Erbium System Research Articles

Microstructural Master Alloys Features of Aluminum–Erbium System

Aluminum master alloys with rare earth metals are widely studied by many scientists around the world, but research on the production of Al-Er master alloys is still limited. The purpose of this work is to study the microstructure parameters of aluminum-erbium master alloys obtained by metallothermic reduction of salt mixtures containing erbium oxide or fluoride. The structural features were investigated by optical and scanning electron microscopy, and the dependence of the microhardness of the eutectic and solid solution fields of obtained master alloys on the content of erbium in the master alloy was determined. Studies have shown that master alloys obtained by metallothermic reduction of erbium compounds from chloride–fluoride melts are characterized by a uniform distribution of Al3Er intermetallic compounds in the volume of double eutectic [(Al) + Al3Er] and have a strong grain refinement effect. The analysis of the microstructure showed that the structure of the master alloys varies depending on the content of erbium. When the content of erbium in the master alloy is up to 6 wt.%, the eutectic structure is preserved. When the content of erbium in the master alloy is 8 wt.% or more, the structure becomes a solid solution with individual inclusions of various shapes and intermetallic compounds.

100-W-level single-mode ytterbium-free erbium fiber laser.

We report on an ytterbium-free, erbium-doped single-mode all-fiber laser reaching a record output power of 107 W at 1598 nm, with a slope efficiency of 38.6% according to the absorbed pump power at 981 nm. The erbium-doped gain fiber, co-doped with cerium, aluminum, and phosphorus, was fabricated in-house with adjusted doping concentrations to reduce erbium ions clustering, thereby increasing efficiency while keeping the numerical aperture low to ensure a single-mode laser operation. The addition of cerium co-dopant in the core glass of an erbium system is used for the first time, to the best of our knowledge, in order to adjust the fiber's numerical aperture without increasing the erbium concentration. Numerical modeling, validated by the experimental results, demonstrates that adding aluminum and phosphorus at high concentration mitigates erbium ions clustering, with an estimated erbium paired ions of only 5.0% in the reported gain fiber.

3.42 µm lasing in heavily-erbium-doped fluoride fibers.

In this paper, we investigate laser emission at 3.4μm in heavily-erbium-doped fluoride fibers using dual-wavelength pumping. To this extent, a monolithic 7 mol% erbium-doped fluoride fiber laser bounded by intracore fiber Bragg gratings at 3.42 μm is used to demonstrate a record efficiency of 38.6 % with respect to the 1976 nm pump. Through numerical modeling, we show that similar laser performances at 3.4 μm can be expected in fluoride fibers with erbium concentrations ranging between 1 - 7 mol%, although power scaling should rely on lightly-doped fibers to mitigate the heat load. Moreover, this work studies transverse mode-beating of the 1976 nm core pump and its role in the generation of a periodic luminescent grating and in the trapping of excitation in the metastable energy levels of the erbium system. Finally, we also report on the bistability of the 3.42 μm output power of the 7 mol% erbium-doped fluoride fiber laser.

Analytical interactomic potential for a molybdenum–erbium system

Analytical interatomic potentials of a molybdenum–erbium (Mo–Er) system are developed based on a Tersoff–Brenner-type form. The potentials well describes the bulk and defect properties of bcc Mo, including lattice parameter, cohesive energy, elastic constants, formation energies of point defects, surface energies and melting point. The adsorption behavior of Er on a Mo (1 1 0) surface is studied using ab initio calculations based on the density functional theory, which is used to fit the interatomic potential of a Mo–Er interaction. The growth mechanism of the Er film on a Mo substrate is investigated using the present potentials. The simulation results show that the microstructures and morphologies of Er films are sensitive to substrate temperatures. Columnar grains of hexagonal close-packed Er parallel to a Mo (1 1 0) surface are observed and the grain sizes increase with increasing substrate temperature.

Efficient carrier-envelope offset frequency stabilization through gain modulation via stimulated emission

A novel scheme for intracavity control of the carrier-envelope offset (CEO) frequency of a 100 MHz mode-locked Er:Yb:glass diode-pumped solid-state laser (DPSSL) based on the modulation of the laser gain via stimulated emission of the excited Er(3+) ions is demonstrated. This method allows us to bypass the ytterbium system few-kHz low-pass filter in the f(CEO) stabilization loop and thus to push the phase lock bandwidth up to a limit close to the relaxation oscillations frequency of the erbium system. A phase lock bandwidth above 70 kHz has been achieved with the fully stabilized laser, leading to an integrated phase noise [1 Hz-1 MHz] of 120 mrad.

Trends in the cation distribution in the structures of the compounds forming in the Ln2O3-GeO2-P2O5 systems

The cationic networks in the structures of the initial oxides and all binary and ternary compounds forming in the Ln2O3-GeO2-P2O5 systems have been studied. In the phase diagrams of the Nd2O3-GeO2-P2O5 and Er2O3-GeO2-P2O5 systems, the regions of the structural influence of individual compounds with topologically identical cationic networks—anisotropic (A), combined (C), and isotropic (I)—are united into common areas. The A: C: I area ratio is 1: 1: 1 in the neodymium system and 1.7: 1: 3.4 in the erbium system.

ChemInform Abstract: Thermodynamics of Gold-Erbium Alloys.

Abstract Galvanic cells with CaF 2 as solid electrolytes were used to obtain the thermodynamic properties of the gold–erbium system between 973 and 1073 K. A complete set of thermodynamic data was obtained for the gold-rich solid solution and for the intermetallic compounds Au 4 Er, Au 3 Er, Au 2 Er, AuEr and AuEr 2 . The relative partial excess Gibbs energy of erbium at infinite dilution was determined to be −257 kJ/mol at 1073 K. Electronic and elastic effects are discussed in order to account for the pronounced deviations from ideality.

Analysis of heat generation and thermal lensing in erbium 3-μm lasers

The influence of energy-transfer upconversion (ETU) between neighboring ions in the upper and lower laser levels of erbium 3-μm continuous-wave lasers on heat generation and thermal lensing is investigated. It is shown that the multiphonon relaxations following each ETU process generate significant heat dissipation in the crystal. This undesired effect is an unavoidable consequence of the efficient energy recycling by ETU in erbium 3-μm crystal lasers, but is further enhanced under nonlasing conditions. Similar mechanisms may affect future erbium 3-μm fiber lasers. In a three-dimensional finite-element calculation, excitation densities, upconversion rates, heat generation, temperature profiles, and thermal lensing are calculated for a LiYF <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">4</sub> :Er/sup 3+/ 3-μm laser. In the chosen example, the fraction of the absorbed pump power converted to heat is 40% under lasing and 72% under nonlasing conditions. The heat generation in a LiYF <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">4</sub> :Er/sup 3+/ 3-μm laser is 1.7 and the thermal-lens power up to 2.2 times larger than in a LiYF <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">4</sub> :Nd/sup 3+/ 1-μm laser under equivalent pump conditions, thus, also putting a higher risk of rod fracture on the erbium system.

Thermodynamics of gold–erbium alloys

Galvanic cells with CaF 2 as solid electrolytes were used to obtain the thermodynamic properties of the gold–erbium system between 973 and 1073 K. A complete set of thermodynamic data was obtained for the gold-rich solid solution and for the intermetallic compounds Au 4Er, Au 3Er, Au 2Er, AuEr and AuEr 2. The relative partial excess Gibbs energy of erbium at infinite dilution was determined to be −257 kJ/mol at 1073 K. Electronic and elastic effects are discussed in order to account for the pronounced deviations from ideality.

Clustering effects on double energy transfer in heavily ytterbium–erbium-codoped silica fibers

We study clustering effects in heavily ytterbium–erbium-codoped silica fibers. We demonstrate that the fraction of both ions found in clusters can exceed 50% in such fibers. A clustering effect is at the origin of an efficient double energy transfer process that generates a green fluorescence. An original method, based on a dynamic analysis of the ytterbium–erbium system, permits determination of the intracluster transfer rates involved, which are found to be high enough to compensate for the weak metastability of the erbium intermediate level.

Reaction of carbon with lanthanide silicides III: The Gd 5Si 3C and Ho 5Si 3C systems

The reaction of carbon with Gd 5Si 3 and Ho 5Si 3 was studied by arc melting the alloys with carbon and comparing the resultant phases with those identified previously in the Er 5Si 3 system. Ordering in the structure detected at x = 0.5 and x = 0.95 in Ln 5Si 3C x in both these systems is identical with that detected in the erbium system. Lower metal volatility in the gadolinium preparations produces single-phase systems more readily, but above x = 0.5 the carbide Gd 15C 19 is present in small amounts up to x = 0.95. Results for hardness, hydrolysis product distribution and X-ray and metallographic examination are presented.

Neutron Spectrum Measurements in a Homogeneous Erbium System and Erbium Cross Sections

Neutron Spectrum Measurements in a Homogeneous Erbium System and Erbium Cross Sections

Neutron Spectrum Measurements in a Homogeneous Erbium System and Erbium Cross Sections

Careful measurements and calculations of the neutron spectrum in an aqueous solution of erbium nitrate are described. The validity of the infinite medium calculation is scrutinizingly studied. As a...