Spectra and energy levels of Yb3+ ions in CaF2 transparent ceramics (original) (raw)
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Influence of some impurities on the emission properties of CaF2:YbF3 crystals
2015
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).
Fabrication and Property of Yb:CaF2 Laser Ceramics from Co-precipitated Nanopowders
Journal of Inorganic Materials
Transparent ytterbium doped calcium fluoride ceramics (Yb:CaF 2) were successfully fabricated by vacuum sintering and hot pressing post-treatment from coprecipitated powders. In-line transmittance of 5at% Yb:CaF 2 transparent ceramics fabricated by pre-sintering at 600 ℃ for 1 h and hot pressing post-treatment at 700 ℃ for 2 h, reaches 92.0% at the wavelength of 1200 nm. Microstructure, spectroscopic characteristics and laser performance of the ceramics were measured and discussed. The sample shows a homogeneous microstructure with average grain size of 360 nm. Furthermore, the absorption cross section at 977 nm and the emission cross section at the 1030 nm of the ceramics are calculated to 0.39×10-20 cm 2 and 0.26×10-20 cm 2 , respectively. Finally, the laser behavior was tested, finding a maximum output power of 0.9 W while the highest slope efficiency was 23.6%.
Influence of Various Impurities on the Optical Properties of YbF3-Doped CaF2 Crystals
Acta Physica Polonica A, 2007
Calcium fluoride crystals doped with YbF3 and co-doped with LiF and NaF were grown using the vertical Bridgman method. Several of rare-earth ions (such as Eu, Sm, Ho, Tm, and Yb) can be stabilized in the divalent state in the CaF2. The change of valence was attained by various methods. The optical absorption spectra reveal the characteristic absorption bands of the Yb 3+ and Yb 2+ ions. This means that the developed crystal growth process achieves a good Yb 3+ to Yb 2+ conversion in the as-grown crystals. The influence of other impurities, such as Na + or Li + , on the absorption and emission spectrum of YbF 3 -doped CaF 2 was studied. The Li + and Na + ions drastically decrease the absorption coefficient of the Yb 2+ ions in the UV band and the emission intensity by excitation in 230 nm.
Optical spectroscopy of Yb2+ ions in YbF3-doped CaF2 crystals
Journal of Crystal Growth, 2008
Transparent colorless Ca 1Àx Yb x F 2+x (x ¼ 0.0007-0.016) crystals were grown using the vertical Bridgman technique. In order to obtain efficient Yb 3+ -Yb 2+ conversion in the as-grown crystals, a special procedure has been developed. Room temperature optical absorption spectra reveal the characteristic UV absorption bands of the Yb 2+ ions in the as-grown crystals, with intensities more than 10 times higher than those reported by other authors using various conversion procedures. The influence of YbF 3 content and of codoping with Pb 2+ ions on the absorption and emission spectra has been studied. Room temperature emission bands in the near UV (not reported before) and in the visible spectral domain have been observed. The emission intensity depends on the dopant concentration. A comparison of our results with those obtained by other authors is also given. r
Applied Physics B, 2013
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Synthesis and down-conversion luminescence investigation of CaF2:Yb:Ce powders for photonics
Journal of Fluorine Chemistry, 2019
Highlights The single-phase solid solutions of calcium fluoride doped with ytterbium and cerium trivalent ions have been synthesized by the precipitation from aqueous solutions technique. Analysis of the luminescence kinetics has shown significant energy transfer from Ce 3+ to Yb 3+ under excitation upon 266 nm. The maximum down-conversion Yb 3+ luminescence quantum yield (5.6%) upon 266 nm pumping was recorded for the CaF2:Ce(0.1 mol%):Yb (10 mol%) solid solution.
Growth of YbF 3-doped CaF 2 crystals and characterization of Yb 3+/Yb 2+ conversion
Journal of Crystal Growth, 2008
Calcium fluoride crystals doped with YbF 3 and PbF 2 -, NaF-and LiF-codoped were grown using the vertical Bridgman method. Transparent, high quality, with various high Yb 2+ contents in the as-grown crystals has been obtained using a special procedure. The optical absorption spectra reveal the characteristic ultraviolet (UV) absorption bands of the divalent Yb ions. Influence of the codoping with Pb 2+ , Li + and Na + ions on the absorption spectra and on the Yb 2+ ions content has been studied. High-intensity emission bands in the near-UV spectral region, not reported before, have been observed for excitation by 230 nm. A comparison of our results with those obtained by other authors is also given. r
Yb:CaF2 — a new old laser crystal
Applied Physics B, 2009
Here is presented and discussed the history, the spectroscopic, the thermo-mechanical and the laser properties of the new old laser crystal Yb:CaF 2 , of its Sr and Ba isotypes as well as of an Yb and Na codoped compound. It will be shown that Yb:CaF 2 is a very particular luminescent material, in which the laser-active center probably consists of a complex hexameric cluster, that it is the most promising Yb-doped fluoride material for large-scale, high-power and high-energy laser systems and that it can compete in several aspects with the currently used Yb-doped oxide crystals and glasses. The opportunity of operating the crystals at cryogenic temperatures and the recently achieved improvements in the field of femtosecond pulsed laser operation and high peak power laser amplification is highlighted and evaluated.
Concentration distribution of Yb2+ and Yb3+ ions in YbF3:CaF2 crystals
Journal of Crystal Growth, 2008
Calcium fluoride crystals doped with YbF 3 were grown using the Bridgman technique. The optical absorption spectra reveal the characteristic UV-absorption bands of divalent Ytterbium. The absorption coefficient of divalent Yb is more than ten times higher than that of trivalent Ytterbium. This shows that the developed crystal growth process achieves a good Yb 3+ -Yb 2+ conversion. The concentration distribution of the Yb 2+ and Yb 3+ ions among two of the samples was investigated using the optical absorption method. Taking into account the relationship between the optical absorption coefficient and the concentration of the impurities in the sample, the segregation coefficient of the two types of ytterbium ions has been calculated. From our calculations, we obtained the results that the segregation coefficient of the Yb 3+ ions in a CaF 2 host is E1, and for Yb 2+ ions is ol. r
Role of monovalent alkali ions in the Yb 3+ centers of CaF 2 laser crystals
Radiation Measurements, 2010
a b s t r a c t Yb 3þ and M þ monovalent alkali ions (M þ ¼ Li þ , Na þ , K þ )-co-doped CaF 2 cubic laser crystals were grown by the micro-pulling-down method (m-PD) under CF 4 atmosphere. Structural and spectroscopic characterizations of Yb 3þ in substitution of Ca 2þ (absorption, emission and decay curves) were carried out to study the effect of M þ ions as charge compensators.