The Experts below are selected from a list of 243 Experts worldwide ranked by ideXlab platform

Richard E Riman - One of the best experts on this subject based on the ideXlab platform.

  • Blue, green and red fluorescence and energy transfer of Eu3+ in Fluoride Glasses
    Journal of Luminescence, 1995
    Co-Authors: M. Dejneka, Elias Snitzer, Richard E Riman
    Abstract:

    Solid state blue and green light sources are desirable for high density optical storage, color displays, optoelectronics, and medical diagnostics. In addition to the well-known red emission of Eu3+, strong green, blue, and ultraviolet emissions have been observed in Eu3+ doped ZBLA (57ZrF4·36BaF2·4LaF3·3AlF3) and PIGLZ (43PbF2·17InF3·17GaF3·4LaF3·19ZnF2) Fluoride Glasses. The intense concentration dependence of these emissions was examined with fluorescence and excitation spectroscopy and found to be caused by nonradiative dipole-quadrupole and dipole-dipole energy transfer between excited and ground state Eu3+ ions. Judd-Ofelt analysis, transfer efficiency, and phonon side band measurements were used to model the fluorescence, energy transfer, and gain cross section for Eu3+ in a ZBLA host. © 1995.

  • reactive atmosphere synthesis of sol gel heavy metal Fluoride Glasses
    Journal of Materials Research, 1992
    Co-Authors: A M Mailhot, Abdessamad Elyamani, Richard E Riman
    Abstract:

    A glass based on ZrF4 was synthesized by a combination of sol-gel and reactive atmosphere processing. Infrared spectroscopy and combustion analysis show that the fluorination process reduces the concentration of organic and hydroxide impurities. Chemical changes have occurred during fluorination; this is indicated by different x-ray diffraction traces and crystallization characteristics for the fluorinated sample compared to the oxide gel product. Chemical analysis from x-ray fluorescence indicates that the fluorinated gel is chemically similar to a melted glass of the same composition. Differential scanning calorimetry gives a glass transition temperature of 290 °C and a crystallization temperature of 390 °C. These values are consistent with those expected for a Fluoride glass prepared by conventional methods.

Junjie Zhang - One of the best experts on this subject based on the ideXlab platform.

  • enhanced 2 7 and 2 9 μm emissions in er3 ho3 doped Fluoride Glasses sensitized by pr3 ions
    Materials Research Bulletin, 2016
    Co-Authors: Ying Tian, Tao Wei, Xufeng Jing, Junjie Zhang
    Abstract:

    Abstract In this report, Er3+/Ho3+/Pr3+ tri-doped Fluoride glass was prepared. The enhancement of 2.7 and 2.9 μm emissions from Er3+/Ho3+doped system were achieved successfully after the addition of Pr3+. The combination of low OH− concentration, low maximum phonon energy and high mid-infrared transmittance is beneficial to the realization of mid-infrared emissions. The energy transfer mechanism among Er3+, Ho3+ and Pr3+ was investigated. The decay profiles of several levels were measured to further examine the enhanced mid-infrared emissions. Moreover, high stimulated emission cross sections at 2.7- and 2.9 μm (1.08 × 10−20 cm2 and 2.0 × 10−20 cm2, respectively) were determined. Er3+/Ho3+/Pr3+ tri-doped Fluoride glass might provide a new choice for mid-infrared laser.

  • highly er 3 doped zrf4 based Fluoride Glasses for 2 7 μm laser materials
    Applied Optics, 2013
    Co-Authors: Feifei Huang, Yanyan Guo, Liyan Zhang, Junjie Zhang
    Abstract:

    A new type of Fluoride Glasses with high erbium-doping concentration (up to 6 mol. % Er(3+)) is investigated. The intensive 2.7 μm fluorescence is demonstrated with minimized concentration quenching. The intensity parameters and radiative properties are determined from the absorption spectrum based on the Judd-Ofelt theory. The prepared Er(3+)-doped ZBYA glass possesses high predicted spontaneous-transition probability (28.92 s(-1)) and large calculated emission cross section (9.8×10(-21) cm(2)). All these results indicate that this Er(3+)-doped ZrF(4)-based Fluoride glass has potential applications in 2.7 μm laser materials.

  • er3 doped fluoro tellurite glass a new choice for 2 7 μm lasers
    Materials Letters, 2012
    Co-Authors: Ming Li, Lili Hu, Junjie Zhang
    Abstract:

    Abstract A novel erbium ion doped fluoro-tellurite Glasses were prepared, and 2.7 μm emission properties, thermal stability and chemical durability were investigated. An intense 2.7 μm emission was observed. It was also found that the thermal stability and chemical durability were greatly improved by introducing a small amount of TeO 2 into Fluoride Glasses. In addition, the spontaneous transition probability (A) and branching ratios (β) of Er 3+ -doped fluoro-tellurite Glasses were calculated and analyzed. The present Er 3+ -doped fluoro-tellurite Glasses with large 2.7 μm emission cross-sections (6.32 × 10 − 21  cm 2 ) indicate that it has a very promising application for solid state lasers around 3 μm.

  • effects of chloride substitution on the chemical and physical properties and the crystallization behavior in heavy metal Fluoride Glasses
    Journal of Alloys and Compounds, 2008
    Co-Authors: Junjie Zhang, Guonian Wang, Zhonghong Jiang
    Abstract:

    Abstract Effect of the substitutions of chloride for Fluoride on the chemical and physical properties and the crystallization behavior in heavy metal Fluoride Glasses has been investigated. The characteristic temperature of the glass does not changed obviously when the Fluoride was taken place by chloride. Compared with samples of being free of ErF 3 , the doping samples are more inclined to be surface crystallization. Optical basicity in the glass system increases with increasing the negative charge provided by the chloride atoms and the absorption peak red shifted is observed in absorption spectra. XRD measurements show that not a single crystalline phase appears in the heated glass samples, which indicate the substitutions of chloride for Fluoride with a variety of crystalline precipitation trends.

B Boulard - One of the best experts on this subject based on the ideXlab platform.

  • visible to near infrared down shifting in tm 3 doped Fluoride Glasses for solar cells efficiency enhancement
    Optical Materials, 2016
    Co-Authors: B Boulard, Olfa Maalej, Julien Merigeon, Mihaela Girtan
    Abstract:

    Abstract In this paper, down-conversion of Tm 3+ doped Fluoride ZLAG Glasses with composition of 70.2ZrF 4 –(23.4−x)LaF 3 –0.6AlF 3 –5.8GaF 3 –xTmF 3 (x = 0.25, 0.5, 0.75, 1, 2, 3 and 5 mol%) were tested as encapsulation materials for solar cells. The current density – voltage (J-V) characterizations were performed under solar simulator irradiation. The influence of Tm 3+ concentration on the mono crystalline silicon solar cells performances was investigated. A slight increase of the solar cell efficiency was observed in the case of Fluoride ZLAG for Tm 3+ doping concentrations up to 1 mol% Tm 3+ . Further increase of the Tm 3+ concentration leads to a decrease of solar cell conversion efficiency as a result of concentration quenching.

  • study with analytical equations of absorption spectra containing interference dips in Fluoride Glasses doped with cr3
    Journal of Physical Chemistry B, 2016
    Co-Authors: O Maalej, O Taktak, B Boulard, Souha Kammoun
    Abstract:

    The optical absorption of Cr3+-doped Fluoride Glasses has been investigated. The lowest energy absorption band 4A2 → 4T2 shows distinct interference dips due to spin–orbit coupling between 4T2, 2E and 2T1 excited states. The dips were analyzed using an analytical method proposed by Bussiere et al. (J. Phys. Chem. A 2003, 107, 1258) based on coupled potential energy surfaces. Then a theoretical crystal-field analysis based on the Racah tensor algebraic method was carried on Cr3+ ions occupying octahedral site symmetry in the Fluoride Glasses. Satisfactory correlations were obtained between the experimental and calculated energy levels. The fitting of the interference dips also provided a measure of the spin–orbit coupling constant for Cr3+ in Fluoride Glasses, intermediate between the theoretical value calculated for a Fluoride crystal and the value deduced from Racah parameters.

  • downconversion in pr3 yb3 co doped zbla Fluoride Glasses
    Journal of Luminescence, 2015
    Co-Authors: O Maalej, B Boulard, Belto Dieudonne, Maurizio Ferrari, M Dammak
    Abstract:

    Abstract Fluorozirconate ZBLA Glasses with molar composition 57ZrF 4 –34BaF 2 –5LaF 3 –4AlF 3 –0.5PrF 3 – x YbF 3 (from x =0 to 10) were synthesized to evaluate the rate of the conversion of visible photons into infrared photons. The emission spectra in the near infrared (NIR) at 950–1100 nm and the luminescence decays in the visible and NIR indicate an energy transfer from Pr 3+ to Yb 3+ upon blue excitation of Pr 3+ at 440 nm. The energy transfer efficiency increases with Yb 3+ concentration to reach 86% with 0.5Pr 3+ –10Yb 3+ co-doping (in mol%). However, the quenching of the Yb 3+ emission strongly reduces the efficiency of the downconversion process: the decay time values decrease from 600 µs ( x =0.5 mol%) to 85 µs ( x =10 mol%).

  • up and down conversion in yb3 pr3 co doped Fluoride Glasses and glass ceramics
    Journal of Non-crystalline Solids, 2013
    Co-Authors: Belto Dieudonne, B Boulard, G Alombertgoget, A Chiasera, Y Gao, Stephanie Kodjikian, Maurizio Ferrari
    Abstract:

    Abstract Pr3 +–Yb3 + co-doped transparent ZrF4-based bulk and planar waveguide glass ceramics (GCs) have been fabricated using the physical vapor deposition. X-ray diffraction and transmission electron microscopy analysis have shown the presence of a single crystalline phase that belongs to the LaF3–ZrF4 system. Upon 980 nm excitation, blue, orange and red emissions have been obtained both in bulk and waveguides. Intense luminescence of Yb3 + ions has been observed after excitation at 476 nm and is ascribed by to energy transfer (ET) from Pr3 + to Yb3 +. The ET efficiency was estimated to be 92% for 0.5 mol% Pr3 +–10 mol% Yb3 + co-doping.

O Maalej - One of the best experts on this subject based on the ideXlab platform.

  • study with analytical equations of absorption spectra containing interference dips in Fluoride Glasses doped with cr3
    Journal of Physical Chemistry B, 2016
    Co-Authors: O Maalej, O Taktak, B Boulard, Souha Kammoun
    Abstract:

    The optical absorption of Cr3+-doped Fluoride Glasses has been investigated. The lowest energy absorption band 4A2 → 4T2 shows distinct interference dips due to spin–orbit coupling between 4T2, 2E and 2T1 excited states. The dips were analyzed using an analytical method proposed by Bussiere et al. (J. Phys. Chem. A 2003, 107, 1258) based on coupled potential energy surfaces. Then a theoretical crystal-field analysis based on the Racah tensor algebraic method was carried on Cr3+ ions occupying octahedral site symmetry in the Fluoride Glasses. Satisfactory correlations were obtained between the experimental and calculated energy levels. The fitting of the interference dips also provided a measure of the spin–orbit coupling constant for Cr3+ in Fluoride Glasses, intermediate between the theoretical value calculated for a Fluoride crystal and the value deduced from Racah parameters.

  • downconversion in pr3 yb3 co doped zbla Fluoride Glasses
    Journal of Luminescence, 2015
    Co-Authors: O Maalej, B Boulard, Belto Dieudonne, Maurizio Ferrari, M Dammak
    Abstract:

    Abstract Fluorozirconate ZBLA Glasses with molar composition 57ZrF 4 –34BaF 2 –5LaF 3 –4AlF 3 –0.5PrF 3 – x YbF 3 (from x =0 to 10) were synthesized to evaluate the rate of the conversion of visible photons into infrared photons. The emission spectra in the near infrared (NIR) at 950–1100 nm and the luminescence decays in the visible and NIR indicate an energy transfer from Pr 3+ to Yb 3+ upon blue excitation of Pr 3+ at 440 nm. The energy transfer efficiency increases with Yb 3+ concentration to reach 86% with 0.5Pr 3+ –10Yb 3+ co-doping (in mol%). However, the quenching of the Yb 3+ emission strongly reduces the efficiency of the downconversion process: the decay time values decrease from 600 µs ( x =0.5 mol%) to 85 µs ( x =10 mol%).

Animesh Jha - One of the best experts on this subject based on the ideXlab platform.

  • spectroscopic properties of sm3 doped oxide and Fluoride Glasses for efficient visible lasers 560 660 nm
    Optics Communications, 2008
    Co-Authors: Lihui Huang, Animesh Jha, Shaoxiong Shen
    Abstract:

    Abstract The spectroscopic properties of Sm 3+ -ions in tellurite, fluorophosphate, and fluorine-modified silicate Glasses are examined under the excitations at 488 nm (Ar + ion laser) and 1060 nm laser. The effect of dopant ion and glass–host interaction, branching ratio of transitions and line shapes of emission lines in the visible region are discussed in view of the ionicity and covalency of hosts. The lifetimes of metastable levels are also reported and the results are explained for designing the visible and UV laser hosts.

  • the influence of f ion doping on the fluorescence 4i13 2 4i15 2 line shape broadening in er3 doped oxyFluoride silicate Glasses
    Optical Materials, 2004
    Co-Authors: Shaoxiong Shen, Animesh Jha
    Abstract:

    Abstract The doping of fluorine in silicate Glasses is of particular interest for enhancing the spectroscopic properties of rare-earth ion doped devices currently used in telecommunication networks. This glass host combines the structural properties of both silicate and Fluoride Glasses by providing a range of structural sites for Er-ions, which are essential for designing planar and fibre amplifiers with high Er-ion solubility. In this investigation a series of fluorine modified silicate Glasses are reported and their measured spectroscopic and physical properties are compared. On the basis of structural models of silicates known in the literature, the effects of the incorporation of F − , Al 3+ ions and network formers such as GeO 2 , P 2 O 5 , and B 2 O 3 on the broadening of emission line shape for the 4 I 13/2  →  4 I 15/2 transition of Er-ion are analysed. Structural aspects of large solubility for Er-ions in the oxyFluoride silicate hosts are also discussed by making comparison with the data available in the literature. We also report an unusual concentration quenching characteristics in oxyFluoride silicate Glasses, which is important for amplifier and laser design and are not known in the literature. Based on the spectroscopic properties of oxyFluoride Glasses, the figures-of-merit (FOM) for amplifier design are compared and the relationships with the F/O ratio in the glass and spectroscopic properties of the device are also discussed.

  • effects of the site symmetry and host polarizability on the hypersensitive transition 3p0 3f2 of pr3 in Fluoride Glasses
    Journal of Applied Physics, 1999
    Co-Authors: V K Tikhomirov, M Naftaly, Animesh Jha
    Abstract:

    Observations and analysis of hypersensitive 3P0→3F2 transition of Pr3+ ion are reported in a series of Fluoride (fluoroindate, fluoroaluminate, and fluorozirconate) Glasses. The data in Fluoride families are also compared with the data on the selected tellurite and sulfide Glasses. The structure of dopant sites in Fluoride Glasses and the mechanism of hypersensitivity are discussed in relation to the symmetry of dopant sites and host polarizability. The possibilities of quenching, or alternatively, of magnification of the hypersensitive transitions of rare-earth ions in the glassy hosts and their applications are discussed.

  • Improved Fluoride Glasses for 1.3 μm optical amplifiers
    Journal of Non-Crystalline Solids, 1993
    Co-Authors: R.s. Deol, Daniel W. Hewak, S. Jordery, Animesh Jha, M. Poulain, Maria Dolores Baró, David N. Payne
    Abstract:

    Abstract Preliminary materials results are reported of a study to develop novel Fluoride Glasses exhibiting maximum phonon energies lower than those of ZBLAN with the objective of realising an efficient optical amplifier for the coveted 1.3 μm wavelength domain. Pertinent material attributes including peak phonon energy, 1 G 4 lifetimes and thermal properties are reported for each glass host.