructures of a series of Cd6M (M = Ca, Y, Sr, Pr, Nd, Sm, Gd, Tb, Dy, Ho, Er, Tm, Yb and Lu) crystalline approximants.

    PubMed

    Nishimoto, Kazue; Sato, Takeru; Tamura, Ryuji

    2013-06-12

    The low-temperature (LT) superstructure and the phase transition temperature have been investigated for a series of Cd6M crystalline approximants by transmission electron microscopy as well as electrical resistivity measurements. Except for M = Lu, Cd6M is found to undergo a phase transition to a monoclinic phase at a low temperature and the transition temperature (Tc) scales well with the size of the M atom. For M = Ca, Y, Pr, Nd, Sm, Gd, Tb, Dy, Ho, Er and Tm the LT superstructure is explained by a √2a × a × √2a lattice with the space group C2/c, and for M = Sr and Yb a √2a × 2a × √2a monoclinic lattice with P2/m. On the other hand, no phase transition is observed for M = Lu, indicating that a Cd4 tetrahedron at the cluster center remains disordered down to the lowest temperature, i.e. 16 K. It is shown that the volume inside the Cd20 dodecahedron plays a crucial role in the occurrence of the phase transition, and long-term aging in particular promotes the phase transition for late rare-earth elements such as Ho, Er and Tm, suggesting that the transition is sensitive to and is even hindered by disorder such as atomic vacancies. The absence of the transition for M = Lu is attributed to the highest activation energy for the transition due to the smallest volume inside the Cd20 dodecahedron.

  19. Crystal growth by Bridgman and Czochralski method of the ferromagnetic quantum critical material YbNi4P2

    NASA Astrophysics Data System (ADS)

    Kliemt, K.; Krellner, C.

    2016-09-01

    The tetragonal YbNi4P2 is one of the rare examples of compounds that allow the investigation of a ferromagnetic quantum critical point. We report in detail on two different methods which have been used to grow YbNi4P2 single crystals from a self-flux. The first, a modified Bridgman method, using a closed crucible system yields needle-shaped single crystals oriented along the [001]-direction. The second method, the Czochralski growth from a levitating melt, yields large single crystals which can be cut in any desired orientation. With this crucible-free method, samples without flux inclusions and a resistivity ratio at 1.8 K of RR1.8K = 17 have been grown.

  20. Fabrication and laser performance of Yb3+/Al3+ co-doped photonic crystal fiber synthesized by plasma nonchemical vapor deposition method

    NASA Astrophysics Data System (ADS)

    Xia, Changming; Zhou, Guiyao; Liu, Jiantao; Wang, Chao; Han, Ying; Zhang, Wei; Yuan, Jinhui

    2015-10-01

    In this paper, the bulk Yb3+/Al3+ co-doped silica glass with 1.3 Yb2O3-2.5Al2O3-96.2SiO2 (wt%) are synthesized by plasma nonchemical vapor deposition method combining solution doping technology, where the inductively coupled plasma is used as the heat source. The influence of different O2/N2 ratios on the fluorescence properties of Yb3+/Al3+ co-doped silica glass are investigated. The large mode area photonic crystal fiber (PCF) is fabricated by using the bulk Yb3+/Al3+ co-doped silica glass as fiber core. The laser performance of Yb3+/Al3+ co-doped photonic crystal fiber is studied.

  1. Growth and Spectral Assessment of Yb3+-Doped KBaGd(MoO4)3 Crystal: A Candidate for Ultrashort Pulse and Tunable Lasers

    PubMed Central

    Yu, Yi; Huang, Yisheng; Zhang, Lizhen; Lin, Zhoubin; Wang, Guofu

    2013-01-01

    In order to explore new more powerful ultrashort pulse laser and tunable laser for diode-pumping, this paper reports the growth and spectral assessment of Yb3+-doped KBaGd(MoO4)3 crystal. An Yb3+:KBaGd(MoO4)3 crystal with dimensions of 50×40×9 mm3 was grown by the TSSG method from the K2Mo2O7 flux. The investigated spectral properties indicated that Yb3+:KBaGd(MoO4)3 crystal exhibits broad absorption and emission bands, except the large emission and gain cross-sections. This feature of the broad absorption and emission bands is not only suitable for the diode pumping, but also for the production of ultrashort pulses and tunability. Therefore, Yb3+:KBaGd(MoO4)3 crystal can be regarded as a candidate for the ultrashort pulse and tunable lasers. PMID:23349892

  2. Growth and spectral assessment of Yb(3+)-doped KBaGd(MoO4)3 crystal: a candidate for ultrashort pulse and tunable lasers.

    PubMed

    Yu, Yi; Huang, Yisheng; Zhang, Lizhen; Lin, Zhoubin; Wang, Guofu

    2013-01-01

    In order to explore new more powerful ultrashort pulse laser and tunable laser for diode-pumping, this paper reports the growth and spectral assessment of Yb(3+)-doped KBaGd(MoO(4))(3) crystal. An Yb(3+):KBaGd(MoO(4))(3) crystal with dimensions of 50×40×9 mm(3) was grown by the TSSG method from the K(2)Mo(2)O(7) flux. The investigated spectral properties indicated that Yb(3+):KBaGd(MoO(4))(3) crystal exhibits broad absorption and emission bands, except the large emission and gain cross-sections. This feature of the broad absorption and emission bands is not only suitable for the diode pumping, but also for the production of ultrashort pulses and tunability. Therefore, Yb(3+):KBaGd(MoO(4))(3) crystal can be regarded as a candidate for the ultrashort pulse and tunable lasers.

  3. High-gain polymer optical waveguide amplifiers based on core-shell NaYF4/NaLuF4: Yb(3+), Er(3+) NPs-PMMA covalent-linking nanocomposites.

    PubMed

    Zhang, Meiling; Zhang, Weiwei; Wang, Fei; Zhao, Dan; Qu, Chunyang; Wang, Xibin; Yi, Yunji; Cassan, Eric; Zhang, Daming

    2016-11-09

    Waveguide amplifiers have always been significant key components for optical communication. Unfortunately, the low concentration of rare earth ions doped in the host material and the inadequate optimization of the waveguide structure have been the common bottleneck limitations. Here, a novel material, NaYF4/NaLuF4: 20% Yb(3+), 2% Er(3+) nanoparticle-Polymeric Methyl Methacrylate covalent-linking nanocomposite, was synthesized. The concentrations of Er(3+) and Yb(3+) doping increased an order of magnitude. Under a 980 nm laser excitation, highly efficient emission at 1.53 μm was obtained. The characteristic parameters of the single mode waveguide were carefully designed and optimized by using a finite difference method. A formulized iteration method is presented for solving the rate equations and the propagation equations of the EYCDWA, and both the steady state behavior and the gain were numerically simulated. The optimal Er(3+) and Yb(3+) concentrations are 2.8 × 10(26) m(-3) and 2.8 × 10(27) m(-3), and the optimal waveguide length is 1.3 cm. Both theoretical and experimental results indicated that, for an input signal power of 0.1 mW and a pump power of 400 mW, a net gain of 15.1 dB at 1530 nm is demonstrated. This result is the highest gain ever reported in polymer-based waveguide amplifiers doped with inorganic Er(3+)-Yb(3+) codoped nanocrystals.

  4. High-gain polymer optical waveguide amplifiers based on core-shell NaYF4/NaLuF4: Yb3+, Er3+ NPs-PMMA covalent-linking nanocomposites

    NASA Astrophysics Data System (ADS)

    Zhang, Meiling; Zhang, Weiwei; Wang, Fei; Zhao, Dan; Qu, Chunyang; Wang, Xibin; Yi, Yunji; Cassan, Eric; Zhang, Daming

    2016-11-01

    Waveguide amplifiers have always been significant key components for optical communication. Unfortunately, the low concentration of rare earth ions doped in the host material and the inadequate optimization of the waveguide structure have been the common bottleneck limitations. Here, a novel material, NaYF4/NaLuF4: 20% Yb3+, 2% Er3+ nanoparticle-Polymeric Methyl Methacrylate covalent-linking nanocomposite, was synthesized. The concentrations of Er3+ and Yb3+ doping increased an order of magnitude. Under a 980 nm laser excitation, highly efficient emission at 1.53 μm was obtained. The characteristic parameters of the single mode waveguide were carefully designed and optimized by using a finite difference method. A formulized iteration method is presented for solving the rate equations and the propagation equations of the EYCDWA, and both the steady state behavior and the gain were numerically simulated. The optimal Er3+ and Yb3+ concentrations are 2.8 × 1026 m‑3 and 2.8 × 1027 m‑3, and the optimal waveguide length is 1.3 cm. Both theoretical and experimental results indicated that, for an input signal power of 0.1 mW and a pump power of 400 mW, a net gain of 15.1 dB at 1530 nm is demonstrated. This result is the highest gain ever reported in polymer-based waveguide amplifiers doped with inorganic Er3+-Yb3+ codoped nanocrystals.

  5. Effect of interface on epitaxy and magnetism in h-RFeO3/Fe3O4/Al2O3 films (R  =  Lu, Yb)

    NASA Astrophysics Data System (ADS)

    Zhang, Xiaozhe; Yin, Yuewei; Yang, Sen; Yang, Zhimao; Xu, Xiaoshan

    2017-04-01

    We have carried out the growth of h-RFeO3 (0 0 1) (R  =  Lu, Yb) thin films on Fe3O4 (1 1 1)/Al2O3 (0 0 1) substrates, and studied the effect of the h-RFeO3 (0 0 1)/Fe3O4 (1 1 1) interfaces on the epitaxy and magnetism. The observed epitaxial relations between h-RFeO3 and Fe3O4 indicate an unusual matching of Fe sub-lattices rather than a matching of O sub-lattices. The out-of-plane direction was found to be the easy magnetic axis for h-YbFeO3 (0 0 1) but the hard axis for Fe3O4 (1 1 1) in the h-YbFeO3 (0 0 1)/Fe3O4 (1 1 1)/Al2O3 (0 0 1) films, suggesting a perpendicular magnetic alignment at the h-YbFeO3 (0 0 1)/Fe3O4 (1 1 1) interface. These results indicate that Fe3O4 (1 1 1)/Al2O3 (0 0 1) could be a promising substrate for epitaxial growth of h-RFeO3 films of well-defined interface and for exploiting their spintronic properties.

  6. High-gain polymer optical waveguide amplifiers based on core-shell NaYF4/NaLuF4: Yb3+, Er3+ NPs-PMMA covalent-linking nanocomposites

    PubMed Central

    Zhang, Meiling; Zhang, Weiwei; Wang, Fei; Zhao, Dan; Qu, Chunyang; Wang, Xibin; Yi, Yunji; Cassan, Eric; Zhang, Daming

    2016-01-01

    Waveguide amplifiers have always been significant key components for optical communication. Unfortunately, the low concentration of rare earth ions doped in the host material and the inadequate optimization of the waveguide structure have been the common bottleneck limitations. Here, a novel material, NaYF4/NaLuF4: 20% Yb3+, 2% Er3+ nanoparticle-Polymeric Methyl Methacrylate covalent-linking nanocomposite, was synthesized. The concentrations of Er3+ and Yb3+ doping increased an order of magnitude. Under a 980 nm laser excitation, highly efficient emission at 1.53 μm was obtained. The characteristic parameters of the single mode waveguide were carefully designed and optimized by using a finite difference method. A formulized iteration method is presented for solving the rate equations and the propagation equations of the EYCDWA, and both the steady state behavior and the gain were numerically simulated. The optimal Er3+ and Yb3+ concentrations are 2.8 × 1026 m−3 and 2.8 × 1027 m−3, and the optimal waveguide length is 1.3 cm. Both theoretical and experimental results indicated that, for an input signal power of 0.1 mW and a pump power of 400 mW, a net gain of 15.1 dB at 1530 nm is demonstrated. This result is the highest gain ever reported in polymer-based waveguide amplifiers doped with inorganic Er3+-Yb3+ codoped nanocrystals. PMID:27827414

  7. Effect of interface on epitaxy and magnetism in h-RFeO3/Fe3O4/Al2O3 films (R  =  Lu, Yb).

    PubMed

    Zhang, Xiaozhe; Yin, Yuewei; Yang, Sen; Yang, Zhimao; Xu, Xiaoshan

    2017-04-26

    We have carried out the growth of h-RFeO3 (0 0 1) (R  =  Lu, Yb) thin films on Fe3O4 (1 1 1)/Al2O3 (0 0 1) substrates, and studied the effect of the h-RFeO3 (0 0 1)/Fe3O4 (1 1 1) interfaces on the epitaxy and magnetism. The observed epitaxial relations between h-RFeO3 and Fe3O4 indicate an unusual matching of Fe sub-lattices rather than a matching of O sub-lattices. The out-of-plane direction was found to be the easy magnetic axis for h-YbFeO3 (0 0 1) but the hard axis for Fe3O4 (1 1 1) in the h-YbFeO3 (0 0 1)/Fe3O4 (1 1 1)/Al2O3 (0 0 1) films, suggesting a perpendicular magnetic alignment at the h-YbFeO3 (0 0 1)/Fe3O4 (1 1 1) interface. These results indicate that Fe3O4 (1 1 1)/Al2O3 (0 0 1) could be a promising substrate for epitaxial growth of h-RFeO3 films of well-defined interface and for exploiting their spintronic properties.

  8. Efficient enhanced 1.54 μm emission in Er/Yb: LiNbO3 crystal codoped with Mg2+ ions

    NASA Astrophysics Data System (ADS)

    Zhang, Peixiong; Yin, Jigang; Zhang, LianHan; Liu, Youchen; Hong, Jiaqi; Ning, Kaijie; Chen, Zhi; Wang, Xiangyong; Shi, Chunjun; Hang, Yin

    2014-10-01

    Single crystals of Er: LiNbO3 and Er/Yb: LiNbO3 co-doped with and without Mg2+ ion were successfully prepared. The quality of the as-grown crystals were characterized. Yb3+ was demonstrated to increase an absorption efficiency at the range of 900-1000 nm. The use of Mg2+ codoping for enhancement of the Er3+:4I13/2 → 4I15/2 1.54 μm emissions were investigated. It was found that Mg2+ ion greatly increased Er3+ 1.54 μm emission by increasing nonradiative relaxation rate of 4I11/2 → 4I13/2 transition of Er3+ ion in Mg/Er/Yb: LiNbO3 crystal. The Mg2+ codoping also resulted in lengthening the lifetime of the 4I13/2 multiplet by 9% for the Mg/Yb/Er: LiNbO3 crystal when compared with the Yb/Er: LiNbO3 crystal. The nonradiative relaxation rate of 4I11/2 → 4I13/2 transition of Er3+ ion increases from 935 s-1 in Er/Yb: LiNbO3 crystal to 1040 s-1 in Mg/Er/Yb: LiNbO3 crystal. It was also found that the intensity of maximum phonon energy of Er: LiNbO3 at 872 cm-1 significantly strengthen by introducing the Mg2+ ion, leading to a more favourable condition for the nonradiative relaxation of 4I11/2 → 4I13/2 transition in Er3+ ion. We propose that the Mg/Er/Yb: LiNbO3 crystal may be a promising material for 1.54 μm laser applications.

  9. High-beam-quality, efficient operation of passively Q-switched Yb:YAG/Cr:YAG laser pumped by photonic-crystal surface-emitting laser

    NASA Astrophysics Data System (ADS)

    Guo, Xiaoyang; Tokita, Shigeki; Fujioka, Kana; Nishida, Hiro; Hirose, Kazuyoshi; Sugiyama, Takahiro; Watanabe, Akiyoshi; Ishizaki, Kenji; Noda, Susumu; Miyanaga, Noriaki; Kawanaka, Junji

    2017-07-01

    A passively Q-switched Yb:YAG/Cr:YAG laser pumped by a photonic-crystal surface-emitting laser (PCSEL) was developed. Yb:YAG crystal was cryogenically cooled by liquid nitrogen at 77 K. Excellent Gaussian beam profile ( M 2 = 1.02) and high slope efficiency of 58% were demonstrated without using a coupling optics between a laser material and PCSEL.

  10. Spectroscopic investigation of Dy3+:Lu2Si2O7 single crystal: A potential 589 nm laser medium

    NASA Astrophysics Data System (ADS)

    Huang, Jianhui; Chen, Yujin; Huang, Jianhua; Gong, Xinghong; Lin, Yanfu; Luo, Zundu; Huang, Yidong

    2017-10-01

    A trivalent dysprosium-doped Lu2Si2O7 single crystal was grown by the Czochralski method. Segregation coefficient of Dy3+ ion in the crystal is about 0.56. Spectroscopic properties of the crystal were investigated at room temperature. In particular, the polarized absorption spectra were analyzed using the Judd-Ofelt theory and the intensity parameters were determined. Then the spontaneous transition probabilities, branching ratios, and radiative lifetime related to the 4F9/2 multiplet were calculated. Emission cross-section for the 4F9/2 → 6H13/2 transition at 589 nm is up to 1.27 × 10-21 cm2 for E//Y polarization. Thermal conductivity of the crystal was measured to be 9.46 Wm-1K-1 at room temperature. The experimental results show that the Dy3+:Lu2Si2O7 crystal is a promising gain medium for solid state 589 nm laser.

  11. High-power efficient cw and pulsed lasers based on bulk Yb : KYW crystals with end diode pumping

    SciTech Connect

    Kim, G H; Yang, G H; Lee, D S; Kulik, Alexander V; Sall', E G; Chizhov, S A; Yashin, V E; Kang, U

    2012-04-30

    End-diode-pumped lasers based on one and two Yb : KYW crystals operating in cw and Q-switched regimes, as well as in the regime of mode-locking, are studied. The single-crystal laser generated stable ultrashort (shorter than 100 fs) laser pulses at wavelengths of 1035 and 1043 nm with an average power exceeding 1 W. The average output power of the two-crystal laser exceeded 18 W in the cw regime and 16 W in the Q-switched regime with a slope efficiency exceeding 30%.

  12. Evaluation of spectroscopic properties of Er3+/Yb3+/Pr3+: SrGdGa3O7 crystal for use in mid-infrared lasers

    PubMed Central

    Xia, Houping; Feng, Jianghe; Wang, Yan; Li, Jianfu; Jia, Zhitai; Tu, Chaoyang

    2015-01-01

    Er3+/Yb3+/Pr3+: SrGdGa3O7 crystal was firstly grown by Czochralski method. Detailed spectroscopic analyses of Er3+/Yb3+/Pr3+: SrGdGa3O7 were carried out. Besides better absorption characteristic, the spectra of Er3+/Yb3+/Pr3+: SrGdGa3O7 show weaker up-conversion and near-infrared emissions as well as superior mid-infrared emission in comparison to Er3+: SrGdGa3O7 and Er3+/Yb3+: SrGdGa3O7 crystals. Furthermore, the self-termination effect for Er3+ 2.7 μm laser is suppressed successfully because the fluorescence lifetime of the 4I13/2 lower level of Er3+ decreases markedly while that of the upper 4I11/2 level changes slightly in Er3+/Yb3+/Pr3+: SrGdGa3O7 crystal. The sensitization effect of Yb3+ and deactivation effect of Pr3+ ions as well as the energy transfer mechanism in Er3+/Yb3+/Pr3+: SrGdGa3O7 crystal were also studied in this work. The introduction of Yb3+ and Pr3+ is favorable for achieving an enhanced 2.7 μm emission in Er3+/Yb3+/Pr3+: SrGdGa3O7 crystal which can act as a promising candidate for mid-infrared lasers. PMID:26369289

  13. Evaluation of spectroscopic properties of Er(3+)/Yb(3+)/Pr(3+): SrGdGa3O7 crystal for use in mid-infrared lasers.

    PubMed

    Xia, Houping; Feng, Jianghe; Wang, Yan; Li, Jianfu; Jia, Zhitai; Tu, Chaoyang

    2015-09-15

    Er(3+)/Yb(3+)/Pr(3+): SrGdGa3O7 crystal was firstly grown by Czochralski method. Detailed spectroscopic analyses of Er(3+)/Yb(3+)/Pr(3+): SrGdGa3O7 were carried out. Besides better absorption characteristic, the spectra of Er(3+)/Yb(3+)/Pr(3+): SrGdGa3O7 show weaker up-conversion and near-infrared emissions as well as superior mid-infrared emission in comparison to Er(3+): SrGdGa3O7 and Er(3+)/Yb(3+): SrGdGa3O7 crystals. Furthermore, the self-termination effect for Er(3+) 2.7 μm laser is suppressed successfully because the fluorescence lifetime of the (4)I(13/2) lower level of Er(3+) decreases markedly while that of the upper (4)I(11/2) level changes slightly in Er(3+)/Yb(3+)/Pr(3+): SrGdGa3O7 crystal. The sensitization effect of Yb(3+) and deactivation effect of Pr(3+) ions as well as the energy transfer mechanism in Er(3+)/Yb(3+)/Pr(3+): SrGdGa3O7 crystal were also studied in this work. The introduction of Yb(3+) and Pr(3+) is favorable for achieving an enhanced 2.7 μm emission in Er(3+)/Yb(3+)/Pr(3+): SrGdGa3O7 crystal which can act as a promising candidate for mid-infrared lasers.

  14. Resolution of the discrepancy between the variation of the physical properties of Ce1-xYbxCoIn5 single crystals and thin films with Yb composition

    SciTech Connect

    Jang, S.; White, B. D.; Lum, I. K.; Kim, H.; Tanatar, M. A.; Straszheim, W. E.; Prozorov, R.; Keiber, T.; Bridges, F.; Shu, L.; Baumbach, R. E.; Janoschek, M.; Maple, M. B.

    2014-11-18

    The extraordinary electronic phenomena including an Yb valence transition, a change in Fermi surface topology, and suppression of the heavy fermion quantum critical field at a nominal concentration x≈0.2 have been found in the Ce1-xYbxCoIn5 system. These phenomena have no discernable effect on the unconventional superconductivity and normal-state non-Fermi liquid behaviour that occur over a broad range of x up to ~0.8. However, the variation of the coherence temperature T* and the superconducting critical temperature Tc with nominal Yb concentration x for bulk single crystals is much weaker than that of thin films. To determine whether differences in the actual Yb concentration of bulk single crystals and thin film samples might be responsible for these discrepancies, we employed Vegard’s law and the spectroscopically determined values of the valences of Ce and Yb as a function of x to determine the actual composition xact of bulk single crystals. This analysis is supported by energy-dispersive X-ray spectroscopy, wavelength-dispersive X-ray spectroscopy, and transmission X-ray absorption edge spectroscopy measurements. The actual composition xact is found to be about one-third of the nominal concentration x up to x~0.5, and resolves the discrepancy between the variation of the physical properties of Ce1-xYbxCoIn5 single crystals and thin films with Yb concentration.

  15. An All-Solid Cryocooler to 100K Based on Optical Refrigeration in Yb:YLF Crystals

    DTIC Science & Technology

    2014-05-06

    Bahae University of New Mexico Department of Physics and Astronomy 1919 Lomas Blvd., NE Albuquerque, NM 87131 6 May 2014 Final Report...in Yb:YLF Crystals 5b. GRANT NUMBER 5c. PROGRAM ELEMENT NUMBER 62601F 6. AUTHOR(S) 5d. PROJECT NUMBER 8809 Mansoor Sheik- Bahae 5e. TASK NUMBER...intentionally left blank) Approved for public release; distribution is unlimited. i Approved for public release; distribution is unlimited. Table of

  16. Syntheses, structures, and magnetic properties of a family of heterometallic heptanuclear [Cu5Ln2] (Ln = Y(III), Lu(III), Dy(III), Ho(III), Er(III), and Yb(III)) complexes: observation of SMM behavior for the Dy(III) and Ho(III) analogues.

    PubMed

    Chandrasekhar, Vadapalli; Dey, Atanu; Das, Sourav; Rouzières, Mathieu; Clérac, Rodolphe

    2013-03-04

    Sequential reaction of the multisite coordination ligand (LH3) with Cu(OAc)2·H2O, followed by the addition of a rare-earth(III) nitrate salt in the presence of triethylamine, afforded a series of heterometallic heptanuclear complexes containing a [Cu5Ln2] core {Ln = Y(1), Lu(2), Dy(3), Ho(4), Er(5), and Yb(6)}. Single-crystal X-ray crystallography reveals that all the complexes are dicationic species that crystallize with two nitrate anions to compensate the charge. The heptanuclear aggregates in 1-6 are centrosymmetrical complexes, with a hexagonal-like arrangement of six peripheral metal ions (two rare-earth and four copper) around a central Cu(II) situated on a crystallographic inversion center. An all-oxygen environment is found to be present around the rare-earth metal ions, which adopt a distorted square-antiprismatic geometry. Three different Cu(II) sites are present in the heptanuclear complexes: two possess a distorted octahedral coordination sphere while the remaining one displays a distorted square-pyramidal geometry. Detailed static and dynamic magnetic properties of all the complexes have been studied and revealed the single-molecule magnet behavior of the Dy(III) and Ho(III) derivatives.

  17. Transparent oxyfluoride glass ceramics co-doped with Er 3+ and Yb 3+ - Crystallization and upconversion spectroscopy

    NASA Astrophysics Data System (ADS)

    Gugov, I.; Müller, M.; Rüssel, C.

    2011-05-01

    Transparent glass ceramics in the system SiO 2-B 2O 3-PbO-CdO-PbF 2-CdF 2-YbF 3-ErF 3 showing infrared to visible anti-Stokes (upconversion) luminescence are studied in the present work. The glass compositions have been optimized in order to reduce the melting temperature and, hence, to obtain laboratory scale samples with good optical quality. Erbium-doped nanoscale Pb 4Yb 3F 17 crystals are precipitated in the precursor glasses during annealing at temperatures 30-40 K above Tg. A kinetically self-constrained growth explains the nano sizes of the crystals. Both the Stokes and anti-Stokes luminescence spectra of glasses could be explained with clustering of the Yb 3+ and Er 3+ ions in fluorine-rich regions. At the annealing temperature these regions act as nucleation precursors. The crystal growth further enhances the local concentration of these ions. Consequently, a series of energy transfer and energy cross relaxation processes occurs between adjacent rare earth ions leading to the observed luminescence spectra of the glass ceramics studied.

  18. Study of 57Fe Mössbauer effect in RFe2Zn20 ( R = Lu, Yb, Gd)

    SciTech Connect

    Bud’ko, Sergey L.; Kong, Tai; Ma, Xiaoming; Canfield, Paul C.

    2015-08-04

    In this document we report measurements of 57Fe Mössbauer spectra for RFe2Zn20 (R = Lu, Yb, Gd) from ~ 4.5 K to room temperature. The obtained isomer shift values are very similar for all three compounds, their temperature dependence was analyzed within the Debye model and resulted in an estimate of the Debye temperatures of 450-500 K. The values of quadrupole splitting at room temperature change with the cubic lattice constant a in a linear fashion. For GdFe2Zn20, ferromagnetic order is seen as an appearance of a sextet in the spectra. The 57Fe site hyperfine field for T → 0 was evaluated to be ~ 2.4 T.

  19. Sub-10 nm Sr2LuF7:Yb/Er@Sr2GdF7@SrF2 Up-Conversion Nanocrystals for Up-Conversion Luminescence-Magnetic Resonance-Computed Tomography Trimodal Bioimaging.

    PubMed

    Chen, Cailing; Liu, Jianhua; Chen, Ying; Li, Chunguang; Liu, Xiaomin; Huang, He; Liang, Chen; Lou, Yue; Shi, Zhan; Feng, Shouhua

    2017-02-22

    Herein, sub-10 nm core-shell nanocrystals (NCs), which select Sr2LuF7:Yb/Er as core, Sr2GdF7 as middle shell, and SrF2 as an outermost shell, were synthesized by a seed-mediated growth process. The NCs possess good crystallinity, morphology, and up-conversion luminescent properties. After modification by polyethylenimine branched (PEI), in vitro cell up-conversion imaging with low autofluorescence was realized. Due to the presence of Gd(3+) ions, in vivo magnetic resonance (MR) imaging was also achieved with these designed NCs. More significantly, these special core-shell NCs exhibited high contrast in in vivo X-ray computed tomography (CT) imaging because of their good X-ray absorption ability. These results indicate that the core-shell up-conversion NCs can serve as promising contrast agents for up-conversion luminescence-MR-CT trimodal bioimaging.

  20. Crystal growth of CW diode-pumped (Er3+,Yb3+):GdAl3(BO3)4 laser material

    NASA Astrophysics Data System (ADS)

    Maltsev, V. V.; Koporulina, E. V.; Leonyuk, N. I.; Gorbachenya, K. N.; Kisel, V. E.; Yasukevich, A. S.; Kuleshov, N. V.

    2014-09-01

    Phase relationships in the Er:YbxGd1-xAl3(BO3)4-K2Mo3O10-B2O3-(Gd,Er,Yb)2O3 (x=0-0.2, Er-1 at%) system were studied in the temperature range from 1150 to 900 °С. Multicomponent melts of 55 mol%K2Mo3O10-45 mol% B2O3 (I) and 55 mol% K2Mo3O10-40 mol% B2O3-5 mol% (Gd,Er,Yb)2O3 (II) were suggested as reasonable fluxes for high-temperature solution growth of (Yb3+,Er3+):GdAl3(BO3)4 single crystals. Yb0.15Gd0.85Al3(BO3)4 solubility in the complex flux of II composition has been found as varying from 17 to 9.5 mol% with decreasing temperature in the interval of 1000-800 °C. As a result, (Er,Yb):GdAB single crystals with high optical quality and sizes up to 20×10×10 mm were grown on dipped "point" seeds. Absorption and stimulated emission spectra, emission lifetimes, and efficiencies of energy transfer from Yb3+ to Er3+ ions were determined. Highly efficient continuous-wave diode-pumped laser operation of (Er,Yb):GdAl3(BO3)4 crystal was realized.

  1. Orthorombic Yb:Li2Zn2(MoO4)3—a novel potential crystal for broadly tunable lasers

    NASA Astrophysics Data System (ADS)

    Kurilchik, Sergei; Loiko, Pavel; Yasukevich, Anatol; Trifonov, Vyacheslav; Volokitina, Anna; Vilejshikova, Elena; Kisel, Viktor; Mateos, Xavier; Baranov, Alexander; Goriev, Oleg; Kuleshov, Nikolay; Pavlyuk, Anatoly

    2017-08-01

    Crystal with composition Li2Zn2(MoO4)3 doped with 0.7 at.% Yb (Yb:LiZnMo), with high optical quality and a length of a few cm is grown from the flux using Li2MoO4 as a solvent. Yb:LiZnMo is orthorombic (sp. gr. Pnma, a  =  5.0843 Å, b  =  10.4927 Å, c  =  17.6742 Å, Z  =  4). Polarized Raman spectra are studied for this crystal; the most intense band is observed at 898 cm-1. The absorption, stimulated-emission and gain cross-sections of Yb3+ ions are determined for the principal light polarizations, E || a, b, c. The maximum σ SE  =  6.6  ×  10-21 cm2 at 1011 nm for E || b. The gain bandwidth for Yb:LiZnMo is up to ~50 nm. The radiative lifetime of the Yb3+ ions is 1.55 ms. The Yb:LiZnMo crystals are very promising for broadly tunable lasers.

  2. Growth and optical properties of Yb3+ and Tb3+ codoped BaB2O4 crystals

    NASA Astrophysics Data System (ADS)

    Solntsev, V. P.; Yelisseyev, A. P.; Bekker, T. B.; Kokh, A. E.; Stonoga, S. Yu.; Davydov, A. V.; Maillard, A.

    2012-11-01

    Optical absorption and luminescence spectra of ytterbium and terbium codoped BaB2O4 (β-BBO and α-BBO) crystals grown in different conditions have been studied. Low-temperature absorption peaks were observed in all samples. Features related to rare earth ions were observed in absorption and luminescence spectra. Absorption and emission in the range 860-1000 nm are caused by 2F5/2↔2F7/2 transitions in Yb3+ ions. Emission peaks at 500, 550, 590 and 630 nm correspond to 5D4→7F6, 7F5, 7F4, and 7F3 transitions of Tb3+ ions, respectively. The probable reasons of variations in spectroscopic features related to Yb in BBO host are discussed. It has been shown that the replacement of Ва2+ by Yb3+ in the lattice of ВаВ2О4 results in the decrease in the symmetry of oxygen surrounding of Yb3+.

  3. Synthesis, crystal structure, and magnetism of A2Co12As7 (A=Ca, Y, Ce–Yb)

    DOE PAGES

    Tan, Xiaoyan; Ovidiu Garlea, V.; Chai, Ping; ...

    2015-08-28

    In this study, ternary intermetallics, A2Co12As7 (A=Ca, Y, Ce–Yb), have been synthesized by annealing mixtures of elements in molten Bi at 1223 K. The materials obtained crystallize in the P63/m variant of the Zr2Fe12P7 structure type. The unit cell volume shows a monotonic decrease with the increasing atomic number of the rare-earth metal, with the exception of Ce-, Eu-, and Yb-containing compounds. An examination of these outliers with X-ray absorption near edge structures (XANES) spectroscopy revealed mixed valence of Ce, Eu, and Yb, with the average oxidation states of +3.20(1), +2.47(5), and +2.91(1), respectively, at room temperature. Magnetic behavior ofmore » A2Co12As7 is generally characterized by ferromagnetic ordering of Co 3d moments at 100–140 K, followed by low-temperature ordering of rare-earth 4f moments. The 3d-4f magnetic coupling changes from antiferromagnetic for A=Pr–Sm to ferromagnetic for A=Ce and Eu–Yb. Finally, polarized neutron scattering experiments were performed to support the postulated ferro- and ferrimagnetic ground states for Ce2Co12As7 and Nd2Co12As7, respectively.« less

  4. Synthesis, crystal structure, and magnetism of A2Co12As7 (A=Ca, Y, Ce-Yb)

    NASA Astrophysics Data System (ADS)

    Tan, Xiaoyan; Ovidiu Garlea, V.; Chai, Ping; Geondzhian, Andrey Y.; Yaroslavtsev, Alexander A.; Xin, Yan; Menushenkov, Alexey P.; Chernikov, Roman V.; Shatruk, Michael

    2016-04-01

    Ternary intermetallics, A2Co12As7 (A=Ca, Y, Ce-Yb), have been synthesized by annealing mixtures of elements in molten Bi at 1223 K. The materials obtained crystallize in the P63/m variant of the Zr2Fe12P7 structure type. The unit cell volume shows a monotonic decrease with the increasing atomic number of the rare-earth metal, with the exception of Ce-, Eu-, and Yb-containing compounds. An examination of these outliers with X-ray absorption near edge structures (XANES) spectroscopy revealed mixed valence of Ce, Eu, and Yb, with the average oxidation states of +3.20(1), +2.47(5), and +2.91(1), respectively, at room temperature. Magnetic behavior of A2Co12As7 is generally characterized by ferromagnetic ordering of Co 3d moments at 100-140 K, followed by low-temperature ordering of rare-earth 4f moments. The 3d-4f magnetic coupling changes from antiferromagnetic for A=Pr-Sm to ferromagnetic for A=Ce and Eu-Yb. Polarized neutron scattering experiments were performed to support the postulated ferro- and ferrimagnetic ground states for Ce2Co12As7 and Nd2Co12As7, respectively.

  5. Intervalence charge transfer luminescence: interplay between anomalous and 5d - 4f emissions in Yb-doped fluorite-type crystals.

    PubMed

    Barandiarán, Zoila; Seijo, Luis

    2014-12-21

    In this paper, we report the existence of intervalence charge transfer (IVCT) luminescence in Yb-doped fluorite-type crystals associated with Yb(2+)-Yb(3+) mixed valence pairs. By means of embedded cluster, wave function theory ab initio calculations, we show that the widely studied, very broad band, anomalous emission of Yb(2+)-doped CaF2 and SrF2, usually associated with impurity-trapped excitons, is, rather, an IVCT luminescence associated with Yb(2+)-Yb(3+) mixed valence pairs. The IVCT luminescence is very efficiently excited by a two-photon upconversion mechanism where each photon provokes the same strong 4f(14)-1A1g→ 4f(13)((2)F7/2)5deg-1T1u absorption in the Yb(2+) part of the pair: the first one, from the pair ground state; the second one, from an excited state of the pair whose Yb(3+) moiety is in the higher 4f(13)((2)F5/2) multiplet. The Yb(2+)-Yb(3+) → Yb(3+)-Yb(2+) IVCT emission consists of an Yb(2+) 5deg → Yb(3+) 4f7/2 charge transfer accompanied by a 4f7/2 → 4f5/2 deexcitation within the Yb(2+) 4f(13) subshell: [(2)F5/25deg,(2)F7/2] → [(2)F7/2,4f(14)]. The IVCT vertical transition leaves the oxidized and reduced moieties of the pair after electron transfer very far from their equilibrium structures; this explains the unexpectedly large band width of the emission band and its low peak energy, because the large reorganization energies are subtracted from the normal emission. The IVCT energy diagrams resulting from the quantum mechanical calculations explain the different luminescent properties of Yb-doped CaF2, SrF2, BaF2, and SrCl2: the presence of IVCT luminescence in Yb-doped CaF2 and SrF2; its coexistence with regular 5d-4f emission in SrF2; its absence in BaF2 and SrCl2; the quenching of all emissions in BaF2; and the presence of additional 5d-4f emissions in SrCl2 which are absent in SrF2. They also allow to interpret and reproduce recent experiments on transient photoluminescence enhancement in Yb(2+)-doped CaF2 and SrF2, the

  6. Intervalence charge transfer luminescence: Interplay between anomalous and 5d - 4f emissions in Yb-doped fluorite-type crystals

    NASA Astrophysics Data System (ADS)

    Barandiarán, Zoila; Seijo, Luis

    2014-12-01

    In this paper, we report the existence of intervalence charge transfer (IVCT) luminescence in Yb-doped fluorite-type crystals associated with Yb2+-Yb3+ mixed valence pairs. By means of embedded cluster, wave function theory ab initio calculations, we show that the widely studied, very broad band, anomalous emission of Yb2+-doped CaF2 and SrF2, usually associated with impurity-trapped excitons, is, rather, an IVCT luminescence associated with Yb2+-Yb3+ mixed valence pairs. The IVCT luminescence is very efficiently excited by a two-photon upconversion mechanism where each photon provokes the same strong 4f14-1A1g→ 4f13(2F7/2)5deg-1T1u absorption in the Yb2+ part of the pair: the first one, from the pair ground state; the second one, from an excited state of the pair whose Yb3+ moiety is in the higher 4f13(2F5/2) multiplet. The Yb2+-Yb3+ → Yb3+-Yb2+ IVCT emission consists of an Yb2+ 5deg → Yb3+ 4f7/2 charge transfer accompanied by a 4f7/2 → 4f5/2 deexcitation within the Yb2+ 4f13 subshell: [2F5/25deg,2F7/2] → [2F7/2,4f14]. The IVCT vertical transition leaves the oxidized and reduced moieties of the pair after electron transfer very far from their equilibrium structures; this explains the unexpectedly large band width of the emission band and its low peak energy, because the large reorganization energies are subtracted from the normal emission. The IVCT energy diagrams resulting from the quantum mechanical calculations explain the different luminescent properties of Yb-doped CaF2, SrF2, BaF2, and SrCl2: the presence of IVCT luminescence in Yb-doped CaF2 and SrF2; its coexistence with regular 5d-4f emission in SrF2; its absence in BaF2 and SrCl2; the quenching of all emissions in BaF2; and the presence of additional 5d-4f emissions in SrCl2 which are absent in SrF2. They also allow to interpret and reproduce recent experiments on transient photoluminescence enhancement in Yb2+-doped CaF2 and SrF2, the appearance of Yb2+ 4f-5d absorption bands in the excitation

  7. Upconversion white-light emission in Ho3+/Yb3+/Tm3+ tridoped LiNbO3 single crystal.

    PubMed

    Xing, Lili; Wu, Xiaohong; Wang, Rui; Xu, Wei; Qian, Yannan

    2012-09-01

    Ho3+/Yb3+/Tm3+ tridoped LiNbO3 single crystal exhibiting intense upconversion white light under 980 nm excitation has been successfully fabricated by the Czochralski method. The tridoped LiNbO3 single crystal offers power dependent color tuning properties by simply changing excitation power. Efficient three-photon blue upconversion emission and two-photon green and red upconversion emissions have been observed. In addition, the red emission of Ho3+ originates dominantly from the nonradiative decay of green emission. The LiNbO3 with upconversion white light will be a potential laser candidate material.

  8. Laser oscillation of Yb:KLu(WO4)2 crystal polarized along the N(g) principal optical axis.

    PubMed

    Liu, Junhai; Zhang, Huaijin; Han, Wenjuan; Petrov, Valentin; Wang, Jiyang

    2008-03-31

    Efficient polarized laser oscillation along the N(g) principal optical axis is demonstrated at room temperature with a N(p)-cut Yb:KLu(WO4)2 crystal in a three-mirror folded resonator pumped by a Ti:sapphire laser at 981 nm. To our knowledge, this is the first laser study of this polarization for bulk crystals of this type. A continuous-wave output power of 0.55 W was obtained at 1044 nm for an absorbed pump power of 1.44 W, leading to optical-to-optical and slope efficiencies of 38% and 52%, respectively.

  9. High power cw and mode-locked oscillators based on Yb:KYW multi-crystal resonators.

    PubMed

    Calendron, A-L; Wentsch, K S; Lederer, M J

    2008-11-10

    We report on a high power diode-pumped laser using multiple bulk Yb:KY(WO(4))(2) (KYW) crystals in a resonator optimised for this operation. From a dual-crystal resonator we obtain more than 24 W of cw-power in a TEM(00) mode limited by the available pump power. We also present results for semiconductor saturable absorber mirror (SESAM) mode-locking in the soliton as well as positive dispersion regime with average output powers of 14.6 W and 17 W respectively.

  10. High peak power miniature Yb:CNGG disordered crystal laser end-pumped by a 935-nm diode

    NASA Astrophysics Data System (ADS)

    Dai, Qibiao; Yi, Hongying; Chen, Xiaowen; Han, Wenjuan; Zhang, Huaijin; Wang, Shiwu; Liu, Junhai

    2014-04-01

    We report on an efficient miniature Yb:CNGG disordered crystal laser, which is passively Q-switched with a Cr4+:YAG crystal plate acting as saturable absorber. An average output power of 1.35 W is generated at a pulse repetition rate of 5.55 kHz with a slope efficiency of 42%; the resulting laser pulse energy and duration are respectively 243 μJ and 3.0 ns, while the peak power is as high as 81 kW.

  11. Development of a large-area monolithic 4×4 MPPC array for a future PET scanner employing pixelized Ce:LYSO and Pr:LuAG crystals

    NASA Astrophysics Data System (ADS)

    Kato, T.; Kataoka, J.; Nakamori, T.; Miura, T.; Matsuda, H.; Sato, K.; Ishikawa, Y.; Yamamura, K.; Kawabata, N.; Ikeda, H.; Sato, G.; Kamada, K.

    2011-05-01

    We have developed a new type of large-area monolithic Multi-Pixel Photon Counter (MPPC) array consisting of a 4×4 matrix of 3×3 mm 2 pixels. Each pixel comprises 3600 Geiger mode avalanche photodiodes (APDs) that achieve an average gain of 9.68×10 5 at 71.9 V at 0 °C with variations of only ±7.2% over 4×4 pixels. Excellent uniformity was also obtained for photon detection efficiencies (PDE) of ±6.4%, whilst dark count rates at the single photoelectron (1 p.e.) level amounted to ≃2 Mcps/pixel, measured at 0 °C. As the first step toward using the device in scintillation photon detectors, we fabricated a prototype gamma-ray camera consisting of an MPPC array optically coupled with a scintillator matrix, namely a 4×4 array of 3×3 ×10 mm 3 crystals. Specifically, we tested the performance with Ce-doped (Lu, Y) 2(SiO 4)O (Ce:LYSO), Pr-doped Lu 3Al 5O 12 (Pr:LuAG) and "surface coated" Pr:LuAG (Pr:LuAG (WLS)) matrices whereby the emission peak of Pr:LuAG was shifted from 310 to 420 nm via a wavelength shifter (WLS). Average energy resolutions of 13.83%, 14.70% and 13.96% (FWHM) were obtained for 662 keV gamma-rays, as measured at 0 °C with Ce:LYSO, Pr:LuAG and Pr:LuAG (WLS) scintillator matrices, respectively. We confirmed that the effective PDE for Pr:LuAG (WLS) had improved by more than 30% compared to original, non-coated Pr:LuAG matrix. These results suggest that a large-area monolithic MPPC array developed here could be promising for future medical imaging, particularly in positron emission tomography (PET).

  12. 2.0-μm emission and energy transfer of Ho3+/Yb3+ co-doped LiYF4 single crystal excited by 980 nm

    NASA Astrophysics Data System (ADS)

    Yang, Shuo; Xia, Hai-Ping; Jiang, Yong-Zhang; Zhang, Jia-Zhong; Jiang, Dong-Sheng; Wang, Cheng; Feng, Zhi-Gang; Zhang, Jian; Gu, Xue-Mei; Zhang, Jian-Li; Jiang, Hao-Chuan; Chen, Bao-Jiu

    2015-06-01

    Ho3+/Yb3+ co-doped LiYF4 single crystals with various Yb3+ concentrations and ˜ 0.98 mol% Ho3+ concentration are grown by the Bridgman method under the conditions of taking LiF and YF3 as raw materials and a temperature gradient (40 °C/cm-50 °C/cm) for the solid-liquid interface. The luminescent performances of the crystals are investigated through emission spectra, infrared transmittance spectrum, emission cross section, and decay curves under excitation by 980 nm. Compared with the Ho3+ single-doped LiYF4 crystal, the Ho3+/Yb3+ co-doped LiYF4 single crystal has an obviously enhanced emission band from 1850 nm to 2150 nm observed when excited by a 980-nm diode laser. The energy transfer from Yb3+ to Ho3+ and the optimum fluorescence emission around 2.0 μm of Ho3+ ions are investigated. The maximum emission cross section of the above sample at 2.0 μm is calculated to be 1.08×10-20 cm2 for the LiYF4 single crystal of 1-mol% Ho3+ and 6-mol% Yb3+ according to the measured absorption spectrum. The high energy transfer efficiency of 88.9% from Yb3+ to Ho3+ ion in the sample co-doped by Ho3+ (1 mol%) and Yb3+ (8 mol%) demonstrates that the Yb3+ ions can efficiently sensitize the Ho3+ ions. Project supported by the National Natural Science Foundation of China (Grant Nos. 51472125 and 51272109) and the K.C. Wong Magna Fund in Ningbo University, China (Grant No. NBUWC001).

  13. Large electric polarization in high pressure synthesized orthorhombic manganites RMnO3 (R=Ho,Tm,Yb and Lu) by using the double-wave PE loop measurements

    NASA Astrophysics Data System (ADS)

    Chai, Y. S.; Oh, Y. S.; Manivannan, N.; Yang, Y. S.; Kim, Kee Hoon; Feng, S. M.; Wang, L. J.; Jin, C. Q.

    2009-03-01

    The magnitude of electric polarization via the conventional pyroelectric current and/or PE loop measurements often is ambiguous due to resistive components of the sample. To avoid this, a new technique called the double-wave method has been recently developed [1], in which only hysteretic PE components can be measured. Using this technique, we have measured the ferroelectric polarization of the orthorhombic RMnO3 (R=Ho, Tm, Yb, and Lu) synthesized under high pressure. Large remnant polarization Pr up to 920 μC/m^2 is observed at 10 K for LuMnO3. Furthermore, the Pr vs. temperature data from the PE loop has shown consistency with that measured through the pyroelectric current measurements, supporting a theoretical prediction of large polarization in the E-type spin structure in this system [2]. We also discuss the influence of thermal histories on the ferroelectric domain dynamics and possible internal bias field effects originating from oxygen vacancies in RMnO3. [1] M. Fukunaga, et al. J. Phys. Soc. Jpn. 77, 064706 (2008). [2] I. A. Sergienko, et al. Phys. Rev. Lett., 97, 227204 (2006)

  14. Optical characterization of Tm3+ in LiYF4 and LiLuF4 crystals

    NASA Astrophysics Data System (ADS)

    Xiong, Jing; Peng, HaiYan; Hu, Pengchao; Hang, Yin; Zhang, Lianhan

    2010-05-01

    A comparative study of the optical properties of Tm3+ in LiYF4 (YLF) and LiLuF4 (LLF) crystals is presented. Room temperature polarized absorption spectra and fluorescence spectra for Tm3+ in LYF and LLF were measured and analysed. By applying the Judd-Ofelt approach, the intensity parameters Ω2,4,6 were calculated. The radiative transition rates, branching ratios and radiative lifetimes were also obtained. The results were analysed and compared between these two samples, indicating that both of them are favourable laser media.

  15. Electron paramagnetic resonance of Cr{sup 3+} ions in ABO{sub 3} (A = Sc, Lu, In) diamagnetic crystals

    SciTech Connect

    Vorotynov, A. M. Ovchinnikov, S. G.; Rudenko, V. V.; Vorotynova, O. V.

    2016-04-15

    A magnetic resonance method is applied to the investigation of a number of isostructural diamagnetic compounds ABO{sub 3} (A = Sc, Lu, In) with small additions of Cr{sup 3+} ions (S = 3/2) sufficient to observe single-ion spectra. It is shown that the resonance spectra for isolated Cr{sup 3+} ions can be described to a good accuracy by the ordinary axial spin Hamiltonian for 3d ions in octahedral oxygen environment. The parameters of the spin Hamiltonian are determined. It is established that Cr{sup 3+} ions in these crystals are characterized by easy-axis-type anisotropy.

  16. Crystal fields, disorder, and antiferromagnetic short-range order in Yb0.24Sn0.76Ru

    NASA Astrophysics Data System (ADS)

    Klimczuk, T.; Wang, C. H.; Lawrence, J. M.; Xu, Q.; Durakiewicz, T.; Ronning, F.; Llobet, A.; Trouw, F.; Kurita, N.; Tokiwa, Y.; Lee, Han-Oh; Booth, C. H.; Gardner, J. S.; Bauer, E. D.; Joyce, J. J.; Zandbergen, H. W.; Movshovich, R.; Cava, R. J.; Thompson, J. D.

    2011-08-01

    We report extensive measurements on a new compound (Yb0.24Sn0.76)Ru that crystallizes in the cubic CsCl structure. Valence-band photoemission (PES) and L3 x-ray absorption show no divalent component in the 4f configuration of Yb. Inelastic neutron scattering (INS) indicates that the eight-fold degenerate J-multiplet of Yb3+ is split by the crystalline electric field (CEF) into a Γ7-doublet ground state and a Γ8 quartet at an excitation energy 20 meV. The magnetic susceptibility can be fit very well by this CEF scheme under the assumption that a Γ6-excited state resides at 32 meV; however, the Γ8/Γ6 transition expected at 12 meV was not observed in the INS. The resistivity follows a Bloch-Grüneisen law shunted by a parallel resistor, as is typical of systems subject to phonon scattering with no apparent magnetic scattering. All of these properties can be understood as representing simple local moment behavior of the trivalent Yb ion. At 1 K there is a peak in specific heat that is too broad to represent a magnetic-phase transition, consistent with absence of magnetic reflections in neutron diffraction. On the other hand this peak also is too narrow to represent the Kondo effect in the Γ7-doublet ground state. On the basis of the field dependence of the specific heat, we argue that antiferromagnetic (AF) short-range order (SRO) (possibly coexisting with Kondo physics) occurs at low temperatures. The long-range magnetic order is suppressed because the Yb site occupancy is below the percolation threshold for this disordered compound.

  17. Dextran-coated fluorapatite crystals doped with Yb3+/Ho3+ for labeling and tracking chondrogenic differentiation of bone marrow mesenchymal stem cells in vitro and in vivo.

    PubMed

    Hu, Xiaoqing; Zhu, Jingxian; Li, Xiyu; Zhang, Xin; Meng, Qingyang; Yuan, Lan; Zhang, Jiying; Fu, Xin; Duan, Xiaoning; Chen, Haifeng; Ao, Yingfang

    2015-06-01

    Upconversion fluorescent nanoparticles are becoming more widely used as imaging contrast agents, owing to their high resolution and penetration depth, and avoidance of tissue auto-fluorescence and photodamage to cells. Here, we synthesized upconversion fluorescent crystals from rare-earth Yb3+ and Ho3+ co-doped fluorapatite (FA:Yb3+/Ho3+) suitable for long-term tracking and monitoring cartilage development (chondrogenesis) in bone marrow mesenchymal stem cells (BMSCs) in vitro and in vivo. We initially determined the structure, morphology and luminescence of the products using X-ray powder diffraction, transmission electron microscopy and two-photon confocal microscopy. When excited at 980 nm, FA:Yb3+/Ho3+ crystals exhibited distinct upconversion fluorescence peaks at 543 nm and 654 nm. We then conjugated FA:Yb3+/Ho3+ crystals with dextran to enhance hydrophilicity, biocompatibility and cell penetration. Next, we employed the dextran-coated FA:Yb3+/Ho3+ crystals in labeling and tracking chondrogenic differentiation processes in BMSCs stably expressing green fluorescent protein (BMSCsGFP) in vitro and in vivo. Labeled BMSCsGFP were shown to reproducibly exhibit chondrogenic differentiation potential in RT-PCR analysis, histological assessment and immunohistochemistry. We observed continuous luminescence from the FA:Yb3+/Ho3+ upconversion crystals at 4 weeks and 12 weeks post transplantation in BMSCsGFP, while GFP fluorescence in both control and crystal-treated groups significantly decreased at 12 weeks after BMSCsGFP transplantation. We therefore demonstrate the high biocompatibility and stability of FA:Yb3+/Ho3+ crystals in tracking and monitoring BMSCs chondrogenesis in vitro and in vivo, highlighting their excellent cell labeling potential in cartilage tissue engineering. Copyright © 2015 Elsevier Ltd. All rights reserved.

  18. Low-temperature superstructures of a series of Cd6M (M = Ca, Y, Sr, Pr, Nd, Sm, Gd, Tb, Dy, Ho, Er, Tm, Yb and Lu) crystalline approximants

    NASA Astrophysics Data System (ADS)

    Nishimoto, Kazue; Sato, Takeru; Tamura, Ryuji

    2013-06-01

    The low-temperature (LT) superstructure and the phase transition temperature have been investigated for a series of Cd6M crystalline approximants by transmission electron microscopy as well as electrical resistivity measurements. Except for M = Lu, Cd6M is found to undergo a phase transition to a monoclinic phase at a low temperature and the transition temperature (Tc) scales well with the size of the M atom. For M = Ca, Y, Pr, Nd, Sm, Gd, Tb, Dy, Ho, Er and Tm the LT superstructure is explained by a \\sqrt{2}a\\times a\\times \\sqrt{2}a lattice with the space group C2/c, and for M = Sr and Yb a \\sqrt{2}a\\times 2 a\\times \\sqrt{2}a monoclinic lattice with P2/m. On the other hand, no phase transition is observed for M = Lu, indicating that a Cd4 tetrahedron at the cluster center remains disordered down to the lowest temperature, i.e. 16 K. It is shown that the volume inside the Cd20 dodecahedron plays a crucial role in the occurrence of the phase transition, and long-term aging in particular promotes the phase transition for late rare-earth elements such as Ho, Er and Tm, suggesting that the transition is sensitive to and is even hindered by disorder such as atomic vacancies. The absence of the transition for M = Lu is attributed to the highest activation energy for the transition due to the smallest volume inside the Cd20 dodecahedron.

  19. FUNDAMENTAL AREAS OF PHENOMENOLOGY (INCLUDING APPLICATIONS): Intrinsic Bistability and Critical Slowing in Tm3+/Yb3+ Codoped Laser Crystal with the Photon Avalanche Mechanism

    NASA Astrophysics Data System (ADS)

    Li, Li; Zhang, Xin-Lu; Chen, Li-Xue

    2009-06-01

    We present theoretically a novel intrinsic optical bistability (IOB) in the Tm3+/Yb3+ codoped system with a photon avalanche mechanism. Numerical simulations based on the rate equation model demonstrate distinct IOB hysteresis and critical slowing dynamics around the avalanche thresholds. Such an IOB characteristic in Tm3+/Yb3+ codoped crystal has potential applications in solid-state bistable optical displays and luminescence switchers in visible-infrared spectra.

  20. Gd(3+)-Yb(3+) Exchange Interactions in LiYb(x)Y(1-x)F4 Single Crystals

    DTIC Science & Technology

    2001-01-01

    fluorolanthanate phases," Inorg. Chem. 9, pp. 1096-1101, 1970. 6. L. E. Misiak, P. Mikolajczak and M. Subotowicz, "Lithium rare-earth fluoride crystal growth and...of Gd 34 in LiYF 4 determined by EPR," Solid State Commun. 45, pp. 1093-1098, 1983. 8. S. K. Misra, M. Kahrizi, P. Mikolajczak and L. E. Misiak, "EPR...and P. Mikolajczak , "EPR of Gd34 -doped single crystals of LiYbxY_,-F 4," Phys. Rev. B 38, pp. 8673-8682, 1988. 10. M. R. St. John and R. J. Myers

  1. The effect of Zn2+ ion on the UV-VIS-NIR and upconversion emission spectroscopy of Er3+ in Yb:Er:LiNbO3 crystal

    NASA Astrophysics Data System (ADS)

    Dai, Li; Jiao, Shanshan; Xu, Chao; Qian, Zhao; Li, Dayong; Lin, Jiaqi; Xu, Yuheng

    2014-03-01

    A series of Yb:Er:LiNbO3 crystals tridoped with x mol% Zn2+ ions (x = 1, 3, 5 and 8 mol%) was grown by Czochralski technique. The inductively coupled plasma atomic emission spectrometry (ICP-AES) was used to measure the concentration of Er3+ in the crystal. The UV-VIS-NIR absorption spectra of Zn:Yb:Er:LiNbO3 crystals were measured, and Judd-Ofelt (J-O) theory was applied to predict the J-O intensity parameters (Ωt) and spectroscopic quality factor (X). With 980 nm excitation, duration lengthening of 1.54 μm emission and intensity enhancement of green upconversion emission were observed for Zn:Yb:Er:LiNbO3 crystal.

  2. Energy transfer and visible-infrared quantum cutting photoluminescence modification in Tm-Yb codoped YPO(4) inverse opal photonic crystals.

    PubMed

    Wang, Siqin; Qiu, Jianbei; Wang, Qi; Zhou, Dacheng; Yang, Zhengwen

    2015-08-01

    YPO4:  Tm, Yb inverse opal photonic crystals were successfully synthesized by the colloidal crystal templates method, and the visible-infrared quantum cutting (QC) photoluminescence properties of YPO4:  Tm, Yb inverse opal photonic crystals were investigated. We obtained tetragonal phase YPO4 in all the samples when the samples sintered at 950°C for 5 h. The visible emission intensity of Tm3+ decreased significantly when the photonic bandgap was located at 650 nm under 480 nm excitation. On the contrary, the QC emission intensity of Yb3+ was enhanced as compared with the no photonic bandgap sample. When the photonic bandgap was located at 480 nm, the Yb3+ and Tm3+ light-emitting intensity weakened at the same time. We demonstrated that the energy transfer between Tm3+ and Yb3+ is enhanced by the suppression of the red emission of Tm3+. Additionally, the mechanisms for the influence of the photonic bandgap on the energy transfer process of the Tm3+, Yb3+ codoped YPO4 inverse opal are discussed.

  3. Influence of some impurities on the emission properties of CaF2:YbF3 crystals

    NASA Astrophysics Data System (ADS)

    Stef, Marius; Nicoara, Irina; Cirlan, Florina; Para, Irina; Velazquez, Matias; Buse, Gabriel

    2015-12-01

    Various concentrations of YbF3 -doped and NaF or PbF2 co-doped CaF2 crystals were grown using the conventional Bridgman method. Transparent colorless crystals were obtained in graphite crucible in vacuum using a shaped graphite furnace. The crystals have been cooled to room temperature using an established procedure. Room temperature absorption spectra have been obtained using a Shimadzu 1650PC spectrophotometer. Photoluminescent properties in IR spectral range were analyzed using a spectrofluorimeter Horiba Fluorolog 3. An IR laser diode at 932 nm was also used an directly injected in the equipment. The emission spectra are influenced by the concentration of co-dopant added to the melt, and the excitation wavelength. The high emission peak at 979 nm overlaps with the absorption peak. The highest intensity in the IR emission (around 1029 nm) is obtained for CaF2:0.72 mol% YbF3 crystal by excitation at 932 nm (diode lamp).

  4. Effects of scandium substitution on the crystal structure and luminescence properties of LuBO{sub 3}: Ce{sup 3+}

    SciTech Connect

    Wu, Yuntao; Ren, Guohao; Ding, Dongzhou; Pan, Shangke; Yang, Fan

    2012-10-15

    The calcite phase of LuBO{sub 3} and ScBO{sub 3} polycrystalline powders were synthesized by solid state reaction method, and the Lu{sub 1-x}Sc{sub x}BO{sub 3}:Ce (x=0.2, 0.5, 0.7) single crystals were grown by the Czochralski method. A large composition deviation between the initial polycrystalline powders and final single crystal was confirmed by electron probe micro-analysis. Raman spectroscopy revealed that moderate lattice disorder was induced by scandium substitution. However, based on the single crystal X-ray study, we finally concluded that the crystal structure of lutetium scandium orthoborate still crystallized in the rhombohedral system belonging to R3{sup -}c. Furthermore, the relationship between the energies of the five 5d levels of Ce{sup 3+} and the crystalline environment was revealed. The total redshift, total crystal field splitting, and centroid shift of Lu{sub 1-x}Sc{sub x}BO{sub 3}:Ce{sup 3+} were calculated based on their VUV excitation spectra. The variations trend of these observed spectroscopic parameters was in accordance with the predicted ones. - Graphical abstract: The crystal structure of Lu{sub 1-x}Sc{sub x}BO{sub 3}:Ce is rhombohedral system with R3{sup -}c space group. The relationship between the energies of the five Ce{sup 3+} 5d levels and the crystalline environment is established. Highlights: Black-Right-Pointing-Pointer Moderate lattice disorder is induced by scandium doping. Black-Right-Pointing-Pointer The crystal structure of Lu{sub 1-x}Sc{sub x}BO{sub 3}:Ce is rhombohedral system with R3{sup -}c space group. Black-Right-Pointing-Pointer Relationship between energies of Ce{sup 3+} 5d levels and crystalline environment is established. Black-Right-Pointing-Pointer The spectroscopic parameters are experimentally and theoretically calculated.

  5. Influence of rare earth cation size on the crystal structure in rare earth silicates, Na2RESiO4(OH) (RE = Sc, Yb) and NaRESiO4 (RE = La, Yb)

    NASA Astrophysics Data System (ADS)

    Latshaw, Allison M.; Wilkins, Branford O.; Chance, W. Michael; Smith, Mark D.; zur Loye, Hans-Conrad

    2016-01-01

    Crystals of Na2ScSiO4(OH) and Na2YbSiO4(OH) were synthesized at low temperatures using a sodium hydroxide based hydroflux, while crystals of NaLaSiO4 and NaYbSiO4 were grown at high temperatures using a sodium fluoride/sodium chloride eutectic flux. Both structure types were crystallized under reaction conditions that, when used for medium sized rare earths (RE = Pr, Nd, Sm - Tm) yield the Na5RE4X[SiO4]4 structure type, where X is OH in the hydroflux conditions and F in the eutectic flux conditions. Herein, we report the synthesis, structure, size effect, and magnetic properties of these compositions and introduce the new structure type of Na2RESiO4(OH), which crystallizes in the orthorhombic space group Pca21, of NaLaSiO4, which crystallizes in the orthorhombic space group Pna21, and of NaYbSiO4, which crystallizes in the orthorhombic space group Pnma, where both NaRESiO4 compounds have one silicon structural analog.

  6. An EPR study of rare-earth impurities in single crystals of the zircon-structure orthophosphates ScPO4, YPO4, and LuPO4 a)

    NASA Astrophysics Data System (ADS)

    Abraham, M. M.; Boatner, L. A.; Ramey, J. O.; Rappaz, M.

    1983-01-01

    Ceramic materials based on the lanthanide orthophosphate series of compounds are known to be highly stable both chemically and physically. These characteristics have recently led to an extensive evaluation of these substances as potential primary containment media for the disposal of high-level radioactive wastes. Since one important class of high-level nuclear waste (i.e., reprocessed light water reactor spent fuel) contains a relatively high concentration of various lanthanides, the solid state chemical properties of the mixed rare-earth and actinide-doped orthophosphates are of considerable practical interest. The Kramers' ions Ce3+, Nd3+, Dy3+, Er3+, Yb3+, and U3+ have been incorporated in single crystals of the tetragonal symmetry hosts ScPO4, YPO4, and LuPO4, and EPR spectroscopy has been used to verify the substitutional behavior of these ions and to investigate their electronic ground state properties. Principal axial spectroscopic splitting factors and hyperfine parameters were determined. These results are compared to those obtained for the same paramagnetic ions in other hosts characterized by crystal fields with tetragonal symmetry at the impurity-ion site.

  7. Anisotropic enhancement of Yb(3+) luminescence by disordered plasmonic networks self-assembled on RbTiOPO4 ferroelectric crystals.

    PubMed

    Sánchez-García, L; Ramírez, M O; Tserkezis, C; Sole, R; Carvajal, J J; Aguiló, M; Díaz, F; Bausá, L E

    2017-08-09

    Increasing Yb(3+) absorption efficiency is currently desired in a number of applications including bio-imaging, photovoltaics, near infrared driven photocatalysis or ultra-short pulsed solid-state lasers. In this work, silver nanoparticles, which are connected forming disordered networks, have been self-assembled on Yb(3+) doped RbTiOPO4 crystals to produce a remarkable enhancement of Yb(3+) absorption, and hence in the photoluminescence of this ion. The results are interpreted taking into account the near-field response of the plasmonic networks, which display strong amplification of the electric field at the maximum of Yb(3+) excitation at around 900 nm, together with the anisotropic character of the Yb(3+) transitions in RbTiOPO4. We show that in the near field regime, the scattering of the plasmonic networks produces additional polarization field components to those of the incident field, which allows access to the largest transition dipolar moment of Yb(3+) ions in RbTiOPO4. As a result, a much more efficient route for Yb(3+) excitation takes place at the immediacy of the plasmonic networks. This work provides fundamental insights for improving the optical properties of rare earth ions by the suitable design of metallic nanoparticle arrangements, and constitutes a promising step towards the development of new multifunctional solid-state lasers.

  8. Resolution of the discrepancy between the variation of the physical properties of Ce1-xYbxCoIn5 single crystals and thin films with Yb composition

    DOE PAGES

    Jang, S.; White, B. D.; Lum, I. K.; ...

    2014-11-18

    The extraordinary electronic phenomena including an Yb valence transition, a change in Fermi surface topology, and suppression of the heavy fermion quantum critical field at a nominal concentration x≈0.2 have been found in the Ce1-xYbxCoIn5 system. These phenomena have no discernable effect on the unconventional superconductivity and normal-state non-Fermi liquid behaviour that occur over a broad range of x up to ~0.8. However, the variation of the coherence temperature T* and the superconducting critical temperature Tc with nominal Yb concentration x for bulk single crystals is much weaker than that of thin films. To determine whether differences in the actualmore » Yb concentration of bulk single crystals and thin film samples might be responsible for these discrepancies, we employed Vegard’s law and the spectroscopically determined values of the valences of Ce and Yb as a function of x to determine the actual composition xact of bulk single crystals. This analysis is supported by energy-dispersive X-ray spectroscopy, wavelength-dispersive X-ray spectroscopy, and transmission X-ray absorption edge spectroscopy measurements. The actual composition xact is found to be about one-third of the nominal concentration x up to x~0.5, and resolves the discrepancy between the variation of the physical properties of Ce1-xYbxCoIn5 single crystals and thin films with Yb concentration.« less

  9. Thermal modeling of gain competition in Yb-doped large-mode-area photonic-crystal fiber amplifier.

    PubMed

    Rosa, Lorenzo; Coscelli, Enrico; Poli, Federica; Cucinotta, Annamaria; Selleri, Stefano

    2015-07-13

    We propose a new model for gain competition effects in high-power fiber amplifiers, which accounts for the thermal effects of heat load on the doped core overlap of the propagating light field. The full-vectorial nature of the fiber modes is modeled by an embedded finite-element method modal solver, and the temperature profile is calculated by a simple and efficient radial heat propagation solver. The model is applied to a Yb³⁺-doped LPF45 air-clad photonic-crystal fiber amplifier for coand counter-propagating pumping setups, showing gain competition in conditions of severe heat load.

  10. Anisotropy in the magnetic and multiferroic properties of LuFe2O4-δ single crystals with varying oxygen stoichiometry

    NASA Astrophysics Data System (ADS)

    Balakrishnan, G.; McKinnon, R. A.; Lees, M. R.

    2012-02-01

    LuFe2O4 is a multiferroic, where the origin of the ferroelectricity is attributed to electron correlations and directly linked to the charge ordering of Fe^2+ and Fe^3+ in the lattice. The multiferroic properties of this system are known to be sensitive to the oxygen stoichiometry. Large single crystals of LuFe2O4-δ with varying oxygen stoichiometry have been produced by the floating zone technique. Detailed magnetic susceptibility, dielectric constant and polarization measurements have been carried out along specific crystallographic axes of the single crystals over a wide temperature range to study the anisotropic properties. The effect of altering the Fe^2+/ Fe^3+ stochiometry on the physical properties of LuFe2O4-d is discussed.

  11. Lasing in a Tm : Yb{sub 3}Al{sub 5}O{sub 12} crystal pumped at 1.678 μm

    SciTech Connect

    Zavartsev, Yu D; Zagumennyi, A I; Kalachev, Yu L; Kutovoi, S A; Mikhailov, V A; Shcherbakov, I A

    2014-10-31

    The Yb{sub 3}Al{sub 5}O{sub 12} (YbAG) crystal is proposed as a matrix of Tm{sup 3+}-doped laser elements for two-micron lasers. A Tm : YbAG crystal of high optical quality is grown by the Czochralski method and its spectral and luminescent characteristics are studied. The luminescence decay time for the upper laser level {sup 3}F{sub 4} is measured to be 4.7 ms. Lasing in this crystal pumped by a 1.678-μm fibre laser is obtained at a wavelength of 2.02 μm for the first time. The total and slope efficiencies of the laser at room temperature and an output power up to 330 mW reach 33% and 41%, respectively. (lasers)

  12. High efficient 1.56 microm laser operation of Czochralski grown Er:Yb:Sr3Y2(BO3)4 crystal.

    PubMed

    Huang, Jianhua; Chen, Yujin; Lin, Yanfu; Gong, Xinghong; Luo, Zundu; Huang, Yidong

    2008-10-27

    An Er:Yb:Sr(3)Y(2)(BO(3))(4) crystal doped with 0.9 at.% Er(3+) and 18.6 at.% Yb(3+) ions was grown by the Czochralski method. End-pumped by diode laser at 970 nm in a hemispherical cavity, 1.3 W quasi-cw laser output around 1.56 microm was achieved in a 1.1-mm-thick Z-cut Er:Yb:Sr(3)Y(2)(BO(3))(4) crystal when the transmission of output coupler is 1.5%. The absorbed pump threshold and slop efficiency of the laser are 4.26 W and 20%, respectively. This crystal has flat and broad gain curve peaked around 1.56 microm, which shows that it is also a potential gain medium for tunable and short pulse lasers.

  13. Peculiarities of thermoelectric half-Heusler phase formation in Gd-Ni-Sb and Lu-Ni-Sb ternary systems

    NASA Astrophysics Data System (ADS)

    Romaka, V. V.; Romaka, L.; Horyn, A.; Rogl, P.; Stadnyk, Yu; Melnychenko, N.; Orlovskyy, M.; Krayovskyy, V.

    2016-07-01

    The phase equilibria in the Gd-Ni-Sb and Lu-Ni-Sb ternary systems were studied at 873 K by X-ray and metallographic analyses in the whole concentration range. The interaction of the elements in the Gd-Ni-Sb system results the formation of five ternary compounds at investigated temperature: Gd5Ni2Sb (Mo5SiB2-type), Gd5NiSb2 (Yb5Sb3-type), GdNiSb (MgAgAs-type), Gd3Ni6Sb5 (Y3Ni6Sb5-type), and GdNi0.72Sb2 (HfCuSi2-type). At investigated temperature the Lu-Ni-Sb system is characterized by formation of the LuNiSb (MgAgAs-type), Lu5Ni2Sb (Mo5SiB2-type), and Lu5Ni0.56Sb2.44 (Yb5Sb3-type) compounds. The disordering in the crystal structure of half-Heusler GdNiSb and LuNiSb was revealed by EPMA and studied by means of Rietveld refinement and DFT modeling. The performed electronic structure calculations are in good agreement with electrical transport property studies.

  14. Ionic conductivity of crystallization products of Ba1- x Yb x F2 + x melts ( x = 0.1, 0.2, 0.25)

    NASA Astrophysics Data System (ADS)

    Sorokin, N. I.; Sul'yanova, E. A.; Sobolev, B. P.

    2016-05-01

    The ionic conductivity σ of the crystallization products of Ba1 - x Yb x F2 + x melts with 10, 20 and 25 mol % YbF3 has been studied. A Ba0.9Yb0.1F2.1 sample is a solid solution with the CaF2 structure type, sp. gr. Fmoverline 3 m. A Ba0.8Yb0.2F2.2 sample contains two cubic forms with sp. gr. Fmoverline 3 m and Pmoverline 3 m. The σ values for Ba0.9Yb0.1F2.1 and Ba0.8Yb0.2F2.2 coincide and are equal to 3 × 10-5 S/cm at 500 K. A Ba0.75Yb0.25F2.25 sample is heterogeneous, despite its monolithic nature and transparency. A greater part of its volume has a cubic lattice with sp. gr. Pmoverline 3 m, while the smaller part is a phase crystallizing in the orthorhombic system. A change of composition from x = 0.2 to 0.25 leads to a change in the symmetry group and type of the cluster defects in the Ba1 - x Yb x F2 + x phase. The sp. gr. Fmoverline 3 m is replaced by the sp. gr. Pmoverline 3 m, and octahedral‒cubic {Ba8Yb6F69} clusters are transformed into "inverse" octahedral‒cubic {Yb8Ba6F71} clusters. These changes in the defect structure lead to an increase in conductivity by a factor of about 100. The fluorine-ionic conductivity of Ba0.75Yb0.25F2.25 is 2.5 × 10-3 S/cm at 500 K. This value exceeds the conductivity of Ba0.69La0.31F2.31 crystal by a factor of 15 (Ba0.69La0.31F2.31 has the best conducting properties among the fluorite phases of the Ba1 - x R x F2 + x family, for which σ was found to increase with a decrease in the atomic number of rare earth element (REE)).

  15. Diode-pumped femtosecond oscillators using ultra-broad-band Yb-doped crystals and modelocked using low-temperature grown or ion implanted saturable-absorber mirrors

    NASA Astrophysics Data System (ADS)

    Druon, F.; Valentine, G. J.; Chénais, S.; Raybaut, P.; Balembois, F.; Georges, P.; Brun, A.; Kemp, A. J.; Birkin, D. J. L.; Sibbett, W.; Mohr, S.; Kopf, D.; Burns, D.; Courjaud, A.; Hönninger, C.; Salin, F.; Gaumé, R.; Aron, A.; Aka, G.; Viana, B.; Clerc, C.; Bernas, H.

    2002-12-01

    Femtosecond modelocked lasers using new ytterbium-doped borate crystals (Yb:Sr3Y(BO3)3, Yb:Ca4GdO(BO3)3 and Yb:Ca4YO(BO3)3) are demonstrated. Pulse duration as short as 69 fs has been obtained. To modelock such lasers, fast saturable absorbers need to be used. Two different types of fast saturable absorbers have been studied: low-temperature-grown semiconductor mirrors (SESAM) and high-energy-ion-implanted semiconductor Bragg reflectors (SBR). We demonstrated, for the first time to our knowledge, that ion-implanted SBR can be used to modelock oscillators using Yb-doped materials.

  16. Plasmon enhanced energy-transfer up-conversion in Yb3+-Er3+ co-doped LiNbO3 crystal

    NASA Astrophysics Data System (ADS)

    Hernández-Pinilla, D.; Molina, P.; Plaza, J. L.; Bausá, L. E.; Ramírez, M. O.

    2017-01-01

    We have analyzed the effect of linear chains of metallic Ag nanoparticles on the optical properties of a periodically poled Yb3+-Er3+ co-doped LiNbO3 crystal. By exploiting the broad plasmonic response supported by linear chains of strongly coupled Ag nanoparticles, we demonstrate a 50% of enhancement of the up-converted Er3+ emission under excitation in the f-f transition of Yb3+ ions. The observed intensification is explained in terms of the broad plasmonic spectral response supported by the Ag chains, which overlaps both the Er3+ visible emissions and the Yb3+ absorption band, and the two-photon character of the Yb3+ → Er3+ energy-transfer up-conversion process. The results are of interest for applications involving luminescence up-conversion such as sensing, solar energy conversion, biological imaging or solid-state nanolasers.

  17. Magnetism in the KBaRE(BO3)2 (RE  =  Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu) series: materials with a triangular rare earth lattice

    NASA Astrophysics Data System (ADS)

    Sanders, M. B.; Cevallos, F. A.; Cava, R. J.

    2017-03-01

    We report the magnetic properties of compounds in the KBaRE(BO3)2 family (RE  =  Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb), materials with a planar triangular lattice composed of rare earth ions. The samples were analyzed by x-ray diffraction and crystallize in the space group R-3m. Physical property measurements indicate the compounds display predominantly antiferromagnetic interactions between spins without any signs of magnetic ordering above 1.8 K. The ideal 2D rare earth triangular layers in this structure type make it a potential model system for investigating magnetic frustration in rare-earth-based materials.

  18. Electronic structure of Lu1-xLaxVO3 single crystals using soft x-ray spectroscopy

    NASA Astrophysics Data System (ADS)

    Chen, Bo; Laverock, Jude; McNulty, James; Newby, Dave; Smith, Kevin; Glans, Anders; Guo, Jinghua; Balakrishnan, Geetha; Singh, Ravi

    2012-02-01

    The rare-earth vanadates, RVO3, offer a rich phase diagram of both orbital and spin ordering phenomena, stemming from their two-fold occupation of the three-fold degenerate V t2g orbitals. It has been discussed that, in RVO3, which shows the t2g orbital ordering, the Jahn-Teller coupling suppression is much weaker than that in the eg electron systems. In order to address the orbital ordering effects, we report soft x-ray measurements of Lu1-xLaxVO3 single crystals, which approach both the smallest and largest rare-earth ionic sizes. X-ray absorption spectroscopy and x-ray emission spectroscopy, which reveal both the unoccupied and occupied partial density of states, are employed to observe the changes in the V 3d and O 2p states, across the orbital ordering transitions and R-site ionic radii. Also, resonant inelastic x-ray scattering is applied to probe the O 2p-V 3d* charge transfer excitations and V 3d-3d* transitions. Together, these complementary techniques provide a picture of the electronic structure of Lu1-xLaxVO3 to test the role of the orbital ordering during phase transitions with varying rare-earth ionic sizes.

  19. Order-to-disorder phase transformation in ion irradiated uranium-bearing delta-phase oxides RE{sub 6}U{sub 1}O{sub 12} (RE=Y, Gd, Ho, Yb, and Lu)

    SciTech Connect

    Tang, M.; Holliday, K.S.; Jiang, C.; Valdez, J.A.; Uberuaga, B.P.; Dickerson, P.O.; Dickerson, R.M.; Wang, Y.; Czerwinski, K.R.; Sickafus, K.E.

    2010-04-15

    Polycrystalline uranium-bearing compounds Y{sub 6}U{sub 1}O{sub 12}, Gd{sub 6}U{sub 1}O{sub 12}, Ho{sub 6}U{sub 1}O{sub 12}, Yb{sub 6}U{sub 1}O{sub 12}, and Lu{sub 6}U{sub 1}O{sub 12} samples were irradiated with various ions species (300 keV Kr{sup ++}, 400 keV Ne{sup ++}, and 100 keV He{sup +}) at cryogenic temperature ({approx}100 K), and the microstructures were examined following irradiation using grazing incidence X-ray diffraction and transmission electron microscopy. The pristine samples are characterized by an ordered, fluorite derivative structure, known as the delta phase. This structure possesses rhombohedral symmetry. Amorphization was not observed in any of the irradiated samples, even at the highest dose {approx}65 dpa (displacement per atom). On the other hand, some of these compounds experienced an order-to-disorder (O-D) phase transformation, from an ordered rhombohedral to a disordered fluorite structure, at ion doses between 2.5 and 65 dpa, depending on ion irradiation species. Factors influencing the irradiation-induced O-D transformation tendencies of these compounds are discussed in terms of density functional theory calculations of the O-D transformation energies. - Graphical abstract: The different order-to-disorder (O-D) phase transformation tendencies in irradiated uranium-bearing delta-phase RE{sub 6}U{sub 1}O{sub 12} compounds (Y{sub 6}U{sub 1}O{sub 12}, Gd{sub 6}U{sub 1}O{sub 12}, Ho{sub 6}U{sub 1}O{sub 12}, Yb{sub 6}U{sub 1}O{sub 12}, and Lu{sub 6}U{sub 1}O{sub 12}) are revealed by grazing incidence X-ray diffraction and transmission electron microscopy measurements, and theoretical simulations of the O-D transformation energies, performed using DFT, also support our experimental results.

  20. Crystal chemistry and spectroscopic properties of ScAuSn, YAuSn, and LuAuSn

    NASA Astrophysics Data System (ADS)

    Sebastian, C. Peter; Eckert, Hellmut; Rayaprol, Sudhindra; Hoffmann, Rolf-Dieter; Pöttgen, Rainer

    2006-05-01

    The stannides ScAuSn, YAuSn, and LuAuSn were synthesized as single phase materials from the elements via arc-melting. All samples were characterized by X-ray diffraction on powders and single crystals: MgAgAs type, F4¯3m, a=641.94(12) pm, wR2=0.035, 85 F values, 5 variables for ScAuSn, a=656.52(8) pm, wR2=0.029, 89 F values, 5 variables for LuAuSn, and NdPtSb type, P6mc, a=463.55(16), c=737.26(15) pm, wR2=0.057, 233 F values, 11 variables for YAuSn. The gold and tin atoms in ScAuSn and LuAuSn build up three-dimensional [AuSn] networks of corner-sharing AuSn 4/4 tetrahedra (278 and 284 pm Au sbnd Sn in ScAuSn and LuAuSn, respectively) similar to the blende type structure. The scandium atoms fill octahedral voids formed by the tin substructure. In contrast, the [AuSn] network of YAuSn is two-dimensional. The gold and tin atoms build up layers of puckered [Au 3Sn 3] hexagons with intralayer Au sbnd Sn distances of 277 pm, while the interlayer Au sbnd Sn distances of 297 pm are much longer. In every other layer the [Au 3Sn 3] hexagons are rotated by 60°. The layers are separated by the yttrium atoms. Spectroscopic measurements indicate significant differences in the chemical bonding properties: As revealed by both 119Sn Mössbauer spectroscopy and 119Sn solid-state NMR data, the local electronic environment at the tin site is more anisotropic in YAuSn as compared to the other materials, which feature tin on a site with cubic point symmetry. In ScAuSn, the cubic site symmetry of the scandium position is reflected by a single sharp line in the 45Sc solid-state NMR spectrum.

  1. UV-visible luminescence properties of the broad-band Yb:CALGO laser crystal

    NASA Astrophysics Data System (ADS)

    Jaffres, A.; Sharma, S. K.; Loiseau, P.; Viana, B.; Doualan, J. L.; Moncorgé, R.

    2015-03-01

    Yb:CALGO is now recognized to exhibit outstanding properties for the production of high-power and ultra-short laser pulses in the near infrared spectral range. However, various UV-visible absorption bands can be also observed due to different types of charge transfer mechanisms. Some of them are assigned to the formation of color centers due to small polarons and others to O2-→Yb3+ ligand-to-metal charge transfer (LMCT) transitions. The former can be removed by using adequate thermal treatments. The latter are intrinsic and they are very intense with cross sections of about two orders of magnitude larger that the near infrared ones. In fact, such LMCT absorption bands are responsible for relatively large changes of ionic polarizabilities and to non-negligible pseudo-nonlinear changes of refractive indices which should certainly affect the laser properties of Yb:CALGO at high pump power levels.

  2. Minimization of temperature for laser cooling of Yb-ion-doped crystals.

    PubMed

    Ivanov, Andrei; Rozhdestvensky, Yuriy; Perlin, Evgeniy

    2016-10-01

    In this paper, quantum mechanical calculations of cooling characteristics for the Yb3+:  YLF system with use of the vibronic model of laser cooling are presented. Dynamics of the laser cooling process for the seven-level system of an Yb ion is described by the density-matrix formalism. Dependences of the cooling characteristics on the pump intensity are obtained for various temperatures and absorption coefficients of impurity ions. It is shown that the pump intensity, at which the net cooling power has a maximum, depends on temperature. Thus, choosing the intensities, which correspond to the net cooling power maximum over the entire temperature range, we achieve a lower sample temperature at a shorter time than in the case of using a constant intensity throughout the cooling process. Calculations are performed for the parameters of the Yb3+:YLF system.

  3. Upconversion emission properties of CeO2: Tm3+, Yb3+ inverse opal photonic crystals

    NASA Astrophysics Data System (ADS)

    Cheng, Gong; Wu, Hangjun; Yang, Zhengwen; Liao, Jiayan; Lai, Shenfeng; Qiu, Jianbei; Song, Zhiguo

    2014-10-01

    The ordered and disordered templates were assembled by vertical deposition of polystyrene microspheres. The CeO2: Tm3+, Yb3+ precursor solution was used to infiltrate into the voids of the ordered and disordered templates, respectively. Then the ordered and disordered templates were calcined at 950°C in an air furnace, and the CeO2: Tm3+, Yb3+ inverse opals were obtained. The upconversion emissions from CeO2: Tm3+, Yb3+ inverse opals were suppressed due to the photon trapping caused by Bragg reflection of lattice planes when the upconversion emission band was in the range of the photonic band gaps in the inverse opals.

  4. Tunable multicolor and white-light upconversion luminescence in Yb3+/Tm3+/Ho3+ tri-doped NaYF4 micro-crystals.

    PubMed

    Lin, Hao; Xu, Dekang; Teng, Dongdong; Yang, Shenghong; Zhang, Yueli

    2015-09-01

    NaYF4 micro-crystals with various concentrations of Yb(3+) /Tm(3+) /Ho(3+) were prepared successfully via a simple and reproducible hydrothermal route using EDTA as the chelating agent. Their phase structure and surface morphology were studied using powder X-ray diffraction (XRD) and scanning electron microscopy (SEM). The XRD patterns revealed that all the samples were pure hexagonal phase NaYF4. SEM images showed that Yb(3+)/Tm(3+)/Ho(3+) tri-doped NaYF4 were hexagonal micro-prisms. Upconversion photoluminescence spectra of Yb(3+)/Tm(3+)/Ho(3+) tri-doped NaYF4 micro-crystals with various dopant concentrations under 980 nm excitation with a 665 mW pump power were studied. Tunable multicolor (purple, purplish blue, yellowish green, green) and white light were achieved by simply adjusting the Ho(3+) concentration in 20%Yb(3+)/1%Tm(3+)/xHo(3+) tri-doped NaYF4 micro-crystals. Furthermore, white-light emissions could be obtained using different pump powers in 20%Yb(3+)/1%Tm(3+)/1%Ho(3+) tri-doped NaYF4 micro-crystals at 980 nm excitation. The pump power-dependent intensity relationship was studied and relevant energy transfer processes were discussed in detail. The results suggest that Yb(3+)/Tm(3+) Ho(3+) tri-doped NaYF4 micro-crystals have potential applications in optoelectronic devices such as photovoltaic, plasma display panel and white-light-emitting diodes. Copyright © 2014 John Wiley & Sons, Ltd.

  5. CW and passively Q-switched laser performance of Nd:Lu2SiO5 crystal

    NASA Astrophysics Data System (ADS)

    Xu, Xiaodong; Di, Juqing; Zhang, Jian; Tang, Dingyuan; Xu, Jun

    2016-01-01

    We demonstrated an efficient and controllable dual-wavelength continuous-wave (CW) laser of Nd:Lu2SiO5 (Nd:LSO) crystal. The maximum output power was 3.02 W at wavelength of 1075 nm and 1079 nm, and with increasing of absorbed pump power, the ratio of 1079 nm laser rose. The slope efficiency of 65.6% and optical-to-optical conversion efficiency of 63.3% were obtained. The passively Q-switched laser properties of Nd:LSO were investigated for the first time. The shortest pulse, maximum pulse energy and peak power were 11.58 ns, 29.05 μJ and 2.34 kW, respectively.

  6. Cut-off analysis of 19-cell Yb-doped double-cladding rod-type photonic crystal fibers.

    PubMed

    Poli, F; Coscelli, E; Alkeskjold, T T; Passaro, D; Cucinotta, A; Leick, L; Broeng, J; Selleri, S

    2011-05-09

    Yb-doped double-cladding large mode area rod-type photonic crystal fibers are a key component for power scaling in fiber laser systems. Recently, designs with 19-cell core defect, that is with 19 missing air-holes in the center of the photonic crystal cladding, have been proposed, with reported core diameter up to 100 μm. In this paper an analysis of the cut-off wavelength of the first high-order mode in such low-NA fibers is reported, accounting for different approaches for the definition of the cladding effective index. Results have shown that taking into account the finite fiber cross-section and considering the first cladding mode of the actual fiber is mandatory to obtain a correct estimate of the cut-off wavelength.

  7. Yb3+-doped LiBi(WO4)2 single crystals fibers grown by micro-pulling down technique and characterization

    NASA Astrophysics Data System (ADS)

    Rekik, B.; Derbal, M.; Lebbou, K.; Benammar, M. E. A.

    2016-10-01

    The Yb3+ doped LiBi(WO4)2 fibers single crystals have been pulled using the micro-pulling down technique (μ-PD) with controlled fiber diameter and under stationary stable growth conditions. The corresponding crystallization interface was flat, with meniscus length equal to the fiber radii. The pulling rate used was in the range of 2-6 mm h-1. We have determined the monophased field of LiBi1-xYbx(WO4)2 and observed that the lattice parameters decrease as a function of Yb3+ substitution in Bi3+ sites. The structural characterization has been studied by X-ray diffraction (XRD), X-ray fluorescence (XRF) method and Raman spectroscopy. We also performed micro-luminescence characterizations and drawn the decay time for both of the 1 at% (Yb3+) doped LiBi(WO4)2 fiber and powders.

  8. Infrared (1.2-1.6 microm) luminescence in Cr4+:Yb3Al5O12 single crystal with 940 nm diode pumping.

    PubMed

    Xu, Xiaodong; Zhao, Zhiwei; Song, Pingxin; Zhou, Guoqing; Xu, Jun; Deng, Peizhen; Bourdet, Gilbert; Chanteloup, Jean Christophe; Zou, Ji-Ping; Fulop, Annabelle

    2005-09-01

    Infrared (1.2-1.6 microm) luminescence in a ytterbium aluminium garnet (YbAG) crystal, doped with Cr (0.05at.%) ions, was investigated under CW laser diode pumping (lambda=940 nm). The Cr4+ emission band was observed with its peak at 1.34 microm and measured to be about 1.3 times with respect to Yb3+ IR luminescence (lambda=1.03 microm). We demonstrate that for the excitation wavelength of 940 nm Yb3+ ions act as sensitizers of the 3B2(3T2)-3B1(3A2) emission of Cr4+ ions. This crystal is promising as a high-efficient system for tunable laser (1.2-1.6 microm) output.

  9. Photoluminescence and dielectric properties of pure/Yb-doped SrZrO3 crystals

    NASA Astrophysics Data System (ADS)

    Zhang, Lulu; Wang, Jilin; Peng, Daijiang; Long, Fei; Mo, Shuyi; Wu, Yi; Zou, Zhengguang

    2017-05-01

    High quality SrZrO3 nanocubes have been successfully synthesized via a facile hydrothermal method using Sr(NO3)2 and Zr(NO3)4·5H2O as raw materials. Then, the Yb-doped SrZrO3 were also fabricated by solid state reaction using the as-synthesized pure SrZrO3. The phase structure, morphology, composition and specific surface area of the samples were investigated by XRD, FESEM, EDS, TEM, FTIR, Raman and BET techniques. The as-synthesized SrZrO3 nanocubes distributed homogeneously and displayed sharp edges with an average particle size of about 100 nm. In addition, the dielectric loss value of the pure SrZrO3 at 1 MHz was only 0.05 when the temperature rose from 25 °C to 550 °C, indicating a good dielectric property at high temperature. Meanwhile, the band gap of SrZrO3 could be reduced by about 0.3 eV after Yb3+ doping, where Yb3+ mainly occupied Sr2+ position (A site doping). Besides, all of the pure and Yb-doped SrZrO3 samples exhibit violet light emission centered at 423 nm (excited at 372 nm), which was originated from material intrinsic defects.

  10. Syntheses and crystal structures of the rare-earth metal(III) bromide ortho-oxidotungstates(VI) with the formula REBr[WO4] (RE = Y, Gd-Yb)

    NASA Astrophysics Data System (ADS)

    Schustereit, Tanja; Schleid, Thomas; Hartenbach, Ingo

    2015-10-01

    The rare-earth metal(III) bromide ortho-oxidotungstates(VI) with the formula REBr[WO4] crystallize triclinically in space group P 1 bar (a = 689-693, b = 715-728, c = 1074-1107 pm, α = 103-106, β ≈ 108 and γ = 93-95°, Z = 4) for RE = Y, Gd-Yb. Their crystal structure is isotypic with the most examples of the formally analogous lanthanoid(III) bromide oxidomolybdates(VI) REBr[MoO4] with RE = Y, Pr, Nd, Sm, Gd-Lu. It contains two crystallographically different rare-earth metal(III) cations with coordination numbers of seven plus one for (RE1)3+ and seven for (RE2)3+. The (RE1)3+ cations are surrounded by three Br- and four plus one O2- anions forming distorted trigonal dodecahedra, while the (RE2)3+ cations exhibit a coordination environment of one Br- and six O2- anions in the shape of a monocapped trigonal prism. Furthermore, the structure contains two crystallographically independent, isolated tetrahedral [WO4]2- units. All these polyhedra are fused together to form 1 ∞ {REBr[WO4]} chains running along [012]. Since the title compounds, synthesized by solid-state reactions from the underlying binaries, emerge as pure phases according to X-ray powder diffractometry, spectroscopic and magnetic measurements were performed.

  11. Anomalies in the Young modulus at structural phase transitions in rare-earth cobaltites RBaCo{sub 4}O{sub 7} (R = Y, Tm-Lu)

    SciTech Connect

    Kazei, Z. A. Snegirev, V. V.; Andreenko, A. S.; Kozeeva, L. P.

    2011-08-15

    The elastic properties of rare-earth cobaltites RBaCo{sub 4}O{sub 7} (R = Y, Tm-Lu) have been experimentally studied in the temperature range of 80-300 K. The strong softening of the Young modulus {Delta}E(T)/E{sub 0} Almost-Equal-To -(0.1-0.2) of cobaltites with Lu and Yb ions has been revealed, which is due to the instability of the crystal structure upon cooling and is accompanied by an inverse jump at the second-order structural phase transition. The softening of the Young modulus and the jump at the phase transition decrease by an order of magnitude and the transition temperature T{sub s} and hysteresis {Delta}T{sub s} increase from a compound with Lu to that with Tm. A large softening of the Young modulus at the structural transition in Lu- and Yb cobaltites indicates that the corresponding elastic constant goes to zero, whereas this constant in Tm cobaltite is not a 'soft' mode of the phase transition. It has been found that the structural phase transition in Lu- and Yb cobaltites is accompanied by a large absorption maximum at the phase transition point and an additional maximum in the low-temperature phase and absorption anomalies in Tm cobaltite is an order of magnitude smaller.

  12. Simultaneous tri-wavelength laser operation at 916, 1086, and 1089 nm of diode-pumped Nd:LuVO4 crystal

    NASA Astrophysics Data System (ADS)

    Shen, Bingjun; Jin, Lihong; Zhang, Jiajia; Tian, Jian

    2016-09-01

    We report a diode-pumped continuous-wave tri-wavelength Nd:LuVO4 laser operating at 916, 1086, and 1089 nm. A theoretical analysis has been introduced to determine the threshold conditions for simultaneous tri-wavelength laser operation. Using a T-shaped cavity, we realized efficient tri-wavelength operation at 4F3/2  →  4I9/2 and 4F3/2  →  4I11/2 transitions for Nd:LuVO4 crystal, simultaneously. The maximum output power was 2.8 W, which included 916, 1086, and 1089 nm, and the optical conversion efficiency was 15.1%. To our knowledge, this is the first work that realizes simultaneous tri-wavelength Nd:LuVO4 laser operation.

  13. Laser performance of in-band pumped Er : LiYF{sub 4} and Er : LiLuF{sub 4} crystals

    SciTech Connect

    Gorbachenya, K N; Kisel, V E; Yasukevich, A S; Kuleshov, N V; Kurilchik, S V; Nizamutdinov, A S; Korableva, S L; Semashko, V V

    2016-02-28

    Spectroscopic properties of Er : LiLuF{sub 4} and Er : LiYF{sub 4} crystals in the spectral region near 1.5 μm and the lasing characteristics of these crystals under in-band pumping at a wavelength of 1522 nm are studied. With the Er : LiLuF{sub 4} crystal, the maximum slope efficiency with respect to the absorbed pump power was 44% at a wavelength of 1609 nm. Continuous-wave operation of an inband pumped Er : LiYF{sub 4} laser is obtained for the first time. The output power at a wavelength of 1606 nm was 58 mW with a slope efficiency of 21%. (lasers)

  14. Measurement of the sign and magnitude of the electric field gradients at Re and Os nuclei as impurities in a hexagonal Lu single crystal

    SciTech Connect

    Ernst, H.; Hagn, E.; Zech, E.

    1980-09-01

    The nuclear orientation technique has been applied to dilute alloys of /sup 182/Re ( j/sup ..pi../=2/sup +/) and /sup 183/Os ( j/sup ..pi../=9/2/sup +/) nuclei in a hexagonal Lu single crystal, the activities being produced in situ via the heavy-ion-induced nuclear compound reaction (/sup 12/C, xn) with x=4,5. From the ..gamma.. anisotropy at temperatures down to 6 mK the quadrupole interaction frequencies of /sup 182/ReLu and /sup 183/OsLu have been determined as +311(24) MHz and +403(20) MHz, respectively. The electric field gradients (EFG) are deduced to be eq(ReLu)=+6.8(6) x 10/sup 17/ V/cm/sup 2/ and eq(OsLu)=+5.3(5) x 10/sup 17/ V/cm/sup 2/. The positive sign in both cases indicates that the direction of the EFG at the impurity sites is fixed by the properties of the host lattice.

  15. Growth, Thermal and Spectral Properties of Er3+-Doped and Er3+/Yb3+-Codoped Li3Ba2La3(WO4)8 Crystals

    PubMed Central

    Xiao, Bin; Lin, Zhoubin; Zhang, Lizhen; Huang, Yisheng; Wang, Guofu

    2012-01-01

    This paper reports the growth and spectral properties of Er3+-doped and Er3+/Yb3+-codoped Li3Ba2La3(WO4)8 crystals. The Er3+: Li3Ba2La3(WO4)8 crystal with dimensions of 56 mm×28 mm×9 mm and Er3+/Yb3+: Li3Ba2La3(WO4)8 crystal with dimensions of 52 mm×24 mm×8 mm were obtained by the top-seeded solution growth (TSSG) method. Thermal expansion coefficients and thermal conductivity of both crystals were measured. The spectroscopic characterizations of both crystals were investigated. The spectroscopic analysis reveals that the Er3+/Yb3+: Li3Ba2La3(WO4)8 crystal has much better optical properties than the Er3+: Li3Ba2La3(WO4)8 crystal, thus it may become a potential candidate for solid-state laser gain medium material. PMID:22808214

  16. [Crystal structure and upconversion emission of Yb3+/Er(3+) -co-doped NaYF4 nanocrystals].

    PubMed

    Yao, Li-Li; Luo, Li; Dong, Guo-Shuai; Wang, Yin-Hai

    2013-11-01

    Yb3+/EP(3+) -co-doped cubic NaYF4 and Yb3+/Er3+/Gd(3+) -tri-doped hexagonal NaYF4 nanocrystals were synthesized by a modified coprecipitation method with ethylenediamine tetraacetic acid (EDTA) as chelating agent. The samples' morphology, crystal phase and upconversion emission were measured with transmission electron microscope (TEM), X-ray diffraction patterns (XRD) and upconversion luminescence spectrum. TEM and XRD results showed that the phase transition from cubic to hexagonal was promoted through Gd3+ doping. It has been reported that the upconversion efficiency of hexagonal NaYF4 is higher than that of cubic NaYF4, however, the effect of crystal phase on upconversion luminescence has not been well understood. This work focuses analysis of measurement results to compare the effect of, crystal phase on the crystal field energy splitting and upconversion emission intensity as well as emission color, and a mechanism of luminescence enhancement and color tunability are revealed. Strong visible upconversion luminescence can be seen clearly by the naked eyes in both cubic phase and hexagonal phase samples upon excitation by a 980 nm laser diode with power of 10 mW, consisting of green emissions centered at around 525/550 nm originating from the transitions of 2H11/2/4 S3/2 --> 4 I15/2 and red emission at about 657 nm from 4F9/2 to 4 I15/2 of Er3+ ions respectively. In comparison to cubic sample, the hexagonal phase sample presented much stronger and sharper upconversion luminescence, whose emission efficiency was enhanced 10 times with an additional transition of 2 H9/2 --> 4I13/2 at 557 nm, furthermore, the intensity ratio of red to green emission increased from 2 :1 to 3 : 1. Doping NaYF4 nanocrystals with Gd3+ ions induced the hexagonal-to-cubic phase transition and thus decreased the crystal symmetry, consequently increased absorption cross-section and 4f-4f transition probabilities by relaxing forbidden selection rules, resulting in stronger emission. In the

  17. Peculiarities of thermoelectric half-Heusler phase formation in Gd-Ni-Sb and Lu-Ni-Sb ternary systems

    SciTech Connect

    Romaka, V.V.; Romaka, L.; Horyn, A.; Rogl, P.; Stadnyk, Yu; Melnychenko, N.; Orlovskyy, M.; Krayovskyy, V.

    2016-07-15

    The phase equilibria in the Gd–Ni–Sb and Lu-Ni-Sb ternary systems were studied at 873 K by X-ray and metallographic analyses in the whole concentration range. The interaction of the elements in the Gd–Ni–Sb system results the formation of five ternary compounds at investigated temperature: Gd{sub 5}Ni{sub 2}Sb (Mo{sub 5}SiB{sub 2}-type), Gd{sub 5}NiSb{sub 2} (Yb{sub 5}Sb{sub 3}-type), GdNiSb (MgAgAs-type), Gd{sub 3}Ni{sub 6}Sb{sub 5} (Y{sub 3}Ni{sub 6}Sb{sub 5}-type), and GdNi{sub 0.72}Sb{sub 2} (HfCuSi{sub 2}-type). At investigated temperature the Lu-Ni-Sb system is characterized by formation of the LuNiSb (MgAgAs-type), Lu{sub 5}Ni{sub 2}Sb (Mo{sub 5}SiB{sub 2}-type), and Lu{sub 5}Ni{sub 0.56}Sb{sub 2.44} (Yb{sub 5}Sb{sub 3}-type) compounds. The disordering in the crystal structure of half-Heusler GdNiSb and LuNiSb was revealed by EPMA and studied by means of Rietveld refinement and DFT modeling. The performed electronic structure calculations are in good agreement with electrical transport property studies. - Graphical abstract: Crystal structure model and electron localization function of Lu{sub 5}Ni{sub 2}Sb. Display Omitted - Highlights: • Gd-Ni-Sb and Lu-Ni-Sb phase diagrams were constructed at 873 K. • GdNiSb and LuNiSb are characterized by disordered crystal structure. • Crystal structure optimization with DFT calculations confirmed crystal structure disorder in GdNiSb and LuNiSb.

  18. Sequential energy transfer up-conversion process in Yb3+/Er3+:SrMoO4 crystal.

    PubMed

    Zhuang, Renzhong; Wang, Guofu

    2016-04-04

    This paper reports the dynamic characteristics of sequential energy transfer up-conversion processes in Yb3+/Er3+:SrMoO4 crystal. A general method based on the emission intensity has been developed to calculate the nonradiative decay rate. A new macroscopic theory has been developed to calculate the energy transfer parameters based on the crystal structure. According to both new calculating methods, the spectral parameters of Yb3+/Er3+:SrMoO4 crystal were calculated, such as up-conversion luminescent quantum efficiencies and threshold pump powers. Both calculating methods may be applied to calculate the spectral parameters of the laser crystal materials.

  19. [Spectroscopic analysis of Er3+ in Er3+ /Yb3+ co-doped LiNbO3 crystal].

    PubMed

    Wang, Dun-Chun; Zhang, De-Long; Cui, Yu-Ming; Chen, Cai-He

    2005-12-01

    At room temperature, alpha-polarized absorption spectra of as-grown and annealed Er3+/Yb3+ co-doped, Z-cut LiNbO3 single crystals, grown by using Czochralski method, were measured in the wavelength range of 300-1 650 nm. The spectroscopic properties of Er3+ were analysed by using Judd-Ofelt theory. The experimental values of the electron transition strengths of several major transitions from the ground state to excited-state manifolds were evaluated from the measured integrated absorption coefficients of Er3+. The Judd-Ofelt parameters were determined by using least square method. According to the fitted Judd-Ofelt parameters, the spontaneous emission rates, the fluorescence branch ratios from the excited-state manifolds J to the lower-lying manifolds J', as well as the radiative lifetimes of the excited states were numerically calculated. In addition, Yb3+ co-doping and thermal anneal effects on the spectroscopic properties of Er3+ were also considered in this work.

  20. Spectroscopic properties and pulsed laser performance of thulium-doped (Lu,Y)3Al5O12 mixed crystal

    NASA Astrophysics Data System (ADS)

    Zhao, Yongguang; Zhou, Wei; Xu, Xiaodong; Shen, Deyuan

    2016-12-01

    In this paper, we describe a thulium-doped (Lu,Y)3Al5O12 mixed crystal that was designed and grown to achieve a large pulse energy in Q-switched laser operation. Its absorption cross-sections at 781.3 nm and 1629.2 nm were calculated to be 3.4 × 10-21 cm2 and 5 × 10-21 cm2, respectively, and the emission cross-section at 2018.3 nm was calculated to be 1.92 × 10-21 cm2. The highest single pulse energy of 1.4 mJ near 2.02 μm was realized in an actively Q-switched solid-state laser, and further power scaling was just limited by the damage of the crystal coating. Based on the calculated spectrum parameters, theoretical simulation of the single pulse energy that considering the cross-relaxation process was proposed, which was well consistent with the experimental results.

  1. Structural characterization of Lu{sub 1.8}Y{sub 0.2}SiO{sub 5} crystals

    SciTech Connect

    Chiriu, Daniele; Faedda, Nicola; Lehmann, Alessandra Geddo; Ricci, Pier Carlo; Anedda, Alberto; Desgreniers, Serge; Fortin, Emery

    2007-08-01

    The structural and vibrational properties of Lu{sub 1.8}Y{sub 0.2}SiO{sub 5} (LYSO) single crystals were investigated by means of Raman spectroscopy and x-ray diffraction measurements. Unit cell parameters and bond lengths were determined by Rietveld refinement of the collected x-ray diffraction powder spectra. By comparison with the vibrational spectra of the parent compounds Lu{sub 2}SiO{sub 5} and Y{sub 2}SiO{sub 5} and by using polarized Raman measurements, we propose the assignment of the principal vibrational modes of LYSO crystals. The strict connection of Raman spectra of the LYSO solid solution and of the pure lutetium and yttrium crystals, as well as the analysis of the polarized measurements, confirms that LYSO structure adopts the C2/c space group symmetry. The structural analogies of LYSO with the pure compound Lu{sub 2}SiO{sub 5} are further shown by means of high pressure Raman spectroscopy, and the possibility of considering the LYSO crystal analogous to the LSO structure with a tensile stress between 0.25 and 0.80 GPa is discussed.

  2. Magnetic remanence in Yb{sub 14−x}RE{sub x}MnSb{sub 11} (RE=Tb, Dy, Ho) single crystals

    SciTech Connect

    Grebenkemper, Jason H.; Hu, Yufei; Abdusalyamova, M.N.; Makhmudov, F.A.

    2016-06-15

    Single crystals of Yb{sub 14−x}RE{sub x}MnSb{sub 11} (x~0.1, 0.4; RE = Tb, Dy, Ho) have been prepared as a solid solution by Sn flux reactions of the elements. They crystallize in the Ca{sub 14}AlSb{sub 11} structure type in the I4{sub 1}/acd space group. The RE{sup 3+}preferentially substitutes on the Yb(1) site which is the smallest volume Yb containing polyhedron. In the case of Ho{sup 3+}, a small amount of Ho{sup 3+} also substitutes on the Yb(4) site. The ferromagnetic ordering temperature of Yb{sub 14}MnSb{sub 11} is reduced from 53 K to 41 K as x increases and dependent on the identity of the RE. This is attributed to the reduction in carriers and reduced screening of the Mn{sup 2+} local moment. The effective moments, μ{sub eff,} agree well with the calculated moments assuming the RE substitutes as a trivalent cation. The largest coercive field is observed for RE = Dy (1000 Oe). For the maximum x of Yb{sub 14−x}RE{sub x}MnSb{sub 11} there are enough carriers for the Ruderman-Kittel-Kasuya-Yosida (RKKY) mechanism of magnetic coupling via conduction electrons to still be valid in describing the ferromagnetic ordering. - Graphical abstract: Field dependent susceptibility loops revealed magnetic remanence in these materials, which has not been previously observed in Yb{sub 14}MnSb{sub 11} compounds. The coercive field increases with the strength of the paramagnetic moment for the substituting rare earth and the amount of the rare earth that is substituted. Display Omitted - Highlights: • Yb{sub 14−x}RE{sub x}MnSb{sub 11} (RE=Tb, Dy, & Ho) were synthesized with x~0.2 and x~0.4. • Tb, Dy, & Ho preferentially substitute on the Yb(1) site. • Samples with the largest x and largest RE moment have the largest coercive field. • There is a split between zero field cooled and field cooled susceptibility.

  3. Octave-spanning spectrum generation in tapered silica photonic crystal fiber by Yb:fiber ring laser above 500 MHz.

    PubMed

    Jiang, Tongxiao; Wang, Guizhong; Zhang, Wei; Li, Chen; Wang, Aimin; Zhang, Zhigang

    2013-02-15

    We report octave-spanning spectrum generated in a tapered silica photonic crystal fiber by a mode-locked Yb:fiber ring laser at a repetition rate as high as 528 MHz. The output pulses from this laser were compressed to 62 fs. By controlling the hole expansion and core diameter, a silica PCF was tapered to 20 cm with an optimal d/Λ ratio of 0.6. Pulses with the energy of 280 pJ and the peak power of 4.5 kW were injected into the tapered fiber and the pulse spectrum was expanded from 500 to 1600 nm at the level of -30 dB.

  4. Yb:YAG single-crystal fiber amplifiers for picosecond lasers using the divided pulse amplification technique.

    PubMed

    Lesparre, Fabien; Gomes, Jean Thomas; Délen, Xavier; Martial, Igor; Didierjean, Julien; Pallmann, Wolfgang; Resan, Bojan; Druon, Frederic; Balembois, François; Georges, Patrick

    2016-04-01

    A two-stage master-oscillator power-amplifier (MOPA) system based on Yb:YAG single-crystal-fiber (SCF) technology and designed for high peak power is studied to significantly increase the pulse energy of a low-power picosecond laser. The first SCF amplifier has been designed for high gain. Using a gain medium optimized in terms of doping concentration and length, an optical gain of 32 dB has been demonstrated. The second amplifier stage designed for high energy using the divided pulse technique allows us to generate a recombined output pulse energy of 2 mJ at 12.5 kHz with a pulse duration of 6 ps corresponding to a peak power of 320 MW. Average powers ranging from 25 to 55 W with repetition rates varying from 12.5 to 500 kHz have been demonstrated.

  5. Yb3+-doped KLu(WO4)2, Nb:RbTiOPO4 and KGd(PO3)4 crystals. Growth, characterization and laser operation

    NASA Astrophysics Data System (ADS)

    Pujol, M. C.; Mateos, X.; Carvajal, J. J.; Solé, R.; Massons, J.; Aguiló, M.; Díaz, F.

    2017-01-01

    Macrodefect-free samples of Yb3+:KLu(WO4)2, Yb3+:Nb:RbTiOPO4 and Yb3+:KGd(PO3)4 laser crystals were grown using the Top Seeded Solution Growth - Slow Cooling technique. Structural and morphological studies related with the three materials were carried out and discussed. The dispersion of the refractive indices was measured and Sellmeier equations were constructed which are valid in the UV-Vis-IR range. The Stark splitting of the two electronic states of trivalent ytterbium was determined and the CW laser generation was demonstrated in these hosts. This paper shows a review of the main results achieved in FiCMA-FiCNA-URV laboratories in relation with these laser materials in the last years.

  6. Determination of the enthalpy of crystallization of the europium, ytterbium, and lutecium iron garnets Eu/sub 3/Fe/sub 5/O/sub 12/, Yb/sub 3/Fe/sub 5/O/sub 12/, and Lu/sub 3/Fe/sub 5/O/sub 12/ and the solid solutions LuEu/sub 2/Fe/sub 5/O/sub 12/, Nd/sub 0. 94/Gd/sub 2. 06/Fe/sub 5/O/sub 12/, Lu/sub 0. 48/Sm/sub 2. 52/Fe/sub 5/O/sub 12/, and La/sub 0. 24/Gd/sub 2. 76/Fe/sub 5/O/sub 12/

    SciTech Connect

    Reznitskii, L.A.; Filippova, S.E.; Leonov, A.V.; Viting, L.M.

    1987-05-01

    The authors have investigated the mechanism and determined the enthalpy of crystallization of x-ray amorphous iron garnets of rare-earth elements and their solid solutions. The authors have established a relation between the mechanism of the solid-phase reaction of formation of the iron garnets and the decrease in the ionic radius of the rare-earth element in the dodecahedral positions. A rise in the temperature during crystallization of amorphous phases facilitates a rapid completion of the reaction in which double oxides with a complex three-sublattice structure are released.

  7. Crystal growth, optical properties, and continuous-wave laser operation of Nd3+-doped Lu2SiO5 crystal

    NASA Astrophysics Data System (ADS)

    Li, D. Z.; Xu, X. D.; Zhou, D. H.; Xia, C. T.; Wu, F.; Xu, J.; Cong, Z. H.; Zhang, J.; Tang, D. Y.

    2011-01-01

    High quality Nd3+-doped Lu2SiO5 (Nd:LSO) crystal has been grown by the Czochralski technique. The cell parameters were analyzed with X-ray diffraction (XRD). Room temperature absorption and fluorescence spectra and fluorescence lifetime of the Nd:LSO crystal were measured and analyzed. The Judd-Ofelt intensity parameters Ω2,4,6 were obtained to be 2.59, 4.90, and 5.96×10-20 cm2, respectively. The absorption and emission cross sections and the branching ratios were calculated. The peak emission cross section is 5.8 and 6.6×10-20 cm2 at 1075 and 1079 nm, respectively, with full width at half maximum (FWHM) of 2.8 and 5.1 nm in turn. Pumped by a laser diode, a maximum 2.54 W continuous-wave laser output has been obtained with a slope efficiency of 32%. All the results show that this crystal is a promising laser material.

  8. Diffraction losses of Nd:YAG and Yb:YAG laser crystals

    NASA Astrophysics Data System (ADS)

    Xie, Wenjie; Kwon, Young; Tam, Siu-Chung; Lam, Yee-Loy

    2001-03-01

    Based on space-dependent rate equations, the lowest threshold input power for a diode end-pumped solid-state laser is obtained for the pump spot size wp→0. However, as the pump beam waist is decreased, the thermally induced effects in the laser rod would be very high. Diffraction losses caused by radial and tangential variations of refractive index have been analyzed and compared for the Nd : YAG and the Yb : YAG at room temperature ( 300 K) and liquid-nitrogen temperature ( 77 K).

  9. Dual-modal upconversion fluorescent/X-ray imaging using ligand-free hexagonal phase NaLuF4:Gd/Yb/Er nanorods for blood vessel visualization.

    PubMed

    Zeng, Songjun; Wang, Haibo; Lu, Wei; Yi, Zhigao; Rao, Ling; Liu, Hongrong; Hao, Jianhua

    2014-03-01

    Visualization of blood vessel of lung can improve the detection of the lung and pulmonary vascular diseases. However, research on visualization of blood vessel of lung using the new generation upconversion nanoprobes is still scarce. Herein, high quality hexagonal phase NaLuF4:Gd/Yb/Er nanorods were synthesized by a simple hydrothermal method through doping Gd(3+). Doping Gd can not only promote the phase transformation from cubic to hexagonal and the shape evolution from microtube to rod-like, but also provide an additional magnetic properties for biomedical application. The as-prepared nanorods were further converted to water solubility by treating with HCl for eliminating the capped oleic acid. The ligand-free nanorods were successfully used for high-contrast upconversion fluorescent bioimaging of HeLa cells. Moreover, the in vivo synergistic upconversion fluorescent and X-ray imaging of nude mice were demonstrated by subcutaneously and intravenously administrated the ligand-free nanorods. The X-ray signals were matched well with the upconversion signal, indicating the successfully synergistic bioimaging. The ex-vivo X-ray and upconversion fluorescent imaging of various organs revealed that the nanorods were mainly accumulated in liver and lung. More importantly, the blood vessel of the lung can be readily visualized when these ligand-free nanorods are intravenously injected. Apart from the synergistic X-ray and upconversion bioimaging, the ligand-free nanorods can also possess excellent paramagnetic property for potential magnetic resonance imaging contrast agent. Our results have demonstrated the enhanced visualization of blood vessel of lung performed by dual-modal bioimaging of X-ray and upconversion fluorescence, revealing the great promise of these nanoprobes in angiography imaging. Such a new technique enables the integration of the two bioimaging techniques by combining their collective strengths and minimizing their shortcomings.

  10. Doping effects on trimerization and magnetoelectric coupling of single crystal multiferroic (Y,Lu)MnO3

    NASA Astrophysics Data System (ADS)

    Choi, Seongil; Sim, Hasung; Kang, Soonmin; Choi, Ki-Young; Park, Je-Geun

    2017-03-01

    Hexagonal RMnO3 is a multiferroic compound with a giant spin–lattice coupling at an antiferromagnetic transition temperature, Lee et al (2008 Nature 451 805). Despite extensive studies over the past two decades, the origin and underlying microscopic mechanism of strong spin–lattice coupling remain very much elusive. In this study, we have tried to address this problem by measuring the thermal expansion and dielectric constant of doped single crystals Y1‑x Lu x MnO3 where x  =  0, 0.25, 0.5, 0.75, and 1.0. From these measurements, we confirm that there is a progressive change in the physical properties with doping. At the same time, all our samples exhibit clear anomalies at T N, even in the samples where x  =  0.5 and 0.75. This is opposed to some earlier ideas, which suggests an unusual doping dependence of the anomaly. Our work reveals yet another interesting facet of the spin–lattice coupling issue in hexagonal RMnO3.

  11. Growth, structure, defects and polarized absorption spectral properties of Er:Yb:YCa{sub 4}O(BO{sub 3}){sub 3} crystals

    SciTech Connect

    Zhong, Degao; Teng, Bing; Kong, Weijin; Zhang, Shiming; Li, Yuyi; Li, Jianhong; Yang, Liting; Cao, Lifeng; Van Smaalen, Sander

    2016-01-15

    YCa{sub 4}O(BO{sub 3}){sub 3} (YCOB) crystals co-doped with 3 at% Er{sup 3+} and 20 at% Yb{sup 3+} were successfully grown by the Czochralski method. X-ray powder diffraction (XRPD) results show that the as-grown Er:Yb:YCOB crystal belongs to the monoclinic system with space group Cm. And the lattice parameters are a=8.076(8) Å, b=16.023(7) Å, c=3.528(4) Å and β=101.15(4)°. Crystal defects were revealed by chemical etching experiments. The density of etch pits, attributed to dislocations and observed on (010) planes, was found to be not uniform along the crystal diameter. The detailed polarized absorption spectra were measured. The polarized absorption cross sections at 977 nm are 1.01×10{sup −20}, 1.22×10{sup −20} and 1.05×10{sup −20} cm{sup 2} for E//X, E//Y and E//Z, respectively. And the polarized absorption cross sections at 1538 nm is about 1.86×10{sup −20} cm{sup 2} for both E//X and E//Z, but for E//Y the result is 1.03×10{sup −20} cm{sup 2}, which is much smaller. The relationship between the crystal structure and absorption spectra was discussed. - Graphical abstract: The as-grown bulk Er:Yb:YCOB crystal (the long axis is along the b-axis) and LeBail fit to the XRPD pattern of Er:Yb:YCOB (top) compared to the diffraction pattern of YCOB from the JCPDS data bank (bottom). Reflection markers indicate the calculated reflection positions. The middle trace gives the difference between observed and calculated intensity. Reflection indices corresponding to the strongest diffraction peaks are marked on the experimental pattern. - Highlights: • Er:Yb:YCOB crystal with a new composition was grown. • XRPD and FT-IR showed a certain degree of deformation in the crystal structure. • Detailed polarized absorption cross sections at 977 nm and 1538 nm were calculated. • Crystal defects were clearly revealed by chemical etching experiments.

  12. Coupling of Ag Nanoparticle with Inverse Opal Photonic Crystals as a Novel Strategy for Upconversion Emission Enhancement of NaYF4: Yb(3+), Er(3+) Nanoparticles.

    PubMed

    Shao, Bo; Yang, Zhengwen; Wang, Yida; Li, Jun; Yang, Jianzhi; Qiu, Jianbei; Song, Zhiguo

    2015-11-18

    Rare-earth-ion-doped upconversion (UC) nanoparticles have generated considerable interest because of their potential application in solar cells, biological labeling, therapeutics, and imaging. However, the applications of UC nanoparticles were still limited because of their low emission efficiency. Photonic crystals and noble metal nanoparticles are applied extensively to enhance the UC emission of rare earth ions. In the present work, a novel substrate consisting of inverse opal photonic crystals and Ag nanoparticles was prepared by the template-assisted method, which was used to enhance the UC emission of NaYF4: Yb(3+), Er(3+) nanoparticles. The red or green UC emissions of NaYF4: Yb(3+), Er(3+) nanoparticles were selectively enhanced on the inverse opal substrates because of the Bragg reflection of the photonic band gap. Additionally, the UC emission enhancement of NaYF4: Yb(3+), Er(3+) nanoparticles induced by the coupling of metal nanoparticle plasmons and photonic crystal effects was realized on the Ag nanoparticles included in the inverse opal substrate. The present results demonstrated that coupling of Ag nanoparticle with inverse opal photonic crystals provides a useful strategy to enhance UC emission of rare-earth-ion-doped nanoparticles.

  13. Continuous-wave laser operation of Tm and Hoco-doped NaY(WO(4))(2) and NaLu(WO(4))(2) crystals.

    PubMed

    Han, X; Fusari, F; Serrano, M D; Lagatsky, A A; Cano-Torres, J M; Brown, C T A; Zaldo, C; Sibbett, W

    2010-03-15

    Tetragonal single crystals of NaT(WO(4))(2) (T = Y or Lu) co-doped with Tm(3+) and Ho(3+) ions have been employed for broadly tunable and efficient room-temperature laser operation at around 2 mum. With Ti:sapphire laser pumping at 795 nm, a slope efficiency and a maximum output power as high as 48% and 265 mW, respectively, have been achieved at 2050 nm from a Tm,Ho:NaY(WO(4))(2) crystal. Tuning from 1830 nm to 2080 nm has also been obtained using an intracavity Lyot filter.

  14. Half a century of progress in crystal growth of multifunctional borates RAl3(BO3)4 (R = Y, Pr, Sm-Lu)

    NASA Astrophysics Data System (ADS)

    Leonyuk, N. I.

    2017-10-01

    Investigations of multifunctional RAl3(BO3)4 (R = Y, Pr, Sm-Lu) crystals are divided into three stages: 1962-1972, 1972-1990, 1990 to present, and reviewed step by step. Selective and predominantly unpublished results on high-temperature flux growth (mostly by solution growth on dipped seeds, abbreviated as SGDS method) of these bulk (three-dimensional) crystals and their solid solutions, performed by the author's research group during last decades, are shortly summarized as well. The pursued studies can be considered as a key base for development of highly efficient optical and new laser systems.

  15. Nanostructured crystals of fluorite phases Sr{sub 1−x}R{sub x}F{sub 2+x} (R Are Rare Earth Elements) and their ordering: 10. Ordering under spontaneous crystallization and annealing of Sr{sub 1−x}R{sub x}F{sub 2+x} Alloys (R = Tb-Lu, Y) with 23.8–36.1 mol % RF{sub 3}

    SciTech Connect

    Sulyanova, E. A. Karimov, D. N.; Sulyanov, S. N.; Zhmurova, Z. I.; Golubev, A. M.; Sobolev, B. P.

    2015-01-15

    The products of spontaneous crystallization (at a cooling rate of ∼200 K/min) of Sr{sub 1−x}R{sub x}F{sub 2+x} melts in the homogeneity range of the fluorite phase have been investigated. Thirty-two irrational compositions with 23.8–36.1 mol % RF{sub 3} and eight rational Sr{sub 2}RF{sub 7} compositions are obtained. With respect to the RF{sub 3} content, these compositions form five groups: (1) Sr{sub 0.762}R{sub 0.238}F{sub 2.238} (23.8% RF{sub 3}), (2) Sr{sub 0.744}R{sub 0.256}F{sub 2.256} (25.6%), (3) Sr{sub 0.718}R{sub 0.282}F{sub 2.282} (28.2%), (4) Sr{sub 2}RF{sub 7} (33.3%), and (5) Sr{sub 0.639}R{sub 0.361}F{sub 2.361} (36.1%). R = Tb-Lu, Y for all groups. Quenching melts of group 5 with R = Tb, Dy, and Ho leads to the formation of ordered phases with the trigonal distortion of the rhβ-Na{sub 7}Zr{sub 6}F{sub 31} type, while for melts of group 5 with R = Lu, quenching yields a phase of the trigonal rhα′-Sr{sub 4}Lu{sub 3}F{sub 17} type. In group 5 with R = Y, Er, Tm, or Yb and in groups 1–4 with all REEs, fluorite phases are formed. Annealing at 900 ± 20°C for 96 h with subsequent cooling at a rate of ∼200 K/min expands the variety of ordered phases: a phase with a new r type of orthorhombic distortion is formed in group 1 with R = Lu, in group 2 with R = Tm or Lu, and in group 3 with R = Ho-Lu, Y; a t-Sr{sub 2}RF{sub 7} phase with tetragonal distortion is formed in group 4 with R = Tb-Er, Y; and a phase of trigonal rhα′ type is formed in group 5 with R = Y, Yb, or Lu. A fluorite phase arises in group 1 with R = Tb-Lu, Y as a result of quenching and annealing. The tendency to ordering becomes more pronounced with an increase in the RF{sub 3} content and REE atomic number. The annealing conditions do not provide equilibrium or the completely ordered state of all alloys.

  16. The development and performance of UV-enhanced APD-arrays for high resolution PET imaging coupled with pixelized Pr:LuAG crystal

    NASA Astrophysics Data System (ADS)

    Yoshino, M.; Kataoka, J.; Nakamori, T.; Matsuda, H.; Miura, T.; Katou, T.; Ishikawa, Y.; Kawabata, N.; Matsunaga, Y.; Kamada, K.; Usuki, Y.; Yoshikawa, A.; Yanagida, T.

    2011-07-01

    The development of high-resolution, UV-enhanced avalanche photodiode (APD) arrays usable in high-resolution PET imaging is underway. These APD arrays were specifically designed as photosensors capable of direct coupling with pixelized Pr-doped Lu 3Al 5O 12 (Pr:LuAG) scintillators. An excellent quantum efficiency (QE) of 55% was achieved at the peak emission of Pr:LuAG (310 nm), namely, a substantial improvement from the QE ≤5% as measured with the conventional Hamamatsu reverse-type APDs (S8664 series). Each APD device has 8×8 (TYP1) and 12×12 (TYP2) pixel structures with active areas of 3×3 mm 2 and 2×2 mm 2 in each pixel, respectively. A gain uniformity of ±8% and low dark noise of ≤2 nA/pixel have been achieved, measured at +25 °C. We also report on the large size single crystal growth of improved Pr:LuAG scintillators and the preliminary performance test of the same. An energy resolution of 4.2% (FWHM) was obtained for 662 keV gamma-rays for 10×10×10 mm 3 crystal, measured with a PMT employing a super-bialkali photocathode. We made a test module consisting of a UV-enhanced APD-array (either TYP1 or TYP2) optically coupled with an 8×8 (or 12×12) pixel Pr:LuAG matrix. The linearity between the output signals and incident gamma-ray energy of TYP1 and TYP2 gamma-ray detectors were only 0.27 and 0.33%, as measured at +25 °C for various gamma-ray sources, respectively. Energy resolutions of 7.0±0.2% (FWHM) and 9.0±0.6% (FWHM) were, respectively, obtained for TYP1 and TYP2 detector arrays for 662 keV gamma-rays. The uniformity of the pulse height distributions was also measured at less than 8% for both detectors. Finally, we measured the coincidence timing resolution of these gamma-ray detectors and obtained 4.0±0.1 ns (FWHM) for the 511 keV annihilation quanta from a 22Na source. These results suggest that UV-enhanced APD-arrays coupled with Pr:LuAG scintillators could be a promising device for future application in nuclear medicine.

  17. A new polymorph of Lu(PO(3))(3).

    PubMed

    Bejaoui, Anis; Horchani-Naifer, Karima; Férid, Mokhtar

    2008-07-19

    A new polymorph of lutetium polyphosphate, Lu(PO(3))(3), was found to be isotypic with the trigonal form of Yb(PO(3))(3). Two of the three Lu atoms occupy special positions (Wyckoff positions 3a and 3b, site symmetry ). The atomic arrangement consists of infinite helical polyphosphate chains running along the c axis, with a repeat period of 12 PO(4) tetra-hedra, joined with LuO(6) octa-hedra.

  18. Size/morphology induced tunable luminescence in upconversion crystals: ultra-strong single-band emission and underlying mechanisms

    NASA Astrophysics Data System (ADS)

    Wang, Zhaofeng; Zeng, Songshan; Yu, Jingfang; Ji, Xiaoming; Zeng, Huidan; Xin, Shuangyu; Wang, Yuhua; Sun, Luyi

    2015-05-01

    In this work, we present a two-step method to controllably synthesize novel and highly efficient upconversion materials, Lu5O4F7:Er3+,Yb3+ nano/micro-crystals, and investigate their size/morphology induced tunable upconversion properties. In addition to the common phenomenon aroused by a surface quenching effect, direct experimental evidence for the regulation of phonon modes is obtained in nanoparticles. The findings in this work advance the existing mechanisms for the general explanation of size/morphology induced upconversion features. Because of the adjustment of phonon energy and density as well as the surface quenching effect, the biocompatible Lu5O4F7:Er3+,Yb3+ nanoparticles exhibit an ultra-strong single-band red upconversion, rendering them promising for biomedical applications.In this work, we present a two-step method to controllably synthesize novel and highly efficient upconversion materials, Lu5O4F7:Er3+,Yb3+ nano/micro-crystals, and investigate their size/morphology induced tunable upconversion properties. In addition to the common phenomenon aroused by a surface quenching effect, direct experimental evidence for the regulation of phonon modes is obtained in nanoparticles. The findings in this work advance the existing mechanisms for the general explanation of size/morphology induced upconversion features. Because of the adjustment of phonon energy and density as well as the surface quenching effect, the biocompatible Lu5O4F7:Er3+,Yb3+ nanoparticles exhibit an ultra-strong single-band red upconversion, rendering them promising for biomedical applications. Electronic supplementary information (ESI) available: Crystal structure analysis, UV-Vis absorption spectra, SEM micrographs, surface micro-structure investigation, biocompatibility of Lu5O4F7: Er3+, Yb3+, as well as morphology and upconversion properties of the control sample NaYF4: Er3+, Yb3+. See DOI: 10.1039/c5nr01008j

  19. Synthesis, crystal structure, and magnetism of A{sub 2}Co{sub 12}As{sub 7} (A=Ca, Y, Ce–Yb)

    SciTech Connect

    Tan, Xiaoyan; Ovidiu Garlea, V.; Chai, Ping; Geondzhian, Andrey Y.; Yaroslavtsev, Alexander A.; Xin, Yan; Menushenkov, Alexey P.; Chernikov, Roman V.; Shatruk, Michael

    2016-04-15

    Ternary intermetallics, A{sub 2}Co{sub 12}As{sub 7} (A=Ca, Y, Ce–Yb), have been synthesized by annealing mixtures of elements in molten Bi at 1223 K. The materials obtained crystallize in the P6{sub 3}/m variant of the Zr{sub 2}Fe{sub 12}P{sub 7} structure type. The unit cell volume shows a monotonic decrease with the increasing atomic number of the rare-earth metal, with the exception of Ce-, Eu-, and Yb-containing compounds. An examination of these outliers with X-ray absorption near edge structures (XANES) spectroscopy revealed mixed valence of Ce, Eu, and Yb, with the average oxidation states of +3.20(1), +2.47(5), and +2.91(1), respectively, at room temperature. Magnetic behavior of A{sub 2}Co{sub 12}As{sub 7} is generally characterized by ferromagnetic ordering of Co 3d moments at 100–140 K, followed by low-temperature ordering of rare-earth 4f moments. The 3d-4f magnetic coupling changes from antiferromagnetic for A=Pr–Sm to ferromagnetic for A=Ce and Eu–Yb. Polarized neutron scattering experiments were performed to support the postulated ferro- and ferrimagnetic ground states for Ce{sub 2}Co{sub 12}As{sub 7} and Nd{sub 2}Co{sub 12}As{sub 7}, respectively. - Graphical abstract: Title arsenides were synthesized by Bi‐flux method. They exhibit mixed valence for A = Ce, Eu, Yb, ferrimagnetism for A = Ca, Y, Pr–Sm, and ferromagnetism for A = Eu–Tm. - Highlights: • A2Co12As7 (A=Ca, Y, Ce–Yb) were synthesized in Bi flux. • Ce, Eu, Yb exhibit mixed valence in the corresponding structures. • The character of 3d‐4f magnetic coupling changes at the half‐filled f shell. • Materials behave as ferrimagnets for A=Ca, Y, Pr–Sm and as ferromagnets for A=Eu–Yb.

  20. Nanostructured crystals of fluorite phases Sr1- x R x F2 + x and their ordering: 11. Influence of structural cluster ordering on fluorine ionic conductivity of the Sr1- x Lu x F2 + x Phase

    NASA Astrophysics Data System (ADS)

    Sorokin, N. I.; Sobolev, B. P.

    2015-11-01

    Ionic conductivity σ of the ordered phase (binary compound) Sr4Lu3F17 (sp. gr. Roverline 3 , Z = 6) with a fluorite-derivative structure obtained from a melt has been studied for the first time by impedance spectroscopy. The octahedral-cubic clusters {Sr8[Lu6F37]F32} formed in the structure of the disordered (fluorite) phase Sr1- x Lu x F2 + x (sp. gr. Fmoverline 3 m, Z = 4) become structural blocks with long-range order in the Sr4Lu3F17 compound. The effect of the clusters on the conductivity of nonstoichiometric phases Sr1- x Lu x F2 + x (2-25 mol % LuF3) and Sr4Lu3F17 (42.86 mol % LuF3) has been studied for the first time. Cluster ordering in Sr4Lu3F17 is accompanied by a decrease in the conductivity (σ = 6.3 × 10-7 S/cm at 673 K and Δ H σ = 1.12 eV) by a factor of 25 with respect to a disordered Sr0.75Lu0.25F2.75 crystal (experiment) and by a factor of 125 with respect to the saturated fluorite phase Sr0.63Lu0.37F2.37 (extrapolation). The unit-cell volume changes per F- ion during ordering are small and should not significantly affect the fluorine ion conductivity.

  1. Crystal field disorder effects in the optical spectra of Nd{sup 3+} and Yb{sup 3+}-doped calcium lithium niobium gallium garnets laser crystals and ceramics

    SciTech Connect

    Lupei, V.; Lupei, A.; Gheorghe, C.; Gheorghe, L.; Achim, A.; Ikesue, A.

    2012-09-15

    The optical spectroscopic properties of RE{sup 3+} (Nd, 1 at. % or Yb, 1 to 10 at. %)-doped calcium-lithium-niobium-gallium garnet (CLNGG) single crystals and ceramics in the 10 K-300 K range are analyzed. In these compositionally disordered materials, RE{sup 3+} substitute Ca{sup 2+} in dodecahedral sites and the charge compensation is accomplished by adjusting the proportion of Li{sup +}, Nb{sup 5+}, and Ga{sup 3+} to the doping concentration. The crystals and ceramics show similar optical spectra, with broad and structured (especially at low temperatures) bands whose shape depends on temperature and doping concentration. At 10 K, the Nd{sup 3+4}I{sub 9/2}{yields}{sup 4}F{sub 3/2,5/2} and Yb{sup 3+2}F{sub 7/2}{yields}{sup 2}F{sub 5/2} absorption bands, which show prospect for diode laser pumping, can be decomposed in several lines that can be attributed to centers with large differences in the crystal field. The positions of these components are the same, but the relative intensity depends on the doping concentration and two main centers dominate the spectra. Non-selective excitation evidences broad emission bands, of prospect for short-pulse laser emission, whereas the selective excitation reveals the particular emission spectra of the various centers. The modeling reveals that the nonequivalent centers correspond to RE{sup 3+} ions with different cationic combinations in the nearest octahedral and tetrahedral coordination spheres, and the most abundant two centers have 4Nb and, respectively, 3Nb1Li in the nearest octahedral sphere. At 300 K, the spectral resolution is lost. It is then inferred that the observed optical bands are envelopes of the spectra of various structural centers, whose resolution is determined by the relative contribution of the temperature-dependent homogeneous broadening and the effects of crystal field disordering (multicenter structure, inhomogeneous broadening). The relevance of spectroscopic properties for selection of pumping

  2. Cooperative down-conversion of UV light in disordered scheelitelike Yb-doped NaGd(MoO4)2 and NaLa(MoO4)2 crystals

    NASA Astrophysics Data System (ADS)

    Subbotin, K. A.; Osipova, Yu. N.; Lis, D. A.; Smirnov, V. A.; Zharikov, E. V.; Shcherbakov, I. A.

    2017-07-01

    Concentration series of disordered scheelitelike Yb:NaGd(MoO4)2 and Yb:NaLa(MoO4)2 single crystals are grown by the Czochralski method. The actual concentrations of Yb3+ ions in the crystals are determined by optical-absorption spectroscopy. The luminescence of Yb3+ ions in these crystals in the region of 1 μm is studied under UV and IR excitation. In the case of UV excitation, this luminescence appears as a result of nonradiative excited state energy transfer from donor centers of unknown nature to ytterbium. The character of the concentration dependence of Yb3+ luminescence indicates that the energy transfer at high Yb concentrations occurs with active participation of a cooperative mechanism, according to which the excitation energy of one donor center is transferred simultaneously to two Yb3+ ions. In other words, the quantum yield of this transfer exceeds unity, which can be used to increase the efficiency of crystalline silicon (c-Si) solar cells.

  3. Intermediate valence to heavy fermion through a quantum phase transition in Yb3(Rh1-xTx)4Ge13 (T = Co, Ir) single crystals

    NASA Astrophysics Data System (ADS)

    Rai, Binod; Morosan, Emilia

    Single crystals of Yb3(Rh1-x Tx)4Ge13 (T = Co, Ir) have been grown using the self-flux method. Powder X-ray diffraction data on these compounds are consistent with the cubic structure with space group Pm 3 n . Intermediate valence behavior is observed in Yb3(Rh1-x Tx)4Ge13 upon T = Co doping, while T = Ir doping drives the system into a heavy fermion state. Antiferromagnetic order is observed in the Ir-doped samples Yb3(Rh1-x Tx)4Ge13 for 0.5 < x <= 1 with TN = 0.96 K for Yb3Ir4Ge13. With decreasing x, the magnetic order is suppressed towards a quantum critical point around xc = 0.5, accompanied by non-Fermi liquid behavior evidenced by logarithmic divergence of the specific heat and linear temperature dependence of the resistivity. The Fermi liquid behavior is recovered with the application of large magnetic fields. Gordon and Betty Moore Foundation EPiQS initiative through Grant GBMF4417 and Welch Foundation.

  4. Preparation and photoluminescence properties of RE:Na{sub 3}La{sub 9}O{sub 3}(BO{sub 3}){sub 8} (RE=Er, Yb) crystals

    SciTech Connect

    Liu Zuoliang; Zhang, Guochun; Zhang Jianxiu; Bai Xiaoyan; Fu Peizhen; Wu Yicheng

    2010-06-15

    Using Na{sub 2}CO{sub 3}-H{sub 3}BO{sub 3}-NaF as fluxes, transparent RE:Na{sub 3}La{sub 9}O{sub 3}(BO{sub 3}){sub 8} (abbr. RE:NLBO, RE=Er, Yb) crystals have been grown by the top seed solution growth (TSSG) method. The X-ray powder diffraction analysis shows that the RE:NLBO crystals have the same structure with NLBO. The element contents were determined by molar to be 0.64% Er{sup 3+} in Er:NLBO, 2.70% Yb{sup 3+} in Yb:NLBO, respectively. The polarized absorption spectra of RE:NLBO have been measured at room temperature and show that both Er:NLBO and Yb:NLBO have a strong absorption bands near 980 nm with wide FWHM (Full Wave at Half Maximum) (21 nm for Er:NLBO and 25 nm for Yb:NLBO). Fluorescence spectra have been recorded. Yb:NLBO has the emission peaks at 985 nm, 1028 nm and 1079 nm and the emission peak of Er:NLBO is at 1536 nm. Spectral parameters have been calculated by the Judd-Ofelt theory for Er:NLBO and the reciprocity method for Yb:NLBO, respectively. The calculated values show that Er:NLBO is a candidate of 1.55 {mu}m laser crystals and Yb:NLBO is a candidate for self-frequency doubling crystal. - Graphical abstract: Fluorescence spectra show the emission peaks at 985, 1028 and 1079 nm of Yb:NLBO and at 1536 nm of Er:NLBO.

  5. Crystal growth, structure, and physical properties of Ln(Cu,Al)12 (Ln = Y, Ce, Pr, Sm, and Yb) and Ln(Cu, Ga)12 (Ln = Y, Gd-Er, and Yb).

    PubMed

    Drake, Brenton L; Capan, C; Cho, Jung Young; Nambu, Y; Kuga, K; Xiong, Y M; Karki, A B; Nakatsuji, S; Adams, P W; Young, D P; Chan, Julia Y

    2010-02-17

    Single crystals of Ln(Cu,Al)12 and Ln(Cu,Ga)12 compounds (Ln = Y, Ce-Nd, Sm, Gd-Ho, and Yb for Al and Ln = Y, Gd-Er, Yb for Ga) have been grown by flux-growth methods and characterized by means of single-crystal x-ray diffraction, complemented with microprobe analysis, magnetic susceptibility, resistivity and heat capacity measurements. Ln(Cu,Ga)12 and Ln(Cu,Al)12 of the ThMn12 structure type crystallize in the tetragonal I4/mmm space group with lattice parameters a approximately 8.59 Å and c approximately 5.15 Å and a approximately 8.75 Å and c approximately 5.13 Å for Ga and Al containing compounds, respectively. For aluminium containing compounds, magnetic susceptibility data show Curie-Weiss paramagnetism in the Ce and Pr analogues down to 50 K with no magnetic ordering down to 3 K, whereas the Yb analogue shows a temperature-independent Pauli paramagnetism. Sm(Cu,Al)12 orders antiferromagnetically at T(N)approximately 5 K and interestingly exhibits Curie-Weiss behaviour down to 10 K with no Van Vleck contribution to the susceptibility. Specific heat data show that Ce(Cu,Al)12 is a heavy fermion antiferromagnet with T(N) approximately 2 K and with an electronic specific heat coefficient γ0 as large as 390 mJ K2 mol(-1). In addition, this is the first report of Pr(Cu,Al)12 and Sm(Cu,Al)12 showing an enhanced mass (approximately 80 and 120 mJ K(2) mol(-1)). For Ga containing analogues, magnetic susceptibility data also show the expected Curie-Weiss behaviour from Gd to Er, with the Yb analogue being once again a Pauli paramagnet. The antiferromagnetic transition temperatures range over 12.5, 13.5, 6.7, and 3.4 K for Gd, Tb, Dy, and Er. Metallic behaviour is observed down to 3 K for all Ga and Al analogues. A large positive magnetoresistance up to 150% at 9 T is also observed for Dy(Cu,Ga)12. The structure, magnetic, and transport properties of these compounds will be discussed.

  6. Electronic structure of U3+ in Cs3Lu2Cl9 and Cs3Y2I9 single crystals.

    PubMed

    Karbowiak, Mirosław; Mech, Agnieszka; Drozdzyński, Janusz; Ryba-Romanowski, Witold; Reid, Michael F

    2005-01-13

    Low-temperature emission and polarized absorption spectra have been recorded for U(3+) ions diluted in Cs(3)Lu(2)Cl(9) and Cs(3)Y(2)I(9) host crystals. The experimental crystal-field levels were fitted to 13 parameters of a semiempirical Hamiltonian representing the combined atomic, one-electron crystal field (CF) as well as two-particle correlation crystal-field (CCF) operators. The red shift of the first f-d transitions from approximately 14,800 cm(-1) in the spectrum of U(3+):Cs(3)Lu(2)Cl(9) to as low as 11,790 cm(-1) in that of U(3+):Cs(3)Y(2)I(9) has been attributed to an increase in the covalence of the U(3+)-X(-) bonds. Comparison of the differences in the Coulomb repulsion strength between U(3+) and Er(3+) ions in Cs(3)Lu(2)Cl(9) and Cs(3)Y(2)I(9) crystals suggests that the 5f electrons of U(3+) ions are more 3d-like than 4f. The CF splitting of the (2)H(9/2) and (4)F(5/2) multiplets is unexpectedly larger for U(3+):Cs(3)Y(2)I(9) than for U(3+):Cs(3)Lu(2)Cl(9), which may be viewed as a result of the proximity of f-d states. For a correct description of the energy level structure of the (2)H(9/)(2) and (4)F(5/2) multiplets, the inclusion of CCF terms in the parametric Hamiltonian has proved to be essential. The larger f-f transition intensities for U(3+):Cs(3)Y(2)I(9) were also considered to be a consequence of the red shift of the first f-d states. The inadequacy in determination of the minor atomic parameters (other than parameters for Coulomb and spin-orbit interactions) and the insufficient inclusion of the influence of excited configuration in the applied CF Hamiltonian are assumed to be the main deficiencies preventing a better agreement between the experimental and calculated energies of CF levels.

  7. Thermal contact resistance measurement at the interface between Yb:YAG crystal and WCu cooler at 80 K and 300 K

    NASA Astrophysics Data System (ADS)

    Battaglia, J.-L.; Gavory, B.; Courjaud, A.

    2016-11-01

    The thermal resistance at the interface between a Yb:YAG crystal and WCu cooler has been measured at 80 K and 300 K using a hot disk technique. Furthermore, the technique allows retrieving the thermal conductivity for both materials at the two investigated temperature. Those results lead to envisage the implementation of the hot disk technique as an efficient non-destructive and in-situ technique to evaluate the quality of the interface between the crystal and the cooler during the assembling process as well as a during the use of the laser along its lifetime.

  8. Crystal fields, disorder, and antiferromagnetic short-range order in (Yb{sub 0.24}Sn{sub 0.76})Ru

    SciTech Connect

    Klimczuk, T; Wang, C H; Lawrence, J M; Xu, Q; Durakiewicz, T; Ronning, F; Llobet, A; Trouw, F; Kurita, N; Tokiwa, Y; Lee, Han-oh; Booth, C H; Gardner, J S; Bauer, E D; Joyce, J J; Zandbergen, H W; Movshovich, R; Cava, R J; Thompson, J D

    2011-07-18

    We report extensive measurements on a new compound (Yb{sub 0.24}Sn{sub 0.76})Ru that crystallizes in the cubic CsCl structure. Valence band photoemission and L{sub 3} x-ray absorption show no divalent component in the 4f configuration of Yb. Inelastic neutron scattering (INS) indicates that the eight-fold degenerate J-multiplet of Yb{sup 3+} is split by the crystalline electric field (CEF) into a Γ{sub 7} doublet ground state and a Γ{sub 8} quartet at an excitation energy 20 meV. The magnetic susceptibility can be fit very well by this CEF scheme under the assumption that a Γ{sub 6} excited state resides at 32 meV; however, the Γ{sub 8}/Γ{sub 6} transition expected at 12 meV was not observed in the INS. The resistivity follows a Bloch-Grüneisen law shunted by a parallel resistor, as is typical of systems subject to phonon scattering with no apparent magnetic scattering. All of these properties can be understood as representing simple local moment behavior of the trivalent Yb ion. At 1 K, there is a peak in specific heat that is too broad to represent a magnetic phase transition, consistent with absence of magnetic reflections in neutron diffraction. On the other hand, this peak also is too narrow to represent the Kondo effect in the Γ{sub 7} ground state doublet. On the basis of the field-dependence of the specific heat, we argue that antiferromagnetic shortrange order (possibly co-existing with Kondo physics) occurs at low temperatures. The long-range magnetic order is suppressed because the Yb site occupancy is below the percolation threshold for this disordered compound.

  9. Optical and scintillation characteristics of Gd2YAl2Ga3O12:Ce and Lu2YAl2Ga3O12:Ce single crystals

    NASA Astrophysics Data System (ADS)

    Chewpraditkul, Warut; Sakthong, Ongsa; Pattanaboonmee, Nakarin; Chewpraditkul, Weerapong; Szczesniak, Tomasz; Swiderski, Lukasz; Moszynski, Marek; Kamada, Kei; Yoshikawa, Akira; Nikl, Martin

    2017-06-01

    The optical and scintillation characteristics of Gd2YAl2Ga3O12:Ce and Lu2YAl2Ga3O12:Ce single crystals are investigated. At 662 keV γ-rays, light yield (LY) of 37,900 ph/MeV and energy resolution of 7.0% obtained for Gd2YAl2Ga3O12:Ce are superior to those of 18,900 ph/MeV and 11.5% obtained for Lu2YAl2Ga3O12:Ce. Scintillation decays are measured using the time-correlated single photon counting technique. A fast component decay time of 45 ns with relative intensity of 88% obtained for Lu2YAl2Ga3O12:Ce is superior to that of 50 ns (65%) for Gd2YAl2Ga3O12:Ce. The linear attenuation coefficient at 662 keV γ-rays is also determined and discussed.

  10. Population inversion of 1G4 excited state of Tm3+ investigated by means of numerical solutions of the rate equations system in Yb:Tm:Nd:LiYF4 crystal

    NASA Astrophysics Data System (ADS)

    Librantz, André Felipe Henriques; Gomes, Laércio; Courrol, Lilia Coronato; Ranieri, Izilda Marcia; Baldochi, Sonia Lícia

    2009-06-01

    In this work we present the spectroscopic properties of LiYF4 (YLF) single crystals activated with thulium and codoped with ytterbium and neodymium ions. The most important processes that lead to the thulium upconversion emissions in the blue region were identified. A time-resolved luminescence spectroscopy technique was employed to measure the luminescence decays and to determine the most important mechanisms involved in the upconversion process that populates G14(Tm3+) excited state. Analysis of the energy transfer processes dynamics using selective pulsed laser excitations in Yb:Tm:Nd, Tm:Nd, and Tm:Yb YLF crystals shows that the energy transfer from Nd3+ to Yb3+ ions is the mechanism responsible for the enhancement in the blue upconversion efficiency in the Yb:Tm:Nd:YLF when compared with the Yb:Tm system. A study of the energy transfer processes in YLF:Yb:Tm:Nd crystal showed that the G14 excited level is mainly populated by a sequence of two nonradiative energy transfers that start well after the Nd3+ and Tm3+ excitations at 797 nm according to Nd3+(F43/2)→Yb3+(F27/2), followed by Yb3+(F25/2)→Tm(H34)→Tm3+(G14) . Results of numerical simulation of the rate equations system showed that a population inversion for 481.4 nm laser emission line is attained for a pumping rate threshold of 26 s-1, which is equivalent to an intensity of 880 W cm-2 for a continuous laser pumping at 797 nm. On the other hand, a population inversion was not observed for the case of 960 nm (Yb3+) pumping.

  11. The influence of crystal structure on ion-irradiation tolerance in the Sm(x)Yb(2-x)TiO5 series

    SciTech Connect

    Aughterson, R. D.; Lumpkin, G. R.; de los Reyes, M.; Gault, B.; Baldo, P.; Ryan, E.; Whittle, K. R.; Smith, K. L.; Cairney, J. M.

    2016-04-01

    his ion-irradiation study covers the four major crystal structure types in the Ln(2)TiO(5) series (Ln = lanthanide), namely orthorhombic Pnma, hexagonal P63/mmc, cubic (pyrochlore-like) Fd-3m and cubic (fluorite-like) Fm-3m. This is the first systematic examination of the complete Ln(2)TiO(5) crystal system and the first reported examination of the hexagonal structure. A series of samples, based on the stoichiometry Sm(x)Yb(2-x)TiO5 (where x = 2, 1.4, 1, 0.6, and 0) have been irradiated using 1 MeV Kr2+ ions and characterised in-situ using a transmission electron microscope. Two quantities are used to define ion-irradiation tolerance: critical dose of amorphisation (D-c), which is the irradiating ion dose required for a crystalline to amorphous transition, and the critical temperature (T-c), above which the sample cannot be rendered amorphous by ion irradiation. The structure type plus elements of bonding are correlated to ion-irradiation tolerance. The cubic phases, Yb2TiO5 and Sm0.6Yb1.4TiO5, were found to be the most radiation tolerant, with Tc values of 479 and 697 K respectively. The improved radiation tolerance with a change in symmetry to cubic is consistent with previous studies of similar compounds.

  12. Optical characteristics of Er3+ ion in Er/Yb:LiNbO3 crystal: Comparison with the dissimilar effect of anti-photorefractive ions Zn2+, In3+ and Zr4+

    NASA Astrophysics Data System (ADS)

    Qian, Yannan; Wang, Rui; Wang, Biao; Xu, Chao; Xu, Wei; Xing, Lili; Xu, Yanling

    2013-11-01

    The different influences of Zn2+, In3+ and Zr4+ ions on the optical characteristics of Er3+ ion in Er/Yb:LiNbO3 crystals were discussed. An enhanced 1.54 μm emission was observed for Zr/Er/Yb:LiNbO3 crystal, but the Zn2+ tri-doping resulted in a decreased one, and the intensity of 1.54 μm emission remained about same in In/Er/Yb:LiNbO3 crystal. The populations of the green emitting 4S3/2/2H11/2 states were achieved through the three-, two- and two-phonon processes in Zn/Er/Yb:LiNbO3, In/Er/Yb:LiNbO3 and Zr/Er/Yb:LiNbO3 crystals, respectively. Zn2+ and In3+ ions affected the optical characteristics of Er3+ ion via modifying the Er3+ ion occupancy in Er/Yb:LiNbO3 crystal. The formation of ErLi2+-ErNb2- ion pairs caused by the Zn2+ and In3+ ions could increase the rate of cross relaxation process. The OH- absorption spectra showed that the incorporation of Zr4+ ions increased OH- content, which increased the probability of the nonradiative relaxation process of 4I11/2→4I13/2 (Er) in Zr/Er/Yb:LiNbO3 crystal. The J-O intensity parameters Ωt (t=2, 4 and 6), the radiative lifetime (τrad) and fluorescence branching ratio (β) in Zr/Er/Yb:LiNbO3 crystal were predicted by Judd-Ofelt theory. Füchtbauer-Ladenburg and McCumber methods were carried out to calculate the emission cross-sections at 1.54 μm emission. The gain cross-section, estimated as a function of the population inversion ratio, allowed us to evaluate a potential laser performance of Zr/Er/Yb:LiNbO3 crystal.

  13. Crystal growth of rare-earth orthovanadate (RVO 4) by the floating-zone method

    NASA Astrophysics Data System (ADS)

    Oka, Kunihiko; Unoki, Hiromi; Shibata, Hajime; Eisaki, Hiroshi

    2006-01-01

    Single crystals of rare-earth orthovanadate, RVO 4 where R=Y, La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb and Lu, with the cross-sectional size of about 7×7 mm 2 and 20-50 mm length have been successfully grown by the floating-zone method. Fluorescence properties at room temperature and dielectric and elastic properties along the c-axis of some grown crystals have been reported.

  14. Metal-to-metal charge transfer between dopant and host ions: Photoconductivity of Yb-doped CaF{sub 2} and SrF{sub 2} crystals

    SciTech Connect

    Barandiarán, Zoila Seijo, Luis

    2015-10-14

    Dopant-to-host electron transfer is calculated using ab initio wavefunction-based embedded cluster methods for Yb/Ca pairs in CaF{sub 2} and Yb/Sr pairs in SrF{sub 2} crystals to investigate the mechanism of photoconductivity. The results show that, in these crystals, dopant-to-host electron transfer is a two-photon process mediated by the 4f{sup N−1}5d excited states of Y b{sup 2+}: these are reached by the first photon excitation; then, they absorb the second photon, which provokes the Y b{sup 2+} + Ca{sup 2+} (Sr{sup 2+}) → Y b{sup 3+} + Ca{sup +} (Sr{sup +}) electron phototransfer. This mechanism applies to all the observed Y b{sup 2+} 4f–5d absorption bands with the exception of the first one: Electron transfer cannot occur at the first band wavelengths in CaF{sub 2}:Y b{sup 2+} because the Y b{sup 3+}–Ca{sup +} states are not reached by the two-photon absorption. In contrast, Yb-to-host electron transfer is possible in SrF{sub 2}:Y b{sup 2+} at the wavelengths of the first 4f–5d absorption band, but the mechanism is different from that described above: first, the two-photon excitation process occurs within the Y b{sup 2+} active center, then, non-radiative Yb-to-Sr electron transfer can occur. All of these features allow to interpret consistently available photoconductivity experiments in these materials, including the modulation of the photoconductivity by the absorption spectrum, the differences in photoconductivity thresholds observed in both hosts, and the peculiar photosensitivity observed in the SrF{sub 2} host, associated with the lowest 4f–5d band.

  15. Metal-to-metal charge transfer between dopant and host ions: Photoconductivity of Yb-doped CaF2 and SrF2 crystals

    NASA Astrophysics Data System (ADS)

    Barandiarán, Zoila; Seijo, Luis

    2015-10-01

    Dopant-to-host electron transfer is calculated using ab initio wavefunction-based embedded cluster methods for Yb/Ca pairs in CaF2 and Yb/Sr pairs in SrF2 crystals to investigate the mechanism of photoconductivity. The results show that, in these crystals, dopant-to-host electron transfer is a two-photon process mediated by the 4fN-15d excited states of Y b2+: these are reached by the first photon excitation; then, they absorb the second photon, which provokes the Y b2+ + Ca2+ (Sr2+) → Y b3+ + Ca+ (Sr+) electron phototransfer. This mechanism applies to all the observed Y b2+ 4f-5d absorption bands with the exception of the first one: Electron transfer cannot occur at the first band wavelengths in CaF2:Y b2+ because the Y b3+-Ca+ states are not reached by the two-photon absorption. In contrast, Yb-to-host electron transfer is possible in SrF2:Y b2+ at the wavelengths of the first 4f-5d absorption band, but the mechanism is different from that described above: first, the two-photon excitation process occurs within the Y b2+ active center, then, non-radiative Yb-to-Sr electron transfer can occur. All of these features allow to interpret consistently available photoconductivity experiments in these materials, including the modulation of the photoconductivity by the absorption spectrum, the differences in photoconductivity thresholds observed in both hosts, and the peculiar photosensitivity observed in the SrF2 host, associated with the lowest 4f-5d band.

  16. Metal-to-metal charge transfer between dopant and host ions: Photoconductivity of Yb-doped CaF2 and SrF2 crystals.

    PubMed

    Barandiarán, Zoila; Seijo, Luis

    2015-10-14

    Dopant-to-host electron transfer is calculated using ab initio wavefunction-based embedded cluster methods for Yb/Ca pairs in CaF2 and Yb/Sr pairs in SrF2 crystals to investigate the mechanism of photoconductivity. The results show that, in these crystals, dopant-to-host electron transfer is a two-photon process mediated by the 4f(N-1)5d excited states of Y b(2+): these are reached by the first photon excitation; then, they absorb the second photon, which provokes the Y b(2+) + Ca(2+) (Sr(2+)) → Y b(3+) + Ca(+) (Sr(+)) electron phototransfer. This mechanism applies to all the observed Y b(2+) 4f-5d absorption bands with the exception of the first one: Electron transfer cannot occur at the first band wavelengths in CaF2:Y b(2+) because the Y b(3+)-Ca(+) states are not reached by the two-photon absorption. In contrast, Yb-to-host electron transfer is possible in SrF2:Y b(2+) at the wavelengths of the first 4f-5d absorption band, but the mechanism is different from that described above: first, the two-photon excitation process occurs within the Y b(2+) active center, then, non-radiative Yb-to-Sr electron transfer can occur. All of these features allow to interpret consistently available photoconductivity experiments in these materials, including the modulation of the photoconductivity by the absorption spectrum, the differences in photoconductivity thresholds observed in both hosts, and the peculiar photosensitivity observed in the SrF2 host, associated with the lowest 4f-5d band.

  17. Polarized spectroscopic properties of Er3+:Gd2SiO5 crystal and evaluation of Er3+:Yb3+:Gd2SiO5 crystal as a 1.55 μm laser medium

    NASA Astrophysics Data System (ADS)

    Wang, H.; Huang, J. H.; Gong, X. H.; Chen, Y. J.; Lin, Y. F.; Luo, Z. D.; Huang, Y. D.

    2016-10-01

    An Er3+-doped Gd2SiO5 single crystal with high optical quality has been grown by the Czochralski method. Polarized absorption and fluorescence spectra and fluorescence lifetime of the crystal were measured at room temperature. Intensity parameters, spontaneous emission probabilities, fluorescence branching ratios, and radiative lifetimes were estimated on the basis of the Judd-Ofelt theory. Besides, potentiality of 1.55 μm laser emission in an Er3+-Yb3+ co-doped Gd2SiO5 crystal was evaluated.

  18. Physical optimization of production by deuteron irradiation of high specific activity (177g)Lu suitable for radioimmunotherapy.

    PubMed

    Manenti, Simone; Bonardi, Mauro L; Gini, Luigi; Groppi, Flavia

    2014-01-01

    Deuteron-induced nuclear reactions for generation of no-carrier-added (NCA) Lu isotopes were investigated using the stacked-foil activation technique on natural Yb targets at energies up to Ed=18.18MeV. The decay curve of ¹⁷⁷Yb, the growth curve of the cumulative (direct and indirect) and the direct production of (177g)Lu were determined. The analysis of these curves conducts to the evidence that the predominant route for the production of (177g)Lu is the indirect reaction ¹⁷⁶Yb(d,p)¹⁷⁷Yb, which decays to (177g)Lu. In the spectra acquired one year from the EOB the γ lines of (177m)Lu are not evident. A comparison between the calculated activity of (177g)Lu produced with a cyclotron and with a nuclear reactor is given. Copyright © 2014 Elsevier Inc. All rights reserved.

  19. Optical Spectra of Yb(3+) in Crystals with Scheelite Structure. I. Explanation of the Spectra.

    DTIC Science & Technology

    1980-09-01

    Czochralski method at this laboratory, 1 6 with the exception of the LiYF4 samples.* For the tungstates and the molybdates, the melt composition...without remounting the crystal. 16R. M. Curnutt, Czochralski Growth of Tungstate and Molybdate Scheelites, Harry Diamond Laboratories HDL-TM-70-8...1970), 4249. (16) R. M4. Curnutt, Czochralski Growth of Tungstate and Molybdate Scheelites, Harry Diamond Laboratories HDL-TM-70-8 (July 1970). (17

  20. Analysis of Sr{sub 5{minus}x}Ba{sub x}(PO{sub 4}){sub 3}F:Yb{sup 3+} crystals for improved laser performance with diode-pumping

    SciTech Connect

    Schaffers, K.I.; Bayramian, A.J.; Marshall, C.D.; Tassano, J.B.; Payne, S.A.

    1997-02-19

    Crystals of Yb{sup 3+}:Sr{sub 1-x}Ba{sub x}(PO{sub 4}){sub 3}F (0 < x < 5) have been investigated as a means to obtain broader absorption bands than are currently available with Yb{sup 3+}:S-FAP [Yb{sup 3+}: Sr{sub 5}(PO{sub 4}){sub 3}F], thereby improving diode-pumping efficiency for high peak power applications. Large diode-arrays have a FWHM pump band of >5 nm while the FWHM of the 900 nm absorption band for Yb:S-FAP is 5.5 nm; therefore, a significant amount of pump power can be wasted due to the nonideal overlap. Spectroscopic analysis of Yb:Sr{sub 5-x}Ba{sub x}-FAP crystals indicates that adding barium to the lattice increases the pump band to 13-16 run which more than compensates for the diode-array pump source without a detrimental reduction in absorption cross section. However, the emission cross section decreases by approximately half with relatively no effect on the emission lifetime. The small signal gain has also been measured and compared to the parent material Yb:S-FAP and emission cross sections have been determined by the method of reciprocity, the Filchtbauer-Ladenburg method, and small signal gain. Overall, Yb{sup 3+}:Sr{sub 5-x}Ba{sub x}(PO{sub 4}){sub 3}F crystals appear to achieve the goal of nearly matching the favorable thermal and laser performance properties of Yb:S-FAP while having a broader absorption band to better accommodate diode pumping.

  1. Effects of Mg-codoping on luminescence and scintillation properties of Ce doped Lu3(Ga,Al)5O12 single crystals

    NASA Astrophysics Data System (ADS)

    Yamaguchi, Hiroaki; Kamada, Kei; Pejchal, Jan; Kurosawa, Shunsuke; Shoji, Yasuhiro; Yokota, Yuui; Ohashi, Yuji; Yoshikawa, Akira

    2017-03-01

    Effects of Mg co-doping on scintillation properties of Ce:Lu3(Ga,Al)5O12 (LGAG) were investigated. Mg 200 ppm co-doped Ce:LGAG single crystals were prepared by micro pulling down method. Absorption and radioluminescence spectra were measured together with several other scintillation characteristics, namely the scintillation decay and light yield to reveal the effect of Mg co-doping. Ce4+ charge transfer absorption was observed below 340 nm in Mg,Ce:LGAG which is in good agreement with previous reports for other garnet-based crystals. The scintillation decay time showed the tendency to be accelerated and the light yield was enhanced by Mg co-doping.

  2. Crystal structures of orthorhombic, hexagonal, and cubic compounds of the Sm{sub (x)}Yb{sub (2−x)}TiO{sub 5} series

    SciTech Connect

    Aughterson, Robert D.; Lumpkin, Gregory R.; Reyes, Massey de los; Sharma, Neeraj; Ling, Christopher D.; Gault, Baptiste; Smith, Katherine L.; Avdeev, Maxim; Cairney, Julie M.

    2014-05-01

    A series of single phase compounds with nominal stoichiometry Sm{sub (x)}Yb{sub (2−x)}TiO{sub 5} (x=2, 1.4, 1, 0.6, and 0) have been successfully fabricated to generate a range of crystal structures covering the most common polymorphs previously discovered in the Ln{sub 2}TiO{sub 5} series (Ln=lanthanides and yttrium). Four of the five samples have not been previously fabricated in bulk, single phase form so their crystal structures are refined and detailed using powder synchrotron and single crystal x-ray diffraction, neutron diffraction and transmission electron microscopy. Based on the phase information from diffraction data, there are four crystal structure types in this series; orthorhombic Pnma, hexagonal P6{sub 3}/mmc, cubic (pyrochlore-like) Fd-3m and cubic (fluorite-like) Fm-3m. The cubic materials show modulated structures with variation between long and short range ordering and the variety of diffraction techniques were used to describe these complex crystal structure types. - Graphical abstract: A high resolution image of the compound Sm{sub 0.6}Yb{sub 1.4}TiO{sub 5} showing contrast from lattice fringes and the corresponding fast Fourier transform (FFT) of the HREM image with pyrochlore related diffraction spots marked “P” and fluorite marked “F”. The crystal is oriented down the [1 1 0] zone axis based on the Fd-3m structure. The ideal crystal structure (no vacancies) of the cubic, pyrochlore-like (Sm{sub 0.6}Yb{sub 1.4}TiO{sub 5}). - Highlights: • First fabrication of bulk single-phase material with stoichiometry Sm{sub 2}TiO{sub 5}. • Systematic study of crystal structure types within Ln{sub 2}TiO{sub 5} series (Ln=lanthanides). • A novel technique using IFFT of HREM images to study cubic structures.

  3. Rare-Earths Centers (Sm{sup 3+}, Eu{sup 3+}, Yb{sup 3+}) in MeF{sub 2}(Me = Ca, Sr, Ba, Cd) Crystals

    SciTech Connect

    Nikiforov, A. E.; Chernyshev, V. A.; Volodin, V. P.; Avram, N. M.; Avram, C. N.; Vaida, M.

    2010-08-04

    Rare-earth elements RE{sup 3+}(RE = Sm, Eu, Yb) form impurity centers in fluorite-like crystals MeF{sub 2}(Me = Ca, Sr, Ba, Cd). The crystal structure of cubic, trigonal and tetragonal centers in MeF{sub 2} has been investigated in the framework of shell model and pair potential approximation. The crystal field parameters were calculated with the exchange charges model, using the optimized geometry of the doped host matrix. With these parameters we have been calculated the optical spectra and spin-Hamiltonian (g-factors) of RE{sup 3+} in MeF{sub 2}, for some combination of R{sup 3+} and MeF{sup 2}. The obtained results were discussed and comparison with experimental data was made. A good agreement confirms the method and model of calculations.

  4. The potential of Yb:YCa4O(BO3)3 crystal in generating high-energy laser pulses.

    PubMed

    Liu, Junhai; Dai, Qibiao; Wan, Yong; Han, Wenjuan; Tian, Xueping

    2013-04-22

    The passive Q-switching laser performance of Yb:YCa(4)O(BO(3))(3) is studied with crystals cut along the principal optical axes. Using a Cr(4+):YAG saturable absorber with initial transmission of 93.7% and an output coupler of transmission of 40%, efficient Q-switched laser operation is achieved with a X-cut crystal, generating an output power of 2.14 W at a pulse repetition rate of 4.5 kHz. The resulting laser pulse is 9.3 ns in duration, with the energy being as high as 476 μJ and the peak power amounting to 51.2 kW. The results demonstrated in this work reveal the great potential of this crystal in developing high-energy compact pulsed lasers.

  5. Comparative studies for Cr4+:YAG crystal and AlGaInAs semiconductor used as a saturable absorber in Q-switched Yb-doped fiber lasers.

    PubMed

    Huang, J Y; Zhuang, W Z; Huang, W C; Su, K W; Hu, C; Huang, K F; Chen, Y F

    2009-11-09

    We demonstrate comparative studies for Cr(4+):YAG crystal and AlGaInAs quantum-well (QW) used as a saturable absorbers in passively Q-switched Yb-doped fiber lasers. Both saturable absorbers were designed to be possessed of nearly the same initial transmission. Under a pump power of 24 W, the average output powers were up to 14.4 W and 13.8 W obtained with the AlGaInAs QWs and with the Cr(4+):YAG crystal, respectively. The maximum pulse energies obtained with the Cr(4+):YAG crystal and with the AlGaInAs QWs were found to be 0.35 mJ and 0.45 mJ, respectively.

  6. Synthesis, crystal structure, and magnetism of A2Co12As7 (A=Ca, Y, Ce–Yb)

    SciTech Connect

    Tan, Xiaoyan; Ovidiu Garlea, V.; Chai, Ping; Geondzhian, Andrey Y.; Yaroslavtsev, Alexander A.; Xin, Yan; Menushenkov, Alexey P.; Chernikov, Roman V.; Shatruk, Michael

    2015-08-28

    In this study, ternary intermetallics, A2Co12As7 (A=Ca, Y, Ce–Yb), have been synthesized by annealing mixtures of elements in molten Bi at 1223 K. The materials obtained crystallize in the P63/m variant of the Zr2Fe12P7 structure type. The unit cell volume shows a monotonic decrease with the increasing atomic number of the rare-earth metal, with the exception of Ce-, Eu-, and Yb-containing compounds. An examination of these outliers with X-ray absorption near edge structures (XANES) spectroscopy revealed mixed valence of Ce, Eu, and Yb, with the average oxidation states of +3.20(1), +2.47(5), and +2.91(1), respectively, at room temperature. Magnetic behavior of A2Co12As7 is generally characterized by ferromagnetic ordering of Co 3d moments at 100–140 K, followed by low-temperature ordering of rare-earth 4f moments. The 3d-4f magnetic coupling changes from antiferromagnetic for A=Pr–Sm to ferromagnetic for A=Ce and Eu–Yb. Finally, polarized neutron scattering experiments were performed to support the postulated ferro- and ferrimagnetic ground states for Ce2Co12As7 and Nd2Co12As7, respectively.

  7. Highly Efficient LiYF4:Yb(3+), Er(3+) Upconversion Single Crystal under Solar Cell Spectrum Excitation and Photovoltaic Application.

    PubMed

    Chen, Xu; Xu, Wen; Song, Hongwei; Chen, Cong; Xia, Haiping; Zhu, Yongsheng; Zhou, Donglei; Cui, Shaobo; Dai, Qilin; Zhang, Jiazhong

    2016-04-13

    Luminescent upconversion is a promising way to harvest near-infrared (NIR) sunlight and transforms it into visible light that can be directly absorbed by active materials of solar cells and improve their power conversion efficiency (PCE). However, it is still a great challenge to effectively improve the PCE of solar cells with the assistance of upconversion. In this work, we demonstrate the application of the transparent LiYF4:Yb(3+), Er(3+) single crystal as an independent luminescent upconverter to improve the PCE of perovskite solar cells. The LiYF4:Yb(3+), Er(3+) single crystal is prepared by an improved Bridgman method, and its internal quantum efficiency approached to 5.72% under 6.2 W cm(-2) 980 nm excitation. The power-dependent upconversion luminescence indicated that under the excitation of simulated sunlight the (4)F(9/2)-(4)I(15/2) red emission originally results from the cooperation of a 1540 nm photon and a 980 nm photon. Furthermore, when the single crystal is placed in front of the perovskite solar cells, the PCE is enhanced by 7.9% under the irradiation of simulated sunlight by 7-8 solar constants. This work implies the upconverter not only can serve as proof of principle for improving PCE of solar cells but also is helpful to practical application.

  8. Growth and spectral properties of a promising laser crystal Yb3+/Er3+:Ca9La(VO4)7

    NASA Astrophysics Data System (ADS)

    Li, Ming; Sun, Shijia; Zhang, Lizhen; Yuan, Feifei; Huang, Yisheng; Lin, Zhoubin

    2016-10-01

    A new crystal of Er3+/Yb3+:Ca9La(VO4)7 was grown successfully by the Czochralski method. Its spectral properties were investigated in detail. The crystal has a strong absorption band near 980 nm with a full-width at half-maximum of 33 nm, which means that it is very suitable for InGaAs laser diode pumping. Based on the Judd-Ofelt theory, the intensity parameters and radiative lifetime were obtained. The fluorescence lifetime of the 4I13/2 level of the Er3+ ion is 4.28 ms. The emission cross sections of the Er3+ ion at 1533 nm calculated by the Füchtbauer-Ladenburg method are 0.86 × 10-20 cm2 and 1.08 × 10-20 cm2 for σ- and π- polarization, respectively. The results indicate that Er3+/Yb3+:Ca9La(VO4)7 crystal is a potential 1.5-1.6 μm laser material.

  9. Crystallization kinetics and spectroscopic investigations on Tb{sup 3+} and Yb{sup 3+} codoped glass ceramics containing CaF{sub 2} nanocrystals

    SciTech Connect

    Huang Lihui; Qin Guanshi; Arai, Yusuke; Jose, Rajan; Suzuki, Takenobu; Ohishi, Yasutake; Yamashita, Tatsuya; Akimoto, Yusuke

    2007-11-01

    Transparent Tb{sup 3+} and Yb{sup 3+} codoped oxyfluoride glass ceramics containing CaF{sub 2} nanocrystals were prepared by melt quenching and subsequent heat treatment. Crystallization kinetics of CaF{sub 2} nanocrystals was investigated by differential scanning calorimetric method. The average apparent activation energy E{sub a} of the crystallization was {approx}498 kJ/mol. Moreover, the value of the Avrami exponent n was 1.01. These results suggest that the crystallization mechanism of CaF{sub 2} is a diffusion controlled growth process of needles and plates of finite long dimensions. X-ray diffraction patterns and transmission electron microscopy image confirmed the CaF{sub 2} nanocrystals in the glass ceramic. Ultraviolet (UV) and visible emission spectra of the as-made glass and the glass ceramic with an excitation of a 974 nm laser diode were recorded at room temperature. An intense UV emission at 381 nm was observed in the glass ceramic. The origin of the enhancement of the emission at 381 nm was investigated using spectroscopic technique and Judd-Ofelt analysis. The enhancement of the emission at 381 nm could be attributed to the change of the ligand field of Tb{sup 3+} ions due to the incorporation of some Tb{sup 3+} and Yb{sup 3+} ions into CaF{sub 2} nanocrystals in the glass ceramic.

  10. Structural and spectral studies of Yb:NaGd(WO4)2 crystals irradiated by 6.0 MeV O ions

    NASA Astrophysics Data System (ADS)

    Jia, Chuan-Lei; Li, Song; Song, Xiao-Xiao

    2017-03-01

    Yb:NaGd(WO4)2 single crystals are implanted with 6.0 MeV O ions at room temperature. The effects of ion irradiation on the structure and spectral properties are demonstrated by employing X-ray diffraction techniques, high resolution X-ray diffraction techniques and photoluminescence (PL) measurement. The corresponding results show that the sample can retain good crystallinity by irradiation at relative low fluences of 1.6 × 1014 ions/cm2, whilst both the PL intensity and the line bandwidth can be effectively improved.

  11. Energy transfer rates and population inversion investigation of 1G4 and 1D2 excited states of Tm3+ in Yb:Tm:Nd:KY3F10 crystals

    NASA Astrophysics Data System (ADS)

    Marconi da Silva, Horácio; Linhares, M. D.; Henriques Librantz, André Philipe; Gomes, Laércio; Coronato Courrol, Lilia; Baldochi, Sonia Lícia; Ranieri, Izilda Marcia

    2011-04-01

    In this work we present the spectroscopic properties of KY3F10 (KY3F) single crystals activated with thulium and co-doped with ytterbium and neodymium ions. The most important processes that lead to the thulium up-conversion emissions in the blue and ultraviolet regions were identified. A time-resolved luminescence spectroscopy technique was employed to measure the luminescence decays and to determine the most important mechanisms involved in the up-conversion process that populates 1G4 and 1D2 (Tm3+) excited states. Analysis of the energy-transfer processes dynamics using selective pulsed-laser excitations in Yb:Tm:Nd, Tm:Nd, and Tm:Yb KY3F crystals show that the energy transfer from Nd3+ to Yb3+ ions is the mechanism responsible for the enhancement of the blue up-conversion efficiency in the Yb:Tm:Nd:KY3F when compared with the Yb:Tm system. A study of the energy transfer processes in Yb:Tm:Nd:KY3F crystal showed that the 1G4 excited level is mainly populated by a sequence of two nonradiative energy transfers that starts well after the Nd3+ and Tm3+ excitation at 797 nm according to: Nd3+ (4F3/2) → Yb3+ (2F7/2) followed by Yb3+ (2F5/2) → Tm (3H4) → Tm3+ (1G4). Results of numerical simulation of the rate equations system showed that a population inversion for 483.1 nm laser emission line is attained for a pumping rate threshold of 98 s-1, which is equivalent to an intensity of 3.3 KW cm-2 for a continuous laser pumping at 797 nm for Yb(30 mol%):Tm(0.5 mol%):Nd(1 mol%):KY3F. Nevertheless, best Yb3+ concentration for the laser emission near 483.1 nm was estimated to be within 40 and 50 mol%. On the other hand, a population inversion was not observed for the case of 960 nm (Yb3+) pumping.

  12. Comparative study of eye-safe Nd:LuAG crystal and ceramic lasers at 1.83 μm operating on 4F3/2 → 4I15/2 transition

    NASA Astrophysics Data System (ADS)

    Zhou, Zhiyong; Wang, Yi; Xu, Bin; Xu, Huiying; Cai, Zhiping; Xu, Xiaodong; Li, Dongzhen; Xu, Jun

    2017-08-01

    We report on diode-pumped Nd:LuAG crystal and ceramic lasers operating at about 1.83 μm, using a simple and compact plane-concave cavity configuration. For Nd:LuAG crystal laser oscillating at 1828.43 nm, the maximum output power reaches 0.36 W with slope efficiency of about 5.0%. For Nd:LuAG ceramic laser, a maximum output power of 0.145 W is achieved with slope efficiency of about 2.2%, and the lasing wavelength peaks at 1828.76 nm. The 1.83-μm Nd laser sources could be very promising for eye-safe applications because they have stronger water absorption than another kind of eye-safe Nd lasers operating at 1.4 μm.

  13. Yb:S-FAP Lasers

    SciTech Connect

    Schaffers, K I

    2004-01-20

    It has recently been reported that several high power, diode-pumped laser systems have been developed based on crystals of Yb:S-FAP [Yb{sup 3+}:Sr{sub 5}(PO{sub 4}){sub 3}F]. The Mercury Laser, at Lawrence Livermore National Laboratory, is the most prominent system using Yb:S-FAP and is currently producing 23J at 5 Hz in a 15 nsec pulse, based on partial activation of the system. In addition, a regenerative amplifier is being developed at Waseda University in Japan and has produced greater than 12 mJ with high beam quality at 50Hz repetition rate. Q-peak has demonstrated 16 mJ of maximum energy/output pulse in a multi-pass, diode side-pumped amplifier and ELSA in France is implementing Yb:S-FAP in a 985 nm pump for an EDFA, producing 250 mW. Growth of high optical quality crystals of Yb:S-FAP is a challenge due to multiple crystalline defects. However, at this time, a growth process has been developed to produce high quality 3.5 cm diameter Yb:S-FAP crystals and a process is under development for producing 6.5 cm diameter crystals.

  14. Electron-paramagnetic-resonance investigations of /sup 243/Cm/sup 3 +/ and /sup 244/Cm/sup 3 +/ in LuPO/sub 4/ single crystals

    SciTech Connect

    Abraham, M.M.; Boatner, L.A.

    1982-08-01

    The actinide isotopes /sup 243/Cm and /sup 244/Cm have been incorporated as dilute trivalent impurities in single crystals of lutetium orthophosphate. Electron-paramagnetic-resonance (EPR) spectra of both isotopes were observed at approx.9 GHz and T = 4.2 K, and a positive identification of the Cm/sup 3 +/ resonance was made from the six-line hyperfine pattern characteristic of the I = 5/2 nuclear spin of /sup 243/Cm. The host LuPO/sub 4/ crystal is a tetragonal-symmetry system and the axial Cm/sup 3 +/ g values were determined to be g/sub parallel/ = 7.98(1) and g/sub perpendicular/ = 4.096(4). These values could not be fit to a doublet wave function of the form ..cap alpha..Vertical Bar +- 7/2>+..beta..Vertical Barminus-or-plus1/2> to give a consistent value for the Lande g factor. They could, however, be fit to an excited-state doublet wave function of the form ..cap alpha..Vertical Bar +- 5/2>+..beta..Vertical Barminus-or-plus3/2> to yield a consistent Lande factor of 1.921. The identification of the observed spectra as arising from an excited state was confirmed by the observation that lowering the temperature reduced the intensity of the EPR signals. These results show that the sign of the dominant axial crystal-field term for the 5f/sup 7/ Cm/sup 3 +/ ion in LuPO/sub 4/ is negative and that a predominantly Vertical Bar +- 7/2> state is the ground state.

  15. Chloride derivatives of lanthanoid(III) ortho-oxidotungstates(VI) with the formula LnCl[WO4] (Ln=Gd-Lu): Syntheses, crystal structures and spectroscopic properties

    NASA Astrophysics Data System (ADS)

    Schustereit, Tanja; Schleid, Thomas; Höppe, Henning A.; Kazmierczak, Karolina; Hartenbach, Ingo

    2015-03-01

    The lanthanoid(III) chloride ortho-oxidotungstates(VI) with the formula LnCl[WO4] crystallize monoclinically in space group C2/m (a=1019-1032, b=721-733, c=682-689 pm and β=107-108°, Z=4) for Ln=Gd-Er and triclinically in space group P1¯ (a=593-596, b=719-721, c=684-686 pm, α=93-94, β≈103 and γ≈122°, Z=2) for Ln=Tm-Lu. The monoclinic structure contains crystallographically unique Ln3+ cations, which are surrounded by two Cl- and six O2- anions forming distorted trigonal dodecahedra. Their fusion via common edges leads to anionic layers ∞ 2 {[ LnCl2/2eO4/2eO2/1t ] 6 - }. The polyhedra around the Ln3+ cations in the triclinic crystal structure are also built up by two Cl-, but only five O2- anions to form distorted monocapped trigonal prisms. Their linkage through edges constitutes anionic strands ∞ 1 {[ LnCl2/2eO2/2eO3/1t ] 6 - } along [100]. The complex anionic entities of both LnCl[WO4] arrangements become interconnected by W6+ cations to complete the structures by generating discrete [WO4]2- tetrahedra. Since the title compounds emerge as pure phases according to X-ray powder diffractometry, spectroscopic measurements such as single crystal Raman as well as diffuse reflectance spectroscopy (DRS) were performed. Furthermore, GdCl[WO4] and LuCl[WO4] are suitable host materials for doping with Eu3+, which leads to materials with a red luminescence upon excitation with UV light for both structures. Moreover, TbCl[WO4] exhibits a Tb3+-typical yellow-green bulk luminescence upon UV excitation, which could be analyzed by luminescence spectroscopy.

  16. 10J water-cooled DPSSL system based on Yb:YAG crystal edge-cladded by Cr:YAG ceramics (Conference Presentation)

    NASA Astrophysics Data System (ADS)

    Zheng, Jian-Gang; Yan, Xiongwei; Jiang, Xinying; Wang, Zhenguo; Li, Mingzhong; Zhang, Jun; Zhu, Qihua; Zheng, Wanguo

    2017-05-01

    Laser Inertial Fusion Energy (IFE) has been attracting the interests of the researchers around the world, because of the promising to the future energy. The Yb:YAG was broadly used in the research field of high-peak power and large energy laser with repetition-rate for IFE because of its outstanding performance, including significant thermal and mechanical capacities, long upper energy level lifetime, high quantum efficiency and highly doping capacity. But it exhibits high saturation fluence at room temperature because of the small emission and absorption cross-section. And at the same time this gain material exhibits self-absorption of laser because of the thermal population at lower laser level at room temperature. Ant it appears to have been solved by means of the cryogenic temperature, but the total efficiency of the laser system will be decreased as the use of cryogenic temperature. The amplified spontaneous emission (ASE) effect of the amplifier can be relaxed by means of edge-cladded absorption material. And the difficulties of edge cladding can be will solved as the emergence of ceramics. But at present the ceramics exhibits high scattering and many disfigurements, which limited the application in the high-power large-energy laser system. So the edge-cladding of Yb:YAG crystal will be a key issue for solution the ASE in amplifier. In this paper, we will introduce a 10J water-cooled DPSSL system, based on Yb:YAG crystal at room temperature. In this system a new edge cladding method has been used, that the Yb:YAG crystal was edge cladded by Cr:YAG ceramics, which was used as the absorption material of ASE. The amplifier was an active mirror water-cooled room temperature amplifier. With the help of this edge cladding the ASE has been lowered, and about 5 times small signal gain has been obtained in a single pass amplification, which was much higher than the earlier of 2 times. And the wavefront aberrance of the laser beam was also reduced due to the thermal

  17. Transport and Magnetic Properties of Single-Crystal Lu(Ni_1- xCo_x)_2B_2C (x = 0 - 0.09)

    NASA Astrophysics Data System (ADS)

    Cheon, K. O.; Fisher, I. R.; Kogan, V.; Canfield, P. C.

    1998-03-01

    In fields greater than approximately 1 kG (H_crit), the vortex lattice of LuNi_2B_2C has a four-fold (square) symmetry. Weaker applied fields result in a triangular vortex lattice. Theoretical models of this phase transition involve both the coherence length and the mean free path. Small amounts of cobalt substitution allow for the careful adjustment of both quantities, and provides a practical method for increasing H_crit. Results of resistivity and dc-magnetic susceptibility measurements are presented for single-crystal samples of Lu(Ni_1-xCo_x)_2B_2C (x = 0 - 0.09). Residual resistivities (ρ_0) are a factor of five smaller than values obtained for polycrystalline samples. We find that (ρ_0) increases by 1.5 μΩcm per percent Co. Implications of these results for values of the hex-to-square vortex lattice transition will be discussed. Ames Laboratory is operated for the U.S. Department of Energy by Iowa State University under Contract No. W-7405-Eng-82.

  18. The crystal structure and luminescence of Ce3+, Tb3+ and Eu3+ in KBaLn3+(BO3)2 [Ln3+ = Sc, Y, Lu, Gd

    NASA Astrophysics Data System (ADS)

    Camardello, S. J.; Her, J. H.; Toscano, P. J.; Srivastava, A. M.

    2015-11-01

    The structure of KBaLn3+(BO3)2 [Ln3+ = Sc, Lu, Gd] was solved by Rietveld refinement of the powder X-ray diffraction data. The materials crystallize with the mineral Buetschliite [K2Ca(CO3)2] structure. The lattice parameters of KBaLn3+(BO3)2 [Ln3+ = Sc, Lu, Gd] increased with increasing ionic radius of the Ln3+ cation. In this structure, the Ln3+ cations are octahedrally coordinated. The phase formation region is dependent on the ionic radii of the Ln3+ cation. The optical properties of Ce3+, Tb3+ and Eu3+ and their dependence on the host lattice composition are investigated and discussed. It is noteworthy that the optical properties of these ions are independent of the Ln3+ cation in KBaLn3+(BO3)2. It is concluded that in this family of materials, the crystalline field strength and the covalence at the rare earth site is independent of the host lattice composition.

  19. Investigation of the magnetic properties in double perovskite R2CoMnO6 single crystals (R  =  rare earth: La to Lu).

    PubMed

    Kim, M K; Moon, J Y; Choi, H Y; Oh, S H; Lee, N; Choi, Y J

    2015-10-28

    We have successfully synthesized the series of the double-perovskite R2CoMnO6 (R  =  rare earth: La to Lu) single crystals and have investigated their magnetic properties. The ferromagnetic order of Co(2+)/Mn(4+) spins emerges mainly along the c axis. Upon decreasing the size of rare earth ion, the magnetic transition temperature decreases linearly from 204 K for La2CoMnO6 to 48 K for Lu2CoMnO6, along with the enhancement of monoclinic distortion. The temperature and magnetic-field dependences of magnetization reveal the various magnetic characteristics such as the metamagnetic transition in R  =  Eu, the isotropic nature of rare earth moment in R  =  Gd, and the reversal of magnetic anisotropy in R  =  Tb and Dy. Our results offer comprehensive information for understanding the roles of mixed-valent magnetic ions and rare earth magnetic moments on the magnetic properties.

  20. Optical and magneto-optical properties of single crystals of RFe{sub 2} (R = Gd, Tb, Ho, and Lu) and GdCo{sub 2} intermetallic compounds

    SciTech Connect

    Lee, S.J.

    1999-02-12

    The author has studied the diagonal and off-diagonal optical conductivity of RFe{sub 2}(R = Gd, Tb, Ho, Lu) and GdCo{sub 2} single crystals grown by the flux method. Using spectroscopic ellipsometry the author has measured the dielectric function from 1.5 to 5.5 eV. The magneto-optical Kerr spectrometer at temperatures between 7 and 295 K and applied magnetic fields between 0.5 to 1.6 T. The apparatus and calibration method are described in detail. Using magneto-optical data and optical constants he derives the experimental value of the off-diagonal conductivity components. Theoretical calculations of optical conductivities and magneto-optical parameters were performed using the tight binding-linear muffin tin orbitals method within the local spin density approximation. He applied this TB-LMTO method to LuFe{sub 2}. The theoretical results obtained agree well with the experimental data. The oxidation effects on the diagonal part of the optical conductivity were considered using a three-phase model. The oxidation effects on the magneto-optical parameters were also considered by treating the oxide layer as a nonmagnetic thin transparent layer. These corrections change not only the magnitude but also the shape of the optical conductivity and the magneto-optical parameters.

  1. Effect of Yb doping on the refractive index and thermo-optic coefficient of YVO4 single crystals.

    PubMed

    Soharab, M; Bhaumik, Indranil; Bhatt, R; Saxena, A; Karnal, A K; Gupta, P K

    2017-02-20

    Single crystals of YVO4 with different doping concentrations of Yb (1.5, 3.0, 8.0, and 15.0 at. %) and with good crystalline quality (FWHM ∼43-55 arc sec of rocking curve) were grown by the optical floating zone technique. Refractive index measurements were carried out at four wavelengths as a function of temperature. The measurements show that as the doping concentration of Yb is increased, the refractive index varies marginally for ne whereas there is a significant change in the value of no. The thermo-optic coefficient (dn/dT) was found to be positive with a value ∼10-5/°C, which is 1 order higher than that for the undoped YVO4 crystal. The thermo-optic coefficient is higher for ne compared to that of no. Also, a set of relations describing the wavelength dependence of the thermo-optic coefficient were established that are useful for calculating the thermo-optic coefficient at any temperature in the range 30°C-150°C and at any wavelength in the range 532-1551 nm.

  2. Crystal growth and physical properties of europium-based quaternary Chevrel phases (RE 1- xEu xMo 6S 8; RE-Sm, Yb)

    NASA Astrophysics Data System (ADS)

    Schmitt, H.; Pen˜a, O.; Perrin, A.; Padiou, J.; Sergent, M.; Torikachvili, M.; Beille, J.

    1992-02-01

    Rare-earth-based Chevrel phases constitute model systems to study both superconductivity and magnetic order but results may be hindered by the quality of the sample. Materials elaboration is thus essential to separate out extrinsic effects (secondary phases) from those due to the Mo 6S 8 clusters and the rare-earth contribution. Crystal growth, transport and magnetic properties of the quaternary systems (RE, Eu)Mo 6S 8 (RE-Sm, Yb) are presented. Different RE/Eu nominal ratios allowed to cover a large range of concentrations for single crystals. Superconducting transitions are narrow and as high as 9 K for ytterbium-rich samples, while the structural transition of the ternary EuMo 6S 8 ( T s = 110 K) is largely diminished by the partial substitution of Eu by RE.

  3. Anisotropic upper critical field of single crystal RNi[sub 2]B[sub 2]C (R = Y, Lu)

    SciTech Connect

    Du Mar, A.C.; Rathnayaka, K.D.D.; Naugle, D.G. . Dept. of Physics); Canfield, P.C. . Dept. of Physics and Astronomy Ames Lab., IA )

    1998-12-20

    Measurements of the anisotropic upper critical field curves have been extended for YNi[sub 2]B[sub 2]C and LuNi[sub 2]B[sub 2]C ([Tc] = 15.6 K and 16.1 K, respectively). Measurements of R(T, H) were taken along the crystallographic directions of (100) and (110). The resulting critical fields show an upward curvature near [Tc] and a linear behavior at low temperature, which continues to below 2 K with little, if any, sign of saturation.

  4. Spectroscopic properties and high-power laser operation of Yb0.14:Y0.77Gd0.09Ca4O(BO3)3 mixed crystal

    NASA Astrophysics Data System (ADS)

    Chen, Xiaowen; Xu, Honghao; Han, Wenjuan; Wang, Lisha; Liu, Junhai; Yu, Haohai; Zhang, Huaijin

    2016-05-01

    We report, for the first time to our knowledge, on the spectroscopic properties and continuous-wave laser performance of Yb0.14:Y0.77Gd0.09Ca4O(BO3)3, a mixed rare earth calcium oxyborate Yb-ion crystal. Under simple end-pumping conditions with a 976-nm diode, efficient CW laser operation was demonstrated at room temperature, producing an output power of 14.1 W at 1084.4 nm with an optical-to-optical efficiency of 48%; while operating around 1045 nm, the laser could generate an output power as high as 23.0 W, with optical-to-optical and slope efficiencies amounting, respectively, to 57% and 70% with respect to incident pump power. The polarized absorption and emission cross sections are also presented. The impressive results demonstrated reveal the great potential of these mixed oxyborates in developing new promising Yb-ion laser crystals.

  5. Crystal Structure of Superconducting 1/1 Cubic Au-Ge-Yb Approximant with Tsai-Type Cluster

    NASA Astrophysics Data System (ADS)

    Deguchi, Kazuhiko; Nakayama, Mika; Matsukawa, Shuya; Imura, Keiichiro; Tanaka, Katsumasa; Ishimasa, Tsutomu; Sato, Noriaki K.

    2015-01-01

    We report the synthesis of a single-phase sample of the superconducting crystalline approximant Au64.0Ge22.0Yb14.0 and present a structure model refined by Rietveld analysis for X-ray diffraction data.

  6. Crystal structures of RPt{sub 3-x}Si{sub 1-y}(R=Y, Tb, Dy, Ho, Er, Tm, Yb) studied by single crystal X-ray diffraction

    SciTech Connect

    Gribanov, Alexander; Grytsiv, Andriy; Rogl, Peter; Seropegin, Yurii; Giester, Gerald

    2009-07-15

    The crystal structures of ternary compounds RPt{sub 3-x}Si{sub 1-y}(R=Y, Tb, Dy, Ho, Er, Tm, Yb) have been elucidated from X-ray single crystal CCD data. All compounds are isotypic and crystallize in the tetragonal space group P4/mbm. The general formula RPt{sub 3-x}Si{sub 1-y} arises from defects: x{approx}0.20, y{approx}0.14. The crystal structure of RPt{sub 3-x}Si{sub 1-y} can be considered as a packing of four types of building blocks which derive from the CePt{sub 3}B-type unit cell by various degrees of distortion and Pt, Si-defects. - Graphical Abstract: Electron density in RPt{sub 3-x}Si{sub 1-y} at 0, 1/2 , 0.

  7. Syntheses and crystal structures of RE{sub 3}MnSn{sub 5-x} (RE=Tm, Lu) with 3D Mn-Sn framework

    SciTech Connect

    Lei Xiaowu; Hu Chunli; Mao Jianggao

    2010-09-15

    Four new isostructural rare earth manganese stannides, namely RE{sub 3}MnSn{sub 5-x} (x=0.16(6), 0.29(1) for RE=Tm, x=0.05(8), 0.21(3) for RE=Lu), have been obtained by reacting the mixture of corresponding pure elements at high temperature. Single-crystal X-ray diffraction studies revealed that they crystallized in the orthorhombic space group Pnma (No. 62) with cell parameters of a=18.384(9)-18.495(6) A, b=6.003(3)-6.062(2) A, c=14.898(8)-14.976(4) A, V=1644.3(14)-1679.0(9) A{sup 3} and Z=8. Their structures belong to the Hf{sub 3}Cr{sub 2}Si{sub 4} type and feature a 3D framework composed of 1D [Mn{sub 2}Sn{sub 7}] chains interconnected by [Sn{sub 3}] double chains via Sn-Sn bonds, forming 1D large channels based on [Mn{sub 4}Sn{sub 16}] 20-membered rings along the b-axis, which are occupied by the rare earth atoms. Electronic structure calculations based on density functional theory (DFT) for idealized 'RE{sub 3}MnSn{sub 5}' model indicate that these compounds are metallic, which are in accordance with the results from temperature-dependent resistivity measurements. - Graphical abstract: The new isostructural rare earth manganese stannides, namely RE{sub 3}MnSn{sub 5-x} (RE=Tm, Lu), have been synthesized by reacting the mixture of the corresponding pure elements and structurally characterized.

  8. Vortex operation in Er:LuYAG crystal laser at ∼1.6 μm

    NASA Astrophysics Data System (ADS)

    Liu, Qiyao; Zhao, Yongguang; Zhou, Wei; Shen, Deyuan

    2017-09-01

    An Er3+-doped Lu1.5Y1.5Al5O12 (Er:LuYAG) solid-state laser with direct generation of optical vortex is reported. The vortex laser operation was realized through being pumped by an annular beam at 1532 nm, which was reformatted by a specially fabricated optical mirror. With two different laser output couplers of 10% and 20% transmissions, pure LG01 mode lasers with right-handedness at 1647.7 nm and 1619.5 nm were yielded from a simple two-mirror cavity, respectively, without any helicity control optical element. Furthermore, stable pulse trains at 1647.7 nm have been achieved via employing an acousto-optic Q-switch, and ∼0.66 mJ pulsed energy and ∼65 ns pulse duration were finally obtained at 1 kHz repetition rate, corresponding to a peak power of ∼10.2 kW. The generated pulse vortex maintained LG01 mode with well-determined right-handedness, as in the case of cw laser operation.

  9. Crystal growth of pyrochlore rare-earth stannates

    NASA Astrophysics Data System (ADS)

    Prabhakaran, D.; Wang, S.; Boothroyd, A. T.

    2017-06-01

    We report crystal growth of several rare-earth stannates RE2Sn2O7 (RE=Pr, Tb, Ho, Dy, Yb and Lu) using the flux technique. Different combinations of flux were tried, and a Na2B4O7-NaF (1.2:1) mixture was found to be suitable for crystal growth. X-ray diffraction and thermal characterisation data are presented, as well as some initial measurements of magnetic and thermodynamic properties of the crystals. Little effect was observed with changing oxygen content by Sc substitution for Sn.

  10. Defects Identification and Effects of Annealing on Lu2(1-x)Y2xSiO5 (LYSO) Single Crystals for Scintillation Application

    PubMed Central

    Blahuta, Samuel; Bessière, Aurélie; Viana, Bruno; Ouspenski, Vladimir; Mattmann, Eric; Lejay, Julien; Gourier, Didier

    2011-01-01

    The nature, properties and relative concentrations of electronic defects were investigated by Thermoluminescence (TL) in Lu2(1-x)Y2xSiO5 (LYSO) single crystals. Ce and Tb-doped single crystals, grown by the Czochralski technique (CZ), revealed similar traps in TL. LYSO:Ce single crystals were grown by the Floating-Zone technique (FZ) with increasing oxygen concentration in the growth atmosphere. TL intensity is strongly dependent on the oxygen content of the material, and oxygen vacancies are proven to be the main electronic defects in LYSO. The effects of oxidizing and reducing annealing post-treatment on these defects were investigated. While oxidizing treatments efficiently reduce the amount of electronic defects, reducing treatments increase the amount of existing traps. In a thermally assisted tunneling mechanism, the localization of oxygen vacancies around the dopant is discussed. They are shown to be in the close vicinity of the dopant, though not in first neighbor positions. PMID:28824138

  11. Excitation function for deuteron induced nuclear reactions on natural ytterbium for production of high specific activity 177g Lu in no-carrier-added form for metabolic radiotherapy.

    PubMed

    Manenti, Simone; Groppi, Flavia; Gandini, Andrea; Gini, Luigi; Abbas, Kamel; Holzwarth, Uwe; Simonelli, Federica; Bonardi, Mauro

    2011-01-01

    Deuteron-induced nuclear reactions for generation of no-carrier-added Lu radionuclides were investigated using the stacked-foil activation technique on natural Yb targets at energies up to E(d)=18.18 MeV. Excitation functions of the reactions (nat)Yb(d,xn)(169,170,171,172,173,174g,174m,176m,177g)Lu and (nat)Yb(d,pxn)(169,175,177)Yb have been measured, among them three ((169)Lu, (174m)Lu and (176m)Lu) are reported for the first time. The upper limit of the contamination from the long-lived metastable level (177m)Lu was evaluated too. Thick-target yields for all investigated radionuclides are calculated.

  12. Hydrogen in polar intermetallics: Syntheses and structures of the ternary Ca5Bi3D0.93, Yb5Bi3Hx, and Sm5Bi3H~1 by powder neutron or single crystal X-ray diffraction

    SciTech Connect

    Leon-Escamilla, E. Alejandro; Dervenagas, Panagiotis; Stasis, Constantine; Corbett, John D.

    2010-01-01

    The syntheses of the title compounds are described in detail. Structural characterizations from refinements of single crystal X-ray diffraction data for Yb{sub 5}Bi{sub 3}H{sub x} and Sm{sub 5}Bi{sub 3}H{sub 1} and of powder neutron diffraction data for Ca{sub 5}Bi{sub 3}D{sub 0.93(3)} are reported. These confirm that all three crystallize with the heavy atom structure type of {beta}-Yb{sub 5}Sb{sub 3}, and the third gives the first proof that the deuterium lies in the center of nominal calcium tetrahedra, isostructural with the Ca{sub 5}Sb{sub 3}F-type structure. These Ca and Yb phases are particularly stable with respect to dissociation to Mn{sub 5}Si{sub 3}-type product plus H{sub 2}. Some contradictions in the literature regarding Yb{sub 5}Sb{sub 3} and Yb{sub 5}Sb{sub 3}H{sub x} phases are considered in terms of adventitious hydrogen impurities that are generated during reactions in fused silica containers at elevated temperatures.

  13. XPS Studies of Yb14MnSb11 and Yb14ZnSb11

    SciTech Connect

    Holm, A P; Ozawa, T C; Kauzlarich, S M; Morton, S A; Waddill, G D; Pickett, W E; Tobin, J G

    2003-10-02

    Measurements of core and valence electronic states of single crystals of the rare earth transition metal Zintl phases Yb{sub 14}MnSb{sub 11} and Yb{sub 14}ZnSb{sub 11} were performed using the X-ray photoelectron spectroscopy station of Beamline 7 at the Advanced Light Source. Sample surfaces of Yb{sub 14}MnSb{sub 11} and Yb{sub 14}ZnSb{sub 11} were measured as received, after Ar{sup +} ion bombardment, and after cleaving in situ. Detailed analysis of the clean Mn and Zn analog sample surfaces reveal a significant contribution of both Yb{sup 3+} and Yb{sup 2+} 4f states in the valence band region for the Zn analog and no contribution of Yb{sup 3+} states to the valence band for the Mn analog. This result is predicted for the Zn analog by Zintl counting rules, and single crystal X-ray diffraction studies presented here also support the mixed valency of Yb for Yb{sub 14}ZnSb{sub 11}. Further detailed analysis of the core and valence band structure of both Yb{sub 14}MnSb{sub 11} and Yb{sub 14}ZnSb{sub 11} will be presented.

  14. Crystallographic and dielectric properties of flux grown PbB1/2'B1/2″O (B'B″: InNb, InTa, YbNb, YbTa and MgW) single crystals

    NASA Astrophysics Data System (ADS)

    Kania, Antoni

    2008-05-01

    Single crystals of PbIn 1/2Nb 1/2O 3 (PIN), PbIn 1/2Ta 1/2O 3 (PIT), PbYb 1/2Nb 1/2O 3 (PYN), PbYb 1/2Ta 1/2O 3 (PYT) and PbMg 1/2W 1/2O 3 (PMW) have been grown by the flux method. The PbO-based solvents were used. Transparent, light yellow and arrow like shaped PIN and PIT crystals of the perovskite structure were obtained. Small amounts of red and of octahedron habit PIN and PIT crystals of the pyrochlore type were simultaneously grown. In the case of PYN, PYT and PMW only the crystals of the perovskite structure have been grown. The transparent and brown PYN and PYT crystals of octahedron habit were obtained. The transparent, light yellow and of octahedron or truncated octahedron shape PMW crystals were grown. The crystals were characterised by X-ray and dielectric studies. They showed that as-grown PIN crystals are nearly disordered, exhibit the rhombohedral distortion of the pseudo-perovskite unit cell and reveal relaxor behaviour. The partially ordered PIT crystals show monoclinic distortion and undergo antiferroelectric-paraelectric phase transition. The PYN, PYT and PMW single crystals, characterised by chemical order in the B'/B″ ion sublattice, exhibit orthorhombic symmetry and undergo the first-order antiferroelectric-paraelectric phase transitions.

  15. Diode-pumped 88-fs Kerr-lens mode-locked Yb:Y₃Ga₅O₁₂ crystal laser.

    PubMed

    Zhang, Jinwei; Han, Hainian; Tian, Wenlong; Lv, Liang; Wang, Qing; Wei, Zhiyi

    2013-12-02

    We realized a stable Kerr-lens mode-locked operation in a diode-pumped Yb:Y₃Ga₅O₁₂ laser. Pulses as short as 88 fs at the center wavelength of 1042 nm were obtained at a repetition rate of 159.3 MHz. The maximum output power was 104 mW under the incident pump power of 3.9 W. By comparing the mode-locked characteristics under different output transmissions, we obtained pulses with the highest output power of 330 mW and a duration of 149 fs. To the best of our knowledge, this is the first demonstration of a Kerr-lens mode-locked Yb:Y₃Ga₅O₁₂ laser.

  16. Generation of visible wavelength by the phase-matching four-wave mixing in an Yb-doped V-shape photonic crystal fiber

    NASA Astrophysics Data System (ADS)

    Li, Lixiao; Yuan, Jinhui; Sang, Xinzhu; Yan, Binbin; Wang, Kuiru; Yu, Chongxiu; Han, Ying; Xia, Changming; Zhou, Guiyao; Wei, Shuai; Wang, Chao; Yang, Jianju; Wang, Shuang; Cheng, Xu; Hou, Lantian

    2015-07-01

    In this paper, an Ytterbium-doped V-shape photonic crystal fiber (Yb-VPCF) with low dispersion and high nonlinearity is designed and fabricated in our laboratory. Through coupling femtosecond pulses into the fundamental mode of Yb-VPCF, the tunable anti-Stokes signals at the visible wavelength are efficiently generated based on the phase-matching four-wave mixing. When the pump wavelength is changed from 810, to 820, and to 830 nm and the input average power is increased from 0.4, to 0.5, and to 0.6 W, respectively, the anti-Stokes signals are generated within the wavelength range of 562-477 nm. The wavelength-tunable range is over 100 nm, and the maximum power ratio of anti-Stokes signal at 477 nm and the residual pump at 830 nm can be up to 23.9:1. The anti-Stokes signals generated can be used as the ultrashort pulse sources for ultrafast optoelectronics and spectroscopy.

  17. Investigations of YAG:Er(3+),Yb(3+) and YAG:Co(2+) Crystals for Laser Applications

    DTIC Science & Technology

    2001-01-01

    doped YAG crystals are given. Erbium and ytterbium doped YAG single crystals were obtained by the Czochralski method . The spectral properties and laser...relaxation time of 290 Rts14 2. CRYSTAL GROWTH The crystals were obtained by the Czochralski method , using iridium crucibles of external dimensions...YAG:Co 2+ single crystal grown by Czochralski method is presented. In all obtained crystals the core area of the characteristic threefold symmetry was

  18. High-power and high-efficiency diode-pumped Nd:LuYAG mixed crystal lasers operating at 939 and 946  nm.

    PubMed

    Cui, Qin; Lan, Jinglong; Lin, Zhi; Xu, Bin; Xu, Huiying; Cai, Zhiping; Xu, Xiaodong; Zhang, Jian; Xu, Jun

    2016-09-10

    We report on high-performance infrared lasers at 0.94 μm based on quasi-three-level transition of F3/24→I9/24 in Nd:LuYAG mixed crystal, for the first time to our knowledge. The maximum output power was achieved to 5.64 W with slope efficiency of approximately 52.5% at 946 nm. The simultaneous dual-wavelength laser at 939 and 946 nm is also obtained with maximum output power of 3.61 W and slope efficiency of 34.8% by introducing a glass etalon into the cavity. Moreover, a 2.0-W single-wavelength laser at 939 nm can be further attained by suitably tilting the etalon. Using a Cr:YAG saturable absorber, Q-switched laser operation is realized with maximum average output power of 0.68 W and the narrowest pulse width of 8.4 ns, which results in the maximum single pulse energy of approximately 55.3 μJ and the maximum pulse peak power of approximately 6.15 kW. Finally, thermal focal length of the laser crystal is estimated by using a flat-flat laser cavity.

  19. A new polymorph of Lu(PO3)3

    PubMed Central

    Bejaoui, Anis; Horchani-Naifer, Karima; Férid, Mokhtar

    2008-01-01

    A new polymorph of lutetium polyphosphate, Lu(PO3)3, was found to be isotypic with the trigonal form of Yb(PO3)3. Two of the three Lu atoms occupy special positions (Wyckoff positions 3a and 3b, site symmetry ). The atomic arrangement consists of infinite helical polyphosphate chains running along the c axis, with a repeat period of 12 PO4 tetra­hedra, joined with LuO6 octa­hedra. PMID:21202991

  20. Chemical preparation, crystal structure and characterization of the new sodium ytterbium cyclotriphosphate Na{sub 3}Yb(P{sub 3}O{sub 9}){sub 2}.9H{sub 2}O

    SciTech Connect

    Chehimi-Moumen, F. . E-mail: fathia.chehimi@fsb.rnu.tn; Ferid, M.

    2007-01-18

    Chemical preparation and crystal structure are reported for a new lanthanide cyclotriphosphate Na{sub 3}Yb(P{sub 3}O{sub 9}){sub 2}.9H{sub 2}O. This salt crystallizes in the trigonal system, space group R3-bar c with the following parameters: a=30.933(2), c=12.8282(5)A. The crystal structure was refined to R{sub 1}=0.0432 using 1782 reflections with I>2 {sigma}(I). In the Na{sub 3}Yb(P{sub 3}O{sub 9}){sub 2}.9H{sub 2}O structure, the phosphoric ring anions, located around the 3-bar axis are interconnected by YbO{sub 8} dodecahedra and NaO{sub 6} and NaO{sub 7} polyhedra to build, around the threefold axis, large channels parallel to the c axis. All the nine water molecules in the present arrangement participate in the coordination spheres of the associated cations. The thermogravimetric analysis shows that the removal of these water molecules occurs in three stages between 305 and 736K. The vibrational study by IR absorption spectroscopy of Na{sub 3}Yb(P{sub 3}O{sub 9}){sub 2}.9H{sub 2}O is also reported.

  1. Influence of the d-electron concentration on the itinerant electron metamagnetism and ferromagnetism in M(Co 1- xAl x) 2 systems (M = Y, Lu): study of compounds with unvariable crystal cell parameter

    NASA Astrophysics Data System (ADS)

    Gabelko, I. L.; Levitin, R. Z.; Markosyan, A. S.; Silant'ev, V. I.; Snegirev, V. V.

    1991-03-01

    Magnetic properties of the (Y 1- tLu t)(Co 1- xAl x) 2 system in which the crystal cell parameter was kept constant by partial substitution of lutetium for yttrium have been investigated in dependence of the aluminum concentration within the 0 ⩽ x ⩽ 0.22 interval. The concentration dependence of the critical field of the metamagnetic transition and the character of arising of ferromagnetic order are analyzed. The magnetic ( x- T) phase diagram of (Y 1- tLu t)(Co 1- xAl x) 2 system is obtained. The comparison with analogous results for Y(Co 1- xAl x) 2 and Lu(Co 1- xAl x) 2 systems, in which the itinerant electron metamagnetism have been observed earlier, leads to the conclusion that the main factor acting on the transformation of magnetic properties of YCo 2 and LuCo 2 when aluminum replaces cobalt is the change of d-electron concentration but not the increase of the crystal cell parameter.

  2. Enhanced upconversion emission in crystallization-controllable glass-ceramic fiber containing Yb(3+)-Er(3+) codoped CaF2 nanocrystals.

    PubMed

    Peng, Wencai; Fang, Zaijin; Ma, Zhijun; Qiu, Jianrong

    2016-10-07

    Functional nanocrystal-containing materials have been a hot topic in recent years. However, few researches have focused on functional nanocrystals contained in optical glass fibers. In this research, transparent CaF2 glass-ceramic was prepared by a melt-quenching method. Greatly enhanced upconversion luminescence was observed after heat treatment. By applying a novel method called melt-in-tube, precursor fiber free of crystals was fabricated at the drawing temperature where the clad was softened while the core was melted. Glass-ceramic fiber with fiber core containing Yb(3+)-Er(3+) codoped CaF2 nanocrystals was obtained after heat treatment at a relatively low temperature. Electron probe micro-analyzer measurement shows no obvious element diffusion between the core and clad. Greatly enhanced upconversion emission was detected in the glass-ceramic fiber excited by a 980 nm laser, suggesting the developed glass-ceramic fiber is a promising material for upconversion laser.

  3. High-power passively Q-switched Yb:YCa4O(BO3)3 laser with a GaAs crystal plate as saturable absorber.

    PubMed

    Chen, Xiaowen; Han, Wenjuan; Xu, Honghao; Jia, Minghui; Yu, Haohai; Zhang, Huaijin; Liu, Junhai

    2015-04-10

    We report on efficient high-power passively Q-switched operation of a Yb:YCa4O(BO3)3 laser with a GaAs crystal plate acting as the saturable absorber. An average output power of 5.7 W at 1032 nm is generated at a pulse repetition rate of 166.7 kHz when the incident pump power is 26.8 W, with a slope efficiency determined to be 24.5%. The averaged pulse energy achieved is roughly 30 μJ and is increased to about 40 μJ when the output coupling used changes from 30% to 50%, while the shortest pulse width is measured to be 153 ns.

  4. Enhanced upconversion emission in crystallization-controllable glass-ceramic fiber containing Yb3+-Er3+ codoped CaF2 nanocrystals

    NASA Astrophysics Data System (ADS)

    Peng, Wencai; Fang, Zaijin; Ma, Zhijun; Qiu, Jianrong

    2016-10-01

    Functional nanocrystal-containing materials have been a hot topic in recent years. However, few researches have focused on functional nanocrystals contained in optical glass fibers. In this research, transparent CaF2 glass-ceramic was prepared by a melt-quenching method. Greatly enhanced upconversion luminescence was observed after heat treatment. By applying a novel method called melt-in-tube, precursor fiber free of crystals was fabricated at the drawing temperature where the clad was softened while the core was melted. Glass-ceramic fiber with fiber core containing Yb3+-Er3+ codoped CaF2 nanocrystals was obtained after heat treatment at a relatively low temperature. Electron probe micro-analyzer measurement shows no obvious element diffusion between the core and clad. Greatly enhanced upconversion emission was detected in the glass-ceramic fiber excited by a 980 nm laser, suggesting the developed glass-ceramic fiber is a promising material for upconversion laser.

  5. A monomeric solvent-free bent lanthanide dialkyl and a lanthanide analogue of a Grignard reagent. Crystal structures of Yb[l brace]C(SiMe[sub 3])[sub 3][r brace][sub 2] and [Yb[l brace]C(SiMe[sub 3])[sub 3][r brace]I[center dot]OEt[sub 2

    SciTech Connect

    Eaborn, C.; Hitchcock, P.B.; Izod, K.; Smith, J.D. )

    1994-12-28

    There is much current interest in the organometallic chemistry of the f-block elements. Considerable progress has been made in developing the chemistry of the +3[sub la] and 0[sub lb] oxidation states: work on the +2 oxidation state has been mainly concerned with polyhapto ligands, especially substituted cyclopentadienyls. We report the synthesis and crystal structure of bis[l brace]tris-(trimethylsilyl)methyl[r brace] ytterbium, Yb[l brace]C(SiMe[sub 3])[sub 3][r brace][sub 2], obtained in good yield as a highly air- and moisture-sensitive orange solid from the reaction between YbI[sub 2] and K[l brace]C(SiMe[sub 3])[sub 3][r brace][sup 5] in benzene, and the determination of its crystal structure. As far as we are aware this is the first solvent-free dialkyl lanthanide to be characterized. We also describe the preparation and structure of an Yb analogue of a Grignard reagent; these have been used in synthesis but have not previously been isolated. The most interesting and surprising feature of the solid-state structure is that the C-Yb-C angle is 137[degree]. 19 refs., 2 figs.

  6. Single crystal growth and heat capacity measurements of triangular lattice R2Pt6Ga15 (R =rare earth)

    NASA Astrophysics Data System (ADS)

    Matsumoto, Y.; Ueda, T.; Ohara, S.

    2016-02-01

    We have succeeded in synthesizing the single crystal of R2Pt6Ga15 (R=La-Nd, Sm- Lu) with hexagonal Sc0.67Fe2Si5-type structure using Ga self flux method. The crystal structure was confirmed by the powder X-ray method. The unit-cell volume V of R2Pt6Ga15 follows the lanthanide concentration except R = Ce, Eu and Yb, indicating that the valences of R = La, Pr, Nd, Sm, Gd-Tm, and Lu ion are trivalent, whereas those of R = Ce, Eu and Yb ion are deviate from trivalent. We have measured the specific heat C(T) of R2Pt6Ga15. It is found that the magnetic order takes place in R2Pt6Ga15 (R=Pr, Nd, Sm-Tm). Moreover, the multiple phase transitions were observed in R2Pt6Ga15 (R = Nd, Eu, Gd and Ho).

  7. Effects of disorder and isotopic substitution in the specific heat and Raman scattering in LuB{sub 12}

    SciTech Connect

    Sluchanko, N. E. Azarevich, A. N.; Bogach, A. V.; Vlasov, I. I.; Glushkov, V. V.; Demishev, S. V.; Maksimov, A. A.; Tartakovskii, I. I.; Filatov, E. V.; Flachbart, K.; Gabani, S.; Filippov, V. B.; Shitsevalova, N. Yu.; Moshchalkov, V. V.

    2011-09-15

    Precision measurements of the specific heat and spectral intensity I({omega}) of Raman scattering for Lu{sup N}B{sub 12} single crystal samples with various boron isotopes (N = 10, 11, nat) have been performed at low and intermediate temperatures. A boson peak in the low-frequency part of the I({omega}) spectrum has been observed for the first time for lutetium dodecaboride at liquid nitrogen temperatures. It has been shown that low-temperature anomalies in the specific heat, along with the features of Raman spectra, can be interpreted in terms of the transition to a cageglass state at T* = 50-70 K, which appears when Lu{sup 3+} ions are displaced from the centrosymmetric position in cavities of a rigid covalent boron sublattice towards the randomly located boron vacancies. The concentrations of various two-level systems that correspond to two types of vibrational clusters with correlation lengths of 12-15 and 18-22 A, respectively, have been estimated. The vibrational density of states of LuB{sub 12} has been calculated from Raman spectra in the model of soft atomic potentials. An approach has been proposed to explain the dielectrization of the properties of the YbB{sub 12} compound at T < T*, as well as the features of the formation of magnetic structures in RB{sub 12} antiferromagnets (R = Tb, Dy, Ho, Er, Tm) and the suppression of superconductivity in LuB{sub 12}.

  8. Influence of air annealing temperature and time on the optical properties of Yb:YAG single crystal grown by HDS method

    NASA Astrophysics Data System (ADS)

    Nie, Ying; Liu, Yang; Zhao, Yequan; Zhang, Mingfu

    2015-08-01

    8 at.% Yb:YAG plate single crystal with the dimension of 170 mm × 150 mm × 30 mm was grown in vacuum by Horizontal Directional Solidification method. Aimed at blue-green color centers, annealing treatments of 15 mm × 15 mm × 1 mm samples from 900 °C to 1400 °C for 5 h and at 900 °C from 5 h to 40 h in air were conducted. The absorption spectra, emission spectra, fluorescence lifetime and X-ray photoelectron spectroscopy of samples under different annealing conditions were measured at room temperature, respectively. Annealing at above 1000 °C for 5 h or at 900 °C for 40 h made the blue-green color centers disappear and the samples turned to transparent. Absorption coefficients decreased in the 300 nm-800 nm wavelength range, emission intensities increased and emission bands broadened around 486 nm and 1029 nm with increasing temperature up to 1200 °C, then varied inversely. These values decreased or increased monotonically with increasing annealing time at 900 °C. The maximal increases of fluorescence lifetime were 62.3% and 64.7%, respectively. The calculated emission cross section of 1200 °C for 5 h was up to 4.4 × 10-20 cm2. In X-ray photoelectron spectroscopy, the concentrations of oxygen vacancies reduced from 1.28% down to absence by annealing. These experiments show that color centers are detrimental to the optical properties of HDS-Yb:YAG laser crystal and optimal annealing treatments should be conducted.

  9. Crystal structure and high temperature transport properties of Yb-filled p-type skutterudites Yb{sub x}Co{sub 2.5}Fe{sub 1.5}Sb{sub 12}

    SciTech Connect

    Dong, Yongkwan; Puneet, Pooja; Tritt, Terry M.; Nolas, George S.

    2014-01-15

    Partially Yb-filled Fe substituted polycrystalline p-type skutterudites with nominal compositions Yb{sub x}Co{sub 2.5}Fe{sub 1.5}Sb{sub 12}, with varying filler concentrations x, were synthesized by reacting the constituent elements and subsequent solid state annealing, followed by densification by hot-pressing. The compositions and filling fractions were confirmed with a combination of Rietveld refinement and elemental analysis. Their thermoelectric properties were evaluated from 300 to 800 K. The Seebeck coefficients for the specimens increase with increasing temperature and plateau at around 750 K. The thermal conductivity decreases with increasing Yb filling fraction, and bipolar conduction becomes evident and increases at elevated temperatures. A maximum ZT value of 0.8 was obtained at 750 K for Yb{sub 0.47}Co{sub 2.6}Fe{sub 1.4}Sb{sub 12}. The thermoelectric properties and potential for further optimization are discussed in light of our results. - Graphical abstract: Display Omitted - Highlights: • Yb-filled Fe-substituted p-type CoSb{sub 3} skutterudites, Yb{sub x}Co{sub 2.5}Fe{sub 1.5}Sb{sub 12}, were structurally and physically characterized. • Both filling fraction and Co-to-Fe ratio affect the transport properties. • High ZT was obtained for the composition with ∼50% Yb filling and a slightly lower than nominal Fe content.

  10. Influence of saturation of diode pump radiation absorption in YAG:Yb+3 crystal on parameters of planar waveguide lasers

    NASA Astrophysics Data System (ADS)

    Galushkin, M. G.; Yakunin, V. P.; Dyachkov, R. G.

    2017-01-01

    A method has been devised for calculating the energy parameters of generation of planar YAG:Yb3+ lasers, with regard to saturation of the absorption of pump diode laser radiation with a wavelength λ  =  940 nm. It has been shown that nonlinearity of the pump absorption coefficient can substantially reduce the small-signal gain at the transition with a wavelength λ  =  1030 nm. It has been found that pump saturation influence on the energy efficiency of planar lasers and power amplifiers is considerably weakened in the field of intense laser radiation.

  11. Comparative thermal analysis of Nd- and Yb-doped YAG and KGdW laser crystals under diode- and flashlamp-pumping

    NASA Astrophysics Data System (ADS)

    Loiko, P. A.; Yumashev, K. V.; Kuleshov, N. V.; Pavlyuk, A. A.

    2012-10-01

    Temperature distribution in the Nd- and Yb- doped YAG and KGdW laser crystals under flashlamp- and diode-pumping was characterized by means of finite element analysis. For KGdW, two laser crystal orientations were considered for light propagation along the Np and Ng optical indicatrix axes, taking into account the anisotropy of thermal conductivity coefficient. The influence of the cooling conditions, pump spot size and dopant concentration on the temperature distribution was analyzed. For flashlamp-pumping conditions, the applicability of the quasi-steady-state model is discussed. The main concerns in the thermal management of KGdW laser host is the relatively low thermal conductivity that results in poor cooling and significant absorption coefficients under diode pumping that result in highly non-uniform volumetric heat deposition. "Athermal" Ng-cut KGdW crystal was found to produce higher temperature gradients that the "standard" Np-cut one, that should results in higher internal stresses and higher probability of thermally-induced cracks.

  12. Critical magnetic scattering in geometric frastrated multiferroic LuMnO3

    NASA Astrophysics Data System (ADS)

    Yano, Shinichiro; Li, Bing; Louca, Despina; Qiu, Yiming; Copley, John

    2013-03-01

    The coexistence of competing order parameters in the class of materials referred to as the multiferroics is of great interest. The hexagonal manganites AMnO3 (A = Y, Lu, Ho and Yb) with the P63cm space group exhibit a ferroelectric transition, at very high temperatures, typically ~ 1000 K, while the antiferromagnetic transition, TN, occurs at ~ 100K. Earlier studies on YMnO3 and LuMnO3 using neutron scattering on single crystals showed that diffuse scattering is present around the forbidden nuclear (100) Bragg peak which corresponds to Q=1.20 Å-1.Its intensity rises very sharply and drops just around TN. We performed inelastic neutron scattering measurement on a powder sample of LuMnO3 form 4 to 250 K using the DCS at NIST. Strong inelastic intensity, not due to magnon excitations, is observed at Q=1.32 and 2.50 Å-1. With cooling, the intensity gradually rises and reaches a peak around 100 K. Below, it drops drastically once the system orders. This kind of scattering is due to critical scattering arising from magnetic fluctuations above TN. The S(Q, ω) is asymmetric suggesting that the Mn spin correlations are mosmost likely 2-dimensional in nature.

  13. High temperature transport properties of co-substituted Ca{sub 1−x}Ln{sub x}Mn{sub 1−x}Nb{sub x}O{sub 3} (Ln = Yb, Lu; 0.02 ≤ x ≤ 0.08)

    SciTech Connect

    Nag, Abanti Bose, Rapaka S.C.

    2016-02-15

    Highlights: • The thermoelectric Ca{sub 1−x}Ln{sub x}Mn{sub 1−x}Nb{sub x}O{sub 3} (Ln = Yb, Lu) perovskite are prepared by solid state reaction. • The high temperature transport properties are explored. • The co-substituted Ca{sub 1−x}Ln{sub x}Mn{sub 1−x}Nb{sub x}O{sub 3} shows non-metal-like temperature dependence of resistivity. • The Seebeck coefficient of Ca{sub 1−x}Ln{sub x}Mn{sub 1−x}Nb{sub x}O{sub 3} exhibits metallic nature. • The puzzling transport phenomenon is originated from oxygen vacancy related defect centres. - Abstract: The co-substituted Ca{sub 1−x}Ln{sub x}Mn{sub 1−x}Nb{sub x}O{sub 3} (Ln = Yb, Lu; 0.02 ≤ x ≤ 0.08) are synthesized by solid-state reaction and the electronic transport properties are investigated. Rietveld refinement confirms the formation of single phase orthorhombic structure with gradual increase of cell parameters with doping level. The electronic transport properties such as Seebeck coefficient and electrical resistivity decrease with increasing the dopant concentration for both the co-substituted compositions. All the compositions of Ca{sub 1−x}Ln{sub x}Mn{sub 1−x}Nb{sub x}O{sub 3} show nonmetal-like temperature dependence of resistivity; whereas metal-like temperature dependence of thermopower. This inconsistency is explained by the formation of oxygen vacancy associated defect centres that originates from partial reduction of Mn{sup 4+} to Mn{sup 3+} due to co-substitution. The defect centres act as extrinsic carriers and cause additional contribution to the entropy of the system, leading to increase of Seebeck coefficient as a function of temperature. The transport mechanism of charge carriers is explained in the framework of Mott’s small polaron hopping mechanism.

  14. Effect of inclining strain on the crystal lattice along an extended series of lanthanide hydroxysulfates Ln(OH)SO4 (Ln = Pr-Yb, except Pm).

    PubMed

    Zehnder, Ralph A; Wilson, Christopher S; Christy, Hunter T; Harris, Kenneth S; Chauhan, Varun; Schutz, Victor; Sullivan, Matthew; Zeller, Matthias; Fronczek, Frank R; Myers, Jacob A; Dammann, Kyle; Duck, James; Smith, Peter M; Okuma, Antony; Johnson, Kristin; Sovesky, Robert; Stroudt, Cameron; Renn, Robert A

    2011-02-07

    A series of trivalent lanthanide hydroxysulfates, Ln(OH)SO(4), (Ln = Pr through Yb, except radioactive Pm) has been synthesized via hydrothermal methods from Ln(2)(SO(4))(3)·8H(2)O by reaction with aqueous NaOH at 170 °C in Teflon lined Parr steel autoclaves, and were characterized by single crystal X-ray diffraction and FT-IR spectroscopy. Two types of arrangements were found in the solid state. The lighter (Ln = Pr-Nd, Sm-Gd) and heavier lanthanide(III) hydroxysulfates (Tb-Yb) are each isostructural. Both structure types exhibit the monoclinic space group P2(1)/n, but the unit cell content is doubled with two crystallographically distinct LnO(8) polyhedra for the heavier lanthanide compounds. The lighter complexes maintain the coordination number 9, forming a three-dimensional extended lattice. The heavier counterparts exhibit the coordination number 8, and arrange as infinite columns of two crystallographically different LnO(8) polyhedra, while extending along the "c" axis. These columns of LnO(8) polyhedra are surrounded and separated by six columns of sulfate ions, also elongating in the "c" direction. The rigid sulfate entities seem to obstruct the closing in of the lighter LnO(9) polyhedra, and show an inclining degree of torsion into the "ac" layers. The crystal lattice of the lighter 4f complexes can sufficiently withstand the tension buildup, caused by the decreasing Ln(3+) radius, up to Gd(OH)SO(4). The energy profile of this structural arrangement then seems to exceed levels at which this structure type is favorable. The lattice arrangement of the heavier Ln-analogues seems to offer a lower energy profile. This appears to be the preferred arrangement for the heavier lanthanide hydroxysulfates, whose crystal lattice exhibits more flexibility, as the coordination sphere of these analogues is less crowded. The IR absorbance frequencies of the hydroxide ligands correlate as a function of the Ln(3+) ionic radius. This corresponds well with the X-ray single

  15. Specific radioactivity of neutron induced radioisotopes: assessment methods and application for medically useful 177Lu production as a case.

    PubMed

    Le, Van So

    2011-01-19

    The conventional reaction yield evaluation for radioisotope production is not sufficient to set up the optimal conditions for producing radionuclide products of the desired radiochemical quality. Alternatively, the specific radioactivity (SA) assessment, dealing with the relationship between the affecting factors and the inherent properties of the target and impurities, offers a way to optimally perform the irradiation for production of the best quality radioisotopes for various applications, especially for targeting radiopharmaceutical preparation. Neutron-capture characteristics, target impurity, side nuclear reactions, target burn-up and post-irradiation processing/cooling time are the main parameters affecting the SA of the radioisotope product. These parameters have been incorporated into the format of mathematical equations for the reaction yield and SA assessment. As a method demonstration, the SA assessment of 177Lu produced based on two different reactions, 176Lu (n,γ)177Lu and 176Yb (n,γ) 177Yb (β- decay) 177Lu, were performed. The irradiation time required for achieving a maximum yield and maximum SA value was evaluated for production based on the 176Lu (n,γ)177Lu reaction. The effect of several factors (such as elemental Lu and isotopic impurities) on the 177Lu SA degradation was evaluated for production based on the 176Yb (n,γ) 177Yb (β- decay) 177Lu reaction. The method of SA assessment of a mixture of several radioactive sources was developed for the radioisotope produced in a reactor from different targets.

  16. New rare earth metal-rich indides RE14Ni 3In 3 ( RE=Sc, Y, Gd-Tm, Lu)—synthesis and crystal chemistry

    NASA Astrophysics Data System (ADS)

    Lukachuk, Mar'yana; Galadzhun, Yaroslav V.; Zaremba, Roman I.; Dzevenko, Mariya V.; Kalychak, Yaroslav M.; Zaremba, Vasyl I.; Rodewald, Ute Ch.; Pöttgen, Rainer

    2005-09-01

    The rare earth-nickel-indides RE14Ni 3In 3 ( RE=Sc, Y, Gd-Tm, Lu) were synthesized from the elements by arc-melting and subsequent annealing. The compounds were investigated on the basis of X-ray powder and single crystal data: Lu 14Co 2In 3 type, P4 2/ nmc, Z=4, a=888.1(1), c=2134.7(4), wR2=0.0653, 1381 F2 values, 63 variables for Sc 13.89Ni 3.66In 2.45; a=961.2(1), c=2316.2(5), wR2=0.0633, 1741 F2 values, 64 variables for Y 13.84Ni 3.19In 2.97; a=965.3(1), c=2330.5(5), wR2=0.0620, 1765 F2 values, 63 variables for Gd 14Ni 3.29In 2.71; a=956.8(1), c=2298.4(5), wR2=0.0829, 1707 F2 values, 64 variables for Tb 13.82Ni 3.36In 2.82; a=951.7(1), c=2289.0(5), wR2=0.0838, 1794 F2 values, 64 variables for Dy 13.60Ni 3.34In 3.06; a=948.53(7), c=2270.6(1), wR2=0.1137, 1191 F2 values, 64 variables for Ho 13.35Ni 3.17In 3.48; a=943.5(1), c=2269.1(5), wR2=0.0552, 1646 F2 values, 64 variables for Er 13.53Ni 3.14In 3.33; a=938.42(7), c=2250.8(1), wR2=0.1051, 1611 F2 values, 64 variables for Tm 13.47Ni 3.28In 3.25; a=937.3(1), c=2249.6(5), wR2=0.0692, 1604 F2 values, 64 variables for Tm 13.80Ni 3.49In 2.71; and a=933.4(1), c=2263.0(5), wR2=0.0709, 1603 F2 values, 64 variables for Lu 13.94Ni 3.07In 2.99. The RE14Ni 3In 3 indides show significant Ni/In mixing on the 4 c In1 site. Except the gadolinium compound, the RE14Ni 3In 3 intermetallics also reveal RE/In mixing on the 4 c RE1 site, leading to the refined compositions. Due to the high rare earth metal content, the seven crystallographically independent RE sites have between 9 and 10 nearest RE neighbors. The RE14Ni 3In 3 structures can be described as a complex intergrowth of rare earth-based polyhedra. Both nickel sites have a distorted trigonal-prismatic rare earth coordination. An interesting feature is the In2-In2 dumb-bell at an In2-In2 distance of 304 pm (for Gd 14Ni 3.29In 2.71). The crystal chemical peculiarities of the RE14Ni 3In 3 indides are briefly discussed.

  17. Growth conditions, structure, Raman characterization and optical properties of Sm-doped (Lu{sub x}Gd{sub 1-x}){sub 2}SiO{sub 5} single crystals grown by the Czochralski method

    SciTech Connect

    GLowacki, MichaL; Runka, Tomasz; Drozdowski, MirosLaw; Domukhovski, Viktor; Berkowski, Marek

    2012-02-15

    The (Lu{sub x}Gd{sub 0.995-x}Sm{sub 0.005}){sub 2}SiO{sub 5} single crystals with x=0.095, 0.11, 0.15, 0.17, 0.19 0.35 and 0.5 were grown by the Czochralski method. Structural properties were investigated by X-ray diffraction measurements. Unit cell parameters and cell volume were determined by the Rietveld refinement of the collected X-ray powder spectra. The segregation features between Gd and Lu were estimated and analyzed. Vibrational properties of the solid solutions were analyzed on the basis of polarized Raman spectra acquired at 300-875 K temperature range. Absorption and emission spectra of Sm{sup 3+} ion in the crystals with different composition were analyzed in the terms of dopant energy levels, oscillator strengths of transitions and spectral features of luminescence bands in the visible range. Both structural and optical investigations revealed that change of Lu{sup 3+} content in (Lu{sub x}Gd{sub 0.995-x}Sm{sub 0.005}){sub 2}SiO{sub 5} solid solution crystals induces the phase transition from C2/c (Lu{sub 2}SiO{sub 5}) to P2{sub 1}/c (Gd{sub 2}SiO{sub 5}) structure. It was found that the break of LSO to GSO-type structure occurs at 0.15crystals of Sm{sup 3+}-doped (Lu{sub x}Gd{sub 1-x}){sub 2}SiO{sub 5} solid solutions have been grown by Czochralski method and characterized by various techniques. Crystal structure changes from C2/c to P2{sub 1}/c for composition with 0.15crystal structure causes changes in emission spectra. Highlights: Black-Right-Pointing-Pointer The (Lu{sub x}Gd{sub 1-x}){sub 2}SiO{sub 5} crystals are an alternative to LSO and GSO hosts for applications. Black-Right-Pointing-Pointer The break of the P2{sub 1}/c to C2/c structure in (Lu{sub x}Gd{sub 1-x}){sub 2}SiO{sub 5}:Sm occurs for 0.15

  18. Ternary rare earth silicides RE2M3Si4 (RE = Sc, Y, Lu; M = Mo, W): crystal structure, coloring and electronic properties.

    PubMed

    Nielsen, Morten B; Xie, Weiwei; Cava, Robert J

    2016-03-07

    The ternary compounds Sc2Mo3Si4, Y2Mo3Si4, Lu2Mo3Si4 and Sc2W3Si4 have been synthesized using arc melting and structurally characterized using single crystal X-ray diffraction. The compounds are isostructural with Gd5Si4 but with coloring (order of the rare earth and transition metals) on the Gd site. In contrast to group 4 and 5 ternaries of the same type, we observe no site mixing between the rare earth and transition metals. The Y compound displays a different, less common coloring from the others and through DFT calculations and investigation of the solid solution between Sc2Mo3Si4 and Y2Mo3Si4 it is shown that the different coloring of the latter is only marginally more stable. The electronic structures of the ternary compounds have been investigated using DFT calculations, yielding densities of states very similar to Gd5Si4. These predict metallic behavior and no magnetism, which is confirmed through resistivity and magnetization measurements.

  19. Nanostructured crystals of fluorite phases Sr1 - x R x F2 + x and their ordering: 7. A procedure for cluster modeling of Sr1 - x R x F2 + x Based on the Structure of an Ordered Phase ( R = Lu)

    NASA Astrophysics Data System (ADS)

    Sul'yanova, E. A.; Verin, I. A.; Sobolev, B. P.

    2012-01-01

    Single crystals of the Sr1 - x Lu x F2 + x nonstoichiometric phase ( x = 0.095 and 0.189), which crystallizes in the CaF2 structure type (space group Fm bar 3 m), are studied by X-ray diffraction. A procedure for the cluster modeling of Sr1 - x Lu x F2 + x based on the fine structural features of the Sr4Lu3F17 stoichiometric compound with a fluorite derivative structure (one of the ordered phases in the SrF2-LuF3 system) is proposed. The description of the structure of the Sr1- x Lu x F2+ x solid solutions is based on the octacubic configuration of the { M 14 - n R n F64 + n } defect cluster. Structural data on the displacements of cations and anions in the ordered Sr4Lu3F17 phase (in relation to the undistorted fluorite phase) allow one to identify the distortions of the crystal lattice of the disordered (nonstoichiometric) Sr1- x Lu x F2 + x phase.

  20. Enhanced 2.7 μm mid-infrared emissions of Er3+ via Pr3+ deactivation and Yb3+ sensitization in LiNbO3 crystal.

    PubMed

    Zhang, Peixiong; Chen, Zhenqiang; Hang, Yin; Li, Zhen; Yin, Hao; Zhu, Siqi; Fu, Shenhe; Li, Anming

    2016-10-31

    The use of Pr3+ codoping for enhancement of the transition of Er3+: 4I11/24I13/2 2.7 μm emissions was investigated in the Er/Yb codoped LiNbO3 crystal for the first time. It is found that the codoped of Pr3+ ion in Er3+, Yb3+ and Pr3+ triply doped LiNbO3 crystal (Er/Yb/Pr: LN) greatly enhances Er3+: 2.7 μm emission under excitation of a common 970 nm laser diode, depopulates the lower laser level of Er3+:4I13/2, and has little influence on the higher laser level of Er3+:4I11/2 at the same time for population inversion. The 2.7 μm emission characteristics and energy transfer were investigated in detail. The energy transition efficiency from lower laser level of Er3+:4I13/2 to Pr3+:3F4 level is as high as 0.42, indicating that the Pr3+ ion is an effective deactivation ion for Er3+ ion in LiNbO3 crystal. These results suggest that Er/Yb/Pr: LiNbO3 crystal may become an attractive host for developing solid state lasers at around 2.7 μm under a conventional 970 nm LD pump.

  1. Up-conversion in sol-gel derived nano-glass-ceramics comprising NaYF 4 nano-crystals doped with Yb 3+, Ho 3+ and Tm 3+

    NASA Astrophysics Data System (ADS)

    Santana-Alonso, A.; Méndez-Ramos, J.; Yanes, A. C.; del-Castillo, J.; Rodríguez, V. D.

    2010-07-01

    NaYF 4 is an excellent host material for rare-earth ions presenting very high efficiencies in up-conversion processes. Thus, nano-glass-ceramics containing NaYF 4 nano-crystals emerge as promising candidates for general lighting appliances and integrated optical devices. Here we report highly transparent sol-gel derived nano-glass-ceramics comprising Yb 3+-Ho 3+ and Yb 3+-Ho 3+-Tm 3+ co-doped NaYF 4 nano-crystals. A structural analysis by means of X-ray diffraction measurements confirmed the formation of NaYF 4 nano-crystals during thermal treatment. Luminescence features have been related to the crystallinity degree of the samples. Violet, blue, green and red up-conversion emissions were obtained under infrared excitation at 980 nm and corresponding mechanisms involved have been analysed. Additionally, the total visible up-conversion emission has been quantified in terms of the standard chromaticity coordinates. In particular, an overall colour emission, very close to the standard equal energy white-light illumination point of the chromaticity diagram, was obtained in the Yb 3+-Ho 3+-Tm 3+ triply-doped samples.

  2. Analysis of excitation mechanisms of Ho3+ upconversion luminescence in Ho3+:LiYbF4 (0.2 at %) crystal via photographs of its longitudinal cross sections and via spectral and kinetic characteristics

    NASA Astrophysics Data System (ADS)

    Kazakov, B. N.; Mikheev, A. V.; Goriev, O. G.; Korableva, S. L.; Semashko, V. V.

    2016-10-01

    The results of a complex analysis of the excitation mechanisms of the up conversion luminescence of Ho3+:LiYbF4 (0.2 at %) crystal are presented. The spatial distribution of the upconversion luminescence intensity is studied by the photographs of longitudinal cross sections at different positions of the laser beam waist with respect to the sample. The surface power density of the pump laser diode radiation (0.755 W, λ = 933 nm) was changed by focusing the beam (similar to Z-scanning). The dependences of the longitudinal luminescence cross sections, as well as of the spectral and kinetic characteristics of Ho3+ and Yb3+ luminescence, on the position of the laser beam waist are determined. It is found that there exist two different mechanisms of the population of the energy levels of Ho3+ ions from which green and red luminescence occur, namely, cooperative sensitization of luminescence and absorption of induced photon groups (JETP Letters, 102 (5), 279 (2015)). It is shown that the contributions of these mechanisms vary both in time and over the crystal volume. All the observed spatial, spectral, and temporal specific features of the upconversion luminescence of Ho3+:LiYbF4 (0.2 at %) crystal are qualitatively explained.

  3. Equiatomic intermetallic compounds REPtMg (RE = Y, Eu, Tb-Tm, Lu) - Structure and magnetism

    NASA Astrophysics Data System (ADS)

    Stein, Sebastian; Heletta, Lukas; Block, Theresa; Gerke, Birgit; Pöttgen, Rainer

    2017-05-01

    Eight new equiatomic REPtMg intermetallics with RE = Y, Eu, Tb-Tm, Lu were synthesized from the elements in sealed niobium ampoules (induction melting followed by different annealing sequences). All samples were characterized through X-ray powder patterns and the structures of YPtMg, EuPtMg, DyPtMg, HoPtMg and TmPtMg were refined from single crystal X-ray diffractometer data. The REPtMg phases crystallize with two different structure types. The representatives with RE = Y, Tb-Ho crystallize with the hexagonal ZrNiAl type, space group P 6 bar 2 m , while those with RE = Eu, Yb and Lu adopt the orthorhombic TiNiSi type, space group Pnma. ErPtMg and TmPtMg are dimorphic with a ZrNiAl type high and a TiNiSi type low-temperature modification. Temperature-dependent magnetic susceptibility measurements indicate Pauli paramagnetism for YPtMg and LuPtMg while EuPtMg, TbPtMg, DyPtMg and HoPtMg are Curie-Weiss paramagnets. Antiferromagnetic (TN = 12.6 K for EuPtMg) respectively ferromagnetic ordering (TC = 56.3 K for TbPtMg, 28.8 K for DyPtMg and 19.9 K for HoPtMg) occurs in the low-temperature regime. 151Eu Mössbauer spectra confirm divalent europium (δ = -8.03 mm s-1 at 78 K) in EuPtMg and show strong magnetic hyperfine field splitting below the Néel temperature.

  4. Highly uniform and monodisperse beta-NaYF(4):Ln(3+) (Ln = Eu, Tb, Yb/Er, and Yb/Tm) hexagonal microprism crystals: hydrothermal synthesis and luminescent properties.

    PubMed

    Li, Chunxia; Quan, Zewei; Yang, Jun; Yang, Piaoping; Lin, Jun

    2007-08-06

    beta-NaYF4:Ln3+ (Ln = Eu, Tb, Yb/Er, and Yb/Tm) hexagonal microprisms with remarkably uniform morphology and size have been synthesized via a facile hydrothermal route. X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), high-resolution transmission electron microscopy (HRTEM), and photoluminescence (PL) spectra as well as kinetic decays were used to characterize the samples. It is found that sodium citrate as a shape modifier introduced into the reaction system plays a critical role in the shape evolution of the final products. Furthermore, the shape and size of the products can be further manipulated by adjusting the molar ratio of citrate/RE3+ (RE represents the total amount of Y3+ and the doped rare earth elements such as Eu3+, Tb3+, Yb3+/Er3+, or Yb3+/Tm3+). Under the excitation of 397 nm ultraviolet light, NaYF4:xEu3+ (x = 1.5, 5%) shows the emission lines of Eu3+ corresponding to 5D0-3 --> 7FJ (J = 0-4) transitions from 400 to 700 nm (whole visible spectral region) with different intensity, resulting in yellow and red down-conversion (DC) light emissions, respectively. When doped with 5% Tb3+ ions, the strong DC fluorescence corresponding to 5D4 --> 7FJ (J = 6, 5, 4, 3) transitions with 5D4 --> 7F5 (green emission at 544 nm) being the most prominent group that has been observed. In addition, under 980 nm laser excitation, the Yb3+/Er3+- and Yb3+/Tm3+-codoped beta-NaYF4 samples exhibit bright green and whitish blue up-conversion (UC) luminescence, respectively. The luminescence mechanisms for the doped lanthanide ions were thoroughly analyzed.

  5. Quasi four-level Tm:LuAG laser

    NASA Technical Reports Server (NTRS)

    Jani, Mahendra G. (Inventor); Barnes, Norman P. (Inventor); Hutcheson, Ralph L. (Inventor); Rodriguez, Waldo J. (Inventor)

    1997-01-01

    A quasi four-level solid-state laser is provided. A laser crystal is disposed in a laser cavity. The laser crystal has a LuAG-based host material doped to a final concentration between about 2% and about 7% thulium (Tm) ions. For the more heavily doped final concentrations, the LuAG-based host material is a LuAG seed crystal doped with a small concentration of Tm ions. Laser diode arrays are disposed transversely to the laser crystal for energizing the Tm ions.

  6. /sup 176/Lu: Cosmic clock or stellar thermometer

    SciTech Connect

    Beer, H.; Kaeppeler, F.; Wisshak, K.; Ward, R.A.

    1981-08-01

    We quantitatively examine the various experimental and theoretical aspects of the stellar synthesis of the long-lived ground state of /sup 176/LU (3.6 x 10/sup 10/ yr). We discuss the various regimes of stellar temperature and free-neutron density in which either (i) the internal electromagnetic couplings between /sup 176/Lu/sup o/ and /sup 176/Lu/sup m/ (3.68 hr) are sufficiently low that they may be treated as separate nuclei, or (ii) the internal couplings are rapidly able to establish thermal equilibrium between /sup 176/Lu/sup o/ and /sup 176/Lu/sup m/. Case (i) above allows /sup 176/Lu/sup o/ to be used as a cosmic clock of galactic s-process nucleosynthesis. As experimental input to the cosmic clock, we have measured the 30 keV neutron capture cross sections: sigma(/sup 170/Yb) = 766 +- 30 mb and sigma(/sup 175/Lu) = 1266 +- 43 mb. This latter value also yields the branching ratio, B, to /sup 176/Lu/sup o/ from neutron capture on /sup 175/Lu as B(24 keV) = 0.362 +- 0.038. Using abundance and cross-section systematics, we derive an upper limit on the mean s-process age of solar material of 11 x 10/sup 9/ yr before the solidification of the meteorites. By requiring the solar abundance of /sup 170/Yb to be consistent with these same sigmaN systematics, we can also bracket the allowable range for the average s-process neutron density as 10/sup 7/ cm/sup -3/< or approx. =< or approx. =4 x 10/sup 7/ cm)/sup 3/. However, for sufficiently high stellar temperatures, case (ii) above implies that the total effective half-life of /sup 176/Lu against beta decay becomes a very strong function of the stellar temperature: t/sub 1/2/(/sup 176/Lu) = 18.5 exp (14.7/T/sub 8/) hr for T/sub 8/>1, and thus the /sup 176/Lu ..-->.. /sup 176/Hf decay would constitute a sensitive stellar s-process thermometer. We show that the fact that /sup 176/Lu does exist in the solar system can place firm constraints on the temperature and neutron density of current models for the site of the

  7. Dynamically Tuning the Up-conversion Luminescence of Er3+/Yb3+ Co-doped Sodium Niobate Nano-crystals through Magnetic Field

    NASA Astrophysics Data System (ADS)

    Xiao, Quanlan; Zhang, Yuanhao; Zhang, Han; Dong, Guoping; Han, Junbo; Qiu, Jianrong

    2016-08-01

    In this work, we show here that the up-conversion luminescence of NaNbO3:Er3+/Yb3+ nano-materials can be modulated by magnetic field and a enhancement of up-conversion intensities by a factor of about 2 for Er3+:4S3/2 → 4I15/2 obtained at 30 T and about 5.4 for Er3+:4F9/2 → 4I15/2 obtained at 20 T. The increased up-conversion luminescence are mainly interpreted in terms of the enhanced non-radiation transition from 4I11/2 to 4I13/2 of Er3+ ions and the spin-orbital coupling (that is “mixing” effect) in crystal field by an external magnetic field. Meanwhile, we observed continuously spectra broadening with growing the magnetic field intensity, which is ascribed to the “mixing” effect induced by magnetic field and the difference of g factor of sub-bands. This bi-functional material with controllable optical-magnetic interactions has various potential applications, such as optical detection of magnetic field, etc.

  8. Dynamically Tuning the Up-conversion Luminescence of Er(3+)/Yb(3+) Co-doped Sodium Niobate Nano-crystals through Magnetic Field.

    PubMed

    Xiao, Quanlan; Zhang, Yuanhao; Zhang, Han; Dong, Guoping; Han, Junbo; Qiu, Jianrong

    2016-08-09

    In this work, we show here that the up-conversion luminescence of NaNbO3:Er(3+)/Yb(3+) nano-materials can be modulated by magnetic field and a enhancement of up-conversion intensities by a factor of about 2 for Er(3+):(4)S3/2 → (4)I15/2 obtained at 30 T and about 5.4 for Er(3+):(4)F9/2 → (4)I15/2 obtained at 20 T. The increased up-conversion luminescence are mainly interpreted in terms of the enhanced non-radiation transition from (4)I11/2 to (4)I13/2 of Er(3+) ions and the spin-orbital coupling (that is "mixing" effect) in crystal field by an external magnetic field. Meanwhile, we observed continuously spectra broadening with growing the magnetic field intensity, which is ascribed to the "mixing" effect induced by magnetic field and the difference of g factor of sub-bands. This bi-functional material with controllable optical-magnetic interactions has various potential applications, such as optical detection of magnetic field, etc.

  9. Dynamically Tuning the Up-conversion Luminescence of Er3+/Yb3+ Co-doped Sodium Niobate Nano-crystals through Magnetic Field

    PubMed Central

    Xiao, Quanlan; Zhang, Yuanhao; Zhang, Han; Dong, Guoping; Han, Junbo; Qiu, Jianrong

    2016-01-01

    In this work, we show here that the up-conversion luminescence of NaNbO3:Er3+/Yb3+ nano-materials can be modulated by magnetic field and a enhancement of up-conversion intensities by a factor of about 2 for Er3+:4S3/2 → 4I15/2 obtained at 30 T and about 5.4 for Er3+:4F9/2 → 4I15/2 obtained at 20 T. The increased up-conversion luminescence are mainly interpreted in terms of the enhanced non-radiation transition from 4I11/2 to 4I13/2 of Er3+ ions and the spin-orbital coupling (that is “mixing” effect) in crystal field by an external magnetic field. Meanwhile, we observed continuously spectra broadening with growing the magnetic field intensity, which is ascribed to the “mixing” effect induced by magnetic field and the difference of g factor of sub-bands. This bi-functional material with controllable optical-magnetic interactions has various potential applications, such as optical detection of magnetic field, etc. PMID:27502356

  10. CaF2:Yb laser ceramics

    NASA Astrophysics Data System (ADS)

    Akchurin, M. Sh.; Basiev, T. T.; Demidenko, A. A.; Doroshenko, M. E.; Fedorov, P. P.; Garibin, E. A.; Gusev, P. E.; Kuznetsov, S. V.; Krutov, M. A.; Mironov, I. A.; Osiko, V. V.; Popov, P. A.

    2013-01-01

    CaF2:Yb fluoride laser ceramics, prepared by hot-forming, exhibit the same optical properties as starting single crystals. Slope efficiency of the Сa0.95Yb0.05F2.05 is equal to 35% in the pulsed mode of laser operation. Decrease of ytterbium concentration in CaF2:Yb samples down to 3 mol.% resulted in the essential improvement of Сa0.97Yb0.03F2.03 thermal conductivity from 3.5 to 4.5 W/m K, but slightly decreased (down to 30%) slope efficiency of the samples under both pulsed and CW mode of operation. Alternative hot-pressing synthesis of CaF2:Yb fluoride laser ceramics provided materials with superior mechanical properties (microhardness Н = 3.2 GPa and fracture toughness К1С = 0.65 МPа m1/2) in comparison with hot-formed and/or single crystal CaF2:Yb specimens. For the first time, lasing has been observed for the novel aforementioned hot-pressed CaF2:Yb ceramics.

  11. Structure and bonding in Yb4MgGe4: Yb2+/Yb3+ mixed-valency and charge separation.

    PubMed

    Tobash, Paul H; Bobev, Svilen

    2006-03-22

    Reported are the synthesis and the structural characterization of a new derivative of the RE5Tt4 family (RE = Rare-earth; Tt = Tetrel, = Si, Ge, i.e., group 14 element), Yb5-xMgxGe4 (x approximately 1). Crystal data for Yb4.04(1)Mg0.96(1)Ge4 at 23 degrees C: orthorhombic, space group Pnma (No. 62), Z = 4; a = 7.155(2) A, b = 14.769(5) A, c = 7.688(2) A; V = 812.5(4) A3. This phase is an example of a substitution of lanthanide metal (Yb) with a nonmagnetic element (Mg) within this structure type. Its structure can alternatively be described as an intergrowth of the hypothetical Yb2MgGe2, which features flat infinite [MgGe2]4- layers and the hypothetical YbGe with [Ge2]6- dimers. The flat [MgGe2]4- layers propagate in two dimensions (a and c), and they are offset by a distance of 1/4.a with respect to one another and are interspaced with layers of [Ge2]6- dimers and Yb cations filling the space between them. According to the structural and physical property data, Yb4MgGe4 is a heterogeneous mixed-valent compound, i.e. a system where one of the two symmetry-inequivalent Yb sites has atoms in closed-shell Yb2+ configuration, whereas the Yb3+ cations occupy a different crystallographic site.

  12. Multiband electronic transport in α-Yb1-x Sr x AlB4 [x  =  0, 0.19(3)] single crystals

    NASA Astrophysics Data System (ADS)

    Ryu, Hyejin; Abeykoon, Milinda; Bozin, Emil; Matsumoto, Yosuke; Nakatsuji, S.; Petrovic, C.

    2016-10-01

    We report on the evidence for the multiband electronic transport in α-YbAlB4 and α-Yb0.81(2)Sr0.19(3)AlB4. Multiband transport reveals itself below 10 K in both compounds via Hall effect measurements, whereas anisotropic magnetic ground state sets in below 3 K in α-Yb0.81(2)Sr0.19(3)AlB4. Our results show that Sr2+ substitution enhances conductivity, but does not change the quasiparticle mass of bands induced by heavy fermion hybridization.

  13. Multiband electronic transport in α-Yb1₋xSrx AlB4 [ x = 0, 0.19(3)] single crystals

    DOE PAGES

    Ryu, Hyejin; Abeykoon, Milinda; Bozin, Emil; ...

    2016-08-19

    Here we report on the evidence for the multiband electronic transport in α- YbAlB4 and α-Yb0.81(2)Sr0.19(3)AlB4. Multiband transport reveals itself below 10 K in both compounds via Hall effect measurements, whereas anisotropic magnetic ground state sets in below 3 K in α-Yb0.81(2)Sr0.19(3)AlB4. Our results show that Sr2+ substitution enhances conductivity, but does not change the quasiparticle mass of bands induced by heavy fermion hybridization.

  14. Hybrid 2D photonic crystal-assisted Lu3Al5O12:Ce ceramic-plate phosphor and free-standing red film phosphor for white LEDs with high color-rendering index.

    PubMed

    Park, Hoo Keun; Oh, Ji Hye; Kang, Heejoon; Zhang, Jian; Do, Young Rag

    2015-03-04

    This paper reports the combined optical effects of a two-dimensional (2D) SiNx photonic crystal layer (PCL)-assisted Lu3Al5O12:Ce (LuAG:Ce) green ceramic-plate phosphor (CPP) and a free-standing (Sr,Ca)AlSiN3:Eu red film phosphor to enhance luminous efficacy, color rendering index (CRI), and special CRI (R9) of LuAG:Ce CPP-capped white light-emitting diodes (LEDs) for high-power white LEDs at 350 mA. By introducing the 2D SiNx PCL, the luminous efficacy was improved by a factor of 1.25 and 1.15 compared to that of the conventional flat CPP-capped LED and the thickness-increased CPP-capped LED (with a thickness of 0.15 mm), respectively, while maintaining low color-rendering properties. The combining of the free-standing red film phosphor in the flat CPP-capped, the 2D PCL-assisted CPP-capped, and the thickness-increased CPP-capped LEDs led to enhancement of the CRI and the special CRI (R9); it also led to a decrease of the correlated color temperature (CCT) due to broad wavelength coverage via the addition of red emission. High CRI (94), natural white CCT (4450 K), and acceptable luminous efficacy (71.1 lm/W) were attained from the 2D PCL-assisted LuAG:Ce CPP/free-standing red film phosphor-based LED using a red phosphor concentration of 7.5 wt %. It is expected that the combination of the 2D PCL and the free-standing red film phosphor will be a good candidate for achieving a high-power white CPP-capped LED with excellent CRI.

  15. Frequency mixing crystal

    DOEpatents

    Ebbers, Christopher A.; Davis, Laura E.; Webb, Mark

    1992-01-01

    In a laser system for converting infrared laser light waves to visible light comprising a source of infrared laser light waves and means of harmoic generation associated therewith for production of light waves at integral multiples of the frequency of the original wave, the improvement of said means of harmonic generation comprising a crystal having the chemical formula X.sub.2 Y(NO.sub.3).sub.5 .multidot.2 nZ.sub.2 o wherein X is selected from the group consisting of Li, Na, K, Rb, Cs, and Tl; Y is selected from the group consisting of Sc, Y, La, Ce, Nd, Pr, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, Al, Ga, and In; Z is selected from the group consisting of H and D; and n ranges from 0 to 4.

  16. Nonlinear optical crystal optimized for Ytterbium laser host wavelengths

    DOEpatents

    Ebbers, Christopher A.; Schaffers, Kathleen I.

    2007-02-20

    A material for harmonic generation has been made by substitutional changes to the crystal LaCa.sub.4 (BO.sub.3).sub.3 also known as LaCOB in the form Re1.sub.xRe2.sub.yRe3.sub.zCa.sub.4(BO.sub.3).sub.3O where Re1 and Re2, (rare earth ion 1 and rare earth ion 2) are selected from the group consisting of Sc, Yttrium, La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, and Lu; Re3 is Lanthanum; and x+y+z=1.

  17. Nonlinear optical crystal optimized for ytterbium laser host wavelengths

    DOEpatents

    Ebbers, Christopher A.; Schaffers, Kathleen I.

    2007-08-21

    A material for harmonic generation has been made by substitutional changes to the crystal LaCa.sub.4(BO.sub.3).sub.3 also known as LaCOB in the form Re1.sub.xRe2.sub.yRe3.sub.zCa.sub.4(B0.sub.3).sub.3O where Re1 and Re2, (rare earth ion 1 and rare earth ion 2) are selected from the group consisting of Sc, Yttrium, La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, and Lu; Re3 is Lanthanum; and x+y+z=1.

  18. Nonlinear optical crystal optimized for Ytterbium laser host wavelengths

    DOEpatents

    Ebbers, Christopher A.; Schaffers, Kathleen I.

    2008-05-27

    A material for harmonic generation has been made by substitutional changes to the crystal LaCa.sub.4 (BO.sub.3).sub.3 also known as LaCOB in the form Re1.sub.xRe2.sub.yRe3.sub.zCa.sub.4(B0.sub.3).sub.3O where Re1 and Re2, (rare earth ion 1 and rare earth ion 2) are selected from the group consisting of Sc, Yttrium, La, Ce, Pr, Nd, Sm, Eu, Gd, Th, Dy, Ho, Er, Tm, Yb, and Lu; Re3 is Lanthanum; and x+y+z=1.

  19. Raman Investigations of Rare Earth Arsenate Single Crystals

    SciTech Connect

    Barros, G; Santos, C. C.; Ayala, A. P.; Guedes, I.; Boatner, Lynn A; Loong, C. K.

    2010-01-01

    Polarized Raman Spectroscopy was used to investigate the room-temperature phonon characteristics of a series of rare-earth arsenate (REAsO4, RE = Sm, Eu, Gd, Tb, Dy, Ho, Tm, Yb, and Lu) single crystals. The Raman data were interpreted in a systematic manner based on the known tetragonal zircon structure of these compounds, and assignments and correlations were made for the observed bands. We found that the wavenumber of the internal modes of the AsO4 tetrahedron increased with increasing atomic number, and for three out of four lattice wavenumbers observed, this tendency was not nearly so marked as in the case of the internal mode wavenumber.

  20. Nonlinear optical crystal optimized for Ytterbium laser host wavelengths

    DOEpatents

    Ebbers, Christopher A [Pleasanton, CA; Schaffers, Kathleen I [Livermore, CA

    2008-05-27

    A material for harmonic generation has been made by substitutional changes to the crystal LaCa.sub.4 (BO.sub.3).sub.3 also known as LaCOB in the form Re1.sub.xRe2.sub.yRe3.sub.zCa.sub.4(B0.sub.3).sub.3O where Re1 and Re2, (rare earth ion 1 and rare earth ion 2) are selected from the group consisting of Sc, Yttrium, La, Ce, Pr, Nd, Sm, Eu, Gd, Th, Dy, Ho, Er, Tm, Yb, and Lu; Re3 is Lanthanum; and x+y+z=1.

  1. Comparative performance of passively Q-switched diode-pumped Yb:GGG, Yb:YAG, and Yb-doped tungstates lasers using Cr 4+ -doped garnets

    NASA Astrophysics Data System (ADS)

    Kalisky, Y.; Kalisky, O.; Rachum, U.; Boulon, G.; Brenier, A.

    2006-02-01

    We investigated the CW free-running and repetitive modulation in the kHz frequency domain of a passively Q-switched, diode-pumped Yb:YAG, Yb:GGG and Yb:KYW lasers, by using Cr 4+:YAG as a saturable absorber. The results presented here are focused towards the design of a passively Q-switched Yb doped garnets or Yb doped tungstates microlaser. The free-running performance of Yb:YAG, Yb:GGG, Yb:KGW and Yb:KYW were characterized, and experimental parameters such as gain and loss were evaluated. We carried out a fit between our experimental results and an existing numerical model, which relates the experimental and the physical parameters of the ytterbium diode-pumped system to the minimal threshold pumping power. The best performance among the laser crystals was obtained for Yb:YAG laser. A maximum peak power of ~4.5-kW, at an average output power of 1.32-W, were extracted with of ~25 % extraction efficiency.

  2. Experimental study of supercontinuum generation in an amplifier based on an Yb3+ doped nonlinear photonic crystal fiber

    NASA Astrophysics Data System (ADS)

    Baselt, Tobias; Taudt, Christopher; Nelsen, Bryan; Lasagni, Andrés. Fabián.; Hartmann, Peter

    2016-03-01

    The use of supercontinuum light sources in different optical measurement methods, like microscopy or optical coherence tomography, has increased significantly compared to classical wideband light sources. The development of various optical measurement techniques benefits from the high brightness and bandwidth, as well as the spatial coherence of these sources. For some applications, only a portion of the broad spectral range can be used. Therefore, an increase of the spectral power density in limited spectral regions would provide a clear advantage over spectral filtering. This study describes a method to increase the spectral power density of supercontinuum sources by amplifying the excitation wavelength inside a nonlinear photonic crystal fiber (PCF). An ytterbium doped photonic crystal fiber was manufactured by a sol-gel process and used in a fiber amplifier setup as the nonlinear fiber medium. In order to characterize the fiber's optimum operational characteristics, group-velocity dispersion (GVD) measurements were performed on the fiber during the amplification process. For this purpose, a notch-pass mirror was used to launch the radiation of a stabilized laser diode at 976 nm into the fiber sample for pumping. The performance of the fiber was compared with a conventional PCF. Finally, the system as a whole was characterized in reference to common solid state-laser-based photonic supercontinuum light sources. An improvement of the power density up to 7.2 times was observed between 1100 nm to 1380 nm wavelengths.

  3. Crystal Structures and Low Temperature Cofiring Ceramic Property of (1-x)(Li, RE)W2O8-xBaWO4 Ceramics (RE=Y, Yb)

    NASA Astrophysics Data System (ADS)

    Kim, Jeong Seog; Lee, Jong Cheol; Cheon, Chae Il; Kang, Hyun-Ju

    2006-09-01

    The crystal structures and low temperature cofiring ceramic (LTCC) microwave dielectric properties of ABW2O8 (A=Li, Na, Zn, B=Y, Yb, Mn, Fe) and the (1-x)LiYW2O8-xBaWO4 binary system have been characterized. LiYW2O8 has a new type of crystal structure in-between the wolframite (MgWO4) and scheelite (BaWO4) structures: the space group P2 and the lattice parameters of a=9.9815(5), b=5.7913(3), c=5.0058(2) Å, and β=94.2158(2)°. The new materials LiREW2O8 (RE=Y, Yb) have highly positive τf values (+63.8 ppm/°C for RE=Y) in contrast to the negative τf values of BaWO4 and MgWO4. τf can be tailored to near zero by combining LiYW2O8 and BaWO4. The effects of sinter-additives on τf, Q f0 (GHz), and sintering temperature have been also characterized. The crystal structure has been analyzed by the Rietveld refinement method using neutron diffraction data.

  4. Lasing in a Tm:Ho:Yb{sub 3}Al{sub 5}O{sub 12} crystal pumped into the {sup 3}H{sub 6} – {sup 3}F{sub 4} transition

    SciTech Connect

    Zavartsev, Yu D; Zagumennyi, A I; Kalachev, Yu L; Kutovoi, S A; Mikhailov, V A; Shcherbakov, I A

    2016-03-31

    A growth technology has been developed, and a Tm:Ho:Yb{sub 3}Al{sub 5}O{sub 12} laser crystal of high optical quality has been grown by Czochralski method. Its spectral and luminescent characteristics are studied. Lasing at a wavelength of 2100 nm is obtained under pumping into the absorption line on the {sup 3}H{sub 6} – {sup 3}F{sub 4} transition of the Tm{sup 3+} ion at a wavelength of 1678 nm. The slope and total (optical) efficiencies of the laser at an output power of up to 320 mW reach 41% and 30%, respectively. (lasers)

  5. Field-dependent Collective ESR Mode in YbRh2Si2

    SciTech Connect

    Petrovic, C.; Holanda, L.M.; Duque, J.G.S.; Bittar, E.M.; Adriano, C.; Pagliuso, P.G.; Rettori, C.; Hub, R.W.; Maquilon, S.; Fisk, Z.; Huber, D.L.; Oseroff, S.B.

    2009-10-15

    Electron spin resonance (ESR) experiments in YbRh{sub 2}Si{sub 2} Kondo lattice (T{sub K} {approx_equal} 25 K) at different field/frequencies (4.1 {le} v {le} 34.4 GHz) and H{sub {perpendicular}c} revealed: (i) a strong field dependent Yb{sup 3+} spin-lattice relaxation, (ii) a weak field and T-dependent effectiveg-value, (iii) a suppression of the ESR intensity beyond 15% of Lu-doping, and (iv) a strong sample and Lu-doping ({le}15%) dependence of the ESR data. These results suggest that the ESR signal in YbRh{sub 2}Si{sub 2} may be due to a coupled Yb{sup 3+}-conduction electron resonant collective mode with a subtle field-dependent spins dynamic.

  6. Intense near-infrared emission from ZnO-LiYbO(2) hybrid phosphors through efficient energy transfer from ZnO to Yb(3+).

    PubMed

    Ye, Song; Jiang, Nan; He, Feng; Liu, Xiaofeng; Zhu, Bin; Teng, Yu; Qiu, Jian Rong

    2010-01-18

    The ZnO-LiYbO(2) hybrid phosphors were sintered by the solid-state reaction method, in which the intense near-infrared emission around 1000 nm due to Yb(3+ 2)F(5/2)-->(2)F(7/2) transition was obtained due to the efficient energy transfer from ZnO to Yb(3+) ions. The growth of the LiYbO(2) crystal and the formation of the diffusion layer between LiYbO(2) and ZnO were confirmed by XRD, SEM and EDX studies. The high efficient energy transfer is benefited from the inter-diffusion of Li(+), Yb(3+) and Zn(2+) in the diffusion region. The spectroscopy results clearly indicated that the ZnO-LiYbO(2) hybrid phosphors can harvest the energy from near-UV photons in a broad wavelength region and effectively convert them into Yb(3+) near-infrared emission.

  7. Heteroepitaxy of single-crystal LaLuO{sub 3} on GaAs(111)A by atomic layer deposition

    SciTech Connect

    Liu Yiqun; Heo, Jaeyeong; Gordon, Roy G.; Xu Min; Ye, Peide D.

    2010-10-18

    We demonstrate that LaLuO{sub 3} films can be grown epitaxially on sulfur-passivated GaAs(111)A substrates by atomic layer deposition (ALD). Transmission electron microscopy and x-ray diffraction analyses reveal that the oxide film exhibits a cubic structure with a lattice mismatch of -3.8% relative to GaAs. The epitaxial layer has a high degree of crystalline perfection and is relaxed. Electrical characterizations performed on this structure show interfaces with a low interface state density of {approx}7x10{sup 11} cm{sup -2} eV{sup -1}. The measured dielectric constant is around 30, which is close to its bulk crystalline value. In contrast, ALD LaLuO{sub 3} is polycrystalline on GaAs(100) and amorphous on Si(111).

  8. Crystal structure, magnetic and dielectric behavior of h-LuMnxO3±δ ceramics (0.95≤x≤1.04)

    NASA Astrophysics Data System (ADS)

    Baghizadeh, A.; Vieira, J. M.; Amaral, J. S.; Graça, M. P.; Soares, M. R.; Mota, D. A.; Amaral, V. S.

    2015-12-01

    Lattice constants, magnetic properties and dielectric behavior of h-LuMnxO3±δ solid solution (0.95≤x≤1.04) of bulk ceramic samples prepared by the solid state reaction method were studied to determine the role of stoichiometry changes on the crystalline structure and magneto-electric coupling. It is found that increasing of Mn content results in reduction of cell volume of h-LuMnxO3±δ ceramics mostly due to shrinkage of a-axis length. The antiferromagnetic interactions of Mn3+ ions weaken with cell volume contraction. A weak ferromagnetic contribution appeared in all samples and extends up to the Neel temperature, TN. Irreversibility in temperature dependent magnetic measurements already reported for stoichiometric compositions of hexagonal RMnO3 oxides appears for all h-LuMnxO3±δ samples right below Neel ordering transition. An increase of magnetic coercive field and magnetization on cooling below TN in samples is observed in field dependent magnetization and rises as x increases. In addition to the antiferromagnetic ordering transition at TN, two anomalies of the temperature dependent magnetic susceptibility and dielectric constant are identified below TN, centered at 69 K and 31 K respectively, being probably due to inhomogeneity of the crystalline structure inside ceramic grains. Changes of the dielectric constant at TN can be attributed to magneto-electric coupling in the off-stoichiometric hexagonal LuMnxO3±δ lattice. The behavior of the dielectric relaxation follows a thermally activated mechanism with activation energy values characteristic of polaron hoping.

  9. Analysis of vacuum ultraviolet electronic spectra of Ce3+ and Pr3+ ions in Ca9Lu(PO4)7: crystal-field calculations and simulation of optical spectra

    NASA Astrophysics Data System (ADS)

    Ma, C.-G.; Trevisani, M.; Piccinelli, F.; Ivanovskikh, K. V.; Bettinelli, M.; Brik, M. G.

    2013-04-01

    The 4f-5d excitation and emission spectra of Ce3+ and Pr3+ ions in Ca9Lu(PO4)7 as recently reported (2012 J. Phys.: Condens. Matter 24 385502) were further analyzed and simulated by employing the effective Hamiltonian model for the 4fN and 4fN-15d electronic configurations of impurity lanthanide ions and the exchange charge model of crystal-field theory. The multi-site effect on the 4f-5d transition spectra was explicitly discussed from the points of view of the local structure and site occupation ratios of lanthanide ions in Ca9Lu(PO4)7. An excellent agreement between the predicted and measured spectra confirms the validity of the performed calculations. Based on these energy level and intensity calculation results, the radiative lifetimes of the 5d-4f emissions of Ce3+ and Pr3+ ions have been modeled to show nearly independent temperature trends. Comparison with the measured lifetimes suggests the nonradiative relaxation process in this host is probably related to the intrinsic defect states. In addition to the studies of the 4f-5d transitions, a general theoretical scheme to calculate the lowest 4f-6s transition energy of the Ce3+ ion was proposed for the first time on the basis of the ligand polarization model. The predicted 6s energy position of the Ce3+ ion in Ca9Lu(PO4)7 is solid evidence corroborating our previous spectroscopic assignment.

  10. Analysis of vacuum ultraviolet electronic spectra of Ce3+ and Pr3+ ions in Ca9Lu(PO4)7: crystal-field calculations and simulation of optical spectra.

    PubMed

    Ma, C-G; Trevisani, M; Piccinelli, F; Ivanovskikh, K V; Bettinelli, M; Brik, M G

    2013-04-24

    The 4f-5d excitation and emission spectra of Ce(3+) and Pr(3+) ions in Ca9Lu(PO4)7 as recently reported (2012 J. Phys.: Condens. Matter 24 385502) were further analyzed and simulated by employing the effective Hamiltonian model for the 4f(N) and 4f(N-1)5d electronic configurations of impurity lanthanide ions and the exchange charge model of crystal-field theory. The multi-site effect on the 4f-5d transition spectra was explicitly discussed from the points of view of the local structure and site occupation ratios of lanthanide ions in Ca9Lu(PO4)7. An excellent agreement between the predicted and measured spectra confirms the validity of the performed calculations. Based on these energy level and intensity calculation results, the radiative lifetimes of the 5d-4f emissions of Ce(3+) and Pr(3+) ions have been modeled to show nearly independent temperature trends. Comparison with the measured lifetimes suggests the nonradiative relaxation process in this host is probably related to the intrinsic defect states. In addition to the studies of the 4f-5d transitions, a general theoretical scheme to calculate the lowest 4f-6s transition energy of the Ce(3+) ion was proposed for the first time on the basis of the ligand polarization model. The predicted 6s energy position of the Ce(3+) ion in Ca9Lu(PO4)7 is solid evidence corroborating our previous spectroscopic assignment.

  11. Diode-pumped Kerr-lens mode-locked Yb:LYSO laser with 61fs pulse duration.

    PubMed

    Tian, Wenlong; Wang, Zhaohua; Wei, Long; Peng, Yingnan; Zhang, Jinwei; Zhu, Zheng; Zhu, Jiangfeng; Han, Hainian; Jia, Yulei; Zheng, Lihe; Xu, Jun; Wei, Zhiyi

    2014-08-11

    A stable diode pumped Kerr-lens mode-locked (KLM) Yb:LuYSiO5 (Yb:LYSO) laser of generating 61 fs pulses at a central wavelength of 1055.4 nm is experimentally demonstrated. This is, to the best of our knowledge, the first demonstration of femtosecond KLM operation in Yb:LYSO laser, and it is believed that 61 fs is the shortest pulse duration ever produced from an Yb-doped orthosilicate laser. The average output power of the mode-locked laser is 40 mW and the repetition rate is 113 MHz.

  12. Structural and Crystal Chemical Properties of Alkali Rare-earth Double Phosphates

    DOE PAGES

    Farmer, James Matthew; Boatner, Lynn A.; Chakoumakos, Bryan C.; ...

    2016-01-01

    When appropriately activated, alkali rare-earth double phosphates of the form: M3RE(PO4)2 (where M denotes an alkali metal and RE represents either a rare-earth element or Y or Sc) are of interest for use as inorganic scintillators for radiation detection at relatively long optical emission wavelengths. These compounds exhibit layered crystal structures whose symmetry properties depend on the relative sizes of the rare-earth and alkali-metal cations. Single-crystal X-ray and powder neutron diffraction methods were used here to refine the structures of the series of rare-earth double phosphate compounds: K3RE(PO4)2 with RE = Lu, Er, Ho, Dy, Gd, Nd, Ce, plus Ymore » and Sc - as well as the compounds: A3Lu(PO4)2, with A = Rb, and Cs. The double phosphate K3Lu(PO4)2 was reported and structurally refined previously. This material had a hexagonal unit cell at room temperature with the Lu ion six-fold coordinated with oxygen atoms of the surrounding phosphate groups. Additionally two lower-temperature phases were observed for K3Lu(PO4)2. The first phase transition to a monoclinic P21/m phase occurred at ~230 K, and the Lu ion retained its six-fold coordination. The second K3Lu(PO4)2 phase transition occurred at ~130 K. The P21/m space group symmetry was retained, however, one of the phosphate groups rotated to increase the oxygen coordination number of Lu from six to seven. This structure then became isostructural with the room-temperature form of the compound K3Yb(PO4)2 reported here that also exhibits an additional high-temperature phase which occurs at T = 120 °C with a transformation to hexagonal P-3 space group symmetry and a Yb-ion coordination number reduction from seven to six. This latter result was confirmed using EXAFS. The single-crystal growth methods structural systematics, and thermal expansion properties of the present series of alkali rare-earth double phosphates, as determined by X-ray and neutron diffraction methods, are treated here.« less

  13. Structural and Crystal Chemical Properties of Alkali Rare-earth Double Phosphates

    SciTech Connect

    Farmer, James Matthew; Boatner, Lynn A.; Chakoumakos, Bryan C.; Rawn, Claudia J.; Richardson, Jim

    2016-01-01

    When appropriately activated, alkali rare-earth double phosphates of the form: M3RE(PO4)2 (where M denotes an alkali metal and RE represents either a rare-earth element or Y or Sc) are of interest for use as inorganic scintillators for radiation detection at relatively long optical emission wavelengths. These compounds exhibit layered crystal structures whose symmetry properties depend on the relative sizes of the rare-earth and alkali-metal cations. Single-crystal X-ray and powder neutron diffraction methods were used here to refine the structures of the series of rare-earth double phosphate compounds: K3RE(PO4)2 with RE = Lu, Er, Ho, Dy, Gd, Nd, Ce, plus Y and Sc - as well as the compounds: A3Lu(PO4)2, with A = Rb, and Cs. The double phosphate K3Lu(PO4)2 was reported and structurally refined previously. This material had a hexagonal unit cell at room temperature with the Lu ion six-fold coordinated with oxygen atoms of the surrounding phosphate groups. Additionally two lower-temperature phases were observed for K3Lu(PO4)2. The first phase transition to a monoclinic P21/m phase occurred at ~230 K, and the Lu ion retained its six-fold coordination. The second K3Lu(PO4)2 phase transition occurred at ~130 K. The P21/m space group symmetry was retained, however, one of the phosphate groups rotated to increase the oxygen coordination number of Lu from six to seven. This structure then became isostructural with the room-temperature form of the compound K3Yb(PO4)2 reported here that also exhibits an additional high-temperature phase which occurs at T = 120 °C with a transformation to hexagonal P-3 space group symmetry and a Yb-ion coordination number reduction from seven to six. This latter result was confirmed using EXAFS. The single-crystal

  14. Luminescence properties of Er3+/Nd3+ co-doped Na5Lu9F32 single crystals for 2.7 μm mid-infrared laser

    NASA Astrophysics Data System (ADS)

    Tang, Qingyang; Xia, Haiping; Sheng, Qiguo; He, Shinan; Zhang, Jianli; Chen, Baojiu

    2017-10-01

    The enhanced 2.7 μm mid-infrared emission from the Er3+:4I11/2 → 4I13/2 transition with Nd3+ ions as the sensitizer was achieved in the Na5Lu9F32 single crystal which was successfully grown by a Bridgman method. The transmission spectrum was tested and almost no absorption of 2.7 μm band was observed. It was indicated that the content of OH- ion was very low in the crystal and it was beneficial to the 2.7 μm mid-infrared laser output. Intense 2.7 μm emissions were achieved with Nd3+ ions sensitizing Er3+ ions under the 800 nm LD pumping and the energy transfer processes between Er3+ and Nd3+ ions were analyzed. Meanwhile, the greatly decreased near infrared emission at 1.5 μm and green up-conversion emission were obtained. Additionally, the optimized concentration ratio of Er3+ to Nd3+ for efficient 2.7 μm emission was investigated in this work and the maximum emission cross section at 2.7 μm was calculated. The decay curve of 1.5 μm emission could be well fitted by Inokuti-Hirayama expression, which was strongly indicated the dipole-dipole energy transfer from Er3+ to Nd3+ ions. The results showed that Er3+/Nd3+ co-doped Na5Lu9F32 single crystal had potential applications in 2.7 μm mid-infrared laser.

  15. Site symmetry and crystal field splittings of Ce3+ in LiLuF4 and LiSr0.8Ca0.2AlF6

    NASA Astrophysics Data System (ADS)

    Yamaga, M.; Inoue, T.; Yabashi, S.; Honda, M.; Wells, J. P. R.; Shimamura, K.; Fukuda, T.

    Electron paramagnetic resonance (EPR) spectra of Ce3+ in LiLuF 4 (LLF) and LiSr0.8Ca0.2AlF6 (LSCAF) observed at low temperatures (<20 K) show that the Ce3+ centers have tetragonal and pseudo-trigonal symmetry with (g(parallel to) , g(perpendicular to) )=(2.751, 1.467) and (2.14, 0.80), respectively. The EPR lines of Ce3+ in LSCAF are inhomogeneously broadened by different Ce3+ configurations which correspond to the random occupation of the second nearest neighbor cation sites by Ca2+ and Sr2+ and/or charge compensators. These EPR results indicate that the Ce3+ centers in LLF and LSCAF are associated with substitution of Ce3+ for Lu3+ with eight-fold coordination and Sr2+/Ca2+ with six-fold coordination, respectively. Fourier transform infrared absorption has been used to measure transitions between the F-2(5/2) ground state and the F-2(7/2) multiplet of Ce3+ in LLF at 10 K. The optical absorption and luminescence of Ce3+ :LLF and Ce3+ :LSCAF in the UV range are strongly polarized. The energy levels and polarization dependence of the optical transitions can be accounted for in terms of the crystal field potential experienced by the Ce3+ ions under the action of the different point group symmetries.

  16. Impurity-trapped excitons and electron traps in CaF2:Yb2+ and SrF2:Yb2+ probed by transient photoluminescence enhancement

    NASA Astrophysics Data System (ADS)

    Senanayake, P. S.; Wells, J. P. R.; Reid, M. F.; Berden, G.; Meijerink, A.; Reeves, R. J.

    2013-01-01

    CaF$_2$:Yb$^{2+}$ and SrF$_2$:Yb$^{2+}$ crystals have been investigated by a two-color UV + IR transient photoluminescence enhancement technique. The enhancement gives information about both changes in internal energy levels of the excitons and liberation of electrons from traps in the crystals.

  17. EPR investigations of Fe/sup 3 +/ in single crystals and powders of the zircon-structure orthophosphates LuPO/sub 4/, YPO/sub 4/, and ScPO/sub 4/

    SciTech Connect

    Rappaz, M.; Ramey, J.O.; Boatner, L.A.; Abraham, M.M.

    1982-01-01

    Iron-doped single crystals of the zircon-structure orthophosphates LuPO/sub 4/, YPO/sub 4/, and ScPO/sub 4/ have been grown by means of a flux technique. Corresponding powders have been prepared independently by a urea precipitation technique and electron paramagnetic resonance measurements demonstrate that the Fe/sup 3 +/ impurity is situated in the same substitutional site in both the single crystals and the powders for all three hosts. The sign of the crystal field parameter b/sup 0//sub 2/ is shown to be positive (opposite to that found for Gd/sup 3 +/ in these hosts). The crystal-field splittings were found to be largest for the scandium host and smallest for the yttrium host. The EPR results show that iron can be incorporated in a substitutional crystallographic site in material prepared by either a high temperature process or by a low temperature precipitation and calcination (approx.800 /sup 0/C), and these findings have implications for the use of lanthanide and related orthophosphates as a host material for the isolation of nuclear wastes.

  18. Structure and properties of Pb(Lu{sub 1/2}Nb{sub 1/2})O{sub 3}–0.2PbTiO{sub 3} relaxor ferroelectric crystal

    SciTech Connect

    Liu, Ying; Yang, Xiaoming; Lai, Fachun; Huang, Zhigao; Li, Xiuzhi; Wang, Zujian; He, Chao; Lin, Ju; Long, Xifa

    2015-07-15

    Graphical abstract: The relaxor state of the crystal was demonstrated by the dielectric behavior. - Highlights: • PLN–0.2PT ferroelectric crystal was obtained by the TSSG technique. • The super-lattice reflections were identified by XRD and TEM results. • The PLN–0.2PT crystal is a typical relaxor ferroelectric. - Abstract: Ferroelectric crystal Pb(Lu{sub 1/2}Nb{sub 1/2})O{sub 3}–0.2PbTiO{sub 3} (PLN–0.2PT) was successfully obtained by a top-seed solution growth technique. At room temperature the symmetry was orthorhomic according to X-ray diffraction (XRD). The super-lattice reflections were identified by XRD and transmission electron microscope (TEM). The micro-domain structure was detected by TEM. The temperature dependence of the dielectric constant (ϵ′) shows a typical relaxor behavior. The temperature dependence of coercive electric field and remnant polarizations were investigated, which also shows the relaxor feature.

  19. An investigation of structural parameters and magnetic and optical properties of EuLn{sub 2}Q{sub 4} (Ln=Tb-Lu, Q=S, Se)

    SciTech Connect

    Jin Gengbang; Choi, Eun Sang; Guertin, Robert P.; Albrecht-Schmitt, Thomas E.

    2008-01-15

    EuLn{sub 2}Q{sub 4} (Ln=Tb-Lu; Q=S, Se) has been synthesized using Sb{sub 2}Q{sub 3} (Q=S, Se) fluxes at 1000 deg. C. These compounds crystallize in a CaFe{sub 2}O{sub 4}-type three-dimensional channel structure that is built from edge-shared double rutile chains of [LnQ{sub 6}] octahedra running down the b-axis. Each double chain is connected at the vertices to four other double chains to form open channels where bicapped trigonal prismatic Eu{sup 2+} ions reside. All of these compounds show antiferromagnetic ordering with Neel temperatures, T{sub N}{approx}3-4 K. The optical band gaps for EuTb{sub 2}Se{sub 4}, EuDy{sub 2}Se{sub 4}, EuHo{sub 2}Se{sub 4}, EuEr{sub 2}Se{sub 4}, EuTm{sub 2}Se{sub 4}, EuYb{sub 2}Se{sub 4} EuLu{sub 2}Se{sub 4}, and EuYb{sub 2}S{sub 4} are found to be 2.0, 1.8, 1.8, 1.7, 1.8, 1.3, 1.7, and 1.6 eV, respectively. - Graphical abstract: A view of the three-dimensional channel structure of EuYb{sub 2}S{sub 4} down the b-axis.

  20. Radiolysis of LaF3 crystals with rare-earth impurities

    NASA Astrophysics Data System (ADS)

    Radzhabov, E. A.

    2016-10-01

    The absorption spectra of LaF3 crystals, both pure and doped with rare-earth fluorides (YF3, CeF3, NdF3, PrF3, SmF3, EuF3, GdF3, TbF3, DyF3, HoF3, ErF3, TmF3, YbF3, and LuF3) have been investigated. All these impurities can be separated into two groups with respect to the shape of the absorption spectra of irradiated crystals. The spectra of the crystals doped with Nd, Sm, Tm, and Yb exhibit, along with 200-nm hole band F 3 - , weak bands due to RE2+-anion vacancy centers. The spectra of LaF3 crystals with Y, Ce, Pr, Gd, Tb, Dy, Ho, Er, and Lu impurities exhibit, along with the hole-center bands (F 3 - at 200 nm and VkA at 320 nm), bands of comparable intensity, which can be attributed to RE3+- F centers. This conclusion is confirmed by preliminary quantum-chemical calculations and the estimation of the levels location in the energy-band diagram.

  1. Continuous-wave and Q-switched laser performance of Nd:Lu0.99La0.01VO4 mixed crystals at 1.06 μm

    NASA Astrophysics Data System (ADS)

    Huang, Guoxi; Zhao, Bin; Yu, Yongqin; Du, Chenlin; Guo, Yayin; Ruan, Shuangchen; Chen, Jianzhong

    2012-11-01

    We report continuous-wave (CW) and actively Q-switched laser performance achieved with an uncoated mixed laser crystal Nd:Lu0.99La0.01VO4 at 1065.655 nm end-pumped by a laser-diode-array. The maximum CW output power of 6.26 W was obtained with the optical conversion efficiency of 31.3%. For the Q-switching operation, a maximum average output power of 6.06 W was obtained at the pulse repetition frequency (PRF) of 90 kHz, yielding an optical conversion efficiency of 30.3%. The highest pulse energy and highest peak power obtained were 954 μJ and 63.8 kW at the PRF of 5 kHz, respectively.

  2. Single crystal synthesis and magnetism of the BaLn2O4 family (Ln = lanthanide)

    DOE PAGES

    Besara, Tiglet; Lundberg, Matthew S.; Sun, Jifeng; ...

    2014-05-27

    The series of compounds in the BaLn2O4 family (Ln = La–Lu, Y) has been synthesized for the first time in single crystalline form, using a molten metal flux. The series crystallizes in the CaV2O4 structure type with primitive orthorhombic symmetry (space group Pnma, #62), and a complete structural study of atomic positions, bonds, angles, and distortions across the lanthanide series is presented. With the exception of the Y, La, Eu, and Lu members, magnetic susceptibility measurements were performed between 2 K and 300 K. BaCe2O4 and BaYb2O4 display large crystal fields effects and suppression of magnetic ordering. As a result,more » all compounds show signs of magnetic frustration due to the trigonal arrangements of the trivalent lanthanide cations in the structure.« less

  3. Structure induced Yb valence changes in the solid solution Yb(x)Ca(1-x)C2.

    PubMed

    Link, Pascal; Glatzel, Pieter; Kvashnina, Kristina; Trots, Dmytro M; Smith, Ronald I; Ruschewitz, Uwe

    2013-06-17

    The solid solution Yb(x)Ca(1-x)C2 (0 ≤ x ≤ 1) was synthesized by reaction of the elements at 1323 K. The crystal structures within this solid solution, as elucidated from synchrotron powder diffraction data, depend on x and exhibit some interesting features that point to a structure dependent valence state of Yb. Compounds with x ≥ 0.75 crystallize in the tetragonal CaC2 type structure (I4/mmm, Z = 2) and obey Vegard's law; for x ≤ 0.75 the monoclinic ThC2 type structure (C2/c, Z = 4) is found, which coexists with the monoclinic CaC2-III type structure (C2/m, Z = 4) for x ≤ 0.25. The monoclinic modifications show a strong deviation from Vegard's law. Their unit cell volumes are remarkably larger than expected for a typical Vegard system. HERFD-XANES spectroscopic investigations reveal that different Yb valence states are responsible for the observed volume anomalies. While all tetragonal compounds contain mixed-valent Yb with ∼75% Yb(3+) (similar to pure YbC2), all monoclinic modifications contain exclusively Yb(2+). Therefore, Yb(x)Ca(1-x)C2 is a very rare example of a Yb containing compound showing a strong structure dependence of the Yb valence state. Moreover, temperature dependent synchrotron powder diffraction, neutron TOF powder diffraction, and HERFD-XANES spectroscopy experiments reveal significant Yb valence changes in some compounds of the Yb(x)Ca(1-x)C2 series that are induced by temperature dependent phase transitions. Transitions from the tetragonal CaC2 type structure to the monoclinic ThC2 or the cubic CaC2-IV type structure (Fm3m, Z = 4) are accompanied by drastic changes of the mean Yb valence from ∼2.70 to 2.0 in compounds with x = 0.75 and x = 0.91. Finally, the determination of lattice strain arising inside the modifications with ordered dumbbells (ThC2 and CaC2 type structures) by DSC measurements corroborated our results concerning the close relationship between crystal structure and Yb valence in the solid solution Yb(x)Ca(1-x

  4. Hydrogen in polar intermetallics: Syntheses and structures of the ternary Ca{sub 5}Bi{sub 3}D{sub 0.93}, Yb{sub 5}Bi{sub 3}H{sub x}, and Sm{sub 5}Bi{sub 3}H{sub a}pprox{sub 1} by powder neutron or single crystal X-ray diffraction

    SciTech Connect

    Alejandro Leon-Escamilla, E.; Dervenagas, Panagiotis; Stassis, Constantine; Corbett, John D.

    2010-01-15

    The syntheses of the title compounds are described in detail. Structural characterizations from refinements of single crystal X-ray diffraction data for Yb{sub 5}Bi{sub 3}H{sub x} and Sm{sub 5}Bi{sub 3}H{sub a}pprox{sub 1} and of powder neutron diffraction data for Ca{sub 5}Bi{sub 3}D{sub 0.93(3)} are reported. These confirm that all three crystallize with the heavy atom structure type of beta-Yb{sub 5}Sb{sub 3}, and the third gives the first proof that the deuterium lies in the center of nominal calcium tetrahedra, isostructural with the Ca{sub 5}Sb{sub 3}F-type structure. These Ca and Yb phases are particularly stable with respect to dissociation to Mn{sub 5}Si{sub 3}-type product plus H{sub 2}. Some contradictions in the literature regarding Yb{sub 5}Sb{sub 3} and Yb{sub 5}Sb{sub 3}H{sub x} phases are considered in terms of adventitious hydrogen impurities that are generated during reactions in fused silica containers at elevated temperatures. - Graphical abstract: The structure of Ca{sub 5}Bi{sub 3}H{sub 0.93} occurs in the novel Ca{sub 5}Sb{sub 3}F structure type with D centered in the shaded calcium tetrahedra.

  5. Sub-10 nm lanthanide doped BaLuF{sub 5} nanocrystals: Shape controllable synthesis, tunable multicolor emission and enhanced near-infrared upconversion luminescence

    SciTech Connect

    Rao, Ling; Lu, Wei; Wang, Haibo; Yi, Zhigao; Zeng, Songjun; Li, Zheng

    2015-04-15

    Highlights: • Sub-10 nm cubic phase BaLuF{sub 5} nanocrystals were synthesized by a hydrothermal method for the first time. • Tunable multicolor from yellow to yellow-green was achieved by controlling Gd{sup 3+} content in BaLuF{sub 5}:Yb/Er system. • Intense near-infrared upconversion luminescence in BaLuF{sub 5}:Gd/Yb/Tm nanocrystal. • The enhancement near-infrared luminescence can be realized by adjusting the content of Gd{sup 3+} in BaLuF{sub 5}:Gd/Yb/Tm system. - Abstract: In this study, sub-10 nm BaLuF{sub 5} nanocrystals with cubic phase structure were synthesized by a solvothermal method using oleic acid as the stabilizing agent. The as-prepared BaLuF{sub 5} nanocrystals were characterized by transmission electron microscopy (TEM), X-ray diffraction (XRD), and analyzed by the upconversion (UC) spectra. The TEM results reveal that these samples present high uniformity. Compared with Gd-free samples, the size of BaLuF{sub 5}:Yb/Er doped with 10% Gd{sup 3+} decreased to 5.6 nm. In addition, BaLuF{sub 5}:Yb/Tm/Gd upconversion nanoparticles (UCNPs) presented efficient near-infrared (NIR)-NIR UC luminescence. Therefore, it is expected that these ultra-small BaLuF{sub 5} nanocrystals with well-controlled shape, size, and UC emission have potential applications in biomedical imaging fields.

  6. Electronic structure and direct observation of ferrimagnetism in multiferroic hexagonal YbFeO3

    DOE PAGES

    Cao, Shi; Sinha, Kishan; Zhang, Xin; ...

    2017-06-26

    Here, the magnetic interactions between rare-earth and Fe ions in hexagonal rare-earth ferrites (h–RFeO3), may amplify the weak ferromagnetic moment on Fe, making these materials more appealing as multiferroics. To elucidate the interaction strength between the rare-earth and Fe ions as well as the magnetic moment of the rare-earth ions, element-specific magnetic characterization is needed. Using x-ray magnetic circular dichroism, we have studied the ferrimagnetism in h–YbFeO3 by measuring the magnetization of Fe and Yb separately. The results directly show antialignment of magnetization of Yb and Fe ions in h–YbFeO3 at low temperature, with an exchange field on Yb ofmore » about 17 kOe. The magnetic moment of Yb is about 1.6μB at low temperature, significantly reduced compared with the 4.5μB moment of a free Yb3+. In addition, the saturation magnetization of Fe in h–YbFeO3 has a sizable enhancement compared with that in h–LuFeO3. These findings directly demonstrate that ferrimagnetic order exists in h–YbFeO3; they also account for the enhancement of magnetization and the reduction of coercivity in h–YbFeO3 compared with those in h–LuFeO3 at low temperature, suggesting an important role for the rare-earth ions in tuning the multiferroic properties of h–RFeO3.« less

  7. High-efficiency Watt-level picosecond pulse generation based on Yb:Gd3AlxGa5-xO12 crystal

    NASA Astrophysics Data System (ADS)

    Li, Yanbin; Jia, Zhitai; Lou, Fei; Zhang, Baitao; He, Jingliang; Tao, Xutang

    2015-07-01

    A diode-pumped passively mode-locked Yb3+:Gd3Al0.5Ga4.5O12 (Yb:GAGG) laser has been investigated by using a semiconductor saturable absorber mirror (SESAM) for the first time. Pulses with duration of 1.6 ps were produced at the central wavelength of 1027.8 nm. At the absorbed pump power of 8.4 W, the maximum average output power of 1.02 W was obtained with the repetition rate of 45 MHz. The corresponding single pulse energy and the peak power were calculated to be 22.7 nJ and 14.2 kW, respectively.

  8. Eleven new compounds in the RE-Cd-Ge systems (RE=Pr, Nd, Sm, Gd-Yb; Y): Crystal chemistry of the RE{sub 2}CdGe{sub 2} series

    SciTech Connect

    Guo Shengping; Meyers, John J.; Tobash, Paul H.; Bobev, Svilen

    2012-08-15

    A large new family of rare-earth metal-cadmium-germanides RE{sub 2}CdGe{sub 2} (RE=Y, Pr, Nd, Sm, Gd-Yb) has been synthesized and structurally characterized. All eleven structures have been established from single-crystal X-ray diffraction data and have been found to belong to the tetragonal Mo{sub 2}FeB{sub 2} structure type (ordered ternary variant of the U{sub 3}Si{sub 2} structure type-space group P4/mbm (No. 127), Z=2; Pearson symbol tP10). The structural variations among the three series of isostructural RE{sub 2}MgGe{sub 2}, RE{sub 2}InGe{sub 2}, and RE{sub 2}CdGe{sub 2} compounds are discussed, as well as the crystal chemistry changes as a function of the decreasing size of the rare-earth metals (lattice constants a=7.176(2)-7.4589(12) A and c=4.1273(14)-4.4356(13) A). The experimental results have been complemented by tight-binding linear muffin-tin orbital (TB-LMTO) electronic structure calculations. - Graphical abstract: More than 300 compounds have been reported to crystallize with the tetragonal U{sub 3}Si{sub 2} structure type, or the Mo{sub 2}FeB{sub 2} structure type, which is its ordered ternary variant. Among them, there are several large RE{sub 2}CdX{sub 2} classes, where the X-elements are typically late transition metals such as Cu, Ni, Au, Pd, Pt, and Rh. The new RE{sub 2}CdGe{sub 2} phases (RE=Y, Pr, Nd, Sm, Gd-Yb) increase the diversity and represent the first cadmium germanides. Highlights: Black-Right-Pointing-Pointer RE{sub 2}CdGe{sub 2} (RE=Y, Pr, Nd, Sm, Gd-Yb) are new ternary germanides. Black-Right-Pointing-Pointer Their structures can be recognized as a 1:1 intergrowth of CsCl- and AlB{sub 2}-like slabs. Black-Right-Pointing-Pointer The Ge atoms are covalently bound into Ge{sub 2} dumbbells. Black-Right-Pointing-Pointer Almost all RE{sub 2}CdGe{sub 2} phases are the first structurally characterized phases in the respective ternary RE-Cd-Ge systems.

  9. Characterization of 1.2×1.2 mm2 silicon photomultipliers with Ce:LYSO, Ce:GAGG, and Pr:LuAG scintillation crystals as detector modules for positron emission tomography

    NASA Astrophysics Data System (ADS)

    Omidvari, N.; Sharma, R.; Ganka, T. R.; Schneider, F. R.; Paul, S.; Ziegler, S. I.

    2017-04-01

    The design of a positron emission tomography (PET) scanner is specially challenging since it should not compromise high spatial resolution, high sensitivity, high count-rate capability, and good energy and time resolution. The geometrical design of the system alongside the characteristics of the individual PET detector modules contributes to the overall performance of the scanner. The detector performance is mainly influenced by the characteristics of the photo-detector and the scintillation crystal. Although silicon photomultipliers (SiPMs) have already proven to be promising photo-detectors for PET, their performance is highly influenced by micro-cell structure and production technology. Therefore, five types of SiPMs produced by KETEK with an active area size of 1.2 × 1.2 mm2 were characterized in this study. The SiPMs differed in the production technology and had micro-cell sizes of 25, 50, 75, and 100 μm. Performance of the SiPMs was evaluated in terms of their breakdown voltage, temperature sensitivity, dark count rate, and correlated noise probability. Subsequently, energy resolution and coincidence time resolution (CTR) of the SiPMs were measured with five types of crystals, including two Ce:LYSO, two Ce:GAGG, and one Pr:LuAG. Two crystals with a geometry of 1.5 × 1.5 × 6 mm3 were available from each type. The best CTR achieved was ~ 240 ps, which was obtained with the Ce:LYSO crystals coupled to the 50 μm SiPM produced with the trench technology. The best energy resolution for the 511 keV photo-peak was ~ 11% and was obtained with the same SiPM coupled to the Ce:GAGG crystals.

  10. Hydrothermal synthesis, growth mechanism and down-shifting/upconversion photoluminescence of single crystal NaGd(MoO4)2 nanocubes doped with Eu3+, Tb3+ and Yb3+/Er3+

    NASA Astrophysics Data System (ADS)

    Li, Anming; Lin, Hao; Xu, Dekang; Yang, Shenghong; Shao, Yuanzhi; Zhang, Yueli

    2017-06-01

    Uniform and well-crystallized tetragonal NaGd(MoO4)2 nanocrystals with the morphology of nanocubes were synthesized via a modified hydrothermal synthesis method with oleic acid as complexing agent. The as-synthesized NaGd(MoO4)2 nanocubes were characterized by means of powder X-ray diffraction, scanning electron microscopy, transmission electron microscopy and selected area electron diffraction respectively. The side-length of the NaGd(MoO4)2 nanocubes is about 100-150 nm. The SAED pattern indicates highly crystalline nature of the NaGd(MoO4)2 nanocubes. The effect of Na2MoO4 contents on the formation of NaGd(MoO4)2 nanocrystals is investigated. A possible growth mechanism of NaGd(MoO4)2 nanocubes is deduced based on time-dependent morphology evolution and XRD analysis. Down-shifting/upconversion photoluminescence properties of NaGd(MoO4)2: Eu3+, Tb3+ and Yb3+/Er3+ nanocubes are investigated in detail. Furthermore, the energy transfer mechanism for upconversion luminescence in NaGd(MoO4)2: Yb3+/Er3+ nanocubes is investigated on the basis of energy level scheme and the excitation power dependence of upconversion luminescence intensities.

  11. Phase separation in LuFeO{sub 3} films

    SciTech Connect

    Cao, Shi E-mail: caoshi86@gmail.com; Sinha, Kishan; Dowben, Peter A.; Xu, Xiaoshan E-mail: caoshi86@gmail.com; Zhang, Xiaozhe; Wang, Wenbin; Wang, Jian

    2016-05-16

    The structural transition at about 1000 °C, from the hexagonal to the orthorhombic phase of LuFeO{sub 3}, has been investigated in thin films of LuFeO{sub 3}. Separation of the two structural phases of LuFeO{sub 3} occurs on a length scale of micrometer, as visualized in real space using X-ray photoemission electron microscopy. The results are consistent with X-ray diffraction and atomic force microscopy obtained from LuFeO{sub 3} thin films undergoing the irreversible structural transition from the hexagonal to the orthorhombic phase of LuFeO{sub 3}, at elevated temperatures. The sharp phase boundaries between the structural phases are observed to align with the crystal planes of the hexagonal LuFeO{sub 3} phase. The coexistence of different structural domains indicates that the irreversible structural transition, from the hexagonal to the orthorhombic phase in LuFeO{sub 3}, is a first order transition, for epitaxial hexagonal LuFeO{sub 3} films grown on Al{sub 2}O{sub 3}.

  12. (BMI)3LnCl6 crystals as models for the coordination environment of LnCl3 (Ln = Sm, Eu, Dy, Er, Yb) in 1-butyl-3-methylimidazolium chloride ionic-liquid solution.

    PubMed

    Han, Yulun; Lin, Cuikun; Meng, Qingguo; Dai, Fengrong; Sykes, Andrew G; Berry, Mary T; May, P Stanley

    2014-06-02

    A series of (BMI)3LnCl6 (Ln = Sm, Eu, Dy, Er, Yb) crystals was prepared from solutions of LnCl3 dissolved in the ionic liquid, 1-butyl-3-methylimidazolium chloride (BMICl). Crystals with Ln = 5% Sm + 95% Gd and with Ln = 5% Dy + 95% Gd were also grown to assess the importance of cross-relaxation in the Sm and Dy samples. The crystals are isostructural, with monoclinic space group P21/c and four formula units per unit cell. The first coordination sphere of Ln(3+) consists of six Cl(-) anions forming a slightly distorted octahedral LnCl6(3-) center. The second coordination sphere is composed of nine BMI(+) cations. The emission spectra and luminescence lifetimes of both (BMI)3LnCl6 crystals and LnCl3 in BMICl solution were measured. The spectroscopic similarities suggest that crystalline (BMI)3LnCl6 provides a good model of the Ln(3+) coordination environment in BMICl solution.

  13. Charge-transfer luminescence and spectroscopic properties of Yb 3+ in aluminium and gallium garnets

    NASA Astrophysics Data System (ADS)

    Guerassimova, N.; Dujardin, C.; Garnier, N.; Pédrini, C.; Petrosyan, A. G.; Kamenskikh, I. A.; Mikhailin, V. V.; Shpinkov, I. N.; Spassky, D. A.; Ovanesyan, K. L.; Shirinyan, G. O.; Chipaux, R.; Cribier, M.; Mallet, J.; Meyer, J.-P.

    2002-06-01

    Luminescence of Yb 3+ from the charge-transfer state with broad emission bands and short radiative lifetimes (few to tens of nanoseconds depending on the host lattice and the temperature) is attractive for the development of fast scintillators capable of discriminating very short events. The most important currently considered application is that in solar neutrino ( νe) real-time spectroscopy, since the νe capture by 176Yb is followed by a specific emission signature which can accordingly excite the Yb 3+ fluorescence. Studies on scintillation and luminescence in aluminium garnets containing Yb 3+ have shown that these materials meet some of the required properties for such scintillators. In defining our priorities, the best compromise between host crystal, Yb 3+ concentration, production method, post-growth treatment and performance is to be considered based on the studies of charge-transfer luminescence and quenching mechanisms. The experiments have been extended to a large number of compounds: YAG:Yb-YbAG, YGG:Yb-YbGG, YAP:Yb-YbAP, LaYbO 3 in the form of single crystals and/or powders. In garnets, the temperature-dependent fluorescence intensity and decay time under X-ray and VUV excitations decrease at low temperatures ( T<100 K) and demonstrate the important role played by the traps. The thermoluminescence peaks show a strong dependence on the crystal history, composition and impurities introduced intentionally. The fluorescence intensity and decay time are also dependent on Yb 3+ concentration and the presence of Yb 2+. The results trace the major directions to optimised scintillators in terms of their efficiency and lifetime.

  14. Electric polarization observed in single crystals of multiferroic Lu2MnCoO6

    SciTech Connect

    Chikara, Shalinee; Singleton, John; Bowlan, John M.; Yarotski, Dmitry Anatolievitch; Lee, N.; Choi, H. Y.; Choi, Y. J.; Zapf, Vivien S.

    2016-05-17

    We report electric polarization and magnetization measurements in single crystals of double perovskite Lu2MnCoO6 using pulsed magnetic fields and optical second harmonic generation in dc magnetic fields. We observe well-resolved magnetic field-induced changes in the electric polarization in single crystals and thereby resolve the question about whether multiferroic behavior is intrinsic to these materials or is an extrinsic feature of polycrystals. We find electric polarization along the crystalline b axis, that is suppressed by applying a magnetic fields along the c axis, and advance a model for the origin of magnetoelectric coupling. We furthermore map the phase diagram using both capacitance and electric polarization to identify regions of ordering and regions of magnetoelectric hysteresis. This compound is a rare example of coupled hysteretic behavior in the magnetic and electric properties. Furthermore, the ferromagneticlike magnetic hysteresis loop that couples to hysteretic electric polarization can be attributed not to ordinary ferromagnetic domains, but to the rich physics of magnetic frustration of Ising-like spins in the axial next-nearest-neighbor interaction model.

  15. Electric polarization observed in single crystals of multiferroic Lu2MnCoO6

    SciTech Connect

    Chikara, Shalinee; Singleton, John; Bowlan, John M.; Yarotski, Dmitry Anatolievitch; Lee, N.; Choi, H. Y.; Choi, Y. J.; Zapf, Vivien S.

    2016-05-17

    We report electric polarization and magnetization measurements in single crystals of double perovskite Lu2MnCoO6 using pulsed magnetic fields and optical second harmonic generation in dc magnetic fields. We observe well-resolved magnetic field-induced changes in the electric polarization in single crystals and thereby resolve the question about whether multiferroic behavior is intrinsic to these materials or is an extrinsic feature of polycrystals. We find electric polarization along the crystalline b axis, that is suppressed by applying a magnetic fields along the c axis, and advance a model for the origin of magnetoelectric coupling. We furthermore map the phase diagram using both capacitance and electric polarization to identify regions of ordering and regions of magnetoelectric hysteresis. This compound is a rare example of coupled hysteretic behavior in the magnetic and electric properties. Furthermore, the ferromagneticlike magnetic hysteresis loop that couples to hysteretic electric polarization can be attributed not to ordinary ferromagnetic domains, but to the rich physics of magnetic frustration of Ising-like spins in the axial next-nearest-neighbor interaction model.

  16. Magnesium substitutions in rare-earth metal germanides with the orthorhombic Gd5Si4-type structure. Synthesis, crystal chemistry, and magnetic properties of RE(5-x)Mg(x)Ge4 (RE = Gd-Tm, Lu, and Y).

    PubMed

    Tobash, Paul H; Bobev, Svilen; Thompson, Joe D; Sarrao, John L

    2009-07-20

    A series of magnesium-substituted rare-earth metal germanides with a general formula RE(5-x)Mg(x)Ge(4) (x approximately = 1.0-2.3; RE = Gd-Tm, Lu, Y) have been synthesized by high-temperature reactions and structurally characterized by single-crystal X-ray diffraction. These compounds crystallize with the common Gd(5)Si(4) type structure in the orthorhombic space group Pnma (No. 62; Z = 4; Pearson's code oP36) and do not appear to undergo temperature-induced crystallographic phase transitions down to 120 K. Replacing rare-earth metal atoms with Mg, up to nearly 45% at., reduces the valence electron count and is clearly expressed in the subtle changes of the Ge-Ge and metal-metal bonding. Magnetization measurements as a function of the temperature and the applied field reveal complex magnetic structures at cryogenic temperatures and Curie-Weiss paramagnetic behavior at higher temperatures. The observed local moment magnetism is consistent with RE(3+) ground states in all cases. In the magnetically ordered phases, the magnetization cannot reach saturation in fields up to 50 kOe. The structural trends across the series and the variations of the magnetic properties as a function of the Mg content are also discussed.

  17. Orthoborates LiCdRE5(BO3)6 (RE = Sm-Lu and Y) with Rare-Earth Ions on a Triangular Lattice: Synthesis, Crystal Structure, and Optical and Magnetic Properties.

    PubMed

    Xia, Mingjun; Zhai, Kun; Lu, Jun; Sun, Young; Li, R K

    2017-07-17

    Single crystals of LiCdY5(BO3)6 were successfully grown from a Li2O-B2O3 flux, and its lanthanide homotypic compounds, LiCdRE5(BO3)6 (RE = Sm-Lu), have been prepared by solid-state reaction. They crystallize in the noncentrosymmetric space group P6522 with cell parameters in the ranges of a = 7.0989(2)-6.9337(1) Å and c = 25.9375(1)-24.8960(6) Å. As a representative example, LiCdY5(BO3)6 features a triangular lattice in the ab plane composed of three distinct crystallographic Y sites. The triangular lattices spaced with the same distance of [Formula: see text]c are further stacked to build three-dimensional frameworks by reinforcement of the isolated planar BO3 groups and distorted LiO4 tetrahedra. Magnetic measurements show that Eu and Sm compounds exhibit typical Van Vleck-type paramagnetism and other rare-earth borates show weak antiferromagnetic behavior. In addition, UV-vis-near-IR diffuse-reflectance and photoluminescence spectra were performed to understand the transition energy levels of active rare-earth ions and their relationships to magnetism.

  18. Neutron-scattering studies of Yb-bearing silicate glasses

    SciTech Connect

    Ellison, A.J.G.; Loong, C.K.; Wagner, J.

    1993-09-01

    The static and dynamic magnetic response of the Yb{sup 3+} ions in 2Na{sub 2}O{center_dot}Yb{sub 2}O{sub 3}{center_dot}6SiO{sub 2} glass and the isochemical crystalline silicate Na{sub 3}YbSi{sub 3}O{sub 9} has been studied by neutron diffraction, inelastic magnetic-scattering, and magnetic susceptibility measurements. The rare earth sites in the glass have an average coordination number of 5.6 {plus_minus} 0.5 and give a mean rare earth-oxygen bond length of 2.23 {Angstrom}; average Si-O and O-O coordination numbers and bond distances are comparable to those in vitreous SiO{sub 2}. The magnetic excitation spectrum of the Na{sub 3}YbSi{sub 3}O{sub 9} material was analyzed by a crystal-field model using a method of descending symmetry. The magnetic susceptibility and the excitation spectrum of the Yb glasses can be described by a distribution of ligand-field effects on the Yb{sup 3+} ions that are similar to the nominal crystal field in crystalline Na{sub 3}YbSi{sub 3}O{sub 9}.

  19. UV-visible Faraday rotators based on rare-earth fluoride single crystals: LiREF4 (RE = Tb, Dy, Ho, Er and Yb), PrF3 and CeF3.

    PubMed

    Vasyliev, Valentyn; Villora, Encarnacíon G; Nakamura, Masaru; Sugahara, Yoshiyuki; Shimamura, Kiyoshi

    2012-06-18

    High optical quality LiREF(4) (RE = Tb(3+), Dy(3+), Ho(3+), Er(3+) and Yb(3+)), PrF(3) and CeF(3) single crystals have been grown by the Czochralski technique. Their magneto-optical properties have been measured and analyzed in detail in the ultraviolet-visible wavelength region, and their figures of merit as Faraday rotators have been determined. CeF(3) presents superior properties above 300 nm, showing a figure of merit higher than that of the reference material, terbium-gallium-garnet, which is nowadays used in the visible-near infrared. PrF(3) is the best rotator for the 220-300 nm range. Towards shorter wavelength and in the vacuum ultraviolet, it is shown that the LiREF(4) crystals are unique rotators. Overall, the rare-earth fluoride single crystals studied here exhibit better properties than other materials considered so far, and therefore they have potential to cover the increasing demand for new and improved Faraday rotators in the ultraviolet-visible wavelength region.

  20. Near infrared downconversion in Pr 3+-Yb 3+ codoped oxyfluoride glass ceramics

    NASA Astrophysics Data System (ADS)

    Katayama, Yumiko; Tanabe, Setsuhisa

    2010-12-01

    The loss mechanism in the Pr 3+-Yb 3+ codoped glass that showed quantum cutting (QC) phenomenon was investigated and we found that the multi-phonon relaxation from Pr 3+: 1G 4 is the major loss to the quantum cutting process. To reduce the loss, Pr 3+-Yb 3+ codoped glass ceramics containing SrF 2 crystals were prepared and quantum yields (QY) of Yb 3+ emission by 440 nm excitation were measured. Only glass ceramics with the highest Yb concentration ( x = 2.9) showed higher QY than that of the as-made glass. It is considered that in low Yb concentration Pr 3+ and Yb 3+ ions were divided into different matrix possibly because of different ionic radius between Pr 3+ and Yb 3+ ions.

  1. Synthesis, crystal structure and properties of Mg3B36Si9C and related rare earth compounds RE3-xB36Si9C (RE=Y, Gd-Lu)

    NASA Astrophysics Data System (ADS)

    Ludwig, Thilo; Pediaditakis, Alexis; Sagawe, Vanessa; Hillebrecht, Harald

    2013-08-01

    We report on the synthesis and characterisation of Mg3B36Si9C. Black single crystals of hexagonal shape were yielded from the elements at 1600 °C in h-BN crucibles welded in Ta ampoules. The crystal structure (space group R3barm, a=10.0793(13) Å, c=16.372(3) Å, 660 refl., 51 param., R1(F)=0.019; wR2(F2)=0.051) is characterized by a Kagome-net of B12 icosahedra, ethane like Si8-units and disordered SiC-dumbbells. Vibrational spectra show typical features of boron-rich borides and Zintl phases. Mg3B36Si9C is stable against HF/HNO3 and conc. NaOH. The micro-hardness is 17.0 GPa (Vickers) and 14.5 GPa (Knoop), respectively. According to simple electron counting rules Mg3B36Si9C is an electron precise compound. Band structure calculations reveal a band gap of 1.0 eV in agreement to the black colour. Interatomic distances obtained from the refinement of X-ray data are biased and falsified by the disorder of the SiC-dumbbell. The most evident structural parameters were obtained by relaxation calculation. Composition and carbon content were confirmed by WDX measurements. The small but significant carbon content is necessary by structural reasons and frequently caused by contaminations. The rare earth compounds RE3-xB36Si9C (RE=Y, Dy-Lu) are isotypic. Single crystals were grown from a silicon melt and their structures refined. The partial occupation of the RE-sites fits to the requirements of an electron-precise composition. According to the displacement parameters a relaxation should be applied to obtain correct structural parameters.

  2. Light yield and light loss coefficient of LuAG:Ce and LuAG:Pr under excitation with α- and γ-rays

    NASA Astrophysics Data System (ADS)

    Sreebunpeng, Krittiya; Chewpraditkul, Weerapong; Nikl, Martin

    2017-06-01

    Light yield and light loss coefficient of Lu3Al5O12:Ce (LuAG:Ce) and Lu3Al5O12:Pr (LuAG:Pr) single crystals grown by the Czochralski method were investigated under excitation with α- and γ-rays. Photoelectron yield and energy resolution were measured using the XP5200B photomultiplier. The dependence of photoelectron yield on sample height was measured under excitation with α- and γ-rays and the light loss coefficient was evaluated. It was found that the light loss coefficient of LuAG:Ce is smaller than that of LuAG:Pr. The ratio of photoelectron yield under excitation with α- and γ-rays (α/γ ratio) was also determined and discussed.

  3. Crystal structure, morphotropic phase transition and luminescence in the new cyclosilicates Sr{sub 3}R{sub 2}(Si{sub 3}O{sub 9}){sub 2}, R=Y, Eu-Lu

    SciTech Connect

    Tyutyunnik, Alexander P.; Leonidov, Ivan I.; Surat, Ludmila L.; Berger, Ivan F.; Zubkov, Vladimir G.

    2013-01-15

    A new series of promising luminescent materials, cyclosilicates Sr{sub 3}R{sub 2}(Si{sub 3}O{sub 9}){sub 2}, R=Y, Eu-Lu, has been synthesized via a solid-state reaction. X-ray and neutron powder diffraction studies show that these oxides crystallize in the monoclinic crystal system (S.G. C2/c, Z=4) and have a morphotropic phase transition between Er and Tm compounds followed by a step-like change of the unit cell constants. Isolated [Si{sub 3}O{sub 9}] rings located in layers are basic building units and stack with Sr/R layers along the [1 0 1{sup Macron }] direction. The rare earth atoms are distributed among three independent Sr/R sites coordinated by 8, 7 and 6 oxygen atoms, and the Sr-R populations change from mixed to 0.5/0.5 over site (1) and full occupation of sites (2) and (3) by Sr and R, respectively, at the transition. Changes of the conformation and mutual arrangement of [Si{sub 3}O{sub 9}] rings, as well as exchange of oxygen atoms from the first and the second coordination sphere of two Sr/R sites also feature the phase transition. Luminescence in Sr{sub 3}Y{sub 2}(Si{sub 3}O{sub 9}){sub 2}:Eu{sup 3+} under ultraviolet (UV) excitation has been discussed. - Graphical abstract: The change of the [Si{sub 3}O{sub 9}] ring conformation in Sr{sub 3}R{sub 2}(Si{sub 3}O{sub 9}){sub 2}, R=Eu, Er, Tm and Lu. Highlights: Black-Right-Pointing-Pointer A new group of cyclosilicates Sr{sub 3}R{sub 2}(Si{sub 3}O{sub 9}){sub 2}, R=Y, Eu-Lu, was first synthesized. Black-Right-Pointing-Pointer Isolated [Si{sub 3}O{sub 9}] rings located in layers are basic building units and stack with Sr/R layers along the [1 0 1{sup Macron }] direction. Black-Right-Pointing-Pointer The rare earth atoms are distributed among three independent Sr/R sites coordinated by 6, 7 and 8 oxygen ligands. Black-Right-Pointing-Pointer A step-like change of the unit cell parameters is observed in the Sr{sub 3}R{sub 2}(Si{sub 3}O{sub 9}){sub 2} structure for R=Er{yields}Tm. Black

  4. Production of 177Lu, a potential radionuclide for diagnostic and therapeutic applications

    NASA Astrophysics Data System (ADS)

    Khandaker, Mayeen Uddin; Haba, Hiromitsu; Kassim, Hasan Abu

    2015-04-01

    177gLu (T1/2=6.647d; Eβ-max=498.3 KeV, Iβ-total=100 % ; Eγ = 112.9498 keV, Iγ = 6.17%; Eγ = 208.3662 keV, I γ = 10.36%) is widely used in many clinical procedures due to its excellent decay characteristics. Production cross-sections of the natYb(d,x)177gLu reactions have been measured from a 24-MeV deuteron energy down to the threshold by using a stacked-foil activation technique combined with high resolution γ-ray spectrometry. An overall good agreement is found with some of the earlier measurements, whereas a partial agreement is obtained with the theoretical data extracted from the TENDL-2013 library. Physical thick target yield for the 177gLu radionuclide was deduced using the measured cross-sections. The deduced yield curves indicate that a low energy (<11 MeV) cyclotron and a highly enriched 176Yb target could be used to obtain 177gLu with negligible impurity from 177mLu.

  5. Production of {sup 177}Lu, a potential radionuclide for diagnostic and therapeutic applications

    SciTech Connect

    Khandaker, Mayeen Uddin; Kassim, Hasan Abu; Haba, Hiromitsu

    2015-04-24

    {sup 177g}Lu (T{sub 1/2}=6.647d; E{sub β{sup −max}}=498.3KeV, I{sub β{sup −total}}=100%; E{sub γ} = 112.9498 keV, I{sub γ} = 6.17%; E{sub γ} = 208.3662 keV, I {sub γ} = 10.36%) is widely used in many clinical procedures due to its excellent decay characteristics. Production cross-sections of the {sup nat}Yb(d,x){sup 177g}Lu reactions have been measured from a 24-MeV deuteron energy down to the threshold by using a stacked-foil activation technique combined with high resolution γ-ray spectrometry. An overall good agreement is found with some of the earlier measurements, whereas a partial agreement is obtained with the theoretical data extracted from the TENDL-2013 library. Physical thick target yield for the {sup 177g}Lu radionuclide was deduced using the measured cross-sections. The deduced yield curves indicate that a low energy (<11 MeV) cyclotron and a highly enriched {sup 176}Yb target could be used to obtain {sup 177g}Lu with negligible impurity from {sup 177m}Lu.

  6. Lu-Hf and PbSL geochronology of apatites from Proterozoic terranes: A first look at Lu-Hf isotopic closure in metamorphic apatite

    NASA Astrophysics Data System (ADS)

    Barfod, Gry Hoffmann; Krogstad, Eirik Jens; Frei, Robert; Albarède, Francis

    2005-04-01

    The mineral apatite is characterized by elevated and highly variable Lu/Hf ratios that, in some cases, allow for single-crystal dating by the Lu-Hf isotopic system. Apatites from the Adirondack Lowlands and Otter Lake area in the Grenville Province, and from the Black Hills, South Dakota, yield Lu-Hf ages that are consistently older than their respective Pb step leaching ages. Isotopic closure for the Lu-Hf system, therefore, occurs before U-Pb system closure in this mineral. In the Adirondack Lowlands, where H 2O activity was low, Lu-Hf systematics of cm-sized apatite crystals remained undisturbed during upper amphibolite facies metamorphism (˜700 to 675 °C) at 1170-1130 Ma. The relatively old Lu-Hf ages of 1270 and 1230 Ma observed for these apatites correlate with decreasing crystal size. In contrast, apatite from the fluid-rich Otter Lake area and Black Hills yields unrealistically low apparent Lu-Hf closure temperatures, implying that in these apatites, fluids facilitated late exchange. The Lu-Hf ages for the metamorphic apatites were thus controlled either by the prevailing temperature and grain size, or by fluid activity.

  7. Single- and dual-wavelength lasers of diode-pumped Nd:LuYAG mixed crystal on various 4F3/2  →  4I13/2 Stark-level transitions

    NASA Astrophysics Data System (ADS)

    Lan, Jinglong; Wang, Yi; Huang, Xiaoxu; Lin, Zhi; Xu, Bin; Xu, Huiying; Cai, Zhiping; Xu, Xiaodong; Xu, Jun

    2016-08-01

    A diode-end-pumped Nd:LuYAG mixed crystal laser in the 1.3 μm spectral domain using a simple and compact two-mirror laser cavity is reported for the first time to our knowledge. In the free-running laser operation, we obtain a simultaneous dual-wavelength laser at about 1319 and 1338 nm with a maximum output power of 2.92 W and a slope efficiency of about 26.7%. By inserting an undoped YAG etalon into the laser cavity, the two 1319 and 1338 nm lasers can be operated singly with the maximum output powers of 1.36 and 1.73 W. Moreover, three simultaneous dual-wavelength lasers at 1334.67 and 1340.93 nm, 1319.15 and 1354.57 nm, and 1335.54 and 1354.94 nm can also be yielded with maximum output powers of 1.02, 0.66, and 0.47 W as well as slope efficiencies of 12.3%, 8.9%, and 6.9%, respectively. These dual-wavelength laser sources provide potential THz wave generation by beat frequency.

  8. Eleven new compounds in the RE-Cd-Ge systems (RE=Pr, Nd, Sm, Gd-Yb; Y): Crystal chemistry of the RE2CdGe2 series

    NASA Astrophysics Data System (ADS)

    Guo, Sheng-Ping; Meyers, John J.; Tobash, Paul H.; Bobev, Svilen

    2012-08-01

    A large new family of rare-earth metal-cadmium-germanides RE2CdGe2 (RE=Y, Pr, Nd, Sm, Gd-Yb) has been synthesized and structurally characterized. All eleven structures have been established from single-crystal X-ray diffraction data and have been found to belong to the tetragonal Mo2FeB2 structure type (ordered ternary variant of the U3Si2 structure type—space group P4/mbm (No. 127), Z=2; Pearson symbol tP10). The structural variations among the three series of isostructural RE2MgGe2, RE2InGe2, and RE2CdGe2 compounds are discussed, as well as the crystal chemistry changes as a function of the decreasing size of the rare-earth metals (lattice constants a=7.176(2)-7.4589(12) Å and c=4.1273(14)-4.4356(13) Å). The experimental results have been complemented by tight-binding linear muffin-tin orbital (TB-LMTO) electronic structure calculations.

  9. Phonon Drag and Magnetic Anomalies, of Thermopower, in RB12 (R = Ho, Er, Tm, Lu)

    NASA Astrophysics Data System (ADS)

    Glushkov, V.; Demishev, S.; Ignatov, M.; Khayrullin, E.; Sluchanko, N.; Shitsevalov, N.; Levchenko, A.; Filipov, V.; Flachbart, K.; Siemensmeyer, K.

    2008-01-01

    High precision measurements of the Seebeck coefficient S(T) were carried out on the single crystals of RB12 (R = Ho, Er, Tm, Lu) at temperatures 2-300 K. It was shown that the effects of phonon drag result from vibrations of rare earth ions (ℏ ωE≈10-33 meV) in the rigid framework structure of the B12 clusters and determine the main contribution to thermopower at intermediate temperatures (30-300 K). The correlated behavior of transport parameters favors the appreciable enhancement of spin fluctuations in the sequence of magnetic compounds (HoB12-TmB12) when approaching to the valence instability state in YbB12. The giant increase in S(T) detected in the vicinity of the Néel temperature TN for HoB12, ErB12, and TmB12 seems to result from the density of states renormalization caused by antiferromagnetic ordering.

  10. Flashlamp-pumped Ho:Tm:Cr:LuAG laser

    NASA Technical Reports Server (NTRS)

    Jani, Mahendra G. (Inventor); Barnes, Norman P. (Inventor); Murray, Keith E. (Inventor); Kokta, Milan R. (Inventor)

    1997-01-01

    A room temperature solid-state laser is provided. A laser crystal is disposed in a laser cavity. The laser crystal has a LuAG host material doped with a concentration of about 0.35% Ho ions, about 5.57% Tm ions and at least about 1.01% Cr ions. A broadband energizing source such as a flashlamp is disposed transversely to the laser crystal to energize the Ho ions, Tm ions and Cr ions.

  11. Efficient Yb³⁺:CaGdAlO₄ bulk and femtosecond-laser-written waveguide lasers.

    PubMed

    Hasse, Kore; Calmano, Thomas; Deppe, Bastian; Liebald, Christoph; Kränkel, Christian

    2015-08-01

    We report on, to the best of our knowledge, the first fs-laser-written waveguide laser in Yb3+:CaGdAlO4 (Yb:CALGO). With Yb:CALGO crystals grown in our labs, we obtained a slope efficiency of 69% and up to 2.4 W of continuous wave (cw) output power in a waveguide-laser configuration. Moreover, bulk laser experiments with Yb:CALGO were performed, and slope efficiencies up to 73%, optical-to-optical efficiencies of 65%, and maximum cw output powers of 3.3 W were reached. These are the highest efficiencies in the laser configuration with Yb:CALGO.

  12. Crystal Chemistry and Magnetism of Ternary Actinoid Boron Carbides UB 1- xC 1+ x and U 1- xMxB 2C with M = Sc, Lu, and Th

    NASA Astrophysics Data System (ADS)

    Rogl, P.; Rupp, B.; Felner, I.; Fischer, P.

    1993-06-01

    Within the homogeneous range of uranium monocarbide UB 1- xC 1+ x, the crystal structures of stoichiometric UBC and of the carbon-rich solid solution UB 0.78C 1.22, have been refined from single-crystal X-ray counter data. From X-ray analysis crystal symmetry in both cases is consistent with the centro-symmetric space group Cmcm and there are no indications of superstructure formation. In contrast to the fully ordered atom arrangement revealed for stoichiometric UBC ( a = 0.35899(4), b = 1.19781(12), c = 0.33474(3) nm), random occupation by boron and carbon atoms is observed for the boron site in UB 0.78C 1.22 ( a = 0.35752(4), b = 1.18584(3), c = 0.33881(4) nm). For 279(278) reflections (|F 0| > 3σ) the obtained reliability factors R x = ∑|ΔF|/∑| F0| were R x = 0.069 for UBC and R x = 0.050 for UB 0.78C 1.22. Neutron powder diffraction experiments at 9 and 295 K unambiguously revealed full occupancy by the nonmetal atoms in UB 0.78C 1.22 and prove the statistical occupation of B and C atoms in the B-sites. For the orthorhombic symmetry Cmcm, refinement was not better than R1 = 0.044. A model calculation in monoclinic symmetry C12/ m1, however, resulted in a significant reduction of the residual value to R1 = 0.030, releasing spatial constraints on the boron atoms. Thus the boron-boron chain in Cmcm (B-B = 0.1874 nm) is dissolved into boron pairs (B-B = 0.1706 nm) which are loosely bound at a distance of 0.2043 nm. The formation of C-B-B-C groups corresponds to the structure types of ThBC and Th 3B 2C 3. The magnetic behavior has been investigated in the temperature range from 4.2 K to 1000 K for UB 1- xC 1+ x (UBC-type) and U 1- xMxB 2C (ThB 2C-type for the high temperature modification and 1-UB 2C-type for the low temperature modification) with U partially substituted by Th or Sc, Lu. From magnetic susceptibilities, the alloys UB 1- xC 1+ x reveal temperature independent paramagnetism with typical intermediate valence fluctuation behavior ( TSF ˜ 350 K

  13. Continuous wave Yb:YCOB cyan lasers with KTP as the sum-frequency converter

    NASA Astrophysics Data System (ADS)

    Lan, Ruijun; Cheng, Hao; Yang, Guang

    2015-12-01

    All-solid-state cyan laser at 500 nm range are reported based on a Yb:YCa4O(BO3)3 (Yb:YCOB) crystal and a type-II phase matched KTiOPO4 (KTP) crystal. The 503 nm cyan laser is obtained by the sum-frequency mixing (SFM) of 974 nm pump wave and 1042 nm fundamental wave. To the best of our knowledge, this is the first cyan laser demonstrated with Yb-doped YCOB crystal. A dual-wavelength laser at 505 and 525 nm is also obtained, which origins from the simultaneous SFM and self-frequency doubling.

  14. Microstructure, optical, and scintillation characteristics of Pr3+ doped Lu3Al5O12 optical ceramics

    NASA Astrophysics Data System (ADS)

    Shi, Yun; Nikl, Martin; Feng, Xiqi; Mares, Jiri A.; Shen, Yiqiang; Beitlerova, A.; Kucerkova, R.; Pan, Yubai; Liu, Qian

    2011-01-01

    0.5, 1.0, and 5.0 at. % Pr3+ doped Lu3Al5O12 (Pr:LuAG) optical ceramics are fabricated and compared with Bi4Ge3O12 (BGO) and Pr:LuAG single crystals as for their optical, luminescence and scintillation properties. Radio-luminescence intensity of the fast UV emission based on 5d1→4f Pr3+ transition reaches up to 20 times of that of BGO single crystal reference scintillator. Photoelectron yield of the best performing 0.5 at. % Pr:LuAG ceramic sample is about 1002 phels/MeV, about 30% lower than that of BGO reference sample and about 65% lower than that of Pr:LuAG single crystal. The trapping phenomena at grain boundaries and/or structural defects are proposed as the main cause of degradation of the scintillation response of the Pr:LuAG optical ceramics.

  15. Optical and physical properties of ceramic crystal laser materials

    NASA Astrophysics Data System (ADS)

    Simmons, Jed A.

    spectra, and fluorescence lifetime were measured for Nd:YAG ceramic crystal and Yb:Lu2O3 ceramic crystal. No apparent inhomogeneous broadening appears to exist in the Nd:YAG ceramic at low concentrations. Concentration and temperature dependence effects on emission spectra were measured and are presented. Laser action in a thin disk of Yb:Y2O3 ceramic crystal was achieved. Pumping was accomplished with a fiber coupled diode laser stack at 938 nm. A slope efficiency of 34% was achieved with maximum output energy of 28.8 mJ/pulse.

  16. Quasi-two-dimensional spin correlations in the triangular lattice bilayer spin glass LuCoGaO4

    NASA Astrophysics Data System (ADS)

    Fritsch, K.; Ross, K. A.; Granroth, G. E.; Ehlers, G.; Noad, H. M. L.; Dabkowska, H. A.; Gaulin, B. D.

    2017-09-01

    We present a single-crystal time-of-flight neutron scattering study of the static and dynamic spin correlations in LuCoGaO4, a quasi-two-dimensional dilute triangular lattice antiferromagnetic spin-glass material. This system is based on Co2 + ions that are randomly distributed on triangular bilayers within the YbFe2O4 -type, hexagonal crystal structure. Antiferromagnetic short-range two-dimensional correlations at wave vectors Q =(" close=")1 /3 ,1 /3 ,L )">1 /3 ,1 /3 ,L develop within the bilayers at temperatures as high as | ΘCW|˜100 K and extend over roughly five unit cells at temperatures below Tg=19 K. These two-dimensional static correlations are observed as diffuse rods of neutron scattering intensity along c* and display a continuous spin freezing process in their energy dependence. Aside from exhibiting these typical spin-glass characteristics, this insulating material reveals a novel gapped magnetic resonant spin excitation at Δ E ˜12 meV localized around Q. The temperature dependence of the spin gap associated with this two-dimensional excitation correlates with the evolution of the static correlations into the spin-glass state ground state. We associate it with the effect of the staggered exchange field acting on the Seff=1 /2 Ising-like doublet of the Co2 + moments.

  17. Effect of reducing Lu3+ content on the fabrication and scintillation properties of non-stoichiometric Lu3-xAl5O12:Ce ceramics

    NASA Astrophysics Data System (ADS)

    Liu, Shuping; Mares, Jiri A.; Babin, Vladimir; Hu, Chen; Kou, Huamin; D'Ambrosio, Carmelo; Pan, Yubai; Nikl, Martin

    2017-01-01

    Lu3-xAl5O12:Ce optical ceramics (Lu3-xAG:Ce, x = 1, 2, 3 and 4 at.%, respectively) with Lu3+ compositions ranging from 1 to 4 at.% below stoichiometry content were fabricated by solid state reaction method and further optimized by an air-annealing process. The effect of Lu3+ deficiency on the optical, luminescence and scintillation properties of such a non-stoichiometric Lu3-xAl5O12:Ce ceramics was investigated. Significant influence in the material densification was found leading to strong changes in the transparency, radioluminescence (RL) and scintillation response of these ceramics. Within the range of 1-4 at.% Lu3+ deficiency, LuAl antisite defects were suppressed effectively and the Lu3-xAG:Ce ceramics displayed an extremely high RL intensity which reaches ∼4 times higher than that of the latest commercial LuAG:Ce single crystals while its transparency deteriorated. The microstructure, presence of foreign phases and charge traps acting in scintillation mechanism were also characterized by means of SEM, back scattered electron imaging and thermoluminescence techniques, respectively.

  18. Growth and luminescent properties of Lu 2SiO 5 and Lu 2SiO 5:Ce single crystalline films

    NASA Astrophysics Data System (ADS)

    Zorenko, Yu.; Nikl, M.; Gorbenko, V.; Savchyn, V.; Voznyak, T.; Kucerkova, R.; Sidletskiy, O.; Grynyov, B.; Fedorov, A.

    2011-04-01

    Single crystalline films (SCF) of Lu 2SiO 5 (LSO) and Lu 2SiO 5:Ce (LSO:Ce) silicates with thickness of 2.5-15 μm were crystallized by liquid phase epitaxy method onto undoped LSO substrates from melt-solution based on PbO-B 2O 3 flux. The scintillation and luminescence properties of LSO:Ce SCF were compared with the properties of LSO:Ce single crystal. The peculiarities of luminescence properties of LSO:Ce SCF in comparison with crystal analog can be due to different distribution of Ce 3+ over the Lu1 and Lu2 positions of LSO host and are further influenced by Pb 2+ flux-originated contamination.

  19. Crystal and electronic structures of CaAl 2Si 2-type rare-earth copper zinc phosphides RECuZnP 2 ( RE=Pr, Nd, Gd-Tm, Lu)

    NASA Astrophysics Data System (ADS)

    Blanchard, Peter E. R.; Stoyko, Stanislav S.; Cavell, Ronald G.; Mar, Arthur

    2011-01-01

    The quaternary rare-earth phosphides RECuZnP 2 ( RE=Pr, Nd, Gd-Tm, Lu) have been prepared by reaction of the elements at 900 °C, completing this versatile series which forms for nearly all RE metals. They adopt the trigonal CaAl 2Si 2-type structure (Pearson symbol hP5, space group P3¯ m1, Z=1), as confirmed by single-crystal X-ray diffraction analysis on ErCuZnP 2 and powder X-ray diffraction analysis on the remaining members. The Cu and Zn atoms are assumed to be disordered over the single transition-metal site. Band structure calculations on a hypothetically ordered YCuZnP 2 model suggest a semimetal, with a zero band gap between the valence and conduction bands. This electronic structure is supported by XPS valence band spectra for RECuZnP 2 ( RE=Gd-Er), in which the intensity drops off smoothly at the Fermi edge. The absence of a band gap permits the electron count to deviate from the precise value of 16 e - per formula unit, as demonstrated by the formation of a solid solution in GdCu xZn 2- xP 2 (1.0≤ x≤1.3), while still retaining the CaAl 2Si 2-type structure. Because the Cu 2 p XPS spectra indicate that the Cu atoms are always monovalent, the substitution of Cu for Zn leads to a decrease in electron count and a lowering of the Fermi level in the valence band. The magnetic susceptibility of RECuZnP 2 ( RE=Gd-Er), which obeys the Curie-Weiss law, confirms the presence of trivalent RE atoms.

  20. LU-HF Age and Isotope Systematics of ALH84001

    NASA Technical Reports Server (NTRS)

    Righter, M.; Lapen, T. J.; Brandon, A. D.; Beard, B. L.; Shafer, J. T.; Peslier, A. H.

    2009-01-01

    Allan Hills (ALH) 84001 is an orthopyroxenite that is unique among the Martian meteorites in having the oldest inferred crystallization age (approx..4.5 to 4.0 Gyr) [e.g., 1-6 and references therein 7]. Its ancient origin makes this stone a critical constraint on early history of Mars, in particular the evolution of different planetary crust and mantle reservoirs. However, because there is significant variability in reported crystallization ages, determination of initial isotope compositions is imprecise making assessment of planetary reservoirs difficult. Here we report a new Lu-Hf mineral isochron age, initial Hf-176/Hf-177 isotope composition, and inferred Martian mantle source compositions for ALH84001 that place constraints on longlived source reservoirs for the enriched shergottite suite of Martian meteorites including Shergotty, Zagami, NWA4468, NWA856, RBT04262, LAR06319, and Los Angeles. Sm-Nd isotope analyses are under way for the same mineral aliquots analyzed for Lu-Hf. The Lu-Hf system was utilized because Lu and Hf are both lithophile and refractory and are not easily redistributed during short-lived thermal pulses associated with shock metamorphism. Moreover, chromite has relatively modest Hf concentrations with very low Lu/Hf ratios [9] yielding tight constraints on initial Hf-176/Hf-177 isotope compositions

  1. Yb{sup 3+}:BaCaBO{sub 3}F: A potential new self-frequency-doubling laser material

    SciTech Connect

    Schaffers, K.I.; DeLoach, L.D.; Ebbers, C.A.; Payne, S.A.

    1995-03-09

    Yb:BaCaBO{sub 3}F (Yb:BCBF) has been investigated as a new laser crystal with potential for self-frequency-doubling. An YB:BCBF laser has been pumped at 912 mm, and a measured slope efficiency of 38% has been obtained for the fundamental laser output at 1034 nm. Single crystal powders of BCBF have been compared with K*P for a relative measure of the second harmonic generating potential, yielding d{sub eff}[BCBF]= (0-66)d{sub eff}[K*P]. The growth, spectroscopy, laser performance, and linear and nonlinear optical properties of YB:BCBF are reported here.

  2. Method for fabricating apatite crystals and ceramics

    DOEpatents

    Soules, Thomas F.; Schaffers, Kathleen I.; Tassano, Jr., John B.; Hollingsworth, Joel P.

    2013-09-10

    The present invention provides a method of crystallizing Yb:C-FAP [Yb.sup.3+:Ca.sub.5(PO.sub.4).sub.3F], by dissolving the Yb:C-FAP in an acidic solution, following by neutralizing the solution. The present invention also provides a method of forming crystalline Yb:C-FAP by dissolving the component ingredients in an acidic solution, followed by forming a supersaturated solution.

  3. Down-shifting emission of Yb3+ ions sensitized by broad charge transfer band of V-O and Yb-O in Ca2V2O7 phosphors

    NASA Astrophysics Data System (ADS)

    Feng, Zhongshan; Jiang, Sha; Luo, Xiaobing; Shen, Jun; Pang, Yu; Li, Li; Zhou, Xianju

    2016-12-01

    Yb3+ singly doped pyrovanadate Ca2V2O7 phosphors were prepared by conventional solid state reaction. The crystal structure of the powders was investigated by X-ray diffraction. The diffuse reflection spectrum, photoluminescence excitation, emission spectra were investigated. The intense near infrared down-shifting emission of Yb3+ ions were demonstrated upon excitation of ultraviolet (UV) photon in a wide range of 250-450 nm. The broad excitation band in UV is attributed to the overlap of Yb3+-O2- and V5+-O2- charge transfer band. With the combination of wide Yb-O charge transfer band, which is seldom reported to sensitize the down-shifting emission of Yb3+ ion, the spectral response of the spectral converting materials is greatly extended. The energy transfer process from V-O and Yb-O charge transfer band to Yb3+ ions and involved mechanism have been discussed.

  4. Impact of stoichiometry of Yb2Ti2O7 on its physical properties

    NASA Astrophysics Data System (ADS)

    Arpino, K. E.; Trump, B. A.; Scheie, A. O.; McQueen, T. M.; Koohpayeh, S. M.

    2017-03-01

    A series of Yb2 +xTi2 -xO7 -δ doped samples demonstrates the effects of off-stoichiometry on Yb2Ti2O7 's structure, properties, and magnetic ground state via x-ray diffraction, specific heat, and magnetization measurements. A stoichiometric single crystal of Yb2Ti2O7 grown by the traveling solvent floating zone technique (solvent = 30 wt % rutile TiO2 and 70 wt % Yb2Ti2O7 ) is characterized and evaluated in light of this series. Our data shows that upon positive x doping, the cubic lattice parameter a increases and the Curie-Weiss temperature θCW decreases. Heat capacity measurements of stoichiometric Yb2Ti2O7 samples exhibit a sharp, first-order peak at T =268 (4) mK that is suppressed in magnitude and temperature in samples doped off ideal stoichiometry. The full entropy recovered per Yb ion is 5.7 J K-1≈R ln2 . Our work establishes the effects of doping on Yb2Ti2O7 's physical properties, which provides further evidence indicating that previous crystals grown by the traditional floating zone method are doped off ideal stoichiometry. Additionally, we present how to grow high-quality colorless single crystals of Yb2Ti2O7 by the traveling solvent floating zone growth method.

  5. Large magneto (thermo) dielectric effect in multiferroic orthorhombic LuMnO3

    NASA Astrophysics Data System (ADS)

    Wang, L. J.; Chai, Y. S.; Feng, S. M.; Zhu, J. L.; Manivannan, N.; Jin, C. Q.; Gong, Z. Z.; Wang, X. H.; Li, L. T.

    2012-06-01

    We have investigated the relation between ferroelectric and magnetic orders of orthorhombic (o-) LuMnO3 ceramics. The increase of dielectric constant ɛ exceeds 82% near incommensurate to commensurate E-type antiferromagnetic (AFM) spin ordering transition temperature TL, reflecting a large magneto (thermo) dielectric response. Meanwhile, distinct anomalies and thermal hysteresis behavior are observed near this temperature in both temperature dependence of ɛ and specific heat Cp, indicating a strong coupling between FE and magnetic orders in o-LuMnO3. Comparing to o-HoMnO3, TmMnO3, and YbMnO3 with similar E-type AFM ground state, o-LuMnO3 has the largest magneto (thermo) dielectric effect

  6. High energy, single-polarized, single-transverse-mode, nanosecond pulses generated by a multi-stage Yb-doped photonic crystal fiber amplifier

    NASA Astrophysics Data System (ADS)

    Shen, Xinglai; Zhang, Haitao; Hao, He; Li, Dan; Li, Qinghua; Yan, Ping; Gong, Mali

    2015-06-01

    We report the construction of a cascaded fiber amplifier where a 40-μm-core-diameter photonic crystal fiber is utilized in the main amplifier stage. Single-transverse-mode, linearly-polarized, 7.5 ns pulses with 1.5 mJ energy, 123 kW peak power and 10 nm spectral bandwidth centered at 1062 nm are generated. To our knowledge, the pulse energy we obtain is the highest from 40-μm-core-diameter photonic crystal fibers, and also the highest for long pulses (>1 ns) with linear polarization and single transverse mode.

  7. Hexamer clusters in MeF2:Yb3+ (Me = Ca,Sr,Ba)

    NASA Astrophysics Data System (ADS)

    Chernyshev, V. A.; Nikiforov, A. E.; Nazemnikh, A. D.

    2011-10-01

    The electronic structure and g factors of simple impurity centers and hexamer ytterbium clusters in fluorites have been calculated in terms of the exchange charge model. Preliminarily, their local crystal structures have been calculated in the framework of the shell model with the inclusion of lattice distortions near the impurity. Crystal structure and g factors have been calculated of linear cluster Yb-F-Yb-F oriented along a trigonal axis in BaF2.

  8. Dielectric and Optical Properties of Epitaxial Rare-Earth Scandate Films and Their Crystallization Behavior

    SciTech Connect

    Christen, Hans M; Jellison Jr, Gerald Earle; Ohkubo, I.; HUANG, S.; Reeves, M. E.; Cicerrella, E.; Freeouf, J. L.; Jia, Y.; Schlom, D. G.

    2006-01-01

    Rare-earth scandates (ReScO{sub 3}, with Re = Y, La, Pr, Nd, Sm, Gd, Tb, Dy, Ho, Er, Tm, Yb, and Lu, i.e., the entire series for which the individual oxides are chemically stable in contact with Si) were deposited in a temperature-gradient pulsed laser deposition system onto LaAlO{sub 3} substrates. The crystallization temperature depends monotonically on the Re atomic number and the Goldschmidt tolerance factor, with crystallization temperatures as low as 650 C for LaScO{sub 3} and PrScO{sub 3}. The dielectric constants of the crystalline films K {approx} 30 (determined by microwave microscopy) are significantly larger than those of their amorphous counterparts. In combination with the large observed band gaps (E{sub g} > 5.5 eV, determined by ellipsometry), these results indicate the potential of these materials as high-K dielectrics for field-effect transistor applications.

  9. Mode-locked operation of a diode-pumped femtosecond Yb:SrF2 laser.

    PubMed

    Druon, F; Papadopoulos, D N; Boudeile, J; Hanna, M; Georges, P; Benayad, A; Camy, P; Doualan, J L; Ménard, V; Moncorgé, R

    2009-08-01

    Femtosecond mode-locked operation is demonstrated for the first time, to our knowledge, with a Yb:SrF(2) crystal. The shortest pulse duration is 143 fs for an average power of 450 mW. The highest average power is 620 mW for a pulse duration of 173 fs. Since Yb:SrF(2) corresponds to the longest-lifetime Yb-doped crystal with which the mode-locking operation has been achieved, a detailed analysis is carried out to characterize the quality of the solitonlike regime.

  10. Growth, structural, thermal, electrical and nonlinear optical properties of Yb3+ doped KTiOPO4

    NASA Astrophysics Data System (ADS)

    Sadhasivam, S.; Perumal, Rajesh Narayana; Ramasamy, P.

    2016-07-01

    The KTiOPO4:Yb (KTP:Yb) crystal has been grown by flux growth at high temperature (~ 1243-1223K). KTP:Yb crystallizes in the orthorhombic crystal system with Pna21 space group. Ytterbium presence was analyzed in the grown crystal by EDAX analysis. The existence of Ti3+ color center has been evaluated using electron paramagnetic spin resonance spectrum. The Raman spectroscopic techniques were used to study the effect of Yb3+ in KTP crystal. Thermal diffusivity, thermal conductivity and specific heat capacity of grown crystal were studied. At low frequency, the dielectric constant decreases sharply in the frequency region of 104 Hz. The electrical conductivity along the [001] is low (9.0435×10-7 S/cm) for 60 kHz at 300 K. The temperature dependent variation of electric conductivity was found for [010] and [001] of KTP:Yb. The effect of Yb3+ doping in second harmonic generation of KTP was studied.

  11. [K(2)CsYb(PO(4))(2)].

    PubMed

    Rghioui, Lotfi; el-Ammari, Lahcen; Benarafa, Larbi; Wignacourt, Jean Pierre

    2002-07-01

    The crystal structure of dipotassium caesium ytterbium bis(phosphate) is built up from regular independent PO(4) tetrahedra and YbO(6) octahedra sharing corners and arranged in layers. The structure is, in many respects, similar to that of glaserite.

  12. Effect of ytterbium concentration on cw Yb:YAG microchip laser performance at ambient temperature - Part II: Theoretical modeling

    NASA Astrophysics Data System (ADS)

    Dong, Jun; Shirakawa, A.; Ueda, K.-I.; Kaminskii, A. A.

    2007-11-01

    A theoretical model based on a quasi-four-level system is modified to investigate the effect of Yb concentration on performance of continuous-wave Yb:YAG microchip lasers by taking into account temperature-dependent thermal population distribution, temperature-dependent emission cross-section and concentration-dependent fluorescence lifetime, thermal loading, thermal conductivity, and thermal expansion coefficient. The local temperature rise in Yb:YAG crystal caused by the absorbed pump power plays an important role in the laser performance of Yb:YAG microchip lasers working at ambient temperature without actively cooling the sample. The output wavelengths dependent on output coupling, Yb concentration, and pump power level were analyzed quantitatively. The numerical simulation of Yb:YAG microchip lasers is in good agreement with experimental data. The optimized laser operation for Yb:YAG microchip lasers is proposed by varying the thickness and output coupling for different Yb concentrations. The effect of thermal lens, thermal deformation effect, and saturated inversion population distribution inside the Yb:YAG crystal on performance of heavy-doped Yb:YAG microchip lasers are also addressed.

  13. The MueLu Tutorial

    SciTech Connect

    Hu, Jonathan Joseph; Wiesner, Tobias A.; Prokopenko, Andrey; Gee, Michael

    2014-10-01

    The MueLu tutorial is written as a hands-on tutorial for MueLu, the next generation multigrid framework in Trilinos. It covers the whole spectrum from absolute beginners’ topics to expert level. Since the focus of this tutorial is on practical and technical aspects of multigrid methods in general and MueLu in particular, the reader is expected to have a basic understanding of multigrid methods and its general underlying concepts. Please refer to multigrid textbooks (e.g. [1]) for the theoretical background.

  14. Synthesis of NaYF4, NaLuF4 and NaGdF4-based upconversion nanocrystals with hydro (solvo) thermal methods.

    PubMed

    Yin, Dongguang; Song, Kailin; Ou, Yangjuan; Wang, Chengcheng; Liu, Bing; Wu, Minghong

    2013-06-01

    Serials of NaYF4, NaLuF4 and NaGdF4-based nanocrystals have been synthesized successfully by solvothermal and hydrothermal, respectively. The properties of the products were characterized and compared. The nanocrystals prepared by hydrothermal method exhibited uniform hexagonal phase and large size, while the nanocrystals prepared by solvothermal method displayed high upconversion luminescence (UCL) and small size. The UCL intensities of the nanocrystals prepared by solvothermal method were higher than that of nanocrystals from hydrothermal method. Whether using solvothermal or hydrothermal method, the UCL intensities of the nanocrystals were in the sequence (from strong to weak) of NaLuF4:Gd/Yb/Tm, NaLuF4:Yb/Tm, NaGdF4:Yb/Tm, NaYF4:Gd/Yb/Tm and NaYF4:Yb/Tm, respectively. This is the first time to systematically compare three kinds of host-based nanocrystals, which are prepared by two different approaches with various lanthanide ions doped. This work could provide new insight into fabrication of upconversion nanocrystals with intense UCL and controllable morphology and size via using suitable doping ions, host materials and efficient approaches.

  15. Scintillation properties of LuI 3:Ce

    NASA Astrophysics Data System (ADS)

    Glodo, J.; Shah, K. S.; Klugerman, M.; Wong, P.; Higgins, B.; Dorenbos, P.

    2005-01-01

    Lutetium iodide (LuI3) is a new addition to the family of Ce-doped lanthanide trihalide scintillating materials. Crystals of this material show hexagonal structure with density of 5.6 g/cm3 and have been grown by the Bridgman method. Under X-ray excitation this material exhibits broad, cerium based emission that peaks at 475 and 520 nm. The fastest and major component of scintillation time profile of LuI3:Ce emission decays with a 31 ns time constant. The light yield of LuI3:Ce for thin samples (∼0.2 mm) was estimated to be ∼50,000 photons/MeV.

  16. Synchrotron X-ray diffraction and Raman spectroscopy of Ln{sub 3}NbO{sub 7} (Ln=La, Pr, Nd, Sm-Lu) ceramics obtained by molten-salt synthesis

    SciTech Connect

    Siqueira, K.P.F.; Soares, J.C.; Granado, E.; Bittar, E.M.; Paula, A.M. de; Moreira, R.L.; Dias, A.

    2014-01-15

    Ln{sub 3}NbO{sub 7} (Ln=La, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, and Lu) ceramics were obtained by molten-salt synthesis and their structures were systematically investigated by synchrotron X-ray diffraction (SXRD), second harmonic generation (SHG) and Raman spectroscopy. It was observed that ceramics with the largest ionic radii (La, Pr, Nd) crystallized into the Pmcn space group, while the ceramics with intermediate ionic radii (Sm-Gd) exhibited a different crystal structure belonging to the Ccmm space group. For this last group of ceramics, this result was corroborated by SHG and Raman scattering and ruled out any possibility for the non-centrosymmetric C 222{sub 1} space group, solving a recent controversy in the literature. Finally, according to SXRD, Tb-Lu containing samples exhibited an average defect fluorite structure (Fm3{sup ¯}m space group). Nonetheless, broad scattering at forbidden Bragg reflections indicates the presence of short-range domains with lower symmetry. Vibrational spectroscopy showed the presence of six Raman-active modes, inconsistent with the average cubic fluorite structure, and in line with the existence of lower-symmetry nano-domains immersed in the average fluorite structure of these ceramics. - Graphical abstract: Raman spectrum for Sm{sub 3}NbO{sub 7} ceramics showing their 27 phonon modes adjusted through Lorentzian lines. According to synchrotron X-ray diffraction and Raman scattering, this material belongs to the space group Cmcm. Display Omitted - Highlights: • Ln{sub 3}NbO{sub 7} ceramics were obtained by molten-salt synthesis. • SXRD, SHG and Raman scattering confirmed orthorhombic and cubic structures. • Ccmm instead of C222{sub 1} is the correct structure for Sm–Gd ceramics. • Pmcn space group was confirmed for La-, Pr- and Nd-based ceramics. • For Tb–Lu ceramics, ordered domains of a pyrochlore structure were observed.

  17. Electronic Configuration of Yb Compounds

    SciTech Connect

    Temmerman, W.M.; Szotek, Z.; Svane, A.; Strange, P.; Winter, H.; Delin, A.; Johansson, B.; Eriksson, O.; Fast, L.; Wills, J.M.

    1999-11-01

    The total energy differences between divalent and trivalent configurations of Yb ions in a number of Yb compounds are studied. Two different band theoretical methods, which differ in the treatment of the localized f electrons, are used. The results show that in all Yb compounds the valence energy differences are equal to the energy needed to localize an f electron. These valence energy differences correlate with the number of f electrons hybridizing with the conduction bands in the trivalent configuration. For divalent YbS, the pressure induced f -electron delocalization implies an intermediate valency, as also indicated by experiment. {copyright} {ital 1999} {ital The American Physical Society }

  18. Crystal and electronic structures of CaAl{sub 2}Si{sub 2}-type rare-earth copper zinc phosphides RECuZnP{sub 2} (RE=Pr, Nd, Gd-Tm, Lu)

    SciTech Connect

    Blanchard, Peter E.R.; Stoyko, Stanislav S.; Cavell, Ronald G.; Mar, Arthur

    2011-01-15

    The quaternary rare-earth phosphides RECuZnP{sub 2} (RE=Pr, Nd, Gd-Tm, Lu) have been prepared by reaction of the elements at 900 {sup o}C, completing this versatile series which forms for nearly all RE metals. They adopt the trigonal CaAl{sub 2}Si{sub 2}-type structure (Pearson symbol hP5, space group P3-bar m1, Z=1), as confirmed by single-crystal X-ray diffraction analysis on ErCuZnP{sub 2} and powder X-ray diffraction analysis on the remaining members. The Cu and Zn atoms are assumed to be disordered over the single transition-metal site. Band structure calculations on a hypothetically ordered YCuZnP{sub 2} model suggest a semimetal, with a zero band gap between the valence and conduction bands. This electronic structure is supported by XPS valence band spectra for RECuZnP{sub 2} (RE=Gd-Er), in which the intensity drops off smoothly at the Fermi edge. The absence of a band gap permits the electron count to deviate from the precise value of 16 e{sup -} per formula unit, as demonstrated by the formation of a solid solution in GdCu{sub x}Zn{sub 2-x}P{sub 2} (1.0{<=}x{<=}1.3), while still retaining the CaAl{sub 2}Si{sub 2}-type structure. Because the Cu 2p XPS spectra indicate that the Cu atoms are always monovalent, the substitution of Cu for Zn leads to a decrease in electron count and a lowering of the Fermi level in the valence band. The magnetic susceptibility of RECuZnP{sub 2} (RE=Gd-Er), which obeys the Curie-Weiss law, confirms the presence of trivalent RE atoms. -- Graphical abstract: The absence of a band gap in the semimetallic quaternary rare-earth phosphides RECuZnP{sub 2} permits the formation of a solid solution such as GdCu{sub x}Zn{sub 2-x}P{sub 2} through hole-doping of the valence band. Display Omitted

  19. Powerful visible (530???770 nm) luminescence in Yb,Ho:GGG with IR diode pumping.

    PubMed

    Kir'yanov, Alexander; Aboites, V; Belovolov, A; Timoshechkin, M; Belovolov, M; Damzen, M; Minassian, A

    2002-08-12

    Powerful visible luminescence in a Gadolinium Gallium Garnet (GGG) crystal, co-activated with Yb3+ (~15 at.%) and Ho3+ (~0.1 at.%) ions, is investigated under CW laser diode pumping (lambda = 938 and 976 nm). The main visible emission band is observed in the green with its peak at lambda ~540 nm) and measured to be about 10% with respect to Yb3+ IR luminescence (lambda ~1000 nm). Red (lambda ~650 nm) and near-IR (lambda ~755 nm) emission bands are also observed but are weaker (about 3-5%). Analysis of the crystal absorption and luminescence spectra allows one to conclude that Yb3+ - Ho3+ stepwise up-conversion is the mechanism explaining the phenomenon. Ho3+ ions embedded in the crystal in small concentration are shown to form an effective reservoir for energy transferred from the excited Yb3+ subsystem and to be an efficient source of the visible emission.

  20. Green and red luminescence in co-precipitation synthesized Pr:LuAG nanophosphor

    SciTech Connect

    Kumar, S. Arun; Kumar, K. Ashok; Gunaseelan, M.; Senthilselvan, J.; Asokan, K.

    2016-05-06

    Pr:LuAG nanophosphor is an effective candidate in magnetic resonance imaging coupled positron emission tomography (MRI-PET) for medical imaging and scintillator applications. LuAG:Pr (0.05, 0.15 mol%) nanoscale ceramic powders were synthesized by co-precipitation method using urea as precipitant. Effect of antisite defect on structure and luminescence behavior was investigated. Pr:LuAG nanoceramic powders are found crystallized in cubic structure by high temperature calcination at 1400 °C and it shows antisite defect. HR-SEM analysis revealed spherically shaped Pr:LuAG nanoceramic particulate powders with ∼100 nm size. By the excitation at 450 nm, Pr:LuAG nanophosphor exhibit green to red luminescence in the wavelength range of 520 to 680 nm, which is originated from multiplet transition of Pr{sup 3+} ions.

  1. Dual nature of 3 d electrons in YbT 2 Zn 20 (T = Co; Fe) evidenced by electron spin resonance

    DOE PAGES

    Ivanshin, V. A.; Litvinova, T. O.; Gimranova, K.; ...

    2015-03-18

    The electron spin resonance experiments were carried out in the single crystals YbFe2Zn20. The observed spin dynamics is compared with that in YbCo2Zn20 and Yb2Co12P7 as well as with the data of inelastic neutron scattering and electronic band structure calculations. Our results provide direct evidence that 3d electrons are itinerant in YbFe2Zn20 and localized in YbCo2Zn20. Possible connection between spin paramagnetism of dense heavy fermion systems, quantum criticality effects, and ESR spectra is discussed.

  2. Implications of garnet resorption for the Lu-Hf garnet geochronometer: Makhevinekh Lake Pluton aureole, Labrador

    NASA Astrophysics Data System (ADS)

    Kelly, E. D.; Carlson, W. D.; Connelly, J.

    2009-12-01

    In the contact aureole of the Makhevinekh Lake Pluton (MLP), Labrador, garnet resorption caused redistribution of Lu and loss of Hf, creating spuriously young Lu-Hf ages. Resetting of the Lu-Hf system by contact metamorphic heating is not primarily responsible for progressively younger ages toward the MLP; instead, ages depend upon the degree of garnet resorption and the original core-to-rim Lu zoning. Garnet grew during granulite-facies regional metamorphism at 1850 Ma. At 1322 Ma, garnet rims were replaced by coronas of opx + crd during contact metamorphism. Garnet-rutile and garnet-ilmenite Lu-Hf geochronology using bulk garnet separates yields ages younging from 1878 ±22 Ma at 4025 m from the contact to 1397 ±8 Ma at 450 m from the contact. Toward the contact, garnet Lu/Hf ratios increase and garnet crystals are progressively more resorbed. Concentrations of Lu measured by LA-ICP-MS along radial traverses on central sections through relict garnets decrease gently away from the cores but rise steeply within 50-200 microns of the edge of the relict garnet. Enrichments of Lu in rims of relict garnets demonstrate strong partitioning of Lu into garnet during resorption and limited intracrystalline diffusion of Lu during contact metamorphism. Hf distributions could not be measured, but considering the strong incompatibility of Hf with garnet, it is likely that all Hf in resorbed portions of the garnets was lost from the crystals. We hypothesize that Lu-Hf ages in the aureole are controlled predominantly by retention of Lu and loss of Hf during garnet resorption. We tested this hypothesis with a simple numerical model in which we treat a population of garnets of uniform size with identical original Lu growth zoning. The model simulates: (1) Lu-Hf decay for a specified period before resorption; (2) retention of Lu and loss of Hf from the rim during instantaneous resorption; and (3) Lu-Hf decay during a specified period after resorption. We varied the volume fraction

  3. Cubic sub-20 nm NaLuF(4)-based upconversion nanophosphors for high-contrast bioimaging in different animal species.

    PubMed

    Yang, Tianshe; Sun, Yun; Liu, Qian; Feng, Wei; Yang, Pengyuan; Li, Fuyou

    2012-05-01

    A new upconversion luminescence (UCL) nanophosphors based on host matrix of cubic NaLuF(4) with bright luminescence have been synthesized by a solvothermal method, facilitate the nanocrystals potential candidates for imaging in vivo, especially large-animals. The sub-20 nm NaLuF(4) co-doped Yb(3+) and Er(3+) (Tm(3+)) showed about 10-fold stronger UCL emission than that of corresponding hexagonal NaYF(4)-based nanocrystals with a 20 nm diameter. Near-infrared to near-infrared (NIR-to-NIR) UCL emission of PAA-coated NaLuF(4):20%Yb,1%Tm (PAA-Lu(Tm)) can penetrate >1.5 cm tissue of pork with high contrast. Based on super-strong UCL emission and deep penetration, PAA-Lu(Tm) as optical bioprobe has been demonstrated by in vivo UCL imaging of a normal black mouse, even rabbit with excellent signal-to-noise ratio. Furthermore, such cubic NaLuF(4)-based nanophosphor was applied in lymph node imaging of live Kunming mouse with rich white fur. Copyright © 2012 Elsevier Ltd. All rights reserved.

  4. Scintillation and luminescence properties of Sm3+-activated Lu2O3-CaO-SiO2-B2O3 (LuCSB) scintillating glasses

    NASA Astrophysics Data System (ADS)

    Kirdsiri, K.; Kaewkhao, J.; Park, J. M.; Ha, D. H.

    2016-09-01

    Lutetium (Lu) is a high atomic number material and readily interacts with X-rays, which makes it a good scintillation material. In this work, Lu-glass scintillators from the series xSm2O3: 25Lu2 O3: 10SiO2: 10CaO: (55- x)B2O3 (LuCSB) were synthesized at 1500 ° C by using a simple melt quenching technique. The influence of the Sm3+ ion on their physical, optical, photo-, X-rayand proton-induced properties has been characterized. The amorphous nature of the samples was confirmed by using X-ray diffraction. The density and the molar volume were found to be increased at higher concentrations of Sm3+. The X-ray- and the proton-induced emission spectra of the Sm3+:LuCSB glasses showed an intense reddish-orange emission around 604 nm (4G5/2 → 6H7/2), which matched the photoluminescence (PL) emission spectrum well. Among the prepared glasses, the 1.0-mol% Sm3+ ion-activated LuCSB glass exhibited the highest value of the characteristic emission parameters. The X-ray-induced luminescence of the LuCSB glass was also compared with that of a commercial bismuth germinate Bi4Ge3O12 (BGO) crystal.

  5. Temperature influence on diode pumped Yb:GGAG laser

    NASA Astrophysics Data System (ADS)

    Veselský, Karel; Boháček, Pavel; Šulc, Jan; Jelínková, Helena; Trunda, Bohumil; Havlák, Lubomír.; Jurek, Karel; Nikl, Martin

    2017-05-01

    We present temperature influence (in range from 78 up to 400,K) on spectroscopic properties and laser performance of new Yb-doped mixed garnet Gd3GaxAl5-xO12 (Yb:GGAG). The sample was 2.68 mm thick plane-parallel face-polished Yb:GGAG single-crystal plate which was AR coated for pump (930 nm) and generated (1030 nm) laser radiation wavelength. The composition of sample was Gd3.098Yb0:0897Ga2:41Al2.41O12 (3 at % Yb/Gd). The Yb:GGAG crystal was mounted in temperature controlled copper holder of the liquid nitrogen cryostat. The 138 mm long semi-hemispherical laser resonator consisted of a flat pumping mirror (T > 90 % @ 930 nm, HR @ 1030 nm) placed inside cryostat, and a curved output coupler (r = 150 mm, R = 94.5 % @ 1030 nm) placed outside cryostat. For longitudinal pumping a fiber coupled laser diode was used. The diode was operating in the pulse regime (5 ms pulse length, 20 Hz repetition rate) at wavelength 928.5 nm. The absorption spectrum was measured for the temperatures from 78 to 400 K, and absorption lines narrowing was observed with temperature decrease. Zero-phonon line at 970 nm has width 1 nm (FWHM) at 100 K. The fluorescence intensity decay time was measured and it increased linearly with temperature from 864 μs @ 78 K to 881 μs @ 300 K. The temperature of active medium has strong influence mainly on laser threshold which was 5 times lower at 100 K than at 300 K, and on slope efficiency which was 3 times higher at 100 K than at 300 K.

  6. Design and characterization of Yb and Nd doped transparent ceramics for high power laser applications: recent advancements

    NASA Astrophysics Data System (ADS)

    Lapucci, A.; Vannini, M.; Ciofini, M.; Pirri, A.; Nikl, M.; Li, J.; Esposito, L.; Biasini, V.; Hostasa, J.; Goto, T.; Boulon, G.; Maksimov, R.; Gizzi, L.; Labate, L.; Toci, G.

    2017-01-01

    We report a review on our recent developments in Yttebium and Neodymium doped laser ceramics, along two main research lines. The first is the design and development of Yb:YAG ceramics with non uniform doping distribution, for the management of thermo-mechanical stresses and for the mitigation of ASE: layered structures have been produced by solid state reactive sintering, using different forming processes (spray drying and cold press of the homogenized powders, tape cast of the slurry); samples have been characterized and compared to FEM analysis. The second is the investigation of Lutetium based ceramics (such as mixed garnets LuYAG and Lu2O3); this interest is mainly motivated by the favorable thermal properties of these hosts under high doping. We recently obtained for the first time high efficiency laser emission from Yb doped LuYAG ceramics. The investigation on sesquioxides has been focused on Nddoped Lu2O3 ceramics, fabricated with the Spark Plasma Sintering method (SPS). We recently achieved the first laser emission above 1 W from Nd doped Lu2O3 ceramics fabricated by SPS.

  7. High pressure synthesis of a new phase of YbAg2: Structure, valence of Yb and properties

    DOE PAGES

    Tsvyashchenko, A. V.; Menushenkov, A. P.; Sidorov, V. A.; ...

    2015-08-05

    The new phase of YbAg2 was obtained using high-pressure and high-temperature reaction. YbAg2 crystallizes in the MgZn2 structure (the space group P63/mmc space group, No 194) with a = 5.68153(3) Å and c = 9.31995(7) Å and the unit cell volume V = 260.54(3) Å3. The XANES analysis showed that the valence state of Yb is +2.8. The low-temperature dependences of the electrical resistivity and magnetic susceptibility can be adequately described by a T2 term that supports the Fermi-liquid picture. Furthermore, the Kadowaki–Woods relation gives a low value of the degeneracy (N = 2).

  8. High pressure synthesis of a new phase of YbAg2: Structure, valence of Yb and properties

    SciTech Connect

    Tsvyashchenko, A. V.; Menushenkov, A. P.; Sidorov, V. A.; Petrova, A. E.; Fomicheva, L. N.; Chernysheva, O. V.; Lebed, Yu. B.; Axenov, S. N.; Bud’ko, S. L.; Sun, Liling; Zhao, Zhongxian

    2015-08-05

    The new phase of YbAg2 was obtained using high-pressure and high-temperature reaction. YbAg2 crystallizes in the MgZn2 structure (the space group P63/mmc space group, No 194) with a = 5.68153(3) Å and c = 9.31995(7) Å and the unit cell volume V = 260.54(3) Å3. The XANES analysis showed that the valence state of Yb is +2.8. The low-temperature dependences of the electrical resistivity and magnetic susceptibility can be adequately described by a T2 term that supports the Fermi-liquid picture. Furthermore, the Kadowaki–Woods relation gives a low value of the degeneracy (N = 2).

  9. Upconversion Nanophosphors Naluf4:Yb,Tm for Lymphatic Imaging In Vivo by Real-Time Upconversion Luminescence Imaging under Ambient Light and High-Resolution X-ray CT

    PubMed Central

    Sun, Yun; Peng, Juanjuan; Feng, Wei; Li, Fuyou

    2013-01-01

    Lanthanide upconversion nanophosphor (UCNP) has attracted increasing attention for potential applications in bioimaging due to its excellence in deep and high contrast imaging. To date, most upconversion imaging applications were demonstrated in dark surroundings without ambient light for higher signal-to-noise ratio, which hindered the application of optical imaging guided surgery. Herein, the new established NaLuF4-based UCNP (NaLuF4:Yb,Tm, ~17 nm) with bright upconversion emission around 800 nm as imaging signal was used to realize imaging under ambient light to provide more convenient for clinician. Moreover, due to the existance of heavy element lutetium (Lu) in the host lattice, the NaLuF4:Yb,Tm nanoparticles can also be used as an X-ray CT imaging agent to enhance the imaging depth and in vivo imaging resolution. PMID:23650481

  10. Upconversion nanophosphors Naluf₄:Yb,Tm for lymphatic imaging in vivo by real-time upconversion luminescence imaging under ambient light and high-resolution X-ray CT.

    PubMed

    Sun, Yun; Peng, Juanjuan; Feng, Wei; Li, Fuyou

    2013-01-01

    Lanthanide upconversion nanophosphor (UCNP) has attracted increasing attention for potential applications in bioimaging due to its excellence in deep and high contrast imaging. To date, most upconversion imaging applications were demonstrated in dark surroundings without ambient light for higher signal-to-noise ratio, which hindered the application of optical imaging guided surgery. Herein, the new established NaLuF₄-based UCNP (NaLuF₄:Yb,Tm, ~17 nm) with bright upconversion emission around 800 nm as imaging signal was used to realize imaging under ambient light to provide more convenient for clinician. Moreover, due to the existance of heavy element lutetium (Lu) in the host lattice, the NaLuF₄:Yb,Tm nanoparticles can also be used as an X-ray CT imaging agent to enhance the imaging depth and in vivo imaging resolution.

  11. Multiband electronic transport in α-Yb1₋xSrx AlB4 [ x = 0, 0.19(3)] single crystals

    SciTech Connect

    Ryu, Hyejin; Abeykoon, Milinda; Bozin, Emil; Matsumoto, Yosuke; Nakatsuji, S.; Petrovic, C.

    2016-08-19

    Here we report on the evidence for the multiband electronic transport in α- YbAlB4 and α-Yb0.81(2)Sr0.19(3)AlB4. Multiband transport reveals itself below 10 K in both compounds via Hall effect measurements, whereas anisotropic magnetic ground state sets in below 3 K in α-Yb0.81(2)Sr0.19(3)AlB4. Our results show that Sr2+ substitution enhances conductivity, but does not change the quasiparticle mass of bands induced by heavy fermion hybridization.

  12. Multiband electronic transport in α-Yb1₋xSrx AlB4 [ x = 0, 0.19(3)] single crystals

    SciTech Connect

    Ryu, Hyejin; Abeykoon, Milinda; Bozin, Emil; Matsumoto, Yosuke; Nakatsuji, S.; Petrovic, C.

    2016-08-19

    Here we report on the evidence for the multiband electronic transport in α- YbAlB4 and α-Yb0.81(2)Sr0.19(3)AlB4. Multiband transport reveals itself below 10 K in both compounds via Hall effect measurements, whereas anisotropic magnetic ground state sets in below 3 K in α-Yb0.81(2)Sr0.19(3)AlB4. Our results show that Sr2+ substitution enhances conductivity, but does not change the quasiparticle mass of bands induced by heavy fermion hybridization.

  13. Organization of the human LU gene and molecular basis of the Lu(a)/Lu(b) blood group polymorphism.

    PubMed

    El Nemer, W; Rahuel, C; Colin, Y; Gane, P; Cartron, J P; Le Van Kim, C

    1997-06-15

    The Lutheran (Lu) blood group antigens and the B-cell adhesion molecule (B-CAM) epithelial cancer antigen are carried by recently cloned integral glycoproteins that belong to the Ig superfamily. We have previously shown that the Lu and B-CAM antigens are encoded by the same gene, LU, and that alternative splicing of the primary transcript most likely accounts for the presence of both antigens on two isoforms that differ by the length of their cytoplasmic tails. In the present report, we isolated the human LU gene by cloning a 20-kb HindIII fragment from Lu(a - b+) genomic DNA. The LU gene is organized into 15 exons distributed over 12.5 kb. Alternative splicing of intron 13 generates the 2.5- and 4.0-kb transcript spliceoforms encoding the long tail and the short tail Lu polypeptides, respectively. Sequencing of the major mRNA species (2.5 kb) amplified from human bone marrow, kidney, placenta, and skeletal muscle did not suggest the presence of tissue-specific Lu glycoprotein isoforms. The same transcription initiation point, located 22 bp upstream from the initiation codon, was characterized in several tissues. In agreement with the wide tissue distribution of the Lu messengers, the GC-rich proximal 5' flanking region of the LU gene does not contain TATA or CAAT boxes, but includes several potential binding sites for the ubiquitous Sp1 transcription factor. In addition, the distal 5' region, encompassing nucleotides -673 to -764, contains clustered binding sequences for the GATA, CACCC, and Ets transcription factors. Analysis of the coding sequences amplified from genomic DNA of Lu(a + b-) or Lu(a - b+) donors showed a single nucleotide change in exon 3 (A229G) that correlates with an Aci I restriction site polymorphism and results in a His77Arg amino-acid substitution. Polymerase chain reaction/restriction fragment length polymorphism analysis indicated that the A229G mutation is associated with the Lu(a)/Lu(b) blood group polymorphism. When expressed in Chinese

  14. Efficient operation of a diode-pumped Yb:NaY(WO(4))(2) laser.

    PubMed

    Xie, G Q; Tang, D Y; Zhang, H J; Wang, J Y; Qian, L J

    2008-02-04

    An efficient diode-pumped Yb:NaY(WO(4))(2) (Yb:NYW) disordered crystal laser has been experimentally demonstrated for the fist time. The Yb:NYW crystal has a peak absorption cross section of 1.09 x 10(-20) cm(2) at 972 nm and emission cross section of 1.24 x 10(-20) cm(2) at 1010 nm. Under an absorbed pump power of 11.7 W, the Yb:NYW laser generated an average output power as high as 4.1 W, with a slope efficiency of 45%. It was found that the laser always operated in a self-pulsing mode, and the laser spectrum showed random jumps with time. The mechanism of self-pulsing in the laser was also investigated.

  15. Anisotropic intermediate valence in Yb2M3Ga9 (M = Rh, Ir)

    SciTech Connect

    Christianson, A.D.; Lawrence, J.M.; Lobos, A.M.; Aligia, A.A.; Bauer, E.D.; Moreno, N.O.; Booth, C.H.; Goremychkin, E.A.; Sarrao, J.L.; Thompson, J.D.; Batista, C.D.; Trouw, F.R.; Hehlen, M.P.

    2005-04-26

    The intermediate valence compounds Yb{sub 2}M{sub 3}Ga{sub 9} (M = Rh, Ir) exhibit an anisotropic magnetic susceptibility. We report measurements of the temperature dependence of the 4f occupation number, n{sub f}(T), for Yb{sub 2}M{sub 3}Ga{sub 9} as well as the magnetic inelastic neutron scattering spectrum S{sub mag}({Delta}E) at 12 and 300 K for Yb{sub 2}Rh{sub 3}Ga{sub 9}. Both n{sub f}(T) and S{sub mag}({Delta}E) were calculated for the Anderson impurity model with crystal field terms within an approach based on the non-crossing approximation. These results corroborate the importance of crystal field effects in these materials; they also suggest that Anderson lattice effects are important to the physics of Yb{sub 2}M{sub 3}Ga{sub 9}.

  16. Diytterbium(II) lithium indium(III) digermanide, Yb2LiInGe2

    PubMed Central

    You, Tae-Soo; Bobev, Svilen

    2010-01-01

    The title compound, Yb2LiInGe2, a new ordered quaternary inter­metallic phase, crystallizes with the ortho­rhom­bic Ca2LiInGe2 type (Pearson code oP24). The crystal structure contains six crystallographically unique sites in the asymmetric unit, all in special positions with site symmetry .m.. The structure is complex and based on [InGe4] tetra­hedra, which share corners in two directions, forming layers parallel to (001). Yb atoms fill square-pyramidal (Yb1) and octa­hedral (Yb2) inter­stices between the [InGe4/2] layers, while the small Li+ atoms fill tetra­hedral sites. PMID:21578989

  17. Lattice dynamics of LuPO{sub 4}

    SciTech Connect

    Nipko, J.C. |; Loong, C.-K.; Loewenhaupt, M.; Reichardt, W.; Braden, M.; Boatner, L.A.

    1996-06-01

    Lutetium orthophosphate is an important nonmagnetic host material for rare-earth-activated luminescence applications. We have measured the LuPO{sub 4} phonon density of states and dispersion curves along the [{xi}00],[{xi}{xi}0], and [00{xi}] symmetry directions by neutron spectroscopy using polycrystalline and single-crystal samples. A quantitative analysis of the neutron results was carried out using a lattice-dynamical shell model.

  18. Spectroscopy and continuous-wave diode-pumped laser action of Yb3+:YVO4.

    PubMed

    Kisel, V E; Troshin, A E; Tolstik, N A; Shcherbitsky, V G; Kuleshov, N V; Matrosov, V N; Matrosova, T A; Kupchenko, M I

    2004-11-01

    The growth, spectroscopic properties, and laser performance of Yb:YVO4 crystal with laser diode pumping are reported. A peak absorption cross section of 7.4 x 10(-20) cm2 at 985 nm, a radiative lifetime of 0.25 ms, and a stimulated-emission cross section of 1.25 x 10(-20) cm2 at 1008 nm for pi polarization were determined for the Yb3+ ions in YVO4. Continuous-wave laser action of Yb:YVO4 at 1020-1027 nm was demonstrated with an output power of 610 mW and a slope efficiency of 49%.

  19. Yb:FAP and related materials, laser gain medium comprising same, and laser systems using same

    DOEpatents

    Krupke, William F.; Payne, Stephen A.; Chase, Lloyd L.; Smith, Larry K.

    1994-01-01

    An ytterbium doped laser material remarkably superior to all others, including Yb:YAG, comprises Ytterbium doped apatite (Yb:Ca.sub.5 (PO.sub.4).sub.3 F) or Yb:FAP, or ytterbium doped crystals that are structurally related to FAP. The new laser material is used in laser systems pumped by diode pump sources having an output near 0.905 microns or 0.98 microns, such as InGaAs and AlInGaAs, or other narrowband pump sources near 0.905 microns or 0.98 microns. The laser systems are operated in either the conventional or ground state depletion mode.

  20. Intermediate valence behavior of Yb2Ni12P7 studied by using 31P NMR

    NASA Astrophysics Data System (ADS)

    Koyama, T.; Sugiura, K.; Ueda, K.; Mito, T.; Kohara, T.; Satoh, R.; Tsuchiya, K.; Nakano, T.; Takeda, N.

    2013-08-01

    The Yb-based heavy-fermion compound Yb2Ni12P7 with a hexagonal Zr2Fe12P7-type crystal structure was investigated by using the 31P nuclear magnetic resonance (NMR) technique. The complicated NMR line changes its shape gradually with decreasing temperature, implying the presence of some Knight shift components. The temperature dependences of the Knight shift and the nuclear spin-lattice relaxation rate 1/ T 1 suggest the delocalization of 4 f electrons.

  1. High-peak-power tunable laser operation of Yb:SrF2.

    PubMed

    Siebold, Mathias; Hein, Joachim; Kaluza, Malte Christoph; Uecker, Reinhard

    2007-07-01

    Growth, spectroscopic properties, and laser performance of Yb:SrF(2) crystals have been investigated. In spatial multimode operation of a diode-pumped Yb:SrF(2) laser a slope efficiency of 46% was measured. 180W output power with high beam quality at a pulse duration of 1.5ms was achieved by installing a mode cleaning aperture. A maximum average output power of 270mW and a tuning range of 73nm was observed.

  2. Resonantly pumped room temperature Ho:LuVO₄ laser.

    PubMed

    Yao, B Q; Cui, Z; Duan, X M; Du, Y Q; Han, L; Shen, Y J

    2014-11-01

    Spectroscopic characterization of a Ho:LuVO4 crystal grown by the Czochralski method has been performed, including the absorption and emission spectra. We demonstrate a 2 μm room temperature Ho:LuVO4 laser, resonantly pumped by a 1.94 μm Tm:YAP laser. By use of an output coupler with T=10% transmission, the Ho:LuVO4 laser generated continuous-wave output power of 2.5 W at 2074.18 nm, with a beam quality factor of Mx2=My2=1.3, for a total incident pump power of 19.4 W. The slope efficiency with respect to the pump power was 17.6%, and the optical-to-optical efficiency was 12.9%. Moreover, we obtained a Ho:LuVO4 laser that operated at 2073.77 and 2055.27 nm, by using different output couplers with transmissions of T=15 and 30%.

  3. Two new layered oxohalides in the system Cu-Yb-Te-O-Cl

    NASA Astrophysics Data System (ADS)

    Zhang, Dong; Johnsson, Mats; Kremer, Reinhard K.

    2010-04-01

    Two complex lanthanide(III) transition metal(II) tellurium(IV) oxyhalides, Cu 3Yb 2(TeO 3) 4Cl 4 and Cu 3Yb 3(TeO 3) 4Cl 6 have been synthesized and the crystal structures were determined by single-crystal X-ray diffraction. Both compounds are layered with only weak connections in between the layers. The layers are made up of [YbO 8], [TeO 3] and [CuO xCl y] polyhedra. In both compounds the strong Lewis acid cations Yb 3+ and Te 4+ only form bonds to oxygen while Cu 2+ form bonds to both oxygen and chlorine. This leads the Cl - ions to be expelled from the bonding volumes of the crystal structures and protrude from the layers. Magnetic susceptibility measurements were performed on a powder sample of Cu 3Yb 2(TeO 3) 4Cl 4. The Curie-Weiss law found at low temperatures indicates a Curie-Weiss temperature of ca. -5(1) K. However, indication for long-range magnetic ordering could not be observed down to 1.87 K. The two new phases are to the best of our knowledge the first containing all three of Cu, Yb and Te.

  4. Kinetic control of structural and magnetic states in LuBaCo4O7.

    SciTech Connect

    Avci, S.; Chmaissem, O.; Zheng, H.; Huq, A.; Khalyavin, D.; Stephens, P.; Suchomel, M.; Manuel, P.; Mitchell, J.

    2012-01-01

    The RBaCo{sub 4}O{sub 7} (R = Ca, Y, Tb, Ho, Tm, Yb, Lu) compounds provide a novel topology for studying the competition between triangular geometry and magnetic order. Here, we report the structural and magnetic behavior of the Lu member of this series via neutron and synchrotron x-ray diffraction, magnetization, and resistivity measurements. We determined sequential phase transitions and a strong competition between a stable and a metastable low-temperature state that critically depends on controlled cooling rates and the associated heat removal kinetics. No evidence for long-range ordered magnetism was detected by neutron diffraction at any temperature. However, very slow spin dynamics are evidenced by time-dependent neutron diffraction measurements and can be explained by several competing magnetic phases with incommensurate short-range correlations coexisting in this material.

  5. Synthesis of metastable rare-earth-iron mixed oxide with the hexagonal crystal structure

    NASA Astrophysics Data System (ADS)

    Nishimura, Tatsuya; Hosokawa, Saburo; Masuda, Yuichi; Wada, Kenji; Inoue, Masashi

    2013-01-01

    Rare-earth-iron mixed oxides with the rare earth/iron ratio=1 have either orthorhombic (o-REFeO3) or hexagonal (h-REFeO3) structure. h-REFeO3 is a metastable phase and the synthesis of h-REFeO3 is usually difficult. In this work, the crystallization process of the precursors obtained by co-precipitation and Pechini methods was investigated in detail to synthesize h-REFeO3. It was found that the crystallization from amorphous to hexagonal phase and the phase transition from hexagonal to orthorhombic phase occurred at a similar temperature range for rare earth elements with small ionic radii (Er-Lu, Y). For both co-precipitation and Pechini methods, single-phase h-REFeO3 was obtained by shortening the heating time during calcination process. The hexagonal-to-orthorhombic phase transition took place by a nucleation growth mechanism and vermicular morphology of the thus-formed orthorhombic phase was observed. The hexagonal YbFeO3 had higher catalytic activity for C3H8 combustion than orthorhombic YbFeO3.

  6. Yb9+xCuMg4-x (x = 0.034): A κ-Phase Formed by Lanthanoids.

    PubMed

    De Negri, Serena; Romaka, Vitaliy; Solokha, Pavlo; Saccone, Adriana; Giester, Gerald; Michor, Herwig; Rogl, Peter F

    2016-08-15

    Atom order in the crystal structures of Yb2Cu2-xMg (x = 0.17; Mo2FeB2-type; P4/mbm; a = 0.75592(2) nm; c = 0.40282(1) nm) and Yb9+xCuMg4-x (x = 0.034; Hf9Mo4B-type; P63/mmc; a = 1.0169(5) nm; c = 1.0290(5) nm) was determined from powder and X-ray single-crystal counter data analyses supported by electron probe microanalyses. Among the group of the so-called κ-phases, Yb9+xCuMg4-x is the first representative formed by a lanthanoid element. The structure of this κ-phase can be viewed as a typical network of corner-connected empty Yb6-octahedra, which encompass Yb6Mg6-icosahedra (filled by a mix of Mg/Yb atoms) and Yb6-trigonal prisms centered by Cu atoms to complete the three-dimensional metal framework. From another point of view, the same structure is considered as built from infinite polyicosahedral columns of Yb9Mg4 composition with Cu atoms located in trigonal prismatic interstices, highlighting similarities with other Yb-rich Yb-Cu-Mg phases. Density functional theory (DFT) calculations classify Yb9CuMg4 as a polar intermetallic. Metallic-like behavior is inferred from the Sommerfeld constant, γ = 49.2 mJ/mol·K(2), derived from the electronic density of states, calculated at the Fermi level. DFT integration of the f-density of states indicates almost completely filled f-states, revealing 13.6 and 13.7 electrons in the valence band for Yb1 and Yb2 atoms, respectively, close to the Yb(2+) ground state ((1)S0) for both Yb atoms. Magnetic susceptibility data recorded on the same compound are consistent with a nonmagnetic divalent Yb(2+) state. Temperature-dependent heat capacity data display a metallic behavior characterized by a small Sommerfeld constant γ = 64.8 mJ/mol·K(2) and a rather low Debye temperature ΘD = 140 K as typical for soft materials.

  7. Fiber-laser pumped actively Q-switched Er:LuYAG laser at 1648 nm

    NASA Astrophysics Data System (ADS)

    Yang, X. F.; Wang, Y.; Zhao, T.; Zhu, H. Y.; Shen, D. Y.

    2016-02-01

    We demonstrated an acousto-optic Q-switched 1648 nm Er:LuYAG laser resonantly pumped by a cladding-pumped Er,Yb fiber laser at 1532 nm. Stable Q-switching operation was obtained with the pulse repetition rate (PRR) varying from 200 Hz to 10 kHz. At PRR of 200 Hz, the laser yielded Q-switched pulses with 3.3 mJ pulse energy and 65 ns pulse duration, corresponding to a peak power of 50.7 kW for 10.4 W of incident pump power.

  8. Disorder-Sensitive Superconductivity and Bonding Network in the Iron-Silicide Superconductor Lu2Fe3Si5

    NASA Astrophysics Data System (ADS)

    Watanabe, Tadataka; Okuyama, Hiroaki; Takase, Kouichi; Takano, Yoshiki; Yoshida, Fumiko; Moriyoshi, Chikako; Kuroiwa, Yoshihiro

    2010-03-01

    Iron silicide superconductor Lu2Fe3Si5 exhibits relatively high Tc = 6.0 K among Fe-based substances. Recent specific heat, penetration depth, and thermal conductivity measurements have provided evidences for the multigap superconductivity. We have studied non-magnetic and magnetic impurity effects on superconductivity in Lu2Fe3Si5 by investigating Tc variations in non-magnetic (Lu1-xScx)2Fe3Si5, (Lu1-xYx)2Fe3Si5 and magnetic (Lu1-xDyx)2Fe3Si5. Small amount of non-magnetic impurities (Sc and Y) on the Lu-site rapidly depresses Tc in accordance with the increase in the residual resistivity. Such a disorder-sensitive superconductivity strongly suggests the sign reversal of the superconducting order parameter. Lu2Fe3Si5 has a complicated crystal structure compared to other multigap superconductors such as MgB2 and iron pnictides. Thus it is important to map out the accurate bonding network in the crystal structure for the better understanding of the electronic structure. We have observed the charge density distribution of Lu2Fe3Si5 by analyzing the synchrotron radiation powder diffraction data using the maximum entropy method/Rietveld method.

  9. FUNDAMENTAL AREAS OF PHENOMENOLOGY (INCLUDING APPLICATIONS): Cooperative Quantum Cutting of Nano-Crystalline BaF2:Tb3+, Yb3+ in Oxyfluoride Glass Ceramics

    NASA Astrophysics Data System (ADS)

    Chen, Jing-Xin; Ye, Song; Wang, Xi; Qiu, Jian-Rong

    2008-06-01

    We report on cooperative quantum cutting in Tb3+-Yb3+ codoped glass ceramics. Precipitation of BaF2 nano-crystals is confirmed by XRD and HRTEM analysis. Near-infrared emission due to transition of Yb3+ ions under 485 nm excitation indicates cooperative energy transfer from Tb3+ to Yb3+. The quantum efficiency of this process reaches 145%. The realization of quantum cutting in glass ceramics may have promising applications in solar cells.

  10. Tuning hexagonal NaYbF4 nanocrystals down to sub-10 nm for enhanced photon upconversion.

    PubMed

    Shi, Ruikai; Ling, Xincan; Li, Xiaona; Zhang, Lu; Lu, Min; Xie, Xiaoji; Huang, Ling; Huang, Wei

    2017-09-08

    Enhancing upconversion emission is critical for small-sized lanthanide doped upconversion nanocrystals. A promising way is increasing the doping concentration of excitation energy absorbers, the Yb(3+) sensitizer. However, it is still a challenge to obtain small-sized hexagonal NaLnF4 (Ln: lanthanide) upconversion nanocrystals with a high Yb(3+) concentration due to the fast growth of NaYbF4 crystals, which hinders their applications particularly in biology. We here demonstrate a highly repeatable and controllable method for tuning the size of hexagonal NaYbF4 nanocrystals, down to ∼7 nm, without the assistance of additional impurity doping. By monitoring the reaction process, we found that ultrasmall hexagonal NaYbF4 nanocrystals were formed through an in situ transformation of their cubic counterparts. We observed an enhanced upconversion emission of NaYbF4:Tm nanocrystals when compared to that of NaYbF4:Y/Tm nanocrystals with less Yb(3+) doping. After coating a thin layer of a NaYF4 shell on NaYbF4:Tm nanocrystals, a ∼100 times upconversion emission enhancement with over 800 times stronger emission in the ultraviolet and blue ranges was observed. This versatile method, together with the strong upconversion emission of the as-prepared ultrasmall nanocrystals, should facilitate the future applications of upconversion nanocrystals.

  11. Correlation between magnon and magnetic symmetries of hexagonal RMnO3 (R = Er, Ho, Lu)

    NASA Astrophysics Data System (ADS)

    Nguyen, Thi Minh Hien; Nguyen, Thi Huyen; Chen, Xiang-Bai; Park, Yeonju; Jung, Young Mee; Lee, D.; Noh, T. W.; Cheong, Sang-Wook; Yang, In-Sang

    2016-11-01

    The correlation between the magnon scattering and the magnetic symmetries of hexagonal RMnO3 (R = Er, Ho) thin films and LuMnO3 single crystal was studied through the 2D Correlation Spectroscopy (2D COS) and Perturbation-Correlation Moving Window 2D (PCMW2D) Correlation Spectroscopy which were performed on the temperature-dependent Raman spectra of RMnO3 (R = Er, Ho, Lu). From the Raman spectra, we observed much stronger intensity and more asymmetrical magnon peak in LuMnO3 single crystal than in ErMnO3 and HoMnO3 thin films. While the ratio between magnon and phonon's linewidth of LuMnO3 and HoMnO3 display an anomalous behavior, that ratio of ErMnO3 is almost stable. The result from PCMW2D also supports these results. In addition, our 2D COS analysis showed that there are more overlap peaks in broad four-spin flipping magnon peak in LuMnO3 than that in ErMnO3 and HoMnO3. The differences of hexagonal RMnO3 (R = Er, Ho, Lu) in magnon scattering are very similar to the actual differences of the magnetic symmetries of these compounds. Therefore, we suggest that the magnon scattering of hexagonal RMnO3 is strongly correlated with the magnetic symmetries of these materials.

  12. Consequences of meta-stable (177m)Lu admixture in (177)Lu for patient dosimetry.

    PubMed

    Konijnenberg, Mark W

    2015-01-01

    Lutetium-177 ((177)Lu) is a rare earth metal in the lanthanides series which decays by beta emission with a half life of 6.647 days to three excited states and the ground state of (177)Hf. When (177)Lu is produced by neutron capture in (176)Lu, inevitably an admixture is formed of the long-lived isomer (177)mLu. As its half-life of 160.4 days is so much longer than that of (177)Lu, concerns are raised on its possible enhancement in radiation dose to the patient treated with (177)Lu-DOTA-octreotate. This report evaluates this possible enhancement of the absorbed dose, based on the published pharmacokinetic profile of (177)Lu-DOTA-octreotate and assuming an admixture of 1 kBq (177)mLu /MBq (177)Lu (0.1%).

  13. Search for compounds of the NaBaR(BO{sub 3}){sub 2} family (R = La, Nd, Gd, and Yb) and the new NaBaYb(BO{sub 3}){sub 2} orthoborate

    SciTech Connect

    Svetlyakova, T. N. Kokh, A. E.; Kononova, N. G.; Fedorov, P. P.; Rashchenko, S. V.; Maillard, A.

    2013-01-15

    A search for compounds of the NaBaR(BO{sub 3}){sub 2} composition (where R = La{sup 3+}, Nd{sup 3+}, Gd{sup 3+}, or Yb{sup 3+}) is performed by solid state synthesis and spontaneous crystallization. A new compound, NaBaYb(BO{sub 3}){sub 2}, is found in this series. It crystallizes in space group R3{sup -} and belongs to the family of sublayer complex orthoborates with isolated BO{sub 3} groups NaBaR(BO{sub 3}){sub 2} (R = Y, Sc, and Yb). Theoretical X-ray powder diffraction patterns of NaBaY(BO{sub 3}){sub 2}, NaBaSc(BO{sub 3}){sub 2}, and NaBaYb(BO{sub 3}){sub 2} are calculated based on single-crystal data.

  14. High-light-output scintillator for photodiode readout: LuI3:Ce3+

    NASA Astrophysics Data System (ADS)

    Birowosuto, M. D.; Dorenbos, P.; van Eijk, C. W. E.; Krämer, K. W.; Güdel, H. U.

    2006-06-01

    In this paper, we investigated the scintillation properties of LuI3:Ce3+. Radioluminescence, light output, energy resolution, and γ-scintillation decay are reported. We find an extremely high light output of 98 000+/-10 000 photons/MeV. LuI3:Ce3+ also gives a very high electron-hole (e-h) pair response when it is coupled with an avalanche photodiode (APD) (92 000+/-9000 e-h pairs/MeV). With an APD, a best energy resolution (full width at half maximum over the peak position) of 3.3%+/-0.3% for 662 keV γ quanta is observed. A combination of an extremely high light output and a good energy resolution makes LuI3:Ce3+ an ideal scintillator for radiation sensor applications. Some drawbacks due to the hygroscopicity and the difficult growth of LuI3:Ce3+ crystals are also discussed.

  15. Growth and luminescent properties of Lu2SiO5 and Lu2SiO5:Ce single crystalline films

    NASA Astrophysics Data System (ADS)

    Zorenko, Yu; Nikl, M.; Gorbenko, V.; Mares, J. A.; Savchyn, V.; Voznyak, T.; Solsky, I.; Grynyov, B.; Sidletskiy, O.; Kurtsev, D.; Beitlerova, A.; Kucerkova, R.

    2010-11-01

    Single crystalline films (SCF) of Lu2SiO5 (LSO) and Lu2SiO5:Ce (LSO:Ce) silicates with thickness of 2.5-21 μm were crystallised by liquid phase epitaxy method onto undoped LSO substrates from melt-solution based on PbO-B2O3 flux. The luminescence and scintillation properties of LSO and LSO:Ce SCFs were compared with the properties of a reference LSO:Ce and LYSO:Ce crystals. The light yield (LY) of LSO and LSO:Ce SCF reaches up 30 % and 145 %, respectively, of that of a reference LSO:Ce crystal under excitation by α-particles of 241Am source (5.5 MeV). We found that the luminescence spectrum of LSO:Ce SCF is red-shifted with respect to the spectrum of a reference LSO:Ce crystal. Differences in luminescence properties of LSO:Ce SCF and single crystal are explained by the different distribution of Ce3+ over the Lu1 and Lu2 positions of LSO host and are also due to Pb2+ contamination in the former.

  16. Conversion coefficient measurements of 176Lu using ICEBall

    NASA Astrophysics Data System (ADS)

    Battaglia, Anthony A.

    We have studied the multipolarites of several transitions in the nucleus 176Lu. The synthesis of 176Lu in stellar environments is through the slow (s-) neutron capture process. The s-process is responsible for the creation of 50% of the heavy elements and 15-20 nuclei in the s-process are s-process branching points. Branching points determine if the synthesis path will beta-decay or neutron capture. The branching point 176 Lu is only produced via the s-process only and has both a long-lived ground state (K = 7--) of 37.6 Gy and a short-lived isomeric state (K = 0--) at 3.6 h. There is no direct decay to both the isomer and ground state due to selection rules. However, an intermediate state was found at 839 keV in the K = 4-- band and another intermediate state in the K = 4+ band at 709 keV which communicate to both the isomer and ground state. The communication to both the isomer and ground state through the intermediate states affects the final abundances of 176Lu in stellar environments which is sensitive to temperature. The experiment was performed at the University of Notre Dame Nuclear Science Laboratory (NSL) using a 176Yb(p,n) reaction at 7.75 MeV. Gamma-gamma and gamma-electron coincidences were measured for conversion coefficients using the Internal Conversion Electron Ball (ICEBall) array and two HPGe detectors (109% relative efficiency of a 3"x 3" NaI detector at 1332 keV). ICEBall was upgraded at the NSL for an improved efficiency from 6%-15% over 4. A total of 40 conversion cofficcients were measured and 35 multipolarities wer assigned. 17 new conversion coefficients were measured and the corresponding multipolarities were assigned. Levels and spin assignments in both the K = 4+ band and K = 4-- band were verified in the intermediate states that are important for establishing a thermal equilibrium in the s-process.

  17. Transparent Oxyfluoride Nano-Glass-Ceramics Doped with Pr3+ and Pr3+-Yb3+ for NIR Emission

    NASA Astrophysics Data System (ADS)

    Gorni, Giulio; Cosci, Alessandro; Pelli, Stefano; Pascual, Laura; Durán, Alicia; Pascual, M. J.

    2016-12-01

    Pr3+-Yb3+ co-doped oxyfluoride glasses and glass-ceramics (GC) containing LaF3 nanocrystals have been prepared to obtain NIR emission of Yb3+ ions upon Pr3+ excitation in the blue region of the visible spectrum. Two different compositions have been tested 0.1-0.5 Pr-Yb and 0.5-1 Pr-Yb, in addition to Pr3+ singly doped samples. The crystallization mechanism of the nano-glass-ceramics was studied by DTA revealing that it occurs from a constant number of nuclei, the crystal growth being limited by diffusion. HR-TEM demonstrated that phase separation acts as precursor for LaF3 crystallization and a detailed analysis of the chemical composition (EDXS) revealed the enrichment in RE3+ ions inside the initial phase separated droplets, from which the LaF3 crystals are formed. The RE3+ ions incorporation inside LaF3 crystals was also proved by photoluminescence measurements showing Stark splitting of the RE3+ ions energy levels in the glass-ceramic samples. Lifetimes measurements showed the existence of a better energy transfer process between Pr3+ and Yb3+ ions in the glass-ceramics compared to the as made glass, and the highest value of energy transfer efficiency is 59% and the highest theoretical quantum efficiency is 159%, obtained for glass-ceramics GC0.1-0.5 Pr-Yb treated at 620 ºC-40 h.

  18. Investigation of nanostructured Lu2O3:Tb

    NASA Astrophysics Data System (ADS)

    Zych, E.; Deren, Przemyslaw J.; Strek, Wieslaw; Meijerink, Andries; Domagala, K.; Mielcarek, W.

    2001-04-01

    Nano structured Lu2O3, both plane and doped with Tb, was prepared utilizing a combustion technique. The best crystallity of the products can be obtained initiating the reaction within 560-700 $DEGC range of temperature. Tb easily enters the nano scaled host lattice both as Tb3+ and Tb4+. The former gives rise to a typical green emission of the ion, while the later introduces a broad-band visible absorption, due to charge transfer transitions. The green emission of Tb3+ from a raw material may be radically increased by after- preparation heat-treatment. Undoped material gives rise to a blue emission, which disappears when Tb content with respect to Lu reaches 0.0001% or higher level.

  19. Downshifting by energy transfer in Eu3+/Yb3+ codoped Ba4La6(SiO4)6O glass ceramics

    NASA Astrophysics Data System (ADS)

    Zhang, W. J.; Li, X. B.; Wu, L. J.; Yu, Y. Y.; Wang, X. Z.; Liu, S. Q.; Wang, Z.; Wang, W. C.; Liu, Y.

    2017-03-01

    We report on an efficient near-infrared downshifting in Eu3+/Yb3+ codoped glass ceramics containing Ba4La6(SiO4)6O crystals. The structural and luminescence properties were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), static and dynamic photoemission and excitation spectroscopy. After crystallization, the doping ions are found to be selectively incorporated into the precipitated oxyapatite crystals on La3+ sites, contributing to the remarkably enhanced visible emission of Eu3+ under 394 nm excitation. The Eu3+/Yb3+ codoped glass ceramics additionally exhibits efficient near-infrared luminescence of Yb3+ around 1000 nm upon photon excitation of Eu3+ within the 300-550 nm range. The reduced visible emission and decay time of 5D0 state with Yb3+ codoping further confirm the energy transfer from Eu3+ to Yb3+, which is promoted due to the shortened distance between Eu3+ and Yb3+ within crystals. The maximum energy transfer efficiency is evaluated to be 61%. It is revealed that energy transfer process occurs predominantly through the cross relaxation of Eu3+(5D0) + Yb3+(2F7/2) → Eu3+(7F6) + Yb3+(7F5/2).

  20. Structure and phase composition of nanocrystalline Ce{sub 1-x}Lu{sub x}O{sub 2-y}

    SciTech Connect

    Malecka, Malgorzata A.; Kepinski, Leszek Maczka, Miroslaw

    2008-09-15

    The microstructure and phase stability of nanocrystalline mixed oxide Lu{sub x}Ce{sub 1-x}O{sub 2-y} (x=0-1) are described. Nano-sized (3-4 nm) oxide particles were prepared by the reverse microemulsion method. Morphological and structural changes upon heat treatment in an oxidizing atmosphere were studied by transmission electron microscopy (TEM), X-ray diffraction (XRD), Raman and Yb{sup 3+} emission spectroscopy, the latter ion being present as an impurity in the Lu{sub 2}O{sub 3} starting material. Up to 950 deg. C, the samples were single phase, with structure changing smoothly with Lu content from fluorite type (F) to bixbyite type (C). For the samples heated at 1100 deg. C phase separation into coexisting F- and C-type structures was observed for 0.35Lu strongly hinders the crystallite growth of ceria during heat treatment at 800 and 950 deg. C. - Graphical abstract: Phase separation in nanocrystalline Ce{sub 1-x}Lu{sub x}O{sub 2-y} mixed oxide heated in air at 1100 deg. C.