Science.gov

Sample records for borate glasses doped

  1. Synthesis and structural studies of praseodymium doped silver borate glasses

    SciTech Connect

    Jagadeesha Gowda, G. V.; Eraiah, B.

    2013-02-05

    Praseodymium doped silver borate glasses with nominal composition xPr{sub 6}O{sub 11}-(25-x)Ag{sub 2}O-75B{sub 2}O{sub 3} (x=0, 1, 2, 3, 4, 5) were prepared by melt quench technique. XRD pattern shows that there is no sharp peak it confirms the amorphous nature of the present glasses. The glass transition temperature (T{sub g}) of this glass system have been studied using the Matac MBS-8000 Digital Signal Processing and Conventional Thermal Analysis (DTA) method. The T{sub g} of these glasses increases with increase in concentration of Pr{sub 6}O{sub 11} except at 0.2 mol%, T{sub g} value is lower. {sup 11}B MAS-NMR shows the presence of sharp peak around 0.306 ppm. Chemical shift of these glasses decreases with mol% of rare earth oxide. FTIR spectra recorded in the region of 400 to 4000 cm{sup -1}. This studies revealed that the progressive addition Ag{sub 2}O and Pr{sub 6}O{sub 11} leads to modification of B{sub 2}O{sub 3} into BO{sub 4} groups. Raman measurements of these glasses support the proposed interpretations of the experimental results.

  2. Spectroscopic properties of the Ce-doped borate glasses

    NASA Astrophysics Data System (ADS)

    Kindrat, I. I.; Padlyak, B. V.; Mahlik, S.; Kukliński, B.; Kulyk, Y. O.

    2016-09-01

    The EPR, optical absorption and photoluminescence (emission and excitation) spectra as well as decay kinetics of a series of the Ce-doped glasses with Li2B4O7, LiKB4O7, CaB4O7, and LiCaBO3 compositions have been investigated and analysed. The borate glasses were obtained from the corresponding polycrystalline compounds in the air atmosphere, using standard glass technology. The EPR signals of the isolated Ce3+ and pair Ce3+-Ce3+ centres, coupled by magnetic dipolar and exchange interactions were registered at liquid helium temperatures. The characteristic for glass host broad bands corresponding to the 4f → 5d transitions of the Ce3+centres have been observed in the optical absorption and photoluminescence (emission and excitation) spectra. The obtained luminescence decay curves can be satisfactory described by exponential function with lifetimes in the 19.8-26.1 ns range, which depend on the basic glass composition. The local structure of Ce3+ centres in the investigated glasses has been considered and discussed.

  3. Structural investigation of Zn doped sodium bismuth borate glasses

    NASA Astrophysics Data System (ADS)

    Bhatia, V.; Kumar, D.; Singh, D.; Singh, S. P.

    2016-05-01

    A series of Bismuth Borate Oxide Glass samples with composition x(ZnO):(15-x)Na2O:15Bi2O3:70B2O3 (variation in x is from 6 to 12 mole %) have been prepared by conventional melt quenching technique. All the chemicals used were of Analytical Grade. In order to verify the amorphous nature of the prepared samples the X-Ray Diffraction (XRD) was done. The physical and structural properties have been explored by using the techniques such as density, molar volume and FTIR in order to understand the effect of alkali and transition metal ions on the structure of these glasses. The results obtained by these techniques are in good agreement to one another and with literature as well. With the increase in the content of ZnO, the increase in density and some variations in structural coordination (ratio of BO3 & BO4 structural units) have been observed.

  4. Infrared-to-visible upconversion luminescence in neodymium-doped bismuth-borate glass

    NASA Astrophysics Data System (ADS)

    Oprea, Isabella-Ioana; Hesse, Hartmut; Betzler, Klaus

    2005-10-01

    The upconversion luminescence in Nd3+-doped bismuth-borate glass, excited by 0.8 μm light, was studied in the visible spectral region. Four distinct emission bands were found. From their kinetics, two mechanisms can be shown to be responsible for all four lines: energy-transfer upconversion, slightly dominating, and excited state absorption.

  5. Spectroscopic and ultrasonic investigations on structural characterization of borate glass specimen doped with transition metal ions.

    PubMed

    Sathish, K; Thirumaran, S

    2015-08-01

    The present work describes the glass samples of composition (x% V₂O₅-(80-x)% B₂O₃-20% Na₂CO₃) VBS glass system and (x%MnO₂-(80-x)% B₂O₃-20% Na₂CO₃) in MBS glass system with mol% ranging from x=3, 6, 9, 12, 15 and 18 in steps of 3 mol% are prepared by melt quenching technique. For these prepared glass systems, sound velocity (longitudinal and shear velocities) and density have been measured. The sound velocity (longitudinal and shear) was measured by using pulse-echo technique at 5 MHz. The XRD study was carried to out to ascertain the amorphous nature of the glass specimen. Using these measured values, the elastic moduli, Poisson's ratio, Debye temperature, acoustic impedance and thermal expansion coefficient of the two glass systems were evaluated. The elastic and mechanical properties of the prepared glass systems are analyzed from ultrasonic study and the structural characterization from spectroscopic study. The effects due to the doping of transition metal ions with borate have been discussed. In the V₂O₅ doped glass system,(VBS glass system) the sound velocity, density and elastic moduli, steeply increases after 12 mol% comparatively with MnO₂ doped glass system (VBS glass system). The present study critically observes the doping of V₂O₅ with borate enhances the strengthening of network linkage and hardening of the glassy network structure than MnO₂. The IR spectral analysis reveals depolymerization of the borate network and conversion of BO₃ or BO4 units with the formation of non-bridging oxygen. The FTIR spectral studies confirm the presence of various functional groups of the sample. FTIR spectrum of sample exhibits broad absorption bands indicating the wide distribution of borate structural units. The effect of Na₂CO₃, V₂O₅ and MnO₂ contents on the structures of borate glass is evaluated from the FTIR spectra. The topological aspects of the prepared glass samples are exhaustively reported from SEM micrographs

  6. Spectroscopic and ultrasonic investigations on structural characterization of borate glass specimen doped with transition metal ions

    NASA Astrophysics Data System (ADS)

    Sathish, K.; Thirumaran, S.

    2015-08-01

    The present work describes the glass samples of composition (x% V2O5-(80-x)% B2O3-20% Na2CO3) VBS glass system and (x% MnO2-(80-x)% B2O3-20% Na2CO3) in MBS glass system with mol% ranging from x = 3, 6, 9, 12, 15 and 18 in steps of 3 mol% are prepared by melt quenching technique. For these prepared glass systems, sound velocity (longitudinal and shear velocities) and density have been measured. The sound velocity (longitudinal and shear) was measured by using pulse-echo technique at 5 MHz. The XRD study was carried to out to ascertain the amorphous nature of the glass specimen. Using these measured values, the elastic moduli, Poisson's ratio, Debye temperature, acoustic impedance and thermal expansion coefficient of the two glass systems were evaluated. The elastic and mechanical properties of the prepared glass systems are analyzed from ultrasonic study and the structural characterization from spectroscopic study. The effects due to the doping of transition metal ions with borate have been discussed. In the V2O5 doped glass system, (VBS glass system) the sound velocity, density and elastic moduli, steeply increases after 12 mol% comparatively with MnO2 doped glass system (VBS glass system). The present study critically observes the doping of V2O5 with borate enhances the strengthening of network linkage and hardening of the glassy network structure than MnO2. The IR spectral analysis reveals depolymerization of the borate network and conversion of BO3 or BO4 units with the formation of non-bridging oxygen. The FTIR spectral studies confirm the presence of various functional groups of the sample. FTIR spectrum of sample exhibits broad absorption bands indicating the wide distribution of borate structural units. The effect of Na2CO3, V2O5 and MnO2 contents on the structures of borate glass is evaluated from the FTIR spectra. The topological aspects of the prepared glass samples are exhaustively reported from SEM micrographs.

  7. Spectroscopic and ultrasonic investigations on structural characterization of borate glass specimen doped with transition metal ions.

    PubMed

    Sathish, K; Thirumaran, S

    2015-08-01

    The present work describes the glass samples of composition (x% V₂O₅-(80-x)% B₂O₃-20% Na₂CO₃) VBS glass system and (x%MnO₂-(80-x)% B₂O₃-20% Na₂CO₃) in MBS glass system with mol% ranging from x=3, 6, 9, 12, 15 and 18 in steps of 3 mol% are prepared by melt quenching technique. For these prepared glass systems, sound velocity (longitudinal and shear velocities) and density have been measured. The sound velocity (longitudinal and shear) was measured by using pulse-echo technique at 5 MHz. The XRD study was carried to out to ascertain the amorphous nature of the glass specimen. Using these measured values, the elastic moduli, Poisson's ratio, Debye temperature, acoustic impedance and thermal expansion coefficient of the two glass systems were evaluated. The elastic and mechanical properties of the prepared glass systems are analyzed from ultrasonic study and the structural characterization from spectroscopic study. The effects due to the doping of transition metal ions with borate have been discussed. In the V₂O₅ doped glass system,(VBS glass system) the sound velocity, density and elastic moduli, steeply increases after 12 mol% comparatively with MnO₂ doped glass system (VBS glass system). The present study critically observes the doping of V₂O₅ with borate enhances the strengthening of network linkage and hardening of the glassy network structure than MnO₂. The IR spectral analysis reveals depolymerization of the borate network and conversion of BO₃ or BO4 units with the formation of non-bridging oxygen. The FTIR spectral studies confirm the presence of various functional groups of the sample. FTIR spectrum of sample exhibits broad absorption bands indicating the wide distribution of borate structural units. The effect of Na₂CO₃, V₂O₅ and MnO₂ contents on the structures of borate glass is evaluated from the FTIR spectra. The topological aspects of the prepared glass samples are exhaustively reported from SEM micrographs.

  8. Spectroscopic study of neodymium doped lead-bismuth-borate glasses

    NASA Astrophysics Data System (ADS)

    Pasha, Altaf; Dayani, P.; Negalur, Mahesh; Swamy, Manjunatha; Abhiram, J.; Rajaramakrishna, R.

    2016-05-01

    This paper reports on different physical and optical properties of rare earth doped heavy metal oxide glasses. The glass composition of 10Bi2O3-30PbO-60B2O3-xNd2O3 where x = 0, 0.1, 0.2, 0.5 and 1 (in mol %) has been synthesized using melt-quenching technique. Refractive index measurements for these glasses were done and physical parameters were studied. Structural properties of these glasses were analysed through infrared spectra that was recorded between 1600cm-1 and 300cm-1 in transmission mode. The optical absorption spectra were recorded in the wavelength range from 300 to 700 nm. The transitions originated from ground state energy 4I9/2. The energy level analysis has been carried out by considering absorption spectral bands. The results thus obtained are comparable with reports on similar glasses, indicating that the prepared glasses may have potential laser applications.

  9. Study of Relaxation Dynamics in Mixed Iodide Doped Silver-Vanado-Borate Superionic Glass System

    NASA Astrophysics Data System (ADS)

    Sharma, Poonam; Kanchan, D. K.; Pant, Meenakshi; Gondaliya, Nirali; Jayswal, Manish S.

    2011-07-01

    Electrical conductivity and impedance measurements were carried out for a new mixed metal iodide salt doped silver vanado-borate i.e., [(PbI2-CuI)-Ag2O-V2O5-B2O3] super-ionic glass system. The impedance plots (Z″ vs. Z') for all the prepared glass samples were recorded and found to exhibit depressed semi circles over the studied temperature range. Frequency dependence of the imaginary part of impedance Z″ and the imaginary part of modulus M″ at different temperatures were also investigated. Also, relaxation dynamics in framework of modulus formalism has been discussed.

  10. Rare earth-doped lead borate glasses and transparent glass-ceramics: structure-property relationship.

    PubMed

    Pisarski, W A; Pisarska, J; Mączka, M; Lisiecki, R; Grobelny, Ł; Goryczka, T; Dominiak-Dzik, G; Ryba-Romanowski, W

    2011-08-15

    Correlation between structure and optical properties of rare earth ions in lead borate glasses and glass-ceramics was evidenced by X-ray-diffraction, Raman, FT-IR and luminescence spectroscopy. The rare earths were limited to Eu(3+) and Er(3+) ions. The observed BO(3)↔BO(4) conversion strongly depends on the relative PbO/B(2)O(3) ratios in glass composition, giving important contribution to the luminescence intensities associated to (5)D(0)-(7)F(2) and (5)D(0)-(7)F(1) transitions of Eu(3+). The near-infrared luminescence and up-conversion spectra for Er(3+) ions in lead borate glasses before and after heat treatment were measured. The more intense and narrowing luminescence lines suggest partial incorporation of Er(3+) ions into the orthorhombic PbF(2) crystalline phase, which was identified using X-ray diffraction analysis. PMID:21093353

  11. Elastic properties of silver borate glasses doped with praseodymium oxide

    SciTech Connect

    Gowda, G. V. Jagadeesha; Eraiah, B.

    2014-04-24

    A series of glasses xPr{sub 6}O{sub 11−}(35−x) Ag{sub 2}O−65B{sub 2}O{sub 3} with x=0, 0.1, 0.2, 0.3, 0.4 and 0.5 mol % were synthesized by melt quenching technique. Longitudinal and shear ultrasonic velocity were measured at 5 MHz frequency and at room temperature. Elastic moduli, Poisson's ratio and Debye temperature have been calculated from the measured density and ultrasonic velocity at room temperature. The experimental results indicate that the elastic constants depend upon the composition of the glasses. The role of the Pr{sub 6}O{sub 11} inside the glass network was discussed.

  12. Optical Properties of Alkaline Earth Ions Doped Bismuth Borate Glasses

    SciTech Connect

    Kundu, Virender; Dhiman, R. L.; Maan, A. S.; Goyal, D. R.

    2011-07-15

    The optical properties of glasses with composition xLi{sub 2}O(30-x)Bi{sub 2}O{sub 3}-70B{sub 2}O{sub 3}; x = 0, 5, 10, 15 and 20 mol %, prepared by normal melt quench technique were investigated by means of UV-VIS measurement. It was observed that the optical band gap of the present glass system decreases with increasing Li{sub 2}O content up to 15 mol%, and with further increase in lithium oxide content i.e. x>15 mol% the optical band gap increases. It was also observed that the present glass system behaves as an indirect band gap semiconductor.

  13. Luminescence of erbium-doped bismuth borate glasses

    NASA Astrophysics Data System (ADS)

    Oprea, Isabella-Ioana; Hesse, Hartmut; Betzler, Klaus

    2006-07-01

    Absorption and luminescence properties of erbium ions in the binary glass system bismuth oxide (Bi 2O 3)-boric oxide (B 2O 3) are measured for the composition range 25-65 mol% Bi 2O 3. A Judd-Ofelt analysis of the typical erbium bands in the absorption spectra reveals comparably high Judd-Ofelt coefficients. This indicates a substantial mixing of other electronic configuration into the 4f N configuration by the random crystal fields in the glasses. All coefficients are decreasing with increasing Bi 2O 3 content, this effect being most pronounced with Ω2. Luminescence decay times and radiative efficiencies show an expressed dependence on the glass composition. Radiative efficiencies of all luminescence bands increase with increasing Bi 2O 3 content—accompanied, however, by a slight narrowing of the bands. Except the common luminescence bands of erbium, upconversion luminescence at a wavelength of 0.54 μm could be detected.

  14. Optical properties of Nd3+ doped bismuth zinc borate glasses

    NASA Astrophysics Data System (ADS)

    Shanmugavelu, B.; Venkatramu, V.; Ravi Kanth Kumar, V. V.

    2014-03-01

    Glasses with compositions of (100-x) (Bi2ZnOB2O6) - x Nd2O3 (where x = 0.1, 0.3, 0.5, 1 and 2 mol%) were prepared by melt quenching method and characterized through optical absorption, emission and decay curve measurements. Optical absorption spectra have been analyzed using Judd-Ofelt theory. The emission spectra exhibit three peaks at 919, 1063 and 1337 nm corresponding to 4F3/2 to 4I9/2, 4I11/2 and 4I13/2 transitions in the near infrared region. The emission intensity of the 4F3/2 to 4I11/2 transition increases with increase of Nd3+ concentration up to 1 mol% and then concentration quenching is observed for 2 mol% of Nd3+ concentration. The lifetimes for the 4F3/2 level are found to decrease with increase in Nd2O3 concentration in the glasses. The decay curves of the glass up to 0.3 mol% of Nd3+ exhibit single exponential nature and thereafter the curves become nonexponential nature (0.5, 1 and 2 mol%). The nonexponential curve has been fitted to the Inokuti-Hirayama model to understand the nature of energy transfer process.

  15. Optical studies of Sm3+ ions doped Zinc Alumino Bismuth Borate glasses

    NASA Astrophysics Data System (ADS)

    Swapna, K.; Mahamuda, Sk.; Srinivasa Rao, A.; Shakya, S.; Sasikala, T.; Haranath, D.; Vijaya Prakash, G.

    Zinc Alumino Bismuth Borate (ZnAlBiB) glasses doped with different concentrations of samarium (Sm3+) ions were prepared by using melt quenching technique and characterized for their lasing potentialities in visible region by using the techniques such as optical absorption, emission and emission decay measurements. Radiative properties for various fluorescent levels of Sm3+ ions were estimated from absorption spectral information using Judd-Ofelt (JO) analysis. The emission spectra and con-focal photoluminescence images obtained by 410 nm laser excitation demonstrates very distinct and intense orange-red emission for all the doped glasses. The suitable concentration of Sm3+ ions in these glasses to act as an efficient lasing material has been discussed by measuring the emission cross-section and branching ratios for the emission transitions. The quantum efficiencies were also been estimated from emission decay measurements recorded for the 4G5/2 level of Sm3+ ions. From the measured emission cross-sections, branching ratios, strong photoluminescence features and CIE chromaticity coordinates, it was found that 1 mol% of Sm3+ ions doped ZnAlBiB glasses are most suitable for the development of visible orange-red lasers.

  16. Spectroscopic properties and luminescence behavior of Nd3+ doped zinc alumino bismuth borate glasses

    NASA Astrophysics Data System (ADS)

    Mahamuda, Sk.; Swapna, K.; Srinivasa Rao, A.; Jayasimhadri, M.; Sasikala, T.; Pavani, K.; Rama Moorthy, L.

    2013-09-01

    Zinc Alumino Bismuth Borate (ZnAlBiB) glasses doped with different concentrations of neodymium are prepared by using the melt quenching technique to study their physical, absorption and luminescence properties to understand the lasing potentialities of these glasses. From the absorption spectra various spectroscopic parameters and Judd-Ofelt (JO) parameters are evaluated. These JO parameters are used to calculate the transition probability (A), radiative lifetime (τR), and branching ratios (βR) for most of the fluorescent levels of Nd3+. The emission spectra recorded for these glasses gives three prominent transitions 4F3/2→4I9/2, 4F3/2→4I11/2 and 4F3/2→4I13/2 for which effective band widths (ΔλP) and stimulated emission cross-sections (σse) are evaluated. Branching ratios and stimulated emission cross-sections measured for all these glasses show that the 4F3/2→4I11/2 transition under investigation has the potential for laser applications. The intensity of Nd3+ emission spectra increases with increasing concentrations of Nd3+ up to 1 mol% and beyond 1 mol% the concentration quenching is observed. The high stimulated emission cross-section and branching ratios from the present glasses suggests their potential for infrared lasers. From the absorption and emission spectral studies it was found that, 1 mol% of Nd3+ ion concentration is optimum for Zinc Alumino Bismuth Borate glasses to generate a strong laser emission at 1060 nm.

  17. Spectroscopic Study on Eu3+ Doped Borate Glasses Containing Ag Nanoparticles and Ag Aggregates.

    PubMed

    Fu, Shaobo; Zheng, Hui; Zhang, Jinsu; Li, Xiangping; Sun, Jiashi; Hua, Ruinian; Dong, Bin; Xia, Haiping; Chen, Baojiu

    2015-01-01

    Transparent Eu(3+)-doped borate glasses containing Ag nanoparticles and Ag aggregates with composition (40 - x) CaO-59.5B2O3-0.5Eu2O3-xAgNO3 were prepared by a simple one-step melt-quenching technique. The X-ray diffraction (XRD) patterns of the glasses reveal amorphous structural properties and no diffraction peaks belonging to metal Ag particles. Ag particles and Ag aggregates were observed from the absorption spectra. Effective energy transfers from the Ag aggregates to the Eu3+ ions were observed in the excitation spectra from monitoring the intrinsic emission of Eu3+x .5D0 --> 7F2. The glasses with higher Ag content can be effectively excited by light in a wide wavelength region, indicating that these glasses have potential application in the solid state lighting driven by semiconductor light emitting diodes (LEDs). The emission spectra of the samples with higher Ag contents exhibit plenteous spectral components covering the full visible region from violet to red, thus indicating that these glass materials possess an excellent and tunable color rendering index. The color coordinates for all the glass samples were calculated by using the intensity-corrected emission spectra and the standard data issued by the CIE (Commission International de l' Eclairage) in 1931. It was found that the color coordinates for most samples with higher Ag contents fall into the white region in the color space. PMID:26328363

  18. Thermoluminescence Response of Copper-Doped Potassium Borate Glass Subjected to 6 Megavolt X-Ray Irradiation

    NASA Astrophysics Data System (ADS)

    Hossain, I.; Shekaili, N. K.; Wagiran, H.

    2015-03-01

    This study addresses the characteristics of Cu-doped and undoped potassium borate glass for use as ionizing radiation dosimeters by investigating and comparing the thermoluminescence responses, linearity, sensitivity and dose response s of the two types of glasses. A number of samples based on xK 2 CO 3 + (100 - x)H 3 BO 3 , where 10 ≤ x ≤ 30 mol.%, have been prepared using a melt quenching technique. The amorphous phases were identified using X-ray diffraction (XRD). The undoped potassium borate samples 20K 2 CO 3 + 80H 3 BO 3 (mol.%) and Cu-doped (0.5 mol.%) samples were placed in a solid phantom apparatus and irradiated with in X-ray tube under 6 MV accelerating voltage with doses ranging from 0.5 to 4.0 Gy. This beam was produced by the Primus MLC 3339 linear accelerator (LINAC) available at Hospital Sultan Ismail, Johor Bahru, Malaysia. The results clearly show the superiority of Cu-doped glass in terms of response and sensitivity to producing luminescence over undoped potassium borate glass. The sensitivity of Cu-doped glass is 6.75 times greater than that of undoped glass.

  19. Optical absorption and heating rate dependent glass transition in vanadyl doped calcium oxy-chloride borate glasses

    NASA Astrophysics Data System (ADS)

    Dahiya, M. S.; Khasa, S.; Agarwal, A.

    2015-04-01

    Some important results pertaining to optical and thermal properties of vanadyl doped oxy-halide glasses in the chemical composition CaCl2-CaO-B2O3 are discussed. These glasses have been prepared by conventional melt quench technique. From X-ray diffraction (XRD) profiles the amorphous nature of the doped glasses has been confirmed. The electronic polarizability is calculated and found to increase with increase in chloride content. The optical absorption spectra have been recorded in the frequency range of 200-3200 nm. Recorded spectra are analyzed to evaluate cut-off wavelength (λcut-off), optical band gap (Eg), band tailing (B), Urbach energy (ΔE) and refractive index (n). Thermal analysis has been carried out for the prepared glasses at three different heating rates viz. 5, 10 and 20 °C/min. The glass transition temperature (Tg) along with thermal activation energy (Ea) corresponding to each heating rate are evaluated from differential scanning calorimetry (DSC) thermographs. It is found that Ea decrease and Tg increase with increase in heating rate. The variation in Tg is also observed with the substitution of calcium chloride in place of calcium oxide. The increasing and higher values of Ea suggest that prepared glasses have good thermal stability. Variation in Tg and Eg suggests that Cl- anions enter into the voids of borate network at low concentrations (<5.0%) and contribute to the network formation at high concentration (>5.0%).

  20. Thermoluminescence properties of the Cu-doped lithium potassium borate glass.

    PubMed

    Aboud, Haydar; Wagiran, H; Hussin, R; Ali, Hassan; Alajerami, Yasser; Saeed, M A

    2014-08-01

    Characteristics of lithium potassium borate glasses with various copper concentrations are reported. The glasses were prepared by the melt quenching method and irradiated with photons to doses in the 0.5-4.0 Gy range. Glowing curves, dose response curves, reproducibility of the response, dose threshold, thermal fading and optical bleaching were studied.

  1. Effect of 3d-transition metal doping on the shielding behavior of barium borate glasses: a spectroscopic study.

    PubMed

    ElBatal, H A; Abdelghany, A M; Ghoneim, N A; ElBatal, F H

    2014-12-10

    UV-visible and FT infrared spectra were measured for prepared samples before and after gamma irradiation. Base undoped barium borate glass of the basic composition (BaO 40%-B2O3 60mol.%) reveals strong charge transfer UV absorption bands which are related to unavoidable trace iron impurities (Fe(3+)) within the chemical raw materials. 3d transition metal (TM)-doped glasses exhibit extra characteristic absorption bands due to each TM in its specific valence or coordinate state. The optical spectra show that TM ions favor generally the presence in the high valence or tetrahedral coordination state in barium borate host glass. Infrared absorption bands of all prepared glasses reveal the appearance of both triangular BO3 units and tetrahedral BO4 units within their characteristic vibrational modes and the TM-ions cause minor effects because of the low doping level introduced (0.2%). Gamma irradiation of the undoped barium borate glass increases the intensity of the UV absorption together with the generation of an induced broad visible band at about 580nm. These changes are correlated with suggested photochemical reactions of trace iron impurities together with the generation of positive hole center (BHC or OHC) within the visible region through generated electrons and positive holes during the irradiation process.

  2. Waveguides and nonlinear index of refraction of borate glass doped with transition metals

    NASA Astrophysics Data System (ADS)

    Almeida, Juliana M. P.; Fonseca, Ruben D.; De Boni, Leonardo; Diniz, Andre Rosa S.; Hernandes, Antonio C.; Ferreira, Paulo H. D.; Mendonca, Cleber R.

    2015-04-01

    The ability to write 3D waveguides by femtosecond laser micromachining and the nonlinear refractive index (n2) spectrum of a new borate glass matrix, containing zinc and lead oxides - (BZP) have been investigated. The transparent matrix was doped with transition metals (CdCl2, Fe2O3, MnO2 and CoO) in order to introduce electronic transitions in visible spectrum, aiming to evaluate their influence on the waveguides and n2 spectrum. We observed that n2 is approximately constant from 600 to 1500 nm, exhibiting an average value of 4.5 × 10-20 m2/W, which is about twice larger than the one for fused silica. The waveguide profile is influenced by the self-focusing effect of the matrix owing to its positive nonlinear index of refraction in the wavelength used for micromachining. A decrease in the waveguide loss of approximately four times was observed for the sample doped with Fe in comparison to the other ones, which may be associated with the change in the optical gap energy.

  3. Optical properties of Lead bismuth borate glasses doped with neodymium oxide.

    PubMed

    Farouk, M; Abd El-Maboud, A; Ibrahim, M; Ratep, A; Kashif, I

    2015-10-01

    Neodymium doped Lead bismuth borate glasses with the composition of 25PbO-25Bi2O3-50B2O3:xNd2O3, where x=0.5, 1, 1.5 and 2 mol%, have been prepared by melt quenching technique. The behavior of the density and molar volume allows concluding that, addition of Nd2O3 leads to the formation of non-bridging oxygen. Rare earth ion parameters have been calculated and studied. The optical band gap (Eg), and band tails (Ee) were determined. Judd-Ofelt theory for the intensity analysis of induced electric dipole transitions has been applied to the measured oscillator strengths of the absorption bands to determine the three phenomenological intensity parameters Ω2, Ω4 and Ω6 for glass. It was observed that the deviation parameters, rms, was found to be 0.56:0.58(×10(-6)). The estimated Judd-Ofelt parameters were found to be Nd2O3concentration dependent. The hypersensitive transition, (4)I9/2→(4)G5/2+(2)G7/2, is closely related to Ω2 parameter.

  4. Spectroscopic investigations on Pr³+ and Nd³+ doped strontium-lithium-bismuth borate glasses.

    PubMed

    Rajesh, D; Balakrishna, A; Seshadri, M; Ratnakaram, Y C

    2012-11-01

    Spectroscopic investigations on different concentrations (0.1, 0.5, 1.0, 1.5 and 2.0mol%) of Pr(3+) and Nd(3+) doped strontium lithium bismuth borate glasses have been done. X-ray diffraction, SEM with EDS, absorption and luminescence spectra were recorded for all the glass matrices and analyzed. X-ray diffraction profiles and SEM images conformed amorphous nature of investigated glass samples. EDS spectra of host glass and Pr(3+)doped glass matrices gave information about the chemical composition of glass samples. From the absorption spectra of Pr(3+) and Nd(3+) ions, Judd-Ofelt (J-O) intensity parameters (Ω(λ),λ=2, 4 and 6) have been calculated and compared with other glass matrices. The emission characteristics such as radiative lifetimes (τ(R)), measured and calculated branching ratios (β) and stimulated emission cross-sections (σ(P)) have been obtained for the observed emission transitions of Pr(3+) and Nd(3+) ions in the above glass matrix for all the concentrations. From the emission spectra of Pr(3+) and Nd(3+) doped glass matrices, the effect of concentration on the quenching of intensity of (1)D(2)→(3)H(4) transition of Pr(3+) ion and (4)F(3/2)→(4)I(9/2), (4)I(11/2) and (4)I(13/2) transitions of Nd(3+) have been studied and discussed.

  5. Broad-spectrum antibacterial properties of metal-ion doped borate bioactive glasses for clinical applications

    NASA Astrophysics Data System (ADS)

    Ottomeyer, Megan

    Bioactive glasses with antimicrobial properties can be implemented as coatings on medical devices and implants, as well as a treatment for tissue repair and prevention of common hospital-acquired infections such as MRSA. A borate-containing glass, B3, is also undergoing clinical trials to assess wound-healing properties. The sensitivities of various bacteria to B3, B3-Ag, B3-Ga, and B3-I bioactive glasses were tested. In addition, the mechanism of action for the glasses was studied by spectroscopic enzyme kinetics experiments, Live-Dead staining fluorescence microscopy, and luminescence assays using two gene fusion strains of Escherichia coli. It was found that gram-positive bacteria were more sensitive to all four glasses than gram negative bacteria, and that a single mechanism of action for the glasses is unlikely, as the rates of catalysis for metabolic enzymes as well as membrane permeability were altered after glass exposure.

  6. One-photon band gap engineering of borate glass doped with ZnO for photonics applications

    SciTech Connect

    Abdel-Baki, Manal; Abdel-Wahab, Fathy A.; El-Diasty, Fouad

    2012-04-01

    Lithium tungsten borate glass of the composition (0.56-x)B{sub 2}O{sub 3}-0.4Li{sub 2}O-xZnO-0.04WO{sub 3} (0 {<=}x{<=} 0.1 mol. %) is prepared for photonics applications. The glass is doped with ZnO to tune the glass absorption characteristics in a wide spectrum range (200-2500 nm). Chemical bond approach, including chemical structure, electronegativity, bond ionicity, nearest-neighbor coordination, and other chemical bonding aspect, is used to analyze and to explain the obtained glass properties such as: transmittance, absorption, electronic structure parameters (bandgap, Fermi level, and Urbach exciton-phonon coupling), Wannier free excitons excitation (applying Elliott's model), and two-photon absorption coefficient as a result of replacement of B{sub 2}O{sub 3} by ZnO.

  7. Thermoluminescence dosimetry properties and kinetic parameters of lithium potassium borate glass co-doped with titanium and magnesium oxides.

    PubMed

    Hashim, S; Alajerami, Y S M; Ramli, A T; Ghoshal, S K; Saleh, M A; Abdul Kadir, A B; Saripan, M I; Alzimami, K; Bradley, D A; Mhareb, M H A

    2014-09-01

    Lithium potassium borate (LKB) glasses co-doped with TiO2 and MgO were prepared using the melt quenching technique. The glasses were cut into transparent chips and exposed to gamma rays of (60)Co to study their thermoluminescence (TL) properties. The TL glow curve of the Ti-doped material featured a single prominent peak at 230 °C. Additional incorporation of MgO as a co-activator enhanced the TL intensity threefold. LKB:Ti,Mg is a low-Z material (Z(eff)=8.89) with slow signal fading. Its radiation sensitivity is 12 times lower that the sensitivity of TLD-100. The dose response is linear at doses up to 10(3) Gy. The trap parameters, such as the kinetics order, activation energy, and frequency factor, which are related to the glow peak, were determined using TolAnal software.

  8. Contribution of Eu ions on the precipitation of silver nanoparticles in Ag-Eu co-doped borate glasses

    SciTech Connect

    Jiao, Qing; Qiu, Jianbei; Zhou, Dacheng; Xu, Xuhui

    2014-03-01

    Graphical abstract: - Highlights: • Silver nanoparticles are precipitated from the borate glasses during the melting process without any further heat treatment. • The reduction of Eu{sup 3+} ions to Eu{sup 2+} ions is presented in this material. • The intensity of Ag{sup +} luminescence. • The introduction of Eu ions accelerated the reaction between Eu{sup 2+} ions and silver ions inducing the silver clusters formation. - Abstract: Ag{sup +} doped sodium borate glasses with different Eu ions concentration were prepared by the melt-quenching method. The absorption at about 410 nm which was caused by the surface plasmon resonance (SPR) of Ag nanoparticles (NPs) is promoted with increasing of Eu ions concentration. Meanwhile, the luminescent spectra showed that the emission intensity of Ag{sup +} decreased while that of the Ag aggregates increased simultaneously. The results indicated that the Ag ions intend to form the high-polymeric state such as Ag aggregates and nanoparticles with increasing of europium ions. Owing to the self-reduction of Eu{sup 3+} to Eu{sup 2+} in our glass system, it revealed that Ag{sup +} has been reduced by the neighboring Eu{sup 2+} which leads to the formation of Ag aggregates and the precipitation of Ag NPs in the matrix. In addition, energy transfer (ET) process from Ag{sup +}/Ag aggregates to the Eu{sup 3+} was investigated for the enhancement of Eu{sup 3+} luminescence.

  9. Identification of ε-Fe2O3 nano-phase in borate glasses doped with Fe and Gd

    NASA Astrophysics Data System (ADS)

    Ivanova, O. S.; Ivantsov, R. D.; Edelman, I. S.; Petrakovskaja, E. A.; Velikanov, D. A.; Zubavichus, Y. V.; Zaikovskii, V. I.; Stepanov, S. A.

    2016-03-01

    A new type of magnetic nanoparticles was revealed in borate glasses co-doped with low contents of iron and gadolinium. Structure and magnetic properties of the particles differ essentially from that of the α-Fe2O3, γ-Fe2O3, or Fe3O4 nanoparticles which were detected earlier in similar glass matrices. Transmission electron microscopy including STEM-HAADF and EDX, synchrotron radiation-based XRD, static magnetic measurements, magnetic circular dichroism, and electron magnetic resonance studies allow referring the nanoparticles to the iron oxide phase-ε-Fe2O3. Analysis of the data set has shown that it is Gd atoms that govern the process of nanoparticles' nucleation and its incorporation into the particles in different proportions can be used to adjust their magnetic and magneto-optical characteristics.

  10. Physical and optical absorption studies of Fe3+ - ions doped lithium borate glasses containing certain alkaline earths

    NASA Astrophysics Data System (ADS)

    Bhogi, Ashok; Kumar, R. Vijaya; Kistaiah, P.

    2016-05-01

    Iron ion doped lithium borate glasses with the composition 15RO-25Li2O-59B2O3-1Fe2O3 (where R= Ca, Sr and Ba) have been prepared by the conventional melt quenching technique and characterized to investigate the physical and optical properties using XRD, density, molar volume and UV-Visible spectroscopy. The optical absorption spectra exhibit a band at around 460 nm which is assigned to 6A1g(S) → 4Eg (G) of Fe3+ ions with distorted octahedral symmetry. From ultraviolet absorption edges, the optical band gap and Urbach energies have been evaluated. The effect of alkaline earths on these properties is discussed.

  11. Thermo-optical characteristics and concentration quenching effects in Nd3+ doped yttrium calcium borate glasses.

    PubMed

    Santos, D R S; Santos, C N; de Camargo, A S S; Silva, W F; Santos, W Q; Vermelho, M V D; Astrath, N G C; Malacarne, L C; Li, M S; Hernandes, A C; Ibanez, A; Jacinto, C

    2011-03-28

    In this work we present a comprehensive study of the spectroscopic and thermo-optical properties of a set of samples with composition xNd(2)O(3)-(5-x)Y(2)O(3-)40CaO-55B(2)O(3) (0 ≤ x ≤ 1.0 mol%). Their fluorescence quantum efficiency (η) values were determined using the thermal lens technique and the dependence on the ionic concentration was analyzed in terms of energy transfer processes, based on the Förster-Dexter model of multipolar ion-ion interactions. A maximum η = 0.54 was found to be substantially higher than for yttrium aluminoborate crystals and glasses with comparable Nd(3+) content. As for the thermo-optical properties of yttrium calcium borate, they are comparable to other well-known laser glasses. The obtained energy transfer microparameters and the weak dependence of η on the Nd(3+) concentration with a high optimum Nd(3+) concentration put this system as a strong candidate for photonics applications. PMID:21456672

  12. Thermoluminescence properties of lithium magnesium borate glasses system doped with dysprosium oxide.

    PubMed

    Mhareb, M H A; Hashim, S; Ghoshal, S K; Alajerami, Y S M; Saleh, M A; Razak, N A B; Azizan, S A B

    2015-12-01

    We report the impact of dysprosium (Dy(3+)) dopant and magnesium oxide (MgO) modifier on the thermoluminescent properties of lithium borate (LB) glass via two procedures. The thermoluminescence (TL) glow curves reveal a single prominent peak at 190 °C for 0.5 mol% of Dy(3+). An increase in MgO contents by 10 mol% enhances the TL intensity by a factor of 1.5 times without causing any shift in the maximum temperature. This enhancement is attributed to the occurrence of extra electron traps created via magnesium and the energy transfer to trivalent Dy(3+) ions. Good linearity in the range of 0.01-4 Gy with a linear correlation coefficient of 0.998, fading as low as 21% over a period of 3 months, excellent reproducibility without oven annealing and tissue equivalent effective atomic numbers ~8.71 are achieved. The trap parameters, including geometric factor (μg), activation energy (E) and frequency factor (s) associated with LMB:Dy are also determined. These favorable TL characteristics of prepared glasses may contribute towards the development of Li2O-MgO-B2O3 radiation dosimeters.

  13. Thermo-optical characteristics and concentration quenching effects in Nd3+ doped yttrium calcium borate glasses.

    PubMed

    Santos, D R S; Santos, C N; de Camargo, A S S; Silva, W F; Santos, W Q; Vermelho, M V D; Astrath, N G C; Malacarne, L C; Li, M S; Hernandes, A C; Ibanez, A; Jacinto, C

    2011-03-28

    In this work we present a comprehensive study of the spectroscopic and thermo-optical properties of a set of samples with composition xNd(2)O(3)-(5-x)Y(2)O(3-)40CaO-55B(2)O(3) (0 ≤ x ≤ 1.0 mol%). Their fluorescence quantum efficiency (η) values were determined using the thermal lens technique and the dependence on the ionic concentration was analyzed in terms of energy transfer processes, based on the Förster-Dexter model of multipolar ion-ion interactions. A maximum η = 0.54 was found to be substantially higher than for yttrium aluminoborate crystals and glasses with comparable Nd(3+) content. As for the thermo-optical properties of yttrium calcium borate, they are comparable to other well-known laser glasses. The obtained energy transfer microparameters and the weak dependence of η on the Nd(3+) concentration with a high optimum Nd(3+) concentration put this system as a strong candidate for photonics applications.

  14. Thermoluminescence properties of lithium magnesium borate glasses system doped with dysprosium oxide.

    PubMed

    Mhareb, M H A; Hashim, S; Ghoshal, S K; Alajerami, Y S M; Saleh, M A; Razak, N A B; Azizan, S A B

    2015-12-01

    We report the impact of dysprosium (Dy(3+)) dopant and magnesium oxide (MgO) modifier on the thermoluminescent properties of lithium borate (LB) glass via two procedures. The thermoluminescence (TL) glow curves reveal a single prominent peak at 190 °C for 0.5 mol% of Dy(3+). An increase in MgO contents by 10 mol% enhances the TL intensity by a factor of 1.5 times without causing any shift in the maximum temperature. This enhancement is attributed to the occurrence of extra electron traps created via magnesium and the energy transfer to trivalent Dy(3+) ions. Good linearity in the range of 0.01-4 Gy with a linear correlation coefficient of 0.998, fading as low as 21% over a period of 3 months, excellent reproducibility without oven annealing and tissue equivalent effective atomic numbers ~8.71 are achieved. The trap parameters, including geometric factor (μg), activation energy (E) and frequency factor (s) associated with LMB:Dy are also determined. These favorable TL characteristics of prepared glasses may contribute towards the development of Li2O-MgO-B2O3 radiation dosimeters. PMID:25828828

  15. Thermo-optical characteristics and concentration quenching effects in Nd3+doped yttrium calcium borate glasses

    NASA Astrophysics Data System (ADS)

    Santos, D. R. S.; Santos, C. N.; de Camargo, A. S. S.; Silva, W. F.; Santos, W. Q.; Vermelho, M. V. D.; Astrath, N. G. C.; Malacarne, L. C.; Li, M. S.; Hernandes, A. C.; Ibanez, A.; Jacinto, C.

    2011-03-01

    In this work we present a comprehensive study of the spectroscopic and thermo-optical properties of a set of samples with composition xNd2O3-(5-x)Y2O3-40CaO-55B2O3 (0 ≤ x ≤ 1.0 mol%). Their fluorescence quantum efficiency (η) values were determined using the thermal lens technique and the dependence on the ionic concentration was analyzed in terms of energy transfer processes, based on the Förster-Dexter model of multipolar ion-ion interactions. A maximum η = 0.54 was found to be substantially higher than for yttrium aluminoborate crystals and glasses with comparable Nd3+ content. As for the thermo-optical properties of yttrium calcium borate, they are comparable to other well-known laser glasses. The obtained energy transfer microparameters and the weak dependence of η on the Nd3+ concentration with a high optimum Nd3+ concentration put this system as a strong candidate for photonics applications.

  16. Effect of co-doped SnO{sub 2} nanoparticles on photoluminescence of cu-doped potassium lithium borate glass

    SciTech Connect

    Namma, Haydar Aboud; Wagiran, H.; Hussin, R.; Ariwahjoedi, B.

    2012-09-26

    The SnO{sub 2} co-doped lithium potassium borate glasses doped with 0.05, 0.10, 0.25 and 0.50 mol% of Cu were synthesized by the melt quenching technique. The SnO{sub 2} co-dope was added to the compounds in the amounts of 0.05, 0.10, and 0.20 mol%. The photoluminescent spectrum for different concentrations of copper was studied. It was observed that the intensity of blue emission (450, 490 nm) varies with concentration mol%. In addition, with different concentration of SnO{sub 2} to 0.10 mol% Cu, the influence of the luminescence has been observed to enhance intensity and shifted to blue and red (490, 535 nm) emissions.

  17. Structural investigation and electron paramagnetic resonance of vanadyl doped alkali niobium borate glasses.

    PubMed

    Agarwal, A; Sheoran, A; Sanghi, S; Bhatnagar, V; Gupta, S K; Arora, M

    2010-03-01

    Glasses with compositions xNb(2)O(5).(30-x)M(2)O.69B(2)O(3) (where M=Li, Na, K; x=0, 4, 8 mol%) doped with 1 mol% V(2)O(5) have been prepared using normal melt quench technique. The IR transmission spectra of the glasses have been studied over the range 400-4000 cm(-1). The changes caused by the addition of Nb(2)O(5) on the structure of these glasses have been reported. The electron paramagnetic resonance spectra of VO(2+) ions in these glasses have been recorded in X-band (9.14 GHz) at room temperature (300 K). The spin Hamiltonian parameters, dipolar hyperfine coupling parameter and Fermi contact interaction parameter have been calculated. It is observed that the resultant resonance spectra contain hyperfine structures (hfs) due to V(4+) ions which exist as VO(2+) ions in octahedral coordination with a tetragonal compression in the present glasses. The tetragonality of V(4+)O(6) complex decreases with increasing concentration of Nb(2)O(5). The 3d(xy) orbit contracts with increase in Nb(2)O(5):M(2)O ratio. Values of the theoretical optical basicity, Lambda(th), have also been reported.

  18. Luminescent properties of lithium-phosphate-borate glasses doped with Tb3+/ Eu3+ ions

    NASA Astrophysics Data System (ADS)

    Valiev, D. T.; Stepanov, S. A.; Cong, Liu

    2016-02-01

    The luminescence of Li2O-B2O3-P2O5-CaF2 scintillation glass doped Tb3+, Eu3+ under different types of excitation sources are investigated. Changing the europium concentration of 0.5 to 1 wt% leads changes in luminescence intensity of Tb3+ ions. The luminescence spectrum of the Tb3+ ions are depend on the concentration of Eu3+. It was found, that the luminescence decay kinetics of terbium ion in the band 543 nm depending on the concentration of europium and from type of excitation. The difference in the nature of the luminescence decay kinetics of glasses under pulsed photo- and electronic excitation discussed.

  19. Random lasing in Eu³⁺ doped borate glass-ceramic embedded with Ag nanoparticles under direct three-photon excitation.

    PubMed

    Xu, Xuhui; Zhang, Wenfei; Jin, Limin; Qiu, Jianbei; Yu, Siu Fung

    2015-10-21

    We report the observation of random lasing from Eu(3+) doped borate glass ceramic films embedded with Ag nanoparticles through three-photon absorption at room temperature. Under 1179 nm ultrashort femtosecond pulse excitation, discrete sharp peaks with linewidth ∼0.4 nm emerge randomly from a broad emission band with peak wavelength at ∼612 nm. In addition, the number of sharp peaks increases with the increase of excitation power. We also show that the emission spectrum varies with different observation angles and the corresponding lasing threshold is dependent on the excitation area. Hence, we verify unambiguously that the Eu(3+) doped borate glass ceramic film supports random lasing action via three-photon absorption excitation. In addition, Ag nanoparticles, which act as light scatterers, allow the formation of random microcavities inside the bulk film.

  20. Crystallization of lithium borate glasses

    NASA Technical Reports Server (NTRS)

    Goktas, A. A.; Neilson, G. F.; Weinberg, M. C.

    1992-01-01

    The glass-forming ability and crystallization behavior of lithium borate compositions, in the diborate-to-metaborate-range, were studied. In particular, the nature and sequence of formation of crystalline phases and the tendency toward devitrification were investigated as functions of temperature, thermal history and batch composition. It was found that the sequence of crystalline phase formation was sensitive to all of the three latter factors, and it was observed that under certain conditions metastable defect structures of the metaborate can appear.

  1. Effect of SiO2 content on the thermal stability and spectroscopic properties of Er/Yb co-doped tellurite borate glasses

    NASA Astrophysics Data System (ADS)

    Xu, Tiefeng; Zhang, Xudong; Dai, Shixun; Nie, Qiuhua; Shen, Xiang; Zhang, Xianghua

    2007-02-01

    Er/Yb co-doped (85-x) TeO2- 15B2O3- xSiO2 (TBS x=0, 5, 10, 15, 20 mol%) glasses had been prepared. Effect of SiO2 content on the thermal stability and spectroscopic properties of Er/Yb co-doped tellurite borate glasses have been investigated. With SiO2 content increasing from 0 to 20 mol%, the Tg and Tx, the fluorescence full width at half maximum (FWHM), the peak of stimulated emission cross-section ( σpeak), the measured lifetime ( τm) and quantum efficiency ( η) change from 398C, 530C, 75 nm, 5.7×10-21 cm2, 1.84 ms, 56.4% to 419C, 593C, 71 nm, 7.5×10-21 cm2, 2.38 ms, 70.6%, respectively. The results indicate that for Er/Yb co-doped tellurite borate glasses, introducing a suitable amount of SiO2 content is helpful for the improvement of thermal stability and the incremental of the lifetime of I13/24 level and quantum efficiency of Er:I13/24→I15/24 transition, while keeping the FWHM relatively large.

  2. Physical and electrical properties of copper oxide doped bismuth borate glasses

    NASA Astrophysics Data System (ADS)

    Dhiman, R. L.; Kundu, Virender Singh; Arora, Susheel; Maan, A. S.

    2013-06-01

    The role of CuO on the physical and electrical properties in x CuO.(25-x)Bi2O3.75B2O3;(5≤x≤20) glass system has been investigated. The glasses were prepared by normal melt quench technique. The density and molar volume of the glasses decreases with increase in CuO (mol %). The dc conductivity was measured in the temperature range 413-513 K. The conduction mechanism in these glasses was discussed in terms of small polaron hopping (SPH) theory proposed by Mott. The activation energy is found to decrease with increasing copper oxide content. The dc conductivity increases with increase in CuO content and ranging from 6.02×10-12 (Ωm)-1 to 1.096×10-10 (Ωm)-1 at 450K.

  3. Structural study and DC conductivity of vanadyl doped zinc lithium borate glasses

    SciTech Connect

    Seema; Khasa, S. Dahiya, M. S.; Yadav, Arti; Agarwal, A.; Dahiya, S.

    2015-06-24

    Glasses with composition xZnO⋅(30 − x)⋅Li{sub 2}O⋅70B{sub 2}O{sub 3} containing 2 mol% of V{sub 2}O{sub 5} (x = 0, 2, 5, 7 and 10) were prepared by standard melt-quench technique. The amorphous nature of the glass samples was confirmed by using x-ray diffraction. The structural changes in these glasses have been investigated by employing IR spectroscopy in the mid-IR range. The infrared spectroscopic analysis confirms the presence of both triangular and tetraheldral coordinated boron units and absence of boroxol ring. It also shows that metal-oxide vibrations are present which are due to the bonding of lithium and zinc ions with oxygen. The dc conductivity was measured in the temperature range 353-523 K. The dc conductivity results show that conductivity decreases and activation energy increases when Li{sub 2}O is replaced by ZnO, keeping the concentration of B{sub 2}O{sub 3} constant. Decrease in conductivity and increase in activation energy shows that addition of ZnO to the glass matrix shows a “blocking effect” on the overall mobility of alkali ions, but at higher concentration the hopping effect was also observed.

  4. Optical absorption of gamma-irradiated lithium-borate glasses doped with different transition metal oxides

    NASA Astrophysics Data System (ADS)

    Marzouk, S. Y.; Elalaily, N. A.; Ezz-Eldin, F. M.; Abd-Allah, W. M.

    2006-06-01

    We have investigated the effect of gamma irradiation on the optical properties of Li 2O-B 2O 3 containing two concentrations (0.2 or 0.5 g) of each one of the following transition metals, V, Mn, Fe or Ni oxide glass samples. We studied the impacts of gamma irradiation in terms of the mechanism by which radiation-induced defects are generated. A resolution of the observed absorption spectra showed several bands which were induced by photo-reduction or photo-oxidation assumed to take place by photo-chemical reaction according to the type of transition metal oxide (TMO). Small deviations of these induced bands characteristic of the glass constituents were observed and explained in terms of the physical properties, in relation to different oxidation states of TMO in the glass matrix. The series Mn 2+, Fe 2+ and Ni 2+ ions shows a trend of increased photo-oxidation with increasing electronegativity or decreasing mass of the ions. The prepared samples were studied in terms of their dosimetric characteristics: calibration curves from 1.0524 to 42.096 kGy and fading at (25 and 50 °C). Thermal bleaching of irradiated glass was found to permit the reduction of the larger part of TMO ions in Li 2O-B 2O 3. Also, the results showed that the degeneration of the induced bands was faster at 50 than at 25 °C. The optical energy gap Eg was found to decrease with the increase of the radiation dose, and it is suggested that the mechanism of optical transition is forbidden by indirect transition.

  5. Structural and physical properties of vanadium doped copper bismuth borate glasses

    SciTech Connect

    Dhiman, R. L.; Kundu, Virender Singh; Arora, Susheel; Maan, A. S.

    2013-02-05

    The structural and physical properties of xCuO(30-x)Bi{sub 2}O{sub 3}-70B{sub 2}O{sub 3}; x= 0, 5, 10, 15, 20 and 25 mol % with 2 mol %V{sub 2}O{sub 5} glasses prepared by normal melt quench technique have been investigated by means of FT-IR and physical measurement techniques. With the addition of copper oxide (x{<=} 10 mol%), the frequency bands in the higher region shift towards lower wave number, suggest the conversion of BO{sub 3} to BO{sub 4} structural units, which in turn give rise to the formation of Non Bridging Oxygen's (NBOs). For further increase in CuO (i.e. for x{>=} 10 mol %), the frequency bands shift towards higher wave number, indicate the formation of Bridging Oxygen's (BOs). The FTIR analysis reveals that the present glass system is based on the BiO{sub 3} pyramidal, BiO{sub 6} octahedral units and also on BO{sub 3} and BO{sub 4} structural units. The systematic variation in density and molar volume in these glasses indicates the effect of CuO substitution.

  6. Wound dressings composed of copper-doped borate bioactive glass microfibers stimulate angiogenesis and heal full-thickness skin defects in a rodent model.

    PubMed

    Zhao, Shichang; Li, Le; Wang, Hui; Zhang, Yadong; Cheng, Xiangguo; Zhou, Nai; Rahaman, Mohamed N; Liu, Zhongtang; Huang, Wenhai; Zhang, Changqing

    2015-01-01

    There is a need for better wound dressings that possess the requisite angiogenic capacity for rapid in situ healing of full-thickness skin wounds. Borate bioactive glass microfibers are showing a remarkable ability to heal soft tissue wounds but little is known about the process and mechanisms of healing. In the present study, wound dressings composed of borate bioactive glass microfibers (diameter = 0.4-1.2 μm; composition 6Na2O, 8K2O, 8MgO, 22CaO, 54B2O3, 2P2O5; mol%) doped with 0-3.0 wt.% CuO were created and evaluated in vitro and in vivo. When immersed in simulated body fluid, the fibers degraded and converted to hydroxyapatite within ∼7 days, releasing ions such as Ca, B and Cu into the medium. In vitro cell culture showed that the ionic dissolution product of the fibers was not toxic to human umbilical vein endothelial cells (HUVECs) and fibroblasts, promoted HUVEC migration, tubule formation and secretion of vascular endothelial growth factor (VEGF), and stimulated the expression of angiogenic-related genes of the fibroblasts. When used to treat full-thickness skin defects in rodents, the Cu-doped fibers (3.0 wt.% CuO) showed a significantly better capacity to stimulate angiogenesis than the undoped fibers and the untreated defects (control) at 7 and 14 days post-surgery. The defects treated with the Cu-doped and undoped fibers showed improved collagen deposition, maturity and orientation when compared to the untreated defects, the improvement shown by the Cu-doped fibers was not markedly better than the undoped fibers at 14 days post-surgery. These results indicate that the Cu-doped borate glass microfibers have a promising capacity to stimulate angiogenesis and heal full-thickness skin defects. They also provide valuable data for understanding the role of the microfibers in healing soft tissue wounds.

  7. Wound dressings composed of copper-doped borate bioactive glass microfibers stimulate angiogenesis and heal full-thickness skin defects in a rodent model.

    PubMed

    Zhao, Shichang; Li, Le; Wang, Hui; Zhang, Yadong; Cheng, Xiangguo; Zhou, Nai; Rahaman, Mohamed N; Liu, Zhongtang; Huang, Wenhai; Zhang, Changqing

    2015-01-01

    There is a need for better wound dressings that possess the requisite angiogenic capacity for rapid in situ healing of full-thickness skin wounds. Borate bioactive glass microfibers are showing a remarkable ability to heal soft tissue wounds but little is known about the process and mechanisms of healing. In the present study, wound dressings composed of borate bioactive glass microfibers (diameter = 0.4-1.2 μm; composition 6Na2O, 8K2O, 8MgO, 22CaO, 54B2O3, 2P2O5; mol%) doped with 0-3.0 wt.% CuO were created and evaluated in vitro and in vivo. When immersed in simulated body fluid, the fibers degraded and converted to hydroxyapatite within ∼7 days, releasing ions such as Ca, B and Cu into the medium. In vitro cell culture showed that the ionic dissolution product of the fibers was not toxic to human umbilical vein endothelial cells (HUVECs) and fibroblasts, promoted HUVEC migration, tubule formation and secretion of vascular endothelial growth factor (VEGF), and stimulated the expression of angiogenic-related genes of the fibroblasts. When used to treat full-thickness skin defects in rodents, the Cu-doped fibers (3.0 wt.% CuO) showed a significantly better capacity to stimulate angiogenesis than the undoped fibers and the untreated defects (control) at 7 and 14 days post-surgery. The defects treated with the Cu-doped and undoped fibers showed improved collagen deposition, maturity and orientation when compared to the untreated defects, the improvement shown by the Cu-doped fibers was not markedly better than the undoped fibers at 14 days post-surgery. These results indicate that the Cu-doped borate glass microfibers have a promising capacity to stimulate angiogenesis and heal full-thickness skin defects. They also provide valuable data for understanding the role of the microfibers in healing soft tissue wounds. PMID:25890736

  8. Cooperative luminescence sensitisation and spontaneous Raman scattering in a borate glass doped with Pr{sup 3+} and Nd{sup 3+} ions

    SciTech Connect

    Chanturiya, G F; Kutaladze, L M; Tatarashvili, R A; Shchegolikhin, Aleksandr N

    2004-04-30

    Cooperative sensitisation of luminescence of Nd{sup 3+} ions at the {sup 4}F{sub 3/2} {yields} {sup 4}I{sub 13/2}, {sup 4}I{sub 9/2} transitions by Pr{sup 3+} ions was observed in a borate glass doped with Pr{sup 3+}-Nd{sup 3+} ion pairs. The luminescence was excited by a 800-mW, 1.064-{mu}m Nd{sup 3+}:YAG laser. Simultaneously, spontaneous Raman scattering was observed in glasses containing Pr{sup 3+}-Nd{sup 3+} ion pairs or only Pr{sup 3+} ions. The Stokes shift from the 9398-cm{sup -1} excitation line is 794 cm{sup -1}. The mechanism of nonradiative energy transfer is discussed. (laser applications and other topics in quantum electronics)

  9. Bioactive borate glass coatings for titanium alloys.

    PubMed

    Peddi, Laxmikanth; Brow, Richard K; Brown, Roger F

    2008-09-01

    Bioactive borate glass coatings have been developed for titanium and titanium alloys. Glasses from the Na(2)O-CaO-B(2)O(3) system, modified by additions of SiO(2), Al(2)O(3), and P(2)O(5), were characterized and compositions with thermal expansion matches to titanium were identified. Infrared and X-ray diffraction analyses indicate that a hydroxyapatite surface layer forms on the borate glasses after exposure to a simulated body fluid for 2 weeks at 37 degrees C; similar layers form on 45S5 Bioglass((R)) exposed to the same conditions. Assays with MC3T3-E1 pre-osteoblastic cells show the borate glasses exhibit in vitro biocompatibility similar to that of the 45S5 Bioglass((R)). An enameling technique was developed to form adherent borate glass coatings on Ti6Al4V alloy, with adhesive strengths of 36 +/- 2 MPa on polished substrates. The results show these new borate glasses to be promising candidates for forming bioactive coatings on titanium substrates.

  10. Comparative study of ion conducting pathways in borate glasses

    SciTech Connect

    Hall, Andreas; Swenson, Jan; Adams, Stefan

    2006-11-01

    The conduction pathways in metal-halide doped silver, lithium, and sodium diborate glasses have been examined by bond valence analysis of reverse Monte Carlo (RMC) produced structural models of the glasses. Although all glass compositions have basically the same short-range structure of the boron-oxygen network, it is evident that the intermediate-range structure is strongly dependent on the type of mobile ion. The topography of the pathways and the coordination of the pathway sites differ distinctly between the three glass systems. The mobile silver ions in the AgI-doped glass tend to be mainly iodine-coordinated and travel in homogeneously distributed pathways located in salt-rich channels of the borate network. In the NaCl-doped glass, there is an inhomogeneous spatial distribution of pathways that reflects the inhomogeneous introduction of salt ions into the glass. However, since the salt clusters are not connected, no long-range conduction pathways are formed without including also oxygen-rich regions. The pathways in the LiCl-doped glass are slightly more evenly distributed compared to the NaCl-doped glass (but not as ordered as in the AgI-doped glass), and the regions of mainly oxygen-coordinated pathway sites are of higher importance for the long-range migration. In order to more accurately investigate how these differences in the intermediate-range order of the glasses affect the ionic conductivity, we have compared the realistic structure models to more or less randomized structures. An important conclusion from this comparison is that we find no evidence that a pronounced intermediate-range order in the atomic structure or in the network of conduction pathways, as in the AgI-doped glass, is beneficial for the dc conductivity.

  11. Effect of WO 3 on the spectroscopic properties in Er 3+/Yb 3+ co-doped bismuth-borate glasses

    NASA Astrophysics Data System (ADS)

    Wang, Jun; Zhou, Yaxun; Dai, Shixun; Xu, Tiefeng; Nie, Qiuhua

    2007-11-01

    The spectroscopic properties of Er 3+/Yb 3+ co-doped Bi 2O 3-B 2O 3-WO 3 (BBW) glasses were analyzed and discussed. The effect of WO 3 content on the absorption spectra, the Judd-Ofelt parameters Ω t ( t=2, 4, 6), emission spectra and the lifetime of the 4I 13/2 level and the quantum efficiency of Er 3+: 4I 13/2→ 4I 15/2 transition were also investigated. With the substitution of WO 3 for B 2O 3, the measured lifetime of the 4I 13/2 level and the quantum efficiency of Er 3+: 4I 13/2→ 4I 15/2 transition increase from 0.98 to 1.31 ms and from 38.2% to 49.2%, respectively. The effective width of emission band and the emission cross-section both decrease slightly. And the emission spectra is analyzed via the different curve ( σe- σa) of BBW glasses, the influence of OH - is also discussed.

  12. Interfacial reactions between titanium and borate glass

    SciTech Connect

    Brow, R.K.; Saha, S.K.; Goldstein, J.I.

    1992-12-31

    Interfacial reactions between melts of several borate glasses and titanium have been investigated by analytical scanning electron microscopy (SEM) and x-ray photoelectron spectroscopy (XPS). A thin titanium boride interfacial layer is detected by XPS after short (30 minutes) thermal treatments. ASEM analyses after longer thermal treatments (8--120 hours) reveal boron-rich interfacial layers and boride precipitates in the Ti side of the interface.

  13. Borates

    USGS Publications Warehouse

    Angulo, M.A.

    2011-01-01

    The article discusses the latest developments in the borates industry, particularly in the U.S., as of June 2011. It claims that the biggest economically feasible deposits of borates are seen in the U.S.' Mojave Desert, the Alpide belt in southern Asia and the Andean belt of South America. Turkish state-owned mining firm Eti Maden AS reported that borates were mainly used in the manufacture of glass, ceramics, fertilizer and detergent in 2009.

  14. Towards modeling gadolinium-lead-borate glasses

    SciTech Connect

    Rada, S.; Ristoiu, T.; Rada, M.; Coroiu, I.; Maties, V.; Culea, E.

    2010-01-15

    Infrared spectra of gadolinium-lead-borate glasses of the xGd{sub 2}O{sub 3}.(100 - x)[3B{sub 2}O{sub 3}.PbO] system, where x = 0, 5, 10, 15, 25, 35 and 50 mol.%, have been recorded to explore the role of content of gadolinium ions behaving as glass modifier. The FTIR spectroscopy data for the xGd{sub 2}O{sub 3}.(1 - x)[3B{sub 2}O{sub 3}.PbO] glasses show the structural role of lead ions as a network-formers and of the gadolinium ions network modifiers. Adding of the rare earth ion up to 35 mol.% into the glass matrix, the IR bands characteristic to the studied glasses become sharper and more pronounced. Structural changes, as recognized by analyzing band shapes of IR spectra, revealed that Gd{sub 2}O{sub 3} causes a change from the continuous borate network to the continuous lead-borate network interconnected through Pb-O-B and B-O-B bridges and the transformation of some tetrahedral [BO{sub 4}] units into trigonal [BO{sub 3}] units. Then, gadolinium ions have affinity towards [BO{sub 3}] structural units which contain non-bridging oxygens necessary for the charge compensation because the more electronegative [BO{sub 3}] structural units were implied in the formation of B-O-Gd bonds and the transformation of glass network into a glass ceramic. We propose a possible structural model of building blocks for the formation of continuous random 3B{sub 2}O{sub 3}.PbO network glass used by density functional theory (DFT) calculations. DFT calculations show that lead atoms occupy three different sites in the proposed model. The first is coordinated with six oxygen atoms forming distorted octahedral geometries. The second lead atom has an octahedral oxygen environment and the five longer Pb-O bonds are considered as participating in the metal coordination scheme. The third lead atom has ionic character. In agreement with the results offered by the experimental FTIR data, the theoretical IR data confirm that our proposed structure is highly possible.

  15. Mixed polaronic-ionic conduction in lithium borate glasses and glass-ceramics containing copper oxide

    NASA Astrophysics Data System (ADS)

    Khalil, M. M. I.

    2007-03-01

    The effect of electric field strength on conduction in lithium borate glasses doped with CuO with different concentration was studied and the value of the jump distance of charge carrier was calculated. The conductivity measurements indicate that the conduction is due to non-adiabatic hopping of polarons and the activation energies are found to be temperature and concentration dependent. Lithium borate glasses are subjected to carefully-programmed thermal treatments which cause the nucleation and growth of crystalline phases. X-ray diffraction analysis confirmed the amorphous nature for the investigated glass sample and the formation of crystalline phase for annealed samples at 650 °C. The main separated crystalline phase is Li2B8O13. The scanning electron micrographs of some selected glasses showed a significant change in the morphology of the films investigated due to heat treatment of the glass samples. It was found that the dc-conductivity decreases with an increase of the HT temperature. The decrease of dc conductivity, with an increase of the HT temperature, can be related to the decrease in the number of free ions in the glass matrix. There is deviation from linearity at high temperature regions in the logσ-1/T plots for all investigated doped samples at a certain temperature at which the transition from polaronic to ionic conduction occurs. The hopping of small polarons is dominant at low temperatures, whereas the hopping of Li+ ions dominates at high temperatures.

  16. Angiogenic effects of borate glass microfibers in a rodent model.

    PubMed

    Lin, Yinan; Brown, Roger F; Jung, Steven B; Day, Delbert E

    2014-12-01

    The primary objective of this research was to evaluate the use of bioactive borate-based glass microfibers for angiogenesis in soft tissue repair applications. The effect of these fibers on growth of capillaries and small blood vessels was compared to that of 45S5 silica glass microfibers and sham implant controls. Compressed mats of three types of glass microfibers were implanted subcutaneously in rats and tissues surrounding the implant sites histologically evaluated 2-4 weeks post surgery. Bioactive borate glass 13-93B3 supplemented with 0.4 wt % copper promoted extensive angiogenesis as compared to silica glass microfibers and sham control tissues. The angiogenic responses suggest the copper-containing 13-93B3 microfibers may be effective for treating chronic soft tissue wounds. A second objective was to assess the possible systemic cytotoxicity of dissolved borate ions and other materials released from implanted borate glass microfibers. Cytotoxicity was assessed via histological evaluation of kidney tissue collected from animals 4 weeks after subcutaneously implanting high amounts of the borate glass microfibers. The evaluation of the kidney tissue from these animals showed no evidence of chronic histopathological changes in the kidney. The overall results indicate the borate glass microfibers are safe and effective for soft tissue applications.

  17. Angiogenic effects of borate glass microfibers in a rodent model.

    PubMed

    Lin, Yinan; Brown, Roger F; Jung, Steven B; Day, Delbert E

    2014-12-01

    The primary objective of this research was to evaluate the use of bioactive borate-based glass microfibers for angiogenesis in soft tissue repair applications. The effect of these fibers on growth of capillaries and small blood vessels was compared to that of 45S5 silica glass microfibers and sham implant controls. Compressed mats of three types of glass microfibers were implanted subcutaneously in rats and tissues surrounding the implant sites histologically evaluated 2-4 weeks post surgery. Bioactive borate glass 13-93B3 supplemented with 0.4 wt % copper promoted extensive angiogenesis as compared to silica glass microfibers and sham control tissues. The angiogenic responses suggest the copper-containing 13-93B3 microfibers may be effective for treating chronic soft tissue wounds. A second objective was to assess the possible systemic cytotoxicity of dissolved borate ions and other materials released from implanted borate glass microfibers. Cytotoxicity was assessed via histological evaluation of kidney tissue collected from animals 4 weeks after subcutaneously implanting high amounts of the borate glass microfibers. The evaluation of the kidney tissue from these animals showed no evidence of chronic histopathological changes in the kidney. The overall results indicate the borate glass microfibers are safe and effective for soft tissue applications. PMID:24677635

  18. Variation of photoluminescence features in Pr{sup 3+} doped lithium-fluoro-borate glass by changing different modifier oxides (MgO, CaO, CdO and PbO)-Judd-Ofelt theory application

    SciTech Connect

    Balakrishna, A.; Rajesh, D.; Babu, S.; Ratnakaram, Y. C.

    2015-06-24

    Pr{sup 3+} (1.0 mol%) doped different modifier oxide based six lithium-fluoro-borate glasses with chemical composition of 49Li{sub 2}B{sub 4}O{sub 7}-20BaF{sub 2}-10NaF-20MO (where M= Mg, Ca, Cd and Pb), 49Li{sub 2}B{sub 4}O{sub 7}-20BaF{sub 2}-10NaF-10MgO-10CaO and 49Li{sub 2}B{sub 4}O{sub 7}-20BaF{sub 2}-10NaF-10CdO-10PbO were prepared by conventional melt quenching technique. Judd-Ofelt theory has been applied for evaluating the Judd-Ofelt intensity parameters for Pr{sup 3+} ion in these glass compositions and are in turn to used to predict radiative properties such as radiative transition probabilities (A{sub T}), branching ratios (β) and stimulated emission cross-section (σ{sub P}). Stimulated emission cross-section (σ{sub p}) of prominent emission transitions, {sup 3}P{sub 0}→{sup 3}H{sub 4} and {sup 1}D{sub 2}→{sup 3}H{sub 4} of Pr{sup 3+} ion in all lithium-fluoro-borate glasses were calculated. Among all the emission transitions, {sup 3}P{sub 0}→{sup 3}H{sub 4} posseses higher branching ratio and stimulated emission cross-section in Mg-Ca glass, which leads to the best laser excitation at 487 nm wavelength.

  19. CADMIUM-RARE EARTH BORATE GLASS AS REACTOR CONTROL MATERIAL

    DOEpatents

    Ploetz, G.L.; Ray, W.E.

    1958-11-01

    A reactor control rod fabricated from a cadmiumrare earth-borate glass is presented. The rare earth component of this glass is selected from among those rare earths having large neutron capture cross sections, such as samarium, gadolinium or europium. Partlcles of this glass are then dispersed in a metal matrix by standard powder metallurgy techniques.

  20. Impact of vanadium ions in barium borate glass.

    PubMed

    Abdelghany, A M; Hammad, Ahmed H

    2015-02-25

    Combined optical and infrared spectral measurements of prepared barium borate glasses containing different concentrations of V2O5 were carried out. Vanadium containing glasses exhibit extended UV-visible (UV/Vis.) bands when compared with base binary borate glass. UV/Vis. spectrum shows the presence of an unsymmetrical strong UV broad band centered at 214 nm attributed to the presence of unavoidable trace iron impurities within the raw materials used for the preparation of such glass. The calculated direct and indirect optical band gaps are found to decrease with increasing the vanadium content (2.9:137 for indirect and 3.99:2.01 for direct transition). This change was discussed in terms of structural changes in the glass network. Infrared absorption spectra of the glasses reveal the appearance of both triangular and tetrahedral borate units. Electron spin resonance analyses indicate the presence of unpaired species in sufficient quantity to be identified and to confirm the spectral data.

  1. Synthesis and characterization of rare-earth doped SrBi{sub 2}Nb{sub 2}O{sub 9} phase in lithium borate based nanocrystallized glasses

    SciTech Connect

    Harihara Venkataraman, B.; Fujiwara, Takumi; Komatsu, Takayuki

    2009-06-15

    Glass composites comprising of un-doped and samarium-doped SrBi{sub 2}Nb{sub 2}O{sub 9} nanocrystallites are fabricated in the glass system 16.66SrO-16.66[(1-x)Bi{sub 2}O{sub 3}-xSm{sub 2}O{sub 3}]-16.66Nb{sub 2}O{sub 5}-50Li{sub 2}B{sub 4}O{sub 7} (0<=x<=0.5, in mol%) via the melt quenching technique. The glassy nature of the as-quenched samples is established by differential thermal analyses. Transmission electron microscopic studies reveal the presence of about 15 nm sized spherical crystallites of the fluorite-like SrBi{sub 1.9}Sm{sub 0.1}Nb{sub 2}O{sub 9} phase in the samples heat treated at 530 deg. C. The formation of layered perovskite-type un-doped and samarium-doped SrBi{sub 2}Nb{sub 2}O{sub 9} nanocrystallites with an orthorhombic structure through the intermediate fluorite phase is confirmed by X-ray powder diffraction and micro-Raman spectroscopic studies. The influence of samarium doping on the lattice parameters, lattice distortions, and the Raman peak positions of SrBi{sub 2}Nb{sub 2}O{sub 9} perovskite phase is clarified. The dielectric constants of the perovskite SrBi{sub 2}Nb{sub 2}O{sub 9} and SrBi{sub 1.9}Sm{sub 0.1}Nb{sub 2}O{sub 9} nanocrystals are relatively larger than those of the corresponding fluorite-like phase and the precursor glass. - Graphical Abstract: This figure shows the XRD patterns at room temperature for the as-quenched and heat treated samples in Sm{sub 2}O{sub 3}-doped (x=0.1) glass. Based on these results, it is concluded that the formation of samarium-doped perovskite SBN phase takes place via an intermediate fluorite-like phase in the crystallization of this glass.

  2. Topological phases in Ba-Borate glasses

    NASA Astrophysics Data System (ADS)

    Holbrook, Chad; Czaja, Andrew; Boolchand, Punit

    2015-03-01

    Twelve compositions in the (BaO)x(B2O3)100-x pseudo binary, in the 15% Borates2. Modes near 808 cm-1, 770 cm-1, 740 cm-1 and 705 cm-1 are observed, and identified with breathing modes of pure and mixed rings from characteristic structural groupings2. These preliminary results suggest that glasses at x <24% are in the stressed-rigid phase, in the 24% 30% in the flexible phase. Supported by NSF Grant DMR 08-53957.

  3. Low-energy vibrational dynamics of cesium borate glasses.

    PubMed

    Crupi, C; D'Angelo, G; Vasi, C

    2012-06-01

    Low-temperature specific heat and inelastic light scattering experiments have been performed on a series of cesium borate glasses and on a cesium borate crystal. Raman measurements on the crystalline sample have revealed the existence of cesium rattling modes in the same frequency region where glasses exhibit the boson peak (BP). These localized modes are supposed to overlap with the BP in cesium borate glasses affecting its magnitude. Their influence on the low frequency vibrational dynamics in glassy samples has been considered, and their contribution to the specific heat has been estimated. Evidence for a relation between the changes of the BP induced by the increased amount of metallic oxide and the variations of the elastic medium has been provided.

  4. Infrared and Raman spectroscopic studies on alkali borate glasses: evidence of mixed alkali effect.

    PubMed

    Padmaja, G; Kistaiah, P

    2009-03-19

    A lithium-potassium-borate glass system containing manganese and iron cations has been thoroughly investigated in order to obtain information about the mixed alkali effect and the structural role of both the manganese and iron in such glass hosts. Mixed alkali borate glasses of the (30 - x)Li(2)O - xK(2)O - 10CdO/ZnO - 59B(2)O(3) (x = 0, 10, 15, 20, and 30) doped with 1MnO(2)/1Fe(2)O(3) system were prepared by a melt quench technique. The amorphous phase of the prepared glass samples was confirmed from their X-ray diffraction. The spectroscopic properties of glass samples were studied using infrared (IR) and Raman spectroscopic techniques. The density of all the prepared glasses was measured using Archimedes principle. Molar volumes were estimated from the density data. IR spectra of these glasses revealed a dramatic variation of three- and four-coordinated boron structures as a function of mixed alkali concentration. The vibrations due to Li-O, K-O, and MnO(4)/FeO(4) arrangements are consistent in all the compositions and show a nonlinear variation in the intensity with alkali content. Raman spectra of different alkali combinations with CdO and ZnO present drastic changes in the intensity of various Raman bands. The observation of disappearance and reappearance of IR and Raman bands as a function of various alkali concentrations is an important result pertaining to the mixed alkali effect in borate glasses. Acting as complementary spectroscopic techniques, both types of measurements, IR and Raman, revealed that the network structure of the studied glasses is mainly based on BO(3) and BO(4) units placed in different structural groups, the BO(3) units being dominant. The measured IR and Raman spectra of different glasses are used to clarify the optical properties of the present glasses correlating them with their structure and composition. PMID:19235995

  5. Optical properties of down-shifting barium borate glass for CdTe solar cells

    NASA Astrophysics Data System (ADS)

    Loos, Sebastian; Steudel, Franziska; Ahrens, Bernd; Schweizer, Stefan

    2015-03-01

    CdTe thin film solar cells have a poor response in the ultraviolet and blue spectral range, mainly due to absorption and thermalization losses in the CdS buffer layer. To overcome this efficiency drop in the short wavelength range trivalent rare-earth doped barium borate glass is investigated for its potential as frequency down-shifting cover glass on top of the cell. The glass is doped with either Tb3+ or Eu3+ up to a level of 2.5 at.% leading to strong absorption in the ultraviolet/blue spectral range. Tb3+ shows intense emission bands in the green spectral range while Eu3+ emits in the orange/red spectral range. Based on rare-earth absorption and luminescence quantum efficiency the possible gain in short-circuit current density is calculated.

  6. Effect of copper oxide on structure and physical properties of lithium lead borate glasses

    NASA Astrophysics Data System (ADS)

    Kashif, I.; Ratep, A.

    2015-09-01

    Copper-doped Lead lithium borate glass samples with the composition of (35- x) Pb3O4- xCuO-65Li2B4O7, where x = 5, 10, 15 or 20 mol%, have been prepared by melt quenching technique. Glass-forming ability, density, electrical conductivity, magnetic susceptibility and structural properties of lead lithium borate glasses have been investigated. IR spectroscopic data show that the copper ions play the role of glass modifier. Addition of CuO influences BO3 ↔ BO4 conversion. Density is expressed in terms of the structural modifications that take place in glass matrix. The increase in Tg reflects an increase in bond strength, and samples obtain more rigid glass structure. Electrical conductivity and magnetic susceptibility χ data show a variable behavior with the increase in the copper content in two valance states Cu+ and Cu+2. In addition, optical properties depend on the change of the role of copper ions in the samples' structure. Optical energy band gap E opt and Urbach energy E tail are determined. The increase in E opt and UV cutoff with an increase in CuO content is due to the decrease in non-bridging oxygen concentration. The decrease in E tail at higher concentrations is attributed to the copper ion accumulation in the interstitial positions and to the formation of orthoborate groups. These samples are suitable for the green light longpass filters.

  7. Third order nonlinear optical properties of bismuth zinc borate glasses

    SciTech Connect

    Shanmugavelu, B.; Ravi Kanth Kumar, V. V.; Kuladeep, R.; Narayana Rao, D.

    2013-12-28

    Third order nonlinear optical characterization of bismuth zinc borate glasses are reported here using different laser pulse durations. Bismuth zinc borate glasses with compositions xBi{sub 2}O{sub 3}-30ZnO-(70-x) B{sub 2}O{sub 3} (where x = 30, 35, 40, and 45 mol. %) have been prepared by melt quenching method. These glasses were characterized by Raman, UV-Vis absorption, and Z scan measurements. Raman and UV-Vis spectroscopic results indicate that non-bridging oxygens increase with increase of bismuth content in the glass. Nonlinear absorption and refraction behavior in the nanosecond (ns), picosecond (ps), and femtosecond (fs) time domains were studied in detail. Strong reverse saturable absorption due to dominant two-photon absorption (TPA) was observed with both ps and fs excitations. In the case of ns pulse excitations, TPA and free-carrier absorption processes contribute for the nonlinear absorption. Two-photon absorption coefficient (β) and the absorption cross section due to free carriers (σ{sub e}) are estimated by theoretical fit of the open aperture Z-scan measurements and found to be dependent on the amount of bismuth oxide in the glass composition. In both ns and fs regimes the sign and magnitude of the third order nonlinearity are evaluated, and the optical limiting characteristics are also reported.

  8. Raman and Infrared Spectroscopy of Yttrium Aluminum Borate Glasses and Glass-ceramics

    NASA Technical Reports Server (NTRS)

    Bradley, J.; Brooks, M.; Crenshaw, T.; Morris, A.; Chattopadhyay, K.; Morgan, S.

    1998-01-01

    Raman spectra of glasses and glass-ceramics in the Y2O3-Al2O3-B2O3 system are reported. Glasses with B2O3 contents ranging from 40 to 60 mole percent were prepared by melting 20 g of the appropriate oxide or carbonate powders in alumina crucibles at 1400 C for 45 minutes. Subsequent heat treatments of the glasses at temperatures ranging from 600 to 800 C were performed in order to induce nucleation and crystallization. It was found that Na2CO3 added to the melt served as a nucleating agent and resulted in uniform bulk crystallization. The Raman spectra of the glasses are interpreted primarily in terms of vibrations of boron - oxygen structural groups. Comparison of the Raman spectra of the glass-ceramic samples with spectra of aluminate and borate crystalline materials reveal that these glasses crystallize primarily as yttrium aluminum borate, YAl3(BO3)4.

  9. Optical and FT Infrared spectral studies of vanadium ions in cadmium borate glass and effects of gamma irradiation.

    PubMed

    AbdelAziz, T D; EzzElDin, F M; El Batal, H A; Abdelghany, A M

    2014-10-15

    Combined optical and infrared absorption spectra of V2O5-doped cadmium borate glasses were investigated before and after gamma irradiation with a dose of 8 Mrad (=8×10(4) Gy). The undoped base cadmium borate glass reveals a spectrum consisting of strong charge transfer UV absorption bands which are related to the presence of unavoidable contaminated trace iron impurities (mainly Fe(3+)). The V2O5-doped glasses reveal an extra band at 380nm and the high V2O5-content glass also shows a further band at about 420nm. The observed optical spectrum indicates the presence of vanadium ions mainly in the pentavalent state (d(0) configuration). The surplus band at 420nm shows that some trivalent vanadium ions are identified at high V2O5 content. The optical spectra of the glasses after gamma irradiation show small decrease of the intensity of the UV absorption which are interpreted by assuming the transformation of some Fe(3+) ions by photochemical reactions with the presence of high content (45mol%) of heavy massive CdO causing some shielding behavior. FT infrared absorption spectra of the glasses show vibrational bands due to collective presence of triangular and tetrahedral borate groups in their specific wavenumbers. The FTIR spectra are observed to be slightly affected by both the V2O5-dopants being present in modifying low percent or gamma irradiation due to the presence of high content heavy CdO.

  10. Optical properties of bismuth borate glasses

    NASA Astrophysics Data System (ADS)

    Oprea, Isabella-Ioana; Hesse, Hartmut; Betzler, Klaus

    2004-08-01

    Optical properties of glasses in the binary system bismuth oxide (Bi 2O 3)-boric oxide (B 2O 3) are measured for the composition range 25-65 mol% Bi 2O 3. Both, refractive indices and ultraviolet absorption edge, show an expressed dependence on composition. A generalized Sellmeier formula is derived to describe the refractive indices for the whole composition range and a wide wavelength range.

  11. Relationship between Eu{sup 3+} reduction and glass polymeric structure in Al{sub 2}O{sub 3}-modified borate glasses under air atmosphere

    SciTech Connect

    Jiao, Qing; Yu, Xue; Xu, Xuhui; Zhou, Dacheng; Qiu, Jianbei

    2013-06-15

    The reduction of Eu{sup 3+} to Eu{sup 2+} is realized efficiently in Eu{sub 2}O{sub 3}-doped borate glasses prepared under air condition by melting-quenching method. Luminescent spectra show an increasing tendency of Eu{sup 2+} emission with increasing Al{sub 2}O{sub 3} concentration in B{sub 2}O{sub 3}–Na{sub 2}O glasses. It is interesting that significant enhancement appeared of Eu{sup 2+} luminescence in the Al{sub 2}O{sub 3}-rich sample comparing to the samples of Al{sub 2}O{sub 3} less than 6 mol%. FTIR and Raman scattering measurements indicated that some new vibration modes assigned to the low-polymerized structure groups decomposed from the slight Al{sub 2}O{sub 3} dopant samples. These results demonstrated that the polymerization of the glass structure decreased with increasing incorporation of Al{sub 2}O{sub 3} into the borate glasses, linking to the efficiency of Eu{sup 3+} self-reduction in air at high temperature. - graphical abstract: A novel europium valence reduction phenomenon occurred in Al{sub 2}O{sub 3} modified borate glasses, FTIR and Raman measurements revealed that high polymeric groups were destroyed to low polymery structures with Al{sub 2}O{sub 3} addition. - Highlights: • The efficient reduction of Eu{sup 3+} to Eu{sup 2+} is observed in the B{sub 2}O{sub 3}–Na{sub 2}O glasses. • Eu{sup 2+} luminescence is significant enhanced in the Al{sub 2}O{sub 3}-rich glasses. • The introduction of Al{sub 2}O{sub 3} changed the network structure of the borate glasses. • High polymeric borate groups in the glass matrix may be destroyed to the lower ones.

  12. In vitro study of improved wound-healing effect of bioactive borate-based glass nano-/micro-fibers.

    PubMed

    Yang, Qingbo; Chen, Sisi; Shi, Honglan; Xiao, Hai; Ma, Yinfa

    2015-10-01

    Because of the promising wound-healing capability, bioactive glasses have been considered as one of the next generation hard- and soft-tissue regeneration materials. The lack of understanding of the substantial mechanisms, however, indicates the need for further study on cell-glass interactions to better interpret the rehabilitation capability. In the present work, three bioactive glass nano-/micro-fibers, silicate-based 45S5, borate-based 13-93B3 and 1605 (additionally doped with copper oxide and zinc oxide), were firstly compared for their in vitro soaking/conversion rate. The results of elemental monitoring and electron microscopic characterization demonstrated that quicker ion releasing and glass conversion occurred in borate-based fibers than that of silicate-based one. This result was also reflected by the formation speed of hydroxyapatite (HA). This process was further correlated with original boron content and surrounding rheological condition. We showed that an optimal fiber pre-soaking time (or an ideal dynamic flow rate) should exist to stimulate the best cell proliferation and migration ability. Moreover, 13-93B3 and 1605 fibers showed different glass conversion and biocompatibility properties as well, indicating that trace amount variation in composition can also influence fiber's bioactivity. In sum, our in vitro rheological module closely simulated in vivo niche environment and proved a potentially improved wound-healing effect by borate-based glass fibers, and the results shall cast light on future improvement in bioactive glass fabrication.

  13. In vitro study of improved wound-healing effect of bioactive borate-based glass nano-/micro-fibers.

    PubMed

    Yang, Qingbo; Chen, Sisi; Shi, Honglan; Xiao, Hai; Ma, Yinfa

    2015-10-01

    Because of the promising wound-healing capability, bioactive glasses have been considered as one of the next generation hard- and soft-tissue regeneration materials. The lack of understanding of the substantial mechanisms, however, indicates the need for further study on cell-glass interactions to better interpret the rehabilitation capability. In the present work, three bioactive glass nano-/micro-fibers, silicate-based 45S5, borate-based 13-93B3 and 1605 (additionally doped with copper oxide and zinc oxide), were firstly compared for their in vitro soaking/conversion rate. The results of elemental monitoring and electron microscopic characterization demonstrated that quicker ion releasing and glass conversion occurred in borate-based fibers than that of silicate-based one. This result was also reflected by the formation speed of hydroxyapatite (HA). This process was further correlated with original boron content and surrounding rheological condition. We showed that an optimal fiber pre-soaking time (or an ideal dynamic flow rate) should exist to stimulate the best cell proliferation and migration ability. Moreover, 13-93B3 and 1605 fibers showed different glass conversion and biocompatibility properties as well, indicating that trace amount variation in composition can also influence fiber's bioactivity. In sum, our in vitro rheological module closely simulated in vivo niche environment and proved a potentially improved wound-healing effect by borate-based glass fibers, and the results shall cast light on future improvement in bioactive glass fabrication. PMID:26117744

  14. Synthesis and studies on microhardness of alkali zinc borate glasses

    SciTech Connect

    Subhashini, Bhattacharya, Soumalya Shashikala, H. D. Udayashankar, N. K.

    2014-04-24

    The mixed alkali effect on zinc borate glasses have been reported. The glass systems of nominal composition 10Zn+xLi{sub 2}O+yNa{sub 2}O+80B{sub 2}O{sub 3} (x = y = 0, 5, 10, 15 mol%) were prepared using standard melt quenching method. The structural, physical and mechanical properties of the samples have been studied using X-ray diffraction(XRD), density measurement and Vickers hardness measurement, respectively. A consistent increase in the density was observed, which explains the role of the modifiers (Li{sub 2}O and Na{sub 2}O) in the network modification of borate structure. The molar volume is decreasing linearly with the alkali concentration, which is attributed to the conversion of tetrahedral boron (BO{sub 4/2}){sup −} into (BO{sub 3/2}){sup −}. The microhardness studies reveals the anisotropy nature of the material. It further confirms that the samples belong to hard glass category.

  15. A study of physical and optical absorption spectra of VO2+ ions in potassium and sodium oxide borate glasses

    NASA Astrophysics Data System (ADS)

    Srinivas, G.; Ramesh, B.; Kumar, J. Siva; Shareefuddin, Md.; Chary, M. N.; Sayanna, R.

    2016-05-01

    Spectroscopic and physical properties of V2O5 doped mixed alkali borate glasses are investigated. Borate glasses containing fixed concentrations of alkaline earth oxides (MgO and BaO) and alkali oxides (K2O and Na2O) were changes and are prepared by melt quenching technique. The values of ri, rp, Rm, αm molar volume and Λth increase and oxygen packing density, density and dopant ion concentration decrease with increasing of K2O content. As a result there shall be an increase in the disorder of the glass network. The optical band gap energies, Urbach energy, boron-boron separation,refractive index, dielectric constant, electronic polarizability and reflection loss values are varies nonlinearly with the K2O content which manifests the mixed alkali effect.

  16. Borates

    USGS Publications Warehouse

    Crangle, R.D.

    2013-01-01

    Four minerals represent 90 percent of the borates used by industry worldwide — the sodium borates (tincal and kernite), calcium borate (colemanite) and the sodium-calcium borate (ulexite). Borax is a white crystalline substance, chemically known as sodium tetraborate decahydrate, and is found naturally as the mineral tincal. Boric acid is a colorless crystalline solid sold in technical, national formulary and special quality grades as granules or powder and marketed most often as anhydrous boric acid. Deposits of borates are associated with volcanic activity and arid climates, with the largest economically viable deposits located in the Mojave Desert of the United States near Boron, CA, the Alpide belt in southern Asia and the Andean belt of South America.

  17. Ytterbium-doped borate fluoride laser crystals and lasers

    DOEpatents

    Schaffers, K.I.; DeLoach, L.D.; Payne, S.A.; Keszler, D.A.

    1997-10-14

    A new class of solid state laser crystals and lasers are formed from Yb-doped borate fluoride host crystals. The general formula for the host crystals is MM{prime}(BO{sub 3})F, where M, M{prime} are monovalent, divalent aria trivalent metal cations. A particular embodiment of the invention is Yb-doped BaCaBO{sub 3}F (Yb:BCBF). BCBF and some of the related derivative crystals are capable of nonlinear frequency conversion, whereby the fundamental of the laser is converted to a longer or shorter wavelength. In this way, these new crystals can simultaneously serve as self-frequency doubling crystals and laser materials within the laser resonator. 6 figs.

  18. Ytterbium-doped borate fluoride laser crystals and lasers

    DOEpatents

    Schaffers, Kathleen I.; DeLoach, Laura D.; Payne, Stephen A.; Keszler, Douglas A.

    1997-01-01

    A new class of solid state laser crystals and lasers are formed from Yb-doped borate fluoride host crystals. The general formula for the host crystals is MM'(BO.sub.3)F, where M, M' are monovalent, divalent aria trivalent metal cations. A particular embodiment of the invention is Yb-doped BaCaBO.sub.3 F (Yb:BCBF). BCBF and some of the related derivative crystals are capable of nonlinear frequency conversion, whereby the fundamental of the laser is converted to a longer or shorter wavelength. In this way, these new crystals can simultaneously serve as self-frequency doubling crystals and laser materials within the laser resonator.

  19. Fullerene-doped porous glasses

    NASA Astrophysics Data System (ADS)

    Joshi, M. P.; Kukreja, L. M.; Rustagi, K. C.

    We report the doping of C60 in porous glass by diffusion in solution phase at room temperature. The presence of C60 in the doped porous glass was confirmed spectroscopically. We also report the changes in optical absorption spectrum and intensity-dependent transmission of 30 ns laser pulses at 527 nm in these materials.

  20. Mixed alkali effect on the spectroscopic properties of alkali-alkaline earth oxide borate glasses

    NASA Astrophysics Data System (ADS)

    Srinivas, G.; Ramesh, B.; Shareefuddin, Md.; Chary, M. N.; Sayanna, R.

    2016-05-01

    The mixed alkali and alkaline earth oxide borate glass with the composition xK2O - (25-x) Li2O-12.5BaO-12.5MgO-50B2O3 (x = 0, 5, 10, 15, 20 and 25mol %) and doped with 1mol% CuO were prepared by the melt quenching technique. From the optical absorption spectra the optical band gap, electronic polarizability(α02-), interaction parameter (A), theoretical and experimental optical basicity (Λ) values were evaluated. From the Electron Paramagnetic Resonance (EPR) spectral data the number of spins (N) and susceptibility (χ) were evaluated. The values of (α02-), and (Λ) increases with increasing of K2O content and electronic polarizability and interaction parameter show opposite behaviuor which may be due to the creation of non-bridging oxygens and expansion of borate network. The reciprocal of susceptibility (1/χ) and spin concentration (N) as a function of K2O content, varied nonlinearly which may be due to creation of non-bridging oxygens in the present glass system. This may be attributed to mixed alkali effect (MAE).

  1. Transition and post-transition metal ions in borate glasses: Borate ligand speciation, cluster formation, and their effect on glass transition and mechanical properties

    NASA Astrophysics Data System (ADS)

    Möncke, D.; Kamitsos, E. I.; Palles, D.; Limbach, R.; Winterstein-Beckmann, A.; Honma, T.; Yao, Z.; Rouxel, T.; Wondraczek, L.

    2016-09-01

    A series of transition and post-transition metal ion (Mn, Cu, Zn, Pb, Bi) binary borate glasses was studied with special consideration of the cations impact on the borate structure, the cations cross-linking capacity, and more generally, structure-property correlations. Infrared (IR) and Raman spectroscopies were used for the structural characterization. These complementary techniques are sensitive to the short-range order as in the differentiation of tetrahedral and trigonal borate units or regarding the number of non-bridging oxygen ions per unit. Moreover, vibrational spectroscopy is also sensitive to the intermediate-range order and to the presence of superstructural units, such as rings and chains, or the combination of rings. In order to clarify band assignments for the various borate entities, examples are given from pure vitreous B2O3 to meta-, pyro-, ortho-, and even overmodified borate glass compositions. For binary metaborate glasses, the impact of the modifier cation on the borate speciation is shown. High field strength cations such as Zn2+ enhance the disproportionation of metaborate to polyborate and pyroborate units. Pb2+ and Bi3+ induce cluster formation, resulting in PbOn- and BiOn-pseudophases. Both lead and bismuth borate glasses show also a tendency to stabilize very large superstructural units in the form of diborate polyanions. Far-IR spectra reflect on the bonding states of modifier cations in glasses. The frequency of the measured cation-site vibration band was used to obtain the average force constant for the metal-oxygen bonding, FM-O. A linear correlation between glass transition temperature (Tg) and FM-O was shown for the metaborate glass series. The mechanical properties of the glasses also correlate with the force constant FM-O, though for cations of similar force constant the fraction of tetrahedral borate units (N4) strongly affects the thermal and mechanical properties. For paramagnetic Cu- and Mn-borate glasses, N4 was determined

  2. Composition-structure-properties relationship of strontium borate glasses for medical applications.

    PubMed

    Hasan, Muhammad S; Werner-Zwanziger, Ulrike; Boyd, Daniel

    2015-07-01

    We have synthesized TiO2 doped strontium borate glasses, 70B2O3-(30-x)SrO-xTiO2 and 70B2 O3 -20SrO(10-x)Na2 O-xTiO2 . The composition dependence of glass structure, density, thermal properties, durability, and cytotoxicity of degradation products was studied. Digesting the glass in mineral acid and detecting the concentrations of various ions using an ICP provided the actual compositions that were 5-8% deviated from the theoretical values. The structure was investigated by means of (11)B magic angle spinning (MAS) NMR spectroscopy. DSC analyses provided the thermal properties and the degradation rates were measured by measuring the weight loss of glass disc-samples in phosphate buffered saline at 37°C in vitro. Finally, the MTT assay was used to analyze the cytotoxicity of the degradation products. The structural analysis revealed that replacing TiO2 for SrO or Na2 O increased the BO3/BO4 ratio suggesting the network-forming role of TiO2 . Thermal properties, density, and degradation rates also followed the structural changes. Varying SrO content predominantly controlled the degradation rates, which in turn controlled the ion release kinetics. A reasonable control (2-25% mass loss in 21 days) over mass loss was achieved in current study. Even though, very high concentrations (up to 5500 ppm B, and 1200 ppm Sr) of ions were released from the ternary glass compositions that saturated the degradation media in 7 days, the degradation products from ternary glass system was found noncytotoxic. However, quaternary glasses demonstrated negative affect on cell viability due to very high (7000 ppm) Na ion concentration. All the glasses investigated in current study are deemed fast degrading with further control over degradation rates, release kinetics desirable.

  3. Antiquenching effect of modifying cations on samarium clustering: Physical, structural and luminescent behavior of heavy metal borate glass systems

    NASA Astrophysics Data System (ADS)

    Kaur, Simranpreet; Kaur, Parvinder; Pal Singh, Gurinder; Kumar, Sunil; Singh, D. P.

    2015-09-01

    In this paper an attempt has been made to correlate the structural modifications and luminescence efficiencies by changing the environment of the glass network by modifying oxides. Sm3+ doped lead borate (SPB) and lead cadmium alumino borate (SCPB) glasses have been fabricated by melt quench technique at high temperature. The glass samples are characterized by XRD, FTIR, optical absorptions, fluorescence and density measurements. The effect of Sm3+ ion and glass host interaction on the emission spectra has been discussed in the view of the ionicity and covalency of hosts. The ratio of the intensities of electric to magnetic dipole emissions are calculated by varying both the concentration of the Sm3+ ion and the composition of the glass matrix. The XRD profile of all the glasses confirms their amorphous nature and FTIR spectrum shows the presence of BO3 and BO4 groups. These glasses have shown strong absorption bands in the visible (VIS and NIR) region and emit strong orange red wavelengths when excited by ultraviolet light. The concentration quenching has been noticed and ascribed to energy transfer through cross-relaxation between Sm3+ ions. Shifting of UV absorption edge towards longer wavelength with addition of Sm2O3 concentration has been observed. Incorporation of Al2O3 and CdO in 2nd glass system is responsible for strong effect on luminescence of the present glass system. Based on these results, an attempt has been made to throw some light on the relationship between the structural modifications and luminescence efficiencies in two different glass hosts as a laser active medium in the visible region. Moreover the optical basicity values were theoretically determined along with covalent behavior of two glass systems.

  4. Effects of copper on the preparation and characterization of Na-Ca-P borate glasses.

    PubMed

    Shailajha, S; Geetha, K; Vasantharani, P; Sheik Abdul Kadhar, S P

    2015-03-01

    Glasses in the system Na2O-CaO-B2O3-P2O5: CuO have been prepared by melt quenching at 1200°C and rapidly cooling at room temperature. The structural, optical and thermal properties have been investigated using X-ray diffraction (XRD), ultraviolet-visible (UV-VIS) spectroscopy, thermogravimetric-differential thermal analysis (TG-DTA), Fourier transform infrared (FTIR) spectroscopy, high resolution scanning electron microscopy (HRSEM) with energy dispersive X-ray (EDX) spectroscopy and high resolution transmission electron microscope (HRTEM) with energy dispersive X-ray (EDAX). The amorphous and crystalline nature of these samples was verified by XRD. Glass transition, crystallization and thermal stability were determined by TG-DTA investigations. Direct optical energy band gaps before and after doping with different percents of copper oxide were evaluated from 4.81eV to 2.99eV indicated the role of copper in the glassy matrix by UV spectra. FTIR spectrum reveals characteristic absorption bands due to various groups of triangular and tetrahedral borate network. Due to the amorphous nature, the particles like agglomerates on the glass surface were investigated by the HRSEM analysis. The crystalline nature of the samples in XRD is confirmed by SAED pattern using HRTEM. PMID:25605593

  5. EPR and optical absorption studies of Cu{sup 2+} ions in alkaline earth alumino borate glasses

    SciTech Connect

    Ramesh Kumar, V.; Rao, J.L. . E-mail: jlrao46@yahoo.co.in; Gopal, N.O.

    2005-08-11

    Electron paramagnetic resonance (EPR) and optical absorption spectra of Cu{sup 2+} ions in alkaline earth alumino borate glasses doped with different concentrations of CuO have been studied. The EPR spectra of all the glasses exhibit the resonance signals, characteristic of Cu{sup 2+} ions present in axially elongated octahedral sites. The number of spins participating in the resonance has been calculated as a function of temperature for calcium alumino borate (CaAB) glass doped with 0.1 mol% of CuO. From the EPR data, the paramagnetic susceptibility ({chi}) was calculated at different temperatures (T) and from the 1/{chi}-T graph, the Curie temperature of the glass has been evaluated. The optical absorption spectra of all the glasses show a single broad band, which has been assigned to the {sup 2}B{sub 1g} {yields} {sup 2}B{sub 2g} transition of the Cu{sup 2+} ions. The variation in the intensity of optical absorption with the ionic radius of the alkaline earth ion has been explained based on the Coulombic forces. By correlating the EPR and optical absorption spectral data, the nature of the in-plane {sigma} bonding between Cu{sup 2+} ion and the ligands is estimated. From the fundamental ultraviolet absorption edges of the glasses, the optical energy gap (E {sub opt}) and the Urbach energy ({delta}E) are evaluated. The variation in E {sub opt} and {delta}E is explained based on the number of defect centers in the glass.

  6. Effect of bioactive borate glass microstructure on bone regeneration, angiogenesis, and hydroxyapatite conversion in a rat calvarial defect model.

    PubMed

    Bi, Lianxiang; Rahaman, Mohamed N; Day, Delbert E; Brown, Zackary; Samujh, Christopher; Liu, Xin; Mohammadkhah, Ali; Dusevich, Vladimir; Eick, J David; Bonewald, Lynda F

    2013-08-01

    Borate bioactive glasses are biocompatible and enhance new bone formation, but the effect of their microstructure on bone regeneration has received little attention. In this study scaffolds of borate bioactive glass (1393B3) with three different microstructures (trabecular, fibrous, and oriented) were compared for their capacity to regenerate bone in a rat calvarial defect model. 12weeks post-implantation the amount of new bone, mineralization, and blood vessel area in the scaffolds were evaluated using histomorphometric analysis and scanning electron microscopy. The amount of new bone formed was 33%, 23%, and 15%, respectively, of the total defect area for the trabecular, oriented, and fibrous microstructures. In comparison, the percent new bone formed in implants composed of silicate 45S5 bioactive glass particles (250-300μm) was 19%. Doping the borate glass with copper (0.4 wt.% CuO) had little effect on bone regeneration in the trabecular and oriented scaffolds, but significantly enhanced bone regeneration in the fibrous scaffolds (from 15 to 33%). The scaffolds were completely converted to hydroxyapatite within the 12week implantation. The amount of hydroxyapatite formed, 22%, 35%, and 48%, respectively, for the trabecular, oriented, and fibrous scaffolds, increased with increasing volume fraction of glass in the as-fabricated scaffold. Blood vessels infiltrated into all the scaffolds, but the trabecular scaffolds had a higher average blood vessel area compared with the oriented and fibrous scaffolds. While all three scaffold microstructures were effective in supporting bone regeneration, the trabecular scaffolds supported more bone formation and may be more promising in bone repair.

  7. Structural and optical characteristics of Eu3+ ions in sodium-lead-zinc-lithium-borate glass system

    NASA Astrophysics Data System (ADS)

    Rajagukguk, J.; Kaewkhao, J.; Djamal, M.; Hidayat, R.; Suprijadi; Ruangtaweep, Y.

    2016-10-01

    Structural and optical properties of Eu3+-doped sodium-lead-zinc-lithium-borate glasses (65-x)B2O3sbnd 15Na2Osbnd 10PbOsbnd 5ZnOsbnd 5Li2Osbnd xEu2O3 (where x = 0, 0.05, 0.1, 0.5, 1.0, 2.0 and 4.0) have been measured and analyzed by varying the Eu3+ ion concentrations. The physical parameters such as polaron radius, field strength and inter nuclear distance have been determined from measurements of densities and refractive indices. The structural properties of the prepared borate glasses were analyzed based on X-ray diffraction (XRD) and FTIR instruments. The diffraction spectra show no characteristic peaks in these glasses, which indicates the amorphous nature of the glasses. The infrared spectrum of the Eu3+-doped sodium-lead-zinc-lithium-borate glass systems show three disparate regions for active absorption band around 830-860 cm-1, 1020-1040 cm-1 and 1170-1180 cm-1. The electronic transitions in the UV-vis and NIR regions are assigned to the 7F0 → 5D4, 7F0 → 5G2, 7F0 → 5L6, 7F0 → 5D3, 7F0 → 5D2, 7F0 → 5D1, 7F0 → 5D07F1 → 5D07F0 → 7F6 and 7F1 → 7F6 levels centered at 362 nm, 380 nm, 395 nm, 414 nm, 465 nm, 533 nm, 583 nm, 590 nm 2092 nm and 2202 nm respectively. Five transition bands of luminescence spectra have been observed by using an excited wavelength of 395 nm. The luminescence intensity ratio (R) of 5D0 → 7F2 (electric dipole) transition to 5D0 → 7F1 (magnetic dipole) transition has been determined to obtain the strength of the covalent/ionic bond between the Eu3+ ions and the surrounding ligands. Radiative life time and emission color of the glasses were estimated and compared with other literature data by varying Eu3+ concentrations. The experimental lifetime of the 5D0 level was found to increase with increasing Eu3+ ion content, suggesting higher non-radiative energy transfer among Eu3+ ions in the glasses.

  8. Investigation of luminescence and spectroscopic properties of Nd3+ions in cadmium alkali borate glasses

    NASA Astrophysics Data System (ADS)

    Mohan, Shaweta; Thind, Kulwant Singh

    2016-07-01

    Neodymium doped cadmium alkali borate glasses having composition 20CdOsbnd 20R2Osbnd 59.5H3BO3sbnd 0.5Nd2O3; (R = Li, Na and K) were prepared by conventional melt-quenching technique. The amorphous nature of the glasses was confirmed by X-ray diffraction studies. The physical properties such as density, refractive index, molar volume, rare earth ion concentration etc. were determined. Optical absorption and fluorescence spectra were recorded. The Judd-Ofelt theory was applied on the optical absorption spectra of the glasses to evaluate the three phenomenological intensity parameters Ω2, Ω4 and Ω6. These parameters were in turn used to predict the radiative properties such as the radiative transition probability (A), radiative lifetime (τR) and branching ratio (βR) for the fluorescent levels of Nd3+ ion in the present glass series. The lasing efficiency of the prepared glasses has been characterized by the spectroscopic quality factor (Ω4/Ω6), the value of which is in the range of 0.2-1.5, typical for Nd3+ in different laser hosts. The variation of Ω2 with the change in alkali oxide has been attributed to the changes in the asymmetry of the ligand field at the rare earth ion site. The shift of the hypersensitive bands, study of the oscillator strengths and the variation of the spectral profile of the transition 4I9/2 → 4F7/2 + 4S3/2 indicate a maximum covalency of Ndsbnd O bond for glass with potassium ions. From the fluorescence spectra, peak wavelength (λp), effective line widths (Δλeff) and stimulated emission cross-section (σp) have been obtained for the three transitions 4F3/2 → 4I9/2,4F3/2 → 4I11/2 and4F3/2 → 4I13/2 of Nd3+ ion. The relatively high values of σp obtained for Nd3+ in present glass system suggest that these materials can be considered as suitable candidates for laser applications. The glass with potassium ions shows the highest value of the stimulated emission cross-section.

  9. Ultrasonic and Thermal Properties of Borate and Phosphate Glasses Containing Bismuth and Lead

    SciTech Connect

    Aziz, Sidek Hj. Abd.; Ahmad, Hamezan; Wahab, Zaidan A.; Sulaiman, Zainal Abidin; Talib, Zainal Abidin; Shaari, A. Halim; Senin, H. B.

    2007-05-09

    Systematic series of (B2O3,P2O5)-Bi2O3-PbO glasses have been successfully prepared by using the rapid quenching technique in which each oxide content changes for every series on the basis of its weight percentage. Their amorphous natures were confirmed earlier by the x-ray diffraction technique. The experimental results show that the density of both glasses, determined by using the Archimedes principle, increases with the glass modifier content. This is due to the replacement of Bi2O3 and PbO in the borate and phosphate glassy networks. The molar volume for borate glass increases with the addition of bismuth and lead oxides, but a reverse trend occurs for the phosphate glass. The longitudinal and shear ultrasound velocities, determined by the MBS 8000 system, of both lead bismuth borate and phosphate glasses show a decreasing trend as more PbO and Bi2O3 are added to the glass system. The increase in PbO/Bi2O3 content was probably related to the progressive increase in the concentration of non-bridging oxygen (NBOs). Thermal studies of the glass, using the Labsys DTA-Setaram machine, show that the value of the glass transition temperature (Tg) is closely related to the chemical bond in the system. In lead bismuth borate glasses, the addition of more Pb2+ and Bi3+ results in a more dominant ionic bond character in the system and hence decreases Tg of the sample. However, in lead bismuth phosphate glasses, the addition of Pb2+ and Bi3+ not only failed to weaken the covalent character in P-O-P bonds, but strengthened it further, leading to an increment in the values of Tg.

  10. Ultrasonic and Thermal Properties of Borate and Phosphate Glasses Containing Bismuth and Lead

    NASA Astrophysics Data System (ADS)

    Aziz, Sidek Hj. Abd.; Ahmad, Hamezan; Wahab, Zaidan A.; Sulaiman, Zainal Abidin; Talib, Zainal Abidin; Shaari, A. Halim; Senin, H. B.

    2007-05-01

    Systematic series of (B2O3,P2O5)-Bi2O3-PbO glasses have been successfully prepared by using the rapid quenching technique in which each oxide content changes for every series on the basis of its weight percentage. Their amorphous natures were confirmed earlier by the x-ray diffraction technique. The experimental results show that the density of both glasses, determined by using the Archimedes principle, increases with the glass modifier content. This is due to the replacement of Bi2O3 and PbO in the borate and phosphate glassy networks. The molar volume for borate glass increases with the addition of bismuth and lead oxides, but a reverse trend occurs for the phosphate glass. The longitudinal and shear ultrasound velocities, determined by the MBS 8000 system, of both lead bismuth borate and phosphate glasses show a decreasing trend as more PbO and Bi2O3 are added to the glass system. The increase in PbO/Bi2O3 content was probably related to the progressive increase in the concentration of non-bridging oxygen (NBOs). Thermal studies of the glass, using the Labsys DTA-Setaram machine, show that the value of the glass transition temperature (Tg) is closely related to the chemical bond in the system. In lead bismuth borate glasses, the addition of more Pb2+ and Bi3+ results in a more dominant ionic bond character in the system and hence decreases Tg of the sample. However, in lead bismuth phosphate glasses, the addition of Pb2+ and Bi3+ not only failed to weaken the covalent character in P-O-P bonds, but strengthened it further, leading to an increment in the values of Tg.

  11. Optical and structural characterization of yttrium calcium borate glasses

    NASA Astrophysics Data System (ADS)

    Santos, Cristiane; Meneses, Domingos D. S.; Echegut, Patrick; Neuville, Daniel R.; Hernandes, Antonio C.; Ibanez, Alain

    2010-03-01

    Structural and optical properties of new stable glasses in the Y2O3 -- CaO -- B2O3 system, containing the same Y/Ca ratio as the YCa4O(BO3)3 (YCOB) crystal, were determined from Raman and reflectance infrared spectroscopy [1]. We have obtained the optical functions using a dielectric function model and their evolution with composition are associated with an increase in the number of non-bridging oxygen and to calcium/yttrium oxides content with the formation of pentaborate, metaborate, orthoborate and pyroborate groups. The orthoborate and pyroborate signatures increase with increasing the modifier cations. Refractive indexes values (from 1.597 to 1.627 at λ = 2 μm) are in good agreement with those of the YCOB crystal, an indication that these glasses are potential candidates for doping with rare-earth ions for optical applications. [4pt] [1] C. N. Santos, D.D.S. Meneses, P. Echegut, D. R. Neuville, A. C. Hernandes, A. Ibanez, Appl. Phys. Lett. 94, 151901(2009).

  12. Atom probe tomography of lithium-doped network glasses.

    PubMed

    Greiwe, Gerd-Hendrik; Balogh, Zoltan; Schmitz, Guido

    2014-06-01

    Li-doped silicate and borate glasses are electronically insulating, but provide considerable ionic conductivity. Under measurement conditions of laser-assisted atom probe tomography, mobile Li ions are redistributed in response to high electric fields. In consequence, the direct interpretation of measured composition profiles is prevented. It is demonstrated that composition profiles are nevertheless well understood by a complex model taking into account the electronic structure of dielectric materials, ionic mobility and field screening. Quantitative data on band bending and field penetration during measurement are derived which are important in understanding laser-assisted atom probe tomography of dielectric materials.

  13. Study of structural, electrical, and dielectric properties of phosphate-borate glasses and glass-ceramics

    NASA Astrophysics Data System (ADS)

    Melo, B. M. G.; Graça, M. P. F.; Prezas, P. R.; Valente, M. A.; Almeida, A. F.; Freire, F. N. A.; Bih, L.

    2016-08-01

    In this work, phosphate-borate based glasses with molar composition 20.7P2O5-17.2Nb2O5-13.8WO3-34.5A2O-13.8B2O3, where A = Li, Na, and K, were prepared by the melt quenching technique. The as-prepared glasses were heat-treated in air at 800 °C for 4 h, which led to the formation of glass-ceramics. These high chemical and thermal stability glasses are good candidates for several applications such as fast ionic conductors, semiconductors, photonic materials, electrolytes, hermetic seals, rare-earth ion host solid lasers, and biomedical materials. The present work endorses the analysis of the electrical conductivity of the as-grown samples, and also the electrical, dielectric, and structural changes established by the heat-treatment process. The structure of the samples was analyzed using X-Ray powder Diffraction (XRD), Raman spectroscopy, and density measurements. Both XRD and Raman analysis confirmed crystals formation through the heat-treatment process. The electrical ac and dc conductivities, σac and σdc, respectively, and impedance spectroscopy measurements as function of the temperature, varying from 200 to 380 K, were investigated for the as-grown and heat-treated samples. The impedance spectroscopy was measured in the frequency range of 100 Hz-1 MHz.

  14. Evaluation of borate bioactive glass scaffolds with different pore sizes in a rat subcutaneous implantation model.

    PubMed

    Deliormanli, Aylin M; Liu, Xin; Rahaman, Mohamed N

    2014-01-01

    Borate bioactive glass has been shown to convert faster and more completely to hydroxyapatite and enhance new bone formation in vivo when compared to silicate bioactive glass (such as 45S5 and 13-93 bioactive glass). In this work, the effects of the borate glass microstructure on its conversion to hydroxyapatite (HA) in vitro and its ability to support tissue ingrowth in a rat subcutaneous implantation model were investigated. Bioactive borate glass scaffolds, designated 13-93B3, with a grid-like microstructure and pore widths of 300, 600, and 900 µm were prepared by a robocasting technique. The scaffolds were implanted subcutaneously for 4 weeks in Sprague Dawley rats. Silicate 13-93 glass scaffolds with the same microstructure were used as the control. The conversion of the scaffolds to HA was studied as a function of immersion time in a simulated body fluid. Histology and scanning electron microscopy were used to evaluate conversion of the bioactive glass implants to hydroxyapatite, as well as tissue ingrowth and blood vessel formation in the implants. The pore size of the scaffolds was found to have little effect on tissue infiltration and angiogenesis after the 4-week implantation.

  15. The effect of composition on the viscosity, crystallization and dissolution of simple borate glasses and compositional design of borate based bioactive glasses

    NASA Astrophysics Data System (ADS)

    Goetschius, Kathryn Lynn

    Borate glasses have recently been developed for a variety of medical applications, but much less is known about their structures and properties than more common silicate glasses. Melt properties and crystallization tendency for compositions in the Na2O-CaO-B2O3 system were characterized using differential thermal analysis and viscosity measurements. Characteristic viscosity (isokom) temperatures varied with the ratio between the modifier content (Na2O+CaO) and B2O3, particularly at lower temperatures, consistent with the changes in the relative concentrations of tetrahedral borons in the glass structure. Similar glasses were used to study dissolution processes in water. These alkali-alkaline earth glasses dissolve congruently and follow linear dissolution kinetics. The dissolution rates were dependent on the glass structure, with slower rates associated with greater fractions of four-coordinated boron. For glasses with a fixed alkaline earth identity, the dissolution rates increased in the order Liglasses with a constant alkali identity, the dissolution rates increased in the order Caborate-based bioactive compositions for specific applications. Melt viscosity, thermal expansion coefficient, liquidus temperature and crystallization tendency were determined, as were dissolution rates in simulated body fluid (SBF).

  16. The effect of MgO on the optical properties of lithium sodium borate doped with Cu+ ions

    NASA Astrophysics Data System (ADS)

    Alajerami, Yasser Saleh Mustafa; Hashim, Suhairul; Hassan, Wan Muhamad Saridan Wan; Ramli, Ahmad Termizi; Saleh, Muneer Aziz

    2013-04-01

    The current work presented the photoluminescence (PL) properties of a new glass system, which are reported for the first time. Based on the attractive properties of borate glass, a mixture of boric acid (70-x mol %) modified with lithium (20 mol %) and sodium carbonate (10 mol %) was prepared. The current study illustrated the effect of dopant and co-dopant techniques on the lithium sodium borate (LNB). Firstly, 0.1 mol % of copper ions doped with LNB was excited at 610 nm. The emission spectrum showed two prominent peaks in the violet region (403 and 440 nm). Then, we remarked the effect of adding different concentration of MgO on the optical properties of LNB. The results showed the great effect of magnesium oxide on the PL intensities (enhanced more than two times). Moreover, an obvious shifting has been defined toward the blue region (440 → 475 nm). The up-conversion optical properties were observed in all emission spectra. This enhancement is contributed to the energy transfer from MgO ions to monovalent Cu+ ion. It is well known that magnesium oxide alone generates weak emission intensity, but during this increment the MgO act as an activator (co-doped) for Cu+ ions. Finally, energy band gap, density, ion concentration, molar volume, Polaron radius and inter-nuclear distance all were measured for the current samples. The current samples were subjected to XRD for amorphous confirmation and IR for glass characterization before and after dopants addition. Finally, some of significant physical and optical parameters were also calculated.

  17. Vibrational study of lithium sulfate based fast ionic conducting borate glasses

    SciTech Connect

    Kamitsos, E.I.; Karakassides, M.A.; Chryssikos, G.D.

    1986-09-11

    The influence of the sulfate anion on the structure of the xLi/sub 2/O x yLi/sub 2/SO/sub 4/ x B/sub 2/O/sub 3/ fast ionic conducting glasses has been studied by Raman and Fourier-transform infrared spectroscopies, for compositions probing the whole glass-forming region (x = 0.20, 0.56; y = 0-0.50). Difference spectra are presented to elucidate the SO/sub 4//sup 2 -/-induced structural changes. Thus, for the x = 0.20 series, combined Raman and infrared results showed that Li/sub 2/SO/sub 4/ additions induce the formation of BO/sub 4/ tetrahedra. However, for high lithium oxide content ternary glasses (x = 0.56), while Raman spectra did not show obvious changes of the glass structure upon increasing y, infrared spectra clearly indicated that the numbers of BO/sub 4/ tetrahedra and nonbridging oxygen-containing borate groups both increase. It was concluded that the presence of SO/sub 4//sup 2 -/ anions, in the glass melt, favors the formation of borate groups, which are more polar than those of the corresponding binary glasses.

  18. Compositional dependence of optical band gap and refractive index in lead and bismuth borate glasses

    SciTech Connect

    Mallur, Saisudha B.; Czarnecki, Tyler; Adhikari, Ashish; Babu, Panakkattu K.

    2015-08-15

    Highlights: • Refractive indices increase with increasing PbO/Bi{sub 2}O{sub 3} content. • Optical band gap arises due to direct forbidden transition. • Optical band gaps decrease with increasing PbO/Bi{sub 2}O{sub 3} content. • New empirical relation between the optical band gap and the refractive index. - Abstract: We prepared a series of lead and bismuth borate glasses by varying PbO/Bi{sub 2}O{sub 3} content and studied refractive index and optical band gap as a function of glass composition. Refractive indices were measured very accurately using a Brewster’s angle set up while the optical band gaps were determined by analyzing the optical absorption edge using the Mott–Davis model. Using the Lorentz–Lorentz method and the effective medium theory, we calculated the refractive indices and then compared them with the measured values. Bismuth borate glasses show better agreement between the calculated values of the refractive index and experimental values. We used a differential method based on Mott–Davis model to obtain the type of transition and optical band gap (E{sub opt}) which in turn was compared with the value of E{sub opt} obtained using the extinction coefficient. Our analysis shows that in both lead and bismuth borate glasses, the optical band gap arises due to direct forbidden transition. With increasing PbO/Bi{sub 2}O{sub 3} content, the absorption edge shifts toward longer wavelengths and the optical band gap decreases. This behavior can be explained in terms of changes to the Pb−O/Bi−O chemical bonds with glass composition. We obtained a new empirical relation between the optical band gap and the refractive index which can be used to accurately determine the electronic oxide polarizability in lead and bismuth oxide glasses.

  19. Optical limiting in semiconductor-doped glasses

    NASA Astrophysics Data System (ADS)

    Bindra, K. S.; Oak, S. M.; Rustagi, K. C.

    1996-02-01

    We report optical limiting at 527 nm in two Schott semiconductor-doped glasses OG530 and OG515. These two glasses show quite contrasting nonlinear optical behaviour. The glass OG515 shows strong clamping while OG530 shows no clamping in optical limiting inspite of having much larger nonlinear refractive index. Similarly OG530 exhibits saturation of absorption while OG515 does not.

  20. Impact of network topology on cationic diffusion and hardness of borate glass surfaces

    NASA Astrophysics Data System (ADS)

    Smedskjaer, Morten M.; Mauro, John C.; Sen, Sabyasachi; Deubener, Joachim; Yue, Yuanzheng

    2010-10-01

    The connection between bulk glass properties and network topology is now well established. However, there has been little attention paid to the impact of network topology on the surface properties of glass. In this work, we report the impact of the network topology on both the transport properties (such as cationic inward diffusion) and the mechanical properties (such as hardness) of borate glasses with modified surfaces. We choose soda lime borate systems as the object of this study because of their interesting topological features, e.g., boron anomaly. An inward diffusion mechanism is employed to modify the glass surface compositions and hence the surface topology. We show that accurate quantitative predictions of the hardness of the modified surfaces can be made using topological constraint theory with temperature-dependent constraints. Experimental results reveal that Ca2+ diffusion is most intense in glasses with lowest BO4 fraction, whereas Na+ diffusion is only significant when nonbridging oxygens start to form. These phenomena are interpreted in terms of the atomic packing and the local electrostatic environments of the cations.

  1. Cation-network interactions in binary alkali metal borate glasses. A far-infrared study

    SciTech Connect

    Kamitsos, E.I.; Karakassides, M.A.; Chryssikos, G.D.

    1987-10-22

    The far-infrared spectra of compositions probing the glass-forming regions of all five binary alkali metal borate systems chi M/sub 2/O x (1 - chi)B/sub 2/O/sub 3/ (0 < chi less than or equal to 0.40, M = Na; and 0 < chi less than or equal to 0.35, M = K, Rb, Cs) have been measured and analyzed to systematically study the alkali metal cation-network interactions and their compositional dependence. Band deconvolution of the measured spectra showed the presence of two distinct distributions of alkali metal cation sites in Li, Na, and K glasses. Similar results have been obtained for rubidium and cesium borate glasses of compositions chi > 0.25. One distribution of cation sites has been observed for the lower alkali metal content Rb and Cs glasses. The fractions of cations in the two different network sites have also been evaluated. The squares of the frequencies of the cation-motion bands were found to vary linearly with composition, and exhibit kinks at chi similarly ordered 20, for all but the Cs glasses. This behavior was explained on the basis of the network structural changes known to occur at this composition.

  2. Continuous-wave laser action of Yb3+-doped lanthanum scandium borate

    NASA Astrophysics Data System (ADS)

    Romero, J. J.; Johannsen, J.; Mond, M.; Petermann, K.; Huber, G.; Heumann, E.

    2005-02-01

    Lanthanum scandium borate (LSB) has been proved to be an interesting laser matrix when doped with Nd3+ and Er3+ ions. In this paper, we demonstrate that it is also a very efficient laser material when doped with Yb3+ ions. The main spectroscopic characteristics of the system are presented, showing very broad absorption and emission bands, comparable to those found in Yb-doped GdCOB and YCOB crystals. From spectroscopic measurements the relevant laser parameters have been obtained, and a tunability of about 50 nm could be deduced. Room-temperature, continuous-wave laser action of Yb-doped LSB is demonstrated at a wavelength of 1045 nm with a slope efficiency as high as 64%.

  3. Structural, dielectric, and optical properties of yttrium calcium borate glasses

    NASA Astrophysics Data System (ADS)

    Santos, Cristiane N.; De Sousa Meneses, Domingos; Echegut, Patrick; Neuville, Daniel R.; Hernandes, Antonio C.; Ibanez, Alain

    2009-04-01

    Structural and optical properties of stable glasses in the Y2O3-CaO-B2O3 system, containing the same Y/Ca ratio as the YCa4O(BO3)3 (YCOB) crystal, were determined from Raman and reflectance infrared spectroscopy. Changes in optical functions with composition are associated with an increase in the number of non-bridging oxygen and to calcium/yttrium oxides content. Refractive indexes values (from 1.597 to 1.627 at λ =2 μm) are in good agreement with those of the YCOB crystal, an indication that these glasses are potential candidates for optical applications due to their ease of shaping as large bulk samples or fibers.

  4. Role of SrO on the bioactivity behavior of some ternary borate glasses and their glass ceramic derivatives.

    PubMed

    Abdelghany, A M; Ouis, M A; Azooz, M A; ElBatal, H A; El-Bassyouni, G T

    2016-01-01

    Borate glasses containing SrO substituting both CaO and NaO were prepared and characterized for their bioactivity or bone bonding ability. Glass ceramic derivatives were prepared by thermal heat treatment process. FTIR, XRD and SEM measurements for the prepared glass and glass-ceramics before and after immersion in sodium phosphate solution for one and two weeks were carried out. The appearance of two IR peaks within the range 550-680cm(-1) after immersion in phosphate solution indicates the formation of hydroxyapatite or equivalent Sr phosphate layer. X-ray diffraction data agree with the FTIR spectral analysis. The solubility test was carried out for both glasses and glass ceramics derivatives in the same phosphate solution. The introduction of SrO increases the solubility for both glasses and glass ceramics and this is assumed to be due to the formation of Sr phosphate which is more soluble than calcium phosphate (hydroxyapatite). SEM images reveal varying changes in the surfaces of glass ceramics after immersion according to the SrO content.

  5. Role of SrO on the bioactivity behavior of some ternary borate glasses and their glass ceramic derivatives.

    PubMed

    Abdelghany, A M; Ouis, M A; Azooz, M A; ElBatal, H A; El-Bassyouni, G T

    2016-01-01

    Borate glasses containing SrO substituting both CaO and NaO were prepared and characterized for their bioactivity or bone bonding ability. Glass ceramic derivatives were prepared by thermal heat treatment process. FTIR, XRD and SEM measurements for the prepared glass and glass-ceramics before and after immersion in sodium phosphate solution for one and two weeks were carried out. The appearance of two IR peaks within the range 550-680cm(-1) after immersion in phosphate solution indicates the formation of hydroxyapatite or equivalent Sr phosphate layer. X-ray diffraction data agree with the FTIR spectral analysis. The solubility test was carried out for both glasses and glass ceramics derivatives in the same phosphate solution. The introduction of SrO increases the solubility for both glasses and glass ceramics and this is assumed to be due to the formation of Sr phosphate which is more soluble than calcium phosphate (hydroxyapatite). SEM images reveal varying changes in the surfaces of glass ceramics after immersion according to the SrO content. PMID:26204506

  6. Role of SrO on the bioactivity behavior of some ternary borate glasses and their glass ceramic derivatives

    NASA Astrophysics Data System (ADS)

    Abdelghany, A. M.; Ouis, M. A.; Azooz, M. A.; ElBatal, H. A.; El-Bassyouni, G. T.

    2016-01-01

    Borate glasses containing SrO substituting both CaO and NaO were prepared and characterized for their bioactivity or bone bonding ability. Glass ceramic derivatives were prepared by thermal heat treatment process. FTIR, XRD and SEM measurements for the prepared glass and glass-ceramics before and after immersion in sodium phosphate solution for one and two weeks were carried out. The appearance of two IR peaks within the range 550-680 cm-1 after immersion in phosphate solution indicates the formation of hydroxyapatite or equivalent Sr phosphate layer. X-ray diffraction data agree with the FTIR spectral analysis. The solubility test was carried out for both glasses and glass ceramics derivatives in the same phosphate solution. The introduction of SrO increases the solubility for both glasses and glass ceramics and this is assumed to be due to the formation of Sr phosphate which is more soluble than calcium phosphate (hydroxyapatite). SEM images reveal varying changes in the surfaces of glass ceramics after immersion according to the SrO content.

  7. Synthesis and characterization of cerium- and gallium-containing borate bioactive glass scaffolds for bone tissue engineering.

    PubMed

    Deliormanlı, Aylin M

    2015-02-01

    Bioactive glasses are widely used in biomedical applications due to their ability to bond to bone and even to soft tissues. In this study, borate based (13-93B3) bioactive glass powders containing up to 5 wt% Ce2O3 and Ga2O3 were prepared by the melt quench technique. Cerium (Ce+3) and gallium (Ga+3) were chosen because of their low toxicity associated with bacteriostatic properties. Bioactive glass scaffolds were fabricated using the polymer foam replication method. In vitro degradation and bioactivity of the scaffolds were evaluated in SBF under static conditions. Results revealed that the cerium- and gallium-containing borate glasses have much lower degradation rates compared to the bare borate glass 13-93B3. In spite of the increased chemical durability, substituted glasses exhibited a good in vitro bioactive response except when the Ce2O3 content was 5 wt%. Taking into account the high in vitro hydroxyapatite forming ability, borate glass scaffolds containing Ce+3 and Ga+3 therapeutic ions are promising candidates for bone tissue engineering applications.

  8. Synthesis and characterization of cerium- and gallium-containing borate bioactive glass scaffolds for bone tissue engineering.

    PubMed

    Deliormanlı, Aylin M

    2015-02-01

    Bioactive glasses are widely used in biomedical applications due to their ability to bond to bone and even to soft tissues. In this study, borate based (13-93B3) bioactive glass powders containing up to 5 wt% Ce2O3 and Ga2O3 were prepared by the melt quench technique. Cerium (Ce+3) and gallium (Ga+3) were chosen because of their low toxicity associated with bacteriostatic properties. Bioactive glass scaffolds were fabricated using the polymer foam replication method. In vitro degradation and bioactivity of the scaffolds were evaluated in SBF under static conditions. Results revealed that the cerium- and gallium-containing borate glasses have much lower degradation rates compared to the bare borate glass 13-93B3. In spite of the increased chemical durability, substituted glasses exhibited a good in vitro bioactive response except when the Ce2O3 content was 5 wt%. Taking into account the high in vitro hydroxyapatite forming ability, borate glass scaffolds containing Ce+3 and Ga+3 therapeutic ions are promising candidates for bone tissue engineering applications. PMID:25631259

  9. Conductivity and modulus formulation in lithium modified bismuth zinc borate glasses

    NASA Astrophysics Data System (ADS)

    Dahiya, Sajjan; Punia, R.; Murugavel, S.; Maan, A. S.

    2016-05-01

    The conductivity and modulus formulation in lithium modified bismuth zinc borate glasses with compositions xLi2O-(50-x) Bi2O3-10ZnO-40B2O3 has been studied in the frequency range 0.1 Hz-1.5 × 105 Hz in the temperature range 573 K-693 K. The temperature and frequency dependent conductivity is found to obey Jonscher's universal power law for all the studied compositions, the dc conductivity (σdc), crossover frequency (ωH), and frequency exponent (s) have been estimated from the fitting of the experimental data of ac conductivity with Jonscher's universal power law. Enthalpy to dissociate the cation from its original site next to a charge compensating centre (Hf) and enthalpy of migration (Hm) have been estimated. It has been observed that number of charge carriers and ac conductivity in the lithium modified bismuth zinc borate glasses increases with increase in Li2O content. Further, the conduction mechanism in the glass sample with x = 0 may be due to overlapping large polaron tunneling, whereas, conduction mechanism in other studied glass samples more or less follows diffusion controlled relaxation model. The ac conductivity is scaled using σdc and ωH as the scaling parameter and is found that these are suitable scaling parameter for conductivity scaling. Non-Debye type relaxation is found prevalent in the studied glass system. Scaling of ac conductivity as well as electric modulus confirms the presence of different type of conduction mechanism in the glass samples with x = 0 and 5 from other studied samples. The activation energy of relaxation (ER) and dc conductivity (Edc) are almost equal, suggesting that polarons/ions have to overcome same barrier while relaxing and conducting.

  10. Evaluation of injectable strontium-containing borate bioactive glass cement with enhanced osteogenic capacity in a critical-sized rabbit femoral condyle defect model.

    PubMed

    Zhang, Yadong; Cui, Xu; Zhao, Shichang; Wang, Hui; Rahaman, Mohamed N; Liu, Zhongtang; Huang, Wenhai; Zhang, Changqing

    2015-02-01

    The development of a new generation of injectable bone cements that are bioactive and have enhanced osteogenic capacity for rapid osseointegration is receiving considerable interest. In this study, a novel injectable cement (designated Sr-BBG) composed of strontium-doped borate bioactive glass particles and a chitosan-based bonding phase was prepared and evaluated in vitro and in vivo. The bioactive glass provided the benefits of bioactivity, conversion to hydroxyapatite, and the ability to stimulate osteogenesis, while the chitosan provided a cohesive biocompatible and biodegradable bonding phase. The Sr-BBG cement showed the ability to set in situ (initial setting time = 11.6 ± 1.2 min) and a compressive strength of 19 ± 1 MPa. The Sr-BBG cement enhanced the proliferation and osteogenic differentiation of human bone marrow-derived mesenchymal stem cells in vitro when compared to a similar cement (BBG) composed of chitosan-bonded borate bioactive glass particles without Sr. Microcomputed tomography and histology of critical-sized rabbit femoral condyle defects implanted with the cements showed the osteogenic capacity of the Sr-BBG cement. New bone was observed at different distances from the Sr-BBG implants within eight weeks. The bone-implant contact index was significantly higher for the Sr-BBG implant than it was for the BBG implant. Together, the results indicate that this Sr-BBG cement is a promising implant for healing irregularly shaped bone defects using minimally invasive surgery.

  11. Evaluation of injectable strontium-containing borate bioactive glass cement with enhanced osteogenic capacity in a critical-sized rabbit femoral condyle defect model.

    PubMed

    Zhang, Yadong; Cui, Xu; Zhao, Shichang; Wang, Hui; Rahaman, Mohamed N; Liu, Zhongtang; Huang, Wenhai; Zhang, Changqing

    2015-02-01

    The development of a new generation of injectable bone cements that are bioactive and have enhanced osteogenic capacity for rapid osseointegration is receiving considerable interest. In this study, a novel injectable cement (designated Sr-BBG) composed of strontium-doped borate bioactive glass particles and a chitosan-based bonding phase was prepared and evaluated in vitro and in vivo. The bioactive glass provided the benefits of bioactivity, conversion to hydroxyapatite, and the ability to stimulate osteogenesis, while the chitosan provided a cohesive biocompatible and biodegradable bonding phase. The Sr-BBG cement showed the ability to set in situ (initial setting time = 11.6 ± 1.2 min) and a compressive strength of 19 ± 1 MPa. The Sr-BBG cement enhanced the proliferation and osteogenic differentiation of human bone marrow-derived mesenchymal stem cells in vitro when compared to a similar cement (BBG) composed of chitosan-bonded borate bioactive glass particles without Sr. Microcomputed tomography and histology of critical-sized rabbit femoral condyle defects implanted with the cements showed the osteogenic capacity of the Sr-BBG cement. New bone was observed at different distances from the Sr-BBG implants within eight weeks. The bone-implant contact index was significantly higher for the Sr-BBG implant than it was for the BBG implant. Together, the results indicate that this Sr-BBG cement is a promising implant for healing irregularly shaped bone defects using minimally invasive surgery. PMID:25591177

  12. In vivo and in vitro studies of borate based glass micro-fibers for dermal repairing.

    PubMed

    Zhou, Jie; Wang, Hui; Zhao, Shichang; Zhou, Nai; Li, Le; Huang, Wenhai; Wang, Deping; Zhang, Changqing

    2016-03-01

    Full-thickness skin defects represent urgent clinical problem nowadays. Wound dressing materials are hotly needed to induce dermal reconstruction or to treat serious skin defects. In this study, the borate bioactive glass (BG) micro-fibers were fabricated and compared with the traditional material 45S5 Bioglass(®) (SiG) micro-fibers. The morphology, biodegradation and bioactivity of BG and SiG micro-fibers were investigated in vitro. The wound size reduction and angiogenic effects of BG and SiG micro-fibers were evaluated by the rat full-thickness skin defect model and Microfil technique in vivo. Results indicated that the BG micro-fibers showed thinner fiber diameter (1 μm) and better bioactivity than the SiG micro-fibers did. The ionic extracts of BG and SiG micro-fibers were not toxic to human umbilical vein endothelial cells (HUVECs). In vivo, the BG micro-fiber wound dressings obviously enhanced the formation of blood vessel, and resulted in a much faster wound size reduction than the SiG micro-fibers, or than the control groups, after 9 days application. The good skin defect reconstruction ability of BG micro-fibers contributed to the B element in the composition, which results in the better bioactivity and angiogenesis. As shown above, the novel bioactive borate glass micro-fibers are expected to provide a promising therapeutic alternative for dermal reconstruction or skin defect repair.

  13. Gentamicin-Loaded Borate Bioactive Glass Eradicates Osteomyelitis Due to Escherichia coli in a Rabbit Model

    PubMed Central

    Xie, Zongping; Cui, Xu; Zhao, Cunju; Huang, Wenhai; Wang, Jianqiang

    2013-01-01

    The treatment of osteomyelitis induced by Gram-negative bacilli is rarely reported in the literature. This study established a rabbit tibia model of osteomyelitis induced by the Gram-negative bacillus Escherichia coli. Using this model, pellets composed of a chitosan-bonded mixture of borate bioactive glass and gentamicin were evaluated in vitro and in vivo for the treatment of osteomyelitis induced by Escherichia coli. Our results showed that the pellets in phosphate-buffered saline released gentamicin continuously over 26 days. Without the simultaneous use of a systemic antibiotic, the implantation of the gentamicin-loaded pellets into the osteomyelitis region of the tibia resulted in the eradication of 81.82% of infections, as determined by microbiological, histological and radiographic evaluation, and supported the ingrowth of new bone into the tibia defects after 6 weeks of implantation. The results indicate that the gentamicin-loaded borate bioactive glass implant, combining sustained drug release with the ability to support new bone formation, could provide a method for treating osteomyelitis induced by Gram-negative bacilli. PMID:23629702

  14. Effect of TeO 2 on the elastic moduli of sodium borate glasses

    NASA Astrophysics Data System (ADS)

    Saddeek, Yasser B.; Latif, Lamia. Abd El

    2004-05-01

    Sodium borate glass containing tellurite as Te xNa 2-2 xB 4-4 xO 7-5 x with x=0, 0.05, 0.15, 0.25 and 0.35 have been prepared by rapid quenching. Ultrasonic velocity (both longitudinal and shear) measurements have been made using a transducer operated at the fundamental frequency of 4 MHz at room temperature. The density was measured by the conventional Archimedes method. The elastic moduli, the Debye temperature, Poisson's ratio, and the parameters derived from the Makishima-Mackenzie model and the bond compression model have been obtained as a function of TeO 2 content. The monotonic decrease in the velocities and the elastic moduli, and the increase in the ring diameter and the ratio Kbc/ Ke as a function of TeO 2 modifier content reveals the loose packing structure, which is attributed to the increase in the molar volume and the reduction in the vibrations of the borate lattice. The observed results confirm that the addition of TeO 2 changes the rigid character of Na 2B 4O 7 to a matrix of ionic behaviour bonds (NBOs). This is due to the creation of more and more discontinuities and defects in the glasses, thus breaking down the borax structure.

  15. Silicate and borate glasses as composite fillers: a bioactivity and biocompatibility study.

    PubMed

    Lopes, P P; Ferreira, B J M Leite; Gomes, P S; Correia, R N; Fernandes, M H; Fernandes, M H V

    2011-06-01

    Composites filled with a silicate glass (CSi) and a new borate glass (CB) were developed and compared in terms of their in vitro behaviour both in acellular and cellular media. Acellular tests were carried out in SBF and the composites were characterized by SEM-EDS, XRD and ICP. Biocompatibility studies were investigated by in vitro cell culture with MG-63 osteoblast-like and human bone marrow cells. The growth of spherical calcium phosphate aggregates was observed in acellular medium on all composite surfaces indicating that these materials became potentially bioactive. The biological assessment resulted in a dissimilar behavior of the composites. The CSi demonstrated an inductive effect on the proliferation of cells. The cells showed a normal morphology and high growth rate when compared to standard culture plates. Contrarily, inhibition of cell proliferation occurred in the CB probably due to its high degradation rate, leading to high B and Mg ionic concentration in the cell culture medium.

  16. Complex Heat Capacity of Lithium Borate Glasses Studied by Modulated DSC

    SciTech Connect

    Matsuda, Yu; Ike, Yuji; Matsui, Chihiro; Kodama, Masao; Kojima, Seiji

    2006-05-05

    Complex heat capacity, C{sub p}* = C{sub p}' - iC{sub p}'', of lithium borate glasses Li2O{center_dot}(1-x)B2O3 (x = 0.00 - 0.33) has been investigated by Modulated DSC (MDSC). We have successfully observed the frequency dependent C{sub p}* by MDSC in the frequency range 0.01 to 0.1 Hz, and the average relaxation time of glass transition has been determined as a function of temperature. Moreover, the composition dependence of the thermal properties has been investigated. The calorimetric glass transition temperatures become higher with the increase of concentration of Li2O and show the board maximum around x = 0.26-0.28. The width of glass transition region becomes narrower as Li2O increases. These results relate to the change of the fragility of the system. It has been proven that the complex heat capacity spectroscopy by MDSC is a powerful tool to investigate the glass transition phenomena.

  17. Specific features of the optical properties of potassium-aluminum borate glasses with copper chloride nanocrystals at high temperatures

    NASA Astrophysics Data System (ADS)

    Shirshnev, P. S.; Babkina, A. N.; Tsekhomskii, V. A.; Nikonorov, N. V.

    2015-09-01

    It is shown that heating of potassium-aluminum borate glasses with CuCl nanocrystals above 80°C leads to the disappearance of exciton absorption peaks, whereas cooling below 50°C gives rise to these peaks. These effects are related, respectively, to the melting of nanocrystals and crystallization of nanophase.

  18. A Novel Injectable Borate Bioactive Glass Cement as an Antibiotic Delivery Vehicle for Treating Osteomyelitis

    PubMed Central

    Cui, Xu; Gu, Yi-Fei; Jia, Wei-Tao; Rahaman, Mohamed N.; Wang, Yang; Huang, Wen-Hai; Zhang, Chang-Qing

    2014-01-01

    Background A novel injectable cement composed of chitosan-bonded borate bioactive glass (BG) particles was evaluated as a carrier for local delivery of vancomycin in the treatment of osteomyelitis in a rabbit tibial model. Materials and Methods The setting time, injectability, and compressive strength of the borate BG cement, and the release profile of vancomycin from the cement were measured in vitro. The capacity of the vancomycin-loaded BG cement to eradicate methicillin-resistant Staphylococcus aureus (MRSA)-induced osteomyelitis in rabbit tibiae in vivo was evaluated and compared with that for a vancomycin-loaded calcium sulfate (CS) cement and for intravenous injection of vancomycin. Results The BG cement had an injectability of >90% during the first 3 minutes after mixing, hardened within 30 minutes and, after hardening, had a compressive strength of 18±2 MPa. Vancomycin was released from the BG cement into phosphate-buffered saline for up to 36 days, and the cumulative amount of vancomycin released was 86% of the amount initially loaded into the cement. In comparison, vancomycin was released from the CS cement for up 28 days and the cumulative amount released was 89%. Two months post-surgery, radiography and microbiological tests showed that the BG and CS cements had a better ability to eradicate osteomyelitis when compared to intravenous injection of vancomycin, but there was no significant difference between the BG and CS cements in eradicating the infection. Histological examination showed that the BG cement was biocompatible and had a good capacity for regenerating bone in the tibial defects. Conclusions These results indicate that borate BG cement is a promising material both as an injectable carrier for vancomycin in the eradication of osteomyelitis and as an osteoconductive matrix to regenerate bone after the infection is cured. PMID:24427311

  19. Characterisation of Erbium Doped Phosphate Glass

    NASA Astrophysics Data System (ADS)

    Rasid, A. A.; Rohani, M. S.; Sahar, M. R.; Kasim, A.

    2010-03-01

    A series of erbium doped phosphate glass has been successfully fabricated, and the determination of their density and luminescence properties has been carried out. It is particularly interesting to study the effect of modifying oxides to the properties of the glass. The glass density reduces with the increasing content of Na2O. The emission spectra from luminescence spectroscopy resolved six emission peaks from the excitation wavelength of 336.8 nm (3.69 eV). The emission of 4F7/2 gives two emission peaks, where the peak near 482 nm shows a higher intensity and the peak near 491 nm gives a weak emission spectra.

  20. B K-Edge XANES of Superstructural Units in Borate Glasses

    SciTech Connect

    Sipr, O.; Simunek, A.; Rocca, F.

    2007-02-02

    The potential of x-ray absorption near-edge structure (XANES) spectroscopy for studying medium range order in borate glasses is assessed by theoretical modelling of the spectra. B K edge XANES is calculated in case that B atoms are located in isolated BO3 and BO4 units and in case that B atom are located in superstructural units of 9-15 atoms. It is found that boroxol ring and diborate and ditriborate superstructural units give rise to spectra which differ from spectra obtained by a mere superposition of spectra of isolated BO3 and BO4 units. On the other hand, spectra of pentaborate and triborate units do not differ significantly from spectra of isolated BO3 and BO4.

  1. Combination of platelet-rich plasma with degradable bioactive borate glass for segmental bone defect repair.

    PubMed

    Zhang, Ya-Dong; Wang, Gang; Sun, Yan; Zhang, Chang-Qing

    2011-02-01

    Porous scaffold biomaterials may offer a clinical alternative to bone grafts; however, scaffolds alone are typically insufficient to heal large bone defects. Numerous studies have demonstrated that osteoinductive growth factor significantly improves bone repair. In this study, a strategy combining degradable bioactive borate glass (BG) scaffolds with platelet-rich plasma (PRP) was tested. The bone defect was filled with BG alone, BG combined with autologous PRP or left empty. Bone formation was analyzed at 4, 8 and 12 weeks using both histology and radiology. The PRP treated group yielded better bone formation than the pure BG scaffold as determined by both histology and microcomputer tomography after 12 weeks. In conclusion, PRP improved bone healing in a diaphyseal rabbit model on BG. The combination of PRP and BG may be an effective approach to repair critical defects.

  2. Effect of R(3+) ions on the structure and properties of lanthanum borate glasses

    NASA Technical Reports Server (NTRS)

    Chakraborty, I. N.; Day, D. E.

    1985-01-01

    The present investigation of glass formation in the (mole percent) systems 25La2O3 (x)R2O3 (75-x)B2O3, where R = Al, Ga, and (25-x)La2O3 (x)Ln2O3 75B2O3, where Ln = Gd, Er, Y, notes that up to 25 mol pct Al2O3 or Ga2O3 can be substituted for B2O3, while no more than about 5 mol pct Ln2O3, substituted for La2O3, caused macro-phase separation. The substitution of either R2O3 or Ln2O3 in the lanthanum borate system changes the separation distance between adjacent B3O6 chains. The effect of this structural change on the molar volume, transformation temperature, thermal expansion coefficient, and transformation-range viscosity is discussed.

  3. The Development of Doped Radiosensitive Glass

    SciTech Connect

    Bradley, D. A.; Okoya, O. O.; Hugtenburg, R. P.; Hashim, Suhairul; Ramli, A. T.; Wagiran, H.; Yusoff, A. L.; Hassan, A. Aziz Mat

    2007-05-09

    For a range of industrial and medical situations there exists need for sensitive, robust high spatial resolution systems for radiation measurements. Our overall focus is on the development of doped silica-glass thermoluminescent dosimeters (TLD) with a view towards improving upon the thermoluminescence (TL) yield of commercially produced optical fibers. In baseline studies of the latter, as detailed herein, measurements have been conducted using Ge-doped communication fibers, employing sources of irradiation including bremsstrahlung x-rays (produced by a nominal accelerating potential of 50 kVp), alpha particles from an 241Am source (predominant emission 5.486 MeV) and protons of energy 2.5 MeV provided by an ion beam source. Present studies, also including elemental analysis via the PIXE and RBS techniques, permit comparison with higher TL yield doped glasses previously made by this group via the sol-gel technique and characterized in part using a range of synchrotron techniques.

  4. Magnetic behavior of erbium-zinc-borate glasses and glass ceramics

    SciTech Connect

    Borodi, G.; Pascuta, P.; Bosca, M.; Pop, V.; Stefan, R.; Tetean, R.; Radulescu, D.

    2013-11-13

    Glasses of the system (Er{sub 2}O{sub 3}){sub x}⋅(B{sub 2}O{sub 3}){sub (60−x)}⋅(ZnO){sub 40} (3 ≤ x ≤ 15 mol%) were prepared by conventional melt quenching and subsequently converted to glass ceramics by heat treatment of glass samples at 860 °C for 2 h. The magnetic behaviour of the studied glasses and glass ceramics were investigated using a vibrating sample magnetometer (VSM) and a Faraday-type magnetic balance. Magnetic data show that erbium ions are involved in negative superexchange interactions in all the investigated samples, being antiferromagnetically coupled. For all studied samples the experimental values obtained for the effective magnetic moments are lower than the value corresponding to free Er{sup 3+} ions and decrease with the increasing of Er{sub 2}O{sub 3} content. The decrease is more pronounced in heat treated samples than untreated ones.

  5. Spectroscopic analysis of a novel Nd3+-activated barium borate glass for broadband laser amplification

    NASA Astrophysics Data System (ADS)

    Vázquez, G. V.; Muñoz H., G.; Camarillo, I.; Falcony, C.; Caldiño, U.; Lira, A.

    2015-08-01

    Spectroscopic parameters of a novel Nd3+-activated barium borate (BBONd) glass have been analyzed for broadband laser amplification. The Judd-Ofelt (JO) intensity parameters were determined through a systematic analysis of the absorption spectrum of Nd3+ ions in the BBONd glass. High values of the JO intensity parameters reveal a great centro-symmetrical loss of the Nd3+ sites and high covalency degree of the ligand field. The very high Ω6 intensity parameter value makes evident both a great structural distortion of the Nd3+ sites and a strong electron-phonon coupling between Nd3+ and free OH- ions, which is consistent with the phonon energy maximum (3442.1 cm-1) recorded by Raman spectroscopy. This strong electron-phonon coupling favors high effective bandwidth and gain bandwidth values of the laser emission (4F3/2 → 4I11/2) of Nd3+ ions. The electric-dipole oscillator strengths of all the Nd3+ absorption transitions, and in particular that of the hypersensitive transition (4I9/2 → 4G5/2), are enhanced by this great structural distortion of the host. Broadband laser amplification of the 4F3/2 → 4I11/2 emission (1062 nm) of Nd3+ ions in the BBONd glass pumped at 805 nm (4I9/2 → 4F5/2 + 2H9/2) is evaluated through the main fluorescent parameters in competition with non-radiative processes. In general, the BBONd glass exhibits spectroscopic parameters comparable with those reported in the literature for broadband laser amplification into the IR region.

  6. Bone regeneration in rat calvarial defects implanted with fibrous scaffolds composed of a mixture of silicate and borate bioactive glasses.

    PubMed

    Gu, Yifei; Huang, Wenhai; Rahaman, Mohamed N; Day, Delbert E

    2013-11-01

    Previous studies have evaluated the capacity of porous scaffolds composed of a single bioactive glass to regenerate bone. In the present study, scaffolds composed of a mixture of two different bioactive glasses (silicate 13-93 and borate 13-93B3) were created and evaluated for their response to osteogenic MLO-A5 cells in vitro and their capacity to regenerate bone in rat calvarial defects in vivo. The scaffolds, which have similar microstructures (porosity=58-67%) and contain 0, 25, 50 and 100 wt.% 13-93B3 glass, were fabricated by thermally bonding randomly oriented short fibers. The silicate 13-93 scaffolds showed a better capacity to support cell proliferation and alkaline phosphatase activity than the scaffolds containing borate 13-93B3 fibers. The amount of new bone formed in the defects implanted with the 13-93 scaffolds at 12 weeks was 31%, compared to values of 25, 17 and 20%, respectively, for the scaffolds containing 25, 50 and 100% 13-93B3 glass. The amount of new bone formed in the 13-93 scaffolds was significantly higher than in the scaffolds containing 50 and 100% 13-93B3 glass. While the 13-93 fibers were only partially converted to hydroxyapatite at 12 weeks, the 13-93B3 fibers were fully converted and formed a tubular morphology. Scaffolds composed of an optimized mixture of silicate and borate bioactive glasses could provide the requisite architecture to guide bone regeneration combined with a controllable degradation rate that could be beneficial for bone and tissue healing.

  7. Melting and freezing of spherical bismuth nanoparticles confined in a homogeneous sodium borate glass

    NASA Astrophysics Data System (ADS)

    Kellermann, G.; Craievich, A. F.

    2008-08-01

    The melting temperature and the crystallization temperature of Bi nanoclusters confined in a sodium borate glass were experimentally determined as functions of the cluster radius. The results indicate that, on cooling, liquid Bi nanodroplets exhibit a strong undercooling effect for a wide range of radii. The difference between the melting temperature and the freezing temperature decreases for decreasing radius and vanishes for Bi nanoparticles with a critical radius R=1.9nm . The magnitude of the variation in density across the melting and freezing transitions for Bi nanoparticles with R=2nm is 40% smaller than for bulk Bi. These experimental results support a basic core-shell model for the structure of Bi nanocrystals consisting of a central crystalline volume surrounded by a structurally disordered shell. The volume fraction of the crystalline core decreases for decreasing nanoparticle radius and vanishes for R=1.9nm . Thus, on cooling, the liquid nanodroplets with R<1.9nm preserve, across the liquid-to-solid transformation, their homogeneous and disordered structure without crystalline core.

  8. Luminescence properties of Tm3+/Yb3+ codoped lead alumina bismuth borate glasses

    NASA Astrophysics Data System (ADS)

    Goud, K. Krishna Murthy; Reddy, M. Chandra Shekhar; Rao, B. Appa

    2016-05-01

    This paper reports on the spectroscopic properties of Yb3+ and Tm3+ codoped lead alumina bismuth borate glasses. Optical absorption spectra of these Samples were recorded at room temperature in the wavelength range 350-2000 nm. The absorption spectra exhibited the bands at 658 nm (3H6→3F2), 686 nm (3H6→3F3), 792 nm (3H6→3H4), 1211 nm (3H6→3H5) and 1663 nm (3H6→3F4) due to Tm3+ ions. The band at 977 nm (2F7/2→2F5/2) is due to Yb3+ ions. Optical band gap (Eopt) and Urbach energy (ΔE) values were calculated from the spectra. It was observed that the value of optical band gap decreases with increase in the concentration of Tm3+ ions. The upconversion luminescence spectra were measured under excitation of 980 nm laser diode, and the intense blue (470 nm) and green (656 nm) emission were simultaneously observed at room temperature. A proposed upconversion mechanism involving energy transfer from Yb3+ to Tm3+ has been presented.

  9. Effect of TiO2 on the optical, structural and crystallization behavior of barium borate glasses

    NASA Astrophysics Data System (ADS)

    Marzouk, M. A.; ElBatal, F. H.; ElBatal, H. A.

    2016-07-01

    Collective characterizations of prepared binary barium borate glass (50 mol % BaO - 50 mol % B2O3) together with samples containing increasing added TiO2 contents (5% → 30%) were carried out by optical and FT infrared absorption measurements. FT infrared and X-ray diffraction analysis were done for heat treated glass - ceramic derivatives prepared through two step regime process. Optical spectra of the glasses reveal the presence of titanium ions mainly in the tetravalent state imparting additional UV band beside strong UV absorption due to trace iron impurity. IR spectral studies indicate the presence of triangular and tetrahedral borate groups through the modification of BaO to some BO3 to BO4 groups beside the presence of titanium ions as interfering or overlapping TiO4 or Bsbnd Osbnd Ti groupings in the glassy network. Crystalline X-ray diffraction results indicate the separation of crystalline barium borate of the composition (2BaO.5 B2O3) as a main constituent together with some crystalline alkali titanates confirming the role of TiO2 of both as nucleating agent beside acting as structural forming through reaction with alkali oxides to form crystalline titanates. The optical band gap values reveal progressive decrease and increase of Urbach energy with TiO2 content and the same for the refractive index values and all these parameters are correlated with the proposed changes in the glass constitution with the introduction of TiO2. The additional thermal expansion measurements indicate the peculiar characteristic negative expansion up to 300 °C and after which an increase in the coefficient of thermal expansion is identified with the increase in temperature. The thermal parameters are also correlated with the modification of the glass structure by the introduction of titanium ions.

  10. Concentration dependent spectroscopic properties of Dy3+ ions doped boro-phosphate glasses

    NASA Astrophysics Data System (ADS)

    Mariyappan, M.; Marimuthu, K.

    2016-05-01

    Dy3+ ions doped boro-phosphate glasses have been synthesized by melt quenching method and characterized through FTIR, absorption and luminescence spectral measurements. The presence of various stretching and bending vibrations of different borate and phosphate groups were identified from the FTIR spectra. In order to examine the electronic band structure of the studied glasses, Optical energy gap (Eopt) and Urbach energy (ΔE) values were estimated from the absorption spectra. The Judd-Ofelt (JO) intensity parameters were calculated to examine the symmetry of the ligand environment around the Dy3+ ions site. The emission spectra exhibit two intense emission bands at around 482 nm (blue) and 574 nm (yellow) corresponding to the 4F9/2→6H15/2 and 4F9/2→6H13/2 transitions respectively. The emission spectra were characterized through Commission International d'Eclairage (CIE) 1931 chromaticity diagram to explore its suitability for WLED applications.

  11. Electronic polarizability and interaction parameter of gadolinium tungsten borate glasses with high WO{sub 3} content

    SciTech Connect

    Taki, Yukina; Shinozaki, Kenji; Honma, Tsuyoshi; Dimitrov, Vesselin; Komatsu, Takayuki

    2014-12-15

    Glasses with the compositions of 25Gd{sub 2}O{sub 3}–xWO{sub 3}–(75−x)B{sub 2}O{sub 3} with x=25–65 were prepared by using a conventional melt quenching method, and their electronic polarizabilities, optical basicities Λ(n{sub o}), and interaction parameters A(n{sub o}) were estimated from density and refractive index measurements in order to clarify the feature of electronic polarizability and bonding states in the glasses with high WO{sub 3} contents. The optical basicity of the glasses increases monotonously with the substitution of WO{sub 3} for B{sub 2}O{sub 3}, and contrary the interaction parameter decreases monotonously with increasing WO{sub 3} content. A good linear correlation was observed between Λ(n{sub o}) and A(n{sub o}) and between the glass transition temperature and A(n{sub o}). It was proposed that Gd{sub 2}O{sub 3} oxide belongs to the category of basic oxide with a value of A(n{sub o})=0.044 Å{sup −3} as similar to WO{sub 3}. The relationship between the glass formation and electronic polarizability in the glasses was discussed, and it was proposed that the glasses with high WO{sub 3} and Gd{sub 2}O{sub 3} contents would be a floppy network system consisting of mainly basic oxides. - Graphical abstract: This figure shows the correlation between the optical basicity and interaction parameter in borate-based glasses. The data obtained in the present study for Gd{sub 2}O{sub 3}–WO{sub 3}–B{sub 2}O{sub 3} glasses are locating in the correlation line for other borate glasses. These results shown in Fig. 8 clearly demonstrate that Gd{sub 2}O{sub 3}–WO{sub 3}–B{sub 2}O{sub 3} glasses having a wide range of optical basicity and interaction parameter are regarded as glasses consisting of acidic and basic oxides. - Highlights: • Gd{sub 2}O{sub 3}–WO{sub 3}–B{sub 2}O{sub 3} glasses with high WO{sub 3} contents were prepared. • Electronic polarizability and interaction parameter were estimated. • Optical basicity increases

  12. Structure of Alkali Borate Glasses at High Pressure: B and Li K-Edge Inelastic X-Ray Scattering Study

    SciTech Connect

    Lee, Sung Keun; Eng, Peter J.; Mao, Ho-kwang; Meng, Yue; Shu, Jinfu

    2008-06-16

    We report the first in situ boron K-edge inelastic x-ray scattering (IXS) spectra for alkali borate glasses (Li{sub 2}B{sub 4}O{sub 7}) at high pressure up to 30 GPa where pressure-induced coordination transformation from three-coordinated to four-coordinated boron was directly probed. Coordination transformation (reversible upon decompression) begins around 5 GPa and the fraction of four-coordinated boron increases with pressure from about 50% (at 1 atm) to more than 95% (at 30 GPa) with multiple densification mechanisms, evidenced by three distinct pressure ranges for (d{sup [4]}B/dP){sub T}. The lithium K-edge IXS spectrum for Li-borate glasses at 5 GPa shows IXS features similar to that at 1 atm, suggesting that the Li environment does not change much with pressure up to 5 GPa. These results provide improved understanding of the structure of low-z glass at high pressure.

  13. IR luminescence in bismuth-doped germanate glasses and fibres

    SciTech Connect

    Pynenkov, A A; Firstov, Sergei V; Panov, A A; Firstova, E G; Nishchev, K N; Bufetov, Igor' A; Dianov, Evgenii M

    2013-02-28

    We have studied the optical properties of lightly bismuth doped ({<=}0.002 mol %) germanate glasses prepared in an alumina crucible. The glasses are shown to contain bismuth-related active centres that have been identified previously only in bismuth-doped fibres produced by MCVD. With increasing bismuth concentration in the glasses, their luminescence spectra change markedly, which is attributable to interaction between individual bismuth centres. (optical fibres)

  14. Role of electron transfer in Ce{sup 3+} sensitized Yb{sup 3+} luminescence in borate glass

    SciTech Connect

    Sontakke, Atul D. Katayama, Yumiko; Zhuang, Yixi; Tanabe, Setsuhisa; Ueda, Jumpei; Dorenbos, Pieter

    2015-01-07

    In a Ce{sup 3+}-Yb{sup 3+} system, two mechanisms are proposed so far namely, the quantum cutting mechanism and the electron transfer mechanism explaining Yb{sup 3+} infrared luminescence under Ce{sup 3+} excitation. Among them, the quantum cutting mechanism, where one Ce{sup 3+} photon (ultraviolet/blue) gives rise to two Yb{sup 3+} photons (near infrared) is widely sought for because of its huge potential in enhancing the solar cell efficiency. In present study on Ce{sup 3+}-Yb{sup 3+} codoped borate glasses, Ce{sup 3+} sensitized Yb{sup 3+} luminescence at ∼1 μm have been observed on Ce{sup 3+} 5d state excitation. However, the intensity of sensitized Yb{sup 3+} luminescence is found to be very weak compared to the strong quenching occurred in Ce{sup 3+} luminescence in Yb{sup 3+} codoped glasses. Moreover, the absolute luminescence quantum yield also showed a decreasing trend with Yb{sup 3+} codoping in the glasses. The overall behavior of the luminescence properties and the quantum yield is strongly contradicting with the quantum cutting phenomenon. The results are attributed to the energetically favorable electron transfer interactions followed by Ce{sup 3+}-Yb{sup 3+} ⇌ Ce{sup 4+}-Yb{sup 2+} inter-valence charge transfer and successfully explained using the absolute electron binding energies of dopant ions in the studied borate glass. Finally, an attempt has been presented to generalize the electron transfer mechanism among opposite oxidation/reduction property dopant ions using the vacuum referred electron binding energy (VRBE) scheme for lanthanide series.

  15. Synthesis and photoluminescence properties of Pb2+ doped inorganic borate phosphor NaSr4(BO3)3

    NASA Astrophysics Data System (ADS)

    Chauhan, A. O.; Koparkar, K. A.; Bajaj, N. S.; Omanwar, S. K.

    2016-05-01

    A series of Inorganic borate phosphors NaSr4(BO3)3 doped with Pb2+ was successfully synthesized by modified solid state diffusion method. The crystal structure and the phase purity of sample were characterized by powder X-ray diffraction (XRD). The photoluminescence properties of synthesized materials were investigated using spectrofluorometer at room temperature. The phosphor show strong broad band emission spectra in UVA region maximum at 370 nm under the excitation of 289 nm. The dependence of the emission intensity on the Pb2+ concentration for the NaSr4(BO3)3 were studied in details. The concentration quenching of Pb2+ doped NaSr4(BO3)3 was observed at 0.02 mol. The Stokes shifts of NaSr4(BO3)3: Pb2+ phosphor was calculated to be 7574 cm-1.

  16. Effect of pyrophosphate ions on the conversion of calcium–lithium–borate glass to hydroxyapatite in aqueous phosphate solution

    PubMed Central

    Fu, Hailuo; Day, Delbert E.; Huang, Wenhai

    2010-01-01

    The conversion of glass to a hydroxyapatite (HA) material in an aqueous phosphate solution is used as an indication of the bioactive potential of the glass, as well as a low temperature route for preparing biologically useful materials. In this work, the effect of varying concentrations of pyrophosphate ions in the phosphate solution on the conversion of a calcium–lithium–borate glass to HA was investigated. Particles of the glass (150–355 µm) were immersed for up to 28 days in 0.25 M K2HPO4 solution containing 0–0.1 M K4P2O7. The kinetics of degradation of the glass particles and their conversion to HA were monitored by measuring the weight loss of the particles and the ionic concentration of the solution. The structure and composition of the conversion products were analyzed using X-ray diffraction, scanning electron microscopy, and Fourier transform infrared spectroscopy. For K4P2O7 concentrations of up to 0.01 M, the glass particles converted to HA, but the time for complete conversion increased from 2 days (no K4P2O7) to 10 days (0.01 M K4P2O7). When the K4P2O7 concentration was increased to 0.1 M, the product consisted of an amorphous calcium phosphate material, which eventually crystallized to a pyrophosphate product (predominantly K2CaP2O7 and Ca2P2O7). The consequences of the results for the formation of HA materials and devices by the glass conversion route are discussed. PMID:20680413

  17. Kinetics and mechanisms of the conversion of silicate (45S5), borate, and borosilicate glasses to hydroxyapatite in dilute phosphate solutions.

    PubMed

    Huang, Wenhai; Day, Delbert E; Kittiratanapiboon, Kanisa; Rahaman, Mohamed N

    2006-07-01

    Bioactive glasses with controllable conversion rates to hydroxyapatite (HA) may provide a novel class of scaffold materials for bone tissue engineering. The objective of the present work was to comprehensively characterize the conversion of a silicate bioactive glass (45S5), a borate glass, and two intermediate borosilicate glass compositions to HA in a dilute phosphate solution at 37 degrees Celsius. The borate glass and the borosilicate glasses were derived from the 45S5 glass by fully or partially replacing the SiO(2) with B(2)O(3). Higher B(2)O(3) content produced a more rapid conversion of the glass to HA and a lower pH value of the phosphate solution. Whereas the borate glass was fully converted to HA in less than 4 days, the silicate (45S5) and borosilicate compositions were only partially converted even after 70 days, and contained residual SiO(2) in a Na-depleted core. The concentration of Na(+) in the phosphate solution increased with reaction time whereas the PO(4) (3-) concentration decreased, both reaching final limiting values at a rate that increased with the B(2)O(3) content of the glass. However, the Ca(2+) concentration in the solution remained low, below the detection limit of atomic absorption, throughout the reaction. Immersion of the glasses in a mixed solution of K(2)HPO(4) and K(2)CO(3) produced a carbonate-substituted HA but the presence of the K(2)CO(3) had little effect on the kinetics of conversion to HA. The kinetics and mechanisms of the conversion process of the four glasses to HA are compared and used to develop a model for the process.

  18. Nano crystalline Bi2(VO5) phases in lithium bismuth borate glasses containing mixed vanadium-nickel oxides

    NASA Astrophysics Data System (ADS)

    Yadav, Arti; Khasa, S.; Dahiya, M. S.; Agarwal, A.

    2016-05-01

    Glass composition 7V2O5.23Li2O.20Bi2O3.50B2O3 and x(2NiO.V2O5).(30-x)Li2O.20Bi2O3.50B2O3, x=0, 2, 5, 7 and 10, were produced by conventional melt quenching technique. The quenched amorphous glass samples were annealed at temperatures 400°C and 500°C for 6 hours. The Bi2(VO5) crystallite were grown in all prepared glass matrix. Tn vanadium lithium bismuth borate glass (annealed), the some phrase of V2O5-crystal were observed along with the nano crystalline Bi2(VO5) phase. The sharp peaks in FTTR spectra of all annealed compositions were also compatible with the XRD diffraction peaks of the system under investigation. Average crystalline size (D) of the Bi2(VO5) nano-crystallite was ~30nm for samples annealed at 400°C and ~42nm for samples annealed at 500°C. Lattice parameter and the lattice strain for all the samples was also calculated corresponding to the (113) plane of Bi2(VO5) crystallite.

  19. Effect of zinc-borate glass addition on the thermal properties of the cordierite/Al2O3 composites containing nano-sized spinel crystal.

    PubMed

    Jo, Sinae; Kang, Seunggu

    2013-11-01

    Low-melting zinc-borate glass was added to the cordierite/Al2O3 composite in order to improve the sintering facility of Al2O3 and formation of nano-sized spinel crystal of high thermal conductivity. Increasing the ZnO/B2O3 ratio in the zinc-borate glass increased the ZnAl2O4 spinel and decreased the Al4B2O9 crystal peak intensities in X-ray diffraction pattern. The XRD peak intensities of the ZnAl2O4 spinel and Al4B2O9 crystals in the specimen containing 10 wt% zinc-borate glass (10G series) are higher than that of the specimen containing 5 wt% zinc-borate glass (5G series). The microstructures of most 10G series specimens had the flower-shaped crystal which was composed of 50 nm wide and 250 nm long needle-like crystals and identified as ZnAl2O4 spinel phase. The thermal conductivity of the 10G series specimen was higher than that of the 5G series in any ZnO/B2O3 ratio due to the formation of plenty of nano-sized ZnAl2O4 spinel of high thermal conductivity. Particularly, the thermal conductivity of the cordierite/Al2O3 composite containing 10 wt% zinc-borate glass of ZnO/B2O3 weight ratio = 1.5 was 3.8 W/Km which is much higher than that of the published value (3.0 W/Km).

  20. Structural and optical properties of Dy3+ doped Aluminofluoroborophosphate glasses for white light applications

    NASA Astrophysics Data System (ADS)

    Vijayakumar, M.; Mahesvaran, K.; Patel, Dinesh K.; Arunkumar, S.; Marimuthu, K.

    2014-11-01

    Dy3+ doped Aluminofluoroborophosphate glasses (BPAxD) have been prepared following conventional melt quenching technique and their structural and optical properties were explored through XRD, FTIR, optical absorption, excitation, emission and decay measurements. The coexistence of BO3 groups in borate rich domain and BO4 groups in phosphate rich domain have been confirmed through vibrational energy analysis. Negative bonding parameter (δ) values indicate that, the metal-ligand environment in the prepared glasses is of ionic in nature. The oscillator strength and the luminescent intensity Ωλ (λ = 2, 4 and 6) parameters are calculated using Judd-Ofelt theory. The radiative properties such as transition probability (A), stimulated emission cross-section (σpE) and branching ratios (β) have been calculated using JO intensity parameters and compared with the reported Dy3+ doped glasses. Concentration effect on Y/B intensity ratios and the CIE chromaticity coordinates were calculated for the generation of white light from the luminescence spectra. The color purity and the correlated color temperature were also calculated and the results are discussed in the present work. The decay of the 4F9/2 excited level is found to be single exponential for lower concentration and become non-exponential for higher concentration. The non-exponential behavior arises due to the efficient energy transfer between the Dy3+ ions through various non-radiative relaxation channels and the decay of the 4F9/2 excited level have been analyzed with IH model. Among the prepared glasses, BPA0.5D glass exhibits higher σpE, βR, σpE×σpE, σpE×Δλeff and η values for the 6H13/2 emission band which in turn specifies its suitability for white LEDs, laser applications and optical amplifiers.

  1. Optical and infrared absorption spectra of 3d transition metal ions-doped sodium borophosphate glasses and effect of gamma irradiation.

    PubMed

    Abdelghany, A M; ElBatal, F H; Azooz, M A; Ouis, M A; ElBatal, H A

    2012-12-01

    Undoped and transition metals (3d TM) doped sodium borophosphate glasses were prepared. UV-visible absorption spectra were measured in the region 200-900nm before and after gamma irradiation. Experimental optical data indicate that the undoped sodium borophosphate glass reveals before irradiation strong and broad UV absorption and no visible bands could be identified. Such UV absorption is related to the presence of unavoidable trace iron impurities within the raw materials used for preparation of this base borophosphate glass. The TMs-doped glasses show absorption bands within the UV and/or visible regions which are characteristic to each respective TM ion in addition to the UV absorption observed from the host base glass. Infrared absorption spectra of the undoped and TMs-doped glasses reveal complex FTIR consisting of extended characteristic vibrational bands which are specific for phosphate groups as a main constituent but with the sharing of some vibrations due to the borate groups. This criterion was investigated and approved using DAT (deconvolution analysis technique). The effects of different TMs ions on the FTIR spectra are very limited due to the low doping level (0.2%) introduced in the glass composition. Gamma irradiation causes minor effect on the FTIR spectra specifically the decrease of intensities of some bands. Such behavior is related to the change of bond angles and/or bond lengths of some structural building units upon gamma irradiation.

  2. Photon-conversion and sensitization evaluation of Eu³⁺ in a borate glass system.

    PubMed

    Tian, Y M; Shen, L F; Pun, E Y B; Lin, H

    2016-02-20

    Photon conversion is exhibited in a borate (LKZBSB) glass system containing Eu(3+), and the enhanced characteristic emissions of Eu(3+) with the codoping of Ce(3+) have been verified. A large Judd-Ofelt intensity parameter Ω2 of Eu(3+) indicates a high asymmetrical and strong covalent environment around rare-earth (RE) ions in LKZBSB glasses and spontaneous emission probability and a maximum emission cross section of the dominant 5D0→7F2 transition were derived to be 370  s(-1) and 1.28×10(-21)  cm2, respectively, revealing the potential UV→visible photon-conversion capacity of Eu(3+). Absolutely quantitative evaluation illustrates that Eu(3+) is a favorable photon-conversion center to achieve high photon-conversion efficiency. The addition of Ce(3+) is beneficial to realizing effective red emission of Eu(3+), which possesses commercial value by decreasing the dopant of expensive europium compounds. As an expectation, this photon-conversion LKZBSB glass system can promote the development of a photon downconversion layer for solar cells, which are particularly used in outer space with intense UV radiation. PMID:26906599

  3. Fluorescent properties of Tb-doped borosilicate glass films prepared by a sol-gel method

    NASA Astrophysics Data System (ADS)

    Tonooka, Kazuhiko; Shimokawa, Katsuyoshi; Nishimura, Okio

    2001-04-01

    Rare earth elements have been used as optical dopants in glasses for many years. Boro-silicate glass films doped with rare-earths were deposited on glass substrates by using a simple sol-gel method. To avoid the undesirable precipitation due to the different hydrolysis rates between silicon and boron alkoxides, two solutions were used for dip-coating separately. One solution consisted of silicon tetraethoxide, ethanol, water and terbium nitrate as the Tb dopant. Another consisted of triethyl borate. Layer-by-layer deposition was applied by dipping into solutions containing metal alkoxides in sequence. The fluorescence properties of Tb3+ were investigated for the boro-silicate samples in relation to the firing effect. As-deposited silicate and boro-silicate samples showed similar fluorescence spectra under UV excitation. After firings at about 800 degrees C, a remarkable increase of the Tb3+-ion fluorescence was observed for the boro-silicate samples, while the silicate sample showed a little increase in fluorescence intensity. These experimental results suggested the formation of boro- silicate network and the incorporation of Tb3+ into the boro-silicate matrix. The multilayer process was found useful to fabricate multi-component sol-gel films.

  4. Structural and luminescence behavior of Er(3+) ions doped Barium tellurofluoroborate glasses.

    PubMed

    Annapoorani, K; Maheshvaran, K; Arunkumar, S; Suriya Murthy, N; Marimuthu, K

    2015-01-25

    Er(3+) doped Barium tellurofluoroborate glasses (BTFBxE) with the chemical composition (30-x)TeO2+30B2O3+20BaO+20BaF+xEr2O3 (where x=0.01, 0.05, 0.1, 0.5, 1.0 and 2.0 in wt%) were prepared following the melt quenching technique. The different vibrational modes of borates and tellurites in the prepared glasses were explored through FTIR and Raman spectra. The optical absorption spectra have been used to determine the ionic/covalent nature of the metal-ligand bond in the prepared glasses with the help of Nephelauxetic ratio (β) and bonding parameter (δ) studies. The optical band gap of direct and indirect allowed transitions were determined from Tauc's plot and the variations of band gap energy with structural arrangements were discussed. The Urbach energy values were determined and the relatively lower values of the Urbach's energy reveal the minimal degree of disorderness in the prepared glasses. The oscillator strengths (fexp and fcal) and Judd-Ofelt (JO) intensity parameters (Ω2, Ω4 and Ω6) were calculated with the application of JO theory and the trends of the JO intensity parameters are found to be Ω2>Ω6>Ω4 for all the prepared glasses with a minimum variation in Ω2 intensity parameter values. A bright green emission was observed from the (2)H11/2+(4)S3/2→ (4)I15/2 transition and the radiative properties such as transition probability (A), stimulated emission cross-section (σP(E)), branching ratio (βr) and radiative lifetime (τ) were calculated using the JO parameters. The suitability of the prepared glasses for the fabrication of photonic devices were also discussed and reported in the present work.

  5. Structural and luminescence behavior of Er3+ ions doped Barium tellurofluoroborate glasses

    NASA Astrophysics Data System (ADS)

    Annapoorani, K.; Maheshvaran, K.; Arunkumar, S.; Suriya Murthy, N.; Marimuthu, K.

    2015-01-01

    Er3+ doped Barium tellurofluoroborate glasses (BTFBxE) with the chemical composition (30 - x)TeO2 + 30B2O3 + 20BaO + 20BaF + xEr2O3 (where x = 0.01, 0.05, 0.1, 0.5, 1.0 and 2.0 in wt%) were prepared following the melt quenching technique. The different vibrational modes of borates and tellurites in the prepared glasses were explored through FTIR and Raman spectra. The optical absorption spectra have been used to determine the ionic/covalent nature of the metal-ligand bond in the prepared glasses with the help of Nephelauxetic ratio (β) and bonding parameter (δ) studies. The optical band gap of direct and indirect allowed transitions were determined from Tauc's plot and the variations of band gap energy with structural arrangements were discussed. The Urbach energy values were determined and the relatively lower values of the Urbach's energy reveal the minimal degree of disorderness in the prepared glasses. The oscillator strengths (fexp and fcal) and Judd-Ofelt (JO) intensity parameters (Ω2, Ω4 and Ω6) were calculated with the application of JO theory and the trends of the JO intensity parameters are found to be Ω2 > Ω6 > Ω4 for all the prepared glasses with a minimum variation in Ω2 intensity parameter values. A bright green emission was observed from the 2H11/2 + 4S3/2 → 4I15/2 transition and the radiative properties such as transition probability (A), stimulated emission cross-section (σPE), branching ratio (βr) and radiative lifetime (τ) were calculated using the JO parameters. The suitability of the prepared glasses for the fabrication of photonic devices were also discussed and reported in the present work.

  6. Experimental insights on the electron transfer and energy transfer processes between Ce{sup 3+}-Yb{sup 3+} and Ce{sup 3+}-Tb{sup 3+} in borate glass

    SciTech Connect

    Sontakke, Atul D. Katayama, Yumiko; Tanabe, Setsuhisa; Ueda, Jumpei; Dorenbos, Pieter

    2015-03-30

    A facile method to describe the electron transfer and energy transfer processes among lanthanide ions is presented based on the temperature dependent donor luminescence decay kinetics. The electron transfer process in Ce{sup 3+}-Yb{sup 3+} exhibits a steady rise with temperature, whereas the Ce{sup 3+}-Tb{sup 3+} energy transfer remains nearly unaffected. This feature has been investigated using the rate equation modeling and a methodology for the quantitative estimation of interaction parameters is presented. Moreover, the overall consequences of electron transfer and energy transfer process on donor-acceptor luminescence behavior, quantum efficiency, and donor luminescence decay kinetics are discussed in borate glass host. The results in this study propose a straight forward approach to distinguish the electron transfer and energy transfer processes between lanthanide ions in dielectric hosts, which is highly advantageous in view of the recent developments on lanthanide doped materials for spectral conversion, persistent luminescence, and related applications.

  7. Probing and modeling of pressure-induced coordination transformation in borate glasses: Inelastic x-ray scattering study at high pressure

    SciTech Connect

    Lee, Sung Keun; Eng, Peter J.; Mao, Ho-kwang; Shu, Jinfu

    2009-01-15

    Here, we report on the in situ synchrotron inelastic x-ray scattering spectra of Na-borate glasses at high pressure up to 25 GPa. The pressure-induced boron coordination transformation from {sup [3]}B to {sup [4]}B is linear with pressure characterized by a single value of ({partial_derivative}{sup [3]}B/{partial_derivative}P){sub T}. Previous studies of Li-borate and pure-borate glasses show a nonlinear transformation with multiple ({partial_derivative}{sup [3]}B/{partial_derivative}P){sub T} values for different pressure ranges, revealing the important role cation field strength plays in densification and pressure-induced structural changes. Considering the distribution of the energy difference beween low- and high-pressure states ({Delta}{var_epsilon}) in the energy landscape and the variance of the ratio {Delta}{var_epsilon} to its pressure gradient ({partial_derivative}{Delta}{var_epsilon}/{partial_derivative}P){sub T} as a measure of network flexibility with pressure, an amorphous system with a large variance in {Delta}{var_epsilon} at 1 atm and/or a small ({partial_derivative}{Delta}{var_epsilon}/{partial_derivative}P){sub T} may undergo a gradual coordination transformation (e.g., Na borates). In contrast, a system with the opposite behavior (e.g., Li borates) undergoes an abrupt coordination transformation. The results and concepts of this study thus can shed light on opportunities to study the effect of composition on the nature of densification in low-z oxide and other archetypal glasses and melts.

  8. Optical absorption and fluorescence properties of Er{sup 3+}/Yb{sup 3+} codoped lead bismuth alumina borate glasses

    SciTech Connect

    Goud, K. Krishna Murthy Reddy, M. Chandra Shekhar Rao, B. Appa

    2014-04-24

    Lead bismuth alumina borate glasses codoped with Er{sup 3+}/Yb{sup 3+} were prepared by melt quenching technique. Optical absorption, FTIR and photoluminescence spectra of these glasses have been studied. Judd-Ofelt theory has been applied to to the f ↔ f transitions for evaluating Ω{sub 2}, Ω{sub 4} and Ω{sub 6} parameters. Radiative properties like branching ratio β{sub r} and the radiative life time τ{sub R} have been determined on the basis of Judd-Ofelt theory. Upconversion emissions have been observed under 980nm laser excitation at room temperature. Green and red up-conversion emissions are centered at 530, 550 and 656 nm corresponding to {sup 2}H{sub 11/2}→{sup 4}I{sub 15/2}, {sup 4}S{sub 3/2}→{sup 4}I{sub 15/2} and {sup 4}F{sub 9/2}→{sup 4}I{sub 15/2} transitions of Er{sup 3+} respectively. The results obtained are discussed quantitatively based on the energy transfer between Yb{sup 3+} and Er{sup 3+}.

  9. Spectral investigations of Sm{sup 3+}-doped oxyfluorosilicate glasses

    SciTech Connect

    Ramachari, D.; Rama Moorthy, L.; Jayasankar, C.K.

    2013-09-01

    Graphical abstract: The figure shows the emission spectra of Sm{sup 3+} doped KNSZL glass for different concentrations. Among the four emission transitions {sup 4}G{sub 5/2} → {sup 6}H{sub 5/2}, {sup 4}G{sub 5/2} → {sup 6}H{sub 7/2}, {sup 4}G{sub 5/2} → {sup 6}H{sub 9/2} and {sup 4}G{sub 5/2} → {sup 6}H{sub 11/2}, the {sup 4}G{sub 5/2} → {sup 6}H{sub 7/2} transition of KNSZLSm10 glass is more intense compared with all the transitions. The insert figure shows, the color coordinates (0.59, 0.41) of KNSZLSm10 glass is located on the perimeter of the chromaticity diagram at 592 nm which appears to be closest to the orange color. From these results the KNSZLSm10 glass could be useful for optical amplifiers, waveguides, telecommunications and orange LEDs. - Highlights: • From the DTA, the undoped KNSZL glass more precisely in fiberdrawing. • The XRD pattern confirmed the KNbO{sub 3} nanocrystallites of undoped KNSZL glass. • FTIR and Raman data of KNSZLSm10 glass revealed structural properties. • Judd–Ofelt analysis and decay measurements were carried out. • The optical gain parameter of the investigated glass is 18.13 × 10{sup −25} cm{sup 2} s. - Abstract: Sm{sub 2}O{sub 3}-doped oxyfluorosilicate glasses were prepared by melt-quenching method. The differential thermal analysis and X-ray diffraction were carried out to investigate the glass transition temperature and structure of precursor glass. Infrared spectroscopy, Raman, optical absorption, photoluminescence and decay measurements were carried out for Sm{sup 3+}-doped oxyfluorosilicate glasses. From the absorption spectrum, the Judd–Ofelt intensity parameters have been evaluated to predict the radiative properties for the emission levels of Sm{sup 3+} ions. The lifetimes of {sup 4}G{sub 5/2} level are found to decrease from 1.17 to 0.93 ms due to the energy transfer, when the concentration of Sm{sup 3+} ions increases from 0.1 to 2.0 mol%. The optical gain parameter (18.13 × 10{sup −25

  10. Neptunium concentrations in solutions contacting actinide-doped glass

    SciTech Connect

    Rai, D.; McVay, G.L.; Strickert, R.G.

    1982-07-01

    To help predict concentrations of neptunium leached from nuclear waste repositories in geologic environments, the solubility of neptunium in a neptunium-doped borosilicate glass, which simulates a high-level waste glass, was investigated. The concentrations of neptunium in solutions contacting the crushed doped glass were found to be controlled by a neptunium solid phase that is similar to crystalline(c) NpO/sub 2/ in solubility. Thus, the maximum concentration of the neptunium leached from this waste form can be predicted from the solubility of NpO/sub 2/(c). This conclusion is based on similar neptunium concentrations in solutions contacting neptunium-doped glass, neptunium-doped glass plus NpO/sub 2/(c), and NpO/sub 2/(c) alone, under controlled redox potentials and a range of pH values. The quinhydrone used in this study was found to be a very effective redox buffer (the approximate pe + pH = 11.8). The predictions based on the thermodynamic data and the solvent extraction tests showed Np(V) to be the primary oxidation state in solution.

  11. Optical phase conjugation in semiconductor-doped glasses

    NASA Astrophysics Data System (ADS)

    Roussignol, P.; Ricard, D.; Rustagi, K. C.; Flytzanis, C.

    1985-08-01

    We have studied optical phase conjugation in two types of semiconductor-doped glasses. Corning 3.68 and Schott OG 530 at λ = 0.532 μm using picosecond pulses. We observe a slow nonlinearity in agreement with the slow decay of luminescence. The saturation of the reflectivity is strongly correlated with the absorption saturation of these glasses and may be interpreted in terms of a three-level system model.

  12. Photostimulated luminescence from BaCl{sub 2}:Eu{sup 2+} nanocrystals in lithium borate glasses following neutron irradiation

    SciTech Connect

    Appleby, G. A.; Edgar, A.; Williams, G. V. M.; Bos, A. J. J.

    2006-09-04

    A glass-ceramic thermal neutron imaging plate material is reported. The material consists of a neutron sensitive 2B{sub 2}O{sub 3}-Li{sub 2}O glass matrix containing nanocrystallites of the storage phosphor BaCl{sub 2}:Eu{sup 2+}. When doped with 0.5 mol % Eu{sup 2+}, the neutron induced photostimulated luminescence (PSL) conversion efficiency of the {sup 10}B enriched glass-ceramic is around 60% of that a commercial neutron imaging plate, while the {gamma} sensitivity is an order of magnitude lower than that of the commercial plate. A Eu{sup 2+}-concentration series shows that the PSL efficiency for x rays is optimized at 0.01 mol % Eu{sup 2+}. Thermoluminescence measurements indicate trap depths in BaCl{sub 2}:Eu{sup 2+} ranging from 0.55 to 2.7 eV.

  13. White light generation from Dy3+ doped tellurite glass

    NASA Astrophysics Data System (ADS)

    Damak, Kamel; Yousef, El Sayed; Rüssel, Christian; Maâlej, Ramzi

    2014-02-01

    This paper reports on the spectral results of Dy3+ (1.0 mol%) ions-doped TeO2-ZnO-PbO-PbF2-Na2O (TZPPN) glass. Raman spectrum measurements, differential thermal analysis (DTA) profiles of this rare-earth ion-doped glass were carried out. From the DTA thermogram, glass transition (Tg), crystallization (Tc) and melting (Tm) temperatures were evaluated. Direct and indirect optical band gaps were calculated based on the glasses UV absorption spectra. From the absorption spectra, Judd-Ofelt (J-O) intensity parameters, Ωk, were calculated. Using J-O intensity parameters, several radiative properties such as spontaneous transition probabilities (AR), radiative branching ratios (βR) and radiative lifetimes (τR) were determined for the excitation level 4F9/2. From the emission spectra, a strong yellow emission at 574 nm (4F9/2→6H13/2) was observed and it also showed a combination of blue and red emission bands for this glass. The stimulated emission cross-section σ(λp) was also evaluated for the 4F9/2→6HJ (J=11/2, 13/2, and 15/2) transitions. This study indicates that 1 mol% Dy2O3-doped tellurite glass can be considered for white light generation with the excitation of blue light (454 nm).

  14. Luminescence properties of Sm3+-doped fluorosilicate glasses

    NASA Astrophysics Data System (ADS)

    Linganna, K.; Basavapoornima, Ch.; Jayasankar, C. K.

    2015-06-01

    Sm2O3-doped fluorosilicate glasses (SiO2+Nb2O5+K2O+ZnF2) were prepared by the melt quenching technique and are characterized through various spectroscopic techniques such as Raman, optical absorption, excitation, emission and decay to derive various spectroscopic properties. Raman analysis has been carried out in order to know the vibrational groups present in the glass matrix. The optical band gap and Urbach energies have been evaluated from the absorption edges of the absorption spectra of 1.0 mol% Sm2O3 doped fluorosilicate glass. The Judd-Ofelt (JO) analysis has been applied to evaluate the intensity parameters, Ωλ (λ=2,4 and 6), for 1.0 mol% Sm2O3 doped fluorosilicate glass. These JO parameters have been used to evaluate radiative properties such as radiative transition probabilities, branching ratios, radiative lifetime and stimulated emission cross-sections for the luminescent levels of Sm3+ ion. The decay curve analysis has been performed for all the glasses in order to know the energy transfer processes between Sm3+ ions. The results indicate that the present glasses could be useful for photonics applications.

  15. Effect of mixed transition metal ions on DC conductivity in lithium bismuth borate glasses

    SciTech Connect

    Khasa, S.; Yadav, Arti Dahiya, M. S.; Seema,; Ashima; Agarwal, A.

    2015-06-24

    The DC conductivities of glasses having composition x(2NiO·V{sub 2}O{sub 5})·(30-x)Li{sub 2}O·20Bi{sub 2}O{sub 3}·50B{sub 2}O{sub 3} (with x=0, 2, 5, 7 and 10, i.e. NVLBB glasses) and glass samples having composition 7NiO·23 Li{sub 2}O·20Bi{sub 2}O{sub 3}·50B{sub 2}O{sub 3} and 7V{sub 2}O{sub 5}·23Li{sub 2}O·20Bi{sub 2}O{sub 3}·50B{sub 2}O{sub 3} (NLBB and VLBB respectively) are investigated as a function of temperature. Conductivity for glasses containing higher percentage of lithium ions is predominantly ionic and in glasses containing higher percentage of transition metal (TM) ions is predominantly electronic. The observed increase in conductivity with x and peak-like behavior at x=7 in NVLBB glasses due to competitive transport of small polaron contributing to a significant structural change in NVLBB glasses. Variation of molar volume and density was also observed with x. In NVLBB glasses, as x increases density increases except a slight decrease at x=7. Also density increases in NLBB whereas in case of VLBB it decreases in comparison to NVLBB1 glass composition. Mott’s small polaron hopping (SPH) model has been applied to analyze the high temperature conductivity data and activation energy.

  16. Radioluminescence properties of Sm-doped fluorochlorozirconate glasses and glass-ceramics

    NASA Astrophysics Data System (ADS)

    Okada, Go; Edgar, Andy; Kasap, Safa; Yanagida, Takayuki

    2016-02-01

    We have investigated X-ray induced radioluminescence (XL) properties of Sm-doped fluorochlorozirconate (FCZ) glasses and glass-ceramics. The FCZ glass is a modified ZBLAN glass which shows a very high optical transmission over a wide spectral range. The glass matrix includes Sm3+-doped nanocrystals of BaCl2 after heat-treatment at temperatures above 250 °C. The glass-ceramic emits red light under UV and X-ray exposure. Since conventional Si-based photodetectors, e.g., CCDs, have the highest quantum efficiency to red light in general, the Sm-doped FCZ glass-ceramic plate can be a good candidate as a scintillator material for indirect radiation detection. Moreover, a very broad emission is present in the glass-ceramic around 300-500 nm, which is attributed to a self-trapped exciton (STE) emissions. The temperature dependence of X-ray induced luminescence and photoluminescence are very similar. The XL light yield is linearly proportional to the X-ray exposure rate for rates higher than 20 mR/s. For low exposure rates, emissions by Sm2+ are more sensitive than others, leading to a nonlinear response.

  17. Effect of alkali addition on DC conductivity and thermal properties of vanadium-bismo-borate glasses

    SciTech Connect

    Khasa, S. Dahiya, M. S.; Agarwal, A.

    2014-04-24

    The DC Conductivity and Differential Thermal Analysis of glasses with composition (30−x)Li{sub 2}O⋅xV{sub 2}O{sub 5}⋅20Bi{sub 2}O{sub 3}⋅50B{sub 2}O{sub 3}(x=15, 10, 5) has been carried out in order to study the effect of replacing the Transition Metal Oxide (TMO) with alkali oxide. A significant increase in the DC conductivity has been observed with increase in alkali content. Again the thermal measurements have shown the decrease in both glass transition temperature (T{sub g}) and crystallization temperature (T{sub x}). The Glass Stability (GS) and Glass Forming Ability (GFA) have also been calculated and these also were found to decrease with increase in alkali oxide content at the cost of TMO.

  18. Magnetic nanoparticles formed in glasses co-doped with iron and larger radius elements

    SciTech Connect

    Edelman, I.; Ivanova, O.; Ivantsov, R.; Velikanov, D.; Zabluda, V.; Zubavichus, Y.; Veligzhanin, A.; Zaikovskiy, V.; Stepanov, S.; Artemenko, A.; Curely, J.; Kliava, J.

    2012-10-15

    A new type of nanoparticle-containing glasses based on borate glasses co-doped with low contents of iron and larger radius elements, Dy, Tb, Gd, Ho, Er, Y, and Bi, is studied. Heat treatment of these glasses results in formation of magnetic nanoparticles, radically changing their physical properties. Transmission electron microscopy and synchrotron radiation-based techniques: x-ray diffraction, extended x-ray absorption fine structure, x-ray absorption near-edge structure, and small-angle x-ray scattering, show a broad distribution of nanoparticle sizes with characteristics depending on the treatment regime; a crystalline structure of these nanoparticles is detected in heat treated samples. Magnetic circular dichroism (MCD) studies of samples subjected to heat treatment as well as of maghemite, magnetite, and iron garnet allow to unambiguously assign the nanoparticle structure to maghemite, independently of co-dopant nature and of heat treatment regime used. Different features observed in the MCD spectra are related to different electron transitions in Fe{sup 3+} ions gathered in the nanoparticles. The static magnetization in heat treated samples has non-linear dependence on the magnetizing field with hysteresis. Zero-field cooled magnetization curves show that at higher temperatures the nanoparticles occur in superparamagnetic state with blocking temperatures above 100 K. Below ca. 20 K, a considerable contribution to both zero field-cooled and field-cooled magnetizations occurs from diluted paramagnetic ions. Variable-temperature electron magnetic resonance (EMR) studies unambiguously show that in as-prepared glasses paramagnetic ions are in diluted state and confirm the formation of magnetic nanoparticles already at earlier stages of heat treatment. Computer simulations of the EMR spectra corroborate the broad distribution of nanoparticle sizes found by 'direct' techniques as well as superparamagnetic nanoparticle behaviour demonstrated in the magnetization

  19. Structural and spectroscopic behavior of Er3+:Yb3+ co-doped lithium telluroborate glasses

    NASA Astrophysics Data System (ADS)

    Annapoorani, K.; Maheshvaran, K.; ArunKumar, S.; Suriya Murthy, N.; Soukka, Tero; Marimuthu, K.

    2015-01-01

    A new series of Er3+:Yb3+ co-doped Lithium telluroborate glasses were prepared following the melt quenching technique. The structural analyzes were made through XRD, Raman, FTIR spectra to explore the different vibrations of borate and tellurite network. The absorption spectra have been used to determine the nature of the metal-ligand and further Band gap and Urbach's analysis have also been carried out. The oscillator strength value of the 2H11/2→4I15/2 hypersensitive transition is found to be higher and increases as the concentration of the RE ion increases which emphasis the asymmetry nature of the glasses. The magnitude of the JO intensity parameters follow the trend as Ω2>Ω4>Ω6 uniformly for all the prepared glasses. A bright green emission corresponding to the 2H11/2+4S3/2→ 4I15/2 transition and luminescence from 4I13/2→4I15/2 in eye safe region have also been observed. The radiative parameters such as radiative transition probability, stimulated emission cross-section, branching ratios, radiative lifetime, gain bandwidth and gain linewidth for the 4S3/2 and 4I13/2 level of the title glasses have also been determined. The absorption and emission cross-section corresponding to the 4I13/2 level has been calculated using McCumber theory. Lifetime measurements were made under 980 nm excitation and the quantum efficiency were also calculated to evaluate the appropriateness of the host matrix for the fabrication of laser materials and broad band amplifiers.

  20. Magnetic nanoparticles formed in glasses co-doped with iron and larger radius elements

    NASA Astrophysics Data System (ADS)

    Edelman, I.; Ivanova, O.; Ivantsov, R.; Velikanov, D.; Zabluda, V.; Zubavichus, Y.; Veligzhanin, A.; Zaikovskiy, V.; Stepanov, S.; Artemenko, A.; Curély, J.; Kliava, J.

    2012-10-01

    A new type of nanoparticle-containing glasses based on borate glasses co-doped with low contents of iron and larger radius elements, Dy, Tb, Gd, Ho, Er, Y, and Bi, is studied. Heat treatment of these glasses results in formation of magnetic nanoparticles, radically changing their physical properties. Transmission electron microscopy and synchrotron radiation-based techniques: x-ray diffraction, extended x-ray absorption fine structure, x-ray absorption near-edge structure, and small-angle x-ray scattering, show a broad distribution of nanoparticle sizes with characteristics depending on the treatment regime; a crystalline structure of these nanoparticles is detected in heat treated samples. Magnetic circular dichroism (MCD) studies of samples subjected to heat treatment as well as of maghemite, magnetite, and iron garnet allow to unambiguously assign the nanoparticle structure to maghemite, independently of co-dopant nature and of heat treatment regime used. Different features observed in the MCD spectra are related to different electron transitions in Fe3+ ions gathered in the nanoparticles. The static magnetization in heat treated samples has non-linear dependence on the magnetizing field with hysteresis. Zero-field cooled magnetization curves show that at higher temperatures the nanoparticles occur in superparamagnetic state with blocking temperatures above 100 K. Below ca. 20 K, a considerable contribution to both zero field-cooled and field-cooled magnetizations occurs from diluted paramagnetic ions. Variable-temperature electron magnetic resonance (EMR) studies unambiguously show that in as-prepared glasses paramagnetic ions are in diluted state and confirm the formation of magnetic nanoparticles already at earlier stages of heat treatment. Computer simulations of the EMR spectra corroborate the broad distribution of nanoparticle sizes found by "direct" techniques as well as superparamagnetic nanoparticle behaviour demonstrated in the magnetization studies.

  1. Bioactive borate glass promotes the repair of radius segmental bone defects by enhancing the osteogenic differentiation of BMSCs.

    PubMed

    Zhang, Jieyuan; Guan, Junjie; Zhang, Changqing; Wang, Hui; Huang, Wenhai; Guo, Shangchun; Niu, Xin; Xie, Zongping; Wang, Yang

    2015-12-01

    Bioactive borate glass (BG) has emerged as a promising alternative for bone regeneration due to its high osteoinductivity, osteoconductivity, compressive strength, and biocompatibility. However, the role of BG in large segmental bone repair is unclear and little is known about the underlying mechanism of BG's osteoinductivity. In this study, we demonstrated that BG possessed pro-osteogenic effects in an experimental model of critical-sized radius defects. Transplanting BG to radius defects resulted in better repair of bone defects as compared to widely used β-TCP. Histological and morphological analysis indicated that BG significantly enhanced new bone formation. Furthermore, the degradation rate of the BG was faster than that of β-TCP, which matched the higher bone regeneration rate. In addition, ions from BG enhanced cell viability, ALP activity, and osteogenic-related genes expression. Mechanistically, the critical genes Smad1/5 and Dlx5 in the BMP pathway and p-Smad1/5 proteins were significantly elevated after BG transplantation, and these effects could be blocked by the BMP/Smad specific inhibitor. Taken together, our findings suggest that BG could repair large segmental bone defects through activating the BMP/Smad pathway and osteogenic differentiation in BMSCs. PMID:26586668

  2. Origin of broad NIR photoluminescence in bismuthate glass and Bi-doped glasses at room temperature.

    PubMed

    Peng, Mingying; Zollfrank, Cordt; Wondraczek, Lothar

    2009-07-15

    Bi-doped glasses with broadband photoluminescence in the near-infrared (NIR) spectral range are presently receiving significant consideration for potential applications in telecommunications, widely tunable fiber lasers and spectral converters. However, the origin of NIR emission remains disputed. Here, we report on NIR absorption and emission properties of bismuthate glass and their dependence on the melting temperature. Results clarify that NIR emission occurs from the same centers as it does in Bi-doped glasses. The dependence of absorption and NIR emission of bismuthate glasses on the melting temperature is interpreted as thermal dissociation of Bi(2)O(3) into elementary Bi. Darkening of bismuthate glass melted at 1300 °C is due to the agglomeration of Bi atoms. The presence of Bi nanoparticles is confirmed by transmission electron microscopy, high-resolution energy dispersive x-ray spectroscopy and element distribution mapping. By adding antimony oxide as an oxidation agent to the glass, NIR emission centers can be eliminated and Bi(3+) is formed. By comparing with atomic spectral data, absorption bands at ∼320 , ∼500 , 700 , 800 and 1000 nm observed in Bi-doped glasses are assigned to Bi(0) transitions [Formula: see text], [Formula: see text], [Formula: see text], [Formula: see text] and [Formula: see text], respectively, and broadband NIR emission is assigned to the transition [Formula: see text].

  3. Photosensitivity of Ge-doped phosphate glass to 244 nm irradiation

    SciTech Connect

    Suzuki, S.; Schuelzgen, A.; Sabet, S.; Moloney, J. V.; Peyghambarian, N.

    2006-10-23

    UV photosensitivity of Ge-doped phosphate glasses is examined by writing photoinduced gratings in bulk glass samples. Radiation-induced index changes up to {approx}3.5x10{sup -5} were obtained by diffraction efficiency measurements of UV written gratings. In contrast to phosphate glasses without intentional doping, no significant photodarkening at visible wavelength was observed in Ge-doped phosphate glasses after UV exposure. The measured index changes demonstrate the potential of Ge-doped phosphate glasses for the fabrication of a fiber Bragg grating, a key component for phosphate-glass-based photonic devices.

  4. Effect of substituting iron on structural, thermal and dielectric properties of lithium borate glasses

    SciTech Connect

    Dalal, Seema; Khasa, S.; Dahiya, M.S.; Agarwal, A.; Yadav, Arti; Seth, V.P.; Dahiya, S.

    2015-10-15

    Highlights: • There is increase in NBOs with iron content. • FTIR spectra supported the results predicted by density. • Glass stability has been examined. • Iron shows “blocking effect” on migration of mobile ions. • Internal Circuit varies with temperature and composition. - Abstract: Glasses with composition xFe{sub 2}O{sub 3}·(30 − x)Li{sub 2}O·70B{sub 2}O{sub 3} (x = 0, 2, 5, 7 and 10 mol%) were prepared via melt-quenching technique and their physical, thermal and dielectric properties are discussed. XRD was carried out to confirm the amorphous nature of prepared glasses. Density (ρ) and molar volume (V{sub m}) were found to increase with increase in Fe{sub 2}O{sub 3} content. Infrared absorption spectra depicted that Fe{sub 2}O{sub 3} is acting as a network modifier. DTA has been carried out to determine glass transition temperature (T{sub g}) and crystallization temperature (T{sub x}). Electrical properties have been studied using impedance spectroscopy and dc conductivity. The dc conductivity decreases and activation energy increases on replacing Li{sup +} ions with Fe{sup 3+}. The impedance measurements reveal that the total conductivity obeys Jonscher’s power law. Study of the equivalent circuit analysis up to a temperature of 523 K shows a significant change in the equivalent circuitry with change in temperature and composition.

  5. Ytterbium-doped glass-ceramics for optical refrigeration.

    PubMed

    Filho, Elton Soares de Lima; Krishnaiah, Kummara Venkata; Ledemi, Yannick; Yu, Ye-Jin; Messaddeq, Younes; Nemova, Galina; Kashyap, Raman

    2015-02-23

    We report for the first time the characterization of glass-ceramics for optical refrigeration. Ytterbium-doped nanocrystallites were grown in an oxyfluoride glass matrix of composition 2YbF(3):30SiO(2)-15Al(2)O(3)-25CdF(2)-22PbF(2)-4YF(3), forming bulk glass-ceramics at three different crystalisation levels. The samples are compared with a corresponding uncrystalised (glass) sample, as well as a Yb:YAG sample which has presented optical cooling. The measured X-ray diffraction spectra, and thermal capacities of the samples are reported. We also report for the first time the use of Yb:YAG as a reference for absolute photometric quantum efficiency measurement, and use the same setup to characterize the glass and glass-ceramic samples. The cooling figure-of-merit was measured by optical calorimetry using a fiber Bragg grating and found to depend on the level of crystallization of the sample, and that samples with nanocrystallites result in higher quantum efficiency and lower background absorption than the pure-glass sample. In addition to laser-induced cooling, the glass-ceramics have the potential to serve as a reference for quantum efficiency measurements. PMID:25836500

  6. EPR and impedance spectroscopic investigations on lithium bismuth borate glasses containing nickel and vanadium ions

    NASA Astrophysics Data System (ADS)

    Yadav, Arti; Khasa, Satish; Hooda, Ashima; Dahiya, Manjeet S.; Agarwal, Ashish; Chand, Prem

    2016-03-01

    Glasses having composition 7NiO • 23Li2O • 20Bi2O3 • 50B2O3, 7V2O5 • 23Li2O • 20Bi2O3 • 50B2O3 and x(2NiO • V2O5) • (30 - x)Li2O • 50B2O3 • 20Bi2O3 (with x = 0, 2, 5, 7 & 10 mol%) prepared through melt-quench route are explored by analyzing density, impedance spectroscopy and electron paramagnetic resonance (EPR). It is found that both density and molar volume increase with an increase in substitution of 2NiO • V2O5 in the base glass matrix. Different dielectric parameters viz. dielectric loss (ε), electrical modulus (M), loss tangent (tanδ) etc. are evaluated and their variations with frequency and temperature are analyzed which reveals that these glasses exhibit a non-Debye relaxation behavior. A phenomenal description of the capacitive behavior is obtained by considering the circuitry as a parallel combination of bulk resistance (Rb) and constant phase element (CPE). The conduction mechanism is found to follow Quantum Mechanical Tunneling (QMT) model. Spin Hamiltonian Parameters (SHPs) and covalency rates are calculated from the EPR spectra of vanadyl ion. The observed EPR spectra confirmed that V4 + ion exists as vanadyl ion in the octahedral coordination with tetragonal compression.

  7. Magnetic properties of nonirradiated and neutron irradiated iron-lead-borate glasses

    SciTech Connect

    Burzo, E.; Ursu, I.; Ungur, D.; Ardelean, I.; Nazarov, V.M.

    1985-11-01

    The results of magnetic measurements performed on xFe/sub 2/O/sub 3/(1-x)(yB/sub 2/O/sub 3/ PbO) glasses having y = 0.5, 1, 2, and 3 and x< or =25 mol % Fe/sub 2/O/sub 3/ are reported. For identical Fe/sub 2/O/sub 3/ content the Curie constants are greater as the PbO content of the glass matrix is higher. This is due to the increase of the fraction of Fe/sup 3 +/ ions as evidenced by Moessbauer effect measurements. As B/sub 2/O/sub 3/ content increases, a more random distribution of the ferric ions in the glass matrix takes place. Under the action of fast neutrons some iron ions situated in clusters are displaced and occupy sites more randomly distributed in the B/sub 2/O/sub 3/-PbO matrix. In addition, a fraction of ferrous ions is converted to ferric.

  8. XRD and FTIR structural investigation of gadolinium-zinc-borate glass ceramics

    SciTech Connect

    Borodi, G.; Pascuta, P.; Dan, V.; Pop, V.; Stefan, R.; Radulescu, D.

    2013-11-13

    X-ray diffraction (XRD) and Fourier transform infrared (FTIR) spectroscopy measurements have been employed to investigate the (Gd{sub 2}O{sub 3}){sub x}⋅(B{sub 2}O{sub 3}){sub (60−x)}⋅(ZnO){sub 40} glass ceramics system, with 0 ≤ x ≤ 15 mol%. After heat treatment applied at 860 °C for 2 h, some structural changes were observed and new crystalline phases appeared in the structure of the samples. In these glass ceramics four crystalline phases were identified using powder diffraction files (PDF 2), namely ZnB{sub 4}O{sub 7}, Zn{sub 4}O(B{sub 6}O{sub 12}), Zn{sub 3}(BO{sub 3}){sub 2} and GdBO{sub 3}. From the XRD data, the average unit-cell parameter and the quantitative ratio of the crystallographic phases in the studied samples were evaluated. FTIR data revealed that the BO{sub 3}, BO{sub 4} and ZnO{sub 4} are the main structural units of these glass ceramics network. The compositional dependence of the different structural units which appear in the studied samples was followed.

  9. EPR and impedance spectroscopic investigations on lithium bismuth borate glasses containing nickel and vanadium ions.

    PubMed

    Yadav, Arti; Khasa, Satish; Hooda, Ashima; Dahiya, Manjeet S; Agarwal, Ashish; Chand, Prem

    2016-03-15

    Glasses having composition 7NiO∙23Li2O∙20Bi2O3∙50B2O3, 7V2O5∙23Li2O∙20Bi2O3∙50B2O3 and x(2NiO∙V2O5)∙(30-x)Li2O∙50B2O3∙20Bi2O3 (with x=0, 2, 5, 7 & 10 mol%) prepared through melt-quench route are explored by analyzing density, impedance spectroscopy and electron paramagnetic resonance (EPR). It is found that both density and molar volume increase with an increase in substitution of 2NiO∙V2O5 in the base glass matrix. Different dielectric parameters viz. dielectric loss (ε), electrical modulus (M), loss tangent (tanδ) etc. are evaluated and their variations with frequency and temperature are analyzed which reveals that these glasses exhibit a non-Debye relaxation behavior. A phenomenal description of the capacitive behavior is obtained by considering the circuitry as a parallel combination of bulk resistance (Rb) and constant phase element (CPE). The conduction mechanism is found to follow Quantum Mechanical Tunneling (QMT) model. Spin Hamiltonian Parameters (SHPs) and covalency rates are calculated from the EPR spectra of vanadyl ion. The observed EPR spectra confirmed that V(4+) ion exists as vanadyl ion in the octahedral coordination with tetragonal compression.

  10. Bismuth-doped Mg - Al silicate glasses and fibres

    SciTech Connect

    Bufetov, Igor' A; Vel'miskin, V V; Galagan, B I; Denker, B I; Sverchkov, S E; Semjonov, S L; Firstov, Sergei V; Shulman, I L; Dianov, Evgenii M

    2012-09-30

    This paper compares the optical properties of bulk bismuth-doped Mg - Al silicate glasses prepared in an iridium crucible to those of optical fibres prepared by the powder-in-tube method and having a core identical in composition to the glasses. The bulk glasses and fibres are shown to be similar in luminescence properties. The optical loss in the fibres in their IR luminescence band is about one order of magnitude lower than that in the crucible-melted glasses. The level of losses in the fibres and their luminescence properties suggest that such fibres can be made to lase near 1.15 {mu}m. (optical fibres, lasers and amplifiers. properties and applications)

  11. Silver doped nanobioactive glass particles for bone implant applications

    SciTech Connect

    Prabhu, M.; Kavitha, K.; Karunakaran, G.; Manivasakan, P.; Rajendran, V.

    2013-02-05

    Silica based silver doped nanobioactive glass compositions (58SiO{sub 2}-33CaO-9P{sub 2}O{sub 5} and 58SiO{sub 2}-23CaO-9P{sub 2}O{sub 5}-10Ag{sub 2}O(mol%)) were synthesized by a simple sol-gel route. The prepared samples were comprehensively characterised by X-ray diffraction, Fourier transform infrared spectroscopy, transmission electron microscopy and scanning electron microscopic studies. The results reveal that the prepared samples have amorphous phase with spherical morphology and having a particle size less than 100 nm. The specific surface areas were 90 and 61 m{sup 2}g{sup -1} respectively. The in vitro bioactivity of glass samples were confirmed by the formation of hydroxyapatite layer on glass surfaces. The Ag{sub 2}O-doped nanobioactive glasse samples shows reveal significant antibacterial activity compare with base glasses.

  12. Upconversion in erbium-doped transparent glass ceramics

    NASA Astrophysics Data System (ADS)

    Jones, Gina Christine

    2005-11-01

    Transparent glass ceramics (TGCs) are a class of materials that are composed of a robust glass matrix which is densely embedded with nanometer-sized fluoride crystals: In bulk, fluoride materials tend to have poor handling and mechanical properties, and can be expensive to produce. In contrast, the forming and handling properties of the TGC are similar to those of the precursor, glass, and are engineered to be robust and mechanically stable. Rare earth ions can be incorporated into the TGC during manufacture and can become partially segregated into the crystalline phase. There they experience the low-phonon energy environment of the fluoride nanocrystallite, which induces long energy level lifetimes and enhanced frequency upconversion. Therefore, rare earth doped TGCs can have the spectroscopic properties of a crystal with the durability of an aluminosilicate glass. Upconversion fluorescence is studied for an aluminosilicate TGC containing LaF3 nanocrystallites and doped with an erbium density of 1.7 x 1020 CM-3. Time gated fluorescence and excitation spectra as well as photoluminescence decays are used to find the nature and origin of this fluorescence. It is determined that energy transfer upconversion occurs only in the nanocrystallite phase and sequential two-photon absorption upconversion occurs in both glass and crystal phases.

  13. Ab Initio Molecular Dynamics Simulations and GIPAW NMR Calculations of a Lithium Borate Glass Melt.

    PubMed

    Ohkubo, Takahiro; Tsuchida, Eiji; Takahashi, Takafumi; Iwadate, Yasuhiko

    2016-04-14

    The atomic structure of a molten 0.3Li2O-0.7B2O3 glass at 1250 K was investigated using ab initio molecular dynamics (AIMD) simulations. The gauge including projector augmented wave (GIPAW) method was then employed for computing the chemical shift and quadrupolar coupling constant of (11)B, (17)O, and (7)Li from 764 AIMD derived structures. The chemical shift and quadrupolar coupling constant distributions were directly estimated from the dynamical structure of the molten glass. (11)B NMR parameters of well-known structural units such as the three-coordinated ring, nonring, and four-coordinated tetrahedron were found to be in good agreement with the experimental results. In this study, more detailed classification of B units was presented based on the number of O species bonded to the B atoms. This highlights the limitations of (11)B NMR sensitivity for resolving (11)B local environment using the experimentally obtained spectra only. The (17)O NMR parameter distributions can theoretically resolve the bridging and nonbridging O atoms with different structural units such as nonring, single boroxol ring, and double boroxol ring. Slight but clear differences in the number of bridging O atoms surrounding Li that have not been reported experimentally were observed in the theoretically obtained (7)Li NMR parameters. PMID:27010637

  14. Spectral investigations on Dy{sup 3+}-doped transparent oxyfluoride glasses and nanocrystalline glass ceramics

    SciTech Connect

    Babu, P.; Jang, Kyoung Hyuk; Kim, Eun Sik; Shi, Liang; Seo, Hyo Jin; Rivera-Lopez, F.; Rodriguez-Mendoza, U. R.; Lavin, V.; Vijaya, R.; Jayasankar, C. K.; Rama Moorthy, L.

    2009-01-01

    Dysprosium-doped oxyfluoride glasses and nanocrystalline glass ceramics have been synthesized and studied by x-ray diffraction, absorption, and visible and near-infrared emission spectra. The samples emit intense white light when populating the {sup 4}F{sub 9/2} level with a 451 nm laser light and, from the visible emission spectra, yellow to blue intensity ratios and chromaticity color coordinates have been calculated and their relative variation have been discussed based on the concentration of Dy{sup 3+} ions and the heat treatment conditions used to prepare the glass ceramics. Infrared emission has also been observed in glasses and glass ceramics after laser excitation at 800 nm, showing bands at 1.33 and 1.67 {mu}m, useful for optical amplification in fiber amplifiers.

  15. Are Magnetically Doped Transition-metal Oxides Spin-glasses?

    NASA Astrophysics Data System (ADS)

    Lussier, A.; Dvorak, J.; Idzerda, Y. U.; Ogale, S. B.; Shinde, S. R.; Venkatesan, T.; Lofland, S. E.

    2004-03-01

    Many magnetic impurity doped transition-metal oxides exhibit ferromagnetism at room temperature. Some also exhibit strange magnetic aging behavior. One such material is Co-doped SnO2 which displays a saturation magnetization decrease over time, as well as with successive field applications. From the theoretical perspective, there are two prerequisites for spin-glass behavior which are both satisfied for these samples: disorder and frustration. Disorder is readily satisfied because the dilute magnetic impurities are randomly scattered. Additionally, the suggested RKKY interaction between magnetic impurities, coupled with their random spacing, likely results in frustration. Magnetometry, XAS, and XMCD measurements, with temperature, measurement time, and history dependence help elucidate the magnetic order in these materials, and are consistent with spin-glass character. We would like to acknowledge the support of NSF (MSU), the Office of Naval Research (MSU), DARPA SpinS (UMD) and NSF-MRSEC (UMD).

  16. Luminescence properties of Cr-doped silica sol gel glasses

    NASA Astrophysics Data System (ADS)

    Strek, Wieslaw; Lukowiak, Edward; Deren, Przemyslaw J.; Maruszewski, K.; Trabjerg, Ib; Koepke, Czeslaw; Malashkevich, G. E.; Gaishun, Vladimir E.

    1997-11-01

    The emission of Cr-doped silica glass obtained by the sol- gel method is characterized by an orange broad band with a maximum at 610 nm. Its nature is examined by the absorption, excited state absorption, emission, excitation and lifetime measurements over a wide range of temperature and for different concentration of Cr ions. Our measurement show that in spite of fact that the absorption properties of Cr- doped silica sol-gel glass are predominantly associated with Cr4+ centers, the observed in visible range emission can be assigned neither to Cr3+ nor to Cr4+ ions. The discussion of the nature of observed emission was carried out for all possible valencies of the Cr ions. In conclusion is suggested that it may be ascribed to the transitions on the monovalent Cr1+ ion. The reducing agents occurring during the sol-gel process and leading to lowering the Cr valency are discussed.

  17. Excited state cross sections for Er-doped glasses

    NASA Astrophysics Data System (ADS)

    Zemon, Stanley A.; Lambert, Gary M.; Miniscalco, William J.; Davies, Richard W.; Hall, Bruce T.; Folweiler, Robert C.; Wei, Ta-Sheng; Andrews, Leonard J.; Singh, Mahendra P.

    1991-01-01

    Excited-state-absorption (ESA) cross sections were determined for the region between 760 and 900 nm for Er-doped fluorophosphate phosphate and silicate glasses. Measurements were performed on multimode fibers pumping at 647 nm with powers 1 . 5 Wto invert the population into the saturation regime. Over much of the 800-nm band ground-state-absorption (GSA) cross sections are equal to or greater than ESA cross sections. For comparison ESA was also measured for singlemode Al/P-doped silica fiber. The cross sections were incorporated into an amplifier model and the phosphate and fluorophosphate glasses were found to provide higher gain than silica for pumping in the 800-nm band. Photoexcited fluorozirconates were found to have substantial populations in the first four excited states and ESA transitions originating from these states are identified.

  18. Bose glass and Mott glass of quasiparticles in a doped quantum magnet.

    PubMed

    Yu, Rong; Yin, Liang; Sullivan, Neil S; Xia, J S; Huan, Chao; Paduan-Filho, Armando; Oliveira, Nei F; Haas, Stephan; Steppke, Alexander; Miclea, Corneliu F; Weickert, Franziska; Movshovich, Roman; Mun, Eun-Deok; Scott, Brian L; Zapf, Vivien S; Roscilde, Tommaso

    2012-09-20

    The low-temperature states of bosonic fluids exhibit fundamental quantum effects at the macroscopic scale: the best-known examples are Bose-Einstein condensation and superfluidity, which have been tested experimentally in a variety of different systems. When bosons interact, disorder can destroy condensation, leading to a 'Bose glass'. This phase has been very elusive in experiments owing to the absence of any broken symmetry and to the simultaneous absence of a finite energy gap in the spectrum. Here we report the observation of a Bose glass of field-induced magnetic quasiparticles in a doped quantum magnet (bromine-doped dichloro-tetrakis-thiourea-nickel, DTN). The physics of DTN in a magnetic field is equivalent to that of a lattice gas of bosons in the grand canonical ensemble; bromine doping introduces disorder into the hopping and interaction strength of the bosons, leading to their localization into a Bose glass down to zero field, where it becomes an incompressible Mott glass. The transition from the Bose glass (corresponding to a gapless spin liquid) to the Bose-Einstein condensate (corresponding to a magnetically ordered phase) is marked by a universal exponent that governs the scaling of the critical temperature with the applied field, in excellent agreement with theoretical predictions. Our study represents a quantitative experimental account of the universal features of disordered bosons in the grand canonical ensemble.

  19. Mid-IR and far-IR investigation of AgI-doped silver diborate glasses

    SciTech Connect

    Hudgens, J.J.; Martin, S.W.

    1996-03-01

    The structures of {ital x}AgI+(1{minus}{ital x})Ag{sub 2}O{center_dot}2B{sub 2}O{sub 3} glasses, where 0.2{le}{ital x}{le}0.6, have been investigated using mid- and far-infrared spectroscopy. The mid-IR spectra revealed that in those glasses prepared using AgNO{sub 3} as the starting material for Ag{sub 2}O, the BO{sub 4}{sup {minus}}/BO{sub 3} ratio is constant with increasing amounts of AgI as would be expected form the proposed behavior of AgI in these glasses. However, a survey of the literature revealed those glasses prepared from pure Ag{sub 2}O show a strong linear dependence of the BO{sub 4}{sup {minus}}/BO{sub 3} ratio on AgI content. Most probably, in those glasses prepared with Ag{sub 2}O the Ag{sub 2}O/B{sub 2}O{sub 3} ratio changes with AgI content due to the decomposition of Ag{sub 2}O during melting. This different behavior is associated with AgNO{sub 3} decomposing to Ag{sub 2}O with heating followed by incorporation into the glassy network. For Ag{sub 2}O used directly, it is proposed that it decomposes to Ag metal and O{sub 2}(gas) with heating before it can be incorporated into the borate network. This latter behavior decreases with increasing AgI in the batch composition because AgI lowers the liquidus temperature of the melt considerably. The far-IR analysis of the AgI-doped silver diborate glasses suggests that there are three coordination environments for the Ag{sup +} ions; one with iodide anions and the other two with oxygen ions. It is proposed that the separate oxygen coordination environments for the Ag{sup +} ions arise from one with bridging oxygens of BO{sub 4}{sup {minus}} units, and the other with nonbridging oxygens on BO{sub 3}{sup {minus}} units. Furthermore, it is proposed that the Ag{sup +} ions in the iodide-ion environments progressively agglomerate into disordered regions of AgI, but do not form structures similar to {alpha}-AgI. (Abstract Truncated)

  20. AC Conductivity Studies in Lithium-Borate Glass Containing Gold Nanoparticles

    NASA Astrophysics Data System (ADS)

    Shivaprakash, Y.; Anavekar, R. V.

    2011-07-01

    Gold nanoparticles have been synthesized in a base glass with composition 30Li2O-70B2O3 using gold chloride (HAuCl4.3H2O) as a dopant. The samples are characterized using XRD, ESR, SEM and optical absorption in the visible range. AC conductivity studies have been performed at RT over a frequency range 100 to 10 MHz. The dc conductivity is calculated from the complex impedence plot. The dc conductivity is found to be increasing with the increase of dopant concentration. AC conductivity data is fitted with Almond-West law with power exponent `s'. The values of `s' is found to lie in the range of 0.70-0.73.

  1. Luminescence characteristics of Li₂CO₃-K₂CO₃-H₃BO₃ glasses co-doped with TiO₂/MgO.

    PubMed

    Alajerami, Yasser Saleh Mustafa; Hashim, Suhairul; Ghoshal, Sib Krishna; Ramli, Ahmad Termizi; Saleh, Muneer Aziz; Ibrahim, Zuhairi; Kadni, Taiman; Bradley, David Andrew

    2013-12-01

    Understanding the influence of co-dopants in the luminescence enhancement of carbonate glasses is the key issue in dosimetry. A series of borate glasses modified by lithium and potassium carbonate were synthesized by the melt-quenching method. The glass mixture activated with various concentrations of TiO2 and MgO was subjected to various doses of gamma-rays ((60)Co). The amorphous nature of the samples was confirmed by x-ray diffraction (XRD) spectra. The simple glowing curve of the glass doped with TiO2 features a peak at 230°C, whose intensity is maximal at 0.5 mol% of the dopant. The intensity of the glowing curve increases with the concentration of MgO added as a co-dopant up to 0.25 mol%, where it is two times higher than for the material without MgO thermoluminescence properties, including dose response, reproducibility, and fading were studied. The effective atomic number of the material was also determined. Kinetic parameters, such as kinetics order, activation energy, and frequency factor are estimated. The photoluminescence spectra of the titanium-doped glass consist of a prominent peaks at 480 nm when laser excitation at 650 nm is used. A three-fold photoluminescence enhancement and a blue shift of the peak were observed when 0.1% MgO was introduced. In addition, various physical parameters, such as ion concentration, polaron radius and internuclear distances were calculated. The mechanism for the thermoluminescence and photoluminescence enhancements are discussed. PMID:23948307

  2. Ytterbium-doped all glass leakage channel fibers with highly fluorine-doped silica pump cladding.

    PubMed

    Dong, Liang; McKay, Hugh A; Fu, Libin; Ohta, Michiharu; Marcinkevicius, Andrius; Suzuki, Shigeru; Fermann, Martin E

    2009-05-25

    All glass leakage channel fibers have been demonstrated to be a potential practical solution for power scaling in fiber lasers beyond the nonlinear limits in conventional large mode area fibers. The all glass nature with absence of any air holes is especially useful for allowing the fibers to be used and fabricated much like conventional fibers. Previously, double clad active all glass leakage channel fibers used low index polymer as a pump guide with the drawbacks of being less reliable at high pump powers and not being able to change fiber outer diameter independent of pump guide dimension. In this work, we demonstrate, for the first time, ytterbium-doped double clad all glass leakage channel fibers with highly fluorine-doped silica as pump cladding. The new all glass leakage channel fibers have no polymer in the pump path and have independent control of fiber outer diameters and pump cladding dimension, and, therefore, enable designs with smaller pump guide for high pump absorption and, at the same time, with large fiber diameters to minimize micro and macro bending effects, a much desired features for large core fibers where intermodal coupling can be an issue due to a much increased mode density. An ytterbium-doped double clad PM fiber with core diameter of 80 microm is also reported, which can be coiled in 76 cm diameter coils.

  3. Glass transition temperature and conductivity in Li2O and Na2O doped borophosphate glasses

    NASA Astrophysics Data System (ADS)

    Ashwajeet, J. S.; Sankarappa, T.; Ramanna, R.; Sujatha, T.; Awasthi, A. M.

    2015-08-01

    Two alkali doped Borophosphate glasses in the composition, (B2O3)0.2. (P2O5)0.3. (Na2O)(0.5-x). (Li2O)x, where x = 0.05 to 0.50 were prepared by standard melt quenching method at 1200K. Non-crystalline nature was confirmed by XRD studies. Room temperature density was measured by Archimedes principle. DC conductivity in the temperature range from 300K to 575K has been measured. Samples were DSC studied in the temperature range from 423K to 673K and glass transition temperature was determined. Glass transition temperature passed through minima for Li2O con.2centration between 0.25 and 0.30 mole fractions. Activation energy of conduction has been determined by analyzing temperature variation of conductivity determining Arrhenius law. Conductivity passed through minimum and activation passed through maximum for Li2O content from 0.25 to 0.30 mole fractions. Glass transition temperature passed through minimum for the same range of Li2O content. These results revealed mixed alkali effect taking place in these glasses. It is for the first time borophosphate glasses doped with Li2O and Na2O have been studied for density and dc conductivity and, the mixed alkali effect (MAE) has been observed.

  4. Spectroscopic properties of Nd3+ doped transparent oxyfluoride glass ceramics.

    PubMed

    Yu, Yunlong; Chen, Daqin; Ma, En; Wang, Yuansheng; Hu, Zhongjian

    2007-07-01

    In this paper, the spectroscopic properties of Nd(3+) doped transparent oxyfluoride glass ceramics containing LaF(3) nano-crystals were systematically studied. The formation and distribution of LaF(3) nano-crystals in the glass matrix were investigated by X-ray diffraction (XRD) and transmission electron microscopy (TEM). Based on Judd-Ofelt theory, the intensity parameters Omega(t) (t=2, 4, 6), spontaneous emission probability, radiative lifetime, radiative quantum efficiency, width of the emission line and stimulated emission cross-section of Nd(3+) were evaluated. Particularly, the effect of Nd(3+) doping level on them was discussed. With the increase of Nd(3+) concentration in the glass ceramic, the experimental luminescence lifetime, radiative quantum efficiency and stimulated emission cross-section vary from 353.4 micros, 78.3% and 1.86 x 10(-20)cm(2) to 214.7 micros, 39.9% and 1.52 x 10(-20)cm(2), respectively. The comparative study of Nd(3+) spectroscopic parameters in different hosts suggests that the investigated glass ceramic system is potentially applicable as laser materials for 1.06 microm emission.

  5. Origin of broad NIR photoluminescence in bismuthate glass and Bi-doped glasses at room temperature

    NASA Astrophysics Data System (ADS)

    Peng, Mingying; Zollfrank, Cordt; Wondraczek, Lothar

    2009-07-01

    Bi-doped glasses with broadband photoluminescence in the near-infrared (NIR) spectral range are presently receiving significant consideration for potential applications in telecommunications, widely tunable fiber lasers and spectral converters. However, the origin of NIR emission remains disputed. Here, we report on NIR absorption and emission properties of bismuthate glass and their dependence on the melting temperature. Results clarify that NIR emission occurs from the same centers as it does in Bi-doped glasses. The dependence of absorption and NIR emission of bismuthate glasses on the melting temperature is interpreted as thermal dissociation of Bi2O3 into elementary Bi. Darkening of bismuthate glass melted at 1300 °C is due to the agglomeration of Bi atoms. The presence of Bi nanoparticles is confirmed by transmission electron microscopy, high-resolution energy dispersive x-ray spectroscopy and element distribution mapping. By adding antimony oxide as an oxidation agent to the glass, NIR emission centers can be eliminated and Bi3+ is formed. By comparing with atomic spectral data, absorption bands at ~320 , ~500 , 700 , 800 and 1000 nm observed in Bi-doped glasses are assigned to Bi0 transitions {}^{4}\\mathrm {S_{3/2}} \\to {}^{2}\\mathrm {P_{3/2}} , {}^{4}\\mathrm {S_{3/2}}\\to {}^{2}\\mathrm {P_{1/2}} , {}^{4}\\mathrm {S_{3/2}}\\to {}^{2}\\mathrm {D_{5/2}} , {}^{4}\\mathrm {S_{3/2}}\\to {}^{2}\\mathrm {D_{3/2}}(2) and {}^{4}\\mathrm {S_{3/2}}\\to {}^{2}\\mathrm {D_{3/2 }}(1) , respectively, and broadband NIR emission is assigned to the transition {}^{2}\\mathrm {D_{3/2}(1)}\\to {}^{4}\\mathrm {S_{3/2}} .

  6. Temperature dependent electrical transport characteristics of BaTiO{sub 3} modified lithium borate glasses

    SciTech Connect

    Thakur, Vanita; Singh, Anupinder; Singh, Lakhwant; Awasthi, A. M.

    2015-08-15

    The glass samples with composition (70B{sub 2}O{sub 3}-29Li{sub 2}O-1Dy{sub 2}O{sub 3})-xBT; x = 0, 10 and 20 weight percent, have been prepared by conventional melt quench technique. The dielectric measurements as a function of temperature have been carried out on these samples in the frequency range 1 Hz-10 MHz. The dielectric relaxation characteristics of these samples have been studied by analyzing dielectric spectroscopy, dielectric loss, electric modulus formulation and electrical conductivity spectroscopy. It is found that the dielectric permittivity of the samples increases with an increase in the temperature and BT content. The frequency dependent ac conductivity has been analyzed using Jonscher’s universal power law whereas non exponential KWW function has been invoked to fit the experimental data of the imaginary part of the electric modulus. The values of the activation energy determined from the electric modulus and that from dc conductivity have been found to be quite close to each other suggesting that the same type of charge barriers are involved in the relaxation and the conduction mechanisms. The stretched exponent (β) and the power exponent (n) have been found to be temperature and composition dependent. The decrease in n with an increase in temperature further suggested that the ac conduction mechanism of the studied samples follows the correlated barrier hopping (CBH) model.

  7. Conversion of melt-derived microfibrous borate (13-93B3) and silicate (45S5) bioactive glass in a simulated body fluid.

    PubMed

    Liu, Xin; Rahaman, Mohamed N; Day, Delbert E

    2013-03-01

    Microfibrous bioactive glasses are showing a considerable capacity to heal soft tissue wounds, but little information is available on the mechanism of healing. In the present study, the conversion of microfibrous borate bioactive glass (diameter = 0.2-5 μm) with the composition designated 13-93B3 (5.5 Na2O, 11.1 K2O, 4.6 MgO, 18.5 CaO, 3.7 P2O5, 56.6 B2O3 wt%) was evaluated in vitro as a function of immersion time in a simulated body fluid (SBF) at 37 °C using structural and chemical techniques. Silicate 45S5glass microfibers (45 SiO2, 24.5 Na2O, 24.5 CaO, 6 P2O5 wt%) were also studied for comparison. Microfibrous 13-93B3 glass degraded almost completely and converted to a calcium phosphate material within 7-14 days in SBF, whereas >85 % of the silica remained in the 45S5 microfibers, forming a silica gel phase. An amorphous calcium phosphate (ACP) product that formed on the 13-93B3 microfibers crystallized at a slower rate to hydroxyapatite (HA) when compared to the ACP that formed on the 45S5 fibers. For immersion times >3 days, the 13-93B3 fibers released a higher concentration of Ca into the SBF than the 45S5 fibers. The fast and more complete degradation, slow crystallization of the ACP product, and higher concentration of dissolved Ca in SBF could contribute to the capacity of the microfibrous borate 13-93B3 glass to heal soft tissue wounds.

  8. Silicate, borosilicate, and borate bioactive glass scaffolds with controllable degradation rate for bone tissue engineering applications. II. In vitro and in vivo biological evaluation.

    PubMed

    Fu, Qiang; Rahaman, Mohamed N; Bal, B Sonny; Bonewald, Lynda F; Kuroki, Keiichi; Brown, Roger F

    2010-10-01

    In Part I, the in vitro degradation of bioactivAR52115e glass scaffolds with a microstructure similar to that of human trabecular bone, but with three different compositions, was investigated as a function of immersion time in a simulated body fluid. The glasses consisted of a silicate (13-93) composition, a borosilicate composition (designated 13-93B1), and a borate composition (13-93B3), in which one-third or all of the SiO2 content of 13-93 was replaced by B2O3, respectively. This work is an extension of Part I, to investigate the effect of the glass composition on the in vitro response of osteogenic MLO-A5 cells to these scaffolds, and on the ability of the scaffolds to support tissue infiltration in a rat subcutaneous implantation model. The results of assays for cell viability and alkaline phosphatase activity showed that the slower degrading silicate 13-93 and borosilicate 13-93B1 scaffolds were far better than the borate 13-93B3 scaffolds in supporting cell proliferation and function. However, all three groups of scaffolds showed the ability to support tissue infiltration in vivo after implantation for 6 weeks. The results indicate that the required bioactivity and degradation rate may be achieved by substituting an appropriate amount of SiO2 in 13-93 glass with B2O3, and that these trabecular glass scaffolds could serve as substrates for the repair and regeneration of contained bone defects.

  9. Effect of glass structure on spin Hamiltonian parameters: Cu doped tellurite glasses

    NASA Astrophysics Data System (ADS)

    Ramamoorthy, Raj Kumar; Bhatnagar, Anil K.

    2015-06-01

    Cu-doped glasses with compositions [(70TeO2-(30-x)ZnO-xPbO)0.98- (CuO)0.02] (x = 5, 10, 15, 20) were prepared using the melt quenching technique and characterized by EPR. Cu2+ ions are found to be in distorted oxygen octahedral cage and their corresponding spin Hamiltonian (splitting) parameters are deduced for all glasses as a function of increasing PbO. Finally, effect of the matrix on spin Hamiltonian parameters of Cu2+ ions are correlated with the help of EPR and earlier Raman analysis.

  10. Effect of glass structure on spin Hamiltonian parameters: Cu doped tellurite glasses

    SciTech Connect

    Ramamoorthy, Raj Kumar; Bhatnagar, Anil K.

    2015-06-24

    Cu-doped glasses with compositions [(70TeO{sub 2}−(30−x)ZnO−xPbO){sub 0.98}− (CuO){sub 0.02}] (x = 5, 10, 15, 20) were prepared using the melt quenching technique and characterized by EPR. Cu{sup 2+} ions are found to be in distorted oxygen octahedral cage and their corresponding spin Hamiltonian (splitting) parameters are deduced for all glasses as a function of increasing PbO. Finally, effect of the matrix on spin Hamiltonian parameters of Cu{sup 2+} ions are correlated with the help of EPR and earlier Raman analysis.

  11. Oxyfluorotellurite glasses doped by dysprosium ions. Thermal and optical properties

    NASA Astrophysics Data System (ADS)

    Klimesz, Barbara; Ryba-Romanowski, Witold; Lisiecki, Radosław

    2015-04-01

    The paper shows results of investigation of thermal and optical properties of oxyfluorotellurite (65 - x)TeO2-20ZnF2-12Pb2O5-3Nb2O5-xDy2O3 (x = 0.5, 2 and 5) glass systems. Thermal stability and the onset of crystallization of the materials were monitored by differential thermal analysis (DTA). It was found that characteristic parameters, namely glass transition temperatures (Tg), onset of crystallization temperatures (Tc) and thermal stability criteria ΔT and H' increased with increasing Dy2O3 content indicating that the incorporation of dysprosium ions improves substantially thermal stability of glass system under study. Optical absorption and emission spectra of Dy3+ ions in oxyfluorotellurite glass were investigated at room temperature in the visible (VIS) and near-infrared (NIR) region. Oscillator strengths, phenomenological Judd-Ofelt (JO) intensity parameters Ω2,4,6, radiative transition probabilities, branching ratios and radiative lifetimes of luminescent levels were determined. Decay curves of the 4F9/2 luminescence of incorporated Dy3+ ions were recorded and analysed. Lifetimes and the luminescence dynamics were studied as a function of the Dy2O3 concentration. It was concluded that good thermal stability combined with desirable spectroscopic parameters of investigated dysprosium-doped oxyfluorotellurite glass point at the suitability of this material for the design of UV-excited visible phosphors.

  12. Lead-salt quantum dot doped glasses for photonics

    NASA Astrophysics Data System (ADS)

    Auxier, Jason Michael

    In this dissertation, I present photonics applications of PbS quantum-dot-doped (QD-doped) glasses. The dissertation consists of two major parts: bulk material applications (Cr:forsterite laser modelocking, bleaching dynamics, optical gain, and photo-luminescence) and the fabrication of QD-doped ion-exchanged waveguides. When this work began, these PbS QD-doped glasses were the state-of-the-art in quantum dot glasses due to their narrow size distribution. Modelocking of a Cr:forsterite laser using this glass as a saturable absorber had been demonstrated, with little understanding of the dynamics. This work began by studying the dynamics of the saturable absorber to explain the ps-pulse width. In the bulk measurements, I functioned as a secondary researcher. In the laser modelocking and bleaching measurements, my contribution was laser cavity alignment, sample preparation, collecting autocorrelation traces, and aiding in the setup and data collection for the bleaching measurements. On this work, I coauthored one refereed journal article in Applied Physics Letters [1] and one refereed conference paper [2], for which I am third and second author, respectively. For the gain measurements, I aided in the setup and data collection, whereas I setup and took most of the luminescence data. The gain measurements resulted in one second-author refereed journal article in Applied Physics Letters [3] and I presented the luminescence results at CLEO2000 [4]. I took the lead role in the waveguide fabrication and characterization and authored refereed journal articles in Applied Physics Letters [5], Journal of Applied Physics [6], and Journal of the Optical Society of America B [7]. I also presented an invited talk at Photonics West [8] and presented at CLEO200-1 [9]. Additionally, I have been a coauthor of presentations at the Nanotechnology Symposium (2006), American Ceramic Society [10], and Photonics Europe ( 2006) [11]. A book chapter in The Photonics Handbook, 2nd edition [12

  13. Luminescence properties of solid solutions of borates doped with rare-earth ions

    NASA Astrophysics Data System (ADS)

    Levushkina, V. S.; Mikhailin, V. V.; Spassky, D. A.; Zadneprovski, B. I.; Tret'yakova, M. S.

    2014-11-01

    The structural and luminescence properties of LuxY1 - xBO3 solid solutions doped with Ce3+ or Eu+3 have been investigated. It has been found that the solid solutions crystallize in the vaterite phase with a lutetium concentration x < 0.5. For a higher lutetium concentration x, the solid solutions contain an additional calcite phase with a content less than 5 wt %. The luminescence spectra are characterized by intensive impurity emission under excitation with the synchrotron radiation in the X-ray and ultraviolet spectral ranges. It has been shown that, as the lutetium concentration x in the LuxY1 - xBO3: Ce3+ solid solutions increases, the emission intensity smoothly decreases, which is associated with a gradual shift of the Ce3+ 5 d(1) level toward the bottom of the conduction band, as well as with a decrease in the band gap. It has been established that, in the LuxY1 - xBO3: Eu3+ solid solutions with intermediate concentrations x, the efficiency of energy transfer to luminescence centers increases. This effect is explained by the limited spatial separation of electrons and holes in the solid solutions. It has been demonstrated that the calcite phase adversely affects the luminescence properties of the solid solutions.

  14. Photon avalanche up-conversion in holmium doped fluoride glasses

    SciTech Connect

    Chen, Y.H.; Liu, G.K.; Beitz, J.V.; Jie Wang

    1996-08-01

    Photon avalanche green up-conversion emission centered at 545 nm has been observed in Ho{sup 3+} doped and Ho{sup 3+}, Tm{sup 3+} co-doped ZrF{sub 4}-based fluoride glasses when excited near 585 nm which is off resonance with any ground state absorption bands of either Ho{sup 3+} or Tm{sup 3+} ions. Detailed spectral measurements and analysis suggest that the 545 nm emission occurs from the {sup 5}S{sub 2},{sup 5}F{sub 4} states of Ho{sup 3+} that are populated by excited state absorption from the {sup 5}I{sub 7} state of Ho{sup 3+}. Strong cross-relaxation that efficiently populates the {sup 5}I{sub 7} state makes the photon avalanche process possible in this system.

  15. Er-doped and Er, Yb co-doped oxyfluoride glasses and glass-ceramics, structural and optical properties

    NASA Astrophysics Data System (ADS)

    Lisiecki, Radosław; Augustyn, Elżbieta; Ryba-Romanowski, Witold; Żelechower, Michał

    2011-09-01

    The selected glasses and glass-ceramics pertinent to following chemical composition in mol%:48%SiO 2-11%Al 2O 3-7%Na 2O-10%CaO-10%PbO-11%PbF 2-3%ErF 3 and 48%SiO 2-11%Al 2O 3-7%Na 2O-10%CaO-10%PbO-10%PbF 2-1%ErF 3-3%YbF 3 have been manufactured from high purity components (Aldrich) at 1450 °C in normal atmosphere. Glass optical fibers were successfully drawn. Subsequently they were subject to the heat-treatment at 700 °C in various time periods. The preceding differential thermal analysis (DTA) studies allowed estimating both the fiber drawing temperature and the controlled crystallization temperature of glass fibers. It has been observed that the controlled heat-treatment of oxyfluoride glass fibers results in the creation of Pb 5Al 3F 19, Er 4F 2O 11Si 3 and Er 3FO 10Si 3 crystalline phases. The identified phases were characterized by X-ray powder diffraction (XRD) and confirmed by selected area electron diffraction (SAED). The fibers consist of mixed amorphous-crystalline microstructure with nano-crystals of size even below 10 nm distributed in the glassy host. Their morphology was investigated applying high-resolution transmission electron microscopy. Optical properties and excited state relaxation dynamics of optically active ions (Er 3+, Yb 3+) in glass and glass-ceramics have been studied. Based on absorption spectra the Judd-Ofelt analysis was carried out. The main attention was directed to NIR luminescence at. 1.6 μm related to 4I 13/2 → 4I 15/2 Er 3+ and less effective emission associated with 4I 11/2 → 4I 15/2 Er 3+ and 2F 5/2 → 2F 7/2 Yb 3+ transitions. The dissimilar spectroscopic properties have been revealed for glasses and glass-ceramic samples, respectively. The reduction of emission linewidth at 1.6 and 1.0 μm combined with substantial increase of 4I 13/2 lifetimes of erbium in glass-ceramics appear to be evidences that Er 3+ ions are accommodated in crystalline phases. The structural and optical characteristics of oxyfluoride glass

  16. Dielectric relaxation in AgI doped silver selenomolybdate glasses

    NASA Astrophysics Data System (ADS)

    Palui, A.; Shaw, A.; Ghosh, A.

    2016-05-01

    We report the study of dielectric properties of some silver ion conducting silver selenomolybdate mixed network former glasses in a wide frequency and temperature range. The experimental data have been analyzed in the framework of complex dielectric permittivity. The dielectric permittivity data have been well interpreted using the Cole-Cole function. The temperature dependence of relaxation time obtained from real part of dielectric permittivity data shows an Arrhenius behavior. The activation energy shows a decreasing trend with the increase of doping content. Values of stretched exponential parameter are observed to be independent of temperature and composition.

  17. Energy upconversion in holmium doped lead-germano-tellurite glass

    SciTech Connect

    Kamma, Indumathi; Reddy, B. Rami

    2010-06-15

    Holmium doped lead-germano-tellurite glass was prepared by the melt quenching technique. The Judd-Ofelt intensity parameters were estimated as {Omega}{sub 2}=7.6x10{sup -20}, {Omega}{sub 4}=12.9x10{sup -20}, and {Omega}{sub 6}=2.5x10{sup -20} cm{sup 2}. Radiative transition probabilities and lifetimes were also determined for some of the levels. Room temperature upconversion emissions have been observed from Ho{sup 3+} at 497 nm under 532 nm laser excitation, and at 557 and 668 nm under 762 nm laser excitation. The upconversion emission mechanisms were found to be due to a step wise excitation process. Upconversion emission intensity enhanced in a heat treated glass.

  18. Spectroscopic properties of Nd3+-doped tungsten-tellurite glasses

    NASA Astrophysics Data System (ADS)

    Costa, F. B.; Yukimitu, K.; Nunes, L. A. O.; Figueiredo, M. S.; Andrade, L. H. C.; Lima, S. M.; Moraes, J. C. S.

    2016-01-01

    In this work, we investigate the spectroscopy properties of neodymium doped tungsten-tellurite glasses prepared in ambient and O2-rich atmospheres. A conversion of TeO4 to TeO3 units was caused by the addition of Nd3+ into the glass, which was confirmed by absorption spectra and by Judd-Ofelt parameter behavior. The relaxation of the 4F3/2 level is dominated by radiative decay and cross-relaxation between Nd3+ and Nd3+ ions. The energy transfer from Nd3+ to the hydroxyl group is negligible when compared to the cross-relaxation. The luminescence quantum efficiency values of the 4F3/2 level decreases as the Nd3+ concentration increases, independently if determined by the Judd-Ofelt method or by the thermal lens technique. The observed reduction in the IR absorption associated to OH groups was not effective to improve the luminescence quantum efficiency.

  19. Spectroscopic Studies on Eu3+ Doped Boro-Tellurite Glasses

    NASA Astrophysics Data System (ADS)

    Selvaraju, K.; Marimuthu, K.

    2011-07-01

    Eu3+ doped boro-tellurite glasses have been synthesized and its optical behavior have been studied and reported. The presence of varying tellurium dioxide content results changes in spectroscopic behavoir were explored through UV-VIS, and Luminescence spectra. The bonding parameters have been calculated based on the observed band positions of the absorption spectra. The Judd-Ofelt intensity parameters Ωλ (λ = 2, 4 and 6) have been determined through the luminescence spectra without applying any constraints and the results are presented. The Judd-Ofelt parameters have been used to determine various optical properties corresponding to 5D0→7FJ (J = 1,2,3 and 4) transitions of Eu3+ ions. The varying optical properties of the prepared glasses with the change in tellurium dioxide have been studied and compared with similar studies.

  20. Structure and luminescence of Dy3+ doped CaO-B2O3-SiO2 glasses

    NASA Astrophysics Data System (ADS)

    Hao, Yan; Cao, Ju

    2016-07-01

    The present work reports structure and luminescence of Dy3+ doped CaO-B2O3-SiO2 glasses prepared by melt quenching technique. The presence of various stretching and bending vibrations of different borate and silicate groups were identified from FTIR spectral measurements. The optical absorption and luminescence spectra were also measured, and their emission spectra exhibit two intense emission bands at around 485 nm (blue) and 577 nm (yellow) corresponds to 4F9/2→6H15/2 and 4F9/2→6H13/2 transitions, respectively. The emission spectra were characterized through CIE 1931 color chromaticity diagram to explore its suitability for W-LED applications. Furthermore, the proper Y2O3 could change local structure of glass, which makes the UV absorption edge shift to longer wavelength, and it's easier to transfer energy from host to Dy3+ and then enhance the emission of Dy3+.

  1. Silicate, borosilicate, and borate bioactive glass scaffolds with controllable degradation rate for bone tissue engineering applications. I. Preparation and in vitro degradation.

    PubMed

    Fu, Qiang; Rahaman, Mohamed N; Fu, Hailuo; Liu, Xin

    2010-10-01

    Bioactive glass scaffolds with a microstructure similar to that of dry human trabecular bone but with three different compositions were evaluated for potential applications in bone repair. The preparation of the scaffolds and the effect of the glass composition on the degradation and conversion of the scaffolds to a hydroxyapatite (HA)-type material in a simulated body fluid (SBF) are reported here (Part I). The in vitro response of osteogenic cells to the scaffolds and the in vivo evaluation of the scaffolds in a rat subcutaneous implantation model are described in Part II. Scaffolds (porosity = 78-82%; pore size = 100-500 microm) were prepared using a polymer foam replication technique. The glasses consisted of a silicate (13-93) composition, a borosilicate composition (designated 13-93B1), and a borate composition (13-93B3), in which one-third or all of the SiO2 content of 13-93 was replaced by B2O3, respectively. The conversion rate of the scaffolds to HA in the SBF increased markedly with the B2O3 content of the glass. Concurrently, the pH of the SBF also increased with the B2O3 content of the scaffolds. The compressive strengths of the as-prepared scaffolds (5-11 MPa) were in the upper range of values reported for trabecular bone, but they decreased markedly with immersion time in the SBF and with increasing B2O3 content of the glass. The results show that scaffolds with a wide range of bioactivity and degradation rate can be achieved by replacing varying amounts of SiO(2) in silicate bioactive glass with B2O3.

  2. Lead-barium fluoroborate glass ceramics doped with Nd3+ or Er3+

    NASA Astrophysics Data System (ADS)

    Petrova, O. B.; Sevostjanova, T. S.; Anurova, M. O.; Khomyakov, A. V.

    2016-02-01

    Lead-barium fluoroborate glasses in the PbF2-BaF2-B2O3, PbF2-BaO-B2O3, and PbO- BaF2-B2O3 systems doped with rare-earth ions (Nd3+ or Er3+) are synthesized and studied. It is shown that, based on these glasses, it is possible to produce transparent glass ceramics with fluoride crystalline phases, including ceramics with one crystalline phase of the fluorite structure. The spectral and luminescent properties of the doped glasses, glass ceramics, and polycrystalline complex fluorides containing Pb, Ba, and rare ions are studied.

  3. Doping of ZnO nanowires using phosphorus diffusion from a spin-on doped glass source

    SciTech Connect

    Bocheux, A.; Robin, I. C.; Bonaimé, J.; Hyot, B.; Feuillet, G.; Kolobov, A. V.; Fons, P.; Mitrofanov, K. V.; Tominaga, J.; Tamenori, Y.

    2014-05-21

    In this article, we report on ZnO nanowires that were phosphorus doped using a spin on dopant glass deposition and diffusion method. Photoluminescence measurements suggest that this process yields p-doped ZnO. The spatial location of P atoms was studied using x-ray near-edge absorption structure spectroscopy and it is concluded that the doping is amphoteric with P atoms located on both Zn and O sites.

  4. The Effect of TiO2 and MgO on the Thermoluminescence Properties of a Lithium Potassium Borate Glass System

    NASA Astrophysics Data System (ADS)

    Alajerami, Y. S. M.; Hashim, S.; Ghoshal, S. K.; Saleh, M. A.; Kadni, T.; Saripan, M. I.; Alzimami, K.; Ibrahim, Z.; Bradley, D. A.

    2013-12-01

    The influence of dopant TiO2 and co-dopant MgO on the thermoluminescence (TL) properties of lithium potassium borate glass (LKB) is reported in this paper. The glow curve exhibits a prominent peak (Tm) at 230 °C. The TL intensity was enhanced by a factor of ~3 due to the incorporation of MgO, and this was attributed to the creation of extra electron traps mediated by radiative recombination energy transfer. We achieved good linearity of the TL yield with dose, low fading, excellent reproducibility and a promising effective atomic number (Zeff=8.89), all of which are highly suitable for dosimetry. The effect of heating rate, sunlight and dose rate on the TL are also examined. These attractive features demonstrate that our dosimeter is useful in medical radiation therapy.

  5. Concentration dependent spectroscopic properties of Sm3+ doped borophosphate glasses

    NASA Astrophysics Data System (ADS)

    Vijayakumar, R.; Marimuthu, K.

    2015-07-01

    A new series of Sm3+ doped borophosphate glasses 50B2O3 + 20Li2CO3 + 10ZnO + 9SrCO3 + (11 - x)P2O5 + xSm2O3 (x = 0.1, 0.25, 0.5, 1 and 2 in wt%) have been prepared by following melt quenching technique. The structural and optical properties of the prepared glasses were characterized through XRD, FTIR, absorption, luminescence and decay spectral measurements. The XRD spectrum exhibit broad diffusion at lower angles which reveal the amorphous nature and the presence of various functional groups such as Psbnd Osbnd P bonds, Bsbnd O vibrations in BO3 units and Psbnd OH and Bsbnd OH bonds in the title glasses were confirmed through the FTIR spectra. The nature of the metal-ligand bonding and the electronic band structure has been investigated using the absorption spectra. The Judd-Ofelt (JO) intensity parameters (Ω2, Ω4 and Ω6) were evaluated from the JO theory using the refractive index and the experimental oscillator strength values. The emission spectra exhibit four emission bands in the visible region corresponding to the 4G5/2 → 6H5/2, 4G5/2 → 6H7/2, 4G5/2 → 6H9/2 and 4G5/2 → 6H11/2 transitions by monitoring an excitation wavelength at 403 nm. The emission spectra have been characterized through Commission International de I'Eclairage (CIE) 1931 chromaticity diagram to explore the dominant emission from the studied glasses. The radiative parameters such as transition probability (AR), branching ratios (βR) and stimulated emission cross-section ( σPE) were obtained for the emission transitions using JO parameters and the results were discussed and compared with the reported literature.

  6. Effect of doping of Nd3+ ions in BaO-TeO2-B2O3 glasses: A vibrational and optical study

    NASA Astrophysics Data System (ADS)

    Nanda, Kirti; Berwal, Neelam; Kundu, R. S.; Punia, R.; Kishore, N.

    2015-05-01

    Nd3+ ions doped Barium-Tellurite-Borate glasses with compositions xNd2O3 - (100 - x)[0.1BaO-0.4TeO2-0.5B2O3]; x = 0.0, 0.5, 1.0, 1.5 and 2.0 have been prepared by melt-quench technique. The amorphous nature of as-prepared glasses has been confirmed by X-ray diffraction patterns. The density, molar volume and equivalent crystalline volume of the glass samples have been found to increase with the increase in concentration of Nd2O3. FTIR and Raman spectra of the prepared glasses indicate that Nd2O3 acts as glass modifier and as the content of Nd2O3 increases, BO4 structural units are converted into BO3 structural units. The values of optical band gap have been estimated from the fitting of Mott and Davis's model with the experimentally observed absorption spectra. The experimentally observed spectra of absorption coefficient also show good agreement with the hydrogenic excitonic model and the values of different parameters like optical band gap, excitonic binding energy, line width of m = 1 state and line width of continuum have been estimated from theoretical fitting of this model. The values of optical band gap are observed to decrease with increase in concentration of Nd2O3.

  7. Thermal, structural and spectroscopic properties of heavy metal oxide glass and glass-ceramics doped with Er3+ ions

    NASA Astrophysics Data System (ADS)

    Ragin, Tomasz; Zmojda, Jacek; Kochanowicz, Marcin; Miluski, Piotr; Jelen, Piotr; Sitarz, Maciej; Dorosz, Dominik

    2015-09-01

    In this paper, bismuth-germanate oxide glass doped with erbium ions has been synthesized. Composition of the glass has been chosen in terms of the low phonon energy and good transparency in the infrared region. Transparent glass-ceramics sample has been prepared by controlled crystallization process. Fourier transform infrared spectroscopy (FTIR) has been used to determinate structural properties of samples. The absorption coefficient, the luminescence intensity in visible and infrared region and the differential scanning calorimetry have been examined. Difference in the emission intensity and shape of the luminescence bands indicates the presence of crystalline phases in obtained glass-ceramics sample.

  8. Enhanced emissions in Tb3+-doped oxyfluoride scintillating glass ceramics containing BaF2 nanocrystals

    NASA Astrophysics Data System (ADS)

    Huang, Lihui; Jia, Shijie; Li, Yang; Zhao, Shilong; Deng, Degang; Wang, Huanping; Jia, Guohua; Hua, Youjie; Xu, Shiqing

    2015-07-01

    Transparent Tb3+-doped glass ceramics containing BaF2 nanocrystals were prepared by melt-quenching method with subsequent heat treatment. The XRD and EDS results showed the precipitated crystalline phase in the glass matrix was BaF2. Under 376 nm light, Tb3+ doped oxyfluoride glass ceramics containing BaF2 nanocrystals showed more intense green emission than the as-made glass, and the emission intensity increased with increasing heat treatment temperature and time. The lifetimes of 541 nm emission of Tb3+ doped oxyfluoride glass ceramics were longer than that of as-made glass, which are in the range from 3.00 ms to 3.55 ms. Under X-ray excitation, the green emission was enhanced in the glass ceramics compared to the as-made glass. The results indicate Tb3+ doped oxyfluoride glass ceramics containing BaF2 nanocrystals could be a material candidate for X-ray glass scintillator for slow event detection.

  9. Photonic bandgap single-mode optical fibre with ytterbium-doped silica glass core

    SciTech Connect

    Egorova, O N; Semenov, S L; Vel'miskin, V V; Dianov, Evgenii M; Salganskii, M Yu; Yashkov, M V; Gur'yanov, Aleksei N

    2011-01-24

    A photonic bandgap fibre with an ytterbium-doped silica glass core is fabricated and investigated. The possibility of implementing single-mode operation of such fibres in a wide spectral range at a large (above 20 {mu}m) mode field diameter makes them promising for fibre lasers and amplifiers. To ensure a high quality of the beam emerging from the fibre, particular attention is paid to increasing the optical homogeneity of the ytterbium-doped core glass. (optical fibres)

  10. Luminescence efficiency growth in wide band gap semiconducting Bi2O3 doped Cd0.4Pb0.1B0.5 glasses and effect of γ-irradiation

    NASA Astrophysics Data System (ADS)

    Marzouk, M. A.; Ibrahim, S.; Hamdy, Y. M.

    2014-11-01

    Cadmium lead borate glasses together with other glasses containing different Bi2O3-doping concentrations (2.5, 5, 7.5, 10 mol%) were prepared by conventional melt annealing method. The density and molar volume values were calculated to obtain some insight on the packing density and arrangement in the network. Also their optical and structural properties have been characterized by means of X-ray diffraction, UV-visible spectroscopy, luminescence spectroscopy and FTIR spectroscopy. Optical measurements have been used to determine the optical band gap (Eg), Urbach energy (ΔE) and the refractive index (n). The results demonstrate the effective rule of Bi2O3 on the studied glasses. The undoped and Bi2O3 doped - glass show strong extended UV-near visible absorption bands which are attributed to the collective presence of both trace iron impurities from raw materials and also the sharing of bismuth Bi+3 ions. Furthermore, the luminescence intensity strongly increases with increasing Bi2O3 content which may be attributed to transfer of energy from transitions in its energy levels. It has been revealed that the decreasing values of optical band gap and band tail can be understood and related in terms of the structural changes that are taking place in the glass samples. The infrared absorption spectra of the prepared glasses show characteristic absorption bands related to the borate network (BO3, BO4 groups) together with vibrational modes due to Bi-O groups upon the introduction of Bi2O3. The prepared samples reveal a very limited response towards of gamma irradiation which reflects its shielding behavior towards the effect of such type of irradiation.

  11. Efficient radioluminescence of the Ce3+-doped Na-Gd phosphate glasses

    NASA Astrophysics Data System (ADS)

    Nikl, M.; Nitsch, K.; Mihokova, E.; Solovieva, N.; Mares, J. A.; Fabeni, P.; Pazzi, G. P.; Martini, M.; Vedda, A.; Baccaro, S.

    2000-10-01

    Photo- and radioluminescence, decay kinetics, and thermoluminescence are reported for a set of Ce3+-doped phosphate glasses. The presence of Gd3+ ions in the glass host matrix at concentrations above 20% enhances the energy transfer towards the Ce3+ emission centers, which results in a remarkable enhancement of the radioluminescence light output.

  12. Luminescence properties of gallium phosphate glass doped with trivalent titanium ions

    SciTech Connect

    Batyaev, I.M.; Golodova, I.V.

    1994-07-01

    Luminescence properties of gallium phosphate glasses doped with trivalent titanium ions are studied. The glasses luminesce in the 680- to 880-nm region (the {sup 2}E{sub g}-{sup 2}T{sub 2g} transition in the distorted octahedral field) and can be used as matrices for the development of luminophors in the near infrared region. 8 refs., 2 figs.

  13. Study on the preparation and properties of silver-doped phosphate antibacterial glasses (Part I)

    NASA Astrophysics Data System (ADS)

    Ahmed, A. A.; Ali, A. A.; Mahmoud, Doaa A. R.; El-Fiqi, A. M.

    2011-05-01

    Silver-doped phosphate antibacterial glasses were prepared by the melting method. The antibacterial effects of some undoped and silver-doped glasses of compositions 65P 2O 5-10CaO-(25- x) Na 2O, 70P 2O 5-20CaO-(10- x) Na 2Oand (70- x) P 2O 5-30CaO, (where x = 0, 0.5, 1.2 Ag 2O), against Staphylococcus aureus, Pseudomonas aeruginosa and Escherichia coli micro-organisms using agar disk-diffusion assays were investigated. The structures of some glasses were studied by XRD, FT-IR, and UV-VIS spectroscopy. The variation of pH with dissolution rate was studied. The tested silver-free and silver-doped glasses demonstrated different antibacterial effects against the tested micro-organisms. For silver-free glasses, an increase in inhibition zone diameter (zone of no bacterial growth) was seen with the decrease in water pH. Silver-doped glasses showed an increase in inhibition zone diameter with increasing Ag 2O content. The low pH produced by glass dissolution was certainly a critical factor for glass antibacterial effect. The more the phosphate ions released the lower is the pH and the greater the antibacterial effect.

  14. Study of vibrational spectroscopy, linear and non-linear optical properties of Sm3+ ions doped BaO-ZnO-B2O3 glasses

    NASA Astrophysics Data System (ADS)

    Nanda, Kirti; Kundu, R. S.; Sharma, Sarita; Mohan, Devendra; Punia, R.; Kishore, N.

    2015-07-01

    Samarium oxide doped Barium-Zinc-Borate glasses with compositions xSm2O3-(100-x)[0.1BaO-0.4ZnO-0.5B2O3]; x = 0.0, 0.5, 1.0, 1.5 and 2.0 have been prepared by melt quench technique. The amorphous nature of as-prepared glasses has been ascertained by X-ray diffraction patterns. The observed values of density and molar volume of the glass samples are found to increase with the increase in concentration of Sm2O3. Fourier Transform Infrared spectra of the prepared glasses indicate that Sm2O3 acts as glass modifier. With the increase in Sm2O3 content, BO4 structural units start converting into BO3 structural units. The values of optical energy band gap (Eg), estimated from Tauc's plots, are observed to decrease with the increase in Sm2O3 content. The nonlinear optical properties of glass samples have been investigated by Z-scan method with nanosecond pulsed laser at ˜532 nm in both open and close aperture geometries. The values of two photon absorption coefficient (β) and nonlinear refractive index (n2) have been estimated by fitting of experimentally observed data with theoretical models and both are found to increase with the increase in Sm3+ ions concentration in the glass matrix. The total third order nonlinear susceptibility (χ(3)) have been calculated and observed to increase with the increase in Sm3+ ions concentration.

  15. Thermal analysis and luminescence of phospho-tellurite glass doped with NdF3

    NASA Astrophysics Data System (ADS)

    Iwanowicz, Kamil; Dorosz, Dominik; Żmojda, Jacek; Kochanowicz, Marcin

    2015-09-01

    In the paper thermal and luminescence properties of phospho-tellurite glass and glass after thermal treatment doped with NdF3 were presented. The crystallization kinetic of the main crystallization peaks of glass was investigated using differential scanning calorimetry (DSC). The value of the activation energy for crystalline phase (Ec 54,21 +/- 5 kJ mol-1) was calculated using Ozawa-Flynn-Wall (OFW), Kissinger-Akahira-Sunose (KAS), Starink and Tang methods. The glass-ceramic was obtained by heat treatment method. The luminescence transitions from levels 4F5/2 --> 4I9/2 (878 nm), 4F3/2-->4I11/2 (1058 nm), and 4F3/2 --> 4I13/2 (1330 nm) in glass and glass-ceramic doped NdF3 were compered.

  16. Study of optical properties of Erbium doped Tellurite glass-polymer composite

    SciTech Connect

    Sushama, D.

    2014-10-15

    Chalcogenide glasses have wide applications in optical device technology. But it has some disadvantages like thermal instability. Among them Tellurite glasses exhibits high thermal Stability. Doping of rare earth elements into the Tellurite glasses improve its optical properties. To improve its mechanical properties composites of this Tellurite glasses with polymer are prepared. Bulk samples of Er{sub 2}O{sub 3} doped TeO{sub 2}‐WO{sub 3}‐La{sub 2}O{sub 3} Tellurite glasses are prepared from high purity oxide mixtures, melting in an alumina crucible in air atmosphere. Composites of this Tellurite glasses with polymer are prepared by powder mixing method and the thin films of these composites are prepared using polymer press. Variations in band gap of these composites are studied from the UV/Vis/NIR absorption.

  17. Yb3+ doped fluorophosphate laser glasses with high gain coefficient and improved laser property

    NASA Astrophysics Data System (ADS)

    Wang, P. F.; Peng, B.; Li, W. N.; Hou, Ch. Q.; She, J. B.; Guo, H. T.; Lu, M.

    2012-04-01

    Yb3+ doped fluorophosphate glasses with high stimulated emission cross-section, large gain coefficient and low hydroxyl absorption coefficient were prepared by high temperature melting for fiber laser applications, and their spectral, general laser parameters were investigated accordingly by means of fluorescence emission spectrum, decay cure and infrared absorption spectra. Compared with previously reported fluorophosphate glasses, the investigated fluorophosphate glasses have highest grain coefficient and maintain a maximum laser systematical factor over other various types of laser glasses. The introduction of fluorides to fluorophosphate glasses results in the low level of hydroxyl absorption coefficient and concentration. All these advantages might mean that Yb3+ doped fluorophosphate glasses are a good candidate as an active laser media for short pulse, high power laser generation used for next generation nuclear fusion.

  18. Raman and Photoluminescence Spectroscopy of Er(3+) Doped Heavy Metal Oxide Glasses

    NASA Technical Reports Server (NTRS)

    Dyer, Keith; Pan, Zheng-Da; Morgan, Steve

    1997-01-01

    The potential applications of rare-earth ion doped materials include fiber lasers which can be pumped conveniently by infrared semiconductor laser diodes. The host material systems most widely studied are fluoride crystals and glasses because fluorides have low nonradiative relaxation rates due to their lower phonon energies. However, the mechanical strength, chemical durability and temperature stability of the oxide glasses are generally much better than fluoride glasses. The objective of this research was to investigate the optical and spectroscopic properties of Er(3+)-doped lead-germanate and lead-tellurium-germanate glasses. The maximum vibrational energy of lead-tellurium-germanate glasses are in the range of 740-820/cm, intermediate between those of silicate (1150/cm) and fluoride (530/cm) glasses.

  19. Ho(3+)-doped nanophase glass ceramics for efficiency enhancement in silicon solar cells.

    PubMed

    Lahoz, Fernando

    2008-12-15

    Currently Er(3+)-doped fluorides are being used as upconversion phosphors to enhance the efficiency of Si solar cells, to our knowledge. However, this enhancement is strongly limited owing to the small solar spectral range around 1540 nm that is used. We demonstrate that Ho(3+)-doped oxyfluoride glass ceramics are adequate to enlarge the Si sub-bandgap region around 1170 nm that can be transformed into higher-energy photons, showing an upconversion efficiency 2 orders of magnitude higher than the precursor glass. As these materials are transparent at 1540 nm, they can be used complementarily with Er(3+)-doped phosphors for the same purpose.

  20. Low-threshold lasing at 1975 nm in thulium-doped tellurite glass microspheres.

    PubMed

    Vanier, Francis; Côté, François; Amraoui, Mohammed El; Messaddeq, Younès; Peter, Yves-Alain; Rochette, Martin

    2015-11-15

    Thulium-doped (Tm-doped) tellurite glass microspheres are used as laser media. Emission lines at wavelengths near 1975 nm are observed. The onset of laser emission is achieved with 8.6 and 30 μW of coupled pump power and injected pump power, respectively, at a wavelength of 1554 nm. To the authors' knowledge, these are the lowest laser threshold values recorded for a Tm-doped tellurite glass microcavity. Intrinsic Q-factors above 10(6) for the undoped tellurite glass microspheres assert the quality of the fabrication processes. An optical intrinsic Q-factor comparison between Tm-doped tellurite and undoped tellurite microspheres shows that ion absorption is the dominant loss source at pump wavelengths. Lower lasing threshold powers and higher power conversion are observed at longer pump wavelengths in agreement with theoretical models. PMID:26565841

  1. Optical absorption and emission properties of Nd3+-doped oxyfluorosilicate glasses for solid state lasers

    NASA Astrophysics Data System (ADS)

    Ramachari, D.; Rama Moorthy, L.; Jayasankar, C. K.

    2014-11-01

    Optical absorption and near-infrared luminescent properties of Nd3+ ions doped oxyfluorosilicate (NKZLSNd) glasses were investigated. Raman spectrum was recorded to investigate the structural properties of NKZLSNd glasses. The Judd-Ofelt theory (JO) has been applied to the absorption spectrum of 1.0 mol% Nd3+-doped oxyfluorosilicate glass to derive the JO intensity parameters (Ωλ), which are in turn used to calculate the radiative properties of Nd3+ ions luminescent levels. The near-infrared emission spectra recorded with 808 nm laser diode excitation revealed the effective bandwidths values around 30-40 nm for the 4F3/2 level of Nd3+-doped oxyfluorosilicate glasses. The measured decay times of 4F3/2 level decreased with increasing Nd3+ ions concentration due to the concentration quenching.

  2. Pulsed laser deposition of rare-earth-doped glasses: a step toward lightwave circuits

    NASA Astrophysics Data System (ADS)

    Morea, R.; Fernandez, J.; Balda, R.; Gonzalo, J.

    2016-02-01

    Pulsed Laser Deposition (PLD) is used to produce Er-doped lead-niobium germanate (PbO-Nb2O5-GeO2) and fluorotellurite (TeO2-ZnO-ZnF2) thin film glasses. Films having high refractive index, low absorption and large transmission are obtained in a narrow processing window that depends on the actual PLD configuration (O2 pressure ˜a few Pa, Laser energy density ˜2-3 J cm-2 for the results presented in this work). However, Er-doped thin film glasses synthetized at room temperature using these experimental parameters show poor photoluminescence (PL) performance due to non-radiative decay channels, such as a large OH- concentration. Thermal annealing allows improving PL intensity and lifetime (τPL), the latter becoming close to that of the parent Er-doped bulk glass. In addition, the use of alternate PLD from host glass and rare-earth targets allows the synthesis of nanostructured thin film glasses with a controlled rare-earth concentration and in-depth distribution, as it is illustrated for Er-doped PbO-Nb2O5-GeO2 film glasses. In this case, PL intensity at 1.53 μm increases with the spacing between Er-doped layers to reach a maximum for a separation between Er-doped layers >= 5 nm, while τPL is close to the bulk value independently of the spacing. Finally, the comparison of these results with those obtained for films grown by standard PLD from Er-doped glass targets suggests that nanostructuration allows reducing rare-earth clustering and concentration quenching effects.

  3. Nonlinear-optic and ferroelectric behavior of lithium borate{endash}strontium bismuth tantalate glass{endash}ceramic composite

    SciTech Connect

    Senthil Murugan, G.; Varma, K. B. R.; Takahashi, Yoshihiro; Komatsu, Takayuki

    2001-06-18

    Transparent glasses in the system (100{endash}x) Li{sub 2}B{sub 4}O{sub 7}{endash}xSrBi{sub 2}Ta{sub 2}O{sub 9} (0{le}x{le}20) were fabricated via a splat-quenching technique. The glassy nature of the as-quenched samples was established by differential thermal analyses. X-ray powder diffraction and transmission electron microscopic studies confirmed the amorphous nature of the as-quenched and crystallinity (40 nm) in the heat-treated (glass{endash}ceramic) samples. The dielectric constant ({epsilon}{sub r}) of the glass{endash}ceramic composite (x=20, heat treated at 773 K/8 h) was in between that of the parent host glass (Li{sub 2}B{sub 4}O{sub 7}) and strontium bismuth tantalate ceramics in the frequency range 100 Hz{endash}40 MHz at 300 K. These exhibited intense second-harmonic generation and a ferroelectric hysteritic behavior (P vs E loops) at 300 K. The coercive field (E{sub c}) and the remnant polarization (P{sub r}) were 1053 V/cm and 0.483 {mu}C/cm2, respectively. {copyright} 2001 American Institute of Physics.

  4. X-ray absorption studies of gamma irradiated Nd doped phosphate glass

    SciTech Connect

    Rai, V. N.; Rajput, Parasmani; Jha, S. N.; Bhattacharyya, D.

    2015-06-24

    This paper presents the X-ray absorption near edge structure (XANES) studies of Nd doped phosphate glasses before and after gamma irradiation. The intensity and location of L{sub III} edge white line peak of Nd changes depending on its concentration as well as on the ratio of O/Nd in the glass matrix. The decrease in the peak intensity of white line after gamma irradiation indicates towards reduction of Nd{sup 3+} to Nd{sup 2+} in the glass matrix, which increases with an increase in the doses of gamma irradiation. Similarity in the XANES spectra of Nd doped phosphate glasses and Nd{sub 2}O{sub 3} suggests that coordination geometry around Nd{sup 3+} in glass samples may be identical to that of Nd{sub 2}O{sub 3}.

  5. Thermal degradation of ultrabroad bismuth NIR luminescence in bismuth-doped tantalum germanate laser glasses.

    PubMed

    Wang, Liping; Zhao, Yanqi; Xu, Shanhui; Peng, Mingying

    2016-04-01

    Because of ultra-broadband luminescence in 1000-1700 nm and consequent applications in fiber amplifier and lasers in the new spectral range where traditional rare earth cannot work, bismuth-doped laser glasses have received rising interest recently. For long-term practical application, thermal degradation must be considered for the glasses. This, however, has seldom been investigated. Here we report the thermal degradation of bismuth-doped germanate glass. Heating and cooling cycle experiments at high temperature reveal strong dependence of the thermal degradation on glass compositions. Bismuth and tantalum lead to the reversible degradation, while lithium can produce permanent irreversible degradation. The degradation becomes worse as lithium content increases in the glass. Absorption spectra show this is due to partial oxidation of bismuth near-infrared emission center. Surprisingly, we notice the emission of bismuth exhibits blueshift, rather than redshift at a higher temperature, and the blueshift can be suppressed by increasing the lithium content. PMID:27192231

  6. Short vertical tube furnace for the fabrication of doped glass microsphere lasers.

    PubMed

    Ward, Jonathan M; Wu, Yuqiang; Khalfi, Krimo; Nic Chormaic, Síle

    2010-07-01

    We report on the design of an electric tube furnace that can be used for the fabrication of doped glass microsphere lasers. The tube furnace has a short hot zone of length 133 mm and is based on a quartz tube design. Doped laser glass particles, specifically Er:Yb phosphate glass (IOG-2), of approximately 1 microm diameter are blown into the furnace using a 60 ml syringe and microspheres ranging in size from 10 to 400 microm are collected at the output of the tube furnace in a Petri dish. The furnace operates at a wall temperature of approximately 900 degrees C and is capable of making microspheres from glasses with glass transition temperatures of at least 375 degrees C. High quality (Q approximately 10(5)) whispering gallery modes have been excited within the microspheres by optically pumping at 978 nm via a tapered optical fiber. PMID:20687704

  7. Multi-functionality of luminescent glasses for energy applications

    NASA Astrophysics Data System (ADS)

    Steudel, F.; Loos, S.; Ahrens, B.; Schweizer, S.

    2015-09-01

    Rare-earth-(RE) doped barium borate glasses are investigated for their potential use as photon downshifting cover glasses for CdTe solar cells and as converters for white light-emitting diodes (LEDs). The glasses are doped with trivalent RE ions such as Eu3+ and Tb3+, resulting in an intense luminescence in the red (Eu3+) and green (Tb3+) spectral range upon excitation in the ultraviolet and blue ranges. Doping the glasses with two different RE ions enables broader absorption, which is necessary for both photovoltaic applications and for the appropriate color mixing needed for use in white LEDs. Though the single-doped cover glasses already reveal a slight increase in the short-circuit current density of CdTe solar cells, the double-doped glasses allow for even higher efficiency gains due to the significantly broader spectral range for absorption. For an Eu3+/Tb3+ double-doped glass with an RE doping level of 1 at.% each, an efficiency increase of 1.32% can be achieved. Furthermore, the Eu3+/Tb3+ double-doped glasses enable appropriate color mixing in the green-to-red spectral range by varying the RE doping level accordingly.

  8. Evaluation of Silica-based/Nickel and Borate-based/ Silver Glass Composites Seals for Solid Oxide Fuel Cells

    NASA Astrophysics Data System (ADS)

    Aguilar-Diaz, Yaneth

    The increasing demand for energy and the necessity to overcome the depletion of fossil fuel supplies requires that alternative energy sources be developed. Solid Oxide Fuel Cells (SOFCs) are one of the alternative technologies to minimise our dependence on fossil fuel due to their numerous advantages including high efficiency, long-term stability, fuel flexibility and low emissions. However, the development of reliable sealing techniques remains a crucial challenge to overcome to allow usable efficiency and facilitate commercialization. Sealing technology has been object of research for several years. Nevertheless, the optimal solution is yet to be found. The use of a glass composite approach is attractive as it allows the possibility of engineering the properties of the seal, by independently adjusting the particle size distribution and volume fraction of the additives. In the present work, the interaction between various SiO2 based glasses with nickel and B2O3 based glasses with silver were studied. Results as a function of additive particle size distribution (7-100 microns) and volume fraction (0-18%) will be presented. Micrographs, X-ray patterns and CTE measurements showed that the proposed systems have adequate characteristics for usage as seal for fuel cells due to the inertness of the additive particles with the respective glass matrix and predictable long-term chemical and thermal stability. The use of DTMA as a technique to calculate the onset of residual stresses, explores the influence of the additive and its interfacial interactions on the dissipation of energy during deformation. The multi-frequency test lead to an activation energy for stress relaxation between 400 and 600 kJ/mol depending on the different additive content. Furthermore, the temperature difference between de Tg and the onset of residual stresses was calculated showing that increments on the additive content results on a larger temperature range that allows stress relaxation. The

  9. Lead-gallium glasses and glass-ceramics doped with SiO2 for near infrared transmittance

    NASA Astrophysics Data System (ADS)

    Marczewska, Agnieszka; Środa, Marcin; Nocuń, Marek; Sulikowski, Bogdan

    2015-07-01

    Lead-gallium glasses, due to the absence of typical glass-forming components, are characterized by an increased tendency to crystallization. Despite this, they are interesting materials due to a shift of IR absorption edge up to 6-7 μm. The paper considers how the SiO2 dopant affects thermal stability and the UV-VIS and IR transmittance of lead-gallium glasses. The base lead-gallium glass (0.75PbO·0.25Ga2O3) was modified by the addition of 5, 10 and 15 mol% SiO2, respectively. DTA/DSC data showed that the glasses are characterized by the multi-stage crystallization, which is changed with the amount of silica doped. The XRD analysis confirmed that: (i) different forms of lead oxide crystallize after heat treatment of the glass, and (ii) the Ga2PbO4 phase is formed at higher temperatures. The silica admixture allowed inserting a few percent of BaF2 into the lead-gallium glass structure. It was found that a transparent glass-ceramic based on the lead-gallium glass with a low phonon barium fluoride phase can be obtained during the thermal treatment. The study of UV-VIS-IR transmittance shows that 10-15 mol% SiO2 in the lead-gallium glasses diminishes the absorption band in the range of 2.6-4 μm due to the presence of hydroxyl groups and simultaneously reduces transmittance in the range of 5-6.5 μm from 10 to 20%. Introduction of SiO2 to the glass results in the increase of transmittance in the shorter wavelength region and the UV-edge shift is observed. It was also confirmed that the BaF2 nanocrystallites exert no effect on the transmittance of the spectrum analyzed.

  10. Crystal growth and optical properties of CdS-doped lead silicate glass

    SciTech Connect

    Liu Hao; Liu Qiming; Zhao Xiujian . E-mail: zhaoxj@public.wh.hb.cn

    2007-01-15

    The crystal growth and optical properties of CdS microcrystallite-doped lead silicate glass is investigated in this paper. The existence of CdS nanocrystals was confirmed via X-ray diffraction (XRD) and transmission electron microscopy (TEM). Results reveal that a two-stage heat-treat procedure can produce a better size distribution of CdS nanocrystals than a one-stage heat-treat procedure in glasses. The second harmonic generation (SHG) from the base glass and CdS microcrystallite doped glasses was observed, and the effects of the heat treatments and the thermal poling temperature on the crystallization of CdS and second-order harmonic (SH) intensity were discussed, respectively. It is indicated that samples doped with CdS microcrystallite showed larger SH intensity than that of the base glass. Use of a higher thermal poling temperature than the glass transformation temperature does not result in a good SH intensity in glasses.

  11. Luminescent properties of Ln3+ doped tellurite glasses containing AlF3

    NASA Astrophysics Data System (ADS)

    Walas, Michalina; Pastwa, Agata; Lewandowski, Tomasz; Synak, Anna; Gryczyński, Ignacy; Sadowski, Wojciech; Kościelska, Barbara

    2016-09-01

    The low-phonon energy tellurite glasses TeO2-BaO-Bi2O3 and TeO2-BaO-Bi2O3-AlF3 triply doped with Eu3+, Tb3+, Tm3+ ions in two different molar ratios were synthesized using melt-quenching technique. Their structure and luminescence properties were widely investigated by X-ray Diffraction (XRD), Differential Scanning Calorimetry (DSC), Fourier Transform Infrared Spectroscopy (FTIR) and Photoluminescence Spectroscopy (PL). The luminescence spectra of Eu3+, Tb3+, Tm3+ co-doped glasses show apart of the bands corresponding to the 4f-4f transitions of lanthanide ions also band corresponding to glass matrix. AlF3 doping increases emission intensity, although to improve overall emission color further studies on molar composition of samples and the molar ratio of the components should be carried out.

  12. Determining the 6Li doped side of a glass scintillator for ultra cold neutrons

    NASA Astrophysics Data System (ADS)

    Jamieson, Blair; Rebenitsch, Lori Ann

    2015-08-01

    Ultracold neutron (UCN) detectors using two visually very similar, to the microscopic level, pieces of optically contacted cerium doped lithium glasses have been proposed for high rate UCN experiments. The chief difference between the two glass scintillators is that one side is 6Li depleted and the other side 6Li doped. This note outlines a method to determine which side of the glass stack is doped with 6Li using AmBe and 252Cf neutron sources, and a Si surface barrier detector. The method sees an excess of events around the α and triton energies of neutron capture on 6Li when the enriched side is facing the Si surface barrier detector.

  13. Structural properties of fluorozirconate-based glass ceramics doped with multivalent europium

    SciTech Connect

    PaBlick, C.; Müller, O.; Lützenkirchen-Hecht, D.; Frahm, R.; Johnson, J.A.; Schweizer, S.

    2012-10-10

    The structure/property relationships of fluorochlorozirconate glass ceramics as a function of divalent and trivalent europium (Eu) co-doping and thermal processing have been investigated; the influence of doping ratio on the formation of barium chloride (BaCl2) nanocrystals therein was elucidated. X-ray absorption near-edge structure spectroscopy shows that the post-thermal annealing changes the Eu valence of the as-poured glass slightly, but during the melting process Eu3+ is more strongly reduced to Eu2+, in particular, when doped as a chloride instead of fluoride compound. The Eu2+-to-Eu3+ doping ratio also plays a significant role in chemical equilibrium in the melt. X-ray diffraction measurements indicate that a higher Eu2+ fraction leads to a BaCl2 phase transition from hexagonal to orthorhombic structure at a lower temperature.

  14. Structural properties of fluorozirconate-based glass ceramics doped with multivalent europium

    SciTech Connect

    Passlick, C.; Mueller, O.; Luetzenkirchen-Hecht, D.; Frahm, R.; Johnson, J. A.; Schweizer, S.

    2011-12-01

    The structure/property relationships of fluorochlorozirconate glass ceramics as a function of divalent and trivalent europium (Eu) co-doping and thermal processing have been investigated; the influence of doping ratio on the formation of barium chloride (BaCl{sub 2}) nanocrystals therein was elucidated. X-ray absorption near-edge structure spectroscopy shows that the post-thermal annealing changes the Eu valence of the as-poured glass slightly, but during the melting process Eu{sup 3+} is more strongly reduced to Eu{sup 2+}, in particular, when doped as a chloride instead of fluoride compound. The Eu{sup 2+}-to-Eu{sup 3+} doping ratio also plays a significant role in chemical equilibrium in the melt. X-ray diffraction measurements indicate that a higher Eu{sup 2+} fraction leads to a BaCl{sub 2} phase transition from hexagonal to orthorhombic structure at a lower temperature.

  15. Effect of UV exposure on photochromic glasses doped with transition metal oxides

    NASA Astrophysics Data System (ADS)

    El-Zaiat, S. Y.; Medhat, M.; Omar, Mona F.; Shirif, Marwa A.

    2016-07-01

    Silver halide photochromic glasses doped with one of the transition metal oxides, (Ti O2), (CoO),(Cr2 O3) are prepared using the melt quench technique. Glass samples are exposed to a UV source for 20 min. Spectral reflectance and transmittance at normal incidence of the prepared glasses are recorded before and after UV exposure with a double beam spectrophotometer in the spectral range 200-2500 nm. Dispersion parameters such as: single oscillator energy, dispersion energy and Abbe's number are deduced and compared. Absorption dispersion parameters, like optical energy gap for direct and indirect transitions, Urbach energy and steepness parameter, are deduced for the different glass prepared. Reflection loss, molar refractivity and electronic polarizability are deduced and compared. The effect of UV light exposure of these glasses on transmittance, reflectance, the linear and the predicted nonlinear optical parameters are investigated and discussed for the three transition metals. Nonlinear parameters increase in the three glass samples after UV exposure.

  16. Laser irradiation in Nd{sup 3+} doped strontium barium niobate glass

    SciTech Connect

    Haro-Gonzalez, P.; Martin, I. R.; Arbelo-Jorge, E.; Gonzalez-Perez, S.; Caceres, J. M.; Nunez, P.

    2008-07-01

    A local nanocrystalline formation in a neodymium doped strontium barium niobate (SBN) glass has been obtained under argon laser irradiation. The intense emission around 880 nm, originated from the {sup 4}F{sub 3/2} ({sup 4}F{sub 5/2}) thermalized level when the glass structure changes to a glass ceramic structure due to the irradiation of the laser beam, has been studied. The intensities and lifetimes change from this level inside and outside the irradiated area made by the laser excitation. They have been analyzed and demonstrated that the desvitrification process has been successfully achieved. These results confirm that nanocrystals of SBN have been created by the laser action confirming that the transition from glass to glass ceramic has been completed. These results are in agreement with the emission properties of nanocrystals of the bulk glass ceramic sample. The present study also suggests that the SBN nanocrystal has a potential application as temperature detector.

  17. Active waveguides written by femtosecond laser irradiation in an erbium-doped phospho-tellurite glass.

    PubMed

    Fernandez, T Toney; Della Valle, G; Osellame, R; Jose, G; Chiodo, N; Jha, A; Laporta, P

    2008-09-15

    We report on fs-laser micromachining of active waveguides in a new erbium-doped phospho-tellurite glass by means of a compact cavity-dumped Yb-based writing system. The spectroscopic properties of the glass were investigated, and the fs-laser written waveguides were characterized in terms of passive as well as active performance. In particular, internal gain was demonstrated in the whole C+L band of optical communications (1530- 1610 nm).

  18. Luminescence properties of Tb(3+)-doped borosilicate scintillating glass under UV excitation.

    PubMed

    Zuo, Chenggang; Zhou, Zhihua; Zhu, Ligang; Xiao, Anguo; Chen, Yuandao; Zhang, Xiangyang; Zhuang, Yongbing; Li, Xiaoyang; Ge, Qizhi

    2015-08-01

    Transparent Li₂O-BaO-La₂O₃-Al₂O₃-B₂O₃-SiO₂ glasses doped with Tb(3+) ion were prepared by high temperature melting method. Luminescence properties of Tb(3+)-doped borosilicate glasses have been investigated by transmission, excitation, emission and luminescence decay measurements. The transmission spectrum shows the glass has good transmittance in the visible region. Under the 236 nm UV excitation the intense green emission from (5)D₄ level is observed in Tb(3+)-doped borosilicate glass, comparable in intensity to the violet-blue emission starting from the (5)D₃ level. The green emission intensity of Tb(3+) ion firstly increases and then decreases with the decreasing B₂O₃/SiO₂ ratio in glass matrix. (5)D₄→(7)FJ (J=6, 5, 4 and 3) transitions of Tb(3+) ion in borosilicate glass are greatly enhanced with increasing concentration of Tb(3+) through the cross relaxation [Tb(3+) ((5)D₃)+Tb(3+) ((7)F6)→Tb(3+) ((5)D₄)+Tb(3+) ((7)F₀)] between two Tb(3+) ions. Luminescence decay time of 2.13 ms is obtained for the emission transitions starting from (5)D₄ level in 2.5Li₂O-20BaO-20La₂O₃-2.5Al₂O₃-20B₂O₃-35SiO₂-0.5Tb₄O₇ glass. The results show that Tb(3+)-doped borosilicate glasses would be potential candidates for scintillating material for static X-ray imaging.

  19. Synthesis and optical properties of CsC1-doped gallium-sodium-sulfide glasses

    SciTech Connect

    Hehlen, Markus P; Bennett, Bryan L; Williams, Darrick J; Muenchausen, Ross E; Castro, Alonso; Tornga, Stephanie C

    2009-01-01

    Ga{sub 2}S{sub 3}-Na{sub 2}S (GNS) glasses doped with CsCl were synthesized in open crucibles under inert atmosphere. The evaporative loss of CsCl during glass melting was measured by energy dispersive X-ray spectroscopy and corrected for by biasing the CsCl concentration in the mixture of starting materials to obtain glasses with accurately controlled stoichiometry. Glass transition temperatures, refractive index dispersions, and band edge energies were measured for four GNS:CsCl glasses, and the respective values were found to significantly improve over earlier studies that did not mitigate CsCl evaporative losses. The refractive index dispersion measurements indicate that the Cs{sup +} and Cl{sup -} radii are 16% larger in GNS:CsCl glass than in bulk crystalline CsCl. The band edge energy increases from 2.97 eV in GNS glass to 3.32 eV in GNS glass doped with 20 mol% CsCl as a result of introducing Cl{sup -} ions having a large optical electronegativity. The large bandgap of 3.32 eV and the low (450 cm{sup -1}) phonon energy make GNS:20%CsCl an attractive host material for rare-earth ions with radiative transitions in the near ultra-violet, visible, and near-infrared spectral regions.

  20. Radiation hardening in sol-gel derived Er{sup 3+}-doped silica glasses

    SciTech Connect

    Hari Babu, B. E-mail: matthieu.lancry@u-psud.fr; León Pichel, Mónica; Ollier, Nadège; El Hamzaoui, Hicham; Bigot, Laurent; Savelii, Inna; Bouazaoui, Mohamed; Poumellec, Bertrand; Lancry, Matthieu E-mail: matthieu.lancry@u-psud.fr; Ibarra, Angel

    2015-09-28

    The aim of the present paper is to report the effect of radiation on the Er{sup 3+}-doped sol-gel silica glasses. A possible application of these sol-gel glasses could be their use in harsh radiation environments. The sol-gel glasses are fabricated by densification of erbium salt-soaked nanoporous silica xerogels through polymeric sol-gel technique. The radiation-induced attenuation of Er{sup 3+}-doped sol-gel silica is found to increase with erbium content. Electron paramagnetic resonance studies reveal the presence of E′{sub δ} point defects. This happens in the sol-gel aluminum-silica glass after an exposure to γ-rays (kGy) and in sol-gel silica glass after an exposure to electrons (MGy). The concentration levels of these point defects are much lower in γ-ray irradiated sol-gel silica glasses. When the samples are co-doped with Al, the exposure to γ-ray radiation causes a possible reduction of the erbium valence from Er{sup 3+} to Er{sup 2+} ions. This process occurs in association with the formation of aluminum oxygen hole centers and different intrinsic point defects.

  1. Cubic to tetragonal phase transition of Tm3+ doped nanocrystals in oxyfluoride glass ceramics

    NASA Astrophysics Data System (ADS)

    Li, Yiming; Zhao, Lijuan; Fu, Yuting; Shi, Yahui; Zhang, Xiaoyu; Yu, Hua

    2016-02-01

    Tm3+ ions doped β-PbF2 nanocrystals in oxyfluoride glass ceramics with different doping concentrations and thermal temperatures are prepared by a traditional melt-quenching and thermal treatment method to investigate the structure and the phase transition of Tm3+ doped nanocrystals. The structures are characterized by X-ray diffraction Rietveld analysis and confirmed with numerical simulation. The phase transitions are proved further by the emission spectra. Both of the doping concentration and thermal temperature can induce an Oh to D4h site symmetry distortion and a cubic to tetragonal phase transition. The luminescence of Tm3+ doped nanocrystals at 800 nm was modulated by the phase transition of the surrounding crystal field.

  2. Thermoluminescence responses of photon- and electron-irradiated lithium potassium borate co-doped with Cu+Mg or Ti+Mg.

    PubMed

    Alajerami, Y S M; Hashim, S; Ramli, A T; Saleh, M A; Saripan, M I; Alzimami, K; Min Ung, Ngie

    2013-08-01

    New glasses Li2CO3-K2CO3-H3BO3 (LKB) co-doped with CuO and MgO, or with TiO2 and MgO, were synthesized by the chemical quenching technique. The thermoluminescence (TL) responses of LKB:Cu,Mg and LKB:Ti,Mg irradiated with 6 MV photons or 6 MeV electrons were compared in the dose range 0.5-4.0 Gy. The standard commercial dosimeter LiF:Mg,Ti (TLD-100) was used to calibrate the TL reader and as a reference in comparison of the TL properties of the new materials. The dependence of the responses of the new materials on (60)Co dose is linear in the range of 1-1000 Gy. The TL yields of both of the co-doped glasses and TLD-100 are greater for electron irradiation than for photon irradiation. The TL sensitivity of LKB:Ti,Mg is 1.3 times higher than the sensitivity of LKB:Cu,Mg and 12 times less than the sensitivity of TLD-100. The new TL dosimetric materials have low effective atomic numbers, good linearity of the dose responses, excellent signal reproducibility, and a simple glow curve structure. This combination of properties makes them suitable for radiation dosimetry.

  3. Liquid phase sintering of 20Bi(Zn0.5Ti0.5)O 3-80BaTiO3 dielectrics with bismuth-zinc-borate and bismuth borosilicate glasses

    NASA Astrophysics Data System (ADS)

    Shahin, David I.

    Dielectrics in the Bi(Zn0.5Ti0.5)O3-BaTiO 3 system (specifically 20BZT-80BT, in mol%) are promising candidates for high energy density capacitor applications due to broad temperature-dependent dielectric constant maxima and a relatively field-independent permittivity. Bulk samples require sintering temperatures of greater than 1180°C to reach useful densities. Due to incompatibility of Bi with low-pO2 processing, BZT-BT-based multilayer capacitors must utilize noble metal electrodes that resist oxidation during sintering. Sintering temperatures must be reduced to allow use of less expensive electrode materials (Cu, etc.). This work studies the reduced temperature sintering behavior and dielectric properties of BZT-BT sintered with 30Bi2O3-30ZnO-40B 2O3 and 50Bi2O3-25B2O 3-25SiO2 (mol%) liquid phase formers. Dielectrics sintered with 1v% borate additions and 5v% additions of either the borate or borosilicate achieved relative densities greater than 95% after sintering at 1000°C for four hours. All compositions retained the relaxor behavior exhibited by pure 20BZT-80BT. Increased borate additions led to greater dielectric constant reductions, while increased borosilicate additions yielded no clear trend in the dielectric constant reduction. Energy densities were estimated between 0.3-0.5 J/cm3; smaller glass additions typically led to larger energy densities. Dielectrics sintered with 1v% borate additions are of interest due to their high relative densities (approx. 96%) and energy densities of approximately 0.5 J/cm3 under 100kV/cm electric fields. Studies of BZT-BT/glass interfaces revealed the formation of crystalline interfacial layers less than 10 microns thick. The borate formed a bismuth titanate phase (likely Bi4Ti3O12) during heating to 700°C, whereas the borosilicate formed a barium silicate phase (likely BaSiO3) during processing to 800°C. Similar phases are expected to be present in the liquid phase sintered dielectrics and likely affect the BZT

  4. Energy transfer kinetics in oxy-fluoride glass and glass-ceramics doped with rare-earth ions

    SciTech Connect

    Sontakke, Atul D.; Annapurna, K.

    2012-07-01

    An investigation of donor-acceptor energy transfer kinetics in dual rare earths doped precursor oxy-fluoride glass and its glass-ceramics containing NaYF{sub 4} nano-crystals is reported here, using three different donor-acceptor ion combinations such as Nd-Yb, Yb-Dy, and Nd-Dy. The precipitation of NaYF{sub 4} nano-crystals in host glass matrix under controlled post heat treatment of precursor oxy-fluoride glasses has been confirmed from XRD, FESEM, and transmission electron microscope (TEM) analysis. Further, the incorporation of dopant ions inside fluoride nano-crystals has been established through optical absorption and TEM-EDX analysis. The noticed decreasing trend in donor to acceptor energy transfer efficiency from precursor glass to glass-ceramics in all three combinations have been explained based on the structural rearrangements that occurred during the heat treatment process. The reduced coupling phonon energy for the dopant ions due to fluoride environment and its influence on the overall phonon assisted contribution in energy transfer process has been illustrated. Additionally, realization of a correlated distribution of dopant ions causing clustering inside nano-crystals has also been reported.

  5. Waveguides in Ni-doped glass and glass-ceramic written with a 1 kHz femtosecond laser

    NASA Astrophysics Data System (ADS)

    Hughes, M. A.; Homewood, K. P.; Curry, R. J.; Ohishi, Y.; Suzuki, T.

    2014-07-01

    We report waveguides in Ni-doped Li2O-Ga2O3-SiO2 (Ni:LGS) glass and glass-ceramic (GC) fabricated with a femtosecond (fs) laser with repetition rate of 1 kHz. When the glass is annealed to form a GC, the waveguides are erased. However, in the GC the waveguides are not erased by annealing. In Ni:LGS GC a 415 nm absorption band was created by fs laser waveguide writing due to the creation of Ni nanoparticles with an estimated diameter of a few nm. Raman and photoluminescence spectra of the bulk and waveguide structures were indistinguishable; however, fluorescence decay profiles indicated more long lifetime components in the waveguide compared to the bulk.

  6. Effects of rare-earth doping on femtosecond laser waveguide writing in zinc polyphosphate glass

    SciTech Connect

    Fletcher, Luke B.; Witcher, Jon J.; Troy, Neil; Krol, Denise M.; Reis, Signo T.; Brow, Richard K.

    2012-07-15

    We have investigated waveguide writing in Er-Yb doped zinc polyphosphate glass using a femtosecond laser with a repetition rate of 1 KHz. We find that fabrication of good waveguides requires a glass composition with an O/P ratio of 3.25. The dependence on laser writing parameters including laser fluence, focusing conditions, and scan speed is reported. Waveguide properties together with absorption and emission data indicate that these glasses can be used for the fabrication of compact, high gain amplifying devices.

  7. Electrical and mechanical properties of ZnO doped silver-molybdate glass-nanocomposite system

    NASA Astrophysics Data System (ADS)

    Kundu, Ranadip; Roy, Debasish; Bhattacharya, Sanjib

    2016-05-01

    Zno doped silver-molybdate glass-nanocomposites, 0.3 Ag2O - 0.7 [0.075 ZnO - 0.925 MoO3] have been prepared by melt-quenching method. Ionic conductivity of these glass-nanocomposites has been measured in wide temperature and frequency windows. Vicker's hardness methods have been employed to study micro-hardness of the as-prepared samples. Heat-treated counterparts for this glass-nanocomposites system has been analyzed in different temperature to observe the changes in conductivity as well as micro-hardness for that system.

  8. The IR emitting centers in Bi-doped Mg-Al-Si oxide glasses

    NASA Astrophysics Data System (ADS)

    Denker, B.; Galagan, B.; Osiko, V.; Shulman, I.; Sverchkov, S.; Dianov, E.

    2009-05-01

    The properties of IR emission centers are investigated in Bi-doped Mg-Al-silicate glasses having moderate melting temperatures to be fabricated by routine melting in alumina crucibles. The quadratic concentration dependence of absorption in the visible range indicates that the considered optical centers can be Bi2 dimers forming in a balanced chemical reaction in the glass melt. Their formation enthalpy is evaluated from their concentration variations with the synthesis temperature. The high (up to 85% at low concentrations) luminescence quantum yield and wide emission spectrum makes this glass a promising material for tunable lasers.

  9. 1.8 μm emission of highly thulium doped fluorophosphate glasses

    NASA Astrophysics Data System (ADS)

    Tian, Ying; Xu, Rongrong; Zhang, Liyan; Hu, Lili; Zhang, Junjie

    2010-10-01

    A new type of fluorophosphate glasses with high thulium doping concentration (up to 10 mol % Tm3+) is investigated. The intensive 1.8 μm fluorescence is demonstrated with lower concentration quenching. On the basis of the measured Raman spectroscopy, it is revealed that the glass structure will be changed when adding Tm3+ ions into fluorophosphate glasses. Besides, the Judd-Ofelt parameters and radiative properties are calculated and discussed based on Judd-Ofelt theory. And the absorption and emission cross-sections of F34→H36 transition are also calculated by using McCumber and Beer-Lambert theories.

  10. Cooperative luminescence and absorption in ytterbium doped aluminosilicate glass optical fibres and preforms

    NASA Astrophysics Data System (ADS)

    Ryan, Tom G.; Jackson, Stuart D.

    2007-05-01

    The cooperative luminescence and absorption properties of Yb 3+ doped aluminosilicate glass optical fibres and preforms are investigated in detail. In accordance with previous investigations, both the visible cooperative luminescence and the infrared luminescence decay measurements have been resolved into a single exponential decay component. We show that for a glass with similar Yb 3+ dopant concentration but more Al 3+, the glass emits less visible luminescence. Absorption loss measurements completed on fibre samples revealed a broad absorption in the 350-500 nm range, which we propose is due to a combination of Yb 2+ absorption and cooperative absorption from Yb 3+ ion pairs.

  11. Effects of rare-earth doping on femtosecond laser waveguide writing in zinc polyphosphate glass

    NASA Astrophysics Data System (ADS)

    Fletcher, Luke B.; Witcher, Jon J.; Troy, Neil; Reis, Signo T.; Brow, Richard K.; Krol, Denise M.

    2012-07-01

    We have investigated waveguide writing in Er-Yb doped zinc polyphosphate glass using a femtosecond laser with a repetition rate of 1 KHz. We find that fabrication of good waveguides requires a glass composition with an O/P ratio of 3.25. The dependence on laser writing parameters including laser fluence, focusing conditions, and scan speed is reported. Waveguide properties together with absorption and emission data indicate that these glasses can be used for the fabrication of compact, high gain amplifying devices.

  12. Line patterning of (Sr,Ba)Nb{sub 2}O{sub 6} crystals in borate glasses by transition metal atom heat processing

    SciTech Connect

    Sato, M.; Honma, T.; Benino, Y.; Komatsu, T.

    2007-09-15

    Some NiO-doped Bi{sub 2}O{sub 3},La{sub 2}O{sub 3}-SrO-BaO-Nb{sub 2}O{sub 5}-B{sub 2}O{sub 3} glasses giving the formation of strontium barium niobate Sr{sub 0.5}Ba{sub 0.5}Nb{sub 2}O{sub 6} (SBN) crystals with a tetragonal tungsten-bronze structure through conventional crystallization in an electric furnace have been developed, and SBN crystal lines have been patterned on the glass surface by heat-assisted (250-300 deg. C) laser irradiation and scanning of continuous-wave Nd:YAG laser (wavelength: 1064 nm). The surface morphology and the quality of SBN crystal lines are examined from measurements of confocal scanning laser micrographs and polarized micro-Raman scattering spectra. The surface morphology of SBN crystal lines changes from periodic bump structures to homogeneous structures, depending on laser scanning conditions. It is suggested that the line patterned at the laser irradiation condition of laser power P=1 W and of laser scanning speed S=1 {mu}m/s in 2NiO-4La{sub 2}O{sub 3}-16SrO-16BaO-32Nb{sub 2}O{sub 5}-30B{sub 2}O{sub 3} glass has a possibility of the orientation of SBN crystals along the laser scanning direction. The present study demonstrates that the transition metal atom heat processing (i.e., a combination of cw Nd:YAG laser and Ni{sup 2+} ions) is a novel technique for spatially selected crystallization of SBN crystals in glass. - Graphical abstract: This figure shows the polarization optical (a) and confocal scanning laser (b) micrographs for the sample obtained by heat-assisted (300 deg. C) Nd:YAG laser irradiation with a laser power of P=1 W and laser scanning speed of S=1 {mu}m/s in Glass C. The figure demonstrates that the transition metal atom heat processing (i.e., a combination of cw Nd:YAG laser and Ni{sup 2+} ions) is a novel technique for spatially selected crystallization of SBN crystals in glass.

  13. Influence of Cu doping in borosilicate bioactive glass and the properties of its derived scaffolds.

    PubMed

    Wang, Hui; Zhao, Shichang; Xiao, Wei; Xue, Jingzhe; Shen, Youqu; Zhou, Jie; Huang, Wenhai; Rahaman, Mohamed N; Zhang, Changqing; Wang, Deping

    2016-01-01

    Copper doped borosilicate glasses (BG-Cu) were studied by means of FT-IR, Raman, UV-vis and NMR spectroscopies to investigate the changes that appeared in the structure of borosilicate glass matrix by doping copper ions. Micro-fil and immunohistochemistry analysis were applied to study the angiogenesis of its derived scaffolds in vivo. Results indicated that the Cu ions significantly increased the B-O bond of BO4 groups at 980 cm(-1), while they decrease that of BO2O(-) groups at 1440-1470 cm(-1) as shown by Raman spectra. A negative shift was observed from (11)B and (29)Si NMR spectra. The (11)B NMR spectra exhibited a clear transformation from BO3 into BO4 groups, caused by the agglutination effect of the Cu ions and the charge balance of the agglomerate in the glass network, leading to a more stable glass network and lower ions release rate in the degradation process. Furthermore, the BG-Cu scaffolds significantly enhanced blood vessel formation in rat calvarial defects at 8 weeks post-implantation. Generally, it suggested that the introduction of Cu into borosilicate glass endowed glass and its derived scaffolds with good properties, and the cooperation of Cu with bioactive glass may pave a new way for tissue engineering.

  14. Photoluminescence in rare-earth doped As2S3 glasses

    NASA Astrophysics Data System (ADS)

    Iovu, Mihai S.; Andriesh, Andrei M.; Culeac, Ion P.

    2005-02-01

    Chalcogenide glasses doped with various rare-earth ions are extensively studied as potential materials for fiber optic amplifiers operating at 1.3 and 1.5 μm telecommunication windows. The experimental results on optical absorption and photoluminescence of arsenic sulfide glasses and optical fibers doped with rare-earth elements (Pr3+, Sm3+, Er3+ and Dy3+) are presented. Near the absorption edge the rare-earth impurities affect strongly the slope and the magnitude of the week absorption tail. Fluorescence spectra of bulk samples and optical fibers of arsenic sulfide doped with different concentrations of Pr3+ and Dy3+ indicate on the presence of luminescent band located around 1.3 and 1.5 μm. These bands correspond to the electron transitions from the discrete levels (6F7/2&rarr:6H13/2 and 6F5/2&rarr6H11/2 for Dy3+ and 1G4/1&rarr3H6 and 3F3&rarr3H4 for Pr3+, respectively), and which confirmed the presence of trivalent rare-earth ions in the glass matrix. The observed effects of rare-earth dopants on the As2S3 glass are discussed in connection with the expected behavior of the impurities in the glass.

  15. Thermal, optical and structural properties of Dy3+ doped sodium aluminophosphate glasses

    NASA Astrophysics Data System (ADS)

    Kaur, Manpreet; Singh, Anupinder; Thakur, Vanita; Singh, Lakhwant

    2016-03-01

    Trivalent Dysprosium doped sodium aluminophosphate glasses with composition 50P2O5-10Al2O3-(20-x)Na2O-20CaO-xDy2O3 (x varying from 0 to 5 mol%) were prepared by melt quench technique. The density of the prepared samples was measured using Archimedes principle and various physical properties like molar volume, rare earth ion concentration, polaron radius, inter nuclear distance and field strength were calculated using different formulae. The differential scanning calorimetry (DSC) was carried out to study the thermal stability of prepared glasses. The UV Visible absorption spectra of the dysprosium doped glasses were found to be comprised of ten absorption bands which correspond to transitions from ground state 6H15/2 to various excited states. The indirect optical band gap energy of the samples was calculated by Tauc's plot and the optical energy was found to be attenuated with Dy3+ ions. The photoluminescence spectrum revealed that Dy3+ doped aluminophosphate glasses have strong emission bands in the visible region. A blue emission band centred at 486 nm, a bright yellow band centred at 575 nm and a weak red band centred at 668 nm were observed in the emission spectrum due to excitation at 352 nm wavelength. Both FTIR and Raman spectra assert slight structural changes induced in the host glass network with Dy3+ ions.

  16. Structural studies of lithium boro tellurite glasses doped with praseodymium and samarium oxides

    SciTech Connect

    Damas, Pedro; Coelho, João; Hungerford, Graham; Hussain, N. Sooraj

    2012-11-15

    Graphical abstract: [TeO{sub 4}] trigonal bipyramid structural unit, which is formed by two unequivalent pair of oxygen atoms: two equatorial oxygens (O{sub eq}) and two axial oxygens (O{sub ax}). Highlights: ► Pr{sup 3+} and Sm{sup 3+} doped LBT glasses have been prepared and characterized. ► LBT glasses present normal surfaces without metallic clusters. ► Raman spectra revealed the network modifying behaviour of dopant ions. -- Abstract: This paper reports the preparation and structural studies of praseodymium and samarium (0.5, 2 and 4 mol%) oxide doped lithium boro tellurite glasses. These materials were prepared by the quenching technique in a ceramic crucible at 950 °C. Structural characterization was performed by Raman spectroscopy, Scanning Electron Microscopy and Energy Dispersive X-ray spectroscopy techniques. Results from Raman analysis are in good agreement with those reported in the literature, revealing a normal glass structure for the host material. Understanding on how the glasses internal structure changed when the doping concentration increases was also assessed.

  17. The microstructure of erbium-ytterbium co-doped oxyfluoride glass-ceramic optical fibers

    NASA Astrophysics Data System (ADS)

    Augustyn, Elżbieta; Żelechower, Michał; Stróż, Danuta; Chrapoński, Jacek

    2012-04-01

    Oxyfluoride transparent glass-ceramics combine some features of glasses (easier shaping or lower than single crystals cost of fabrication) and some advantages of rare-earth doped single crystals (narrow absorption/emission lines and longer lifetimes of luminescent levels). Since the material seems to be promising candidate for efficient fiber amplifiers, the manufacturing as well as structural and optical examination of the oxyfluoride glass-ceramic fibers doped with rare-earth ions seems to be a serious challenge. In the first stage oxyfluoride glasses of the following compositions 48SiO2-11Al2O3-7Na2CO3-10CaO-10PbO-11PbF2-3ErF3 and 48SiO2-11Al2O3-7Na2CO3-10CaO-10PbO-10PbF2-3YbF3-1ErF3 (in molar%) were fabricated from high purity commercial chemicals (Sigma-Aldrich). The fabricated glass preforms were drawn into glass fibers using the mini-tower. Finally, the transparent Er3+ doped and Er3+/Yb3+ co-doped oxyfluoride glass-ceramic fibers were obtained by controlled heat treatment of glass fibers. The preceding differential thermal analysis (DTA) studies allowed estimating both the fiber drawing temperature and the controlled crystallization temperature of glass fibers. X-ray diffraction examination (XRD) at each stage of the glass-ceramic fibers fabrication confirmed the undesirable crystallization of preforms and glass fibers has been avoided. The fibers shown their mixed amorphous-crystalline microstructure with nano-crystals of size even below 10 nm distributed in the glassy host. The crystal structure of the grown nano-crystals has been determined by XRD and confirmed by electron diffraction (SAED). Results obtained by both techniques seem to be compatible: Er3FO10Si3 (monoclinic; ICSD 92512), Pb5Al3F19 (triclinic; ICSD 91325) and Er4F2O11Si3 (triclinic; ICSD 51510) against to initially expected PbF2 crystals.

  18. Charge transport in tri-p-tolylamine doped trinaphthalylbenzene glass

    NASA Astrophysics Data System (ADS)

    Lin, Liang-Bih; O'Reilly, James M.; Magin, Edward H.; Weiss, David S.; Jenekhe, Samson A.

    2000-09-01

    The charge transport properties of tri-p-tolylamine (TTA) doped trinaphthalylbenzene have been measured as a function of electric field and temperature. The charge mobilities of the composite are comparable to but somewhat lower than that of TTA doped polystyrene, a nonpolar polymeric host, at similar weight fractions. We suggest that the difference is due to inhomogeneity between the host and the dopant. The results suggest that, similar to polymer hosts in molecularly doped polymers, the molecular host only functions as an inert diluter and does not directly participate in the charge transport manifold. The results also substantiate the importance of molecular packing to charge hopping in disordered organic materials. The charge mobility data are analyzed with a disorder model due to Bässler and coworkers and a recently modified expression due to Novikov and coworkers [Phys. Rev. Lett. 81, 4472 (1998)]. Both models provide adequate descriptions of charge transport in organic amorphous materials.

  19. Luminescent properties of Bi-doped boro-alumino-phosphate glasses

    NASA Astrophysics Data System (ADS)

    Denker, B.; Galagan, B.; Osiko, V.; Sverchkov, S.; Dianov, E.

    2007-03-01

    A new Bi-doped boro-alumino-phosphate glass (BAP) composition was developed. Absorption and emission spectra and luminescence decay kinetics were investigated. The emission spectrum consists of two wide bands in the visible (0.6 0.8 μm) and near-infrared (˜1.0 1.5 μm) ranges. The luminescence decay curve investigation has revealed a complicated behavior dependent on both excitation and registration wavelengths. In contrast to earlier investigated Bi-doped glasses, Bi:BAP has good technological properties and can be easily scaled. This makes the developed glass composition interesting for broadband tunable (˜1.0 1.5 μm) lasers and amplifiers.

  20. Optical properties of Ce3+ doped fluorophosphates scintillation glasses

    NASA Astrophysics Data System (ADS)

    Yao, Yongxin; Liu, Liwan; Zhang, Yu; Chen, Danping; Fang, Yongzheng; Zhao, Guoying

    2016-01-01

    Fluorophosphates (P2O5-BaO-BaF2-Al2O3-Gd2O3-Ce2O3) glasses with different Gd2O3 and BaF2 concentrations have been prepared by a melt quenching method. The effect of Gd2O3 and BaF2 on the glass performance including the density, absorption as well as luminescence properties under both ultraviolet (UV) and X-ray excitation was studied systematically. Energy transfer from Gd3+ to Ce3+ plays an important role in the scintillation mechanism of these glasses and the optimum concentration of Gd2O3 is found to be approximately 3 mol%. The highest integrated light emission intensity of these glass samples excited by X-ray is 25% of BGO and the decay time constants are in the range of 25-35 ns, much shorter than the 300 ns decay time of BGO. Meanwhile, replacing lighter compound BaO with the BaF2 can increase the density of the glasses and also improve the light yield.

  1. Bioactive glass in tissue engineering

    PubMed Central

    Rahaman, Mohamed N.; Day, Delbert E.; Bal, B. Sonny; Fu, Qiang; Jung, Steven B.; Bonewald, Lynda F.; Tomsia, Antoni P.

    2011-01-01

    This review focuses on recent advances in the development and use of bioactive glass for tissue engineering applications. Despite its inherent brittleness, bioactive glass has several appealing characteristics as a scaffold material for bone tissue engineering. New bioactive glasses based on borate and borosilicate compositions have shown the ability to enhance new bone formation when compared to silicate bioactive glass. Borate-based bioactive glasses also have controllable degradation rates, so the degradation of the bioactive glass implant can be more closely matched to the rate of new bone formation. Bioactive glasses can be doped with trace quantities of elements such as Cu, Zn and Sr, which are known to be beneficial for healthy bone growth. In addition to the new bioactive glasses, recent advances in biomaterials processing have resulted in the creation of scaffold architectures with a range of mechanical properties suitable for the substitution of loaded as well as non-loaded bone. While bioactive glass has been extensively investigated for bone repair, there has been relatively little research on the application of bioactive glass to the repair of soft tissues. However, recent work has shown the ability of bioactive glass to promote angiogenesis, which is critical to numerous applications in tissue regeneration, such as neovascularization for bone regeneration and the healing of soft tissue wounds. Bioactive glass has also been shown to enhance neocartilage formation during in vitro culture of chondrocyte-seeded hydrogels, and to serve as a subchondral substrate for tissue-engineered osteochondral constructs. Methods used to manipulate the structure and performance of bioactive glass in these tissue engineering applications are analyzed. PMID:21421084

  2. Bioactive glass in tissue engineering.

    PubMed

    Rahaman, Mohamed N; Day, Delbert E; Bal, B Sonny; Fu, Qiang; Jung, Steven B; Bonewald, Lynda F; Tomsia, Antoni P

    2011-06-01

    This review focuses on recent advances in the development and use of bioactive glass for tissue engineering applications. Despite its inherent brittleness, bioactive glass has several appealing characteristics as a scaffold material for bone tissue engineering. New bioactive glasses based on borate and borosilicate compositions have shown the ability to enhance new bone formation when compared to silicate bioactive glass. Borate-based bioactive glasses also have controllable degradation rates, so the degradation of the bioactive glass implant can be more closely matched to the rate of new bone formation. Bioactive glasses can be doped with trace quantities of elements such as Cu, Zn and Sr, which are known to be beneficial for healthy bone growth. In addition to the new bioactive glasses, recent advances in biomaterials processing have resulted in the creation of scaffold architectures with a range of mechanical properties suitable for the substitution of loaded as well as non-loaded bone. While bioactive glass has been extensively investigated for bone repair, there has been relatively little research on the application of bioactive glass to the repair of soft tissues. However, recent work has shown the ability of bioactive glass to promote angiogenesis, which is critical to numerous applications in tissue regeneration, such as neovascularization for bone regeneration and the healing of soft tissue wounds. Bioactive glass has also been shown to enhance neocartilage formation during in vitro culture of chondrocyte-seeded hydrogels, and to serve as a subchondral substrate for tissue-engineered osteochondral constructs. Methods used to manipulate the structure and performance of bioactive glass in these tissue engineering applications are analyzed.

  3. Structural and optical study on antimony-silicate glasses doped with thulium ions.

    PubMed

    Dorosz, D; Zmojda, J; Kochanowicz, M; Miluski, P; Jelen, P; Sitarz, M

    2015-01-01

    Structural, spectroscopic and thermal properties of SiO₂-Al₂O₃-Sb₂O₃-Na₂O glass system doped with 0.2 mol% Tm₂O₃ have been presented. Synthesis of antimony-silicate glasses with relatively low phonon energy (600 cm(-1), which implicates a small non-radiative decay rate) was performed by conventional high-temperature melt-quenching methods. The effect of SiO₂/Sb₂O₃ ratio in fabricated Tm(3+) doped glass on thermal, structural and luminescence properties was investigated. On the basis of structural investigations decomposition of absorption bands in the infrared FTIR region was performed, thus determining that antimony ions are the only glass-forming ions, setting up the lattice of fabricated glasses. Luminescence band at the wavelength of 1.8 μm corresponding to (3)F₄→(3)H₆ transition in thulium ions was obtained under 795 nm laser pumping. It was observed that combination of relatively low phonon energy and greater separation of optically active centers in the fabricated glasses influenced in decreasing the luminescence intensity at 1800 nm.

  4. Electrophoretic Deposition of Chitosan/45S5 Bioactive Glass Composite Coatings Doped with Zn and Sr

    PubMed Central

    Miola, Marta; Verné, Enrica; Ciraldo, Francesca Elisa; Cordero-Arias, Luis; Boccaccini, Aldo R.

    2015-01-01

    In this research work, the original 45S5 bioactive glass was modified by introducing zinc and/or strontium oxide (6 mol%) in place of calcium oxide. Sr was added for its ability to stimulate bone formation and Zn for its role in bone metabolism, antibacterial properties, and anti-inflammatory effect. The glasses were produced by means of melting and quenching process. SEM and XRD analyses evidenced that Zr and Sr introduction did not modify the glass structure and morphology while compositional analysis (EDS) demonstrated the effective incorporation of these elements in the glass network. Bioactivity test in simulated body fluid (SBF) up to 1 month evidenced a reduced bioactivity kinetics for Zn-doped glasses. Doped glasses were combined with chitosan to produce organic/inorganic composite coatings on stainless steel AISI 316L by electrophoretic deposition (EPD). Two EPD processes were considered for coating development, namely direct current EPD (DC-EPD) and alternating current EPD (AC-EPD). The stability of the suspension was analyzed and the deposition parameters were optimized. Tape and bending tests demonstrated a good coating-substrate adhesion for coatings containing 45S5-Sr and 45S5-ZnSr glasses, whereas the adhesion to the substrate decreased by using 45S5-Zn glass. FTIR analyses demonstrated the composite nature of coatings and SEM observations indicated that glass particles were well integrated in the polymeric matrix, the coatings were fairly homogeneous and free of cracks; moreover, the AC-EPD technique provided better results than DC-EPD in terms of coating quality. SEM, XRD analyses, and Raman spectroscopy, performed after bioactivity test in SBF solution, confirmed the bioactive behavior of 45S5-Sr-containing coating while coatings containing Zn exhibited no hydroxyapatite formation. PMID:26539431

  5. Electrophoretic Deposition of Chitosan/45S5 Bioactive Glass Composite Coatings Doped with Zn and Sr.

    PubMed

    Miola, Marta; Verné, Enrica; Ciraldo, Francesca Elisa; Cordero-Arias, Luis; Boccaccini, Aldo R

    2015-01-01

    In this research work, the original 45S5 bioactive glass was modified by introducing zinc and/or strontium oxide (6 mol%) in place of calcium oxide. Sr was added for its ability to stimulate bone formation and Zn for its role in bone metabolism, antibacterial properties, and anti-inflammatory effect. The glasses were produced by means of melting and quenching process. SEM and XRD analyses evidenced that Zr and Sr introduction did not modify the glass structure and morphology while compositional analysis (EDS) demonstrated the effective incorporation of these elements in the glass network. Bioactivity test in simulated body fluid (SBF) up to 1 month evidenced a reduced bioactivity kinetics for Zn-doped glasses. Doped glasses were combined with chitosan to produce organic/inorganic composite coatings on stainless steel AISI 316L by electrophoretic deposition (EPD). Two EPD processes were considered for coating development, namely direct current EPD (DC-EPD) and alternating current EPD (AC-EPD). The stability of the suspension was analyzed and the deposition parameters were optimized. Tape and bending tests demonstrated a good coating-substrate adhesion for coatings containing 45S5-Sr and 45S5-ZnSr glasses, whereas the adhesion to the substrate decreased by using 45S5-Zn glass. FTIR analyses demonstrated the composite nature of coatings and SEM observations indicated that glass particles were well integrated in the polymeric matrix, the coatings were fairly homogeneous and free of cracks; moreover, the AC-EPD technique provided better results than DC-EPD in terms of coating quality. SEM, XRD analyses, and Raman spectroscopy, performed after bioactivity test in SBF solution, confirmed the bioactive behavior of 45S5-Sr-containing coating while coatings containing Zn exhibited no hydroxyapatite formation. PMID:26539431

  6. Nucleation and crystallization of Ca doped basaltic glass for the production of a glass-ceramic material

    NASA Astrophysics Data System (ADS)

    Tarrago, Mariona; Royo, Irene; Garcia-Valles, Maite; Martínez, Salvador

    2016-04-01

    Sewage sludge from wastewater treatment plants is a waste with a composition roughly similar to that of a basalt. It may contain potentially toxic elements that can be inertized by vitrification. Using a glass-ceramic process, these elements will be emplaced in newly formed mineral phases. Glass-ceramic production requires an accurate knowledge of the temperatures of nucleation (TN) and crystal growth of the corresponding minerals. This work arises from the study of the addition of ions to a basaltic matrix in order to establish a model of vitrification of sewage sludge. In this case a glass-ceramic is obtained from a glass made with a basalt that has been doped with 16% CaO. Two glasses which underwent different cooling processes have been produced and compared. The first was annealed at 650oC (AG) and the second was quenched (QG). The chemical composition of the glasses is SiO2 36.11 wt%, Al2O312.19 wt%, CaO 24.44 wt%, FeO 10.06 wt%, MgO 9.19 wt%, Na2O 2.28 wt%, TiO2 2.02 wt%, K2O 1.12 wt%, P2O5 0.46 wt%. Glass transition temperature obtained by dilatometry varies from 640 oC (AG) to 700 oC (QG). The temperatures of nucleation and crystal growth of the glass have been determined by Differential Thermal Analysis (DTA). The phases formed after these treatments were identified by X-Ray Diffraction. The temperatures of exothermic and endothermic peaks measured in the quenched glass are, in average, 10 oC higher than those found for the annealed glass. The exothermic peaks provide crystallization temperatures for different phases: a first event at 857 oC corresponds to the growth of magnetite, pyroxene and nepheline, whereas a second event at 1030 oC is due to the crystallization of melilite from the reaction between previous minerals and a remaining amorphous phase. The complete melting of this system occurs at 1201 oC. This glass has been nucleated inside the DTA furnace (500-850° C/3 hours) and then heated up to 1300 oC using the fraction between 400-500μm. TN

  7. Spectroscopic characteristics of chromium doped mullite glass-ceramics

    SciTech Connect

    Wojtowicz, A.J.; Meng, W.; Lempicki, A.; Beall, G.H.; Hall, D.W.; Chin, T.C.

    1988-06-01

    Characteristics of chromium doped mullite ceramics are discussed with reference to possible laser applications. Dominant features are attributed to large and inherent spectroscopic inhomogeneity of mullite. The spectroscopic data are analyzed using a generalized McCumber theory. The peak stimulated emission cross section is 0.54 x 10/sup -20/ cm/sup 2/. This, together with preliminary single-pass measurements, indicate that gain for mullite is about 2.6 times smaller than gain for alexandrite.

  8. EPR, optical absorption and luminescence studies of Cr3+-doped antimony phosphate glasses

    NASA Astrophysics Data System (ADS)

    De Vicente, F. S.; Santos, F. A.; Simões, B. S.; Dias, S. T.; Siu Li, M.

    2014-12-01

    Antimony phosphate glasses (SbPO) doped with 3 and 6 mol% of Cr3+ were studied by Electron Paramagnetic Resonance (EPR), UV-VIS optical absorption and luminescence spectroscopy. The EPR spectra of Cr3+-doped glasses showed two principal resonance signals with effective g values at g = 5.11 and g = 1.97. UV-VIS optical absorption spectra of SbPO:Cr3+ presented four characteristics bands at 457, 641, 675, and 705 nm related to the transitions from 4A2(F) to 4T1(F), 4T2(F), 2T1(G), and 2E(G), respectively, of Cr3+ ions in octahedral symmetry. Optical absorption spectra of SbPO:Cr3+ allowed evaluating the crystalline field Dq, Racah parameters (B and C) and Dq/B. The calculated value of Dq/B = 2.48 indicates that Cr3+ ions in SbPO glasses are in strong ligand field sites. The optical band gap for SbPO and SbPO:Cr3+ were evaluated from the UV optical absorption edges. Luminescence measurements of pure and Cr3+-doped glasses excited with 350 nm revealed weak emission bands from 400 to 600 nm due to the 3P1 → 1S0 electronic transition from Sb3+ ions. Cr3+-doped glasses excited with 415 nm presented Cr3+ characteristic luminescence spectra composed by two broad bands, one band centered at 645 nm (2E → 4A2) and another intense band from 700 to 850 nm (4T2 → 4A2).

  9. Er/Yb co-doped oxy-fluoride glass-ceramics core/polymer cladding optical fibers

    NASA Astrophysics Data System (ADS)

    Czerska, E.; Świderska, M.

    2014-11-01

    Erbium/ytterbium co-doped glasses can be applied as NIR laser sources (1.55 μm) or optical amplifiers in this range. About hundred meters of Er/Yb co-doped oxy-fluoride glass-ceramics fibers have been drawn from a glass preform followed by controlled annealing. Processing temperatures (drawing and annealing) were selected upon thermal analysis results (DTA/DSC plots). Glass-ceramic structure was confirmed by the XRD measurements. Obtained fibers show good optical properties. As a cladding material polymer material (acrylic resin) is considered due to its low deposition temperature and suitable value of refractive index.

  10. Ultraviolet and white photon avalanche upconversion in Ho{sup 3+}-doped nanophase glass ceramics

    SciTech Connect

    Lahoz, F.; Martin, I.R.; Calvilla-Quintero, J.M.

    2005-01-31

    Ho{sup 3+}-doped fluoride nanophase glass ceramics have been synthesized from silica-based oxyfluoride glass. An intense white emission light is observed by the naked eye under near infrared excitation at 750 nm. This visible upconversion is due to three strong emission bands in the primary color components, red, green, and blue. Besides, ultraviolet signals are also recorded upon the same excitation wavelength. The excitation mechanism of both the ultraviolet and the visible emissions is a photon avalanche process with a relatively low pump power threshold at about 20 mW. The total upconverted emission intensity has been estimated to increase by about a factor of 20 in the glass ceramic compared to the precursor glass, in which an avalanche type mechanism is not generated.

  11. Free volume effects on the fluorescence characteristics of sol-gel glasses doped with quinine sulphate

    NASA Astrophysics Data System (ADS)

    Meneses-Nava, M. A.; Barbosa-García, O.; Díaz-Torres, L. A.; Chávez-Cerda, S.; King, T. A.

    1999-12-01

    The broadening of the absorption and fluorescence spectra and the red shift of the fluorescence maximum of quinine sulfate doped sol-gel glasses, before and after PMMA polymer impregnation, are investigated at different concentrations. The fluorescence decay of the quinine sulfate doped samples does not fit to a single exponential, as it does in ethanol solutions. We found that a double exponential gives a good fit to the obtained results. Introduction of solvent to fill the pores of the matrix does not only have the same effect as the polymer, but also reveals the strong attachment of the molecules to the pore walls and the influence of the interaction with the cage.

  12. Dy{sup 3+}-doped Ga–Sb–S chalcogenide glasses for mid-infrared lasers

    SciTech Connect

    Zhang, Mingjie; Yang, Anping; Peng, Yuefeng; Zhang, Bin; Ren, He; Guo, Wei; Yang, Yan; Zhai, Chengcheng; Wang, Yuwei; Yang, Zhiyong; Tang, Dingyuan

    2015-10-15

    Highlights: • Novel Ga–Sb–S chalcogenide glasses doped with Dy{sup 3+} ions were synthesized. • The glasses show good thermal stability and excellent infrared transparency. • The glasses show low phonon energy and intense mid-infrared emissions. • The mid-infrared emissions have high quantum efficiency. • The mid-infrared emissions have large stimulated emission cross sections. - Abstract: Novel Ga–Sb–S chalcogenide glasses doped with different amount of Dy{sup 3+} ions were prepared. Their thermal stability, optical properties, and mid-infrared (MIR) emission properties were investigated. The glasses show good thermal stability, excellent infrared transparency, very low phonon energy (∼306 cm{sup −1}), and intense emissions centered at 2.95, 3.59, 4.17 and 4.40 μm. Three Judd–Ofelt intensity parameters (Ω{sub 2} = 8.51 × 10{sup −20} cm{sup 2}, Ω{sub 4} = 2.09 × 10{sup −20} cm{sup 2}, and Ω{sub 6} = 1.60 × 10{sup −20} cm{sup 2}) are obtained, and the related radiative transition properties are evaluated. The high quantum efficiencies and large stimulated emission cross sections of the MIR emissions (88.10% and 1.11 × 10{sup −20} cm{sup 2} for 2.95 μm emission, 75.90% and 0.38 × 10{sup −20} cm{sup 2} for 4.40 μm emission, respectively) in the Dy{sup 3+}-doped Ga–Sb–S glasses make them promising gain materials for the MIR lasers.

  13. Preventing photodarkening in ytterbium-doped high power fiber lasers; correlation to the UV-transparency of the core glass.

    PubMed

    Engholm, M; Norin, L

    2008-01-21

    Photodarkening experiments are performed on ytterbium-doped silicate glass samples. A strong charge-transfer (CT) absorption band near 230nm in aluminosilicate glass is found to be correlated to the mechanism of induced color center formation. Excitation into the CT-absorption band generates similar color centers as observed in ytterbium-doped fiber lasers under 915nm high power diode pumping. The position of the CT-absorption band is compositional dependent and is shifted to shorter wavelengths in ytterbium doped phosphosilicate glass. Very low levels of photodarkening is observed for the ytterbium doped phosphosilicate glass composition under 915nm high power diode pumping. Possible excitation routes to reach the CT-absorption band under 915nm pumping are discussed.

  14. Optical Characterization of Nd3+ and Er3+ Doped-Lead-Indium Phosphate Glasses

    SciTech Connect

    Brito, Taisa B.; Vermelho, M. V. D.; Gouveia, E. A.; de Araujo, M. T.; Guedes, I.; Loong, C. K.; Boatner, Lynn A

    2007-01-01

    In this work, Judd-Ofelt analysis is applied to rare-earth-doped lead-indium-phosphate glasses (RE-PbInPO{sub 4}, where RE = Er{sup 3+} and Nd{sup 3+}) in order to evaluate their potential as both glass laser systems and amplifier materials. The phenomenological Judd-Ofelt parameters {Omega}{sub (2)}, {Omega}{sub (4)}, and {Omega}{sub (6)} are determined for both rare-earth ions together with their quality factors and compared with the equivalent parameters for several other host glasses. The spontaneous emission probabilities and the lifetimes of the Nd{sup 3+} {sup 4}F{sub 3/2} laser transitions are determined and analyzed as a function of the optical quality factor. For Nd{sup 3+}-PbInPO{sub 4}, glass fluorescence emission (890, 1058, and 1330 nm) lines are observed. Highly efficient infrared-to-visible frequency up-conversion at 530, 550, and 670 nm as well as an intense infrared fluorescence emission ({approx}1540 nm) is observed in Er{sup 3+}-doped PbIn(PO{sub 4}) glasses pumped using 800 nm radiation excitation.

  15. Spectroscopic properties of transparent Er-doped oxyfluoride glass-ceramics with GdF₃.

    PubMed

    Środa, Marcin; Szlósarczyk, Krzysztof; Różański, Marek; Sitarz, Maciej; Jeleń, Piotr

    2015-01-01

    Optically active glass-ceramics (GC) with the low-phonon phases of fluorides, doped with Er(3+) was studied. Glass based on SiO₂-Al₂O₃-Na₂F₂-Na₂O-GdF₃-BaO system was obtained. Dopant were introduced to the glass in an amount of 0.01 mol Er₂O₃ per 1 mol of glass. DTA/DSC study shows multi-stage crystallization. XRD identification of obtained phases did not confirm the presence of pure GdF₃ phase. Instead of that ceramization process led to formation of NaGdF₄ and BaGdF₅. The structural changes were studied using FT-IR spectroscopic method. The study of luminescence of the samples confirmed that optical properties of the obtained GC depend on crystallizing phases during ceramization. Time resolved spectroscopy of Er-doped glass showed the 3 and 8 times increase of lifetime of emission from (4)S₃/₂ and (4)F₉/₂ states, respectively. It confirms the erbium ions have ability to locate in the low phonon gadolinium-based crystallites. The results give possibility to obtain a new material for optoelectronic application. PMID:25049170

  16. Spectroscopic properties of transparent Er-doped oxyfluoride glass-ceramics with GdF₃.

    PubMed

    Środa, Marcin; Szlósarczyk, Krzysztof; Różański, Marek; Sitarz, Maciej; Jeleń, Piotr

    2015-01-01

    Optically active glass-ceramics (GC) with the low-phonon phases of fluorides, doped with Er(3+) was studied. Glass based on SiO₂-Al₂O₃-Na₂F₂-Na₂O-GdF₃-BaO system was obtained. Dopant were introduced to the glass in an amount of 0.01 mol Er₂O₃ per 1 mol of glass. DTA/DSC study shows multi-stage crystallization. XRD identification of obtained phases did not confirm the presence of pure GdF₃ phase. Instead of that ceramization process led to formation of NaGdF₄ and BaGdF₅. The structural changes were studied using FT-IR spectroscopic method. The study of luminescence of the samples confirmed that optical properties of the obtained GC depend on crystallizing phases during ceramization. Time resolved spectroscopy of Er-doped glass showed the 3 and 8 times increase of lifetime of emission from (4)S₃/₂ and (4)F₉/₂ states, respectively. It confirms the erbium ions have ability to locate in the low phonon gadolinium-based crystallites. The results give possibility to obtain a new material for optoelectronic application.

  17. Spectroscopic properties in Er3+/Yb3+ Co-doped fluorophosphate glass

    NASA Astrophysics Data System (ADS)

    Zheng, Tao; Qin, Jie-Ming; Jiang, Da-Yong; Lü, Jing-Wen; Xiao, Sheng-Chun

    2012-04-01

    Using the technique of high-temperature melting, a new Er3+/Yb3+ co-doped fluorophosphate glass was prepared. The absorption and fluorescence spectra were investigated in depth. The effect of Er3+ and Yb3+ concentration on the spectroscopic properties of the glass sample was also discussed. According to the Judd—Ofelt theory, the oscillator strength was computed. The lifetime of 4I13/2 level (τm) of Er3+ ions was 8.23 ms, and the full width at half maximum of the dominating emission peak was 68 nm at 1.53 μm. The large stimulated emission cross section of the Er3+ was calculated by the McCumber theory. The spectroscopic properties of Er3+ ion were compared with those in different glasses. The full width at half maximum and σe are larger than those of other glass hosts, indicating this studied glass may be a potentially useful candidate for high-gain erbium-doped fiber amplifier.

  18. Linear and nonlinear optical characteristics of Te nanoparticles-doped germanate glasses

    NASA Astrophysics Data System (ADS)

    Xu, Zhousu; Guo, Qiangbing; Liu, Chang; Ma, Zhijun; Liu, Xiaofeng; Qiu, Jianrong

    2016-10-01

    Te nanoparticles (NPs)-doped GeO2-MgO-B2O3-Al2O3-TeO2 glasses were prepared by the conventional melt-quenching method. Based on X-ray photoelectron spectroscopy, Raman spectroscopy and transmission electron microscope observation, the coloration of the glass at high TeO2 concentration is ascribed to the precipitation of elemental Te NPs with a size of 5-10 nm in the germanate glass. Optical absorption spectra and nonlinear optical (NLO) properties of the glass samples were analyzed by UV-3600 spectrophotometry and Z-scan technique, respectively. The nonlinear absorption coefficient ( β) and the imaginary part of the third-order NLO susceptibility (Im χ (3)) were estimated to be 1.74 cm/GW and 1.142 × 10-12 esu for laser power of 95 μW, respectively. Due to the excellent NLO properties, the Te NPs-doped germanate glasses may have potential applications for ultrafast optical switch and photonics.

  19. Acoustic vibrations of semiconductor nanocrystals in doped glasses

    NASA Astrophysics Data System (ADS)

    Verma, Prabhat; Cordts, W.; Irmer, G.; Monecke, J.

    1999-08-01

    Polarization-dependent low-frequency off-resonant Raman scattering has been studied from various commercially available filter glass samples, which contain CdSxSe1-x nanoparticles embedded in a glass matrix. In order to distinguish the confined acoustic phonons from the glass background, the spectra have been compared with those obtained from the base material, which does not contain nanoparticles. Polarized and depolarized scattering from confined acoustic phonons was distinctly resolved near the laser line and overtones of the polarized modes were observed. A theoretical treatment, which establishes a relation between the particle size, the frequencies, and the widths of various phonons, taking into account the matrix influence on the vibrational spectrum and on its damping, is presented. The material-dependent generalized form of this model enables one to use it for any given combination of particle and matrix materials. A good agreement between the experimental and the theoretical results is found. The nanoparticle sizes obtained from Raman scattering agree well with those obtained from transmission electron microscope and anomalous small angle x-ray scattering experiments.

  20. Copper oxide and selenide nanoparticles embedded into sol-gel-derived silica glasses doped with europium

    NASA Astrophysics Data System (ADS)

    Gurin, Valerij S.; Yumashev, Konstantin V.; Prokoshin, P. V.; Zolotovskaya, S. A.; Alexeenko, A. A.

    2002-11-01

    The silica sol-gel derived glasses co-doped with CuxO and CuxSe nanoparticles and Eu3+ ions have been fabricated. The analysis of luminescence spectra of a series of glasses with different composition allows us to suppose the direct energy transfer between copper oxide nanoparticle and Eu3+ ion. A luminescence signal of europium ions occurs as the result of excitation of the complex active centres (SiO2:Cu2O:Eu3+) in the absorption range of copper oxide.

  1. Glass transition of associated solvents studied by fluorescence measurement of doped chromophores

    NASA Astrophysics Data System (ADS)

    Ye, Jing Yong; Hattori, Toshiaki; Inouye, Hideyuki; Ueta, Hiroshi; Nakatsuka, Hiroki; Maruyama, Yoshihiro; Ishikawa, Mitsuru

    1996-04-01

    The fluorescence lifetime of a triphenylmethane dye, malachite green, doped in three glass-forming associated solvents, 1-propanol, propylene glycol, and glycerol, was measured in a wide temperature range. For each sample three temperature regimes were found in the temperature dependence of the nonradiative relaxation time of malachite green. The lower crossover temperature corresponds to the calorimetric glass transition temperature, and the higher one, 30-50 K above the lower one, is attributed to the critical temperature that is predicted by mode-coupling theory.

  2. Microscopic Study of Glass Transition: Time-Resolved Fluorescence Measurements of Doped Dye Molecules

    NASA Astrophysics Data System (ADS)

    Nakatsuka, H.; Ye, J. Y.; Hattori, T.; Maruyama, Y.; Ishikawa, M.

    The microscopic dynamics of several monomeric and polymeric glass formers has been investigated by the time-resolved fluorescence measurement of doped malachite green molecules in a wide temperature range. For monomers and a polymer without side chains, beside a kink around the calorimetric glass transition temperature Tg, another crossover at Tc about 30 - 50 K above Tg has been clearly observed, which is in agreement with the prediction of the mode-coupling theory. On the other hand, for the complex polymers with side chains, although we could not distinguish any singularities above Tg, we observed another kink below Tg, which can be attributed to the side-chain motions.

  3. Preparation and luminescence of bulk oxyfluoride glasses doped with Ag nanoclusters.

    PubMed

    Tikhomirov, V K; Rodríguez, V D; Kuznetsov, A; Kirilenko, D; Van Tendeloo, G; Moshchalkov, V V

    2010-10-11

    Bulk oxyfluoride glasses doped with Ag nanoclusters have been prepared using the melt quenching technique. When pumped in the absorption band of Ag nanoclusters between 300 to 500 nm, these glasses emit a very broad luminescence band covering all the visible range with a weak tail extending into the near infrared. The maximum of the luminescence band and its color shifts to the blue with a shortening of the excitation wavelength and an increasing ratio of oxide to fluoride components, resulting in white color luminescence at a particular ratio of oxide to fluoride; with a quantum yield above 20%. PMID:20941104

  4. Upconversion in Nd{sup 3+}-doped glasses: Microscopic theory and spectroscopic measurements

    SciTech Connect

    Oliveira, S. L.; Sousa, D. F. de; Andrade, A. A.; Nunes, L. A. O.; Catunda, T.

    2008-01-15

    In this work, we report a systematic investigation of upconversion losses and their effects on fluorescence quantum efficiency and fractional thermal loading in Nd{sup 3+}-doped fluoride glasses. The energy transfer upconversion ({gamma}{sub up}) parameter, which describes upconversion losses, was experimentally determined using different methods: thermal lens (TL) technique and steady state luminescence (SSL) measurements. Additionally, the upconversion parameter was also obtained from energy transfer models and excited state absorption measurements. The results reveal that the microscopic treatment provided by the energy transfer models is similar to the macroscopic ones achieved from the TL and SSL measurements because similar {gamma}{sub up} parameters were obtained. Besides, the achieved results also point out the migration-assisted energy transfer according to diffusion-limited regime rather than hopping regime as responsible for the upconversion losses in Nd-doped glasses.

  5. Superbroadband near-IR emission from praseodymium-doped bismuth gallate glasses.

    PubMed

    Zhou, Bo; Pun, Edwin Yue-Bun

    2011-08-01

    Superbroadband near-infrared (NIR) emission covering 1250 to 1680 nm wavelength has been obtained in praseodymium (Pr(3+)) singly doped bismuth gallate glasses. The emission originates from the (1)G(4)→(3)H(5) and (1)D(2)→(1)G(4) transitions at 1330 and 1490 nm wavelengths, respectively, and is due to the extremely low phonon energy (∼690 cm(-1)) and the unique ligand field of the glasses. It is shown that the emission line shape can be modified by adjusting the Pr(3+) concentration and the energy transfers involved. The results confirm that other than bismuth (Bi), chromium (Cr), nickel (Ni), and other chemical elements, Pr(3+) singly doped system is a promising alternative in achieving superbroadband NIR emission.

  6. Fabrication and properties of Yb-doped silica glass films for laser waveguide application

    NASA Astrophysics Data System (ADS)

    Jacqueline, A.-S.; Petit, V.; Gourbilleau, F.; Camy, P.; Doualan, J.-L.; Moncorgé, R.; Rizk, R.

    2006-05-01

    This paper describes the fabrication of Yb 3+-doped silica glass films prepared by RF magnetron sputtering for laser applications. The deposition parameters and the subsequent thermal treatments were accurately adjusted to obtain layers with appropriate structural characteristics (flat surface, homogeneity) and optical properties (refractive index, absorption and fluorescence emission). The structural properties of the deposited films have been investigated by infra-red absorption spectroscopy and atomic force microscopy, while the layer composition was determined by an Energy Dispersive X-ray spectrometer. The optical properties of the films have been investigated by time resolved photoluminescence, providing relevant parameters such as the Yb 3+ fluorescence lifetime that governs the high pump energy storage and laser efficiency. The obtained values of the lifetime are scaling from 50 to 610 μs, and therefore are comparable to those usually reported for Yb 3+-doped silica glass fibers.

  7. Nonlinear optical effects on the surface of acridine yellow-doped lead-tin fluorophosphate glass

    NASA Technical Reports Server (NTRS)

    He, K. X.; Bryant, William; Venkateswarlu, Putcha

    1991-01-01

    The second- and third-order nonlinear optical properties of acridine yellow-doped lead-tin fluorophosphate (LTF) glass have been directly studied by measurement of surface enhanced second harmonic generation and third harmonic generation. The three photon excitation fluorescence is also observed. Based on these results, the large nonlinearities of the acridine LTF system which is a new nonlinear optical material are experimentally demonstrated.

  8. DBR and DFB Lasers in Neodymium- and Ytterbium-Doped Photothermorefractive Glasses

    NASA Technical Reports Server (NTRS)

    Ryasnyanskiy, Aleksandr; Vorobiev, N.; Smirnov, V.; Lumeau, J.; Glebov, A.; Mokhun, O..; Spiegelberg, Ch.; Krainak, Michael A.; Glebov, A.; Glebov, L.

    2014-01-01

    The first demonstration, to the best of our knowledge, of distributed Bragg reflector (DBR) and monolithic distributed feedback (DFB) lasers in photothermorefractive glass doped with rare-earth ions is reported. The lasers were produced by incorporation of the volume Bragg gratings into the laser gain elements. A monolithic single-frequency solid-state laser with a line width of 250 kHz and output power of 150 mW at 1066 nm is demonstrated.

  9. Optically erasable samarium-doped fluorophosphate glasses for high-dose measurements in microbeam radiation therapy

    NASA Astrophysics Data System (ADS)

    Morrell, B.; Okada, G.; Vahedi, S.; Koughia, C.; Edgar, A.; Varoy, C.; Belev, G.; Wysokinski, T.; Chapman, D.; Sammynaiken, R.; Kasap, S. O.

    2014-02-01

    Previous work has demonstrated that fluorophosphate (FP) glasses doped with trivalent samarium (Sm3+) can be used as a dosimetric detector in microbeam radiation therapy (MRT) to measure high radiation doses and large dose variations with a resolution in the micrometer range. The present work addresses the use of intense optical radiation at 405 nm to erase the recorded dose information in Sm3+-doped FP glass plates and examines the underlying physics. We have evaluated both the conversion and optical erasure of Sm3+-doped FP glasses using synchrotron-generated high-dose x-rays at the Canadian Light Source. The Sm-ion valency conversion is accompanied by the appearance of x-ray induced optical absorbance due to the trapping of holes and electrons into phosphorus-oxygen hole (POHC) and electron (POEC) capture centers. Nearly complete Sm2+ to Sm3+ reconversion (erasure) may be achieved by intense optical illumination. Combined analysis of absorbance and electron spin resonance measurements indicates that the optical illumination causes partial disappearance of the POHC and the appearance of new POEC. The suggested model for the observed phenomena is based on the release of electrons during the Sm2+ to Sm3+ reconversion process, the capture of these electrons by POHC (and hence their disappearance), or by PO groups, with the appearance of new and/or additional POEC. Optical erasure may be used as a practical means to erase the recorded data and permits the reuse of these Sm-doped FP glasses in monitoring dose in MRT.

  10. Promethium-doped phosphate glass laser at 933 and 1098 nm

    SciTech Connect

    Krupke, W.F.; Shinn, M.D.; Kirchoff, T.A.; Finch, C.B.; Boatner, L.A.

    1987-12-28

    A promethium (Pm/sup 3 +/) laser has been demonstrated for the first time. Trivalent promethium 147 doped into a lead-indium-phosphate glass etalon was used to produce room-temperature four-level laser emission at wavelengths of 933 and 1098 nm. Spectroscopic and kinetic measurements have shown that Pm/sup 3 +/ is similar to Nd/sup 3 +/ as a laser active ion.

  11. Optical nonlinearities in semiconductor-doped glasses near and below the band edge

    NASA Astrophysics Data System (ADS)

    Bindra, K. S.; Oak, S. M.; Rustagi, K. C.

    1998-03-01

    We present a brief review of our recent experimental results on optical nonlinearities in semiconductor-doped glasses. It is shown that even below the absorption edge the nonlinearities are determined by nonlinear absorption. The optical Kerr effect is found to have a susceptibility which is comparable to that for nonlinear refraction. We also find that in degenerate four-wave mixing the observed intensity dependence can be strongly influenced by nonlinear absorption.

  12. Optically erasable samarium-doped fluorophosphate glasses for high-dose measurements in microbeam radiation therapy

    SciTech Connect

    Morrell, B.; Okada, G.; Vahedi, S.; Koughia, C. Kasap, S. O.; Edgar, A.; Varoy, C.; Belev, G.; Wysokinski, T.; Chapman, D.; Sammynaiken, R.

    2014-02-14

    Previous work has demonstrated that fluorophosphate (FP) glasses doped with trivalent samarium (Sm{sup 3+}) can be used as a dosimetric detector in microbeam radiation therapy (MRT) to measure high radiation doses and large dose variations with a resolution in the micrometer range. The present work addresses the use of intense optical radiation at 405 nm to erase the recorded dose information in Sm{sup 3+}-doped FP glass plates and examines the underlying physics. We have evaluated both the conversion and optical erasure of Sm{sup 3+}-doped FP glasses using synchrotron-generated high-dose x-rays at the Canadian Light Source. The Sm-ion valency conversion is accompanied by the appearance of x-ray induced optical absorbance due to the trapping of holes and electrons into phosphorus-oxygen hole (POHC) and electron (POEC) capture centers. Nearly complete Sm{sup 2+} to Sm{sup 3+} reconversion (erasure) may be achieved by intense optical illumination. Combined analysis of absorbance and electron spin resonance measurements indicates that the optical illumination causes partial disappearance of the POHC and the appearance of new POEC. The suggested model for the observed phenomena is based on the release of electrons during the Sm{sup 2+} to Sm{sup 3+} reconversion process, the capture of these electrons by POHC (and hence their disappearance), or by PO groups, with the appearance of new and/or additional POEC. Optical erasure may be used as a practical means to erase the recorded data and permits the reuse of these Sm-doped FP glasses in monitoring dose in MRT.

  13. White emission materials from glass doped with rare Earth ions: A review

    NASA Astrophysics Data System (ADS)

    Yasaka, P.; Kaewkhao, J.

    2016-03-01

    Solid State Lighting (SSL) based devices are predicted to play a crucial role in the coming years. Development of W-LED, which have an edge over traditional lighting sources due to their compact size, higher reliability, shock resistance, interesting design possibilities, higher transparency and an extremely long lifetime. Over the fifteen trivalent lanthanide ions, Dy3+ ions doped glasses are most appropriate for white light generation because of the fact that it exhibits two intense emission bands corresponds to the 4F9/2→6H15/2 (magnetic dipole) and 4F9/2→6H13/2 (electric dipole) transitions at around 480-500 nm and 580-600 nm pertaining to blue and yellow regions respectively. In this work, the developments of Dy3+ doped in several glass structures for white emitting materials application have reviewed. Properties of Dy3+ doped in glasses were discussed for use as a solid state lighting materials application.

  14. Influence of high magnetic field on the luminescence of Eu{sup 3+}-doped glass ceramics

    SciTech Connect

    Jiang, Wei; Chen, Weibo; Chen, Ping; Xu, Beibei; Zheng, Shuhong; Guo, Qiangbing; Liu, Xiaofeng E-mail: qjr@zju.edu.cn; Zhang, Junpei; Han, Junbo; Qiu, Jianrong E-mail: qjr@zju.edu.cn

    2014-09-28

    Rare earth (RE) doped materials have been widely exploited as the intriguing electronic configuration of RE ions offers diverse functionalities from optics to magnetism. However, the coupling of magnetism with photoluminescence (PL) in such materials has been rarely reported in spite of its fundamental significance. In the present paper, the effect of high pulsed magnetic field on the photoluminescence intensity of Eu{sup 3+}-doped nano-glass-ceramics has been investigated. In our experiment, Eu-doped oxyfluoride glass and glass ceramic were prepared by the conventional melt-quenching process and controlled heat treatment. The results demonstrate that the integrated PL intensity of Eu{sup 3+} decreases with the enhancement of magnetic field, which can be interpreted in terms of cooperation effect of Zeeman splitting and magnetic field induced change in site symmetry. Furthermore, as a result of Zeeman splitting, both blue and red shift in the emission peaks of Eu{sup 3+} can be observed, and this effect becomes more prominent with the increase of magnetic field. Possible mechanisms associated with the observed magneto-optical behaviors are suggested. The results of the present paper may open a new gate for modulation of luminescence by magnetic field and remote optical detection of magnetic field.

  15. Fabrication of uniformly dispersed nanoparticle-doped chalcogenide glass

    SciTech Connect

    Lu, Chao; Arnold, Craig; Almeida, Juliana M. P.; Yao, Nan

    2014-12-29

    The dispersion of metallic nanoparticles within a chalcogenide glass matrix has the potential for many important applications in active and passive optical materials. However, the challenge of particle agglomeration, which can occur during traditional thin film processing, leads to materials with poor performance. Here, we report on the preparation of a uniformly dispersed Ag-nanoparticle (Ag NP)/chalcogenide glass heterogeneous material prepared through a combined laser- and solution-based process. Laser ablation of bulk silver is performed directly within an arsenic sulfide/propylamine solution resulting in the formation of Ag NPs in solution with an average particle size of less than 15 nm as determined by dynamic light scattering. The prepared solutions are fabricated into thin films using standard coating processes and are then analyzed using energy-dispersive X-ray spectroscopy and transmission electron microscopy to investigate the particle shape and size distribution. By calculating the nearest neighbor index and standard normal deviate of the nanoparticle locations inside the films, we verify that a uniformly dispersed distribution is achieved through this process.

  16. Spectroscopic characteristics of chromium-doped mullite glass-ceramics

    SciTech Connect

    Wojtowicz, A.J.; Meng, W.; Lempicki, A.; Beall, G.H.; Hall, D.W.

    1988-06-01

    The chromium (3+) ion has been widely used as an optical activator in solid-state, tunable laser materials. High octahedral field-stabilization energy and resistance against both oxidation and reduction minimize the dependence of chromium (3+) on the solid-state host matrix. However, the high sensitivity of electronic structure on crystal field strength makes the appropriate choice of host the condition for success. Characteristics of chromium-doped mullite ceramics are discussed with reference to possible laser applications. Dominant features are attributed to large and inherent spectroscopic inhomogeneity of mullite. The spectroscopic data are analyzed using a generalized McCumber theory. The peak-stimulated emission cross section is 0.54 x 10 to the -20 sq cm. This together with preliminary single-pass measurements, indicate that gain for mullite is about 2.6 times smaller than gain for alexandrite.

  17. Structure and properties of strontium-doped phosphate-based glasses.

    PubMed

    Abou Neel, Ensanya A; Chrzanowski, Wojciech; Pickup, David M; O'Dell, Luke A; Mordan, Nicola J; Newport, Robert J; Smith, Mark E; Knowles, Jonathan C

    2009-05-01

    Owing to similarity in both ionic size and polarity, strontium (Sr2+) is known to behave in a comparable way to calcium (Ca2+), and its role in bone metabolism has been well documented as both anti-resorptive and bone forming. In this study, novel quaternary strontium-doped phosphate-based glasses, containing 1, 3 and 5 mol% SrO, were synthesized and characterized. (31)P magic angle spinning (MAS) nuclear magnetic resonance results showed that, as the Sr2+ content is increased in the glasses, there is a slight increase in disproportionation of Q2 phosphorus environments into Q(1) and Q3 environments. Moreover, shortening and strengthening of the phosphorus to bridging oxygen distance occurred as obtained from FTIR. The general broadening of the spectral features with Sr2+ content is most probably due to the increased variation of the phosphate-cation bonding interactions caused by the introduction of the third cation. This increased disorder may be the cause of the increased degradation of the Sr-containing glasses relative to the Sr-free glass. As confirmed from elemental analysis, all Sr-containing glasses showed higher Na2O than expected and this also could be accounted for by the higher degradation of these glasses compared with Sr-free glasses. Measurements of surface free energy (SFE) showed that incorporation of strontium had no effect on SFE, and samples had relatively higher fractional polarity, which is not expected to promote high cell activity. From viability studies, however, the incorporation of Sr2+ showed better cellular response than Sr(2+)-free glasses, but still lower than the positive control. This unfavourable cellular response could be due to the high degradation nature of these glasses and not due to the presence of Sr2+.

  18. Structure and properties of strontium-doped phosphate-based glasses

    PubMed Central

    Abou Neel, Ensanya A.; Chrzanowski, Wojciech; Pickup, David M.; O'Dell, Luke A.; Mordan, Nicola J.; Newport, Robert J.; Smith, Mark E.; Knowles, Jonathan C.

    2008-01-01

    Owing to similarity in both ionic size and polarity, strontium (Sr2+) is known to behave in a comparable way to calcium (Ca2+), and its role in bone metabolism has been well documented as both anti-resorptive and bone forming. In this study, novel quaternary strontium-doped phosphate-based glasses, containing 1, 3 and 5 mol% SrO, were synthesized and characterized. 31P magic angle spinning (MAS) nuclear magnetic resonance results showed that, as the Sr2+ content is increased in the glasses, there is a slight increase in disproportionation of Q2 phosphorus environments into Q1 and Q3 environments. Moreover, shortening and strengthening of the phosphorus to bridging oxygen distance occurred as obtained from FTIR. The general broadening of the spectral features with Sr2+ content is most probably due to the increased variation of the phosphate–cation bonding interactions caused by the introduction of the third cation. This increased disorder may be the cause of the increased degradation of the Sr-containing glasses relative to the Sr-free glass. As confirmed from elemental analysis, all Sr-containing glasses showed higher Na2O than expected and this also could be accounted for by the higher degradation of these glasses compared with Sr-free glasses. Measurements of surface free energy (SFE) showed that incorporation of strontium had no effect on SFE, and samples had relatively higher fractional polarity, which is not expected to promote high cell activity. From viability studies, however, the incorporation of Sr2+ showed better cellular response than Sr2+-free glasses, but still lower than the positive control. This unfavourable cellular response could be due to the high degradation nature of these glasses and not due to the presence of Sr2+. PMID:18826914

  19. Effect of silver nanoparticles on spectroscopic properties of Er3+ doped phosphate glass

    NASA Astrophysics Data System (ADS)

    Soltani, I.; Hraiech, S.; Horchani-Naifer, K.; Elhouichet, H.; Férid, M.

    2015-08-01

    The Er3+ doped zinc phosphate glasses containing Ag nanoparticles (Ag NPS) were synthesized from high purity raw materials by melt quenching method. The transmission electron microscopic (TEM) images confirm the presence of spherical silver NPs having average diameter in the range of 20-40 nm. A wide absorption band peaking at about 403 nm was observed due to surface plasmon resonance (SPR) of Ag NPs. The Judd-Ofelt (JO) parameters Ω2, Ω4 and Ω6, were determined for Er3+ ions using the absorption bands. The quality factor was determined and is found to be in the same order (0.52-1.12) than other host glasses. The enhanced photoluminescence (PL) intensity with Ag adding was attributed to the increased local field on the Er3+ ions located in the proximity of the NPs and/or the energy transfer from the metallic Ag NPs to the Er3+ ions. The absorption and emission cross-sections are calculated and determined for the 4I13/2 → 4I15/2 transition and then compared with other reported doped glasses. The phosphate glasses are promising gain media for developing the solid-state 1.53 μm optical amplifiers.

  20. NIR emission studies and dielectric properties of Er3+-doped multicomponent tellurite glasses

    NASA Astrophysics Data System (ADS)

    Sajna, M. S.; Thomas, Sunil; Jayakrishnan, C.; Joseph, Cyriac; Biju, P. R.; Unnikrishnan, N. V.

    2016-05-01

    Multicomponent tellurite glasses containing altered concentrations of Er2O3 (ranging from 0 to 1 mol%) were prepared by the standard melt quenching technique. Investigations through energy dispersive X-ray spectroscopy (EDS), Raman scattering spectroscopy, Fourier transform infrared (FTIR) spectroscopy, near-infrared (NIR) emission studies and dielectric measurement techniques were done to probe their compositional, structural, spectroscopic and dielectric characteristics. The broad emission together with the high values of the effective linewidth (~ 63 nm), stimulated emission cross-section (9.67 × 10- 21 cm2) and lifetime (2.56 ms) of 4I13/2 level for 0.5 mol% of Er3+ makes these glasses attractive for broadband amplifiers. From the measured capacitance and dissipation factor, the relative permittivity, dielectric loss and the conductivity were computed; which furnish the dielectric nature of the multicomponent tellurite glasses that depend on the applied frequency. Assuming the ideal Debye behavior as substantiated by Cole-Cole plot, an examination of the real and imaginary parts of impedance was performed. The power-law and Cole-Cole parameters were resolved for all the glass samples. From the assessment of the emission analysis and dielectric properties of the glass samples, it was obvious that the Er3+ ion concentration had played a vital role in tuning the optical and dielectric properties and the 0.5 mol% of Er3+ -doped glass was confirmed as the optimum composition.

  1. FTIR spectra and thermal properties of TiO2-doped iron phosphate glasses

    NASA Astrophysics Data System (ADS)

    Lu, Mingwei; Wang, Fu; Liao, Qilong; Chen, Kuiru; Qin, Jianfa; Pan, Sheqi

    2015-02-01

    Structure and thermal properties of xTiO2·(90 - x) (60P2O5-40Fe2O3)ṡ10CaF2 (x = 0, 5, 10, 15, 20 and 25 mol%) glasses are investigated in detail by Fourier Transform Infrared Spectrum (FTIR) and Differential Thermal Analysis (DTA), respectively. It is found that incorporation of TiO2 increase the density and glass transition temperature of iron phosphate system glass. The increment of doped-TiO2 can also strengthen phosphate network chains due to increasing O/P ratios and more orthophosphate (Q0) units formed in the glass structure at expense of pyrophosphate (Q1) units and metaphosphate (Q2) groups. Moreover, the structure of iron phosphate glass with TiO2 content contain distorted octahedral [TiO6] linked to phosphate unit through Psbnd Osbnd Ti bonds, thus enhanced structure cohesion and increased density obtained. The knowledge provides an improved understanding of the role of TiO2 in the structure of iron phosphate glasses.

  2. NIR emission studies and dielectric properties of Er(3+)-doped multicomponent tellurite glasses.

    PubMed

    Sajna, M S; Thomas, Sunil; Jayakrishnan, C; Joseph, Cyriac; Biju, P R; Unnikrishnan, N V

    2016-05-15

    Multicomponent tellurite glasses containing altered concentrations of Er2O3 (ranging from 0 to 1 mol%) were prepared by the standard melt quenching technique. Investigations through energy dispersive X-ray spectroscopy (EDS), Raman scattering spectroscopy, Fourier transform infrared (FTIR) spectroscopy, near-infrared (NIR) emission studies and dielectric measurement techniques were done to probe their compositional, structural, spectroscopic and dielectric characteristics. The broad emission together with the high values of the effective linewidth (~63 nm), stimulated emission cross-section (9.67 × 10(-21) cm(2)) and lifetime (2.56 ms) of (4)I13/2 level for 0.5 mol% of Er(3+) makes these glasses attractive for broadband amplifiers. From the measured capacitance and dissipation factor, the relative permittivity, dielectric loss and the conductivity were computed; which furnish the dielectric nature of the multicomponent tellurite glasses that depend on the applied frequency. Assuming the ideal Debye behavior as substantiated by Cole-Cole plot, an examination of the real and imaginary parts of impedance was performed. The power-law and Cole-Cole parameters were resolved for all the glass samples. From the assessment of the emission analysis and dielectric properties of the glass samples, it was obvious that the Er(3+) ion concentration had played a vital role in tuning the optical and dielectric properties and the 0.5 mol% of Er(3+) -doped glass was confirmed as the optimum composition. PMID:26967514

  3. NIR emission studies and dielectric properties of Er(3+)-doped multicomponent tellurite glasses.

    PubMed

    Sajna, M S; Thomas, Sunil; Jayakrishnan, C; Joseph, Cyriac; Biju, P R; Unnikrishnan, N V

    2016-05-15

    Multicomponent tellurite glasses containing altered concentrations of Er2O3 (ranging from 0 to 1 mol%) were prepared by the standard melt quenching technique. Investigations through energy dispersive X-ray spectroscopy (EDS), Raman scattering spectroscopy, Fourier transform infrared (FTIR) spectroscopy, near-infrared (NIR) emission studies and dielectric measurement techniques were done to probe their compositional, structural, spectroscopic and dielectric characteristics. The broad emission together with the high values of the effective linewidth (~63 nm), stimulated emission cross-section (9.67 × 10(-21) cm(2)) and lifetime (2.56 ms) of (4)I13/2 level for 0.5 mol% of Er(3+) makes these glasses attractive for broadband amplifiers. From the measured capacitance and dissipation factor, the relative permittivity, dielectric loss and the conductivity were computed; which furnish the dielectric nature of the multicomponent tellurite glasses that depend on the applied frequency. Assuming the ideal Debye behavior as substantiated by Cole-Cole plot, an examination of the real and imaginary parts of impedance was performed. The power-law and Cole-Cole parameters were resolved for all the glass samples. From the assessment of the emission analysis and dielectric properties of the glass samples, it was obvious that the Er(3+) ion concentration had played a vital role in tuning the optical and dielectric properties and the 0.5 mol% of Er(3+) -doped glass was confirmed as the optimum composition.

  4. Enhancement of cells proliferation and control of bioactivity of strontium doped glass

    NASA Astrophysics Data System (ADS)

    Oudadesse, H.; Dietrich, E.; Bui, X. V.; Le Gal, Y.; Pellen, P.; Cathelineau, G.

    2011-08-01

    Bioactivity and chemical reactivity of bioactive glass offer the ability to bond for soft and hard biological tissues. In this work, synthesis was carried out by using melting and rapid quenching. Strontium was introduced as trace element at different contents in the glass matrix, according to its concentration in the bone matrix. This chemical element presents a high interest in the bone metabolism activity. Investigations were conducted on the surface of biomaterials by using in vitro assay after immersion in SBF. Several physico-chemical methods such as SEM, FTIR, NMR, ICP-OES and MTT test were employed to highlight the effects of the Sr. The in vitro experiments showed that after soaking in SBF, the behaviour of pure glass is different compared to glass doped with Sr. NMR analyses showed in the 29Si MAS-NMR that glass matrix undergoes some changes after in vitro assays particularly the emergence of new components attributed to Q 3(OH). The presence of Sr slowed down the bioactivity of glass after immersion in SBF. The non toxic character of compounds was confirmed. Introduction of Sr at 0.1 wt % induce an enhancement of cells at about 14.3%.

  5. Ni(2+) doped glass ceramic fiber fabricated by melt-in-tube method and successive heat treatment.

    PubMed

    Fang, Zaijin; Zheng, Shupei; Peng, Wencai; Zhang, Hang; Ma, Zhijun; Dong, Guoping; Zhou, Shifeng; Chen, Danping; Qiu, Jianrong

    2015-11-01

    Glass ceramic fibers containing Ni(2+) doped LiGa(5)O(8) nanocrystals were fabricated by a melt-in-tube method and successive heat treatment. Fiber precursors were prepared by drawing at high temperature where fiber core glass was melted while fiber clad glass was softened. After heat treatment, LiGa(5)O(8) nanocrystals were precipitated in the fiber core. Excited by 980 nm laser, efficient broadband near-infrared emission was observed in the glass ceramic fiber compared to that of precursor fiber. The melt-in-tube method can realize controllable crystallization and is suitable for fabrication of novel glass ceramic fibers. The Ni(2+)-doped glass ceramic fiber is promising for broadband optical amplification. PMID:26561096

  6. Ni(2+) doped glass ceramic fiber fabricated by melt-in-tube method and successive heat treatment.

    PubMed

    Fang, Zaijin; Zheng, Shupei; Peng, Wencai; Zhang, Hang; Ma, Zhijun; Dong, Guoping; Zhou, Shifeng; Chen, Danping; Qiu, Jianrong

    2015-11-01

    Glass ceramic fibers containing Ni(2+) doped LiGa(5)O(8) nanocrystals were fabricated by a melt-in-tube method and successive heat treatment. Fiber precursors were prepared by drawing at high temperature where fiber core glass was melted while fiber clad glass was softened. After heat treatment, LiGa(5)O(8) nanocrystals were precipitated in the fiber core. Excited by 980 nm laser, efficient broadband near-infrared emission was observed in the glass ceramic fiber compared to that of precursor fiber. The melt-in-tube method can realize controllable crystallization and is suitable for fabrication of novel glass ceramic fibers. The Ni(2+)-doped glass ceramic fiber is promising for broadband optical amplification.

  7. Mössbauer spectroscopy of europium-doped fluorochlorozirconate glasses and glass ceramics: optimization of storage phosphors in computed radiography

    PubMed Central

    Pfau, C; Paßlick, C; Gray, S; Johnson, JA; Johnson, CE; Schweizer, S

    2013-01-01

    Eu2+-doped fluorochlorozirconate (FCZ) glasses and glass ceramics, which are being developed for medical and photovoltaic applications, have been analysed by Mössbauer spectroscopy. The oxidation state and chemical environment of the europium ions, which are important for the performance of these materials, were investigated. Routes for maximizing the divalent europium content were investigated. By using EuCl2 instead of EuF2 in the starting material a fraction of about 90% of the europium was maintained in the Eu2+ state as opposed to about 70% when using EuF2. The glass ceramics produced by subsequent thermal processing contain BaCl2 nanocrystals in which Eu2+ is incorporated, as shown by the narrower linewidth in the Mössbauer spectrum. Debye temperatures of 147 K and 186 K for Eu2+ and Eu3+, respectively, were determined from temperature dependent Mössbauer measurements. The f-factors were used to obtain the Eu2+/Eu3+ ratio from the area ratio of the corresponding absorption lines. PMID:23603535

  8. Structural and optical characterization of Er3+ doped zinc telluroborate glasses for green laser applications

    NASA Astrophysics Data System (ADS)

    Annapoorani, K.; Ravindran, T. R.; Murthy, N. Suriya; Marimuthu, K.

    2015-06-01

    A new series of Erbium doped Zinc telluroborate glasses were prepared by melt quenching technique. The stretching and bending vibrations of the B-O and Te-O bonds in the prepared glass network were explored through Raman spectra. The nature of the metal-ligand bond was determined using optical absorption spectra through Nephelauxetic ratio (β) and Bonding parameter (δ) studies. The Judd-Ofelt (JO) parameters (Ω2, Ω4, Ω6) and the oscillator strengths were calculated following JO theory. The relatively higher Ω2 values reveal the higher asymmetry nature. The green emission corresponding to the 2H11/2+4S3/2→4I15/2 transition was observed at around 550 nm and the luminescence quenching occurs beyond 1.0 wt% of Erbium ion concentration. Radiative properties for the 1.0EZTB glass are found to be higher and its suitability towards green laser applications were discussed and reported.

  9. Influence of silver nanoparticles on the spectroscopic properties of Sm3+ doped boro-phosphate glasses

    NASA Astrophysics Data System (ADS)

    Suthanthirakumar, P.; Marimuthu, K.

    2016-05-01

    The Sm3+ doped novel boro-phosphate glasses containing silver nanoparticles (NPs) (SmBPxA) have been prepared following the melt quenching technique and their structural and spectroscopic behavior were studied through HR-TEM, optical absorption and photoluminescence spectral measurements. The TEM analysis validates the existence of Ag NPs with an average diameter of ~8 nm. The Surface plasmon resonance (SPR) band of silver NPs was found at around 600 nm from the absorption spectrum of the Sm3+ ions free glass sample. The optical band gap energy (Eopt) corresponding to the direct and indirect allowed transitions and the Urbach energy (ΔE) values were determined from the absorption spectral measurements. The luminescence intensity is found to get enhance when the Ag NPs were embedded along with the Sm3+ ions in the prepared glasses due to the local electric field effect around the rare earth (RE) ion site produced by the SPR of Ag NPs.

  10. Investigation of spectroscopy and the dual energy transfer mechanisms of Sm3+-doped telluroborate glasses

    NASA Astrophysics Data System (ADS)

    Van Do, Phan; Tuyen, Vu Phi; Quang, Vu Xuan; Hung, Le Xuan; Thanh, Luong Duy; Ngoc, Tran; Van Tam, Ngo; Huy, Bui The

    2016-05-01

    The absorption, luminescence, Raman spectra and lifetimes of Sm-doped alkali telluroborate glasses (TB glasses) TB:Sm3+ have been investigated. The dual energy transfers including energy transfer between Sm3+ - Sm3+ pairs and Sm3+ - non-bridging oxygen (NBO) intrinsic defects were investigated. The concentration quenching of luminescence intensity was explained by the non-radiative energy transfer between the Sm3+ ions through the cross-relaxation mechanism. The decay curves are single exponentials with low concentrations (lower 0.10 mol%) and become non-exponentials at higher concentrations. The non-exponential decay curves are fitted to the Inokuti and Hirayama model to give the energy transfer parameters between Sm3+ ions. The dominant interaction mechanism for energy transfer process is dipole-dipole interaction. The energy transfer induced Sm3+ photoluminescence enhancement in tellurite glass was experimentally studied and confirmed.

  11. Blocking effect of crystal–glass interface in lanthanum doped barium strontium titanate glass–ceramics

    SciTech Connect

    Wang, Xiangrong; Zhang, Yong; Baturin, Ivan; Liang, Tongxiang

    2013-10-15

    Graphical abstract: The blocking effect of the crystal–glass interface on the carrier transport behavior in the lanthanum doped barium strontium titanate glass–ceramics: preparation and characterization. - Highlights: • La{sub 2}O{sub 3} addition promotes the crystallization of the major crystalline phase. • The Z″ and M″ peaks exist a significant mismatch for 0.5 mol% La{sub 2}O{sub 3} addition. • The Z″ and M″ peaks separate obviously for 1.0 mol% La{sub 2}O{sub 3} addition. • Crystallite impedance decreases while crystal–glass interface impedance increases. • La{sub 2}O{sub 3} addition increases blocking factor of the crystal–glass interface. - Abstract: The microstructures and dielectric properties in La{sub 2}O{sub 3}-doped barium strontium titanate glass–ceramics have been investigated by scanning electron microscopy (SEM) and impedance spectroscopy. SEM analysis indicated that La{sub 2}O{sub 3} additive decreases the average crystallite size. Impedance spectroscopy revealed that the positions of Z″ and M″ peaks are close for undoped samples. When La{sub 2}O{sub 3} concentration is 0.5 mol%, the Z″ and M″ peaks show a significant mismatch. Furthermore, these peaks separate obviously for 1.0 mol% La{sub 2}O{sub 3} addition. With increasing La{sub 2}O{sub 3} concentration, the contribution of the crystallite impedance becomes smaller, while the contribution of the crystal–glass interface impedance becomes larger. More interestingly, it was found that La{sub 2}O{sub 3} additive increases blocking factor of the crystal–glass interface in the temperature range of 250–450 °C. This may be attributed to a decrease of activation energy of the crystallite and an increase of the crystal–glass interface area.

  12. White light simulation and luminescence studies on Dy3+ doped Zinc borophosphate glasses

    NASA Astrophysics Data System (ADS)

    Vijayakumar, R.; Venkataiah, G.; Marimuthu, K.

    2015-01-01

    The Dy3+ doped Zinc borophosphate glasses with the chemical composition (79-x)B2O3+xP2O5+10Li2O+10ZnO+1Dy2O3 (where x=0, 10, 20, 30 and 50 in wt%) have been prepared by melt quenching technique. The prepared glass samples were characterized through optical absorption, emission and decay measurements. The bonding parameters, optical band gap and Urbach's energy values were calculated from the optical absorption spectra to explore the bonding nature of the Dy-O metal ligand and electronic band structure of the studied glasses. Judd-Ofelt (JO) intensity parameters were calculated from the absorption spectra by using the JO theory and it gives information about symmetry of the ligand environment around the Dy3+ ion site. The Y/B intensity ratio and radiative properties were obtained from the emission spectra and the results were compared with the reported literature. The x, y chromaticity color coordinates of the studied glasses were analyzed using a CIE 1931 color chromaticity diagram and found that the x, y coordinates lie in the white light region. The decay curve measurements of the prepared glasses exhibit non-exponential behavior and are well fitted to Inokuti-Hirayama (IH) model to understand the energy transfer mechanism between Dy3+ ions. The Q, R0 and CDA values of the prepared Dy3+ doped glasses were obtained from the IH model and the results were discussed and compared with the reported literature.

  13. Role of glass structure in defining the chemical dissolution behavior, bioactivity and antioxidant properties of zinc and strontium co-doped alkali-free phosphosilicate glasses.

    PubMed

    Kapoor, Saurabh; Goel, Ashutosh; Tilocca, Antonio; Dhuna, Vikram; Bhatia, Gaurav; Dhuna, Kshitija; Ferreira, José M F

    2014-07-01

    We investigated the structure-property relationships in a series of alkali-free phosphosilicate glass compositions co-doped with Zn(2+) and Sr(2+). The emphasis was laid on understanding the structural role of Sr(2+) and Zn(2+) co-doping on the chemical dissolution behavior of glasses and its impact on their in vitro bioactivity. The structure of glasses was studied using molecular dynamics simulations in combination with solid state nuclear magnetic resonance spectroscopy. The relevant structural properties are then linked to the observed degradation behavior, in vitro bioactivity, osteoblast proliferation and oxidative stress levels. The apatite-forming ability of glasses has been investigated by X-ray diffraction, infrared spectroscopy and scanning electron microscopy-energy-dispersive spectroscopy after immersion of glass powders/bulk in simulated body fluid (SBF) for time durations varying between 1h and 14 days, while their chemical degradation has been studied in Tris-HCl in accordance with ISO 10993-14. All the glasses exhibit hydroxyapatite formation on their surface within 1-3h of their immersion in SBF. The cellular responses were observed in vitro on bulk glass samples using human osteosarcoma MG63 cell line. The dose-dependent cytoprotective effect of glasses with respect to the concentration of zinc and strontium released from the glasses is also discussed. PMID:24709542

  14. Role of glass structure in defining the chemical dissolution behavior, bioactivity and antioxidant properties of zinc and strontium co-doped alkali-free phosphosilicate glasses.

    PubMed

    Kapoor, Saurabh; Goel, Ashutosh; Tilocca, Antonio; Dhuna, Vikram; Bhatia, Gaurav; Dhuna, Kshitija; Ferreira, José M F

    2014-07-01

    We investigated the structure-property relationships in a series of alkali-free phosphosilicate glass compositions co-doped with Zn(2+) and Sr(2+). The emphasis was laid on understanding the structural role of Sr(2+) and Zn(2+) co-doping on the chemical dissolution behavior of glasses and its impact on their in vitro bioactivity. The structure of glasses was studied using molecular dynamics simulations in combination with solid state nuclear magnetic resonance spectroscopy. The relevant structural properties are then linked to the observed degradation behavior, in vitro bioactivity, osteoblast proliferation and oxidative stress levels. The apatite-forming ability of glasses has been investigated by X-ray diffraction, infrared spectroscopy and scanning electron microscopy-energy-dispersive spectroscopy after immersion of glass powders/bulk in simulated body fluid (SBF) for time durations varying between 1h and 14 days, while their chemical degradation has been studied in Tris-HCl in accordance with ISO 10993-14. All the glasses exhibit hydroxyapatite formation on their surface within 1-3h of their immersion in SBF. The cellular responses were observed in vitro on bulk glass samples using human osteosarcoma MG63 cell line. The dose-dependent cytoprotective effect of glasses with respect to the concentration of zinc and strontium released from the glasses is also discussed.

  15. Synthesis, characterization and processing of active rare earth-doped chalcohalide glasses

    NASA Astrophysics Data System (ADS)

    Debari, Roberto Mauro

    Applications for infrared-transmitting non-oxide glass fibers span a broad range of topics. They can be used in the military, the medical field, telecommunications, and even in agriculture. Rare earth ions are used as dopants in these glasses in order to stimulate emissions in the infrared spectral region. In order to extend the host glass transmission further into the infrared, selenium atoms were substituted for sulfur in the established Ge-S-I chalcohalide glass system and the fundamental properties of these latter glasses were explored. Over 30 different compositions in the Ge-Se-I glass system were investigated as to their thermal and optical properties. The resulting optimum host with a composition of Ge15Se80I5 has a broad transmission range from 0.7 mum to 17.0 mum and a high working range over 145°C. The host glass also exhibited a Tg of 125°C, making rotational casting of a cladding tube for rod-and-tube fiberization a possibility. The base glass was doped with 1000 to 4000 ppm/wt of erbium, dysprosium, or neodymium. When doped with Er3+-ions, absorptions at 1.54 mum and 3.42 mum were observed. Nd3+-doping resulted in an absorption peak near 4.24 mum and Dy3+ ions caused absorption at 1.30 mum. Fluorescence emissions were found for neodymium at 1.396 mum with a FWHM of 74 nm, and for dysprosium at 1.145 mum with a FWHM of 75 nm, at 1.360 mum with a FWHM of 98 rim and at 1.674 mum with a FWHM of 60 nm. High optical quality tubes of the host glass could be formed using rotational casting in silica ampoules. Glass tubes, 4 to 6 cm long with a 1 cm outer diameter and a tailored inner-hole diameter ranging from 0.4 to 0.6 cm could be synthesized by this process with excellent dimensional tolerances around the circumference as well as along the length. A preform of this size provided 25 continuous meters of unclad fiber with diameters ranging from 140 to 200 mum. A UV-curable acrylate cladding was applied via an external coating cup. An x-ray analysis of the

  16. Structural features of silver-doped phosphate glasses in zone of femtosecond laser-induced modification

    SciTech Connect

    Vasileva, A.A.; Nazarov, I.A.; Olshin, P.K.; Povolotskiy, A.V.; Sokolov, I.A.; Manshina, A.A.

    2015-10-15

    Femtosecond (fs) laser writing of two-dimensional microstructures (waveguides) is demonstrated in bulk phosphate glasses doped with silver ions. Silver-content phosphate and silver-content niobium–phosphate glasses with high concentration of silver oxide 55 mol% were used as samples for fs laser writing. The chemical network structure of the synthesized samples is analyzed through Raman spectroscopy and was found to be strongly sensitive to Nb incorporation. It was found that the direct laser writing process enables not only reorganization of glass network, but also formation of color centers and silver nanoparticles that are revealed in appearance of luminescence signal and plasmon absorption. The process of NPs' formation is more efficient for Nb-phosphate glass, while color centers are preferably formed in phosphate glass. - Graphical abstract: Formation of silver NPs on the surface of 0.5Ag{sub 2}O–0.4P{sub 2}O{sub 5}–0,1Nb{sub 2}O{sub 5} glass induced by CW laser irradiation. - Highlights: • The structure of 0.5Ag{sub 2}O–0.1Nb{sub 2}O{sub 5}–0.4P{sub 2}O{sub 5} and 0.55Ag{sub 2}O–0.45P{sub 2}O{sub 5} glasses was investigated by Raman spectroscopy. • Fs laser writing induces formation of silver NPs in investigated glasses. • Surface plasmon resonance in the absorption spectra confirms the formation of NP. • The possibility of CW laser induced formation of silver NPs on the surface of sample with niobium is shown.

  17. Comparison of Borate Bioactive Glass and Calcium Sulfate as Implants for the Local Delivery of Teicoplanin in the Treatment of Methicillin-Resistant Staphylococcus aureus-Induced Osteomyelitis in a Rabbit Model

    PubMed Central

    Jia, Wei-Tao; Fu, Qiang; Huang, Wen-Hai

    2015-01-01

    There is growing interest in biomaterials that can cure bone infection and also regenerate bone. In this study, two groups of implants composed of 10% (wt/wt) teicoplanin (TEC)-loaded borate bioactive glass (designated TBG) or calcium sulfate (TCS) were created and evaluated for their ability to release TEC in vitro and to cure methicillin-resistant Staphylococcus aureus (MRSA)-induced osteomyelitis in a rabbit model. When immersed in phosphate-buffered saline (PBS), both groups of implants provided a sustained release of TEC at a therapeutic level for up to 3 to 4 weeks while they were gradually degraded and converted to hydroxyapatite. The TBG implants showed a longer duration of TEC release and better retention of strength as a function of immersion time in PBS. Infected rabbit tibiae were treated by debridement, followed by implantation of TBG or TCS pellets or intravenous injection with TEC, or were left untreated. Evaluation at 6 weeks postimplantation showed that the animals implanted with TBG or TCS pellets had significantly lower radiological and histological scores, lower rates of MRSA-positive cultures, and lower bacterial loads than those preoperatively and those of animals treated intravenously. The level of bone regeneration was also higher in the defects treated with the TBG pellets. The results showed that local TEC delivery was more effective than intravenous administration for the treatment of MRSA-induced osteomyelitis. Borate glass has the advantages of better mechanical strength, more desirable kinetics of release of TEC, and a higher osteogenic capacity and thus could be an effective alternative to calcium sulfate for local delivery of TEC. PMID:26416858

  18. Comparison of Borate Bioactive Glass and Calcium Sulfate as Implants for the Local Delivery of Teicoplanin in the Treatment of Methicillin-Resistant Staphylococcus aureus-Induced Osteomyelitis in a Rabbit Model.

    PubMed

    Jia, Wei-Tao; Fu, Qiang; Huang, Wen-Hai; Zhang, Chang-Qing; Rahaman, Mohamed N

    2015-12-01

    There is growing interest in biomaterials that can cure bone infection and also regenerate bone. In this study, two groups of implants composed of 10% (wt/wt) teicoplanin (TEC)-loaded borate bioactive glass (designated TBG) or calcium sulfate (TCS) were created and evaluated for their ability to release TEC in vitro and to cure methicillin-resistant Staphylococcus aureus (MRSA)-induced osteomyelitis in a rabbit model. When immersed in phosphate-buffered saline (PBS), both groups of implants provided a sustained release of TEC at a therapeutic level for up to 3 to 4 weeks while they were gradually degraded and converted to hydroxyapatite. The TBG implants showed a longer duration of TEC release and better retention of strength as a function of immersion time in PBS. Infected rabbit tibiae were treated by debridement, followed by implantation of TBG or TCS pellets or intravenous injection with TEC, or were left untreated. Evaluation at 6 weeks postimplantation showed that the animals implanted with TBG or TCS pellets had significantly lower radiological and histological scores, lower rates of MRSA-positive cultures, and lower bacterial loads than those preoperatively and those of animals treated intravenously. The level of bone regeneration was also higher in the defects treated with the TBG pellets. The results showed that local TEC delivery was more effective than intravenous administration for the treatment of MRSA-induced osteomyelitis. Borate glass has the advantages of better mechanical strength, more desirable kinetics of release of TEC, and a higher osteogenic capacity and thus could be an effective alternative to calcium sulfate for local delivery of TEC. PMID:26416858

  19. Chalcogenide glasses for infrared applications: New synthesis routes and rare earth doping

    NASA Astrophysics Data System (ADS)

    Hubert, Mathieu

    shift the optical band gap toward higher wavelengths. A systematic ceramization study emphasizes the difficulty of controlling the crystallization for glasses in the systems GeSe2-Ga2Se3-In2Se 3 and GeSe2-Ga2Se3-PbSe. No crystallization of the In2Se3 and PbSe crystalline phase was obtained. Finally, the possibility of producing rare-earth doped 80GeSe2 -20Ga2Se3 glass-ceramics transparent in the infrared region up to 16 microm is demonstrated. Enhanced photoluminescence intensity and reduced radiative lifetimes are observed with increased crystallinity in these materials.

  20. Spectroscopic studies of copper doped alkaline earth lead zinc phosphate glasses

    NASA Astrophysics Data System (ADS)

    Sastry, S. Sreehari; Rao, B. Rupa Venkateswara

    2014-02-01

    In this paper spectroscopic investigation of Cu2+ doped alkaline earth lead zinc phosphate glasses was done through the spectroscopic techniques like X-ray diffraction, Ultra Violet (UV) absorption Spectroscopy, Electron Paramagnetic Resonance (EPR - X band), Fourier Transform Infra Red (FTIR) and Raman Spectroscopy. Alkaline earth lead zinc phosphate glasses containing 0.1% copper oxide (CuO) were prepared by the melt quenching technique. Spectroscopic studies indicated that there is a greater possibility for the copper ions to exist in Cu2+ state in these glasses. The optical absorption spectra indicated that the absorption peak of Cu2+ is a function of composition. The maxima absorption peak was reported at 862 nm for strontium lead zinc phosphate glass. Bonding parameters were calculated for the optical and EPR data. All these spectral results indicated clearly that there are certain structural changes in the present glass system with different alkaline earth contents. The IR and Raman spectra noticed the breaking of the P-O-P bonds and creating more number of new P-O-Cu bonds.

  1. Novel cerium doped glass-reinforced hydroxyapatite with antibacterial and osteoconductive properties for bone tissue regeneration.

    PubMed

    Morais, D S; Fernandes, S; Gomes, P S; Fernandes, M H; Sampaio, P; Ferraz, M P; Santos, J D; Lopes, M A; Sooraj Hussain, N

    2015-09-01

    The aim of this work was to develop a bioactive bone substitute with an effective antibacterial ability based on a cerium (Ce) doped glass-reinforced hydroxyapatite (GR-HA) composite. Developed composites were physicochemically characterized, using x-ray diffraction (XRD) analysis, SEM, energy dispersive x-ray spectroscopy (EDS), and flexural bending strength (FBS) tests. X-ray photoelectron spectroscopy (XPS) analysis was performed to analyze the oxidation state of Ce in the prepared doped glass. The antimicrobial activity of the composites was evaluated against Staphylococcus aureus, Staphylococcus epidermidis and Pseudomonas aeruginosa; whether the cytocompatibility profile was assayed with human osteoblastic-like cells (Mg-63 cell line). The results revealed that the Ce inclusion in the GR-HA matrix induced the antimicrobial ability of the composite. In addition, Ce-doped materials reported an adequate biological behavior following seeding of osteoblastic populations, by inducing cell adhesion and proliferation. Developed materials were also found to enhance the expression of osteoblastic-related genes. Overall, the developed GR-HA_Ce composite is a prospective candidate to be used within the clinical scenario with a successful performance due to the effective antibacterial properties and capability of enhancing the osteoblastic cell response. PMID:26391473

  2. Synthesis and properties of ZnTe and Eu3+ ion co-doped glass nanocomposites

    NASA Astrophysics Data System (ADS)

    Rahaman Molla, Atiar; Tarafder, Anal; Dey, Chirantan; Karmakar, Basudeb

    2014-10-01

    In this study, ZnTe (II-VI) semiconductor and Eu+3-ion co-doped borosilicate glass has been prepared in the SiO2-K2O-CaO-BaO-B2O3 glass system followed by controlled heat-treatment to produce glass nanocomposites. Glass transition temperature and crystallization peak temperature have been evaluated using DSC analysis. Dilatometric studies were carried out to evaluate thermal expansion co-efficient, glass transition temperature, and dilatometric softening temperature and found to be 10.7 × 10-6/K, 580° C and 628° C, respectively. TEM micrographs demonstrate formation of nano sized crystallites of less than 50 nm. The ZnTe crystal formation also established through selected area electron diffraction (SAED) analysis and high resolution images obtained through TEM studies. With increasing heat treatment time, optical transmission cut-off wavelength (λcut-off) shifted towards higher wavelength. Excitation spectra were recorded by monitoring emission at 613 nm corresponding to the 5D0 → 7F2 transition. An intense 394 nm excitation band corresponding to the 7F0 → 5L6 transition was observed. Emission spectra were then recorded by exciting the glass samples at 394 nm. When the glass is heat-treated for 30 min at 610° C, a 6-fold increase in the intensity of the red emission at 612 nm has been observed, which is attributed to the segregation of Eu3+ ions into the low phonon energy ZnTe crystallites and as the size of the nanocrystals is smaller than the size of the exciton, quantum confinement effect is visible. Further increase in heat-treatment duration led to decrease in luminescence intensity due to the growth of larger size crystals. 5D1 → 7F0 transition is visible only in the samples heat-treated for 30 min and 1 h, which is a characteristic of presence of Eu3+ ions in the low phonon energy ZnTe crystal sites. The micro hardness of the precursor glass and glass nanocomposites was evaluated; base glass shows hardness of 6.7 GPa and hardness of heat

  3. Time Evolution of Radiation-Induced Luminescence in Terbium-Doped Silicate Glass

    NASA Technical Reports Server (NTRS)

    West, Michael S.; Winfree, William P.

    1996-01-01

    A study was made on two commercially available terbium-doped silicate glasses. There is an increased interest in silicate glasses doped with rare-earth ions for use in high-energy particle detection and radiographic applications. These glasses are of interest due to the fact that they can be formed into small fiber sensors; a property that can be used to increase the spatial resolution of a detection system. Following absorption of radiation, the terbium ions become excited and then emit photons via 4f-4f electronic transitions as they relax back to the ground state. The lifetime of these transitions is on the order of milliseconds. A longer decay component lasting on the order of minutes has also been observed. While radiative transitions in the 4f shell of rare-earth ions are generally well understood by the Judd-Olfelt theory, the pr'esence of a longer luminescence decay component is not. Experimental evidence that the long decay component is due, in part, to the thermal release of trapped charge carriers will be presented. In addition, a theoretical model describing the time evolution of the radiation-induced luminescence will be presented.

  4. Spectroscopic investigation of zinc tellurite glasses doped with Yb(3+) and Er(3+) ions.

    PubMed

    Bilir, Gökhan; Kaya, Ayfer; Cinkaya, Hatun; Eryürek, Gönül

    2016-08-01

    This paper presents a detailed spectroscopic investigation of zinc tellurite glasses with the compositions (0.80-x-y) TeO2+(0.20) ZnO+xEr2O3+yYb2O3 (x=0, y=0; x=0.004, y=0; x=0, y=0.05 and x=0.004, y=0.05 per moles). The samples were synthesized by the conventional melt quenching method. The optical absorption and emission measurements were conducted at room temperature to determine the spectral properties of lanthanides doped zinc tellurite glasses and, to study the energy transfer processes between dopant lanthanide ions. The band gap energies for both direct and indirect possible transitions and the Urbach energies were measured from the absorption spectra. The absorption spectra of the samples were analyzed by using the Judd-Ofelt approach. The effect of the ytterbium ions on the emission properties of erbium ions was investigated and the energy transfer processes between dopant ions were studied by measuring the up-conversion emission properties of the materials. The color quality parameters of obtained visible up-conversion emission were also determined as well as possibility of using the Er(3+) glasses as erbium doped fiber amplifiers at 1.55μm in infrared emission region. PMID:27156100

  5. Spectroscopic investigation of zinc tellurite glasses doped with Yb3 + and Er3 + ions

    NASA Astrophysics Data System (ADS)

    Bilir, Gökhan; Kaya, Ayfer; Cinkaya, Hatun; Eryürek, Gönül

    2016-08-01

    This paper presents a detailed spectroscopic investigation of zinc tellurite glasses with the compositions (0.80 - x - y) TeO2 + (0.20) ZnO + xEr2O3 + yYb2O3 (x = 0, y = 0; x = 0.004, y = 0; x = 0, y = 0.05 and x = 0.004, y = 0.05 per moles). The samples were synthesized by the conventional melt quenching method. The optical absorption and emission measurements were conducted at room temperature to determine the spectral properties of lanthanides doped zinc tellurite glasses and, to study the energy transfer processes between dopant lanthanide ions. The band gap energies for both direct and indirect possible transitions and the Urbach energies were measured from the absorption spectra. The absorption spectra of the samples were analyzed by using the Judd-Ofelt approach. The effect of the ytterbium ions on the emission properties of erbium ions was investigated and the energy transfer processes between dopant ions were studied by measuring the up-conversion emission properties of the materials. The color quality parameters of obtained visible up-conversion emission were also determined as well as possibility of using the Er3 + glasses as erbium doped fiber amplifiers at 1.55 μm in infrared emission region.

  6. Light induced dielectric constant of Alumina doped lead silicate glass based on silica sands

    NASA Astrophysics Data System (ADS)

    Diantoro, Markus; Natalia, Desi Ayu; Mufti, Nandang; Hidayat, Arif

    2016-04-01

    Numerous studies on glass ceramic compounds have been conducted intensively. Two major problems to be solved are to simplify the fabrication process by reducing melting temperature as well as improving various properties for various fields of technological application. To control the dielectric constant, the researchers generally use a specific dopant. So far there is no comprehensive study to control the dielectric constant driven by both of dopant and light intensity. In this study it is used Al2O3 dopant to increase the light induced dielectric constant of the glass. The source of silica was taken from local silica sands of Bancar Tuban. The sands were firstly leached using hydrochloric acid to improve the purity of silica which was investigated by means of XRF. Fabricating the glass samples were performed by using melting-glass method. Silica powder was mixed with various ratio of SiO2:Na2CO3:PbO:Al2O3. Subsequently, a mixture of various Al2O3 doped lead silicate glasses were melted at 970°C and directy continued by annealed at 300°C. The samples were investigated by XRD, FTIR, SEM-EDX and measuring dielectric constant was done using dc-capacitance meter with various light intensities. The investigation result of XRD patterns showed that the crystal structures of the samples are amorphous state. The introduction of Al2O3 does not alter the crystal structure, but significantly change the structure of the functional glass bonding PbO-SiO2 which was shown by the FTIR spectra. It was noted that some new peak peaks were exist in the doped samples. Measuring result of dielectricity shows that the dielectric constant of glass increases with the addition of Al2O3. Increasing the light intensity gives rise to increase their dielectric constant in general. A detail observation of the dielectric seen that there are discontinuous step-like of dielectric. Most likely a specific quantization mechanism occurs when glass exposed under light.

  7. A final report on hydrothermal testing of sup 99 Tc-doped glass waste form and waste package components

    SciTech Connect

    Schramke, J.A.; Thomas, L.E.; McKinley, S.G.; Simonson, S.A.; Coles, D.G.; Westinghouse Hanford Co., Richland, WA; Pacific Northwest Lab., Richland, WA )

    1984-07-01

    This document reports the results of four experiments using borosilicate glass doped with the key radionuclide {sup 99}Technicium. The experiments were performed in Dickson rocking autoclaves at 200{degree}C, 30MPa pressure for 3 months. Starting materials consisted of the doped glass (+ undoped borosilicate glass){center dot} in GR-3 groundwater. To simulate various possible interactions among waste package components, the glass-groundwater starting materials were run either alone, or combined with RUE-basalt, or cast steel or both. The Dickson autocalve allowed periodic sampling of the fluid, through which concentrations of dissolved species were monitored. In the glass-only experiment, Tc concentration increased until reaching an apparent steady-state concentration of 55 mg/1 after 1000 hours. In runs with basalt, steel or both, this concentration reached steady-state at three or more orders of magnitude below that. 29 refs., 23 figs., 8 tabs.

  8. Correlation of ion dynamics and structure of superionic tellurite glasses

    SciTech Connect

    Dutta, D.; Ghosh, A.

    2008-01-28

    Ion dynamics and structure of a series of superionic AgI-doped silver tellurite glasses have been investigated in this paper. The composition dependence of the dc conductivity and the activation energy of these glasses has been compared with those of AgI-doped silver phosphate and borate glasses. We have observed that the conductivity increases and the activation energy decreases with increase of AgI content and that the tellurite glasses have higher conductivity than those for phosphate or borate glasses. We have analyzed the ac electrical data in the framework of the power law and the electric modulus formalisms. We have established a correlation between the crossover rate of the mobile silver ions and the rearrangement of the structural units in tellurite glasses. The scaling of the conductivity spectra has been used to interpret the temperature and composition dependence of the relaxation dynamics. Analysis of the dielectric relaxation in the framework of modulus formalism indicates an increase in the ion-ion cooperation in the glass compositions with increasing AgI content.

  9. Optical thermometry based on luminescence behavior of Dy3+-doped transparent LaF3 glass ceramics

    NASA Astrophysics Data System (ADS)

    Bu, Y. Y.; Cheng, S. J.; Wang, X. F.; Yan, X. H.

    2015-11-01

    Dy3+-doped transparent LaF3 glass ceramics were fabricated, and its structures of resulting glass ceramics are studied by the X-ray diffraction and transmission electron microscopy. Optical temperature sensing of the resulting glass ceramics in the temperature range from 298 to 523 K is studied based on the down-conversion luminescence of Dy3+ ion. By using fluorescence intensity ratio method, the 4I15/2 and 4F9/2 of Dy3+ ions are verified as thermally coupled levels. A minimum S R = 1.16 × 10-4 K-1 is obtained at T = 294 K. By doping Eu3+ ion, the overall emission color of Eu3+-Dy3+ co-doped transparent glass ceramics can be tuned from white to yellow with the temperature increase through energy transfer between Eu3+ and Dy3+. Additionally, the thermal stability of the Dy3+ single-doped transparent glass ceramics becomes higher after doping Eu3+ ion.

  10. Sol-gel synthesis and in vitro bioactivity of copper and zinc-doped silicate bioactive glasses and glass-ceramics.

    PubMed

    Bejarano, Julian; Caviedes, Pablo; Palza, Humberto

    2015-03-11

    Metal doping of bioactive glasses based on ternary 60SiO2-36CaO-4P2O5 (58S) and quaternary 60SiO2-25CaO-11Na2O-4P2O5 (NaBG) mol% compositions synthesized using a sol-gel process was analyzed. In particular, the effect of incorporating 1, 5 and 10 mol% of CuO and ZnO (replacing equivalent quantities of CaO) on the texture, in vitro bioactivity, and cytocompatibility of these materials was evaluated. Our results showed that the addition of metal ions can modulate the textural property of the matrix and its crystal structure. Regarding the bioactivity, after soaking in simulated body fluid (SBF) undoped 58S and NaBG glasses developed an apatite surface layer that was reduced in the doped glasses depending on the type of metal and its concentration with Zn displaying the largest inhibitions. Both the ion release from samples and the ion adsorption from the medium depended on the type of matrix with 58S glasses showing the highest values. Pure NaBG glass was more cytocompatible to osteoblast-like cells (SaOS-2) than pure 58S glass as tested by 3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide (MTT) assay. The incorporation of metal ions decreased the cytocompatibility of the glasses depending on their concentration and on the glass matrix doped. Our results show that by changing the glass composition and by adding Cu or Zn, bioactive materials with different textures, bioactivity and cytocompatibility can be synthesized.

  11. Valence band dependence on thermal treatment of gold doped glasses and glass ceramics

    NASA Astrophysics Data System (ADS)

    Radu, T.; Benea, D.; Ciceo-Lucacel, R.; Ponta, O.; Simon, S.

    2012-02-01

    This paper reports x-ray photoemission spectroscopy results regarding the nucleation and growing process of gold nanoparticles (AuNPs) in CaO-SiO2-P2O5 bioactive glasses heat treated at different temperatures. The analysis of the valence band (VB) spectra is discussed in terms of the AuNPs' shape, size, and distribution at the sample surface at different temperatures. Moreover, the theoretical VB photoemission spectra of the investigated samples are presented, and their agreement with experimentally obtained spectra is discussed in detail.

  12. Phosphorus-doped glass proton exchange membranes for low temperature direct methanol fuel cells

    NASA Astrophysics Data System (ADS)

    Prakash, Shruti; Mustain, William E.; Park, SeongHo; Kohl, Paul A.

    Phosphorus-doped silicon dioxide thin films were used as ion exchange membranes in low temperature proton exchange membrane fuel cells. Phosphorus-doped silicon dioxide glass (PSG) was deposited via plasma-enhanced chemical vapor deposition (PECVD). The plasma deposition of PSG films allows for low temperature fabrication that is compatible with current microelectronic industrial processing. SiH 4, PH 3 and N 2O were used as the reactant gases. The effect of plasma deposition parameters, substrate temperature, RF power, and chamber pressure, on the ionic conductivity of the PSG films is elucidated. PSG conductivities as high as 2.54 × 10 -4 S cm -1 were realized, which is 250 times higher than the conductivity of pure SiO 2 films (1 × 10 -6 S cm -1) under identical deposition conditions. The higher conductivity films were deposited at low temperature, moderate pressure, limited reactant gas flow rate, and high RF power.

  13. Ultra-broadband amplification properties of Ni2+-doped glass-ceramics amplifiers.

    PubMed

    Jiang, Chun

    2009-04-13

    The energy level, transition configuration and mathematical model of Ni(2+)-doped glass-ceramics amplifiers are presented for the first time, to the best of one's knowledge. A quasi-three-level system is employed to model the gain and noise characteristics of the doped system, and the rate and power propagation equations of the mathematical model are solved to analyze the effect of the active ion concentration, fiber length, pump power as well as thermal-quenching on the gain spectra. It is shown that our model is in agreement with experimental result, and when excited at longer wavelength, the center of gain spectra of the amplifier red shifts, the ultra-broad band room-temperature gain spectra can cover 1.25-1.65 microm range for amplification of signal in the low-loss windows of the all-wave fiber without absorption peak caused by OH group.

  14. Evidence of a cluster glass-like behavior in Fe-doped ZnO nanoparticles

    NASA Astrophysics Data System (ADS)

    Ramos, J. E.; Montero-Muñoz, M.; Coaquira, J. A. H.; Rodríguez-Páez, J. E.

    2014-05-01

    We report on the study of the structural and magnetic properties of crystalline Fe-doped ZnO nanoparticles with Fe content up to 10% synthesized by a co-precipitation method. The Rietveld analysis indicates that the Fe-doped ZnO nanoparticles are formed in a single phase wurtzite structure. DC magnetization (M) vs. applied magnetic field (H) curves obtained at 5 K show the occurrence of a ferromagnetic behavior. The coercive field and saturation magnetization depend on the Fe content. At room temperature, M vs. H curves show features consistent with a superparamagnetic state of nanoscale system. The temperature dependence of the AC and DC magnetic susceptibilities show features related to the thermal relaxation of the nano-sized particles. From the AC data analysis, a magnetic transition from the superparamagnetic to cluster-glass state is determined.

  15. Higher Fe{sup 2+}/total Fe ratio in iron doped phosphate glass melted by microwave heating

    SciTech Connect

    Mandal, Ashis K.; Sinha, Prasanta K.; Das, Dipankar; Guha, Chandan; Sen, Ranjan

    2015-03-15

    Highlights: • Iron doped phosphate glasses prepared using microwave heating and conventional heating under air and reducing atmosphere. • Presence of iron predominantly in the ferrous oxidation state in all the glasses. • Significant concentrations of iron in the ferrous oxidation state on both octahedral and tetrahedral sites in all the glasses. • Ratio of Fe{sup 2+} with total iron is found higher in microwave prepared glasses in comparison to conventional prepared glasses. - Abstract: Iron doped phosphate glasses containing P{sub 2}O{sub 5}–MgO–ZnO–B{sub 2}O{sub 3}–Al{sub 2}O{sub 3} were melted using conventional resistance heating and microwave heating in air and under reducing atmosphere. All the glasses were characterised by UV–Vis–NIR spectroscopy, Mössbauer spectroscopy, thermogravimetric analysis and wet colorimetry analysis. Mössbauer spectroscopy revealed presence of iron predominantly in the ferrous oxidation state on two different sites in all the glasses. The intensity of the ferrous absorption peaks in UV–Vis–NIR spectrum was found to be more in glasses prepared using microwave radiation compared to the glasses prepared in a resistance heating furnace. Thermogravimetric analysis showed increasing weight gain on heating under oxygen atmosphere for glass corroborating higher ratio of FeO/(FeO + Fe{sub 2}O{sub 3}) in glass melted by direct microwave heating. Wet chemical analysis also substantiated the finding of higher ratio Fe{sup +2}/ΣFe in microwave melted glasses. It was found that iron redox ratio was highest in the glasses prepared in a microwave furnace under reducing atmosphere.

  16. Near infrared luminescence in Yb3+/Ho3+: co-doped germanate glass

    NASA Astrophysics Data System (ADS)

    Kochanowicz, Marcin; Żmojda, Jacek; Miluski, Piotr; Ragin, Tomasz; Jeleń, Piotr; Sitarz, Maciej; Dorosz, Dominik

    2015-12-01

    The near-infrared emission of low phonon (805 cm-1) germanate glasses from GeO2-Ga2O3-BaO system co-doped with 0.7Yb2O3/(0.07-0.7)Ho2O3 ions has been investigated. Luminescence at 2.1 μm corresponding to 5I7 → 5I8 transition in holmium was obtained by energy transfer between Yb3+ and Ho3+ ions. The optimization of the activator content and the concentration ratio were conducted with the purpose of maximizing the efficiency of energy transfer and as a consequence luminescence intensity at 2mm. The highest value of the luminescence intensity was obtained in glass codoped with 0.7Yb2O3/0.15 Ho2O3.

  17. Ultrasonic study on some borosilicate glasses doped with different transition metal oxides

    NASA Astrophysics Data System (ADS)

    Marzouk, S. Y.; Gaafar, M. S.

    2007-12-01

    Longitudinal and shear ultrasonic wave velocities were measured in borosilicate glasses doped with different transition metal oxides (TMOs) (where TMO=NiO, V 2O 5, Fe 2O 3, MnO 2, TiO 2, Cr 2O 3, CoO, CuO) using the pulse echo technique. Measurements were carried out at 4 MHz frequency and at room temperature. Elastic moduli and some other physical parameters such as acoustic impedance, softening temperature, Debye temperature, thermal expansion coefficient, and latent heat of melting have been calculated. Results indicated that these parameters depend upon the TMO modifier, i.e., the ionic radius of the transition metal cation. A quantitative analysis has been carried out, in order to obtain more information about the structure of these glasses, based on bond compression model, and the Makishima and Mackenzie model, i.e., the cation-anion bond of each TMO.

  18. Strong UV absorption and visible luminescence in ytterbium-doped aluminosilicate glass under UV excitation.

    PubMed

    Engholm, M; Norin, L; Aberg, D

    2007-11-15

    A broad visible luminescence band and characteristic IR luminescence of Yb(3+) ions are observed under UV excitation in ytterbium-doped aluminosilicate glass. Samples made under both oxidizing and reducing conditions are analyzed. A strong charge-transfer absorption band in the UV range is observed for glass samples containing ytterbium. Additional absorption bands are observed for the sample made under reducing conditions, which are associated with f-d transitions of divalent ytterbium. The visible luminescence band is attributed to 5d-4f emission from Yb(2+) ions, and the IR luminescence is concluded to originate from a relaxed charge-transfer transition. The findings are important to explain induced optical losses (photodarkening) in high-power fiber lasers. PMID:18026305

  19. Spectroscopic Studies on Eu{sup 3+} Doped Boro-Tellurite Glasses

    SciTech Connect

    Selvaraju, K.; Marimuthu, K.

    2011-07-15

    Eu{sup 3+} doped boro-tellurite glasses have been synthesized and its optical behavior have been studied and reported. The presence of varying tellurium dioxide content results changes in spectroscopic behavoir were explored through UV-VIS, and Luminescence spectra. The bonding parameters have been calculated based on the observed band positions of the absorption spectra. The Judd-Ofelt intensity parameters {Omega}{sub {lambda}} ({lambda} = 2, 4 and 6) have been determined through the luminescence spectra without applying any constraints and the results are presented. The Judd-Ofelt parameters have been used to determine various optical properties corresponding to {sup 5}D{sub 0}{yields}{sup 7}F{sub J}(J = 1,2,3 and 4) transitions of Eu{sup 3+} ions. The varying optical properties of the prepared glasses with the change in tellurium dioxide have been studied and compared with similar studies.

  20. Pulsed laser deposition of Al-doped ZnO films on glass and polycarbonate

    NASA Astrophysics Data System (ADS)

    Tan, Kwan Chu; Lee, Yen Sian; Yap, Seong Ling; Kok, Soon Yie; Nee, Chen Hon; Siew, Wee Ong; Tou, Teck Yong; Yap, Seong Shan

    2014-01-01

    Al-doped ZnO (AZO) films were deposited on glass and polycarbonate (PC) at room temperature by using pulsed Nd:YAG laser at 355 nm. AZO thin films were obtained for both substrates at laser fluences from 2 to 5 J/cm2 in O2 partial pressure of 2.1 Pa. The effects of laser fluence on the structural, electrical, and optical properties of the films were investigated. The films with lowest resistivity and highest transmittance have been obtained at 2 J/cm2. The resistivities were 2.29×10-3 Ω cm for AZO on glass and 1.49×10-3 Ω cm for AZO on PC. With increasing laser fluence, the deposited films have lower crystallinity, higher resistivity, and smaller optical bandgap.

  1. Progress in rare-earth-doped nanocrystalline glass-ceramics for laser cooling

    NASA Astrophysics Data System (ADS)

    Venkata Krishnaiah, Kummara; Ledemi, Yannick; Soares de Lima Filho, Elton; Loranger, Sebastien; Nemova, Galina; Messaddeq, Younes; Kashyap, Raman

    2016-03-01

    Laser cooling with anti-Stokes fluorescencewas predicted by Pringsheim in 1929, but for solids was only demonstrated in 1995. There are many difficulties which have hindered laser assisted cooling, principally the chemical purity of a sample and the availability of suitable hosts. Recent progress has seen the cooled temperature plummet to 93K in Yb:YLF. One of the challenges for laser cooling to become ubiquitous, is incorporating the rare-earthcooling ion in a more easily engineered material, rather than a pure crystalline host. Rare-earth-doped nanocrystalline glass-ceramics were first developed by Wang and Ohwaki for enhanced luminescence and mechanical properties compared to their parent glasses. Our work has focused on creating a nanocrystalline environment for the cooling ion, in an easy to engineer glass. The glasses with composition 30SiO2-15Al2O3-27CdF2-22PbF2-4YF3-2YbF3 (mol%), have been prepared by the conventional melt-quenching technique. By a simple post fabrication thermal treatment, the rare-earth ions are embedded in the crystalline phase within the glass matrix. Nanocrystals with various sizes and rare-earth concentrations have been fabricated and their photoluminescence properties assessed in detail. These materials show close to unity photoluminescence quantum yield (PLQY) when pumped above the band. However, they exhibit strong up-conversion into the blue, characteristic of Tm trace impurity whose presence was confirmed. The purification of the starting materials is underway to reduce the background loss to demonstrate laser cooling. Progress in the development of these nano-glass-ceramics and their experimental characterization will be discussed.

  2. Photoluminescence of Eu³⁺-doped glasses with Cu²⁺ impurities.

    PubMed

    Jiménez, José A

    2015-06-15

    Glasses activated with Eu(3+) ions are attractive as luminescent materials for various photonic applications. Co-doping with copper has been proposed for enhancing material optical properties, but the quenching effect of Cu(2+) impurities on Eu(3+) emission in glass remains largely unexplored. In this work, Eu2O3/CuO-containing barium-phosphate glasses have been prepared by the melt-quench method, and the Eu(3+) photoluminescence (PL) quenching resulting from Eu(3+)→Cu(2+) energy transfer was evaluated. Optical absorption spectroscopy showed that with the increase in CuO concentration the Cu(2+) absorption band resonant with Eu(3+) emission (e.g. (5)D0→(7)F2 transition around 615 nm) developed steadily. As a result, Eu(3+) PL was progressively quenched. Evaluation of the quenching constants as a function of temperature in the 298-673K range showed differences basically within experimental error, consistent with a resonant transfer and lack of phonon-assisted processes. Moreover, analysis of the Eu(3+) emission decay dynamics revealed a strong correlation between the decay rates and Cu(2+) impurity levels. Results imply that for practical applications the levels of Cu(2+) in Eu(3+)/Cu(+)-activated glasses should be reduced if not removed as these will significantly limit device efficiency. PMID:25797222

  3. Antibacterial and bioactive composite bone cements containing surface silver-doped glass particles.

    PubMed

    Miola, Marta; Fucale, Giacomo; Maina, Giovanni; Verné, Enrica

    2015-09-01

    A bioactive silica-based glass powder (SBA2) was doped with silver (Ag(+)) ions by means of an ion-exchange process. Scanning electron microscopy (SEM), energy dispersion spectrometry (EDS) and x-ray diffraction (XRD) evidenced that the glass powder was enriched with Ag(+) ions. However, a small amount of Ag2CO3 precipitated with increased Ag concentrations in the exchange solution. The minimum inhibitory concentration (MIC) and the minimum bactericidal concentration (MBC) of Ag-SBA2 towards Staphylococcus aureus were also evaluated and were respectively 0.05 mg ml(-1) and 0.2 mg ml(-1). Subsequently, Ag-SBA2 glass was used as filler (30%wt) in a commercial formulation of bone cement (Simplex(™) P) in order to impart both antibacterial and bioactive properties. The composite bone cement was investigated in terms of morphology (using SEM) and composition (using EDS); the glass powder was well dispersed and exposed on the cement surface. Bioactivity tests in simulated body fluid (SBF) evidenced the precipitation of hydroxyapatite on sample surfaces. Composite cement demonstrated antibacterial properties and a compressive strength comparable to the commercial formulation.

  4. Analysis of thermal and structural properties of germanate glasses co-doped with Yb3+/Tb3+ ions

    NASA Astrophysics Data System (ADS)

    Zmojda, J.; Kochanowicz, M.; Miluski, P.; Dorosz, D.; Jelen, P.; Sitarz, M.

    2014-10-01

    In the work the new glass compositions in the GeO2-GaO-BaO system have been prepared and thermal, structural properties of in germanate glasses co-doped with Yb3+/Tb3+ions were studied. Glasses were obtained by conventional high-temperature melt-quenching technique. The study of the crystallization kinetics processes of glasses co-doped with 0.7Yb2O3:0.7Tb2O3 was performed with DSC measurements. The activation energies have been calculated using Freedman analysis and verified with the Flynn-Wall-Ozawa method. In this order, the DSC curves have been registered with different heating rates, between 5 and 15 degrees/min. The structure of fabricated glasses has been studied by infrared and Raman spectroscopes. The effect of heat treatment on the structural properties was determined. In all glass samples the dominated infrared absorbance band at 800 cm-1 corresponds to asymmetric stretching motions of GeO4 tetrahedra containing bridging (Ge-O(Ge)) and non-bridging (Ge-O-) oxygens. Additionally, the influence of heat treatment on the luminescent properties was evaluated. Strong luminescence at 489, 543, 586 and 621 nm corresponding to 5D4 → 7FJ (J = 6, 5, 4, 3) transitions was measured. The highest upconversion emission intensity was obtained in the germanate glass co-doped with 0.7Yb2O3/0.7Tb2O3.

  5. Optical band gap and structural study on GeO2- and Y2O3-doped barium aluminoborate glasses

    NASA Astrophysics Data System (ADS)

    Marzouk, M. A.; Fayad, A. M.

    2016-10-01

    A series of barium borate-based glasses containing Al2O3, GeO2 and Y2O3 were prepared by conventional method of glass melting and annealing. The prepared glasses were investigated through optical, FTIR, density and molar volume measurements. The optical absorption spectra reveal three characteristic UV absorption peaks at about 213, 240 and 308 nm. The optical absorption measurements were used to estimate direct and indirect transition of optical band gap ( E opt), Urbach energy (Δ E) and the refractive index ( n).Values of the optical parameters are found to be related to the structural changes that are taking place in the prepared glasses. The deconvoluted vibrational modes identified in the IR spectrum illustrated the conversion of triangular BO3 structural units to BO4 tetrahedral units with the addition of GeO2 or Y2O3. The formation of non-bridging oxygen atoms is assumed to lead to provide some favorable properties, mainly the optical properties and semiconducting behavior of the prepared glassy samples. Density and molar volume data are found to be dependent on the rigidity of the glass network.

  6. Suppression mechanism of radiation-induced darkening by Ce doping in Al/Yb/Ce-doped silica glasses: Evidence from optical spectroscopy, EPR and XPS analyses

    NASA Astrophysics Data System (ADS)

    Shao, Chongyun; Xu, Wenbin; Ollier, Nadege; Guzik, Malgorzata; Boulon, Georges; Yu, Lu; Zhang, Lei; Yu, Chunlei; Wang, Shikai; Hu, Lili

    2016-10-01

    Yb3+/Al3+ co-doped silica glasses with different Ce2O3 contents were prepared using the sol-gel method combined with high-temperature sintering. Changes in refractive index, absorption, emission and fluorescence lifetime of these glasses caused by X-ray irradiation were recorded and analyzed systematically. It is found that co-doping with certain amount of Ce could greatly improve the radiation resistance without evident negative effects on the basic optical properties of the Yb3+ ions in the near-infrared region. The nature of the radiation-induced color centres and the mechanism by which Ce prevented the formation of these centres were studied using optical absorption, electron paramagnetic resonance (EPR), and X-ray photoelectron spectroscopy (XPS) methods. Direct evidence confirmed that trapped electron centres (Yb2+/Si-E'/Al-E') and trapped hole centres (Al-OHCs) were effectively inhibited by Ce doping, which was correlated to the coexistence of the redox couple Ce3+/Ce4+ in the glasses. These results are helpful to understand the micro-structural origin and the suppression mechanism by Ce co-doping of the photodarkening effect in Yb3+-doped silica fibers.

  7. Thermal lens study of thermo-optical properties and concentration quenching of Er3+-doped lead pyrophosphate based glasses

    SciTech Connect

    Santos, C. C.; Rocha, U.; Guedes, Ilde; Vermelho, M. V. D.; Boatner, Lynn A; Jacinto, C.

    2012-01-01

    In this work, we have used the thermal lens technique combined with conventional spectroscopy to characterize the thermo-optical properties of Er3+-doped lead pyrophosphate-based glasses. More precisely, we have investigated and quantified experimentally the fluorescence quantum efficiencies of the Er3+ levels, and we describe the role of concentration quenching effects. The fluorescence quantum efficiency of the 4I13/2 level is very high when compared to other phosphate glasses, while that of the green-coupled levels is very small. Other important photonic materials parameters, such as the thermal diffusivity and temperature coefficient of the optical path length change, were obtained and compared with those of other glass systems. The cumulative results obtained here for the Er-doped lead pyrophosphate glass show that this material is a good candidate for photonic applications with a characteristic Er3+ infrared emission around 1550 nm.

  8. Luminescence properties of Eu3+-doped SiO2-LiYF4 glass-ceramic microrods

    NASA Astrophysics Data System (ADS)

    Secu, C. E.; Secu, M.

    2015-09-01

    Photoluminescence properties of the glass-ceramics microrods containing Eu3+-doped LiYF4 nanocrystals have been studied and characterized. Judd-Ofelt parameters and quantum efficiency has been computed from luminescence spectra and discussed by comparison to the glass ceramic bulk and pellet. The radiative decay rate Arad is higher in the glass ceramic rods (221 s-1) than in the glass ceramic bulk (130 s-1) but the quantum efficiency computed is very low (21%) compared to the glass-ceramic bulk (97%). There are effective non-radiative decay channels that might be related to an influence of the dimensional constraints imposed by the membrane pores during xerogel formation and subsequent glass ceramization.

  9. Helical core optical fibre made of Nd3+/Yb3+-doped oxyfluoride silicate glass

    NASA Astrophysics Data System (ADS)

    Dorosz, D.; Kochanowicz, M.; Zmojda, J.; Dorosz, J.

    2010-05-01

    The properties of helical-core optical fibre made by authors from Nd3+/Yb3+-doped oxyfluoride silicate glass are presented. The construction and forming conditions of the helical-core optical fibre enabled to obtain the helix pitch from several mm and the off-set ranging from 10 μm to 200 μm. The paper also presents optimisation of Nd3+/Yb3+ ratio to enhance the emission bandwidth at 1 μm. In consequence of matching the values of the emission cross-section σem(Nd)and the absorption cross-section σabs(Yb) in the glass doped with 0.15Nd3+:0.45Yb3+ a broad (Δλ = 100nm) luminescence band in the vicinity of 1μm was obtained, which was the result of overlapping emission transitions: 2F5/2-->2F7/2 in ytterbium and 4F3/2-->4I11/2 in neodymium.

  10. Optical and spectroscopic characterization of Er3+-Yb3+co-doped tellurite glasses and fibers

    NASA Astrophysics Data System (ADS)

    Narro-García, R.; Desirena, H.; Chillcce, E. F.; Barbosa, L. C.; Rodriguez, E.; De la Rosa, E.

    2014-04-01

    Optical and spectroscopic properties of Er3+-Yb3+ co-doped TeO2-WO3-Nb2O5-Na2O-Al2O3 glasses and fibers were investigated. Emission spectra and fluorescence lifetimes of 4I13/2 level of Er3+ion as a function of rare earth concentration and fiber length were measured in glasses. Results show that the self-absorption effect broadens the spectral bandwidth of 4I13/2→4I15/2 transition and lengthens the lifetime significantly from 3.5 to 4.6 ms. Fibers were fabricated by the rod-in-tube technique using a Heathway drawing tower. The emission power of these Er3+-Yb3+ co-doped Step Index Tellurite Fibers (SITFs; lengths varying from 2 to 60 cm) were generated by a 980 nm diode laser pump and then the emission power spectra were acquired with an OSA. The maximum emission power spectra, within the 1530-1560 nm region, were observed for fiber lengths ranging from 3 to 6 cm. The highest bandwidth obtained was 108 nm for 8 cm fiber length around 1.53 µm.

  11. Comparative investigation on the spectroscopic properties of Pr³⁺-doped boro-phosphate, boro-germo-silicate and tellurite glasses.

    PubMed

    Zhang, Liaolin; Dong, Guoping; Peng, Mingying; Qiu, Jianrong

    2012-07-01

    We report on the spectroscopic properties of Pr(3+)-doped boro-phosphate, boro-germo-silicate and tellurite glasses. The stimulated absorption and emission cross sections were estimated. Only one emission at 596 nm and 605 nm is observed in Pr(3+)-doped boro-phosphate and boro-germo-silicate glasses, respectively, while three emissions at 605 nm, 612 nm and 645 nm are observed in Pr(3+)-doped tellurite glass when excited at 467 nm. The fluorescence lifetime at 600 nm in Pr(3+)-doped boro-phosphate, boro-germo-silicate and tellurite glasses is 137 μs, 73 μs and 51 μs, respectively. The emissions from Pr(3+)-doped boro-phosphate, boro-germo-silicate and tellurite glasses show different decay behaviors and can be well explained by multiphonon relaxation theory.

  12. Investigations on spectroscopic properties of Pr3+ and Nd3+ doped zinc-alumino-sodium-phosphate (ZANP) glasses

    NASA Astrophysics Data System (ADS)

    Brahmachary, K.; Rajesh, D.; Babu, S.; Ratnakaram, Y. C.

    2014-05-01

    Zinc-alumino-sodium-phosphate (ZANP) glasses doped with rare earth metal ions (Nd3+ and Pr3+) with different concentrations (0.5, 1.0, 1.5, 2.0 and 2.5 mol%) were prepared by melt quenching technique. X-ray diffraction, SEM with EDS, Raman spectra, FTIR-spectra, DTA, absorption and luminescence spectra were recorded at room temperature for all the glass matrices and analyzed. X-ray diffraction profiles and SEM images confirmed the amorphous nature of the glass samples. The EDS spectrum of doped and undoped glasses reveals the chemical composition present in them. Structural information of these glass matrices was provided by FTIR and Raman spectra. From DTA analysis, the glass transition temperature (Tg) and crystallization temperature (Tc) were determined. From the absorption spectra, the Judd-Ofelt (J-O) parameters, Ωλ (λ = 2, 4 and 6) and other radiative properties like transition probabilities (AR), radiative lifetimes (τR) and branching ratios (βR) were evaluated. Branching ratios and stimulated emission cross-sections show that 4F3/2 → 4I11/2 transition of Nd3+ ion and 3P0 → 3H4 transition of Pr3+ ion of the glasses under investigation have strong emission at 1060 and 490 nm respectively. The results obtained were compared with reports on similar glasses.

  13. Dy3+-doped tellurite based tungsten-zirconium glasses: Spectroscopic study

    NASA Astrophysics Data System (ADS)

    Venkataiah, G.; Jayasankar, C. K.

    2015-03-01

    Tellurite based tungsten zirconium glasses-doped with trivalent dysprosium (Dy3+) ions (TWZDy) have been prepared by conventional melt-quenching technique and characterized through thermal, structural and spectroscopic measurements. XRD pattern of the glass confirms its amorphous nature. The functional groups of the TeO3 and TeO4 units along with Wsbnd O- and Zrsbnd O vibrations have been identified from Fourier transform infrared spectrum. The energy level analysis has been carried out by using the parametric free-ion Hamiltonian model. Judd-Ofelt theory has been used to explore the spectral intensities of Dy3+ ions in the present glass system. From the emission spectra, the emission intensities increases from 0.05 to 1.0 mol% of Dy3+ ion and then decreases for higher concentrations due to energy transfer between Dy3+ ions. The higher value of peak stimulated emission cross-section (40.46 × 10-22 cm2), noticed for 4F9/2 → 6H13/2 transition, is comparable with other reported Dy3+ systems. The TWZDy glasses emit intense yellowish-white color (x = 0.32; y = 0.44) which is nearer to standard white light zone. The decay curves exhibit single exponential nature at lower concentrations (⩽0.1 mol%) and turns into non-exponential (⩾0.5 mol%) due to energy transfer processes. In order to unravel the energy transfer process the non-exponential decay curves have been fitted to Inokuti-Hirayama (IH) model with S = 6. The analyses of the results indicate that the present TWZDy glasses are suitable for luminescent display device applications as well as for white light generation.

  14. Structural and luminescence studies on Dy3+ doped lead boro-telluro-phosphate glasses

    NASA Astrophysics Data System (ADS)

    Selvi, S.; Venkataiah, G.; Arunkumar, S.; Muralidharan, G.; Marimuthu, K.

    2014-12-01

    This paper reports results obtained on the structural and luminescence properties of Dy3+doped lead boro-telluro-phosphate glasses prepared following the melt quenching technique. FTIR spectra exhibit the presence of B-O vibrations, P-O-P symmetric vibrations and Te-O stretching modes of TeO3 and TeO6 units. The metal-ligand bond was identified through UV-vis-NIR absorption spectra and to determine the band tailing parameter, direct and indirect band gap energy of the prepared glasses. The Judd-Ofelt (JO) intensity parameters (Ω2, Ω4 and Ω6), experimental and theoretical oscillator strengths were also determined and reported. Luminescence measurements were made to determine the transition probability (A), stimulated emission cross-section (σPE) and branching ratio (βR) for the transitions that include 4F9/2→6H11/2, 6H13/2 and 6H15/2 bands. The effect of Dy3+ ion concentration on the intensity ratio of yellow to blue emission bands has also been studied and reported. The lifetime corresponding to the 4F9/2 level of the title glasses has been found to decrease with the increase in Dy3+ ion concentration. The chromaticity coordinates (x,y) have been estimated from the luminescence spectra and the suitability of title glasses for white light applications has been analyzed using CIE chromaticity diagram. The variation of optical properties with the concentration of dysprosium oxide content in the glasses have been studied and reported.

  15. Making Glasses Conduct: Electrochemical Doping of Redox-Active Polymer Thin Films

    NASA Astrophysics Data System (ADS)

    Boudouris, Bryan

    Optoelectronically-active macromolecules have been established as promising materials in myriad organic electronic applications (e.g., organic field-effect transistors (OFETs) and organic photovoltaic (OPV) devices). To date, however, the majority of the work surrounding these materials has focused on materials with a great deal of conjugation along their macromolecular backbones and with varying degrees of crystalline structure. Here, we describe an emerging class of macromolecular charge conductors, radical polymers, that: (1) do not contain conjugation and (2) are completely amorphous glasses. Radical polymers contain non-conjugated macromolecular backbones and stable radical sites along the side chains of the electronically-active materials. In contrast to conjugated polymer systems, these materials conduct charge in the solid state through oxidation-reduction (redox) reactions along these pendant groups. Specifically, we demonstrate that controlling the chemical functionality of the pendant groups and the molecular mobility of the macromolecular backbones significantly impacts the charge transport ability of the pristine (i.e., not doped) radical polymers species. Through proper control of these crucial parameters, we show that radical polymers can have electrical conductivity and charge mobility values on par with commonly-used conjugated polymers. Importantly, we also highlight the ability to dope radical polymers with redox-active small molecule species. This doping, in turn, increases the electrical conductivity of the glassy radical polymer thin films in a manner akin to what is observed in traditional conjugated polymer systems. In this way, we establish a means by which to fabricate optically-transparent and colorless thin film glasses capable of conducting charge in a rather rapid manner. We anticipate that these fundamental insights will prove crucial in developing new transparent conducting layers for future electronic applications.

  16. Effect of Ga2O3 on the spectroscopic properties of erbium-doped boro-bismuth glasses.

    PubMed

    Ling, Zhou; Ya-Xun, Zhou; Shi-Xun, Dai; Tie-Feng, Xu; Qiu-Hua, Nie; Xiang, Shen

    2007-11-01

    The spectroscopic properties and thermal stability of Er3+-doped Bi2O3-B2O3-Ga2O3 glasses are investigated experimentally. The effect of Ga2O3 content on absorption spectra, the Judd-Ofelt parameters Omega t (t=2, 4, 6), fluorescence spectra and the lifetimes of Er3+:4I 13/2 level are also investigated, and the stimulated emission cross-section is calculated from McCumber theory. With the increasing of Ga2O3 content in the glass composition, the Omega t (t=2, 4, 6) parameters, fluorescence full width at half maximum (FWHM) and the 4I 13/2 lifetimes of Er3+ first increase, reach its maximum at Ga2O3=8 mol.%, and then decrease. The results show that Er3+-doped 50Bi2O3-42B2O3-8Ga2O3 glass has the broadest FWHM (81nm) and large stimulated emission cross-section (1.03 x1 0(-20)cm2) in these glass samples. Compared with other glass hosts, the gain bandwidth properties of Er+3-doped Bi2O3-B2O3-Ga2O3 glass is better than tellurite, silicate, phosphate and germante glasses. In addition, the lifetime of 4I 13/2 level of Er(3+) in bismuth-based glass, compared with those in other glasses, is relative low due to the high-phonon energy of the B-O bond, the large refractive index of the host and the existence of OH* in the glass. At the same time, the glass thermal stability is improved in which the substitution of Ga2O3 for B2O3 strengthens the network structure. The suitability of bismuth-based glass as a host for a Er3+-doped broadband amplifier and its advantages over other glass hosts are also discussed. PMID:17350330

  17. Differentiation of human mesenchymal stem cells on niobium-doped fluorapatite glass-ceramics

    PubMed Central

    Kushwaha, Meenakshi; Pan, Xueliang; Holloway, Julie A.; Denry, Isabelle L.

    2011-01-01

    Objectives Our goal was to characterize the response of human mesenchymal stem cells (hMSCs) to a niobium-doped fluorapatite-based glass-ceramic (FAp). Methods The glass was prepared by twice melting at 1525°C for 3h, and cast into cylindrical ingots later sectioned into discs and heat-treated to promote crystallization of fluorapatite submicrometer crystals. Tissue culture polystyrene (TCP) was used as control. The surface of the FAp discs was either left as-heat treated, ground or etched. Initial cell attachment was assessed at 3h. Proliferation and alkaline phosphatase (ALP) expression data was collected at days 1, 4, and 8. Cell morphology was examined using SEM, at days 2 and 4. Mineralization was evaluated by Alizarin Red staining and SEM. Results Initial cell attachment on as heat-treated, etched, or ground surfaces was similar to that of the positive control group (p>0.05). The percentage of area covered by living cells increased significantly on as heat-treated, etched, or ground surfaces between days 1 and 8 (p<0.05). There was no significant difference amongst groups in cell coverage at day 8, compared to TCP control. SEM revealed well spread polygonal cells with numerous filopodia, either attached to the ceramic surface or connected to neighboring cells. ALP expression at day 8 was significantly higher in osteogenic media compared to growth media on both FAp and control. FAp discs stained positively with alizarin red and calcium-rich mineralized granules associated with fibrils were observed by SEM at day 35. Significance hMSCs displayed excellent attachment, proliferation, and differentiation on niobium-doped FAp glass-ceramic. PMID:22078764

  18. Engineering of the extraordinary optical transmission of metallic gratings via Er3+-doped tellurite glass

    NASA Astrophysics Data System (ADS)

    Silva, O. B.; Rivera, Victor A. G.; Marega, E.

    2015-03-01

    Although the properties of extraordinary optical transmission (EOT) due surface plasmon polariton (SPP), which are coupled in metallic slits have been widely studied in the last two decades, their influence on the absorption and transmission spectra from their dielectric substrates has not been deserved the same attention. The choice of a good substrate for implementation not just for gratings, but also for other devices, it is extremely important in order to achieve great applications of the EOT. Good candidates to replace the conventional semiconductor based substrates are the rare earth ions (REI) doped glasses. The specific case of Erbium ions and its implementation into glasses for the fabrication of fiber optics, as Erbium doped fiber amplifiers (EDFA). The transmission observed through the plasmonic nanostructures is elucidated considering the following effects: (i) white light absorption by the Er3+ ions, (ii) coupling between the light and the nanostructure via the creation of surface plasmon polariton where the wavelengths with minimums transmission corresponds to the 4I15/2 → [2H9/2, 4F3/2, 4F5/2, 4F7/2, 2H11/2, 4S3/2, 4F9/2] absorption levels the Er3+, which propagates through the slits, and, finally, (iii) the Er3+ transmission intensity and the spectral shape -symmetry depend on the nature of metallic film and the number of slits constituting the arrays, for which the resonant properties are strongly affected. Furthermore, in order to compare the influence of substrate in the transmission properties, we also performed the same measurements on slit arrays fabricated on the BK 7 glass.

  19. Highly Tm(3+) doped germanate glass and its single mode fiber for 2.0 μm laser.

    PubMed

    Wen, Xin; Tang, Guowu; Yang, Qi; Chen, Xiaodong; Qian, Qi; Zhang, Qinyuan; Yang, Zhongmin

    2016-01-01

    Highly Tm(3+) doped optical fibers are urgently desirable for 2.0 μm compact single-frequency fiber laser and high-repetition-rate mode-locked fiber laser. Here, we systematically investigated the optical parameters, energy transfer processes and thermal properties of Tm(3+) doped barium gallo-germanate (BGG) glasses. Highly Tm(3+) doped BGG glass single mode (SM) fibers were fabricated by the rod-in-tube technique. The Tm(3+) doping concentration reaches 7.6 × 10(20) ions/cm(3), being the reported highest level in Tm(3+) doped BGG SM fibers. Using ultra short (1.6 cm) as-drawn highly Tm(3+) doped BGG SM fiber, a single-frequency fiber laser at 1.95 μm has been demonstrated with a maximum output power of 35 mW when in-band pumped by a home-made 1568 nm fiber laser. Additionally, a multilongitudinal-mode fiber laser at 1.95 μm has also been achieved in a 10 cm long as-drawn active fiber, yielding a maximum laser output power of 165 mW and a slope efficiency of 17%. The results confirm that the as-drawn highly Tm(3+) doped BGG SM fibers are promising in applications that require high gain and high power from a short piece of active optical fiber. PMID:26828920

  20. Highly Tm3+ doped germanate glass and its single mode fiber for 2.0 μm laser

    NASA Astrophysics Data System (ADS)

    Wen, Xin; Tang, Guowu; Yang, Qi; Chen, Xiaodong; Qian, Qi; Zhang, Qinyuan; Yang, Zhongmin

    2016-02-01

    Highly Tm3+ doped optical fibers are urgently desirable for 2.0 μm compact single-frequency fiber laser and high-repetition-rate mode-locked fiber laser. Here, we systematically investigated the optical parameters, energy transfer processes and thermal properties of Tm3+ doped barium gallo-germanate (BGG) glasses. Highly Tm3+ doped BGG glass single mode (SM) fibers were fabricated by the rod-in-tube technique. The Tm3+ doping concentration reaches 7.6 × 1020 ions/cm3, being the reported highest level in Tm3+ doped BGG SM fibers. Using ultra short (1.6 cm) as-drawn highly Tm3+ doped BGG SM fiber, a single-frequency fiber laser at 1.95 μm has been demonstrated with a maximum output power of 35 mW when in-band pumped by a home-made 1568 nm fiber laser. Additionally, a multilongitudinal-mode fiber laser at 1.95 μm has also been achieved in a 10 cm long as-drawn active fiber, yielding a maximum laser output power of 165 mW and a slope efficiency of 17%. The results confirm that the as-drawn highly Tm3+ doped BGG SM fibers are promising in applications that require high gain and high power from a short piece of active optical fiber.

  1. Highly Tm3+ doped germanate glass and its single mode fiber for 2.0 μm laser

    PubMed Central

    Wen, Xin; Tang, Guowu; Yang, Qi; Chen, Xiaodong; Qian, Qi; Zhang, Qinyuan; Yang, Zhongmin

    2016-01-01

    Highly Tm3+ doped optical fibers are urgently desirable for 2.0 μm compact single-frequency fiber laser and high-repetition-rate mode-locked fiber laser. Here, we systematically investigated the optical parameters, energy transfer processes and thermal properties of Tm3+ doped barium gallo-germanate (BGG) glasses. Highly Tm3+ doped BGG glass single mode (SM) fibers were fabricated by the rod-in-tube technique. The Tm3+ doping concentration reaches 7.6 × 1020 ions/cm3, being the reported highest level in Tm3+ doped BGG SM fibers. Using ultra short (1.6 cm) as-drawn highly Tm3+ doped BGG SM fiber, a single-frequency fiber laser at 1.95 μm has been demonstrated with a maximum output power of 35 mW when in-band pumped by a home-made 1568 nm fiber laser. Additionally, a multilongitudinal-mode fiber laser at 1.95 μm has also been achieved in a 10 cm long as-drawn active fiber, yielding a maximum laser output power of 165 mW and a slope efficiency of 17%. The results confirm that the as-drawn highly Tm3+ doped BGG SM fibers are promising in applications that require high gain and high power from a short piece of active optical fiber. PMID:26828920

  2. Electrical and optical properties of Ti doped ZnO films grown on glass substrate by atomic layer deposition

    SciTech Connect

    Wan, Zhixin; Kwack, Won-Sub; Lee, Woo-Jae; Jang, Seung-II; Kim, Hye-Ri; Kim, Jin-Woong; Jung, Kang-Won; Min, Won-Ja; Yu, Kyu-Sang; Park, Sung-Hun; Yun, Eun-Young; Kim, Jin-Hyock; Kwon, Se-Hun

    2014-09-15

    Highlights: • Ti doped ZnO films were prepared on Corning XG glass substrate by ALD. • The electrical properties and optical properties were systematically investigated. • An optimized Ti doped ZnO films had low resistivity and excellent optical transmittance. - Abstract: Titanium doped zinc oxide (Ti doped ZnO) films were prepared by atomic layer deposition methods at a deposition temperature of 200 °C. The Ti content in Ti doped ZnO films was varied from 5.08 at.% to 15.02 at.%. X-ray diffraction results indicated that the crystallinity of the Ti doped ZnO films had degraded with increasing Ti content. Transmission electron microscopy was used to investigate the microstructural evolution of the Ti doped ZnO films, showing that both the grain size and crystallinity reduced with increasing Ti content. The electrical resistivity of the Ti doped ZnO films showed a minimum value of 1.6 × 10{sup −3} Ω cm with the Ti content of 6.20 at.%. Furthermore, the Ti doped ZnO films exhibited excellent transmittance.

  3. Semiconductor-doped glass saturable absorbers for near-infrared solid-state lasers

    NASA Astrophysics Data System (ADS)

    Malyarevich, A. M.; Yumashev, K. V.; Lipovskii, A. A.

    2008-04-01

    A survey of results on use of semiconductor-doped glass saturable absorbers for near-infrared passively mode-locked and Q-switched solid-state lasers is presented. Nanosized semiconductor particles (quantum dots) belong to quantum confined systems where motion of an electron and a hole is defined by the finite size of the nanoparticle. Dependence of the excitonic transition energy on the QDs size provides the possibility to tune the absorption of the glasses embedded with such particles to wavelength of specific light source. IV-VI semiconductor QDs (PbS, PbSe) are of interest for IR application due to their narrow band gap and large exciton Bohr radii. These allow for exciton absorption band at the wavelength through 1-3μm. Nonlinear optical properties of PbS, PbSe, and CuxSe nanoparticles embedded in glass matrices necessary for saturable absorber applications are analyzed. It is shown that these materials can be efficiently used for passive mode locking and Q switching of solid-state lasers based on Nd3+, Yb3+, Cr4+, Tm3+, and Ho3+ ions emitting through 1-2.1μm spectral range.

  4. Effect of crystallization heat treatment on the microstructure of niobium-doped fluorapatite glass-ceramics.

    PubMed

    Denry, I; Holloway, J A; Gupta, P K

    2012-07-01

    Our goal was to study the effect of heat treatment temperature and heating rate on the microstructure and crystalline phases and assess the domain of existence of submicrometer fluorapatite crystals in niobium-doped fluorapatite glass-ceramics for biomedical applications. Glass-ceramic specimens were prepared by casting and heat treatment between 700 and 1200°C using a fast or a slow heating rate. The microstructure was characterized by atomic force microscopy and scanning electron microscopy. Crystalline phases were analyzed by x-ray diffraction. AFM of the as-cast glass revealed that amorphous phase separation occurred in this system. XRD confirmed the presence of fluorapatite in all specimens, together with forsterite and enstatite at higher temperatures. Both heating rate and heat treatment temperature strongly influenced microstructure and crystallinity. A dual microstructure with submicrometer fluorapatite crystals and polygonal forsterite crystals was obtained when slow heating rates and crystallization temperatures between 950 and 1100°C were used. Needle-shaped fluorapatite crystals appeared after heat treatment above 1100°C. Fast heating rates led to an increase in crystal size. Heat treatment temperatures should remain below 1100°C, together with slow heating rates, to prevent crystal dissolution, and preserve a dual microstructure of finely dispersed submicrometer crystals without growth of needle-shaped crystals.

  5. Photo-acoustic spectroscopy and quantum efficiency of Yb{sup 3+} doped alumino silicate glasses

    SciTech Connect

    Kuhn, Stefan Tiegel, Mirko; Herrmann, Andreas; Rüssel, Christian; Engel, Sebastian; Wenisch, Christoph; Gräf, Stephan; Müller, Frank A.; Körner, Jörg; Seifert, Reinhard; Yue, Fangxin; Klöpfel, Diethardt; Hein, Joachim; Kaluza, Malte C.

    2015-09-14

    In this contribution, we analyze the effect of several preparation methods of Yb{sup 3+} doped alumino silicate glasses on their quantum efficiency by using photo-acoustic measurements in comparison to standard measurement methods including the determination via the fluorescence lifetime and an integrating sphere setup. The preparation methods focused on decreasing the OH concentration by means of fluorine-substitution and/or applying dry melting atmospheres, which led to an increase in the measured fluorescence lifetime. However, it was found that the influence of these methods on radiative properties such as the measured fluorescence lifetime alone does not per se give exact information about the actual quantum efficiency of the sample. The determination of the quantum efficiency by means of fluorescence lifetime shows inaccuracies when refractive index changing elements such as fluorine are incorporated into the glass. Since fluorine not only eliminates OH from the glass but also increases the “intrinsic” radiative fluorescence lifetime, which is needed to calculate the quantum efficiency, it is difficult to separate lifetime quenching from purely radiative effects. The approach used in this contribution offers a possibility to disentangle radiative from non-radiative properties which is not possible by using fluorescence lifetime measurements alone and allows an accurate determination of the quantum efficiency of a given sample. The comparative determination by an integrating sphere setup leads to the well-known problem of reabsorption which embodies itself in the measurement of too low quantum efficiencies, especially for samples with small quantum efficiencies.

  6. Optical properties of Dy3+ doped bismuth boro-tellurite glasses for WLED applications

    NASA Astrophysics Data System (ADS)

    Karthikeyan, P.; Marimuthu, K.

    2016-05-01

    The Dy3+ doped bismuth boro-tellurite glasses with the chemical composition (79.5-x) B2O3+xTeO2+10Bi2O3+10PbF2+0.5Dy2O3 (where x = 10, 20, 30 and 40 in wt%) have been prepared by melt quenching technique. The optical properties of the prepared glasses have been studied through absorption and emission spectral measurements. The bonding parameters, optical band gap energy, Urbach's energy and Judd-Ofelt (JO) intensity parameters (Ωλ, λ = 2, 4 and 6) were calculated from the absorption spectra. The radiative properties like transition probability (A), stimulated emission cross-section (σPE) and branching ratios (βR) were calculated from the emission spectra using JO theory. The strong emissions in the visible region, large stimulated emission cross-section and higher branching ratio values observed for the title glasses are found to be suitable for lasers and WLED applications.

  7. Effect of crystallization heat treatment on the microstructure of niobium-doped fluorapatite glass-ceramics

    PubMed Central

    Denry, I.; Holloway, J.A.; Gupta, P.K.

    2012-01-01

    Our goal was to study the effect of heat treatment temperature and heating rate on the microstructure and crystalline phases and assess the domain of existence of sub-micrometer fluorapatite crystals in niobium-doped fluorapatite glass-ceramics for biomedical applications. Glass-ceramic specimens were prepared by casting and heat treatment between 700 and 1200°C using a fast or a slow heating rate. The microstructure was characterized by atomic force microscopy and scanning electron microscopy. Crystalline phases were analyzed by x-ray diffraction. AFM of the as-cast glass revealed that amorphous phase separation occurred in this system. XRD confirmed the presence of fluorapatite in all specimens, together with forsterite and enstatite at higher temperatures. Both heating rate and heat treatment temperature strongly influenced microstructure and crystallinity. A dual microstructure with sub-micrometer fluorapatite crystals and polygonal forsterite crystals was obtained when slow heating rates and crystallization temperatures between 950 and 1100°C were used. Needle-shaped fluorapatite crystals appeared after heat treatment above 1100°C. Fast heating rates led to an increase in crystal size. Heat treatment temperatures should remain below 1100°C, together with slow heating rates, to prevent crystal dissolution, and preserve a dual microstructure of finely dispersed sub-micrometer crystals without growth of needle-shaped crystals. PMID:22454333

  8. Investigations on optical properties of Sm{sup 3+} ion doped boro-phosphate glasses

    SciTech Connect

    Vijayakumar, R.; Suthanthirakumar, P.; Karthikeyan, P.; Marimuthu, K.

    2015-06-24

    The Sm{sup 3+} doped Boro-phosphate glasses with the chemical composition 60H{sub 3}BO{sub 3}+20Li{sub 2}CO{sub 3}+10ZnO+(10−x) H{sub 6}NO{sub 4}P+xSm{sub 2}O{sub 3} (where x= 0.1, 0.5, 1 and 2 in wt%) have been prepared by melt quenching technique. The prepared glasses were characterized through optical absorption and luminescence spectral measurements. The band gap energies corresponding to the direct and indirect allowed transitions and the Urbach’s energy values were estimated from the absorption spectra. Judd-Ofelt intensity parameters have been derived to predict the radiative properties of the various emission transitions. In order to identify the emission color of the prepared glasses, the emission intensities were analyzed using CIE 1931 color chromaticity diagram. The energy transfer process takes place between Sm{sup 3+}−Sm{sup 3+} ions through cross-relaxation mechanism have also been investigated and the results were discussed and reported.

  9. Development of ytterbium-doped oxyfluoride glasses for laser cooling applications

    PubMed Central

    Krishnaiah, Kummara Venkata; Soares de Lima Filho, Elton; Ledemi, Yannick; Nemova, Galina; Messaddeq, Younes; Kashyap, Raman

    2016-01-01

    Oxyfluoride glasses doped with 2, 5, 8, 12, 16 and 20 mol% of ytterbium (Yb3+) ions have been prepared by the conventional melt-quenching technique. Their optical, thermal and thermo-mechanical properties were characterized. Luminescence intensity at 1020 nm under laser excitation at 920 nm decreases with increasing Yb3+ concentration, suggesting a decrease in the photoluminescence quantum yield (PLQY). The PLQY of the samples was measured with an integrating sphere using an absolute method. The highest PLQY was found to be 0.99(11) for the 2 mol% Yb3+: glass and decreases with increasing Yb3+ concentration. The mean fluorescence wavelength and background absorption of the samples were also evaluated. Upconversion luminescence under 975 nm laser excitation was observed and attributed to the presence of Tm3+ and Er3+ ions which exist as impurity traces with YbF3 starting powder. Decay curves for the Yb3+: 2F5/2 → 2F7/2 transition exhibit single exponential behavior for all the samples, although lifetime decrease was observed for the excited level of Yb3+ with increasing Yb3+ concentration. Also observed are an increase in the PLQY and a slight decrease in lifetime with increasing the pump power. Finally, the potential of these oxyfluoride glasses with high PLQY and low background absorption for laser cooling applications is discussed. PMID:26915817

  10. XRD and IR Studies of Yb{sup 3+} Doped Tellurite Glass

    SciTech Connect

    Sahar, M. R.; Isa, H. Noor

    2011-03-30

    Ytterbium doped sodium-tellurite glasses having composition of (80-x) TeO{sub 2}-20Na{sub 2}O-(x)Yb{sub 2}O{sub 3}(where x = 0.0-2.0 mol%) are prepared by melt quenching technique. The crystallinity of the glass has been examined using X-ray diffraction technique. All glass are found to be amorphous in nature. Meanwhile the transmission spectroscopy is determine by using Infrared Spectroscopy. It is found that the absorption vibrational spectra occurs at range 3405-3423 cm{sup -1}, 1632-1643 cm{sup -1}, 1377-1382 cm{sup -1}, 721-732 cm{sup -1} and 589-606 cm{sup -1} peaks. The predominant peaks around 700 cm{sup -1} is due to the Te-O-Te vibration while peak at 600 cm{sup -1} is due to the vibration of Yb{sup 3+} ions.

  11. Development of ytterbium-doped oxyfluoride glasses for laser cooling applications.

    PubMed

    Krishnaiah, Kummara Venkata; de Lima Filho, Elton Soares; Ledemi, Yannick; Nemova, Galina; Messaddeq, Younes; Kashyap, Raman

    2016-01-01

    Oxyfluoride glasses doped with 2, 5, 8, 12, 16 and 20 mol% of ytterbium (Yb(3+)) ions have been prepared by the conventional melt-quenching technique. Their optical, thermal and thermo-mechanical properties were characterized. Luminescence intensity at 1020 nm under laser excitation at 920 nm decreases with increasing Yb(3+) concentration, suggesting a decrease in the photoluminescence quantum yield (PLQY). The PLQY of the samples was measured with an integrating sphere using an absolute method. The highest PLQY was found to be 0.99(11) for the 2 mol% Yb(3+): glass and decreases with increasing Yb(3+) concentration. The mean fluorescence wavelength and background absorption of the samples were also evaluated. Upconversion luminescence under 975 nm laser excitation was observed and attributed to the presence of Tm(3+) and Er(3+) ions which exist as impurity traces with YbF3 starting powder. Decay curves for the Yb(3+): (2)F5/2 → (2)F7/2 transition exhibit single exponential behavior for all the samples, although lifetime decrease was observed for the excited level of Yb(3+) with increasing Yb(3+) concentration. Also observed are an increase in the PLQY and a slight decrease in lifetime with increasing the pump power. Finally, the potential of these oxyfluoride glasses with high PLQY and low background absorption for laser cooling applications is discussed. PMID:26915817

  12. Effect of different conventional melt quenching technique on purity of lithium niobate (LiNbO3) nano crystal phase formed in lithium borate glass

    NASA Astrophysics Data System (ADS)

    Kashif, Ismail; Soliman, Ashia A.; Sakr, Elham M.; Ratep, Asmaa

    2012-01-01

    The glass system (45Li2O + 45B2O3 + 10Nb2O5) was fabricated by the conventional melt quenching technique poured in water, at air, between two hot plates and droplets at the cooled surface. The glass and glass ceramics were studied by differential thermal analysis (DTA) and X-ray diffraction (XRD). The as quenched samples poured in water and between two hot plates were amorphous. The samples poured at air and on cooled surface were crystalline as established via X-ray powder diffraction (XRD) studies. Differential thermal analysis was measured. The glass transition temperature (Tg) and the crystallization temperatures were calculated. Lithium niobate (LiNbO3) was the main phase in glass ceramic poured at air, droplets at the cooled surface and the heat treated glass sample at 500, 540 and 580 °C in addition to traces from LiNb3O8. Crystallite size of the main phases determined from the X-ray diffraction peaks is in the range of <100 nm. The fraction of crystalline (LiNbO3) phase decreases with increase in the heat treatment temperature.

  13. IRRS, UV-Vis-NIR absorption and photoluminescence upconversion in Ho 3+-doped oxyfluorophosphate glasses

    NASA Astrophysics Data System (ADS)

    Karmakar, Basudeb

    2005-09-01

    Infrared reflection spectroscopic (IRRS), ultraviolet-visible-near infrared (UV-Vis-NIR) absorption and photoluminescence upconversion properties with special emphasis on the spectrochemistry of the oxyfluorophosphate (oxide incorporated fluorophosphates) glasses of the Ba(PO 3) 2-AlF 3-CaF 2-SrF 2-MgF 2-Ho 2O 3 system have been studied with different concentrations (0.1, 0.3 and 1.0 mol%) of Ho 2O 3. IRRS spectral band position and intensity of Ho 3+ ion doped oxyfluorophosphate glasses have been discussed in terms of reduced mass and force constant. UV-Vis-NIR absorption band position has been justified with quantitative calculation of nephelauxetic parameter and covalent bonding characteristics of the host. NIR to visible upconversion has been investigated by exciting at 892 nm at room temperature. Three upconverted bands originated from the 5F 3→ 5I 8, ( 5S 2, 5F 4)→ 5I 8 and 5F 5→ 5I 8 transitions have found to be centered at 491 nm (blue, medium), 543 nm (green, very strong) and 658 nm (red, weak), respectively. These bands have been justified from the evaluation of the absorption, normal (down conversion) fluorescence and excitation spectra. The upconversion processes have been explained by the excited state absorption (ESA), energy transfer (ET) and cross relaxation (CR) mechanisms involving population of the metastable (storage) energy levels by multiphonon deexcitation effect. It is evident from the IRRS study that the upconversion phenomena are expedited by the low multiphonon relaxation rate in oxyfluorophosphate glasses owing to their high intense low phonon energy (˜600 cm -1) which is very close to that of fluoride glasses (500-600 cm -1).

  14. Production and characterization of H3BO3-Li2CO3-K2CO3-MgO glass for dosimetry

    NASA Astrophysics Data System (ADS)

    Marini, Andrea; Valença, João V. B.; Oliveira, Raquel A. P.; Souza, Susana O.; Ciolini, Riccardo; d'Errico, Francesco

    2015-11-01

    Borate glasses are suitable for thermoluminescent dosimetry. In particular, borate glasses doped with different elements show good characteristics in terms of linearity, sensitivity and effective atomic number. However, these glasses are also hygroscopic, which can reduce their viability as dosimeters. In this work, the characteristics of borate glasses made with lithium and potassium oxides (LKB) were studied. To improve the glass features new formulations adding different amounts of magnesium oxide were developed. Mg improves the stability of the glasses since it reduces the mobility of the alkali ions and thus may reduce the hygroscopicity of the LKB glass. Three glass formulations containing 0, 5 and 11 mol% of magnesium oxide were produced by wet quenching method in order to determine the effect of Mg specifically on hygroscopicity and high-temperature resistance. The possibility to use this material for optically stimulated luminescence dosimetry was demonstrated. The LKB glass containing 11 mol% of Mg was found to withstand higher temperatures and to present the lower hygroscopicity compared to the other formulations.

  15. Survey and research on up-conversion emission character and energy transition of Yb3+/Er3+/Tm3+ co-doped phosphate glass and glass ceramic

    NASA Astrophysics Data System (ADS)

    Yu, Yin; Song, Feng; Ming, Chengguo; Liu, Jiadong; Li, Wei; Liu, Yanling; Zhao, Hongyan

    2012-11-01

    By conventional high-temperature melting method, Yb3+/Er3+/Tm3+ co-doped phosphate glass was synthesized. After annealing the precursor glass, the phosphate glass ceramic (GC) was obtained. By measuring the X-ray diffraction (XRD) spectrum, it is proved that the LiYbP4O12 and Li6P6O18 nano-crystals have existed in the phosphate GC. The up-conversion (UC) emission intensity of the GC is obvious stronger compared to that of the glass. The reason is that the shorter distance between rare earth ions in the glass ceramic increases the energy transitions from the sensitized ions (Yb3+) to the luminous ions (Er3+ and Tm3+). By studying the dependence of UC emissions on the pump power, the 523 and 546 nm green emissions of Er3+ ions in the glass are two-photon processes. But in the glass ceramic, they are two/three-photon processes. The phenomenon implies that a three-photon process has participated in the population of the two green emissions. Using Dexter theory, we discuss the energy transitions of Er3+ and Tm3+. The results indicate the energy transition of Tm3+ to Er3+ is very strong in the GC, which changes the population mechanism of UC emissions of Er3+.

  16. Structure and vibrational modes of AgI-doped AsSe glasses: Raman scattering and ab initio calculations

    SciTech Connect

    Kostadinova, O.; Chrissanthopoulos, A.; Petkova, T.; Petkov, P.; Yannopoulos, S.N.

    2011-02-15

    We report an investigation of the structure and vibrational modes of (AgI){sub x} (AsSe){sub 100-x}, bulk glasses using Raman spectroscopy and first principles calculations. The short- and medium-range structural order of the glasses was elucidated by analyzing the reduced Raman spectra, recorded at off-resonance conditions. Three distinct local environments were revealed for the AsSe glass including stoichiometric-like and As-rich network sub-structures, and cage-like molecules (As{sub 4}Se{sub n}, n=3, 4) decoupled from the network. To facilitate the interpretation of the Raman spectra ab initio calculations are employed to study the geometric and vibrational properties of As{sub 4}Se{sub n} molecular units that are parts of the glass structure. The incorporation of AgI causes appreciable structural changes into the glass structure. AgI is responsible for the population reduction of molecular units and for the degradation of the As-rich network-like sub-structure via the introduction of As-I terminal bonds. Ab initio calculations of mixed chalcohalide pyramids AsSe{sub m}I{sub 3-m} provided useful information augmenting the interpretation of the Raman spectra. -- Graphical abstract: Raman scattering and ab initio calculations are employed to study the structure of AgI-AsSe superionic glasses. The role of mixed chalcohalide pyramidal units as illustrated in the figure is elucidated. Display Omitted Research highlights: {yields} Doping binary As-Se glasses with AgI cause dramatic changes in glass structure. {yields} Raman scattering and ab initio calculations determine changes in short- and medium-range order. {yields} Three local environments exist in AsSe glass including a network sub-structure and cage-like molecules. {yields} Mixed chalcohalide pyramids AsSe{sub m}I{sub 3-m} dominate the AgI-doped glass structure.

  17. Corrosion of soda lime silicate glasses co-doped with Gd2O3 and Y2O3

    NASA Astrophysics Data System (ADS)

    Wang, Mitang; Li, Mei; Cheng, Jinshu; He, Feng; Liu, Zhaogang; Hu, Yanhong

    2014-01-01

    Corrosion behaviors of Gd2O3 and Y2O3 co-doped silicate glasses have been carried out at low reaction progress. The better enhance effect of co-doping with Gd2O3 and Y2O3 on the silicate glass resistance against attacking of neutral and acid media is observed, while the alkaline resistance is Y2O3 > Gd2O3 + Y2O3 > Gd2O3. Moreover, extreme value is also observed in variation of released ions concentration, pH value and mass loss of glass when substituting Y2O3 for Gd2O3.

  18. Effects of F- on the optical and spectroscopic properties of Yb3+/Al3+-co-doped silica glass

    NASA Astrophysics Data System (ADS)

    Xu, Wenbin; Yu, Chunlei; Wang, Shikai; Lou, Fengguang; Feng, Suya; Wang, Meng; Zhou, Qinling; Chen, Danping; Hu, Lili; Guzik, Malgorzata; Boulon, Georges

    2015-04-01

    Yb3+/Al3+-co-doped silica glasses with different F- content were prepared in this work by sol-gel method combined with high temperature sintering. XRF, FTIR and XPS methods were used to confirm the presence of F-. The effects of F- on the optical and spectroscopic properties of these glasses have been investigated. It is worth to notice that the F-/Si4+ mass ratio equal to 9% is a significant value showing a real change in the variation trends of numerous following parameters: refractive index, UV absorption edge, absorption and emission cross sections, scalar crystal-field NJ and fluorescent lifetimes. Furthermore, introduction of F- can adjust the refractive index of Yb3+/Al3+-co-doped silica glass and it is useful for large mode area (LMA) fibers.

  19. Local-field approximation of homonuclear dipolar interactions in ⁷Li-NMR: density-matrix calculations and random-walk simulations tested by echo experiments on borate glasses.

    PubMed

    Storek, Michael; Jeffrey, Kenneth R; Böhmer, Roland

    2014-01-01

    NMR echo techniques have proven to be important to study dynamics in ion conductors and other solid materials. Using the spin-3/2 nucleus (7)Li as a probe, both the quadrupolar and the often neglected homonuclear dipolar interactions modulate the NMR frequency as the ion performs jump processes. Retaining only the local-field term of the many-body Hamiltonian, the impact of the dipolar interaction on various echo experiments was studied using spin dynamics calculations yielding products of dipolar and quadrupolar correlation functions. Using a simple stochastic model these functions were simulated with particular emphasis on the impact of ionic motions and on the conditions under which the dipolar and quadrupolar contributions factorize. The results of the computations and of the random-walk simulations are compared with experimental data obtained for various lithium borate and lithium borophosphate glasses. It is concluded that the local-field approximation is a useful means of treating the Li-Li dipole interactions and that the simple model that we introduce is capable of describing many experimentally observed features. Furthermore, because the dipolar and quadrupolar contributions essentially factorize, a selective determination of the corresponding correlation functions becomes possible. PMID:24593983

  20. Superresolution Structure Optical Disk with Semiconductor-Doped Glass Mask Layer Containing CdSe Nanoparticles

    NASA Astrophysics Data System (ADS)

    Yeh, Tung‑Ti; Wang, Jr‑Hau; Hsieh, Tsung‑Eong; Shieh, Han‑Ping D.

    2006-02-01

    In this work, we demonstrate a distinct superresolution phenomenon and signal properties of an optical disk with a semiconductor-doped glass (SDG) mask layer containing CdSe nanoparticles. It was found that the 69 nm marks could be consistently retrieved at reading power (Pr) = 4 mW with carrier-to-noise ratio (CNR) = 13.56 dB. The signals were clearly resolved with CNRs nearly equal to 40 dB at Pr=4 mW when the recorded marks were larger than 100 nm. The cyclability test indicated that the CdSe-SiO2 SDG layer might serve as a stable and reliable optical mask layer in 105 readout cycles.

  1. Optical properties of phosphate glasses co-doped with Yb3+ and silver nanoparticles

    NASA Astrophysics Data System (ADS)

    A. Vallejo H., M.; A. Martinez G., M.; V. Kiryanov, A.; L. Lucio M., J.

    2014-12-01

    We report the fabrication and spectroscopic characterization of Yb3+-doped phosphate glass, also containing silver nitrate. Scanning electron microscopy (SEM) provides the evidence of the formation of silver nano-particles (SNPs), which are formed as a consequence of melting and thermal decomposition of AgNO3. Absorption spectra of the samples in the visible-to-near-infrared spectral range reveal the presence of bands centered at 410 nm associated with the SNP-plasmon resonance, and at 976 nm due to the Yb3+. Under 916-nm laser-diode pumping, the effect of the SNP reflects that: i) the fluorescence in the 950-nm-1150-nm spectral range is strongly enhanced(~ 30 times), while the fluorescence decay time associated with the 2F5/2 → 2F7/2 transition of Yb3+ increases 25%, and ii) the basic lasing properties (saturation pumping intensity, the emission and absorption cross sections) are substantially improved.

  2. Study of spatial rings in TPPOH4 doped in boric acid glass

    NASA Astrophysics Data System (ADS)

    Rao Allam, Srinivasa; Dar, Mudasir H.; Venkatramaiah, N.; Venkatesan, R.; Sharan, Alok

    2015-02-01

    Single beam optical nonlinearity is studied in TPPOH4 doped in boric acid sandwiched films between two microscope glass slides at three different molar concentrations (4×10-4M, 1×10-4M, 5×10-5M). It shows absorption peak at 700nm with bandwidth of 70nm. We have used diode laser output at 671nm to probe resonant optical nonlinearities. We have observed interesting phenomena of formation of spatial concentric rings centered on the z-axis of the sample. To our knowledge this is first such observation of spatial rings in these systems. We have carried out studies to separate the contribution to the ring formation due to absorptive/refractive optical nonlinearity and the thermal nonlinearity.

  3. Degenerate four-wave mixing in semiconductor-doped glasses below the absorption edge

    NASA Astrophysics Data System (ADS)

    Bindra, K. S.; Oak, S. M.; Rustagi, K. C.

    1999-01-01

    We report measurements of degenerate four-wave-mixing reflectivity at a frequency below the band gap of semiconductor-doped glasses in the intensity range 0.5-10 GW/cm2. Up to intensities ~2.5 GW/cm2, the conjugate reflectivity varies like the fourth power of intensity signifying a fifth-order nonlinearity due to band filling by two-photon absorption. Surprisingly, at a higher intensity range the conjugate signal showed a cubic dependence on the pump intensity, which is typical of the χ(3) process. We show that this cubic dependence does not necessarily indicate a third-order process as usually assumed. Instead, it is shown to arise due to a reduction of the effective intensity by nonlinear absorption of the interacting beams.

  4. Investigations on luminescence behavior of Er3+/Yb3+ co-doped boro-tellurite glasses

    NASA Astrophysics Data System (ADS)

    Maheshvaran, K.; Arunkumar, S.; Venkata Krishnaiah, K.; Marimuthu, K.

    2015-01-01

    Er3+/Yb3+ co-doped boro-tellurite glasses with the chemical composition 30TeO2+(24 - x)B2O3 + 15SrO + 10BaO + 10Li2O + 10LiF + 1Er2O3 + xYb2O3 (where x = 0, 0.1, 0.5, 1 and 2 in wt%) have been prepared and their luminescence behavior were studied and reported. Absorption spectral measurements have been used to derive the Judd-Ofelt (JO) intensity parameters from the experimental and calculated oscillator strength values following the JO theory. The various lasing parameters such as stimulated emission cross-section (σEp), experimental and calculated branching ratios (βR) and radiative lifetime (τcal) for the 2H9/2 → 4I15/2, 4S3/2 → 4I15/2 and 4I13/2 → 4I15/2 emission transitions were determined using the JO intensity parameters. The absorption and emission cross-section values for the 4I13/2 → 4I15/2 emission band have been calculated using McCumbar theory and the Gain cross-section for the 4I13/2 → 4I15/2 emission transition also obtained. The upconversion emission mechanism have been studied through various energy transfer processes and the intensity of the upconversion emission transitions are found to increase with the increase in Yb3+ ion concentration. The luminescence decay curves corresponding to the 4I13/2 → 4I15/2 transition of the Er3+/Yb3+ co-doped boro-tellurite glasses under 980 nm excitation wavelength have also been studied and reported in the present work.

  5. Mineral oil soluble borate compositions

    SciTech Connect

    Dulat, J.

    1981-09-15

    Alkali metal borates are reacted with fatty acids or oils in the presence of a low hlb value surfactant to give a stable mineral oil-soluble product. Mineral oil containing the borate can be used as a cutting fluid.

  6. P2O5-doping in waste glasses: evolution of viscosity and crystallization processes

    NASA Astrophysics Data System (ADS)

    Tarrago, Mariona; Espuñes, Alex; Garcia-Valles, Maite; Martinez, Salvador

    2015-04-01

    Current concern for environmental preservation is the main motive for the study of new, more sustainable materials. Increasing amounts of sewage sludge are produced in wastewater treatment plants over the world every day. This fact represents a major problem for the municipalities and industries due to the volume of waste and also to the contaminant elements it may bear, which require expensive conditions for disposal in landfills. Vitrification is an established technique in the inertization of different types of toxic wastes (such as nuclear wastes and contaminated soils) that has been used successfully for sewage sludge. Glasses of basaltic composition (43.48SiO2-14.00Al2O3-12.86Fe2O3-10.00CaO-9.94MgO-3.27Na2O-1.96K2O-0.17MnO-0.55P2O5-2.48TiO2) are used as a laboratory analogous of wastes such as sewage sludge and galvanic sludge to study the properties of the inertization matrix. This basaltic matrix is doped by adding 1%, 2%, 3%, 4% and 20% of P5O5 in order to cover the compositional range of phosphate in sewage sludge encountered in the literature. In this study, the focus has been placed in the effect of the concentration of phosphate (P2O5) in glass stability, thermal properties and evolution of viscosity with temperature. The dependence of viscosity on temperature and the thermal behaviour of these glasses are critical parameters in the design of their production process. Regarding the compositional limits of the mixture, it has been observed that melt reactivity is much increased when P2O5 content is over 4%, hindering the glass conformation process. Moreover, stanfieldite (calcium and magnesium phosphate) crystallized during glass making when phosphate concentration approached 20%, hence establishing the upper limit for glass stability. Viscosity is also dramatically increased in this range, hence requiring production amends. Differential thermal analysis has provided nucleation and crystallization temperatures of the glasses around 915°C and 1050

  7. Comparison of selected optical properties of oxyfluoride glass fibers doped with Er3+ and co-doped with Er3+ Yb3+

    NASA Astrophysics Data System (ADS)

    Augustyn, E.; Stremplewski, P.; Rozanski, M.; Koepke, C.; Dominiak-Dzik, G.; Kępińska, M.; Żelechower, M.

    2011-12-01

    The method of manufacturing and spectroscopic evaluation of the Er3+ ions doped and Er3+-Yb3+co-doped SiO2-Al2O3-Na2CO3-CaO-PbO-PbF2 oxyfluoride glass fibers is presented in the paper. Both optically active elements erbium and ytterbium were introduced into the batch in the form of fluorides. The X-ray diffraction (XRD) technique was applied at each stage of fibers manufacturing in order to control an amorphous structure of the preforms and fibers. Optical studies of glass preforms and fibers (reflection/transmission, absorption, emission, and excited state absorption (ESA)) were directed to examine their suitability as fiber amplifiers at 1.55 μm band.

  8. Impact of Gd3+ doping and glassing solvent deuteration on 13C DNP at 5 Tesla

    NASA Astrophysics Data System (ADS)

    Kiswandhi, Andhika; Lama, Bimala; Niedbalski, Peter; Goderya, Mudrekh; Long, Joanna; Lumata, Lloyd

    Dynamic nuclear polarization (DNP) is a technique which can be used to amplify signals in nuclear magnetic resonance (NMR) and magnetic resonance imaging (MRI) by several thousand-fold. The most commonly available DNP system typically operates at the W-band field or 3.35 T, at which it has been shown that 13C NMR signal can be enhanced by deuteration and Gd3+ doping. In this work, we have investigated the applicability of these procedures at 5 T. Our results indicate that the deuteration of the glassing matrix still yields an enhancement of 13C DNP when 4-oxo-TEMPO free radical is used. The effect is attributed to the lower heat load of the deuterons compared to protons. An addition of a trace amount of Gd3+ gives a modest enhancement of the signal when trityl OX063 is used, albeit with a less pronounced relative enhancement compared to the results obtained at 3.35 T. The results suggest that the enhancement obtained via Gd3+ doping may become saturated at higher field. These results will be discussed using a thermodynamic model of DNP. This work is supported by US Dept of Defense Award No. W81XWH-14-1-0048 and Robert A. Welch Foundation Grant No. AT-1877.

  9. The structure of Er3+-doped oxy-fluoride transparent glass-ceramics studied by Raman scattering

    NASA Astrophysics Data System (ADS)

    Tikhomirov, V. K.; Seddon, A. B.; Ferrari, M.; Montagna, M.; Santos, L. F.; Almeida, R. M.

    2003-11-01

    We show that the structure of transparent oxy-fluoride glass-ceramics formed by heat treatment of glasses of typical composition 32(SiO2):9(AlO1.5):31.5(CdF2):18.5(PbF2): 5.5(ZnF2):3.5(ErF3) mol% consists of ~ 12 nm diameter, Er3+-doped, β-PbF2 nano-crystals embedded in a silica-based glass network and connected to it via non-bridging O and F anions, or fluorine linkages such as Pb-F-Cd and Pb-F-Zn. It is proposed that the glass network structure is mostly chain-like and dominated by Si(O,F)4 tetrahedra with two bridging O and two non-bridging O and/or F atoms (Q2 units). SiO4 tetrahedra with zero and one bridging O (Q0 and Q1 units, respectively) are also present in the glass structure, in the approximate proportion Q0:Q1:Q2 = 1:1:3, a characteristic which appears to be of primary importance. The flexible, chain-like glass-network, with many broken bonds, results in easy accommodation of the Er3+-doped PbF2 nano-crystals, which are grown by heat-treatment of the precursor glass. The boson peak in the Raman spectrum of the precursor glass decreases in intensity upon ceramming and is partly converted to narrow crystalline peaks at lower frequency, consistent with the precipitation of PbF2 crystalline nano-particles. It is suggested that the boson peak involves localized vibrations of broken or stretched Pb-F bonds. The mean free path for these vibrations increases with ceramming, which involves partial crystallization of the glass network, resulting in a shift of the boson peak vibrations to lower-frequency crystalline peaks.

  10. Structural, thermal, optical properties and simulation of white light of titanium-tungstate-tellurite glasses doped with dysprosium

    SciTech Connect

    Jyothi, L.; Upender, G.; Kuladeep, R.; Rao, D. Narayana

    2014-02-01

    Graphical abstract: CIE coordinate diagram of different concentrations of the Dy{sup 3+}-doped TTWD glasses with coordinates in the white light region. - Highlights: • Radiative lifetime of {sup 4}F{sub 9/2} level of Dy{sup 3+} ions is longer in the tellurite glass. • Quantum efficiency is found to be high. • These glasses are suitable materials for generating white light. - Abstract: Structural, thermal, optical properties and simulation of white light of Dy{sup 3+}-doped tellurite glasses of composition TTWD: (75 − x)TeO{sub 2} − 10TiO{sub 2} − 15WO{sub 3} − xDy{sub 2}O{sub 3} (x = 0, 0.1, 0.5, 1.0 and 2.0 mol%) were investigated. Raman spectra revealed that the glass contains TeO{sub 4}, TeO{sub 3}, WO{sub 4} and WO{sub 6} units. Differential scanning calorimetry (DSC) measurements were carried out to measure the glass transition temperature of all the glasses. From the optical absorption spectra, luminescence spectra and using the Judd–Ofelt (JO) analysis, we estimated the radiative transition probabilities, emission cross-sections, branching ratios and radiative lifetimes. The decay curves at lower concentrations are exponential while they show a non-exponential behavior at higher concentrations (≥0.5 mol%) due to energy transfer processes. The effective lifetime for the {sup 4}F{sub 9/2} level decreases with increase in Dy{sub 2}O{sub 3} concentration for the glasses under investigation. The non-exponential decay curves could fit well to the Inokuti–Hirayama (IH) model with S = 6, indicating that the nature of interaction responsible for energy transfer is of dipole–dipole type. Simulation of white light is examined with varying concentration and the results indicate that these glasses are suitable for white light emitting diode applications.

  11. White light emitting Ho{sup 3+}-doped CdS nanocrystal ingrained glass nanocomposites

    SciTech Connect

    Dey, Chirantan; Karmakar, Basudeb; Goswami, Madhumita

    2015-02-23

    We report the generation of white light from Ho{sup 3+} ion doped CdS nanocrystal ingrained borosilicate glass nanocomposites prepared by the conventional melt-quench method. Near visible 405 nm diode laser excited white light emission is produced by tuning the blue emission from the Ho{sup 3+} ions, green band edge, and orange-red surface-state emissions of the nanocrystalline CdS, which are further controlled by the size of the nanocrystals. The absorption and emission spectra evidenced the excitation of Ho{sup 3+} ions by absorption of photons emitted by the CdS nanocrystals. The high color rendering index (CRI = 84–89) and befitting chromaticity coordinates (x = 0.308–0.309, y = 0.326–0.338) of white light emission, near visible harmless excitation wavelength (405 nm), and high absorbance values at excitation wavelength point out that these glass nanocomposites may serve as a prominent candidate for resin free high power white light emitting diodes.

  12. Charge carrier transport in molecularly doped polycarbonate as a test case for the dipolar glass model.

    PubMed

    Novikov, S V; Tyutnev, A P

    2013-03-14

    We present the results of Monte Carlo simulations of the charge carrier transport in a disordered molecular system containing spatial and energetic disorders using the dipolar glass model. Model parameters of the material were chosen to fit a typical polar organic photoconductor polycarbonate doped with 30% of aromatic hydrazone, whose transport properties are well documented in literature. Simulated carrier mobility demonstrates a usual Poole-Frenkel field dependence and its slope is very close to the experimental value without using any adjustable parameter. At room temperature transients are universal with respect to the electric field and transport layer thickness. At the same time, carrier mobility does not depend on the layer thickness and transients develop a well-defined plateau where the current does not depend on time, thus demonstrating a non-dispersive transport regime. Tails of the transients decay as power law with the exponent close to -2. This particular feature indicates that transients are close to the boundary between dispersive and non-dispersive transport regimes. Shapes of the simulated transients are in very good agreement with the experimental ones. In summary, we provide a first verification of a self-consistency of the dipolar glass transport model, where major transport parameters, extracted from the experimental transport data, are then used in the transport simulation, and the resulting mobility field dependence and transients are in very good agreement with the initial experimental data.

  13. Charge carrier transport in molecularly doped polycarbonate as a test case for the dipolar glass model

    NASA Astrophysics Data System (ADS)

    Novikov, S. V.; Tyutnev, A. P.

    2013-03-01

    We present the results of Monte Carlo simulations of the charge carrier transport in a disordered molecular system containing spatial and energetic disorders using the dipolar glass model. Model parameters of the material were chosen to fit a typical polar organic photoconductor polycarbonate doped with 30% of aromatic hydrazone, whose transport properties are well documented in literature. Simulated carrier mobility demonstrates a usual Poole-Frenkel field dependence and its slope is very close to the experimental value without using any adjustable parameter. At room temperature transients are universal with respect to the electric field and transport layer thickness. At the same time, carrier mobility does not depend on the layer thickness and transients develop a well-defined plateau where the current does not depend on time, thus demonstrating a non-dispersive transport regime. Tails of the transients decay as power law with the exponent close to -2. This particular feature indicates that transients are close to the boundary between dispersive and non-dispersive transport regimes. Shapes of the simulated transients are in very good agreement with the experimental ones. In summary, we provide a first verification of a self-consistency of the dipolar glass transport model, where major transport parameters, extracted from the experimental transport data, are then used in the transport simulation, and the resulting mobility field dependence and transients are in very good agreement with the initial experimental data.

  14. Glass beads and Ge-doped optical fibres as thermoluminescence dosimeters for small field photon dosimetry

    NASA Astrophysics Data System (ADS)

    Jafari, S. M.; Alalawi, A. I.; Hussein, M.; Alsaleh, W.; Najem, M. A.; Hugtenburg, R. P.; Bradley, D. A.; Spyrou, N. M.; Clark, C. H.; Nisbet, A.

    2014-11-01

    An investigation has been made of glass beads and optical fibres as novel dosimeters for small-field photon radiation therapy dosimetry. Commercially available glass beads of largest dimension 1.5 mm and GeO2-doped SiO2 optical fibres of 5 mm length and 120 µm diameter were characterized as thermoluminescence dosimeters. Results were compared against Monte-Carlo simulations with BEAMnrc/DOSXYZnrc, EBT3 Gafchromic film, and a high-resolution 2D-array of liquid-filled ionization chambers. Measurements included relative output factors and dose profiles for square-field sizes of 1, 2, 3, 4, and 10 cm. A customized Solid-Water® phantom was employed, and the beads and fibres were placed at defined positions along the longitudinal axis to allow accurate beam profile measurement. Output factors and the beam profile parameters were compared against those calculated by BEAMnrc/DOSXYZnrc. The output factors and field width measurements were found to be in agreement with reference measurements to within better than 3.5% for all field sizes down to 2 cm2 for both dosimetric systems, with the beads showing a discrepancy of no more than 2.8% for all field sizes. The results confirm the potential of the beads and fibres as thermoluminescent dosimeters for use in small photon radiation field sizes.

  15. Highly (0001)-oriented Al-doped ZnO polycrystalline films on amorphous glass substrates

    NASA Astrophysics Data System (ADS)

    Nomoto, Junichi; Inaba, Katsuhiko; Osada, Minoru; Kobayashi, Shintaro; Makino, Hisao; Yamamoto, Tetsuya

    2016-09-01

    Very thin aluminum-doped zinc oxide (AZO) films with a well-defined (0001) orientation and a surface roughness of 0.357 nm were deposited on amorphous glass substrates at a temperature of 200 °C by radio frequency magnetron sputtering, which are promising, particularly in terms of orientation evolution, surface roughness, and carrier transport, as buffer layers for the subsequent deposition of highly (0001)-oriented AZO polycrystalline films of 490 nm thickness by direct current (DC) magnetron sputtering. Sintered AZO targets with an Al2O3 content of 2.0 wt. % were used. DC magnetron sputtered AZO films on bare glass substrates showed a mixed (0001) and the others crystallographic orientation, and exhibited a high contribution of grain boundary scattering to carrier transport, resulting in reduced Hall mobility. Optimizing the thickness of the AZO buffer layers to 10 nm led to highly (0001)-oriented bulk AZO films with a marked reduction in the above contribution, resulting in AZO films with improved Hall mobility together with enhanced carrier concentration. The surface morphology and point defect density were also improved by applying the buffer layers, as shown by atomic force microscopy and Raman spectroscopy, respectively.

  16. Glass beads and Ge-doped optical fibres as thermoluminescence dosimeters for small field photon dosimetry.

    PubMed

    Jafari, S M; Alalawi, A I; Hussein, M; Alsaleh, W; Najem, M A; Hugtenburg, R P; Bradley, D A; Spyrou, N M; Clark, C H; Nisbet, A

    2014-11-21

    An investigation has been made of glass beads and optical fibres as novel dosimeters for small-field photon radiation therapy dosimetry. Commercially available glass beads of largest dimension 1.5 mm and GeO2-doped SiO2 optical fibres of 5 mm length and 120 µm diameter were characterized as thermoluminescence dosimeters. Results were compared against Monte-Carlo simulations with BEAMnrc/DOSXYZnrc, EBT3 Gafchromic film, and a high-resolution 2D-array of liquid-filled ionization chambers. Measurements included relative output factors and dose profiles for square-field sizes of 1, 2, 3, 4, and 10 cm. A customized Solid-Water® phantom was employed, and the beads and fibres were placed at defined positions along the longitudinal axis to allow accurate beam profile measurement. Output factors and the beam profile parameters were compared against those calculated by BEAMnrc/DOSXYZnrc. The output factors and field width measurements were found to be in agreement with reference measurements to within better than 3.5% for all field sizes down to 2 cm2 for both dosimetric systems, with the beads showing a discrepancy of no more than 2.8% for all field sizes. The results confirm the potential of the beads and fibres as thermoluminescent dosimeters for use in small photon radiation field sizes.

  17. Detection and qualification of optimum antibacterial and cytotoxic activities of silver-doped bioactive glasses.

    PubMed

    Gholipourmalekabadi, Mazaher; Nezafati, Nader; Hajibaki, Leila; Mozafari, Masoud; Moztarzadeh, F; Hesaraki, Saeed; Samadikuchaksaraei, Ali

    2015-08-01

    This study aims to detect the optimum antibacterial activity of silver-doped bioactive glasses (Ag-BGs) for prevention of post-transplant infections in tissue engineering. The results have shown that the Ag-BG samples had broad-spectrum antibacterial efficacy in an Ag concentration-dependent manner. The 2% Ag-BG had the highest effect during the first 10 min to 72 h. The minimum inhibitory concentration of 2% Ag-BG was estimated to be 2 mg/ml for Escherichia coli (E. coli) and Pseudomonas aeruginosa (P. aeruginosa) and 2.66 mg/ml for Staphylococcus aureus (S. aureus). A concentration of 0.5% Ag-BG repressed growth of E. coli after 1 h, but did not have any detectable antibacterial effect for longer periods. Evaluation of the effects of prepared Ag-BG on human osteoblast cells viability showed that 1 and 2% samples changed the cell proliferation rate in masses of more than 3.33 and 2 mg/ml, respectively. Moreover, in a typical manner, the release of Ag ions from the glass structure started immediately, continued steadily and affected bacterial growth when it reached its critical concentration in the medium. This systematic study can illustrate the optimum antibacterial property of the Ag-BG samples in masses of 3.33 and 2 mg/ml for 1 and 2% Ag, respectively, for prevention of post-transplant infections. PMID:26224350

  18. Microstructure and optical properties of CdI{sub 2} doped silver vanadate glass-nanocomposites

    SciTech Connect

    Kabi, S.; Ghosh, A.

    2012-11-15

    Graphical abstract: TEM micrograph for 0.20CdI{sub 2}–0.80(0.60Ag{sub 2}O–0.40V{sub 2}O{sub 5}) and SAED pattern (shown right inset) from the selected area. High resolution image for a particle along with its FFT pattern is also shown in left inset. Highlights: ► CdI{sub 2} doped silver vanadate glass nanocomposites have been prepared. ► Microstructure of the compositions has been investigated. ► Nanocrystalline phases (β-AgI, Cd{sub 2}V{sub 2}O{sub 7}, etc.) are distributed in the glass matrix. ► Volume fraction of these crystalline phases increases with increase of CdI{sub 2} content. ► Formation of Cd{sub 2}V{sub 2}O{sub 7} and β-AgI phase confirms the Cd–Ag exchange in the samples. -- Abstract: Microstructure and optical properties of glass-nanocomposites of compositions xCdI{sub 2}–(1 − x)(0.60Ag{sub 2}O–0.40V{sub 2}O{sub 5})(x = 0.0–0.20) have been reported in this paper. X-ray diffraction patterns show the amorphous nature for the compositions x = 0 and 0.05. However, nanocrystalline phases have been observed in these compositions in electron microscopic studies. X-ray diffraction and electron microscopic studies reveal formation of different nanocrystalline phases such as β-AgI, Cd{sub 2}V{sub 2}O{sub 7}, Ag{sub 4}V{sub 2}O{sub 7} distributed within the amorphous matrix for the compositions x = 0.05–0.20. The presence of Cd{sub 2}V{sub 2}O{sub 7} and β-AgI phase for x = 0.05–0.20 confirms the exchange of coordination between Cd and Ag in these samples. The crystalline volume fraction increases with the increase of CdI{sub 2} content in these compositions. The average size of the nanocrystalline phases was estimated from the transmission and scanning electron microscopic studies. The network structure of the glass nanocomposites has been studied using Fourier transform infrared spectroscopy. Differential scanning calorimetric results show that the embedded nanocrystals decrease the glass transition temperature.

  19. Formation, structural and optical characterization of neodymium doped-zinc soda lime silica based glass

    NASA Astrophysics Data System (ADS)

    Zamratul, M. I. M.; Zaidan, A. W.; Khamirul, A. M.; Nurzilla, M.; Halim, S. A.

    New glass system of neodymium - doped zinc soda lime silica glass has been synthesized for the first time by melt-quenching of glass waste soda lime silica (SLS) with zinc oxide (ZnO) as precursor glass and Nd2O3 as dopant. In order to examine the effect of Nd3+ on the structural and optical properties, the prepared sample of structure [(ZnO)0.5(SLS)0.5](Nd2O3)x (x = 0, 1, 2, 3, 4 and 5 wt%) was characterized through X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, UV-Vis spectroscopy (UV-Vis) and the photoluminescence (PL). XRD pattern justifies the amorphous nature of synthesized glasses. FTIR spectroscopy has been used to observe the structural evolution of ZnO4 and SiO4 groups. The UV-Vis-NIR absorption spectra reveals seven peaks centered at excitation of electron from ground state 4I9/2 to 4D3/2 + 4D5/2 (∼360 nm), 2G9/2 + 2D3/2 + 2P3/2(∼470 nm), 2K13/2 + 4G7/2 + 4G9/2 (∼523 nm), 4G5/2 + 2G7/2 (∼583 nm), 4F9/2 (∼678 nm), 4S3/2 + 4F7/2 (∼748 nm) and 4F5/2 + 2H9/2 (∼801 nm). PL spectra under the excitation of 800 nm display four emission bands centered at 531 nm, 598 nm, 637 nm and 671 nm corresponding to 4G7/2 → 4I9/2, (4G7/2 → 4I11/2, 4G5/2 → 4I9/2), (4G5/2 → 4I11/2) and (4G7/2 → 4I13/2, 4G5/2 → 4I11/2) respectively.

  20. Spectroscopic and glass transition investigations on Nd{sup 3+}-doped NaF-Na{sub 2}O-B{sub 2}O{sub 3} glasses

    SciTech Connect

    Karthikeyan, B.; Mohan, S

    2004-08-03

    New developments in photonic technology need new materials for various applications. In the present report, Nd{sup 3+}-doped NaF-Na{sub 2}O-B{sub 2}O{sub 3} glasses were prepared and the spectroscopic and glass transition properties were analysed. The Fourier transform infrared spectral studies reveal that the glass contains BO{sub 3} and BO{sub 4} units as the local structures and the Na{sup +} ions as the network modifiers. The absorption studies were carried out by using Judd-Ofelt theory, the experimental and theoretical oscillator strengths were also calculated. The emission spectral study was done for the 1 mol% Nd-doped glass and the spontaneous emission probability and stimulated emission cross-sections for the {sup 4}F{sub 3/2}{yields}{sup 4}I{sub 9/2}, {sup 4}I{sub 11/2} transitions were calculated using the J-O parameters.

  1. Luminescence properties of Tb3+-doped zinc phosphate glasses for green laser application

    NASA Astrophysics Data System (ADS)

    Juárez-Batalla, J.; Meza-Rocha, A. N.; Muñoz H., G.; Camarillo, I.; Caldiño, U.

    2016-08-01

    Tb3+-doped zinc phosphate glasses of composition in mol%: (100.0 - x)Zn(PO3)2 - xTb2O3, x = 0.6, 1.0, 2.0 and 5.0, were prepared by conventional melt quenching technique and characterized by photoluminescence and decay time spectroscopy. The integrated intensities of the 5D4 → 7F5 (green at 541 nm) and 5D3 → 7F4 (blue at 435 nm) emissions and their intensity ratios IG/IB upon 350 nm excitation have been evaluated as function of Tb3+ concentration. The CIE1931 color of the glasses excited at 350 nm varies from turquoise to green by increasing the Tb3+ content. The increased IG/IB ratio up to a factor of 364 for the phosphor with the highest Tb3+ content (ZP5Tb) is consistent with the observed shift toward the green region in the CIE coordinates, so that the ZP5Tb glass exhibits a green color purity of 66.9% with chromaticity coordinates (0.290, 0.581), being very close to those (0.29, 0.60) of European Broadcasting Union illuminant green. This interesting feature of the ZP5Tb phosphor, together with an experimental branching ratio larger than 60% of the 5D4 → 7F5 green emission, highlights its capability as solid state green laser pumped by AlGaN (350 nm) LEDs. The decay time profiles of the 5D3 level resulted to be non-exponential for all the studied concentrations due to energy transfer between Tb3+ ions through cross-relaxation. Such decay profiles were well fitted to the Inokuti-Hirayama model for S = 6, which indicates that an electric dipole-dipole interaction might be the dominant mechanism in the cross-relaxation energy transfer occurring in Tb3+ ion clusters.

  2. Structural and luminescence behaviour of Er3+ doped telluro-fluoroborate glasses

    NASA Astrophysics Data System (ADS)

    Karthikeyan, P.; Suthanthirakumar, P.; Vijayakumar, R.; Marimuthu, K.

    2015-03-01

    The Er3+ doped telluro-fluoroborate glasses with the chemical composition (30 - x)B2O3 + 30TeO2 + 16ZnO + 10ZnF2 + 7CaF2 + 7BaF2 + xEr2O3 (x = 0.05, 0.1, 0.5, 0.75, 1.0 and 3 in wt%) have been prepared by melt quenching technique and characterized through XRD, SEM, FTIR, Raman, absorption and luminescence spectral analysis. The XRD and SEM measurements were made to examine the amorphous nature. The presence of various stretching and bending vibration modes of functional groups have been investigated through FTIR and Raman spectra. The bonding parameters (β bar and δ) were calculated from the absorption spectra to claim the covalent/ionic nature of the metal-ligand bond in the prepared glasses. From the absorption spectra, optical band gap energies (Eopt) corresponding to the direct and indirect allowed transitions were calculated to analyze the electronic band structure. The Urbach energy values have also been estimated and discussed. The Judd-Ofelt (JO) intensity parameters (Ωλ (λ = 2, 4, 6)) were determined from the absorption spectra in order to study the symmetry around the RE ion site and used to compute the radiative properties such as transition probability (AR), stimulated emission cross-section ( σPE) and branching ratios (βR) for the different emission transitions. The emission intensities of the prepared glasses were characterized through CIE 1931 chromaticity diagram and the results were discussed and compared with the reported literature.

  3. Energy transfer and energy level decay processes in Tm{sup 3+}-doped tellurite glass

    SciTech Connect

    Gomes, Laercio; Lousteau, Joris; Milanese, Daniel; Scarpignato, Gerardo C.; Jackson, Stuart D.

    2012-03-15

    The primary excited state decay and energy transfer processes in singly Tm{sup 3+}-doped TeO{sub 2}:ZnO:Bi{sub 2}O{sub 3}:GeO{sub 2} (TZBG) glass relating to the {sup 3}F{sub 4}{yields}{sup 3}H{sub 6}{approx}1.85 {mu}m laser transition have been investigated in detail using time-resolved fluorescence spectroscopy. Selective laser excitation of the {sup 3}H{sub 4} manifold at 794 nm, the {sup 3}H{sub 5} manifold at 1220 nm, and {sup 3}F{sub 4} manifold at 1760 nm has established that the {sup 3}H{sub 5} manifold is entirely quenched by multiphonon relaxation in tellurite glass. The luminescence from the {sup 3}H{sub 4} manifold with an emission peak at 1465 nm suffers strong suppression due to cross relaxation that populates the {sup 3}F{sub 4} level with a near quadratic dependence on the Tm{sup 3+} concentration. The {sup 3}F{sub 4} lifetime becomes longer as the Tm{sup 3+} concentration increases due to energy migration and decreases to 2.92 ms when [Tm{sup 3+}] = 4 mol. % as a result of quasi-resonant energy transfer to free OH{sup -} radicals present in the glass at concentrations between 1 x 10{sup 18} cm{sup -3} and 2 x 10{sup 18} cm{sup -3}. Judd-Ofelt theory in conjunction with absorption measurements were used to obtain the radiative lifetimes and branching ratios of the energy levels located below 25 000 cm{sup -1}. The spectroscopic parameters, the cross relaxation and Tm{sup 3+}({sup 3}F{sub 4}) {yields} OH{sup -} energy transfer rates were used in a numerical model for laser transitions emitting at 2335 nm and 1865 nm.

  4. Luminescence and microstructure of Sm{sup 2+} ions reduced by x-ray irradiation in Li{sub 2}O-SrO-B{sub 2}O{sub 3} glass

    SciTech Connect

    Huang Yanlin; Jiang, Chuanfang; Jang, Kiwan; Lee, Ho Sueb; Cho, Eunjin; Jayasimhadri, M.; Yi, Soung-Soo

    2008-06-01

    Sm{sup 3+}-doped Li{sub 2}O-SrO-B{sub 2}O{sub 3} glass sample was prepared by the conventional melt quenching method in air atmosphere. Sm{sup 2+} ions in this borate glass were obtained by x-ray irradiation reduction method. The as-prepared and x-ray-irradiated samples were investigated by photoluminescence spectrum and decay curve measurements. The dependence of Sm{sup 2+} luminescence intensity on the x-ray irradiation time was investigated. It is found that the conversion of Sm{sup 3+}{yields}Sm{sup 2+} after x-ray irradiation is efficient in this borate glass. Photostability of Sm{sup 2+} ions was evaluated by the photobleaching method. Furthermore, the induced optical absorption spectrum measurement after x-ray irradiation was performed. Thermoluminescence above room temperature was also studied after x-ray irradiation. The different kinds of defect structures and the reduction mechanism of Sm{sup 2+} ions in this borate glass were discussed. The microstructure of Sm ions in the Li{sub 2}O-SrO-B{sub 2}O{sub 3} glass was suggested. The proposed microstructure would be helpful to understand the reduction mechanism of Sm{sup 2+} ion in borate glasses.

  5. Magnetic properties and homogeneous distribution of Gd{sup 3+} ions in gadolinium molybdenum borate glass with high Gd{sub 2}O{sub 3} content

    SciTech Connect

    Suzuki, F.; Honma, T.; Doi, Y.; Hinatsu, Y.; Komatsu, T.

    2012-11-15

    Highlights: ► The magnetic susceptibility of Gd{sub 2}O{sub 3}–MoO{sub 3}–B{sub 2}O{sub 3} glass was examined in T = 1.8–300 K. ► The effective magnetic moment was μ{sub eff} = 7.87 μ{sub B}. ► The Weiss constant was θ = −0.7 K. ► Gd{sup 3+} ions are distributed homogeneously as paramagnetic ions down to T = 1.8 K. -- Abstract: The magnetic susceptibility and specific heat of 21.25Gd{sub 2}O{sub 3}–63.75MoO{sub 3}–15B{sub 2}O{sub 3} (mol%) glass showing the crystallization of ferroelastic β′-Gd{sub 2}(MoO{sub 4}){sub 3} crystals are examined in the temperature range of T = 1.8–300 K to clarify magnetic and distribution states of Gd{sup 3+} ions. The magnetic susceptibility obeys the Curie–Weiss law, giving the effective magnetic moment of μ{sub eff} = 7.87 μ{sub B} and the Weiss constant of θ = −0.7 K. Any peak such as λ-type anomaly is not observed in the temperature dependence of specific heat in T = 1.8–5 K. It is suggested that Gd{sup 3+} ions in the glass with a high Gd{sub 2}O{sub 3} content of 21.25 mol% are distributed homogeneously and randomly as paramagnetic ions down to T = 1.8 K without inducing any strong magnetic interaction. The present study suggests that glasses based on the MoO{sub 3}–B{sub 2}O{sub 3} system are good hosts for the homogeneous solubility of a large amount of rare-earth oxides.

  6. Influence of single and binary doping of strontium and lithium on in vivo biological properties of bioactive glass scaffolds

    NASA Astrophysics Data System (ADS)

    Khan, Pintu Kumar; Mahato, Arnab; Kundu, Biswanath; Nandi, Samit K.; Mukherjee, Prasenjit; Datta, Someswar; Sarkar, Soumya; Mukherjee, Jayanta; Nath, Shalini; Balla, Vamsi K.; Mandal, Chitra

    2016-09-01

    Effects of strontium and lithium ion doping on the biological properties of bioactive glass (BAG) porous scaffolds have been checked in vitro and in vivo. BAG scaffolds were prepared by conventional glass melting route and subsequently, scaffolds were produced by evaporation of fugitive pore formers. After thorough physico-chemical and in vitro cell characterization, scaffolds were used for pre-clinical study. Soft and hard tissue formation in a rabbit femoral defect model after 2 and 4 months, were assessed using different tools. Histological observations showed excellent osseous tissue formation in Sr and Li + Sr scaffolds and moderate bone regeneration in Li scaffolds. Fluorochrome labeling studies showed wide regions of new bone formation in Sr and Li + Sr doped samples as compared to Li doped samples. SEM revealed abundant collagenous network and minimal or no interfacial gap between bone and implant in Sr and Li + Sr doped samples compared to Li doped samples. Micro CT of Li + Sr samples showed highest degree of peripheral cancellous tissue formation on periphery and cortical tissues inside implanted samples and vascularity among four compositions. Our findings suggest that addition of Sr and/or Li alters physico-chemical properties of BAG and promotes early stage in vivo osseointegration and bone remodeling that may offer new insight in bone tissue engineering.

  7. Influence of single and binary doping of strontium and lithium on in vivo biological properties of bioactive glass scaffolds

    PubMed Central

    Khan, Pintu Kumar; Mahato, Arnab; Kundu, Biswanath; Nandi, Samit K.; Mukherjee, Prasenjit; Datta, Someswar; Sarkar, Soumya; Mukherjee, Jayanta; Nath, Shalini; Balla, Vamsi K.; Mandal, Chitra

    2016-01-01

    Effects of strontium and lithium ion doping on the biological properties of bioactive glass (BAG) porous scaffolds have been checked in vitro and in vivo. BAG scaffolds were prepared by conventional glass melting route and subsequently, scaffolds were produced by evaporation of fugitive pore formers. After thorough physico-chemical and in vitro cell characterization, scaffolds were used for pre-clinical study. Soft and hard tissue formation in a rabbit femoral defect model after 2 and 4 months, were assessed using different tools. Histological observations showed excellent osseous tissue formation in Sr and Li + Sr scaffolds and moderate bone regeneration in Li scaffolds. Fluorochrome labeling studies showed wide regions of new bone formation in Sr and Li + Sr doped samples as compared to Li doped samples. SEM revealed abundant collagenous network and minimal or no interfacial gap between bone and implant in Sr and Li + Sr doped samples compared to Li doped samples. Micro CT of Li + Sr samples showed highest degree of peripheral cancellous tissue formation on periphery and cortical tissues inside implanted samples and vascularity among four compositions. Our findings suggest that addition of Sr and/or Li alters physico-chemical properties of BAG and promotes early stage in vivo osseointegration and bone remodeling that may offer new insight in bone tissue engineering. PMID:27604654

  8. Influence of single and binary doping of strontium and lithium on in vivo biological properties of bioactive glass scaffolds.

    PubMed

    Khan, Pintu Kumar; Mahato, Arnab; Kundu, Biswanath; Nandi, Samit K; Mukherjee, Prasenjit; Datta, Someswar; Sarkar, Soumya; Mukherjee, Jayanta; Nath, Shalini; Balla, Vamsi K; Mandal, Chitra

    2016-01-01

    Effects of strontium and lithium ion doping on the biological properties of bioactive glass (BAG) porous scaffolds have been checked in vitro and in vivo. BAG scaffolds were prepared by conventional glass melting route and subsequently, scaffolds were produced by evaporation of fugitive pore formers. After thorough physico-chemical and in vitro cell characterization, scaffolds were used for pre-clinical study. Soft and hard tissue formation in a rabbit femoral defect model after 2 and 4 months, were assessed using different tools. Histological observations showed excellent osseous tissue formation in Sr and Li + Sr scaffolds and moderate bone regeneration in Li scaffolds. Fluorochrome labeling studies showed wide regions of new bone formation in Sr and Li + Sr doped samples as compared to Li doped samples. SEM revealed abundant collagenous network and minimal or no interfacial gap between bone and implant in Sr and Li + Sr doped samples compared to Li doped samples. Micro CT of Li + Sr samples showed highest degree of peripheral cancellous tissue formation on periphery and cortical tissues inside implanted samples and vascularity among four compositions. Our findings suggest that addition of Sr and/or Li alters physico-chemical properties of BAG and promotes early stage in vivo osseointegration and bone remodeling that may offer new insight in bone tissue engineering. PMID:27604654

  9. Morphology and orientation of β-BaB{sub 2}O{sub 4} crystals patterned by laser in the inside of samarium barium borate glass

    SciTech Connect

    Nishii, Akihito; Shinozaki, Kenji; Honma, Tsuyoshi; Komatsu, Takayuki

    2015-01-15

    Nonlinear optical β-BaB{sub 2}O{sub 4} crystal lines (β-BBO) were patterned in the inside of 8Sm{sub 2}O{sub 3}–42BaO–50B{sub 2}O{sub 3} glass by irradiations of continuous-wave Yb:YVO{sub 4} lasers with a wavelength of 1080 nm (power: P=0.8–1.0 W, scanning speed: S=0.2–2.5 μm/s), in which the laser focal position was moved gradually from the surface to the inside. The morphology, size, and orientation of β-BBO crystals were examined from polarization optical microscope and birefringence imaging observations. It was demonstrated that c-axis oriented β-BBO crystals with long lengths (e.g., 20 mm) were patterned in the inside of the glass. The morphology of β-BBO in the cross-section of lines was a rectangular shape with rounded corners, and the volume of β-BBO formed increased with increasing laser power and with decreasing laser scanning speed. The maximum depth in the inside from the surface for β-BBO patterning increased with increasing laser power, e.g., D{sub max}∼100 μm at P=0.8 W, D{sub max}∼170 μm at P=0.9 W, and D{sub max}∼200 μm at P=1 W. The present study proposes that the laser-induced crystallization opens a new door for applied engineering in glassy solids. - Graphical abstract: This figure shows the POM photographs for β-BaB{sub 2}O{sub 4} crystal lines patterned by cw Yb:YVO{sub 4} fiber laser irradiations with a laser power of P=0.8 W and a laser scanning speed S=2 μm/s in the glass. The laser focal point was moved gradually from the surface into the inside. The results shown in Fig. 1 demonstrate that it is possible to pattern highly oriented β-BaB{sub 2}O{sub 4} crystals even in the inside of glasses. - Highlights: • β-BaB{sub 2}O{sub 4} crystal lines were patterned in the inside of a glass by lasers. • Laser focal position was moved gradually from the surface to the inside. • Birefringence imaging was observed. • Morphology, size, and orientation of crystals were clarified. • Crystal lines with long lengths

  10. Carbon implanted waveguides in soda lime glass doped with Yb3+ and Er3+ for visible light emission

    NASA Astrophysics Data System (ADS)

    Vázquez, G. V.; Valiente, R.; Gómez-Salces, S.; Flores-Romero, E.; Rickards, J.; Trejo-Luna, R.

    2016-05-01

    Channel waveguides were fabricated by carbon implantation in soda lime glass samples doped with Er3+ and Yb3+, exhibiting good confinement and both monomode and multimode behaviour at 633 nm. Excitation at near infrared (NIR) and ultraviolet (UV) spectral ranges were used in order to obtain anti-Stokes (upconversion) and Stokes (downshift) emission in the visible range, respectively. The characteristic green and red bands of Er3+ transitions were observed, showing the potential of Yb3+ and Er3+ co-doping for the generation of visible guided emission under NIR excitation.

  11. High-gain wavelength-selective amplification and cavity ring down spectroscopy in a fluoride glass erbium-doped microsphere.

    PubMed

    Rasoloniaina, A; Trebaol, S; Huet, V; Le Cren, E; Nunzi Conti, G; Serier-Brault, H; Mortier, M; Dumeige, Y; Féron, P

    2012-11-15

    We experimentally demonstrate a compact optical amplifier consisting of a rare-earth-doped whispering-gallery-mode microsphere coupled via a tapered fiber. A gain up to 20 dB is reported in an erbium-doped fluoride glass microsphere 135 μm in diameter. Below the amplification regime, the optical gain is used to compensate for unavoidable losses due to surface contamination or scattering. Quality factor as high as 2×10(9) has been measured by analyzing the transient response of the microsphere excited by a dynamically shifted frequency input signal. PMID:23164896

  12. Optical characterization of Nd(sup 3+) and Er(sup 3+) doped-lead-indium phosphate glasses.

    SciTech Connect

    Brito, T. B.; Vermelho, M. V. D.; Gouveia, E. A.; de Araujo, M. T.; Guedes, I.; Loong, C.-K.; Boatner, L. A.; Intense Pulsed Neutron Source; UFAL; UFC; ORNL

    2007-08-15

    In this work, Judd-Ofelt analysis is applied to rare-earth-doped lead-indium-phosphate glasses (RE-PbInPO{sub 4}, where RE=Er{sup 3+} and Nd{sup 3+}) in order to evaluate their potential as both glass laser systems and amplifier materials. The phenomenological Judd-Ofelt parameters {Omega}{sub (2)}, {Omega}{sub (4)}, and {Omega}{sub (6)} are determined for both rare-earth ions together with their quality factors and compared with the equivalent parameters for several other host glasses. The spontaneous emission probabilities and the lifetimes of the Nd{sup 3+} {sup 4}F{sub 3/2} laser transitions are determined and analyzed as a function of the optical quality factor. For Nd{sup 3+}-PbInPO{sub 4}, glass fluorescence emission (890, 1058, and 1330 nm) lines are observed. Highly efficient infrared-to-visible frequency up-conversion at 530, 550, and 670 nm as well as an intense infrared fluorescence emission ({approx}1540 nm) is observed in Er{sup 3+}-doped PbIn(PO{sub 4}) glasses pumped using 800 nm radiation excitation.

  13. Effect of boron doping on optical properties of sol-gel based nanostructured zinc oxide films on glass

    SciTech Connect

    Jana, Sunirmal; Vuk, Angela Surca; Mallick, Aparajita; Orel, Boris; Biswas, Prasanta Kumar

    2011-12-15

    Graphical abstract: Room temperature fine structured UV-vis PL emissions (a) as phonon replicas in 1 at.% boron doped film originated from LO phonon evidenced from Near Grazing Incidence Angle (NGIA) IR spectral study (b). Highlights: Black-Right-Pointing-Pointer Sol-gel based boron doped nanostructured ZnO thin films deposited on pure silica glass using crystalline boric acid as boron source. Black-Right-Pointing-Pointer Observed first time, room temperature fine structured PL emissions in 1 at.% doped film as phonon replicas originated from LO phonon (both IR and Raman active). Black-Right-Pointing-Pointer Boron doping controls the LO phonon energy in addition to visible reflection, band gap and grain size. Black-Right-Pointing-Pointer The films possessed mixed crystal phases with hexagonal as major phase. -- Abstract: Boron doped zinc oxide thin films ({approx}80 nm) were deposited onto pure silica glass by sol-gel dip coating technique from the precursor sol/solution of 4.0 wt.% equivalent oxide content. The boron concentration was varied from 0 to 2 at.% w.r.t. Zn using crystalline boric acid. The nanostructured feature of the films was visualized by FESEM images and the largest cluster size of ZnO was found in 1 at.% boron doped film (B1ZO). The presence of mixed crystal phases with hexagonal as major phase was identified from XRD reflections of the films. Particle size, optical band gap, visible specular reflection, room temperature photoluminescence (PL) emissions (3.24-2.28 eV), infra-red (IR) and Raman active longitudinal optical (LO) phonon vibration were found to be dependent on dopant concentration. For the first time, we report the room temperature fine structured PL emissions as phonon replicas originated from the LO phonon (both IR and Raman active) in 1 at.% boron doped zinc oxide film.

  14. Compositional investigation of ∼2 μm luminescence of Ho{sup 3+}-doped lead silicate glass

    SciTech Connect

    Liu, Xueqiang; Huang, Feifei; Gao, Song; Wang, Xin; Hu, Lili; Chen, Danping

    2015-11-15

    Graphical abstract: Ho{sup 3+}-doped lead silicate glass with lowest maximum phonon energy possesses highest ∼2 μm luminescence intensity. - Highlights: • With increment of lead oxide, maximum phonon energy in lead silicate glass decreased. • ∼2 μm luminescent intensity of Ho{sup 3+} increased with increment of lead oxide. • Lowest lead oxide content glass possesses highest quantum efficiency due to low maximum phonon energy. - Abstract: Lead silicate glass samples with varying lead oxide content were prepared in this study, and their luminescent properties were examined and analyzed. It was found that with increasing lead oxide content, the maximum phonon energies of the glass samples decreased, while their spontaneous transition probabilities first increased and then decreased. The influence of the spontaneous transition rate, A{sub 10}, and the multi-phonon relaxation rate, W{sub 10}, on the sample luminescent properties was analyzed using rate equations. As a result, it was found that with increasing lead oxide content, W{sub 10}/A{sub 10} decreased, while the quantum efficiency increased. Thus, the luminescent intensity at ∼2 μm increased in the glass samples with increased lead oxide content. The high luminescent intensity and long lifetime indicate that silicate glasses containing high levels of lead oxide could potentially be used in ∼2 μm lasers.

  15. Intensity dependence of Z-scan in semiconductor-doped glasses for separation of third and fifth order contributions in the below band gap region

    NASA Astrophysics Data System (ADS)

    Bindra, K. S.; Oak, S. M.; Rustagi, K. C.

    1999-09-01

    The limitations of the Z-scan method in separating the third order and fifth order nonlinearities in dilute nonlinear systems like semiconductor-doped glasses are discussed. By simulating various experimental situations, we show that rather sensitive detection is required in such cases to separate the two contributions. The earlier Z-scan data on semiconductor doped glasses is shown to be consistent with a dominantly fifth order nonlinearity.

  16. Morphology and orientation of β-BaB2O4 crystals patterned by laser in the inside of samarium barium borate glass

    NASA Astrophysics Data System (ADS)

    Nishii, Akihito; Shinozaki, Kenji; Honma, Tsuyoshi; Komatsu, Takayuki

    2015-01-01

    Nonlinear optical β-BaB2O4 crystal lines (β-BBO) were patterned in the inside of 8Sm2O3-42BaO-50B2O3 glass by irradiations of continuous-wave Yb:YVO4 lasers with a wavelength of 1080 nm (power: P=0.8-1.0 W, scanning speed: S=0.2-2.5 μm/s), in which the laser focal position was moved gradually from the surface to the inside. The morphology, size, and orientation of β-BBO crystals were examined from polarization optical microscope and birefringence imaging observations. It was demonstrated that c-axis oriented β-BBO crystals with long lengths (e.g., 20 mm) were patterned in the inside of the glass. The morphology of β-BBO in the cross-section of lines was a rectangular shape with rounded corners, and the volume of β-BBO formed increased with increasing laser power and with decreasing laser scanning speed. The maximum depth in the inside from the surface for β-BBO patterning increased with increasing laser power, e.g., Dmax~100 μm at P=0.8 W, Dmax~170 μm at P=0.9 W, and Dmax~200 μm at P=1 W. The present study proposes that the laser-induced crystallization opens a new door for applied engineering in glassy solids.

  17. X-ray absorption fine structure of aged, Pu-doped glass and ceramic waste forms

    NASA Astrophysics Data System (ADS)

    Hess, N. J.; Weber, W. J.; Conradson, S. D.

    1998-04-01

    X-ray absorption spectroscopic (XAS) studies were performed on three compositionally identical, Pu-doped, borosilicate glasses prepared 15 years ago at different α-activities by varying the 239Pu/ 238Pu isotopic ratio. The resulting α-activities ranged from 1.9×10 7 to 4.2×10 9 Bq/g and have current, accumulated doses between 8.8×10 15 to 1.9×10 18 α-decays/g. Two ceramic, polycrystalline zircon (ZrSiO 4) samples prepared 16 years ago with 10.0 wt% Pu was also investigated. Varying the 239Pu/ 238Pu isotopic ratio in these samples resulted in α-activities of 2.5×10 8 and 5.6×10 10 Bq/g and current, accumulated doses of 1.2×10 17 and 2.8×10 19 α-decays/g. The multicomponent composition of the waste forms permitted XAS investigations at six absorption edges for the borosilicate glass and at three absorption edges for the polycrystalline zircons. For both waste forms, analysis of extended X-ray absorption fine structure (EXAFS) and X-ray absorption near edge structure (XANES) spectra indicates that the local environment around the cations exhibits different degrees of disorder as a result of the accumulated α-decay dose. In general, cations with short cation-oxygen bonds show little effect from self-radiation whereas cations with long cation-oxygen bonds show a greater degree of disorder with accumulated α-decay dose.

  18. Effect of co-doping Tm3+ ions on the emission properties of Dy3+ ions in tellurite glasses

    NASA Astrophysics Data System (ADS)

    Sasikala, T.; Rama Moorthy, L.; Mohan Babu, A.; Srinivasa Rao, T.

    2013-07-01

    The present work reports the absorption, photoluminescence and decay properties of singly doped Dy3+ and co-doped Dy3+/Tm3+ ions in TeO2+ZnO+K2O+CaO (TZKC) glasses prepared by the melt quenching technique. The glassy nature of the host glass has been confirmed by X-ray diffraction analysis and the primary vibrational modes were determined from the Raman spectrum. Judd-Ofelt (JO) analysis has been used to calculate the radiative transition rates, branching ratios and radiative lifetime of the emitting 4F9/2 state. The effect of co-doping of different concentrations of Tm3+ ions on the emission properties of Dy3+ ions has been investigated. The decay profiles of the 4F9/2 level were fitted to double exponential as well as Inokuti-Hirayama (IH) model to determine the energy transfer rates between Dy3+ and Tm3+ ions. The energy transfer rates found to increase with the increase of Tm3+ ions concentration. The chromaticity coordinates and color purity of the emitted light for all glasses were determined.

  19. 2.7 μm fluorescence and energy transfer in Er{sup 3+} doped germanosilicate glasses

    SciTech Connect

    Wei, Tao; Jing, Xufeng; Tian, Ying; Chen, Fangze; Wang, Fengchao; Xu, Shiqing

    2014-06-01

    Highlights: • Novel Er{sup 3+} doped germanosilicate glasses were synthesized. • Excellent thermal stability and 2.7 μm emission properties were obtained. • High A{sub rad} (33.75 s{sup −1}) and emission cross section (1.90 × 10{sup −20} cm{sup 2}) were achieved. • A reasonable energy transfer mechanism was put forward. - Abstract: 2.7 μm fluorescence has been achieved for the first time in Er{sup 3+} doped novel germanosilicate glasses. Thermal stability, spectroscopic properties and energy transfer mechanism have been investigated in detail. Moreover, the spontaneous transition probability (A{sub rad}) and emission cross section of samples were calculated and analyzed. The prepared Er{sup 3+} doped germanosilicate glasses possessing excellent thermal stability, high A{sub rad} (33.75 s{sup −1}) and emission cross section of 2.7 μm (1.90 × 10{sup −20} cm{sup 2}) provide a new material for the realization of mid-infrared fiber lasers.

  20. Thermo-optic characterization of neodymium/nickel doped silica glasses prepared via sol-gel route.

    PubMed

    Manuel, Ancy; Kumar, B Rajesh; Basheer, N Shemeena; Kumari, B Syamala; Paulose, P I; Kurian, Achamma; George, Sajan D

    2012-12-01

    Intrinsic as well as rare earth (Neodymium) doped silica glasses with various molar ratio of dopant and a metallic (Nickel) co-dopant is prepared via sol-gel route. The structural characterization of the sample is carried out using X-ray diffraction and Fourier Transform Infrared Spectroscopy. The influence of dopant and doping concentration on the optical properties of silica matrix is investigated via UV-VIS absorption spectroscopy. Effect of dopant on thermal effusivity value of the host matrix is carried out by laser induced open cell photoacoustic technique. Analysis of the results showed that doping affect the thermal effusivity value and results are interpreted in terms of structural modification of the lattice and phonon assisted heat transport mechanism.

  1. Electrochromic characteristics of niobium-doped titanium oxide film on indium tin oxide/glass by liquid phase deposition

    NASA Astrophysics Data System (ADS)

    Lee, Ming-Kwei; Lee, Chia-Jung

    2015-10-01

    Ammonium hexafluorotitanate and boric acid aqueous solutions were used as precursors for the growth of titanium oxide films on indium tin oxide (ITO)/glass substrate. For as-grown titanium oxide film used in an electrochromic device, Li+ ions from electrolyte will be trapped to hydroxyl groups and degrade the electrochromic durability during the cyclic voltammogram characterization. For niobium doped titanium oxide film, lower growth rate from more HF incorporation from the niobium doped solution and rougher surface morphology from the formation of nanocrystals were obtained. However, niobium doping reduces hydroxyl groups and the electrochromic durability is enhanced from 5 × 103 to 1 × 104 times. The transmittance is enhanced from 37 to 51% at the wavelength of 550 nm.

  2. Luminescence of Eu(3+) doped SiO2 Thin Films and Glass Prepared by Sol-gel Technology

    NASA Technical Reports Server (NTRS)

    Castro, Lymari; Jia, Weiyi; Wang, Yanyun; Santiago, Miguel; Liu, Huimin

    1998-01-01

    Trivalent europium ions are an important luminophore for lighting and display. The emission of (5)D0 to (7)F2 transition exhibits a red color at about 610 nm, which is very attractive and fulfills the requirement for most red-emitting phosphors including lamp and cathode ray phosphorescence materials. Various EU(3+) doped phosphors have been developed, and luminescence properties have been extensively studied. On the other hand, sol-gel technology has been well developed by chemists. In recent years, applications of this technology to optical materials have drawn a great attention. Sol-gel technology provides a unique way to obtain homogeneous composition distribution and uniform doping, and the processing temperature can be very low. In this work, EU(3+) doped SiO2 thin films and glasses were prepared by sol-gel technology and their spectroscopic properties were investigated.

  3. Luminescent properties of Eu{sup 2+}-doped BaGdF{sub 5} glass ceramics a potential blue phosphor for ultra-violet light-emitting diode

    SciTech Connect

    Zhang, Weihuan; Zhang, Yuepin Ouyang, Shaoye; Zhang, Zhixiong; Wang, Qian; Xia, Haiping

    2015-01-14

    Eu{sup 2+} doped transparent oxyfluoride glass ceramics containing BaGdF{sub 5} nanocrystals were successfully fabricated by melt-quenching technique under a reductive atmosphere. The structure of the glass and glass ceramics were investigated by differential scanning calorimetry, X-ray diffraction (XRD), and transmission electron microscopy (TEM). The luminescent properties were investigated by transmission, excitation, and emission spectra. The decay time of the Gd{sup 3+} ions at 312 nm excited with 275 nm were also investigated. The results of XRD and TEM indicated the existence of BaGdF5 nanocrystals in the transparent glass ceramics. The excitation spectra of Eu{sup 2+} doped glass ceramics showed an excellent overlap with the main emission region of an ultraviolet light-emitting diode (UV-LED). Compared with the as-made glass, the emission of glass ceramics is much stronger by a factor of increasing energy transfer efficiency from Gd{sup 3+} to Eu{sup 2+} ions, the energy transfer efficiency from Gd{sup 3+} to Eu{sup 2+} ions was discussed. In addition, the chromaticity coordinates of glass and glass ceramics specimens were also discussed, which indicated that the Eu{sup 2+} doped BaGdF{sub 5} glass ceramics may be used as a potential blue-emitting phosphor for UV-LED.

  4. Correlation of EMR and optical spectroscopy data for Cr3+ and Mn2+ ions doped into yttrium aluminum borate YAl3(BO3)4 crystal - Extracting low symmetry aspects

    NASA Astrophysics Data System (ADS)

    Rudowicz, Czesław; Gnutek, Paweł; Açıkgöz, Muhammed

    2015-08-01

    In this study, the crystal field analysis for Cr3+ and Mn2+ ions doped into yttrium aluminum borate YAl3(BO3)4, for short YAB, crystal has been carried out to complement earlier study of the zero-field splitting (ZFS) parameters (ZFSPs). This analysis utilizes data on the distortion models obtained from analysis of the ZFSPs obtained experimentally by EMR for Cr3+ and Mn2+ ions at the Y3+ and Al3+ sites in YAB. This approach enables to verify and enhance reliability of the ZFSP modeling based on superposition model (SPM) analysis and the distortion models predicted previously. Subsequently, modeling of the crystal field parameters (CFPs) based on SPM analysis is carried out for Cr3+ and Mn2+ ions located at possible cation sites in YAB. The SPM predicted CFP values serve as input for the Crystal Field Analysis (CFA) package to calculate the CF energy levels. The predicted physical ZFS of the ground spin state, i.e. the 4A2 state for Cr3+ ion and the 6S state Mn2+ ions, enable calculation of the theoretical ZFSP values, D and D & (a-F), respectively, using the microscopic spin Hamiltonian (MSH) module in the CFA package. In this way, data on the distortions around the Cr3+ centers in YAB (and to a certain extent also for Mn2+ centers) obtained using the ZFSP data from EMR measurements may be correlated with data on the CF energy levels measured by optical spectroscopy. This modeling approach uncovers certain incompatibilities in the existing data for Cr3+:YAB, which call for reanalysis of the previous assignments of the energy levels observed in optical spectra and more accurate experimental data.

  5. Phosphate content influence on structural, spectroscopic, and lasing properties of Er,Yb-doped potassium-lanthanum phosphate glasses

    NASA Astrophysics Data System (ADS)

    Šulc, Jan; Švejkar, Richard; Jelínková, Helena; Nejezchleb, Karel; Nitsch, Karel; Cihlář, Antonín; Král, Robert; Ledinský, Martin; Fejfar, Antonn; Rodová, Miroslava; Zemenová, Petra; Nikl, Martin

    2016-04-01

    The influence of the phosphorus pentoxide (P2O5) content on the material properties of Er,Yb-doped potassium-lanthanum phosphate glass was studied. Glass samples of the following nominal composition 35.0K2O-6.8Yb2O3-8.0La2O3-0.2Er2O3-50.0P2O5 (in mol%) were prepared from starting materials mixed with five additional amounts of P2O5 (0, 7.5, 15.0, 30.0, and 45.0 mol% related to the nominal glass composition). The P2O5 addition influence on properties of prepared glasses was studied using Raman, absorption, and fluorescence spectroscopy. The glass residual IR absorption and Judd-Ofelt intensity parameters together with absorption and emission cross sections were estimated. The results showed the increasing polymerization of glass and the P-O bond shortening with P2O5 content increase. The spectroscopy of Er and Yb ions was affected only marginally by the glass composition. It was found that fluorescence decay time corresponding to upper-laser-level I increased with the decrease of P2O5 content in the glasses, which was related to increasing OH- contamination of the glass. The laser action at 1.53 μm under 975-nm pulsed laser diode pumping was successfully demonstrated. Low threshold and laser slope efficiency up to 21% in respect to absorbed pumping power were obtained.

  6. Preliminary evaluation of therapeutic ion release from Sr-doped zinc-silicate glass ceramics.

    PubMed

    Looney, Mark; O'Shea, Helen; Boyd, Daniel

    2013-01-01

    Bioactive and degradable porous bioceramics play an important role in many clinical situations. Porosity is essential to the performance of a material that is proposed to be used as an implantable osseous scaffold. Scaffolds provide a three dimensional support and template to osseous integration and vascularization. Combining the porosity of a scaffold with the ability of the scaffold material to deliver therapeutic ions to the site of implantation goes some way towards developing an ideal bone graft. A series of strontium-doped zinc silicate (Ca-Sr-Na-Zn-Si) glass ceramics scaffoldswere developed, whose porosity was measured to be between 93% and 96%, which is advantageous in terms of osseous integration and vascularization. The levels of Zn(2+) and Sr(2+) detected as a result of degradation of the crystalline phases were found to be 1.4-600 parts per million (ppm) and 0-583 ppm, respectively. The levels detected correlate well with the levels of Sr(2+) and Zn(2+)ions typically associated with clinical benefits, including antibacterial efficacy, osteoblastic differentiation and impaired osteoclastic resorption.

  7. White light generation in Tb3+/Eu3+/Dy3+ triply-doped Zn(PO3)2 glass

    NASA Astrophysics Data System (ADS)

    Meza-Rocha, A. N.; Lozada-Morales, R.; Speghini, A.; Bettinelli, M.; Caldiño, U.

    2016-01-01

    A spectroscopic investigation of Tb3+/Eu3+/Dy3+ triply-doped Zn(PO3)2 glass focused on generation of white light is performed through photoluminescence spectra and decay time measurements. The white light emission obtained in the glass phosphor shows excitation wavelength dependent tunable tonality: neutral white (0.385, 0.441) of 4250 K and warm white (0.417, 0.412) of 3429 K, upon 445 and 322 nm excitations, respectively. A quantum yield of 26.1 ± 1.2% is attained upon Dy3+ excitation at 445 nm. The white luminescence is due mainly to terbium 5D4 → 7F5, dysprosium 4F9/2 → 6H15/2,13/2 and europium 5D0 → 7F2 transitions. It is demonstrated that non-radiative energy transfers Dy3+ to Tb3+ and Eu3+, and Tb3+ to Eu3+, take place in the glass phosphor excited at 445 or 322 nm. Tb3+/Eu3+/Dy3+ triply-doped Zn(PO3)2 glass, excited by AlGaN (322 nm) or InGaN (445 nm) LEDs, could then be appropriated for solid state lighting technology as neutral or warm white light phosphors.

  8. Effects of Mg and Zn on the surface of doped melt-derived glass for biomaterials applications

    NASA Astrophysics Data System (ADS)

    Dietrich, E.; Oudadesse, H.; Lucas-Girot, A.; Le Gal, Y.; Jeanne, S.; Cathelineau, G.

    2008-11-01

    Bioactive glasses in the system SiO 2-CaO-Na 2O-P 2O 5 were synthesized pure and doped with magnesium or zinc by melt-derived method. The bioactivity was studied during in vitro assays: the ability of hydroxycarbonate apatite (HCA) layer to form on the glass surface was examined after contact with simulated body fluid (SBF). The X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM) studies were performed before and after immersion in vitro assays. The SBF solutions were also analyzed using inductively coupled plasma-optical emission spectroscopy (ICP-OES). Introduction of magnesium and zinc as trace element induces several modifications on the observed phenomena at the glass surface and in SBF solution after immersion of the samples. The chemical durability of the glasses, the formation of the silica-rich layer and the crystallization of the HCA layer were affected, but not present the same modifications as the introduced doping element.

  9. Control of the local devitrification on oxyfluoride glass doped with Er{sup 3+} ions under diode laser irradiation

    SciTech Connect

    Gonzalez-Perez, S.; Martin, I. R.; Jaque, D.; Haro-Gonzalez, P.; Capuj, N.

    2010-11-15

    Temperature control of the devitrification process in an erbium doped oxyfluoride glass under laser irradiation is reported. The green upconversion emissions around 525 and 545 nm originated from the thermalized {sup 2}H{sub 11/2} and {sup 4}S{sub 3/2} levels were studied when the glass structure changes to glass ceramic during irradiation with a laser beam. Power dependence of the fluorescence intensity ratio was used to determine the temperature of the irradiated zone. The transition from glass to glass ceramic takes place under 2300 mW of laser power with an estimated temperature around 783 K. This result agrees with the one obtained in the samples devitrified under conventional furnace treatment. Therefore, the estimation of the temperature of the irradiated zone through the fluorescence intensity ratio method allows a controlled devitrification. Moreover, an irradiated line has been written in the glass showing an important diffusion of the Pb{sup 2+} and F{sup -} ions. These results confirm that nanocrystals have been created due to the laser action.

  10. NIR fluorescence studies of Neodymium ions doped sodium fluoroborate glasses for 1.06μm laser applications.

    PubMed

    Madhukar Reddy, C; Vijaya, N; Deva Prasad Raju, B

    2013-11-01

    The concentration dependent luminescence properties of Nd(3+) ions doped lead calcium zinc sodium fluoroborate (LCZSFB) glasses were prepared via a melt quenching technique and reported through optical absorption, NIR luminescence and lifetime measurements. The optical transition properties of Nd(3+) ions have been analyzed using Judd-Ofelt theory. The present glasses have high stimulated emission cross - sections, entail that they have high potential laser applications. The decay curves of all the glasses show single exponential behavior. The discrepancy between the experimental and calculated lifetimes of emitting level was ascribed to energy transfer through cross-relaxation. The estimated values of radiative and saturation intensity of (4)F3/2→(4)I11/2 transition indicates the favorable lasing action at 1.06μm.

  11. Origins of the broadening in 1.5 μm emission of Er3+-doped glasses

    NASA Astrophysics Data System (ADS)

    Dousti, M. Reza

    2015-11-01

    The broadband emission (4I13/2 → 4I15/2) of the Er3+-doped glasses has been always an attractive topic of research due to its explicit role in the progress of optical fibers science and technology. Few characteristics, such as the full-width at half-maximum, shape and excited state lifetime of this band are determinant parameters to obtain practically appropriate materials for high-tech applications. In this work, the broadening of the latter near-infrared emission of erbium ions, centered around 1.53 μm in C-band region, is briefly discussed as a function of the host glass, glass modifiers, temperature and thickness of the sample, excitation power and energy, as well as the concentration of the dopant.

  12. Spectrometric analysis of different fluorophosphate glasses doped with Sm{sup 3+} ions for reddish-orange laser emission

    SciTech Connect

    Babu, S. Balakrishna, A. Ratnakaram, Y. C.

    2014-04-24

    Optical properties of Sm{sup 3+} doped different fluorophosphate glasses have been synthesized and discussed. The J- O intensity parameters Ω{sub λ} (λ= 2, 4, 6) from absorption spectra have been evaluated. No sharp edges are found in the absorption spectra, which confirm amorphous nature of present glass matrices. Various radiative parameters have been obtained from luminescence spectra for excited states to corresponding {sup 4}G{sub 5/2}→{sup 6}H{sub 5/2}, {sup 6}H{sub 7/2}, {sup 6}H{sub 9/2} and {sup 6}H{sub 11/2} transitions. The nature of decay curve analysis was performed for the {sup 4}G{sub 5/2} level. These glasses are expected to give interesting application in field of optical devices.

  13. Lasing effects in new Nd3+-doped TeO2-Nb2O5-WO3 bulk glasses

    NASA Astrophysics Data System (ADS)

    Carreaud, J.; Labruyère, A.; Dardar, H.; Moisy, F.; Duclère, J.-R.; Couderc, V.; Bertrand, A.; Dutreilh-Colas, M.; Delaizir, G.; Hayakawa, T.; Crunteanu, A.; Thomas, P.

    2015-09-01

    This paper demonstrates for the first time continuous wave (cw) and pulsed lasing effects in a 75TeO2-20NbO2.5-5WO3 glass doped with 1 mol.% in Nd3+. It is divided into two parts: The first part treats all the aspects related to the elaboration and the characterization of the materials. Thus, glasses elaborated within the TeO2-Nb2O5-WO3 ternary system show a rather high glass transition temperature Tg ∼ 375 °C, with an excellent thermal stability of ∼160 °C. Compared to glasses synthesized in either TeO2-Nb2O5 or TeO2-WO3 binary systems, glasses fabricated within such system show improved mechanical performances, with larger Young's modulus values. The structural characteristics of the samples, studied by Raman spectroscopy, are also presented. Linear optical properties (refractive index and extinction coefficient) are accessed by spectroscopic ellipsometry. As well, the optical transmission of the various bulk glasses is measured, in the case of both uncoated and coated glasses. In particular, specific anti-reflective coatings at 808 nm (laser diode pump wavelength) and 1064 nm (laser emission wavelength) are respectively deposited on the two surfaces of the sample in order to minimize the losses due to Fresnel reflections at the two glass/air interfaces. In addition, another specific surface treatment (Rmax at 1064 nm) was employed to serve as the back mirror of the laser cavity. The optical transmission data testified to the real efficiency of all these coatings. Finally, the photoluminescence properties (emission and excitation spectra, and luminescence decay curve) of the Nd3+-doped glasses, measured at room temperature for bulk samples, and as a function of temperature for powder glasses, are discussed. The second part is focused on evidencing (cw) and pulsed lasing effects in such coated bulk lasers. Cylindric samples of only a few millimeters in height and in diameter were tested and led to a laser emission around 1064 nm, characterized by a very low

  14. Interplay of anisotropy and disorder in the doping-dependent melting and glass transitions of vortices in Bi2Sr2CaCu2O 8+delta.

    PubMed

    Beidenkopf, H; Verdene, T; Myasoedov, Y; Shtrikman, H; Zeldov, E; Rosenstein, B; Li, D; Tamegai, T

    2007-04-20

    We study the oxygen doping dependence of the equilibrium first-order melting and second-order glass transitions of vortices in Bi2Sr2CaCu2O 8+delta. Doping affects both anisotropy and disorder. Anisotropy scaling is shown to collapse the melting lines only where thermal fluctuations are dominant. Yet, in the region where disorder breaks that scaling, the glass lines are still collapsed. A quantitative fit to melting and replica symmetry-breaking lines of a 2D Ginzburg-Landau model further reveals that disorder amplitude weakens with doping, but to a lesser degree than thermal fluctuations, enhancing the relative role of disorder.

  15. Optical characterization, luminescence properties of Er3+ and Er3+/Yb3+ co-doped tellurite glasses for broadband amplification

    NASA Astrophysics Data System (ADS)

    Meruva, Seshadri; Carlos, Barbosa Luiz; Alberto Peres, Ferencz Junior Julio

    2014-03-01

    In the present paper, optical absorption and emission spectra and luminescence decay lifetimes of different concentrations, 0.1, 0.3, 0.5, 0.7 and 1.0 mol% of Er3+ and 0.1Er3+/0.5Yb3+ co-doped tellurite glasses (TeO2-Bi2O3-ZnONb2O5) were reported. Judd-Ofelt intensity parameters were determined and used to calculate spontaneous radiative transition probabilities (Arad), radiative lifetimes (τR), branching ratios (β) and stimulated emission cross-sections (σP) for certain emission transitions. NIR emission at 1.5μm and up-conversion spectra of Er3+ and Er3+/Yb3+ co-doped tellurite glasses were measured under excitation wavelength of 980 nm. The absorption, emission and gain cross-sections for 4I13/2→4I15/2 transition of Er3+ are determined. The peak emission cross-section of this transition is found to be higher (9.95×10-21 cm2) for 0.1 mol% of Er3+ and lower (6.81×10-21 cm2) for 1.0 mol% of Er3+ doped tellurite glasses, which is comparable to other oxide glasses. The larger peak emission cross-section for lower concentration of Er3+ is due to the high refractive index of glass matrix (2.1547), relation established from Judd-Ofelt theory. The observed full-widths at half maxima (FWHM) for lower and higher concentrations of Er3+ are 64nm and 96 nm respectively. The larger values of FWHM and peak emission cross-sections are potentially useful for optical amplification processes in the design of Erbium doped fiber amplifiers (EDFs). Under 980 nm excitation three strong up-conversion bands were observed at 530nm, 546nm and 665nm. The pump power dependent intensities and mechanisms involved in the up-conversion process have been studied. The luminescence decay profiles for 4I13/2 level were reported for all glass matrices.

  16. Effect of B 2O 3 on the fluorescence of Er-doped Ge-B-P-SiO 2 glasses for waveguide amplifier

    NASA Astrophysics Data System (ADS)

    Cho, Kang ill; Cho, Ki Hyun; Cho, Seung Hyun; Shin, Dong Wook

    2006-05-01

    Er 3+-doped silica glasses were prepared with similar composition to the waveguide core film of silica planar lightwave circuit (PLC) and tested for the basic photoluminescence characteristics to investigate the influence of B-doping. In the material viewpoint, the major difference between conventional fiber amplifier and waveguide amplifier is the chemical composition of host glass, especially B 2O 3. Er-doped silica bulk glasses were prepared with various B 2O 3 concentrations by melt and quenching method and waveguide films were prepared by flame hydrolysis deposition. Fluorescence spectra were measured for both type of specimen to clarify the effect of B 2O 3 and form of Er on basic amplification characteristics. According to the results of the fluorescence measurements, we could confirm the depression of the concentration quenching of Er ions by the doping of B 2O 3 and this is believed to be due to the formation of 4-coordinated boron in silica network.

  17. Spontaneous and strong multi-layer graphene n-doping on soda-lime glass and its application in graphene-semiconductor junctions

    DOE PAGESBeta

    Dissanayake, D. M. N. M.; Ashraf, A.; Dwyer, D.; Kisslinger, K.; Zhang, L.; Pang, Y.; Efstathiadis, H.; Eisaman, M. D.

    2016-02-12

    Scalable and low-cost doping of graphene could improve technologies in a wide range of fields such as microelectronics, optoelectronics, and energy storage. While achieving strong p-doping is relatively straightforward, non-electrostatic approaches to n-dope graphene, such as chemical doping, have yielded electron densities of 9.5 × 1012 e/cm2 or below. Furthermore, chemical doping is susceptible to degradation and can adversely affect intrinsic graphene’s properties. Here we demonstrate strong (1.33 × 1013 e/cm2), robust, and spontaneous graphene n-doping on a soda-lime-glass substrate via surface-transfer doping from Na without any external chemical, high-temperature, or vacuum processes. Remarkably, the n-doping reaches 2.11 × 1013more » e/cm2 when graphene is transferred onto a p-type copper indium gallium diselenide (CIGS) semiconductor that itself has been deposited onto soda-lime-glass, via surface-transfer doping from Na atoms that diffuse to the CIGS surface. Using this effect, we demonstrate an n-graphene/p-semiconductor Schottky junction with ideality factor of 1.21 and strong photo-response. As a result, the ability to achieve strong and persistent graphene n-doping on low-cost, industry-standard materials paves the way toward an entirely new class of graphene-based devices such as photodetectors, photovoltaics, sensors, batteries, and supercapacitors.« less

  18. Spontaneous and strong multi-layer graphene n-doping on soda-lime glass and its application in graphene-semiconductor junctions.

    PubMed

    Dissanayake, D M N M; Ashraf, A; Dwyer, D; Kisslinger, K; Zhang, L; Pang, Y; Efstathiadis, H; Eisaman, M D

    2016-01-01

    Scalable and low-cost doping of graphene could improve technologies in a wide range of fields such as microelectronics, optoelectronics, and energy storage. While achieving strong p-doping is relatively straightforward, non-electrostatic approaches to n-dope graphene, such as chemical doping, have yielded electron densities of 9.5 × 10(12) e/cm(2) or below. Furthermore, chemical doping is susceptible to degradation and can adversely affect intrinsic graphene's properties. Here we demonstrate strong (1.33 × 10(13) e/cm(2)), robust, and spontaneous graphene n-doping on a soda-lime-glass substrate via surface-transfer doping from Na without any external chemical, high-temperature, or vacuum processes. Remarkably, the n-doping reaches 2.11 × 10(13) e/cm(2) when graphene is transferred onto a p-type copper indium gallium diselenide (CIGS) semiconductor that itself has been deposited onto soda-lime-glass, via surface-transfer doping from Na atoms that diffuse to the CIGS surface. Using this effect, we demonstrate an n-graphene/p-semiconductor Schottky junction with ideality factor of 1.21 and strong photo-response. The ability to achieve strong and persistent graphene n-doping on low-cost, industry-standard materials paves the way toward an entirely new class of graphene-based devices such as photodetectors, photovoltaics, sensors, batteries, and supercapacitors.

  19. Spontaneous and strong multi-layer graphene n-doping on soda-lime glass and its application in graphene-semiconductor junctions.

    PubMed

    Dissanayake, D M N M; Ashraf, A; Dwyer, D; Kisslinger, K; Zhang, L; Pang, Y; Efstathiadis, H; Eisaman, M D

    2016-01-01

    Scalable and low-cost doping of graphene could improve technologies in a wide range of fields such as microelectronics, optoelectronics, and energy storage. While achieving strong p-doping is relatively straightforward, non-electrostatic approaches to n-dope graphene, such as chemical doping, have yielded electron densities of 9.5 × 10(12) e/cm(2) or below. Furthermore, chemical doping is susceptible to degradation and can adversely affect intrinsic graphene's properties. Here we demonstrate strong (1.33 × 10(13) e/cm(2)), robust, and spontaneous graphene n-doping on a soda-lime-glass substrate via surface-transfer doping from Na without any external chemical, high-temperature, or vacuum processes. Remarkably, the n-doping reaches 2.11 × 10(13) e/cm(2) when graphene is transferred onto a p-type copper indium gallium diselenide (CIGS) semiconductor that itself has been deposited onto soda-lime-glass, via surface-transfer doping from Na atoms that diffuse to the CIGS surface. Using this effect, we demonstrate an n-graphene/p-semiconductor Schottky junction with ideality factor of 1.21 and strong photo-response. The ability to achieve strong and persistent graphene n-doping on low-cost, industry-standard materials paves the way toward an entirely new class of graphene-based devices such as photodetectors, photovoltaics, sensors, batteries, and supercapacitors. PMID:26867673

  20. Spontaneous and strong multi-layer graphene n-doping on soda-lime glass and its application in graphene-semiconductor junctions

    PubMed Central

    Dissanayake, D. M. N. M.; Ashraf, A.; Dwyer, D.; Kisslinger, K.; Zhang, L.; Pang, Y.; Efstathiadis, H.; Eisaman, M. D.

    2016-01-01

    Scalable and low-cost doping of graphene could improve technologies in a wide range of fields such as microelectronics, optoelectronics, and energy storage. While achieving strong p-doping is relatively straightforward, non-electrostatic approaches to n-dope graphene, such as chemical doping, have yielded electron densities of 9.5 × 1012 e/cm2 or below. Furthermore, chemical doping is susceptible to degradation and can adversely affect intrinsic graphene’s properties. Here we demonstrate strong (1.33 × 1013 e/cm2), robust, and spontaneous graphene n-doping on a soda-lime-glass substrate via surface-transfer doping from Na without any external chemical, high-temperature, or vacuum processes. Remarkably, the n-doping reaches 2.11 × 1013 e/cm2 when graphene is transferred onto a p-type copper indium gallium diselenide (CIGS) semiconductor that itself has been deposited onto soda-lime-glass, via surface-transfer doping from Na atoms that diffuse to the CIGS surface. Using this effect, we demonstrate an n-graphene/p-semiconductor Schottky junction with ideality factor of 1.21 and strong photo-response. The ability to achieve strong and persistent graphene n-doping on low-cost, industry-standard materials paves the way toward an entirely new class of graphene-based devices such as photodetectors, photovoltaics, sensors, batteries, and supercapacitors. PMID:26867673

  1. Spontaneous and strong multi-layer graphene n-doping on soda-lime glass and its application in graphene-semiconductor junctions

    NASA Astrophysics Data System (ADS)

    Dissanayake, D. M. N. M.; Ashraf, A.; Dwyer, D.; Kisslinger, K.; Zhang, L.; Pang, Y.; Efstathiadis, H.; Eisaman, M. D.

    2016-02-01

    Scalable and low-cost doping of graphene could improve technologies in a wide range of fields such as microelectronics, optoelectronics, and energy storage. While achieving strong p-doping is relatively straightforward, non-electrostatic approaches to n-dope graphene, such as chemical doping, have yielded electron densities of 9.5 × 1012 e/cm2 or below. Furthermore, chemical doping is susceptible to degradation and can adversely affect intrinsic graphene’s properties. Here we demonstrate strong (1.33 × 1013 e/cm2), robust, and spontaneous graphene n-doping on a soda-lime-glass substrate via surface-transfer doping from Na without any external chemical, high-temperature, or vacuum processes. Remarkably, the n-doping reaches 2.11 × 1013 e/cm2 when graphene is transferred onto a p-type copper indium gallium diselenide (CIGS) semiconductor that itself has been deposited onto soda-lime-glass, via surface-transfer doping from Na atoms that diffuse to the CIGS surface. Using this effect, we demonstrate an n-graphene/p-semiconductor Schottky junction with ideality factor of 1.21 and strong photo-response. The ability to achieve strong and persistent graphene n-doping on low-cost, industry-standard materials paves the way toward an entirely new class of graphene-based devices such as photodetectors, photovoltaics, sensors, batteries, and supercapacitors.

  2. Spectroscopic studies of Nd3+ doped lead tungsten tellurite glasses for the NIR emission at 1062 nm

    NASA Astrophysics Data System (ADS)

    Venkateswarlu, M.; Mahamuda, Sk.; Swapna, K.; Prasad, M. V. V. K. S.; Srinivasa Rao, A.; Mohan Babu, A.; Shakya, Suman; Vijaya Prakash, G.

    2015-01-01

    Lead Tungsten Tellurite (LTT) glasses doped with different concentrations of Nd3+ ions were prepared by using the melt quenching technique to study the absorption, emission and decay spectral profiles with an aim to understand the lasing potentialities of these glasses. From the absorption spectra, the Judd-Ofelt (J-O) parameters are evaluated and in turn used to calculate the transition probability (AR), total transition probability (AT), radiative lifetime (τR) and branching ratios (βR) for prominent emission levels of Nd3+. The emission spectra recorded for LTT glasses gives three emission transitions 4F3/2 → 4I9/2, 4F3/2 → 4I11/2 and 4F3/2 → 4I13/2 for which effective band widths (ΔλP) and stimulated emission cross-sections (σse) are evaluated. Branching ratios (βR) measured for all the LTT glasses show that 4F3/2 → 4I11/2 transition is quite suitable for lasing applications. The intensity of emission spectra increases with increase in the concentrations of Nd3+ up to 1.0 mol% and beyond concentration quenching is observed. Relatively higher emission cross-sections and branching ratios observed for the present LTT glasses over the reported glasses suggests the feasibility of using LTT glasses for infrared laser applications. From the absorption, emission and decay spectral measurements, it was found that 1.0 mol% of Nd3+ ion concentration is aptly suitable for LTT glasses to give a strong NIR laser emission at 1062 nm.

  3. Ce(3+)/Yb(3+)/Er(3+) triply doped bismuth borosilicate glass: a potential fiber material for broadband near-infrared fiber amplifiers.

    PubMed

    Chu, Yushi; Ren, Jing; Zhang, Jianzhong; Peng, Gangding; Yang, Jun; Wang, Pengfei; Yuan, Libo

    2016-01-01

    Erbium doped bismuth borosilicate (BBS) glasses, possessing the broadest 1.55 μm near infrared (NIR) emission band among oxide glasses, stand out as excellent fiber material for optical fiber amplifiers. In this work, we demonstrate that both broadened and enhanced NIR emission of Er(3+) can be obtained by sensibly combining the effects such as mixed glass former effect, phonon-assisted energy transfer (PAET) and de-excitation effect induced by codopant. Specially, by codoping CeO2 in a controlled manner, it leads to not only much improved optical quality of the glasses, enhanced NIR emission, but also significantly suppressed energy transfer up-conversion (ETU) luminescence which is detrimental to the NIR emission. Cerium incorporated in the glasses exists overwhelmingly as the trivalent oxidation state Ce(3+) and its effects on the luminescence properties of Er(3+) are discussed. Judd-Ofelt analysis is used to evaluate gain amplification of the glasses. The result indicates that Ce(3+)/Yb(3+)/Er(3+) triply doped BBS glasses are promising candidate for erbium doped fiber amplifiers. The strategy described here can be readily extended to other rare-earth ions (REs) to improve the performance of REs doped fiber lasers and amplifiers. PMID:27646191

  4. Ce(3+)/Yb(3+)/Er(3+) triply doped bismuth borosilicate glass: a potential fiber material for broadband near-infrared fiber amplifiers.

    PubMed

    Chu, Yushi; Ren, Jing; Zhang, Jianzhong; Peng, Gangding; Yang, Jun; Wang, Pengfei; Yuan, Libo

    2016-09-20

    Erbium doped bismuth borosilicate (BBS) glasses, possessing the broadest 1.55 μm near infrared (NIR) emission band among oxide glasses, stand out as excellent fiber material for optical fiber amplifiers. In this work, we demonstrate that both broadened and enhanced NIR emission of Er(3+) can be obtained by sensibly combining the effects such as mixed glass former effect, phonon-assisted energy transfer (PAET) and de-excitation effect induced by codopant. Specially, by codoping CeO2 in a controlled manner, it leads to not only much improved optical quality of the glasses, enhanced NIR emission, but also significantly suppressed energy transfer up-conversion (ETU) luminescence which is detrimental to the NIR emission. Cerium incorporated in the glasses exists overwhelmingly as the trivalent oxidation state Ce(3+) and its effects on the luminescence properties of Er(3+) are discussed. Judd-Ofelt analysis is used to evaluate gain amplification of the glasses. The result indicates that Ce(3+)/Yb(3+)/Er(3+) triply doped BBS glasses are promising candidate for erbium doped fiber amplifiers. The strategy described here can be readily extended to other rare-earth ions (REs) to improve the performance of REs doped fiber lasers and amplifiers.

  5. Spectroscopic and laser properties of Er{sup 3+} doped fluoro-phosphate glasses as promising candidates for broadband optical fiber lasers and amplifiers

    SciTech Connect

    Babu, S.; Seshadri, M.; Reddy Prasad, V.; Ratnakaram, Y.C.

    2015-10-15

    Highlights: • Erbium doped different fluoro-phosphate glasses are prepared and characterized. • Spectroscopic properties have been determined using Judd–Ofelt and Mc-Cumber theory. • Prominent laser transition Er{sup 3+}:{sup 4}I{sub 13/2} → {sup 4}I{sub 15/2} is observed at 1.53 μm. - Abstract: Different fluoro-phosphate glasses doped with 0.5 mol% Er{sup 3+} doped are prepared by melt quenching method. Both structural and spectroscopic properties have been characterized in order to evaluate their potential as both laser source and amplifier materials. Optical absorption measurements are carried out and analyzed through Judd–Ofelt and Mc-Cumber theories where spectroscopic parameters such as intensity parameters Ω{sub l} (λ = 2,4,6), transition probabilities, radiative lifetimes, stimulated absorption cross-sections and emission cross-sections at 1.5 μm have been evaluated for Er{sup 3+} doped different fluorophosphate glasses. The various luminescence and gain properties are explained from photoluminescence studies. The decay curve analysis have been done for obtaining the decay time constants of Er{sup 3+} excited level {sup 4}I{sub 13/2} in all the fluoro-phosphate glasses. The obtained results of each glass matrix are compared with the equivalent parameters for several other host glasses. These fluoro-phosphate glasses are found to be suitable candidates for laser and amplifier applications.

  6. Ce3+/Yb3+/Er3+ triply doped bismuth borosilicate glass: a potential fiber material for broadband near-infrared fiber amplifiers

    PubMed Central

    Chu, Yushi; Ren, Jing; Zhang, Jianzhong; Peng, Gangding; Yang, Jun; Wang, Pengfei; Yuan, Libo

    2016-01-01

    Erbium doped bismuth borosilicate (BBS) glasses, possessing the broadest 1.55 μm near infrared (NIR) emission band among oxide glasses, stand out as excellent fiber material for optical fiber amplifiers. In this work, we demonstrate that both broadened and enhanced NIR emission of Er3+ can be obtained by sensibly combining the effects such as mixed glass former effect, phonon-assisted energy transfer (PAET) and de-excitation effect induced by codopant. Specially, by codoping CeO2 in a controlled manner, it leads to not only much improved optical quality of the glasses, enhanced NIR emission, but also significantly suppressed energy transfer up-conversion (ETU) luminescence which is detrimental to the NIR emission. Cerium incorporated in the glasses exists overwhelmingly as the trivalent oxidation state Ce3+ and its effects on the luminescence properties of Er3+ are discussed. Judd-Ofelt analysis is used to evaluate gain amplification of the glasses. The result indicates that Ce3+/Yb3+/Er3+ triply doped BBS glasses are promising candidate for erbium doped fiber amplifiers. The strategy described here can be readily extended to other rare-earth ions (REs) to improve the performance of REs doped fiber lasers and amplifiers. PMID:27646191

  7. Energy level decay and excited state absorption processes in erbium-doped tellurite glass

    NASA Astrophysics Data System (ADS)

    Gomes, Laércio; Oermann, Michael; Ebendorff-Heidepriem, Heike; Ottaway, David; Monro, Tanya; Felipe Henriques Librantz, André; Jackson, Stuart D.

    2011-10-01

    The fundamental excited state decay processes relating to the 4I11/2 → 4I13/2 transition in singly Er3+-doped tellurite (TZNL) glass have been investigated in detail using time-resolved fluorescence spectroscopy. Selective laser excitation of the 4I11/2 energy level at 970 nm and selective laser excitation of the 4I13/2 energy level at 1485 nm has established that energy transfer upconversion by way of a dipole-dipole interaction between two excited erbium ions in the 4I13/2 level populates the 4I11/2 upper laser level of the 3 μm transition. This upconversion has been analyzed for Er2O3 concentrations between 0.5 mol. % and 2.2 mol. %. The 4I13/2 and 4I11/2 energy levels emit luminescence with peaks located at 1532 nm and 2734 nm, respectively, with radiative decay efficiencies of 65% and 6.8% for the higher (2.2 mol. %) concentration sample. The low 2.7 μm emission efficiency is due to the non-radiative decay bridging the 4I11/2 → 4I13/2 transition and energy transfer to the OH- groups in the glass. Excited state absorption was observed to occur from the 4I13/2 and 4I11/2 levels with peak absorptions occurring at 1550 nm and 971 nm, respectively. The decay time of the 4I11/2 excited state decreased with an increase in the Er3+ concentration, which related to energy transfer to OH- ions that had a measured concentration of 6.6 × 1018 cm-3. Results from numerical simulations showed that a population inversion is reached at a threshold pumping intensity of ˜80 kW cm-2 for a cw laser pump at 976 nm if [Er3+] ≥ 1.2 × 1021 cm-3 (or [Er2O3] ≥ 2.65 mol. %) without OH- impurities being present.

  8. Characteristics of solid-state batteries with zinc/cadmium halide-doped silver phosphate glasses as electrolytes

    NASA Astrophysics Data System (ADS)

    Das, S. S.; Baranwal, B. P.; Gupta, C. P.; Singh, Punita

    Several samples of ion-conducting silver phosphate glasses doped with zinc/cadmium halides are prepared and subjected to X-ray diffraction analysis, transference number measurement, and electrical conductivity studies. The percentage transference numbers of these glasses are found to lie between 98.3 and 99.3, which suggests that the glasses are essentially ionic conductors. The conductivity values range from 1.66×10 -2 to 8.66×10 -2 S cm -1 at 300 °C. Solid-state batteries using these glassy systems as electrolytes with the cell configurations Ag||Ag 2OP 2O 5(20%)Zn/CdX 2||(C+I 2) and Ag||Ag 2OP 2O 5(20%)Zn/CdX 2||(C+I 2+electrolyte) (where X is Cl, Br or I) have been fabricated and their discharge characteristics studied. Cells with undoped silver phosphate glasses as electrolytes have also been prepared and studied. The addition of Zn/CdX 2 to silver phosphate glass results in a substantial increase in the open-circuit voltage in the order MI 2>MBr 2>MCl 2 (where M is the dopant cation). Cells with Ag||Ag 2OP 2O 5(20%)Zn/CdI 2||(C+I 2+electrolyte) deliver the best performance.

  9. Intense 1.6 μm fluorescence of Nd{sup 3+} doped cadmium bismuth silicate glasses

    SciTech Connect

    Pal, I. Agarwal, A. Sanghi, S.; Bhardwaj, S.; Sanjay

    2014-04-24

    In this work, Judd-Ofelt analysis is applied to rare-earth (RE = Nd{sup 3+}) doped cadmium bismuth silicate (20CdO⋅xSiO{sub 2}⋅(79.5−x)Bi{sub 2}O{sub 3}⋅0.5Nd{sub 2}O{sub 3} (CSBN)) glasses in order to evaluate their potential as well as both glass laser systems and optical materials. The phenomenological Judd-Ofelt parameters (Ω{sub 2}, Ω{sub 4}, Ω{sub 6}) are determined for RE ions with their quality factors and compared with the equivalent parameters for several other hosts. The calculated value of stimulated emission cross-section for {sup 4}F{sub 3/2}→{sup 4}I{sub 11/2} has high and varies 14.72×10{sup −20} to 9.66×10{sup −20} cm{sup 2} with Bi{sub 2}O{sub 3} content in the host glass. The results point out that the glass system is good candidate for the development of photonics devices which are operating near infrared spectral range. Further, the FTIR results reveal that the glasses have BiO{sub 6}, SiO{sub 4} and non-bridging oxygen as local structure.

  10. NIR luminescence studies on Er3+:Yb3+ co-doped sodium telluroborate glasses for lasers and optical amplifer applications

    NASA Astrophysics Data System (ADS)

    Annapoorani, K.; Murthy, N. Suriya; Marimuthu, K.

    2016-05-01

    Er3+:Yb3+ co-doped Sodium telluroborate glasses were prepared with the chemical composition (49.5-x)B2O3+25TeO2+5Li2CO3+10ZnO+10NaF+0.5Er2O3+xYb2O3 (where x= 0.1, 0.5, 1.0 and 2.0 in mol %) following the melt quenching technique. With the addition of Yb3+ ions into Er3+ ions in the prepared glasses, the absorption cross-section values were found to increase due to the effective energy transfer from 2F5/2 level of Yb3+ ions to the 4I11/2 level of Er3+ ions. The fluorescence around 1550 nm correspond to the 4I13/2→4I15/2 transition was observed under 980 nm pumping. Among the present glasses, integrated intensity was found to be higher for 1.0 mol% Yb3+ ion glass. The parameters such as stimulated emission cross- section, Gain bandwidth and quantum efficiency of the 4I13/2→4I15/2 transition was found to be higher for the NTBE1.0Y glass and the same is suggested for potential NIR lasers and optical amplifier applications.

  11. Investigation of mid-infrared emission characteristics and energy transfer dynamics in Er3+ doped oxyfluoride tellurite glass

    PubMed Central

    Chen, Fangze; Wei, Tao; Jing, Xufeng; Tian, Ying; Zhang, Junjie; Xu, Shiqing

    2015-01-01

    Er3+ doped oxyfluoride tellurite glasses have been prepared. Three Judd-Ofelt parameters Ωt (t = 2, 4, 6) and radiative properties are calculated for prepared glasses. Emission characteristics are analyzed and it is found that prepared glasses possess larger calculated predicted spontaneous transition probability (39.97 s−1), emission cross section σem (10.18 × 10−21 cm2) and σem × Δλeff (945.32 × 10−28 cm3), corresponding to the 2.7 μm emission of Er3+: 4I11/2→ 4I13/2 transition. The results suggest that the prepared glasses might be appropriate optical material for mid-infrared laser application. Moreover, rate equation analysis which is rarely used in bulk glass has been carried out to explain the relationship between emission intensity and Er3+ concentration. The calculation results show that with the increment of Er3+ concentration, the energy transfer up-conversion rate of 4I13/2 state increases while the rate of 4I11/2 state reduces, resulting in the change of 2.7 μm emission. PMID:26032900

  12. Organic solution-processible electroluminescent molecular glasses for non-doped standard red OLEDs with electrically stable chromaticity

    SciTech Connect

    Bi, Xiaoman; Zuo, Weiwei; Liu, Yingliang Zhang, Zhenru; Zeng, Cen; Xu, Shengang; Cao, Shaokui

    2015-10-15

    Highlights: • The D–A–D electroluminescent molecular glasses are synthesized. • Non-doped red electroluminescent film is fabricated by spin-coating. • Red OLED shows stable wavelength, luminous efficiency and chromaticity. • CIE1931 coordinate is in accord with standard red light in PAL system. - Abstract: Organic light-emitting molecular glasses (OEMGs) are synthesized through the introduction of nonplanar donor and branched aliphatic chain into electroluminescent emitters. The target OEMGs are characterized by {sup 1}H NMR, {sup 13}C NMR, IR, UV–vis and fluorescent spectra as well as elemental analysis, TG and DSC. The results indicated that the optical, electrochemical and electroluminescent properties of OEMGs are adjusted successfully by the replacement of electron-donating group. The non-doped OLED device with a standard red electroluminescent emission is achieved by spin-coating the THF solution of OEMG with a triphenylamine moiety. This non-doped red OLED device takes on an electrically stable electroluminescent performance, including the stable maximum electroluminescent wavelength of 640 nm, the stable luminous efficiency of 2.4 cd/A and the stable CIE1931 coordinate of (x, y) = (0.64, 0.35), which is basically in accord with the CIE1931 coordinate (x, y) = (0.64, 0.33) of standard red light in PAL system.

  13. Copper-doped borosilicate bioactive glass scaffolds with improved angiogenic and osteogenic capacity for repairing osseous defects.

    PubMed

    Zhao, Shichang; Wang, Hui; Zhang, Yadong; Huang, Wenhai; Rahaman, Mohamed N; Liu, Zhongtang; Wang, Deping; Zhang, Changqing

    2015-03-01

    There is growing interest in the use of synthetic biomaterials to deliver inorganic ions that are known to stimulate angiogenesis and osteogenesis in vivo. In the present study, we investigated the effects of varying amounts of copper in a bioactive glass on the response of human bone marrow-derived mesenchymal stem cells (hBMSCs) in vitro and on blood vessel formation and bone regeneration in rat calvarial defects in vivo. Porous scaffolds of a borosilicate bioactive glass (composition 6Na2O, 8K2O, 8MgO, 22CaO, 36B2O3, 18SiO2, 2P2O5, mol.%) doped with 0.5, 1.0 and 3.0wt.% CuO were created using a foam replication method. When immersed in simulated body fluid, the scaffolds released Cu ions into the medium and converted to hydroxyapatite. At the concentrations used, the Cu in the glass was not toxic to the hBMSCs cultured on the scaffolds in vitro. The alkaline phosphatase activity of the hBMSCs and the expression levels of angiogenic-related genes (vascular endothelial growth factor and basic fibroblast growth factor) and osteogenic-related genes (runt-related transcription factor 2, bone morphogenetic protein-2 and osteopontin) increased significantly with increasing amount of Cu in the glass. When implanted in rat calvarial defects in vivo, the scaffolds (3wt.% CuO) significantly enhanced both blood vessel formation and bone regeneration in the defects at 8weeks post-implantation. These results show that doping bioactive glass implants with Cu is a promising approach for enhancing angiogenesis and osteogenesis in the healing of osseous defects.

  14. Synthesis and properties of ZnTe and Eu{sup 3+} ion co-doped glass nanocomposites

    SciTech Connect

    Rahaman Molla, Atiar; Tarafder, Anal; Dey, Chirantan; Karmakar, Basudeb

    2014-10-28

    In this study, ZnTe (II-VI) semiconductor and Eu{sup +3}-ion co-doped borosilicate glass has been prepared in the SiO{sub 2}-K{sub 2}O-CaO-BaO-B{sub 2}O{sub 3} glass system followed by controlled heat-treatment to produce glass nanocomposites. Glass transition temperature and crystallization peak temperature have been evaluated using DSC analysis. Dilatometric studies were carried out to evaluate thermal expansion co-efficient, glass transition temperature, and dilatometric softening temperature and found to be 10.7 × 10{sup −6}/K, 580° C and 628° C, respectively. TEM micrographs demonstrate formation of nano sized crystallites of less than 50 nm. The ZnTe crystal formation also established through selected area electron diffraction (SAED) analysis and high resolution images obtained through TEM studies. With increasing heat treatment time, optical transmission cut-off wavelength (λ{sub cut-off}) shifted towards higher wavelength. Excitation spectra were recorded by monitoring emission at 613 nm corresponding to the {sup 5}D{sub 0} → {sup 7}F{sub 2} transition. An intense 394 nm excitation band corresponding to the {sup 7}F{sub 0} → {sup 5}L{sub 6} transition was observed. Emission spectra were then recorded by exciting the glass samples at 394 nm. When the glass is heat-treated for 30 min at 610° C, a 6-fold increase in the intensity of the red emission at 612 nm has been observed, which is attributed to the segregation of Eu{sup 3+} ions into the low phonon energy ZnTe crystallites and as the size of the nanocrystals is smaller than the size of the exciton, quantum confinement effect is visible. Further increase in heat-treatment duration led to decrease in luminescence intensity due to the growth of larger size crystals. {sup 5}D{sub 1} → {sup 7}F{sub 0} transition is visible only in the samples heat-treated for 30 min and 1 h, which is a characteristic of presence of Eu{sup 3+} ions in the low phonon energy ZnTe crystal sites. The

  15. Three-dimensional endothelial cell morphogenesis under controlled ion release from copper-doped phosphate glass.

    PubMed

    Stähli, Christoph; James-Bhasin, Mark; Nazhat, Showan N

    2015-02-28

    Copper ions represent a promising angiogenic agent but are associated with cytotoxicity at elevated concentrations. Phosphate-based glasses (PGs) exhibit adjustable dissolution properties and allow for controlled ion release. This study examined the formation of capillary-like networks by SVEC4-10 endothelial cells (ECs) seeded in a three-dimensional (3D) type I collagen hydrogel matrix mixed with PG particles of the formulation 50P2O5-30CaO-(20-x)Na2O-xCuO (x=0 and 10 mol%). Copper and total phosphorus release decreased over time and was more sustained in the case of 10% CuO PG. Moreover, increasing the concentration of 10% CuO PG in collagen substantially delayed dissolution along with preferential release of copper. A 3D morphometric characterization method based on confocal laser scanning microscopy image stacks was developed in order to quantify EC network length, connectivity and branching. Network length was initially reduced in a concentration-dependent fashion by 10% CuO PG and, to a lesser extent, by 0% CuO PG, but reached values identical to the non-PG control by day 5 in culture. This reduction was attributed to a PG-mediated decrease in cell metabolic activity while cell proliferation as well as network connectivity and branching were independent of PG content. Gene expression of matrix metalloproteinases (MMP)-1 and -2 was up-regulated by PGs, indicating that MMPs did not play a critical role in network growth. The relationship between ion release and EC morphogenesis in 3D provided in this study is expected to contribute to an ultimately successful pro-angiogenic application of CuO-doped PGs. PMID:25575746

  16. Modeling of cluster organization in metal-doped oxide glasses irradiated by a train of femtosecond laser pulses

    NASA Astrophysics Data System (ADS)

    Smetanina, Evgeniya; Chimier, Benoit; Petit, Yannick; Varkentina, Nadezda; Fargin, Evelyne; Hirsch, Lionel; Cardinal, Thierry; Canioni, Lionel; Duchateau, Guillaume

    2016-01-01

    The formation of silver cluster structures at submicrometer spatial scales under the irradiation by high-power femtosecond laser pulses with high repetition rate was observed in various glasses containing silver ions. In order to account for the formation of these structures in metal-doped glasses, we present a theoretical model for the organization of noble metallic clusters induced by a train of femtosecond laser pulses. The model includes photoionization and laser heating of the sample, diffusion, kinetic reactions, and dissociation of metallic species. This model was applied to reproduce the formation of cluster structures in silver-doped phosphate glass. The parameters of the silver structures were obtained numerically under various incident pulse intensities and number of pulses. Numerical modeling shows that the involved microscopic physical and chemical processes naturally lead to the emergence of a silver cluster organization, together with charge migration and subsequent trapping giving rise to a strong static electric field buried in the irradiated area as experimentally observed. Based on this modeling, a theoretical basis is provided for the design of new metallic cluster structures with nanoscale size.

  17. Luminescence studies on Dy3+ and Dy3+:Eu3+ co-doped boro-phosphate glasses for WLED applications

    NASA Astrophysics Data System (ADS)

    Vijayakumar, M.; Uma, V.; Arunkumar, S.; Marimuthu, K.

    2015-06-01

    Dy3+ and Dy3+:Eu3+ co-doped boro-phosphate glasses have been prepared and optically characterized using absorption, luminescence and decay measurements. The Nephelauxetic ratios (β), Bonding parameters (δ) and Judd-Ofelt (JO) intensity parameters Ωλ (λ = 2, 4 and 6) were calculated to study the nature of the environment around the RE3+ ions in the prepared glasses. The yellow to blue (Y/B) intensity ratio and the chromaticity color coordinates were calculated from the luminescence measurements. The lifetimes of the 4F9/2 excited level were measured using decay curves and is found to decrease in the Dy3+:Eu3+ co-doped glass due to the occurrence of resonant energy transfer between Dy3+-Eu3+ ions and the non-exponential decay rates have been fitted with Inokuti-Hirayama (IH) model. The decay curves are well fitted for S= 6 suggesting that the interaction between active ions for the energy transfer is of dipole-dipole nature.

  18. Absorption and photoluminescence properties of Er-doped and Er/Yb codoped soda-silicate laser glasses

    SciTech Connect

    Li, S.F.; Zhang, Q.Y.; Lee, Y.P.

    2004-11-01

    Er-doped and Er/Yb codoped soda-silicate laser glasses with various concentrations of Er and Yb were fabricated. The absorption and the photoluminescence (PL) spectra were measured and analyzed. For the Er- doped soda-slilicate glasses, the optimum Er concentration for the PL intensity at 1536 nm turns out to be 0.5 at. %, and the full width at half maximum (FWHM) of PL spectrum increases from 18 to 26 nm, with the increase of the concentration from 0.1 to 0.8 at. %. The PL intensity of Er/Yb codoped soda-silicate glasses with an Er concentration of 0.5 at. % is enhanced approximately by four times, and the optimum Yb concentration for the PL intensity at 1536 nm is analyzed to be 3.0 at. %. The PL spectrum becomes broader with increasing the Yb concentration, up to a FWHM of 80 nm at 6.0 at. %. Yb. The relation between the absorption and PL spectra, together with the mechanism of PL broadening, has also been addressed.

  19. Yb-doped silica-based laser fibers: correlation of photodarkening kinetics and related optical properties with the glass composition

    NASA Astrophysics Data System (ADS)

    Kirchhof, J.; Unger, S.; Jetschke, S.; Schwuchow, A.; Leich, M.; Reichel, V.

    2009-02-01

    In the last years, photodarkening in ytterbium doped silica based laser fibers turned out to be a critical factor for high power laser action. Several investigations have been carried out in order to characterize the time dependent increase of the fiber loss and to understand and model the complex optical phenomenon. Despite of progress in this field, there is still a lack of data concerning the detailed influence of fiber composition and preparation process parameters as well as concerning the role of atomic defects in the core glass. Here we report on investigations about the photodarkening in dependence on the glass composition of the fiber laser core. By MCVD, fibers with different codopants (additional to the active ytterbium doping) have been prepared in a well-defined manner, regarding process parameters and glass composition, and comprehensively characterized. In addition to the photodarkening measurements, further optical properties have been measured on the fibers and fiber performs, which are related to the photodarkening effect: intensity and spectral behaviour of the Yb3+ absorption and emission in the NIR, cooperative visible fluorescence, UV absorption and UV excited visible emission. The concentration of codopants which are commonly used for active and passive lightguide fibers (aluminium, germanium, phosphorus) was systematically varied and correlated with the optical properties.

  20. Er 3+ - Yb 3+ co-doped phosphate glass optical fiber for application at 1.54 microns

    NASA Astrophysics Data System (ADS)

    Lafond, Christophe; Osouf, Jocelyne; Laperle, Pierre; Soucy, Jean-Luc; Desrosiers, Cynthia; Morency, Steeve; Croteau, André; Parent, André

    2006-09-01

    We present current work developed at INO on phosphate glass optical fiber for laser and amplifier applications at 1.54 microns. Core and cladding glasses were fabricated by a multi-components melting process which gave an uniform refractive index core profile. Rod-in-tube method under Argon atmosphere was used to fabricate optical fibers. The effect of nitrogen atmosphere on hydroxyl groups OH - during glass melting was studied. The absorption coefficient calculated at 3.42 μm was found to be lower than 0.5 cm -1 which corresponds to less than 70 ppm OH -. Absorption and emission cross sections were calculated at 1534 nm. Fabrication process allowed us to decrease background losses of core Er 3+ - Yb 3+ co-doped fiber between 0.02 and 0.04 dB/cm. Laser power was measured at 1563 nm and a 26% slope efficiency was achieved with a 22 cm-long single-clad fiber co-doped with 1.1 wt% in Er 3+ and 11.1 wt% in Yb 3+. For the same fiber, an internal gain was found to be 20 dB at 1536 nm for a 5-cm-long fiber.

  1. Enhanced NIR downconversion luminescence by precipitating nano Ca5(PO4)3F crystals in Eu2+-Yb3+ co-doped glass.

    PubMed

    Li, Chen; Song, Zhiguo; Li, Yongjin; Lou, Kai; Qiu, Jianbei; Yang, Zhengwen; Yin, Zhaoyi; Wang, Xue; Wang, Qi; Wan, Ronghua

    2013-10-01

    Eu(2+)-Yb(3+) co-doped transparent glass-ceramic containing nano-Ca5(PO4)3F (FAP) was prepared in reducing atmosphere. XRD and TEM analysis indicated that nano-FAP about 40 nm precipitated homogeneously in glass matrix after heat treatment. Confirmed by spectroscopy measurements, the crystal-like absorption and emission of Eu(2+) indicated the partition of Eu(2+) into FAP nanocrystals in glass ceramic. NIR emission due to the transition (2)F5/2→(2)F7/2 of Yb(3+) ions (about 980-1100 nm) was observed from glasses under ultraviolet excitation, ascribed to downconversion from Eu(2+) to Yb(3+), which can be enhanced by precipitating nano-FAP crystals. The results indicated that Eu(2+)-Yb(3+) co-doped glass-ceramic embedding with nano-FAP is a promising candidate as downconversion materials for enhancing conversion efficiency of solar cells.

  2. Visible to near-infrared down-shifting in Tm3+ doped fluoride glasses for solar cells efficiency enhancement

    NASA Astrophysics Data System (ADS)

    Maalej, Olfa; Merigeon, Julien; Boulard, Brigitte; Girtan, Mihaela

    2016-10-01

    In this paper, down-conversion of Tm3+ doped fluoride ZLAG glasses with composition of 70.2ZrF4-(23.4-x)LaF3-0.6AlF3-5.8GaF3-xTmF3 (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 Tm3+ 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 Tm3+ doping concentrations up to 1 mol% Tm3+. Further increase of the Tm3+ concentration leads to a decrease of solar cell conversion efficiency as a result of concentration quenching.

  3. Synthesis of Sm{sup 3+}-doped strontium barium niobate crystals in glass by samarium atom heat processing

    SciTech Connect

    Chayapiwut, Nakorn; Honma, Tsuyoshi; Benino, Yasuhiko; Fujiwara, Takumi; Komatsu, Takayuki . E-mail: komatsu@chem.nagaokaut.ac.jp

    2005-11-15

    New glasses giving the crystallization of Sm{sup 3+}-doped Sr {sub x} Ba{sub 1-} {sub x} Nb{sub 2}O{sub 6} (SBN) ferroelectrics have been developed in the Sm{sub 2}O{sub 3}-SrO-BaO-Nb{sub 2}O{sub 5}-B{sub 2}O{sub 3} system, and the formation of SBN crystal dots and lines by continuous wave Nd:YAG laser (wavelength:1064 nm, power: 1 W) irradiations, i.e., samarium atom heat processing, has been examined. The formation of Sm{sup 3+}-doped SBN non-linear optical crystals is confirmed from X-ray diffraction analyses, micro-Raman scattering spectra, second harmonic generations, and photoluminescence spectra. Sm{sup 3+}-doped SBN crystal dots with the diameters of 20-70 {mu}m and lines with the widths of 20-40 {mu}m are written at the surface of some glasses such as 10Sm{sub 2}O{sub 3}.10SrO.10BaO.20Nb{sub 2}O{sub 5}.50B{sub 2}O{sub 3} (mol%) by Nd:YAG laser irradiations with the irradiation times of 20-70 s for the dots and with the scanning speeds of 1-5 {mu}m/s for the lines. The present study suggests that the samarium atom heat processing has a potential for the patterning of optical waveguides consisting of ferroelectric SBN crystals in glass substrates.

  4. Osteoblastic differentiation under controlled bioactive ion release by silica and titania doped sodium-free calcium phosphate-based glass.

    PubMed

    Shah Mohammadi, Maziar; Chicatun, Florencia; Stähli, Christoph; Muja, Naser; Bureau, Martin N; Nazhat, Showan N

    2014-09-01

    Sodium-free phosphate-based glasses (PGs) doped with both SiO2 and TiO2 (50P2O5-40CaO-xSiO2-(10-x)TiO2, where x=10, 7, 5, 3, and 0mol%) were developed and characterised for controlled ion release applications in bone tissue engineering. Substituting SiO2 with TiO2 directly increased PG density and glass transition temperature, indicating a cross-linking effect of Ti on the glass network which was reflected by significantly reduced degradation rates in an aqueous environment. X-ray diffraction confirmed the presence of Ti(P2O7) in crystallised TiO2-containing PGs, and nuclear magnetic resonance showed an increase in Q(1) phosphate species with increasing TiO2 content. Substitution of SiO2 with TiO2 also reduced hydrophilicity and surface energy. In biological assays, MC3T3-E1 pre-osteoblasts effectively adhered to the surface of PG discs and the incorporation of TiO2, and hence higher stability of the PG network, significantly increased cell viability and metabolic activity indicating the biocompatibility of the PGs. Addition of SiO2 increased ionic release from the PG, which stimulated alkaline phosphatase (ALP) activity in MC3T3-E1 cells upon ion exposure. The incorporation of 3mol% TiO2 was required to stabilise the PG network against unfavourable rapid degradation in aqueous environments. However, ALP activity was greatest in PGs doped with 5-7mol% SiO2 due to up-regulation of ionic concentrations. Thus, the properties of PGs can be readily controlled by modifying the extent of Si and Ti doping in order to optimise ion release and osteoblastic differentiation for bone tissue engineering applications. PMID:24945606

  5. Resonant excited state absorption and relaxation mechanisms in Tb3+-doped calcium aluminosilicate glasses: an investigation by thermal mirror spectroscopy.

    PubMed

    Bianchi, G S; Zanuto, V S; Astrath, F B G; Malacarne, L C; Terra, I A A; Catunda, T; Nunes, L A O; Jacinto, C; Andrade, L H C; Lima, S M; Baesso, M L; Astrath, N G C

    2013-11-15

    Resonant excited state absorption (ESA) and relaxation processes in Tb(3+)-doped aluminosilicate glasses are quantitatively evaluated. A model describing the excitation steps and upconversion emission is developed and applied to interpret the results from laser-induced surface deformation using thermal mirror spectroscopy. The fluorescence quantum efficiency of level (5)D(4) was found to be close to unity and concentration independent while, for the level (5)D(3), it decreases with Tb(3+) concentration. Emission spectroscopy measurements supported these results. ESA cross sections are found to be more than three orders of magnitude higher than the ground state absorption cross section. PMID:24322101

  6. Silver nanoparticles enhanced luminescence properties of Er³⁺ doped tellurite glasses: Effect of heat treatment

    SciTech Connect

    Fares, Hssen; Férid, Mokhtar; Elhouichet, Habib; Gelloz, Bernard

    2014-09-28

    Tellurite glasses doped Er³⁺ ions and containing Silver nanoparticles (Ag NPs) are prepared using melt quenching technique. The nucleation and growth of Ag NPs were controlled by a thermal annealing process. The X-ray diffraction pattern shows no sharp peak indicating an amorphous nature of the glasses. The presence of Ag NPs is confirmed from transmission electron microscopy micrograph. Absorption spectra show typical surface plasmon resonance (SPR) band of Ag NPs within the 510–550 nm range in addition to the distinctive absorption peaks of Er³⁺ ions. The Judd-Ofelt (J-O) intensity parameters, oscillator strengths, spontaneous transition probabilities, branching ratios, and radiative lifetimes were successfully calculated based on the experimental absorption spectrum and the J-O theory. It was found that the presence of silver NPs nucleated and grown during the heat annealing process improves both of the photoluminescence (PL) intensity and the PL lifetime relative to the ⁴I13/2 → ⁴I15/2 transition. Optimum PL enhancement was obtained after 10 h of heat-treatment. Such enhancements are mainly attributed to the strong local electric field induced by SPR of silver NPs and also to energy transfer from the surface of silver NPs to Er³⁺ ions, whereas the quenching is ascribed to the energy transfer from Er³⁺ ions to silver NPs. Using the Mc Cumber method, absorption cross-section, calculated emission cross-section, and gain cross-section for the ⁴I13/2 → ⁴I15/2 transition were determined and compared for the doped and co-doped glasses. The present results indicate that the glass heat-treated for 10 h has good prospect as a gain medium applied for 1.53 μm band broad and high-gain erbium-doped fiber amplifiers.

  7. Large-mode-area single-mode-output Neodymium-doped silicate glass all-solid photonic crystal fiber.

    PubMed

    Li, Wentao; Chen, Danping; Qinling, Zhou; Hu, Lili

    2015-07-24

    We have demonstrated a 45 μm core diameter Neodymium-doped all-solid silicate glass photonic crystal fiber laser with a single mode laser output. The structure parameters and modes information of the fiber are both demonstrated by theoretical calculations using Finite Difference Time Domain (FDTD) method and experimental measurements. Maximum 0.8 W output power limited by launched pump power has been generated in 1064 nm with laser beam quality factor M(2) 1.18.

  8. Large-mode-area single-mode-output Neodymium-doped silicate glass all-solid photonic crystal fiber

    PubMed Central

    Li, Wentao; Chen, Danping; Qinling, Zhou; Hu, Lili

    2015-01-01

    We have demonstrated a 45 μm core diameter Neodymium-doped all-solid silicate glass photonic crystal fiber laser with a single mode laser output. The structure parameters and modes information of the fiber are both demonstrated by theoretical calculations using Finite Difference Time Domain (FDTD) method and experimental measurements. Maximum 0.8 W output power limited by launched pump power has been generated in 1064 nm with laser beam quality factor M2 1.18. PMID:26205850

  9. Three-photon near-infrared quantum cutting in Tm{sup 3+}-doped transparent oxyfluoride glass ceramics

    SciTech Connect

    Yu, D. C.; Zhang, J. P.; Chen, Q. J.; Zhang, W. J.; Yang, Z. M.; Zhang, Q. Y.

    2012-10-22

    Efficient three-step sequential three-photon near-infrared (NIR) quantum cutting in Tm{sup 3+}-doped transparent oxyfluoride glass ceramics has been demonstrated, where an absorbed blue photon could be cut into three NIR photons at 1190, 1460, and 1800 nm with quantum yield greater than unity. On the basis of static and dynamic photoemission, monitored excitation, and time-resolved fluorescence spectra, we investigate in detail the underlying optoelectronic mechanism. Further development of an efficient triply-cutting material might open up a path towards ultra-efficient photonic devices, which enables more photons emitted than absorbed in the excitation process.

  10. Application of glass particles doped by Zn(+2) as an antimicrobial and atoxic compound in LLDPE and HDPE.

    PubMed

    Santos, M F; Machado, C; Tachinski, C G; Júnior, J F; Piletti, R; Peterson, M; Fiori, M A

    2014-06-01

    This study demonstrates the potential application of glass particles doped with Zn(+2) (GZn) as an atoxic, antimicrobial additive when used in conjunction with high density polyethylene (HDPE) and linear low density polyethylene (LLDPE) polymers. Toxicity tests demonstrated that these modified glass particles were nontoxic to human cells, and atomic absorption analyses demonstrated the migration of ionic species in quantities less than 2.0ppm for both the HDPE/GZn and LLDPE/GZn compounds. Microbiological tests demonstrated the antimicrobial effect of the pure GZn compound as well as the polymeric HDPE/GZn and LLDPE/GZn compounds. In addition, at percentages of GZn higher than 2.00wt.% and at a time of 4h, the bactericidal performance is excellent and equal for both polymeric compounds. PMID:24863241

  11. Slab optical waveguides in Er3 +-doped tellurite glass by N+ ion implantation at 1.5 MeV

    NASA Astrophysics Data System (ADS)

    Berneschi, Simone; Brenci, Massimo; Nunzi Conti, Gualtiero; Pelli, Stefano; Bettinelli, Marco; Speghini, Adolfo; Bányász, Istvan; Fried, Miklós; Khanh, Nguyen Q.; Lohner, Tivadar; Petrik, Péter; Watterich, Andrea; Zolnai, Zsolt

    2011-07-01

    Slab optical waveguides were fabricated in tung-sten-tellurite glass doped with Er3 + ions by means of nitrogen ion implantation at 1.5 MeV. A wide range of ion doses (from 5.1012 to 8.1016 ions/cm2) was used. Optical characterization, performed by dark-line spectroscopy, revealed that the waveguides were of optical barrier type: the implanted layer exhibited a decrease of the refractive index with respect to the virgin bulk glass, while the region comprised between the sample surface and the end of the ion track acted as an optical guiding structure. It was also demonstrated that a post-implantation annealing process, performed at various temperatures on the samples implanted at higher doses, contributes to the reduction of the barrier region.

  12. Sustained phase separation and spin glass in Co-doped KxFe2 -ySe2 single crystals

    NASA Astrophysics Data System (ADS)

    Ryu, Hyejin; Wang, Kefeng; Opacic, M.; Lazarevic, N.; Warren, J. B.; Popovic, Z. V.; Bozin, Emil S.; Petrovic, C.

    2015-11-01

    We present Co substitution effects in KxFe2 -y -zCozSe2 (0.06 ≤z ≤1.73 ) single-crystal alloys. By 3.5% of Co doping superconductivity is suppressed, whereas phase separation of semiconducting K2Fe4Se5 and superconducting/metallic KxFe2Se2 is still present. We show that the arrangement and distribution of the superconducting phase (stripe phase) are connected with the arrangement of K, Fe, and Co atoms. Semiconducting spin glass is found in proximity to the superconducting state, persisting for large Co concentrations. At high Co concentrations a ferromagnetic metallic state emerges above the spin glass. This is coincident with changes of the unit cell and arrangement and connectivity of the stripe conducting phase.

  13. Sustained phase separation and spin glass in Co-doped KxFe2-ySe2 single crystals

    DOE PAGESBeta

    Ryu, Hyejin; Wang, Kefeng; Opacic, M.; Lazarevic, N.; Warren, J. B.; Popovic, Z. V.; Bozin, Emil S.; Petrovic, C.

    2015-11-19

    We describe Co substitution effects in KxFe2-y-zCozSe2 (0.06 ≤ z ≤ 1.73) single crystal alloys. By 3.5% of Co doping superconductivity is suppressed whereas phase separation of semiconducting K2Fe4Se5 and superconducting/metallic KxFe2Se2 is still present. We show that the arrangement and distribution of superconducting phase (stripe phase) is connected with the arrangement of K, Fe and Co atoms. Semiconducting spin glass is found in proximity to superconducting state, persisting for large Co concentrations. At high Co concentrations ferromagnetic metallic state emerges above the spin glass. This is coincident with changes of the unit cell, arrangement and connectivity of stripemore » conducting phase.« less

  14. Laser-induced radial birefringence and spin-to-orbital optical angular momentum conversion in silver-doped glasses

    SciTech Connect

    Amjad, Jafar Mostafavi; Khalesifard, Hamid Reza; Slussarenko, Sergei; Karimi, Ebrahim; Santamato, Enrico; Marrucci, Lorenzo

    2011-07-04

    Samples of Ag{sup +}/Na{sup +} ion-exchanged glass that have been subject to intense laser irradiation may develop novel optical properties, as a consequence of the formation of patterns of silver nanoparticles and other structures. Here, we report the observation of a laser-induced permanent transverse birefringence, with the optical axis forming a radial pattern, as revealed by the spin-to-orbital angular momentum conversion occurring in a probe light beam. The birefringence pattern can be modeled well as resulting from thermally-induced stresses arising in the silver-doped glass during laser exposure, although the actual mechanism leading to the permanent anisotropy is probably more complex.

  15. Effect of natural Fe3O4 nanoparticles on structural and optical properties of Er3+ doped tellurite glass

    NASA Astrophysics Data System (ADS)

    Widanarto, W.; Sahar, M. R.; Ghoshal, S. K.; Arifin, R.; Rohani, M. S.; Hamzah, K.

    2013-01-01

    Control doping of magnetic nanoparticles and its influence on optical and structural properties of tellurite glass is important from device perspectives. Natural Fe3O4 nanoparticles obtained by extracting and ball milling iron sand, are incorporated in the Er3+ doped tellurite glasses having composition (80-x)TeO2·xFe3O4·18ZnO·1Li2O·1Er2O3 (0≤x≤1.5) in mol% by melt quenching method at 850 °C. X-Ray diffraction spectra confirms the presence of iron nanoparticles with estimated sizes 18-70 nm and an amorphous structure of the samples. Thermal and optical characterizations are made using diffential thermal analysis, ultraviolet-visible and photoluminescence spectrocopies. It is found that the presence of nanoparticles changes color and thermal stability of the glasses, which is proved by increasing thermal stability factor from 118 to 132 °C. Absorption spectra consist of six peaks corresponding to different transition from ground state to the excited states in which the quench of the peak associated with 4F1/2 is attributed to the effect nanoparticles. Moreover, the shift in the absorption edge from ∼400 to ∼500 nm indicates a significant decrease of the optical energy band gap for both direct and indirect allowed transitions and a decrease in the Urbach energy as much as 0.116 eV is observed. The room temperature down-conversion luminescence spectra obtained under 500 nm excitation exhibit two strong peaks related to excited states 4S3/2 and 4F9/2 of Er3+ ions in the absence of nanoparticles. Furthermore, embedding nanoparticles into the glass not only make the peaks weaker but the second peak completely disappears. Interestingly, the emission bands of the Er3+ ion are quenched as concentration of the magnetic nanoparticles is increased.

  16. Structural and luminescence studies of Ho{sup 3+}-doped zinc-aluminium-sodium-phosphate (ZANP) glasses

    SciTech Connect

    Brahmachary, K.; Rajesh, D.; Ratnakaram, Y. C.

    2015-06-24

    Trivalent holmium doped zinc-aluminium-sodium-phosphate (ZANP) glasses were prepared by conventional melt-quenching technique and characterized for their structural and luminescence properties. The amorphous nature, elemental analysis and thermal stability of the glasses were studied by using X-ray diffraction, energy dispersive spectrum and differential scanning calorimetry analysis, respectively. The absorption and fluorescence spectra have been recorded at room temperature. Based on the absorption spectra, the Judd-Ofelt parameters and radiative parameters such as spontaneous transition probabilities (A{sub R}), branching ratios (β{sub R}), radiative lifetimes (τ{sub R}) were calculated and discussed. From the emission spectra emission peak positions (λ{sub P}), effective bandwidths (Δλ{sub eff}) and stimulated emission cross-sections (σ{sub P}) were calculated for the observed emission transitions,{sup 5}S{sub 2} ({sup 5}F{sub 4}→{sup 5}I{sub 8}) and {sup 5}F{sub 5}→{sup 5}I{sub 8} in all the glass samples. The stimulated emission cross-section is higher for ZANPHo10 glass matrix and so it may be useful for laser excitation.

  17. Magnetocaloric effect in heavy rare-earth elements doped Fe-based bulk metallic glasses with tunable Curie temperature

    SciTech Connect

    Li, Jiawei; Huo, Juntao; Chang, Chuntao E-mail: dujun@nimte.ac.cn; Du, Juan E-mail: dujun@nimte.ac.cn; Man, Qikui; Wang, Xinmin; Li, Run-Wei; Law, Jiayan

    2014-08-14

    The effects of heavy rare earth (RE) additions on the Curie temperature (T{sub C}) and magnetocaloric effect of the Fe-RE-B-Nb (RE = Gd, Dy and Ho) bulk metallic glasses were studied. The type of dopping RE element and its concentration can easily tune T{sub C} in a large temperature range of 120 K without significantly decreasing the magnetic entropy change (ΔS{sub M}) and refrigerant capacity (RC) of the alloys. The observed values of ΔS{sub M} and RC of these alloys compare favorably with those of recently reported Fe-based metallic glasses with enhanced RC compared to Gd{sub 5}Ge{sub 1.9}Si{sub 2}Fe{sub 0.1}. The tunable T{sub C} and large glass-forming ability of these RE doped Fe-based bulk metallic glasses can be used in a wide temperature range with the final required shapes.

  18. Luminescence quenching versus enhancement in WO3-NaPO3 glasses doped with trivalent rare earth ions and containing silver nanoparticles

    NASA Astrophysics Data System (ADS)

    Dousti, M. Reza; Poirier, Gael Y.; Amjad, Raja J.; de Camargo, Andrea S. S.

    2016-10-01

    We report on the influence of silver nanoparticles (NPs) on the luminescence behavior of trivalent rare earth (RE) ion doped tungsten-phosphate glasses. In order to induce the growth of NPs, the as-prepared glass samples containing silver atoms, are exposed to heat-treatment above the glass transition temperature. The surface plasmon resonance band of the Ag NPs is observed in the visible range around 420 and 537 nm in the glasses with low and high tungsten content, respectively. Such difference in spectral shift of the plasmon band is attributed to the difference in the refractive index of the two studied glass compositions. Heat-treatment results in the general increase in number of NPs, while in the case of glasses with low tungsten content, it also imposes a shift to the Ag plasmon band. The NPs size distribution (4-10 nm) was determined in good agreement with the values obtained by using Mie theory and by transmission electron microscopy. The observed quenching in the visible luminescence of glasses doped with Eu3+, Tb3+ or Er3+is attributed to energy transfer from the RE ions to Ag species, while an enhanced near-infrared emission in Er3+ doped glasses is discussed in terms of the chemical contribution of silver, rather than the most commonly claimed enhancement of localized field or energy transfer from silver species to Er3+. The results are supported by the lifetime measurements. We believe that this study gives further insight and in-depth exploration of the somewhat controversial discussions on the influence of metallic NPs plasmonic effects in RE-doped glasses.

  19. Influence of mixed alkali on the spectral properties of vanadyl ions doped xNa{sub 2}O-(30 - x)K{sub 2}O-60B{sub 2}O{sub 3} glasses-an EPR and optical study

    SciTech Connect

    Sreekanth Chakradhar, R.P. . E-mail: chakra72@physics.iisc.ernet.in; Ramesh, K.P.; Rao, J.L.; Ramakrishna, J.

    2005-06-15

    Electron paramagnetic resonance (EPR) and optical investigations have been performed in the mixed alkali borate xNa{sub 2}O-(30 - x)K{sub 2}O-60B{sub 2}O{sub 3} (5 {<=} x {<=} 25) glasses doped with 10 mol% of vanadyl ions in order to look for the effect of 'mixed alkalis' on the spectral properties of the glasses. The observed EPR spectra have structures for x > 5 mol% which are characteristic of a hyperfine interaction arising from an unpaired electron with the {sup 51}V nucleus and it builds up in intensity as x increases. It is observed that the mixed alkali play a significant role in accommodating the vanadyl ions in these mixed alkali glasses and for x > 5 mol%, shows a well resolved hyperfine structure typical for isolated VO{sup 2+} ions. The spin-Hamiltonian parameters (g and A), the dipolar hyperfine coupling parameter (P) and Fermi contact interaction parameter (k) have been evaluated. It is observed that the spin-Hamiltonian parameters do not vary much with the change in composition. It is observed that with increase of x, an increase occurs in tetragonal distortion for VO{sup 2+}. The number of spins (N) participating in resonance and the paramagnetic susceptibility ({chi}) have been calculated. It is observed that N and {chi} increase with x. The optical bandgap energies evaluated for these glasses slightly increase with x and reach a maximum around x = 20 and thereafter decrease showing the mixed alkali effect. Optical band gap energies obtained in the present work vary from 2.73 to 3.10 eV for both the direct and indirect transitions. The physical parameters of the glasses are also determined with respect to the composition.

  20. Structure of AgI-doped Ge-In-S glasses: Experiment, reverse Monte Carlo modelling, and density functional calculations

    SciTech Connect

    Chrissanthopoulos, A.; Jovari, P.; Kaban, I.; Gruner, S.; Kavetskyy, T.; Borc, J.; Wang, W.; Ren, J.; Chen, G.; Yannopoulos, S.N.

    2012-08-15

    We report an investigation of the structure and vibrational modes of Ge-In-S-AgI bulk glasses using X-ray diffraction, EXAFS spectroscopy, Reverse Monte-Carlo (RMC) modelling, Raman spectroscopy, and density functional theoretical (DFT) calculations. The combination of these techniques made it possible to elucidate the short- and medium-range structural order of these glasses. Data interpretation revealed that the AgI-free glass structure is composed of a network where GeS{sub 4/2} tetrahedra are linked with trigonal InS{sub 3/2} units; S{sub 3/2}Ge-GeS{sub 3/2} ethane-like species linked with InS{sub 4/2}{sup -} tetrahedra form sub-structures which are dispersed in the network structure. The addition of AgI into the Ge-In-S glassy matrix causes appreciable structural changes, enriching the Indium species with Iodine terminal atoms. The existence of trigonal species InS{sub 2/2}I and tetrahedral units InS{sub 3/2}I{sup -} and InS{sub 2/2}I{sub 2}{sup -} is compatible with the EXAFS and RMC analysis. Their vibrational properties (harmonic frequencies and Raman activities) calculated by DFT are in very good agreement with the experimental values determined by Raman spectroscopy. - Graphical abstract: Experiment (XRD, EXAFS, RMC, Raman scattering) and density functional calculations are employed to study the structure of AgI-doped Ge-In-S glasses. The role of mixed structural units as illustrated in the figure is elucidated. Highlights: Black-Right-Pointing-Pointer Doping Ge-In-S glasses with AgI causes significant changes in glass structure. Black-Right-Pointing-Pointer Experiment and DFT are combined to elucidate short- and medium-range structural order. Black-Right-Pointing-Pointer Indium atoms form both (InS{sub 4/2}){sup -} tetrahedra and InS{sub 3/2} planar triangles. Black-Right-Pointing-Pointer (InS{sub 4/2}){sup -} tetrahedra bond to (S{sub 3/2}Ge-GeS{sub 3/2}){sup 2+} ethane-like units forming neutral sub-structures. Black-Right-Pointing-Pointer Mixed

  1. Visible up-conversion and near-infrared luminescence of Er3+/Yb3+ co-doped SbPO4-GeO2 glasses

    NASA Astrophysics Data System (ADS)

    Manzani, D.; Montesso, M.; Mathias, C. F.; Krishanaiah, K. Venkata; Ribeiro, S. J. L.; Nalin, M.

    2016-07-01

    Recent advances in glass chemistry have led to new multifunctional optical glasses of great technological importance. Glasses containing high amounts of antimony have been studied for use in nonlinear optics, near-infrared transmission, and as hosts for rare-earth ions in photonic devices. This work describes a luminescence study of Er3+ and Er3+/Yb3+ co-doping in a new SbPO4-GeO2 binary glass system. Near-infrared and visible up-conversion emissions were observed in the green and red regions, which are enhanced when the samples are co-doped with Yb3+. Near-infrared emissions have good quantum efficiency and full width half maximum of 61 nm. Visible up-conversion emissions are governed by two photons and described by excited state absorption, energy transfer and cross-relaxation processes.

  2. Thermal lens study of thermo-optical properties and concentration quenching of Er{sup 3+}-doped lead pyrophosphate-based glasses

    SciTech Connect

    Santos, C. C.; Rocha, U.; Vermelho, M. V. D.; Jacinto, C.; Guedes, I.; Boatner, L. A.

    2012-06-15

    In this work, we have used the thermal lens technique combined with conventional spectroscopy to characterize the thermo-optical properties of Er{sup 3+}-doped lead pyrophosphate-based glasses. More precisely, we have investigated and quantified experimentally the fluorescence quantum efficiencies of the Er{sup 3+} levels, and we describe the role of concentration quenching effects. The fluorescence quantum efficiency of the {sup 4}I{sub 13/2} level is very high when compared to other phosphate glasses, while that of the green-coupled levels is very small. Other important photonic materials parameters, such as the thermal diffusivity and temperature coefficient of the optical path length change, were obtained and compared with those of other glass systems. The cumulative results obtained here for the Er-doped lead pyrophosphate glass show that this material is a good candidate for photonic applications with a characteristic Er{sup 3+} infrared emission around 1550 nm.

  3. Local structure characterization and thermal properties of P2O5sbnd MgOsbnd Na2Osbnd Li2O glasses doped with SiO2

    NASA Astrophysics Data System (ADS)

    Wu, Fengnian; Li, Sheng; Chang, Ziyuan; Liu, Hongting; Huang, Sanxi; Yue, Yunlong

    2016-08-01

    Pure and SiO2 doped P2O5sbnd MgOsbnd Na2Osbnd Li2O glass has been prepared by the traditional melt quenching and heat treatment techniques. Via X-ray diffraction (XRD) patterns, all the samples are proved to be amorphous. Field emission scanning electron microscopy (FESEM) and macroscopic observation show that all the samples are homogeneous glasses and no phase splitting phenomenon. Fourier transform infrared (FTIR) spectrum shows that the amount of non-bridging oxygen decreases and the polymerization degree of the glass network structure increases after introducing SiO2 into glasses. Meanwhile, density and molar volume gradually decline with the increasing of SiO2. The glass transition (Tg) and the first crystallization temperature (Tc) indicates thermal stability increases in SiO2 added glasses.

  4. Broadband near-infrared emission from Tm{sup 3+}/Er{sup 3+} co-doped nanostructured glass ceramics

    SciTech Connect

    Chen Daqin; Wang Yuansheng; Bao Feng; Yu Yunlong

    2007-06-01

    Transparent SiO{sub 2}-Al{sub 2}O{sub 3}-NaF-YF{sub 3} glass ceramics co-doped with Er{sup 3+} and Tm{sup 3+} were prepared by melt quenching and subsequent heating. X-ray diffraction and transmission electron microscopy experiments revealed that {beta}-YF{sub 3} nanocrystals incorporated with Er{sup 3+} and Tm{sup 3+} were precipitated homogeneously among the oxide glass matrix. An integrated broad near-infrared emission band in the wavelength region of 1300-1700 nm, consisting of Tm{sup 3+} emissions around 1472 nm ({sup 3}H{sub 4}{yields}{sup 3}F{sub 4}) and 1626 nm ({sup 3}F{sub 4}{yields}{sup 3}H{sub 6}), and Er{sup 3+} emission around 1543 nm ({sup 4}I{sub 13/2}{yields}{sup 4}I{sub 15/2}), was obtained under 792 nm laser excitation. The full width at half maximum of this integrated band increased with the increasing of [Tm]/[Er] ratio, and it reached as large as 175 nm for the 0.1 mol% Er{sup 3+} and 0.8 mol% Tm{sup 3+} co-doped sample. The energy transfers between Er{sup 3+} and Tm{sup 3+} were proposed to play an important role in tailoring the emission bandwidth of the sample.

  5. TiO2-doped phosphate glass microcarriers: A stable bioactive substrate for expansion of adherent mammalian cells

    PubMed Central

    Guedes, Joana C; Park, Jeong-Hui; Lakhkar, Nilay J; Kim, Hae-Won; Knowles, Jonathan C

    2013-01-01

    Scalable expansion of cells for regenerative cell therapy or to produce large quantities for high-throughput screening remains a challenge for bioprocess engineers. Laboratory scale cell expansion using t-flasks requires frequent passaging that exposes cells to many poorly defined bioprocess forces that can cause damage or alter their phenotype. Microcarriers offer a potential solution to scalable production, lending themselves to cell culture processes more akin to fermentation, removing the need for frequent passaging throughout the expansion period. One main problem with microcarrier expansion, however, is the difficulty in harvesting cells at the end of the process. Therefore, therapies that rely on cell delivery using biomaterial scaffolds could benefit from a microcarrier expansion system whereby the cells and microcarriers are transplanted together. In the current study, we used bioactive glass microcarriers doped with 5% TiO2 that display a controlled rate of degradation and conducted experiments to assess biocompatibility and growth of primary fibroblast cells as a model for cell therapy products. We found that the microcarriers are highly biocompatible and facilitate cell growth in a gradual controlled manner. Therefore, even without additional biofunctionalization methods, Ti-doped bioactive glass microcarriers offer potential as a cell expansion platform. PMID:22935537

  6. Properties of CoO doped in Glasses Prepared from Rice Hush Fly Ash in Thailand

    NASA Astrophysics Data System (ADS)

    Ruangtaweep, Y.; Kaewkhao, J.; Kirdsiri, K.; Kedkaew, C.; Limsuwan, P.

    2011-10-01

    In this work, properties of glass from local rice husk ash (RHA) in Thailand have been investigated. RHA was sintered in different temperature. Compositions and phases of RHA were analyzed by energy dispersive x-ray fluorescence spectrometer (EDXRF) and X-ray diffractometer (XRD). The glasses were melt from RHA in formula 20 Na2O : 1.0 Al2O3 : 13 B2O3 : 6.3 CaO : 0.2 Sb2O3 : 4.5 BaO : 55SiO2 (using RHA as a SiO2 source) The density values of all RHA glasses are comparable and larger than glass from pure SiO2 under same glass formula and preparing condition. These results are corresponding with refractive index values. The RHA glasses showing colorless with absorption edge in ultraviolet region were obtained. The dark blue color glasses were melted from RHA with different CoO concentration. From this part, not found to be the relation of density and refractive index of glass with CoO concentration in glass matrix. From absorption spectra, the absorption peak were appeared around 600 nm, and peak intensity are increased, with increase CoO, correspond to 4A2(4F) → 4T1(4P) state of Co2+ in tetrahedral symmetry.

  7. The preparation of uranium-doped glass reference materials for environmental measurements

    NASA Astrophysics Data System (ADS)

    Raptis, K.; Ingelbrecht, C.; Wellum, R.; Alonso, A.; De Bolle, W.; Perrin, R.

    2002-03-01

    Seven different uranium glass powders containing 5 mass% uranium with 235U abundances from natural to highly enriched have been prepared for the IRMM support programme to the International Atomic Energy Agency (IAEA) and for the IRMM external NUSIMEP quality control programme (Nuclear Signatures Interlaboratory Measurement Evaluation Programme). The particles will be primarily used, blended with (inactive) matrix glass powder in various ratios to simulate environmental samples containing "hot" particles in order to assess the performance of various separation and measurement techniques. High-purity borosilicate glass was prepared by blending of powders, melting and grinding by ball milling and jet milling to a powder of about 12 μm. A quantity of this glass was then blended with U 3O 8, melted and milled to powder. Laser diffraction measurements were made to ensure that the particle size distribution of the uranium glass matched that of the matrix glass in order to ensure homogeneous blending. The final yield was 30-40 g of each uranium glass and 1 kg of matrix glass. The glasses have been certified as reference materials for isotope abundances of uranium.

  8. Thermoluminescence response of dysprosium doped strontium tetraborate glasses subjected to electron irradiations.

    PubMed

    Lim, Tou Ying; Wagiran, H; Hussin, R; Hashim, S

    2015-08-01

    The paper presents the thermoluminescence (TL) response of strontium tetraborate glass subjected to electron irradiations at various Dy2O3 concentrations ranging from 0.00 to 1.00mol%. All glass samples exhibited single broad peak with maximum peak temperature positioned at 170-215°C. The optimum TL response was found at Dy2O3 concentration 0.75mol%. This glass showed good linearity and higher sensitivity for 7MeV compared to 6MeV electrons. Analysis of kinetic parameters showed that the glasses demonstrate second order kinetic.

  9. Processing and Characterization of In-Situ Generated Nanosilver and Er3+ Co-Doped Bromoborosilicate Glass Nanocomposites.

    PubMed

    Sarkar, Jit; Tarafder, Anal; Karmakar, Basudeb

    2015-09-01

    In the present investigation, bromoborosilicate glass of composition 6Na2O-19K2O-10BaBr2- 2Al2O3-15B2O3-48SiO2 (mole %) added with 0.2 wt% SnO, co-doped with 0.001 wt% Ag and 0.7 wt% Er2O3 in excess amount, was prepared by melt-quench technique. The metal-glass nanocomposites were derived involving a single-step in-situ thermochemical reduction of the precursor glass subjecting an isothermal heat-treatment protocol. The precursor glass and metal glass nanocomposites were characterized by dilatometer, differential scanning calorimeter, X-ray diffractometer, field emission scanning electron microscope, transmission electron microscope, Fourier transform infrared spectrometer, UV-Vis-NIR spectrophotometer, fluorimeter etc. XRD spectra represent the amorphous nature of the samples and without having any sharp peaks of silver (Ag0) and barium bromide (BaBr2). But the FESEM micrograph shows the presence of BaBr2 crystallites in clusters and the TEM micrograph shows the presence of AgO nanoparticles of different shapes and sizes. The precursor glass sample shows sharp absorption peak at 378 nm and 521 nm due to the 4G11,2 and 2H11/2 energy levels of Er3+ but glass nanocomposites exhibit another band at 410 nm due to the surface plasmon resonance of Ag0 nanoparticles. They also show sharp emis- sion peak at 1542 nm due to 4115/2 -+4l13/2 transition of Er3+ ions and prominent upconverted peaks at 630 nm (red, medium) and 645 nm (red, strong) due to 4F9/2 + 1 15/2 transition. The intensity of the absorption and upconverted peaks increases with the duration of heat treatment, having maximum intensity at 5 h and the intensity of the emission peak increases with heat treatment upto 1 h and then decreases for 5 h. Thus these metal-glass nanocomposites show enhanced photoluminescence upconversion and are promising material for different photonic applications. PMID:26716215

  10. Investigations on spectroscopic properties of Dy3+ doped zinc telluro-fluoroborate glasses for laser and white LED applications

    NASA Astrophysics Data System (ADS)

    Suthanthirakumar, P.; Marimuthu, K.

    2016-12-01

    A new series of Zinc telluro-fluoroborate glasses (ZTFB) doped with Dy3+ ions with the chemical composition (30-x) B2O3 + 30TeO2 + 16ZnO + 10ZnF2 + 7CaF2 + 7BaF2 + xDy2O3 (where x = 0.05, 0.1, 0.25, 0.5, 1 and 2 in wt%) have been synthesized by the conventional melt quenching technique and the prepared glass samples were characterized through XRD, FTIR, UV-Vis-NIR optical absorption, photoluminescence and decay spectral measurements. The XRD patterns have been recorded to confirm the amorphous nature. The FTIR spectral measurements were carried out to identify the functional groups present in the title glasses. From the energy band positions of the absorption spectra, bonding parameters (βbar and δ) have been calculated to identify the covalent/ionic nature of the metal-ligand bond present in the prepared glasses. The Judd-Ofelt (JO) intensity parameters Ωλ (λ = 2, 4 and 6) have been calculated from the oscillator strengths of the different absorption bands to understand the nature of the ligand environment around the Dy3+ ions. The radiative parameters such as transition probability (A), stimulated emission cross-section (σPE), radiative lifetime (τR) and branching ratios (βR) corresponding to the 4F9/2 → 6H15/2, 4F9/2 → 6H13/2, and 4F9/2 → 6H11/2 emission transitions have been determined using JO parameters and the refractive index values. The CIE chromaticity coordinates were calculated from the luminescence spectra to explore the dominant emission colour of the title glasses and the obtained results were discussed in detail and reported.

  11. Growth, differentiation, and migration of osteoblasts on transparent Ni doped TiO2 thin films deposited on borosilicate glass.

    PubMed

    Dhayal, Marshal; Kapoor, Renu; Sistla, Pavana Goury; Kant, Chander; Pandey, Ravi Ranjan; Govind; Saini, Krishan Kumar; Pande, Gopal

    2012-05-01

    A simple and cost effective dip coating method was used to deposit thin films of amorphous (AM) or anatase (AN) titanium dioxide (TiO(2)) on borosilicate glass substrates, either with or without prior doping of TiO(2) with nickel (Ni) cations by a specially designed sol gel technique. The objective of the study was to compare the physicochemical and biological properties of these films and assess their use in orthopedic implants or for in vitro cell biological studies. Analytical techniques such as XRD and XPS, in combination with ATR-FTIR and SEM revealed that only AN films, prepared by controlled heating up to 450°C, irrespective of prior doping with Ni, contained significant crystalline structures of variable morphologies. This observation could be linked to the carbon and oxygen contents and the availability of functional groups in the films. Cell biological studies revealed that Ni doping of TiO(2) in both AM and AN films improved the adhesion, spreading, proliferation, differentiation, and migration of MC3T3 cells. Our studies provide a new approach to prepare optically transparent metal surfaces, with tunable physicochemical properties, which could be suitable for eliciting optimal osteoinductive cell responses and permit the detailed in vitro cell biological studies of osteoblasts.

  12. Eu-doped ZnO-HfO2 hybrid nanocrystal-embedded low-loss glass-ceramic waveguides

    NASA Astrophysics Data System (ADS)

    Ghosh, Subhabrata; N, Shivakiran Bhaktha B.

    2016-03-01

    We report on the sol-gel fabrication, using a dip-coating technique, of low-loss Eu-doped 70SiO2 -(30-x) HfO2-xZnO (x = 2, 5, 7 and 10 mol%) ternary glass-ceramic planar waveguides. Transmission electron microscopy and grazing incident x-ray diffraction experiments confirm the controlled growth of hybrid nanocrystals with an average size of 3 nm-25 nm, composed of ZnO encapsulated by a thin layer of nanocrystalline HfO2, with an increase of ZnO concentration from x = 2 mol% to 10 mol% in the SiO2-HfO2 composite matrix. The effect of crystallization on the local environment of Eu ions, doped in the ZnO-HfO2 hybrid nanocrystal-embedded glass-ceramic matrix, is studied using photoluminescence spectra, wherein an intense mixed-valence state (divalent as well as trivalent) emission of Eu ions is observed. The existence of Eu2+ and Eu3+ in the SiO2-HfO2-ZnO ternary matrix is confirmed by x-ray photoelectron spectroscopy. Importantly, the Eu{}2+,3+-doped ternary waveguides exhibit low propagation losses (0.3 ± 0.2 dB cm-1 at 632.8 nm) and optical transparency in the visible region of the electromagnetic spectrum, which makes ZnO-HfO2 nanocrystal-embedded SiO2-HfO2-ZnO waveguides a viable candidate for the development of on-chip, active, integrated optical devices.

  13. Eu-doped ZnO-HfO2 hybrid nanocrystal-embedded low-loss glass-ceramic waveguides.

    PubMed

    Ghosh, Subhabrata; Bhaktha B N, Shivakiran

    2016-03-11

    We report on the sol-gel fabrication, using a dip-coating technique, of low-loss Eu-doped 70SiO2 -[Formula: see text] HfO2-xZnO (x = 2, 5, 7 and 10 mol%) ternary glass-ceramic planar waveguides. Transmission electron microscopy and grazing incident x-ray diffraction experiments confirm the controlled growth of hybrid nanocrystals with an average size of 3 nm-25 nm, composed of ZnO encapsulated by a thin layer of nanocrystalline HfO2, with an increase of ZnO concentration from x = 2 mol% to 10 mol%  in the SiO2-HfO2 composite matrix. The effect of crystallization on the local environment of Eu ions, doped in the ZnO-HfO2 hybrid nanocrystal-embedded glass-ceramic matrix, is studied using photoluminescence spectra, wherein an intense mixed-valence state (divalent as well as trivalent) emission of Eu ions is observed. The existence of Eu(2+) and Eu(3+) in the SiO2-HfO2-ZnO ternary matrix is confirmed by x-ray photoelectron spectroscopy. Importantly, the Eu[Formula: see text]-doped ternary waveguides exhibit low propagation losses (0.3 ± 0.2 dB cm(-1) at 632.8 nm) and optical transparency in the visible region of the electromagnetic spectrum, which makes ZnO-HfO2 nanocrystal-embedded SiO2-HfO2-ZnO waveguides a viable candidate for the development of on-chip, active, integrated optical devices.

  14. Use of microgravity to improve the efficiency and power output of Nd-doped laser glasses

    NASA Technical Reports Server (NTRS)

    Ray, Chandra S.

    1992-01-01

    The objectives of this research are to: (1) obtain further evidence and understand the science for the reported improvement in chemical homogeneity in glasses prepared in microgravity; and (2) study the feasibility of improving the optical and fluorescence properties, particularly, the limit for Nd(+3) concentration quenching and threshold energy for laser action for laser glasses prepared in microgravity. Attention was directed to ground based investigation whose primary purpose was to determine the suitability and conditions for processing these laser glasses in space. This report describes that the scientific and technical information required for planning flight experiments for these glasses have been obtained, and the preparation for handling and analyzing post flight samples have also been taken. Instruments required for measuring the fluorescence properties of interest have been constructed. The optical and fluorescence properties for the glasses have been measured and made available for comparative property analysis.

  15. Picosecond nonradiative processes in neodymium-doped crystals and glasses: mechansim for the energy gap law

    SciTech Connect

    Bibeau, C.; Payne, S.A.

    1997-09-29

    We present measurements of the 4G7/2 emission lifetime for 26 Nd-doped materials. A model of nonradiative decay based on dipole-dipole energy transfer is developed and found to be supported by our data.

  16. Study on the water durability of zinc boro-phosphate glasses doped with MgO, Fe2O3, and TiO2

    NASA Astrophysics Data System (ADS)

    Hwang, Moon Kyung; Ryu, Bong Ki

    2016-07-01

    The water durability of zinc boro-phosphate (PZB) glasses with the composition 60P2O5-20ZnO-20B2O3- xMeO ( x = 0, 2, 4, 6 and MeO = MgO, Fe2O3, or TiO2) (mol%) was measured, and PZB glass was studied in terms of its thermal properties, density, and FTIR characteristics. The surface conditions and corrosion byproducts were analyzed using scanning electron microscopy. When MgO, Fe2O3, and TiO2 were doped into the PZB glass, Q2 was decreased and Q1 was increased in the phosphate structure, while the number of BO4 structures increased with increasing MeO content. The density of the PZB glass was increased by the addition of Fe2O3 and TiO2, while the glass transition temperature ( T g ) and dilatometric softening temperature ( T d ) were increased when additional MgO, Fe2O3, and TiO2 were added. From the weight loss analysis (95 ◦ C, 96 h), TiO2 doped glass showed the lowest weight loss (1.70 × 10 -3 g/cm2) while MgO doped glass showed the highest value (2.44 × 10 -3 g/cm2), compared with PZB glass (3.07 × 10 -3 g/cm2). These results were discussed in terms of the Me n+ ions in the glass structure, and their different coordination numbers and bonding strengths.

  17. Thermal stability and 2.7 μm spectroscopic properties in Er3+ doped tellurite glasses

    NASA Astrophysics Data System (ADS)

    Tian, Ying; Li, Bingpeng; Chen, Rong; Xia, Jienan; Jing, Xufeng; Zhang, Junjie; Xu, Shiqing

    2016-10-01

    In present paper, the thermal stability and 2.7 μm spectroscopic properties in Er3+ doped tellurite glasses have been investigated by 980 nm laser diode pumping. Thermal analysis indicates that GeO2 modified tellurite glass has better thermal stability and anti-crystallization ability. Judd-Ofelt intensity parameters are calculated and discussed to examine the covalency characteristics based on absorption spectra. The 2.7 μm fluorescence is obtained and the lifetime can reach 124 ± 1 μs with the quantum efficiency of 61.5% in prepared samples. Moreover, higher effective emission bandwidth (136.67 nm), emission cross sections (12.75 × 10-21 cm2) and radiative transition probability (95.66s-1) at 2.7 μm are achieved. In addition, upconversion and near-infrared emission spectra are measured to elucidate energy transfer mechanism of Er3+. The results suggest that the present tellurite glass modified by GeO2 might have promising applications in mid-infrared fiber lasers.

  18. Engineering rare-earth-doped heavy metal oxide glasses for 2-5 μm lasers

    NASA Astrophysics Data System (ADS)

    Richards, Billy D. O.; Jha, Animesh; Dorofeev, Vitaly; Manzur, Tariq

    2010-04-01

    The electronic states in trivalent rare-earth ions offer an excellent opportunity for designing efficient fibre and bulk lasers for atmospheric remote sensing and LIDAR technology. The first part of this review article focuses on engineering passive fibres for 2-5 μm transmission. The fabrication of single-mode tungsten tellurite optical fibres from high purity bulk glass rods is described. Fibres with a numerical aperture of 0.1 and core diameter of 10+/-2 μm have been drawn using suction and rod-in-tube techniques of fibre preform fabrication. Losses of 2.3 dBm-1 at 974 nm have been measured. These fibres are of interest for use as passive transmission fibre or active fibres for lasing in the 2-5 μm spectral region. The use of heavy metal oxides in the fabrication of glass leads to extended infrared transmission. In the 2nd part of the review we compare the slope efficiencies of Tm3+ and Tm3+/Ho3+ doped glasses and fibres for 1950-2080 nm lasers using a range of pumping schemes in tellurite and germanium oxide hosts. We also explain the importance of choosing 1950-2080 nm tunable lasers as a pump source for stimulated emission at longer wavelengths.

  19. Structural and optical characterization of Er{sup 3+} doped zinc telluroborate glasses for green laser applications

    SciTech Connect

    Annapoorani, K.; Marimuthu, K.; Ravindran, T. R.; Murthy, N. Suriya

    2015-06-24

    A new series of Erbium doped Zinc telluroborate glasses were prepared by melt quenching technique. The stretching and bending vibrations of the B–O and Te–O bonds in the prepared glass network were explored through Raman spectra. The nature of the metal-ligand bond was determined using optical absorption spectra through Nephelauxetic ratio (β) and Bonding parameter (δ) studies. The Judd-Ofelt (JO) parameters (Ω{sub 2}, Ω{sub 4}, Ω{sub 6}) and the oscillator strengths were calculated following JO theory. The relatively higher Ω{sub 2} values reveal the higher asymmetry nature. The green emission corresponding to the {sup 2}H{sub 11/2}+{sup 4}S{sub 3/2}→{sup 4}I{sub 15/2} transition was observed at around 550 nm and the luminescence quenching occurs beyond 1.0 wt% of Erbium ion concentration. Radiative properties for the 1.0EZTB glass are found to be higher and its suitability towards green laser applications were discussed and reported.

  20. Structural characterization by x-ray methods of novel antimicrobial gallium-doped phosphate-based glasses

    SciTech Connect

    Pickup, D. M.; Moss, R. M.; Qiu, D.; Newport, R. J.; Valappil, S. P.; Knowles, J. C.; Smith, M. E.

    2009-02-14

    Antimicrobial gallium-doped phosphate-based glasses of general composition (P{sub 2}O{sub 5}){sub 0.45}(CaO){sub 0.16}(Na{sub 2}O){sub 0.39-x}(Ga{sub 2}O{sub 3}){sub x} (where x=0, 0.01, 0.03, and 0.05) have been studied using the advanced synchrotron-based techniques of Ga K-edge x-ray absorption spectroscopy and high-energy x-ray diffraction to provide a structural insight into their unique properties. The results show that the Ga{sup 3+} ions are octahedrally coordinated. Furthermore, substitution of Na{sub 2}O by Ga{sub 2}O{sub 3} strengthens the phosphate network structure because the presence of GaO{sub 6} octahedra inhibits the migration of the remaining Na{sup +} ions. The results are discussed in terms of the use of Na{sub 2}O-CaO-P{sub 2}O{sub 5} glasses as controlled-delivery devices for antimicrobial Ga{sup 3+} ions in biomedical applications. We are thereby able to relate the atomic-scale environment of the Ga{sup 3+} ions beneficially to the glass dissolution, and thus to their ability to disrupt bacterial cell activity by usurping the role of iron.