Extraction and stripping of ytterbium (III) from H2SO4 medium by Cyanex 923

The extraction and stripping of ytterbium (III) from sulfuric acid medium using Cyanex 923 in heptane solution was investigated. The effects of extractant concentration, pH and sulfate ion as well as stripping agents, acidity and temperature on the extraction and stripping were studied. The equilibrium constants and thermodynamic parameters, such as Delta H (10.76 kJ(.)mol(-1)), Delta G (-79.26 kJ(.)mol(-1)) and Delta S (292.41 J(.)K(-1.)mol(-1)), were calculated. The extraction mechanism and the complex species extracted were determined by slope analysis and FrIR spectra. Furthermore, it was found that the extraction of Yb (III) from sulfuric acid medium by Cyanex 923 increased with pH, concentration of SO42-, HSO4-, and extractant concentration, and approximately a quantitative extraction of Yb (III) was achieved at an equilibrium pH near 3.0, and the extracted complex was YbSO4(HSO4)(.)2Cyanex923((o)).

Synthesis of substituted indenyl lanthanide chloride and molecular structure of [(C5H9C9H6)(2)Yb(mu-Cl)(2)Li(Et2O)(2)]

Reaction of anhydrous ytterbium trichlorides with 2 equiv. of cyclopentylindenyl lithium in THF solution, followed by removal of the solvent MO. crystallization of the product from diethyl ether, affords a crystal complex of the composition (C5H9C9H6)(2)Yb(mu-Cl)(2)Li(Et2O)(2). Crystallographic analysis shows that the ytterbium coordinated by two cyclopentylindenyl rings and lithium surrounded by two ether molecules are bridged by the two chlorine atoms and Yb, U and two chlorine atoms form a plane.

SYNTHESES AND X-RAY STRUCTURES OF BIS(T-BUTYLCYCLOPENTADIENYL)LANTHANIDE CHLORIDE COMPLEXES [(BU(T)CP)2LNCL]2 (LN = PR, GD, ER)

Reaction of lanthanide trichlorides with two equivalents of sodium t-butylcyclopentadienide in THF gave rise to the bis(t-butylcyclopentadienyl)lanthanide chloride complexes [(Bu(t)Cp)2LnCl]2 (Ln = Pr, Gd, Er), which were characterized by elemental analysis, IR and H-1 NMR spectroscopy. In addition, the crystal structures of [(ButCp)2PrCl]2 (1) and [(ButCp)2GdCl]2 (2) were determined by single crystal X-ray diffraction at room temperature. The coordination number for Pr3+ and Gd3+ is 8 and the bond lengths Pr-Cl and Gd-Cl are 2.864(2) and 2.771(3) angstrom, respectively. The structural studies showed the complexes to have C2h symmetry.

SYNTHESES OF BIS(TERT-BUTYLCYCLOPENTADIENYL)LANTHANOID CHLORIDE COMPLEXES AND CRYSTAL-STRUCTURES OF BIS(TERT-BUTYLCYCLOPENTADIENYL)CHLORO(BISTETRAHYDROFURAN)-PRASEODYMIUM AND BIS(TERT-BUTYLCYCLOPENTADIENYL)-CHLOROTETRAHYDROFURANYTTERBIUM

Reaction of lanthanoid trichloride with two equivalents of sodium t-butylcyclopentadienide in tetrahydrofuran affords bis(t-butylcyclopentadienyl)lanthanoid chloride complexes (t-BuCp)2LnCl. nTHF (Ln = Pr, Nd, n = 2; Ln = Gd, Yb, n = 1). The compound (t-BuCp)2PrCl.2THF (1) crystallizes from THF in monoclinic space group P2(1)/c with unit cell dimensions a = 15.080(3), b = 8.855(2), c = 21.196(5) angstrom, beta = 110.34(2)degrees, V = 2653.9 angstrom-3 and D(calcd) = 1.41 g/cm3 for Z = 4. The central metal Pr is coordinated to two t-BuCp ring centroids, one chlorine atom and two THF forming a distorted trigonal bipyramid. The crystal of (t-BuCp)2YbCl.THF (2) belongs to the monoclinic crystal system, space group P2(1)/n with a = 7.726(1), b = 12.554(2), c = 23.200(6) angstrom, beta = 97.77(2)degrees, V = 2229.56 angstrom-3, D(calcd) = 1.50 g/cm3 and Z = 4. The t-BuCp ring centroids, the chlorine atom and the oxygen atom of the THF describe a distorted tetrahedron around the central ion of ytterbium.

Wavefront measurement of double-clad pulsed ytterbium fiber laser

Because of high efficiencies, compact structure, and excellent heat dissipation, high-power fiber lasers are extremely useful for applications such as cutting, welding, precision drilling, trimming, sensing, optical transmitter, material processing, micromachining, and so on. However, the wavefront of the double clad fiber laser doped with ytterbium is still unknown. In this paper, wavefront of a fiber laser is measured and the traditional Hartmann-shack wavefront sensing method is adopted. We measured a double clad fiber laser doped with ytterbium which produces pulse wave output at infrared wavelength. The wavefront shape and contour are reconstructed and the result shows that wavefront is slightly focused and not an ideal plane wavefront. Wavefront measurement of fiber laser will be useful to improving the lasers' performance and developing the coherent technique for its applications.

A four-passed ytterbium-doped fiber amplifier

In this paper, a four-passed ytterbium-doped fiber amplifier (YDFA) is discussed. The gain and the pump and the signal light propagation characteristics of the four-passed YDFA are described. It is found that, while using a shorter length of the fiber, a four-passed fiber amplifier can realize the same output power as a single-pass fiber amplifier, and, for the same fiber lengths, a four-passed fiber amplifier offers a significantly higher power than its single-pass counterpart. (C) 2006 Elsevier Ltd. All rights reserved.

A study of a Q-switched double-clad ytterbium-doped fiber laser with amplifying effect

A high repetition rate ytterbium-doped double-clad (YDDC) fiber laser with amplifying effect is described by using acousto-optic modulator. The characteristic of Q-switched pulses are studied with accurate control of opening gate time of modulator. The stable Q-switched pulses with tens of nanoseconds width can be observed at high repetition rate varied from 50 kHz to 500 kHz using this laser. The stable operation area of the Q-switched fiber laser is discussed and the analysis results agree well with that of the experiment. (c) 2007 Elsevier B.V. All rights reserved.

Effect of chloride ions' introduction on structural, thermal stability, and spectroscopic properties in Yb3+Er3+-codoped germanate-bismuth-lead glasses

Yb3+Er3+-codoped chloride-modified germanate-bismuth-lead glasses have been synthesized by the conventional melting and quenching method. Structural and thermal stability properties have been obtained on the basis of the Raman spectra and differential thermal analysis, which indicate that the PbCl2 addition has an important influence on the phonon density of states, maximum phonon energy, and thermal stability of host glasses. The Judd-Ofelt intensity parameters and quantum efficiencies were calculated on the basis of the Judd-Ofelt theory and lifetime measurements. For the 1.53 mu m emission band, the full widths at the half-maximum increase and peak wavelengths are blueshifted with increasing PbCl2 content. Moreover, the effect of the PbCl2 addition on the phonon density of states, OH- content, and upconversion luminescence has been discussed and evaluated. Our results reveal that, with increasing PbCl2 content, the decrease of phonon density and OH- content contributes more to the enhanced upconversion emissions than that of maximum phonon energy. (c) 2005 Optical Society of America

Fluorescence lifetime increasing with F- ions into ytterbium-doped germanium-lead-tellurite glasses

The effects of F- ions in a germanium-lead-tellurite glass system oil the spectral and potential laser properties of the Yb3+ are investigated. The absorption spectra, lifetimes, the emission cross-sections and the minimum pump intensities of the glass system with and without F- ions have been measured and calculated. The results show that the fluorescence lifetime and the minimum pump intensity of Yb3+ ions increase evidently, which indicates that germanium lead-oxyfluoride tellurite glass is a promising laser host matrix for high power generation. FT-IR spectra were used to analyse the effect of F- ions on OH- groups in this glass system. Analysis demonstrates that addition of fluoride removes the OH- groups and results in improvement of fluorescence lifetime of Yb3+.

Intense upconversion luminescence in ytterbium-sensitized thulium-doped novel oxychloride bismuth-germanium glass

Structural and up-conversion fluorescence properties in ytterbium-sensitized thulium-doped novel oxychloride bismuth-germanium glass have been studied. The structure of novel bismuth-germanium glass was investigated by peak-deconvolution of Raman spectrum, and the structural information was obtained from the peak wave numbers. The Raman spectrum investigation indicates that PbCl2 plays an important role in the formation of glass network, and has an important influence on the up-conversion luminescence. Intense blue and weak red emissions centered at 477 and 650 mn, corresponding to the transitions 1G(4) -> H-3(6) and (1)G(4) -> H-3(4), respectively, were observed at room temperature. The possible up-conversion mechanisms are discussed and estimated. This novel oxychloride bismuth-germanium glass with low maximum phonon energy (similar to 730 cm(-1)) can be used as potential host material for up-conversion lasers. (c) 2005 Elsevier Ltd. All rights reserved.

Green and red upconversion luminescence in ytterbium-sensitized erbrium-doped novel lead-free germanium bismuth lanthanum glass

Structural and infrared-to-visible upconversion fluorescence properties in ytterbium-sensitized erbrium-doped novel lead-free germanium bismuth-lanthanum glass have been studied. The structure of lead-free germanium-bismuth-lanthanum glass was investigated by peak-deconvolution of Raman spectrum, and the structural information was obtained from the peak wavenumbers. Intense green and red emissions centered at 525, 546, and 657 nm, corresponding to the transitions 2H(11/2) -> I-4(15/2), S-4(3/2) -> I-4(15/2), and F-4(9/2) -> I-4(15/2), respectively, were observed at room temperature. The quadratic dependence of the 525, 546, and 657 nm emissions on excitation power indicates that a two-photon absorption process occurs under 975 nm excitation. This novel lead-free germanium-bismuth-lanthanum glass with low maximum phonon energy (similar to 751 cm(-1)) can be used as potential host material for upconversion lasers. (c) 2005 Published by Elsevier B.V.

Comparative investigation of up-conversion luminescence in Tm3+-doped oxide-chloride germanate and tellurite glasses

Tm3+-doped oxide-chloride germanate and tellurite glasses have been synthesized by conventional melting method. Intense up-conversion luminescence emissions were simultaneously observed at room temperature in these glasses. The possible up-conversion mechanisms are discussed and estimated. However, in these Tm3+-doped glasses, tellurite glass showed weaker up-conversion emissions than germanate glass, which is inconsistent with the prediction from the difference of maximum phonon energy between tellurite and germanate glasses. In this paper, Raman spectroscopy was employed to investigate the origin of the difference in up-conversion luminescence in the two glasses. Our results confirm that, besides the maximum phonon energy, the phonon density of host glasses is also an important factor in determining the up-conversion efficiency. (c) 2005 Elsevier Ltd. All rights reserved.

Up-conversion luminescence analysis in ytterbium-sensitized erbium-doped oxide-halide tellurite and germanate-niobic-lead glasses

Ytterbium-sensitized erbium-doped oxide-halide tellurite and germanate-niobic-lead glasses have been synthesized by conventional melting method. Intense green and red emissions centered at 525, 546 and 657 nm, corresponding to the transitions H-2(11/2) -> I-4(15/2), S-4(3/2) -> I-4(15/2) and F-4(9/2) -> I-4(15/2), respectively, were simultaneously observed at room temperature in these glasses. The quadratic dependence of the 525, 546 and 657 nm emissions on excitation power indicates that a two-photon absorption process occurs. Tellurite glass showed a weaker up-conversion emission than germanate-niobic-lead glass, which is inconsistent with the prediction from the difference of maximum phonon energy between tellurite and germanate-mobic-lead glasses. In this paper, Raman spectroscopy was employed to investigate the origin of the difference in up-conversion luminescence in the two glasses. Compared with phonon side-band spectroscopy, Raman spectroscopy extracts more information including both phonon energy and phonon density. Our results reveal that the phonon density and the maximum phonon energy of host glasses are both important factors in determining the up-conversion efficiency. (c) 2005 Elsevier B.V. All rights reserved.

Intense upconversion luminescence in ytterbium-sensitized thullum-doped oxychloride germanate glass

Structural and upconversion fluorescence properties in ytterbium-sensitized thulium-doped oxychloride germanate glass have been studied. The structure of oxychloride germanate glass was investigated by peak-deconvolution of Raman spectrum, and the structural information was obtained from the peak wavenumbers. The Raman spectrum investigation indicates that PbCl2 plays an important role in the formation of glass network, and has an important influence on the upconversion luminescence. Intense blue and weak red emissions centered at 477 and 650 nm, corresponding to the transitions (1)G(4) ->(3) H-6 and (1)G ->H-3(4), respectively, were observed at room temperature. The possible upconversion mechanisms are discussed and estimated. Intense upconversion luminescence indicates that oxychloride germanate glass can be used as potential host material for upconversion lasers. (c) 2004 Elsevier B.V. All rights reserved.