Single crystals fiber technology design. Where we are today?

International audienceBecause of its performed mechanical, physical and optical properties, today single crystal fiber shape (SCFS) can be used for a large wide of application. As a function of the needed, it can be used as active or passive element in the component. The potential of single crystal fiber is extremely high. Intensive research has been devoted to design and optimize the technology process, but the increased technological requirements require continuous improvements at all stages of the fiber design: Fiber processing (growth fiber machine), starting raw materials, crucibles, growth direction, thermal gradient, gas atmosphere, fibers polishing, dopants segregation, packaging … This is demonstrated by the successful fiber pulling from the melt of more than 1 m length of sapphire, YAG and LuAG with performed properties

Discussion on the purity and the crystallization of CZTS compound

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

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Microstructure and crystallography of Al2O3–Y3Al5O12–ZrO2 ternary eutectic oxide grown by the micropulling down technique

International audienceThe directional solidification of Al2O3-YAG-ZrO2 eutectic ceramic by a micro pulling down (mu-PD) technique is investigated. The effect of the pulling rate (0.1-1 mm min(-1)) on the crystallography and the microstructure is discussed. This tel eutectic system has a Chinese script microstructure and the eutectic spacing lambda, depends On the pulling rate nu following the law: lambda = 6.5 nu(-1/2) where lambda is in pm and nu in mu m/s as derived from the Jackson-Hunt model. With the lower pulling rates, all phases are oriented with the direction parallel to the growth direction; however other orientations appear at the higher pulling rates. The Cr3+ ions R-lines emission in the sapphire phase in the ternary eutectic composite is measured to estimate the stress in the alumina phase which is also shown to depend on the pulling rate. (c) 2015 Elsevier B.V. All rights reserved

Growth, spectroscopy and lasing of the Yb-doped monoclinic Gd2SiO5 in the prospect of hydrogen laser cooling with Lyman-alpha radiation

International audienceWe have grown good optical quality 10% Yb-doped Gd2SiO5 monocrystal by the Czochralski technique. The Yb segregation coefficient was measured to be 0.747. In agreement with the monoclinic symmetry of the host, the Yb fluorescence extrema were found to deviate from the Nm and Ng principal axes and a fourth spectroscopic parameter representing the rotation of the fluorescence distribution was introduced for a full description. Diode pumped laser operation at Brewster incidence was demonstrated to be significantly more efficient if the lasing propagation corresponds to the maximum fluorescence inside the crystal. We obtained a laser emission tunable between 1079 and 1100 nm, showing that our crystal is the best choice for the application to the production of QCW Lyman-α radiation by resonant four-wave-mixing in mercury vapor

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

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Modeling of dopant segregation in sapphire single crystal fibre growth by Micro-Pulling-Down method

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Growth and characterization of Ca(2-x)Ae(x)Al(2)SiO(7) (Ae = Sr, Ba) piezoelectric single crystals

International audienceWe report the effects of Sr or Ba substitution on the crystal growth and electrical and mechanical properties of Ca2Al2SiO7 (CAS) piezoelectric single crystals, which are suitable for use in high-temperature pressure sensors. Ba was scarcely incorporated in the crystal lattice of CAS. Strontium-substituted CAS single crystal with a nominal chemical composition Ca0.75Sr1.25Al2SiO7 (CSAS125) was grown by the Czochralski method. Although the piezoelectric modulus d′31 of CSAS125 is a bit lower than that of the CAS crystal, the rupture strength of the (XYt)45° rotation cut substrate of CSAS125 crystal was 170 MPa, which was 1.2 times higher than that of CAS crystal. By considering the rupture strength and the apparent piezoelectric d*31 coefficient calculated for the crystal rotation cut of CAS crystal, the CSAS125 crystal substrate with a rotation cut of (XYt)25° was found to indicate a rupture strength of 220 MPa and a piezoelectric d′31 coefficient of approximately 2 pC/N