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1

Neodymium-doped barium borate glasses as fluorescent concentrators for the infrared spectral range  

NASA Astrophysics Data System (ADS)

Neodymium-doped barium borate glasses are investigated for their potential as fluorescent concentrators for the near infrared spectral range. Additional doping of the glasses with silver oxide and subsequent heat treatment leads to a reduction of the doped silver ions and to the formation of metallic silver nanoparticles. The formation of the silver nanoparticles is indicated by a broad surface plasmon-related extinction band at approximately 410 nm. The influence of the silver nanoparticles on the fluorescence properties is investigated.

Dyrba, Marcel; Wiegand, Marie-Christin; Ahrens, Bernd; Schweizer, Stefan

2012-06-01

2

Elastic properties of Li+ doped lead zinc borate glasses  

NASA Astrophysics Data System (ADS)

Glasses in the system 0.25PbO-(0.25-x) ZnO-0.5B2O3-xLi2O have been prepared by the melt quenching technique. Elastic properties, DSC studies have been employed to study the role of Li2O in the present glass system. Elastic properties and Debye temperature have been determined using pulsed echo ultrasonic interferometer operating at 10MHz. Sound velocities Vl, Vt and elastic moduli decrease up to 5 mol% and then gradually increase with increase in Li2O concentration. Debye temperature and the glass transition temperature decreases with increase in Li2O. Densities remains almost constant up to 15 mol% Li2O concentration and increases monotonically while the molar volume decreases with the increase of Li2O concentration. The results are discussed in view of the borate structural network and dual role of Zn and Pb in these glasses.

Rajaramakrishna, R.; Lakshmikantha, R.; Anavekar, R. V.

2014-04-01

3

Tunable luminescence of Dy3+ single-doped and Dy3+/Tm3+ co-doped tungsten borate glasses  

NASA Astrophysics Data System (ADS)

RE3+ (RE3+ = Tm3+, Dy3+) ion single and co-doped tungsten borate glasses for white light emitting diodes (LEDs) were prepared by melt quenching method. Emission and excitation spectra of the glasses were measured. The color of luminescence can be tuned by changing the composition of glass matrix or the concentrations of Tm3+ and Dy3+ ions. White light emission can be achieved from 0.5Dy3+ single-doped 15WO3-25La2O3-60B2O3 and 0.4Tm3+/1.5Dy3+ co-doped 50WO3-25La2O3-25B2O3 glasses. In addition, energy transfers between Tm3+ and Dy3+ were also analyzed. The Dy3+/Tm3+ co-doped tungsten borate glasses may be potential candidates for white LED application.

Hu, J.; Gong, X. H.; Chen, Y. J.; Huang, J. H.; Lin, Y. F.; Luo, Z. D.; Huang, Y. D.

2014-12-01

4

Visible photon multiplication in Ce3+–Tb3+ doped borate glasses for enhanced solar cells  

NASA Astrophysics Data System (ADS)

Visible photon multiplication is exposed in the Ce3+–Tb3+ doped alkaline-earth borate (LKZBSB) glass system. Efficient green and blue fluorescences originate from Tb3+ and Ce3+ emitting centres, respectively. Evaluation of absolute spectral parameters reveals that the quantum yield of Tb3+ single doped LKZBSB glasses is ~8% under UVA radiation. Furthermore, with the introduction of Ce3+ into the Tb3+ doping system, the effective excitation wavelength range and the emission intensity of Tb3+ in LKZBSB glasses are remarkably expanded and improved by a maximum sensitization factor of ~52 in the UVB spectral region. These results demonstrate that the Ce3+–Tb3+ doped LKZBSB glass system has promising potential as an efficient UV ? Visible radiation conversion layer for the enhancement of solar cell efficiency, including cells employed in outer space.

Yang, Peng; Chen, Baojie; Shen, Lifan; Bun Pun, Edwin Yue; Lin, Hai

2014-11-01

5

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

NASA Astrophysics Data System (ADS)

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.

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

2011-07-01

6

Energy transfer and luminescence studies of Pr 3+ , Yb 3+ co-doped lead borate glass  

NASA Astrophysics Data System (ADS)

Lead borate glass samples doped with the tripositive lanthanide ions Pr 3+ and Yb 3+ were synthesized by the conventional melting-quenching method. The luminescence properties and energy transfer process from Pr 3+ to Yb 3+ were investigated. Upon ultraviolet excitation, the room temperature luminescence decay curve of a sample containing only a low concentration of Pr 3+ exhibited monoexponential decay from 1D 2 with the lifetime 37 ?s, without emission from 3P 0. The room temperature Pr 3+ emission intensity decreased with the increase of Yb 3+ mole ratio in the glass. Under the excitation of 454.5 nm at 10 K, a broad red emission band centered at 605 nm, and an NIR emission band at 995 nm were observed in the co-doped lead borate glass, originating from Pr 3+ and Yb 3+ ions, respectively. The decay curves of the 1D 2 emission from Pr 3+ with addition of Yb 3+ in lead borate glass show non-monoexponential character, and are best described by a stretched exponential function. The average 1D 2 decay time decreases considerably with the addition of Yb 3+ in the glass. Decay curve fitting using a modified Inokuti-Hirayama expression indicates dipole-dipole energy transfer from Pr 3+ to Yb 3+, which is consistent with the expected cross-relaxation scheme. There is a good agreement of the estimated overall energy transfer efficiency obtained from the integrals under the normalized decay curves, or from the lifetimes fitted by the stretched exponential function, or from the average decay times.

Wen, Hongli; Tanner, Peter A.

2011-09-01

7

Elastic properties of silver borate glasses doped with praseodymium oxide  

SciTech Connect

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.

Gowda, G. V. Jagadeesha [Dept. of Physics, Sapthagiri College of Engineering, Bangalore-560057 (India); Eraiah, B. [Dept. of Physics, Bangalore University, Bangalore-560056 (India)

2014-04-24

8

Optical properties of Nd3+ doped bismuth zinc borate glasses.  

PubMed

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 (4)F3/2 to (4)I9/2, (4)I11/2 and (4)I13/2 transitions in the near infrared region. The emission intensity of the (4)F3/2 to (4)I11/2 transition increases with increase of Nd(3+) concentration up to 1 mol% and then concentration quenching is observed for 2 mol% of Nd(3+) concentration. The lifetimes for the (4)F3/2 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 Nd(3+) 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. PMID:24326260

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

2014-03-25

9

Optical studies of Sm³? ions doped zinc alumino bismuth borate glasses.  

PubMed

Zinc Alumino Bismuth Borate (ZnAlBiB) glasses doped with different concentrations of samarium (Sm(3+)) 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 Sm(3+) 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 Sm(3+) 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 (4)G5/2 level of Sm(3+) ions. From the measured emission cross-sections, branching ratios, strong photoluminescence features and CIE chromaticity coordinates, it was found that 1 mol% of Sm(3+) ions doped ZnAlBiB glasses are most suitable for the development of visible orange-red lasers. PMID:24530709

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

2014-05-01

10

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

NASA Astrophysics Data System (ADS)

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.

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

11

Structural and optical properties of lithium sodium borate glasses doped with Sm3+ ions  

NASA Astrophysics Data System (ADS)

Absorption and emission spectra of Sm3+ doped lithium sodium borate (LNB) have been reported. The samples were prepared by the melt-quenching technique and characterized by X-ray diffraction (XRD), diffraction thermal analysis (DTA), Fourier transforms infrared (FTIR) spectroscopy and field emission scanning electron microscopy (FESEM). From the thermo-grams spectrum, glass transition (Tg), crystallization (Tc) and melting temperatures (Tm) have been evaluated. Direct and indirect optical band gaps have been calculated based on the glasses UV absorption spectra. These glasses have shown strong nine absorption bands with hypersensitive transition at 1221 nm (6H5/2?4H3/2) and five emission bands for the transition at 4I7/2?6H13/2 (green color), 4I7/2?6H7/2 (orange color), 4I7/2?6H9/2 (orange color), 4I7/2?6H11/2 (red color) and 4I7/2?6H13/2 (red color) with performing an excitation of 400 nm. The oscillator strengths, refractive index, ions concentration, polaron radius and other parameters have been calculated for each dopant.

Dawaud, R. S. E. S.; Hashim, S.; Alajerami, Y. S. M.; Mhareb, M. H. A.; Maqableh, M. M.; Tamchek, N.

2014-07-01

12

Ho3+-doped strontium-aluminium-bismuth-borate glasses for green light emission.  

PubMed

Strontium-aluminium-bismuth-borate glasses (SAlBiB) doped with different concentrations of Ho(3+) were prepared using conventional melt quenching technique and their structural and optical properties investigated. X-ray diffraction and scanning electron microscopy analysis were used to study the structural properties. Optical properties were studied by measuring the optical absorption and visible luminescence spectra. The Judd-Ofelt (J-O) theory was applied to evaluate J-O intensity parameters, ?(?) (? = 2, 4 and 6). Using J-O intensity parameters, radiative properties such as spontaneous transition probabilities (A(R)), branching ratios (?(R)) and radiative lifetimes (?(R)) were determined. From the emission spectra, a strong green emission nearly at 549 nm corresponding to the transition, (5)S2 ((5)F4)?(5)I(8) was observed. Emission peak positions (?(P)), effective bandwidths (??(eff)) and stimulated emission cross-sections (?(p)) were calculated for the observed emission transitions, (5)F3 ?(5)I(8), (5)S2((5)F4)?(5)I(8) and (5)F5 ?(5)I(8) of Ho(3+) in all the glass matrices. Chromaticity color coordinates were calculated using the emission spectra. The experimental results suggest that SAlBiB glass matrix with 1.5 mol% of Ho(3+) has better emission properties. PMID:24519914

Rajesh, D; Dhamodhara Naidu, M; Ratnakaram, Y C; Balakrishna, A

2014-11-01

13

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

PubMed

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. PMID:24681645

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

2014-08-01

14

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

NASA Astrophysics Data System (ADS)

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 60 mol.%) reveals strong charge transfer UV absorption bands which are related to unavoidable trace iron impurities (Fe3+) 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 580 nm. 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.

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

2014-12-01

15

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

PubMed

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. PMID:24983922

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

2014-12-10

16

Dosimetric properties of germanium doped calcium borate glass subjected to 6 MV and 10 MV X-ray irradiations  

NASA Astrophysics Data System (ADS)

Germanium doped calcium borate glasses are investigated in term of thermoluminescence properties to seek their possibility to use as glass radiation dosimeter. The samples were exposed to 6 MV, and 10 MV photon beams in a dose range of 0.5-4.0 Gy. There is a single and broad thermoluminescence glow curve that exhibits its maximum intensity at about 300 °C. Linear dose response behavior has been found in this dose range for the both photon energies. Effective atomic number, TL sensitivity, and reproducibility have also been studied. It is found that the sensitivity of germanium doped sample at 6 MV is only 1.28% and it is superior to the sensitivity at 10 MV. The reproducibility of germanium doped sample is good with a percentage of relative error less than 10%. The results indicate that this glass has a potential to be used as a radiation dosimetry, especially for application in radiotherapy.

Tengku Kamarul Bahri, T. N. H.; Wagiran, H.; Hussin, R.; Saeed, M. A.; Hossain, I.; Ali, H.

2014-10-01

17

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

NASA Astrophysics Data System (ADS)

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.

Ottomeyer, Megan

18

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

PubMed

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. PMID:24929526

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

19

FTIR studies of some vanadyl ion doped calcium oxychloride borate glasses  

NASA Astrophysics Data System (ADS)

The borate glass system with composition xCaCl2?(30-x)?CaO?70B2O3+2mol% of V2O5(x = 0,0.02,0.05,0.07,0.10,0.12,0.15,0.20,0.25,0.30) has been prepared with the traditional melt-quenching technique. The FTIR study has been carried out using Perkin Elmer Frontier FTIR with ATR accessory in the mid IR range. The density, molar theoretical optical basicity is calculated so as to determine the structure and covalency in the glass network so formed. The spectra reveal absence of boroxol ring and presence of absorption bands corresponding to the combined contributions of tri and tetra borate stretching vibrations. This confirms the network modifier nature of magnesium chloride. The increasing basicity reveals decrease in the covalence nature of oxygen and octahedral enhancement in the vanadyl ion nature as we replace the CaO content with CaCl2. The increase in molar volume may be due to the increase in openness of the network structure.

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

2013-06-01

20

Judd-Ofelt analysis and spectral properties of Dy3+ ions doped niobium containing tellurium calcium zinc borate glasses  

NASA Astrophysics Data System (ADS)

Niobium containing tellurium calcium zinc borate (TCZNB) glasses doped with different concentrations of Dy3+ ions were prepared by the melt quenching method and their optical properties have been studied. The Judd-Ofelt (J-O) intensity parameters ?t (t=2, 4 and 6) were calculated using the least square fit method. Based on the magnitude of ?2 parameter the hypersensitivity of 6H15/2?6F11/2 has also been discussed. From the evaluated J-O intensity parameters as well as from the emission and lifetime measurements, radiative transition properties such as radiative transition probability rates and branching ratios were calculated for 4F9/2 excited level. It is found that for Dy3+ ion, the transition 4F9/2?6H13/2 shows highest emission cross-section at 1.0 mol% TCZNB glass matrix. From the visible luminescence spectra, yellow to blue (Y/B) intensity ratios and chromaticity color coordinates were also estimated. The TCZNB glasses exhibit good luminescence properties and are suitable for generation of white light.

Ravi, O.; Reddy, C. Madhukar; Reddy, B. Sudhakar; Deva Prasad Raju, B.

2014-02-01

21

Glass composition and excitation wavelength dependence of the luminescence of Eu{sup 3+} doped lead borate glass  

SciTech Connect

This work explores the relationship between the bandwidth of luminescence spectral features and their relative intensities, using glasses doped with europium, Eu{sup 3+}, over a wide composition range. Glasses of composition (B{sub 2}O{sub 3}){sub 70}(PbO){sub 29}(0.5Eu{sub 2}O{sub 3}){sub 1} and (B{sub 2}O{sub 3}){sub z}(PbO){sub 99.6-z}(0.5Eu{sub 2}O{sub 3}){sub 0.4}, (z = 20, 30, 40, 60, 70), were prepared by the melting-quenching technique. Variable-wavelength measurements by the prism-coupling method enabled interpolation of refractive index at selected wavelengths. Diffuse reflectance spectra confirmed the incorporation of Eu{sup 3+} into the glass, and scanning electron microscopy displayed that this was in a homogeneous manner. Vibrational spectra showed a change in boron coordination from BO{sub 3} to BO{sub 4} units with increase of PbO content in the glass. Multi-wavelength excited luminescence spectra were recorded for the glasses at temperatures down to 10 K and qualitative interpretations of spectral differences with change of B{sub 2}O{sub 3} content are given. The quantitative analysis of {sup 5}D{sub 0} luminescence intensity-bandwidth relations showed that although samples with higher boron content closely exhibit a simple proportional relationship with band intensity ratios, as expected from theory, the expression needs to be slightly modified for those with low boron content. The Judd-Ofelt intensity analysis of the {sup 5}D{sub 0} emission spectra under laser excitations at low temperature gives {Omega}{sub 2} values within the range from (3.9-6.5) x 10{sup -20} cm{sup 2}, and {Omega}{sub 4} in the range from (4.1-7.0) x 10{sup -20} cm{sup 2}, for different values of z. However, no clear monotonic relation was found between the parameter values and composition. The Judd-Ofelt parameters are compared with those from other systems doped with Eu{sup 3+} and are found to lie in the normal ranges for Eu{sup 3+}-doped glasses. The comparison of parameter values derived from the 10 K spectra with those from room temperature spectra for our glasses, which are fairly constant for different compositions, shows that site selection occurs at low temperature.

Wen Hongli; Duan, Chang-Kui; Jia Guohua; Tanner, Peter A. [Department of Biology and Chemistry, City University of Hong Kong, Tat Chee Avenue, Kowloon (Hong Kong); Brik, Mikhail G. [Institute of Physics, University of Tartu, Riia 142, Tartu 51014 (Estonia)

2011-08-01

22

Spectroscopy and energy transfer in lead borate glasses doubly doped with Dy(3)(+)-Tb(3+) and Tb(3)(+)-Eu(3+) ions.  

PubMed

Lead borate glasses doubly doped with Dy(3)(+)-Tb(3+) and Tb(3+)-Eu(3+) were investigated using optical spectroscopy. Luminescence spectra of rare earths were detected under various excitation wavelengths. The main green emission band due to (5)D4?(7)F5 transition of Tb(3+) is observed under excitation of Dy(3+), whereas the main red emission band related to (5)D0?(7)F2 transition of Eu(3+) is successfully observed under direct excitation of Tb(3+). In both cases, the energy transfer processes from Dy(3+) to Tb(3+) and from Tb(3+) to Eu(3+) in lead borate glasses occur through a nonradiative processes with efficiencies up to 16% and 18%, respectively. The presence of energy transfer process was also confirmed by excitation spectra measurements. PMID:24824577

Pisarska, Joanna; Kos, Agnieszka; Pisarski, Wojciech A

2014-08-14

23

Effect of ZnSe and CdSe nanoparticles on the fluorescence and optical band gap of Sm3+ doped lead borate glasses  

NASA Astrophysics Data System (ADS)

For the first part of this work, we prepared a series of Sm-doped lead borate (PbO-B2O3) glasses containing zinc selenide (ZnSe) and cadmium selenide (CdSe) nanoparticles (NPs) and studied the Sm 3+ fluorescence by varying the glass composition and size of the NPs. We have chosen these heavy metal oxide glasses to incorporate Sm3+ ions because they have large glass forming region, high refractive index, and good physical and thermal stability. Lead borate glasses with the following compositions xPbO:(96.5-x)B2O 3:0.5Sm2O3:3ZnSe/CdSe, x=36.5 and 56.5 mol%) are prepared using the melt-quenching method. Transmission electron microscopy characterization was done to confirm both nucleation and growth of the NPs for different annealing times. Fluorescence spectra of these samples are obtained with the excitation wavelengths at 403 and 477nm. Three fluorescence transitions are observed at 563 nm, 598 nm and 646 nm. The transition at 646 nm is a electric dipole (ED) transition that strongly depends on the covalency of the Sm-O bond and the asymmetry of the crystal field at the Sm3+ site. The 646 nm/598 nm fluorescence intensity ratio has been studied for different annealing times and PbO concentration for both ZnSe and CdSe samples. Longer annealing times tend to make the crystal field at the Sm3+ site more symmetric in nature for these glasses. The presence of CdSe NPs is seen to produce the greatest influence on the fluorescence intensity ratio. This is believed to be due to the larger size of the CdSe nanoparticles and its stronger influence on Sm3+ ions. The second part of this work was dedicated to the understanding of the optical band gap of samarium doped lead borate glasses with and without ZnSe/CdSe NPs. Optical absorption spectra for all these glass samples show their absorption edge in the ultraviolet region. Detailed analysis of the absorption edge was carried out using the Mott-Davis model and the optical band gap and the width of the tail in the band gap (Urbach edge) were obtained. Our glass samples show both direct and indirect transitions. For samples without the NPs, the optical band gap decreases with increasing PbO concentration. The presence of ZnSe NPs shows a similar trend. The introduction of CdSe NPs, however, shows an increase in the optical band gap with increase in PbO contents. Our results indicate that CdSe NPs show markedly different effect on the optical properties of lead borate glasses compared to ZnSe NPs. TEM characterization shows that CdSe NPs are considerably larger than ZnSe NPs. These size differences could produce significant differences in the electronic properties of these NPs and their interaction with the glass matrices.

Fatokun, Stephen O.

24

Bioactive borate glass coatings for titanium alloys  

Microsoft Academic Search

Bioactive borate glass coatings have been developed for titanium and titanium alloys. Glasses from the Na2O–CaO–B2O3 system, modified by additions of SiO2, Al2O3, and P2O5, were characterized and compositions with thermal expansion matches to titanium were identified. Infrared and X-ray diffraction\\u000a analyses indicate that a hydroxyapatite surface layer forms on the borate glasses after exposure to a simulated body fluid

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

2008-01-01

25

Er{sup 3+}-doped strontium lithium bismuth borate glasses for broadband 1.5 {mu}m emission - optical properties  

SciTech Connect

Strontium lithium bismuth borate glasses (SLBiB) doped with various concentrations of Er{sup 3+} were prepared using conventional melt quench technique and investigated their optical properties. The amorphous nature of the prepared glass samples was confirmed by X-ray diffraction and SEM analysis. Optical properties were studied by measuring the optical absorption and near infrared luminescence spectra at room temperature. Judd-Ofelt (J-O) theory has been applied for the f.f transitions of Er{sup 3+} ions to evaluate J-O intensity parameters, {Omega}{lambda} ({lambda} = 2, 4 and 6). Using the J-O intensity parameters, radiative properties such as transition probabilities (A{sub R}), branching ratios ({beta}) and radiative lifetimes ({tau}) are estimated for certain transitions. From the emission spectra, peak emission-cross sections ({sigma}{sub p}) and products of stimulated emission cross-section and full width at half maximum ({sigma}{sub p} Multiplication-Sign FWHM) were calculated for the observed emission transition, {sup 4}I{sub 13/2}{yields}{sup 4}I{sub 15/2}.

Rajesh, D.; Balakrishna, A.; Ratnakaram, Y. C. [Department of Physics, Sri Venkateswara University, Tirupati-517502 (India)

2013-02-05

26

Comparative study of ion conducting pathways in borate glasses  

NASA Astrophysics Data System (ADS)

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.

Hall, Andreas; Adams, Stefan; Swenson, Jan

2006-11-01

27

Structural properties of Zinc Lithium borate glass  

NASA Astrophysics Data System (ADS)

Zinc Lithium Borate glasses of different composition were prepared with the aim of using it for thermoluminescence dosimetry. Melt quenching method was adopted in this process. Fourier transform Infrared (FTIR) spectroscopy and UV-vis-NIR spectroscopy techniques were employed to investigate the infrared spectra and energy band gap of different composition of Zinc Lithium Borate glasses. X-ray diffraction analysis was used to confirm the amorphous nature of the glass samples. Glass forming ability and stability of the glass was checked using Differential thermal analysis (DTA). Density, molar volume, refractive index parameters have been analyzed in the light of different concentration of the modifier. The active vibrational modes of 1200-1600 cm-1 for B-O stretching of BO3 units, 800-1200 cm-1 for B-O stretching of BO4 units and 400-800 cm-1 for bending vibration of various borate segments were detected. Addition of ZnO to lithium borate shows its influence in converting the dominant BO3 group to BO4 group. BO4 are known for creating complex defects, a situation that established deep and stable traps good for thermoluminescence phenomena. From optical data, direct and indirect energy band gap has been calculated using the data obtained from UV-vis-NIR spectroscopy. Both direct and indirect band gaps decrease with the increase of modifier Li2CO3.

Saidu, A.; Wagiran, H.; Saeed, M. A.; Alajerami, Y. S. M.

2014-09-01

28

The effect of Ce3+ ions on the spectral and decay characteristics of luminescence phosphate-borate glasses doped with rare-earth ions  

NASA Astrophysics Data System (ADS)

The luminescent characteristics of Li2O-B2O3-P2O5-CaF2 (LBPC) glasses doped with Gd3+ and Tb3+ ions and codoped with Ce3+ are studied by pulsed optical spectrometry under electron beam excitation. It is found that in glass with Ce3+ and Gd3+ ions a decrease in the decay time of gadolinium luminescence in the 312-nm band (6 P J ? 8 S 7/2) was observed. It is shown that in the glass LBPC: Tb, Ce, an increase in the emission intensity in the main radiative transitions in terbium ion was observed. In the kinetics of luminescence band 545 nm of LBPC: Tb, Ce glasses, is present stage of buildup, the character of which changes with the doped of Ce3+ ions. The mechanism of energy transfer in LBP glasses doped with rare elements is discussed.

Valiev, D. T.; Polisadova, E. F.; Belikov, K. N.; Egorova, N. L.

2014-05-01

29

UNCORRECTEDPROOF 2 Optical properties of bismuth borate glasses  

E-print Network

UNCORRECTEDPROOF 2 Optical properties of bismuth borate glasses 3 Isabella-Ioana Oprea, Hartmut in the binary system bismuth oxide (Bi2O3)­boric oxide (B2O3) are measured for the composition 8 range 25­65 mol.70.Ce; 78.20.Ci 13 Keywords: Bismuth borate; Glass; Refractive index; Optical properties 14 1

Osnabrück, Universität

30

Acoustical investigations of borate glasses containing oxides of some transition elements and ferric oxide dopants  

NASA Astrophysics Data System (ADS)

Glass samples of manganese oxide borate and zinc oxide borate (with and without ferric oxide doping) have been prepared to study their acoustical, mechanical, and thermal behavior as function of composition. Sound velocities and attenuation measurements in these glass systems at 1,2, and 5 MHz give elastic moduli, Poissons ratio, micro-hardness, acoustic impedance, internal friction, thermal expansion coefficient and Debye and softening temperatures. Structural changes involve boron anomaly, field strengths of cations, difference in ionic radii, and charge state of iron. Makishima-Mackenzie (theoretical model) and IR and NGR techniques confirm the conclusions arrived at. The network modifier (NWM) is varied from 25 to 45 mol% for manganese oxide borate and from 15 to 40 mol% with 10 mol% doping of ferric oxide. For zinc oxide borate glasses, it varies from 26 to 34 mol% and with 10 mol% of ferric oxide, its variation is from 15 to 35 mol%. Impact of doping by ferric oxide on the properties of these glass systems have been investigated.

Bhatti, Surjit Singh; Singh, Kanwar Jit

2003-04-01

31

Angiogenic effects of borate glass microfibers in a rodent model.  

PubMed

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

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

2014-12-01

32

Spectroscopic analysis of Ho3+ transitions in different modifier oxide based lithium-fluoro-borate glasses  

NASA Astrophysics Data System (ADS)

In recent investigations it was observed that the presence of different structural groups in borate glasses was favorable for spectroscopic investigations of rare earth doped borate glasses. Consequent to these observations, the heavy metal fluoride glasses doped with Ho3+ ions received much attention due to their wide transparency in the ultraviolet to infrared region. Keeping these observations in view, the present paper makes an attempt to present spectral investigations of Ho3+ doped lithium-fluoro-borate glasses of the compositions Li2B4O7-BaF2-NaF-MO (where M=Mg, Ca, Cd and Pb), Li2B4O7-BaF2-NaF-MgO-CaO and Li2B4O7-BaF2-NaF-CdO-PbO. These rare earth doped glasses were synthesized by melt quenching technique and an investigation was carried out to observe the structural (SEM and FT-IR) and optical (absorption and luminescence) properties. The paper also aims at the determination of three phenomenological Judd-Ofelt intensity parameters and special attention was paid to study the emission properties by employing the J-O intensity parameters. The visible emission spectra of Ho3+ ion in different lithium-fluoro-borate glasses were recorded by exciting the samples at 409 nm. The results revealed that among all the glass matrices, cadmium glass matrix have shown higher stimulated emission cross-section, which indicates that this is a good lasing material at this wavelength and highly useful for laser excitation.

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

2014-10-01

33

Impact of vanadium ions in barium borate glass  

NASA Astrophysics Data System (ADS)

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.

Abdelghany, A. M.; Hammad, Ahmed H.

2015-02-01

34

Interpretation of the IR spectra of alkali borate glasses  

SciTech Connect

This paper describes methods of interpretation of the IR spectra of alkali borate glasses. In view of the difficulties which are encountered in a strict interpretation of the IR spectra of crystalline oxygen-containing compounds with complex anions, semiempirical methods of interpretation are commonly used. The existence of glasses of groups with an atomic (ionic) arrangement close to that in the crystalline compounds makes it possible to a certain extent to use the spectra of crystalline compounds in the interpretation of the IR spectra of glasses. The alkali borate glass systems were chosen for this study because the information on their structure is the most detailed by comparison with other borate glasses. IR spectrospcopy showed that the spectral regions in which fundamental asymmetrical stretching vibrations in BO/sub 3/ and BO/sub 4/ polyhedra occur, in most cases, are fairly clearly defined independently of the combined or separate presence of these polyhedra. It is proposed that the bands in the IR spectra of sodium and lithium borate glasses be assigned to vibrations mostly localized on specific fragments of polyborate groups present in the glasses. The data from IR spectroscopy confirms that tetraborate groups are present in lithium borate glasses.

Chekhovskii, V.G.

1985-11-01

35

UNCORRECTED 2 Luminescence of erbium-doped bismuthborate glasses  

E-print Network

UNCORRECTED PROOF 2 Luminescence of erbium-doped bismuth­borate glasses 3 Isabella-Ioana Oprea Received 26 May 2005; accepted 12 July 2005 7 Abstract 8 Absorption and luminescence properties of erbium for the composition range 25­65 mol% Bi2O3. A Judd­Ofelt analysis of the typical erbium bands in the absorption

Osnabrück, Universität

36

Barium–borate–flyash glasses: As radiation shielding materials  

Microsoft Academic Search

The attenuation coefficients of barium–borate–flyash glasses have been measured for ?-ray photon energies of 356, 662, 1173 and 1332keV using narrow beam transmission geometry. The photon beam was highly collimated and overall scatter acceptance angle was less than 3°. Our results have an uncertainty of less than 3%. These coefficients were then used to obtain the values of mean free

Sukhpal Singh; Ashok Kumar; Devinder Singh; Kulwant Singh Thind; Gurmel S. Mudahar

2008-01-01

37

Structural and optical properties of Nd3+ in lithium fluoro-borate glass with relevant modifier oxides  

NASA Astrophysics Data System (ADS)

Modifier oxides (MgO, CaO, CdO and PbO) based Nd3+ doped lithium fluoro-borate glasses were prepared by using the conventional melt quenching technique. The structural and optical properties of all lithium fluoro-borate glasses were characterized by means of X-ray diffraction and SEM analysis (structural), optical absorption, near infrared luminescence and lifetime decay measurements(optical). Broad XRD spectra and smooth surface of SEM image analysis reveals that these glasses have amorphous nature. Judd-Ofelt intensity parameters were calculated and used to explain the structural properties and to determine the radiative properties (radiative transition probabilities, branching ratios and radiative lifetimes) of efficient meta stable states. By pumping with diode laser excitation source at 805 nm, a broader NIR emission transition, 4F3/2 ? 4I11/2 was observed. This transition possesses large stimulated emission cross-section (?p) and branching ratio (?) values. These values are compared with another Nd3+ doped glass. The decay from the 4F3|2 level is found to be bi-exponential. The 4F3/2 level gives the highest quantum efficiency for all Nd3+ doped lithium fluoro-borate glasses. It indicates the efficient laser emission at 1.06 ?m.

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

2013-10-01

38

Photoluminescence of a Te4+ center in zinc borate glass.  

PubMed

Photoluminescent (PL) properties related to Te(4+) species in zinc borate glasses are examined. Broad emission was observed by the excitation of the PL excitation peak of Te(4+) present at the optical absorption edge. The emission intensity of Te(4+) in 5TeO(2)-50ZnO-45B(2)O(3) glass was thermally quenched in a temperature region over 100 K, suggesting that concentration quenching preferentially occurred. The lifetime of the emission was approximately 2.5 ?s, which is characteristic of relaxation from the triplet excitation state of an ns(2)-type center. PMID:24081051

Masai, Hirokazu; Yamada, Yasuhiro; Okumura, Shun; Kanemitsu, Yoshihiko; Yoko, Toshinobu

2013-10-01

39

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

PubMed

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. PMID:24840491

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

2014-10-15

40

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

NASA Astrophysics Data System (ADS)

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 × 104 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 Fe3+). The V2O5-doped glasses reveal an extra band at 380 nm and the high V2O5-content glass also shows a further band at about 420 nm. The observed optical spectrum indicates the presence of vanadium ions mainly in the pentavalent state (d0 configuration). The surplus band at 420 nm 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 Fe3+ ions by photochemical reactions with the presence of high content (45 mol%) 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.

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

2014-10-01

41

Luminescence properties of Sm{sup 3+} impurities in strontium lithium bismuth borate glasses  

SciTech Connect

In the present work, different concentrations of Sm{sup 3+}-doped strontium lithium bismuth borate glasses (SLBiB) were prepared by melt quench technique. The amorphous nature of the prepared glass samples was confirmed by X-ray diffraction and SEM analysis. Using the J-O intensity parameters, emission and decay measurements various radiative properties are studied. The nature of decay curves of {sup 4}G{sub 5/2} level for different Sm{sup 3+} ion concentrations in SLBiB glasses has been analyzed. The intensities of observed emission peaks and measured lifetimes decrease with the increase of Sm{sup 3+} ion concentration which may be due to energy transfer between excited Sm{sup 3+} ions through cross-relaxations and resonant energy channels.

Rajesh, D.; Ratnakaram, Y. C.; Seshadri, M.; Balakrishna, A. [Department of Physics,Sri Venkateswara University,Tirupati-517502 (India)

2012-06-05

42

Synthesis and studies on microhardness of alkali zinc borate glasses  

SciTech Connect

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.

Subhashini,, E-mail: subhashini.p.p@gmail.com; Bhattacharya, Soumalya, E-mail: subhashini.p.p@gmail.com; Shashikala, H. D., E-mail: subhashini.p.p@gmail.com; Udayashankar, N. K., E-mail: subhashini.p.p@gmail.com [Department of Physics, National Institute of Technology Karnataka, Surathkal-575025 (India)

2014-04-24

43

Narrow energy gap between triplet and singlet excited states of Sn2+ in borate glass.  

PubMed

Transparent inorganic luminescent materials have attracted considerable scientific and industrial attention recently because of their high chemical durability and formability. However, photoluminescence dynamics of ns(2)-type ions in oxide glasses has not been well examined, even though they can exhibit high quantum efficiency. We report on the emission property of Sn(2+)-doped strontium borate glasses. Photoluminescence dynamics studies show that the peak energy of the emission spectrum changes with time because of site distribution of emission centre in glass. It is also found that the emission decay of the present glass consists of two processes: a faster S1-S0 transition and a slower T1-S0 relaxation, and also that the energy difference between T1 and S1 states was found to be much smaller than that of (Sn, Sr)B6O10 crystals. We emphasize that the narrow energy gap between the S1 and T1 states provides the glass phosphor a high quantum efficiency, comparable to commercial crystalline phosphors. PMID:24345869

Masai, Hirokazu; Yamada, Yasuhiro; Suzuki, Yuto; Teramura, Kentaro; Kanemitsu, Yoshihiko; Yoko, Toshinobu

2013-01-01

44

A new study on bismuth doped oxide glasses.  

PubMed

Spectroscopic properties of bismuth doped borate, silicate and phosphate glasses have been reinvestigated in this work. It shows the typical decay time of Bi(3+) is around 500ns rather than 2.7-to-3.9 ?s reported by Parke and Webb at room temperature. Introduction of higher content either alkali or alkali earth into borate glasses favors the Bi(3+) emission. As the contents increase excitation peak shifts regularly red while emission peak shows reverse trend. This, as revealed by Huang-Rhys factor, is due to the weakening of coupling between bismuth and glass host, and it can be interpreted within the frame of configurational coordinate diagrams. Differently, as bismuth concentration increases, both the excitation and emission shift red. The unknown origin of red emission from bismuth doped calcium or magnesium phosphate glass has been identified as Bi(2+) species on the basis of excitation spectrum and emission lifetime particularly after comparing with Bi(2+) doped materials. No near infrared (NIR) emission can be detected in these glasses within instrument limit. PMID:22772261

Xu, Wenbin; Peng, Mingying; Ma, Zhijun; Dong, Guoping; Qiu, Jianrong

2012-07-01

45

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

PubMed

We have synthesized TiO2 doped strontium borate glasses, 70B2 O3 -(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. © 2014 Wiley Periodicals, Inc. J Biomed Mater Res Part A, 2014. PMID:25366812

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

2014-11-01

46

Interpretation of IR spectra for lithium and sodium borate glasses  

SciTech Connect

In the boron-oxygen groupings of crystalline and vitreous borates, such as triborate, tetraborate, and pentaborate, where B{sup III}-O(B{sup III}) and B{sup III}-O(B{sup IV}) bonds are present at the same time, one may arbitrarily single out groups of atoms with such bonds, similar to pyroborate and chain metaborate groupings in terms of structure and in the predominant localization of vibrations. From an analysis of what is known about the origin of bands in the IR spectra of the glasses investigated over the entire range of their compositions, may attribute the 1150-1300 cm{sup -1} bands mainly to the stretching vibrations of atoms in groups with B{sup III}-O(B{sup III}) bonds and, in glasses low in B{sub 2}O{sub 3}, also in BO{sup 3-}{sub 3} groups; in the 1300-1500 cm{sup -1} range, this holds for groups with B{sup III}-O(B{sup IV}) and/or B{sup III}-O{sup -} bonds.

Chekhovskii, V.G. [Institute of Technology, St. Petersburg (Russian Federation)

1994-05-01

47

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

PubMed

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

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

2015-03-01

48

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

SciTech Connect

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.

Ramesh Kumar, V. [Department of Physics, Sri Venkateswara University, Tirupati-517 502 (India); Rao, J.L. [Department of Physics, Sri Venkateswara University, Tirupati-517 502 (India)]. E-mail: jlrao46@yahoo.co.in; Gopal, N.O. [Department of Physics, Sri Venkateswara University, Tirupati-517 502 (India)

2005-08-11

49

Borate Glass Supports the In Vitro Osteogenic Differentiation of Human Mesenchymal Stem Cells  

Microsoft Academic Search

Bioactive ceramics have the ability to bond to surrounding bone and potentially enhance bone in-growth. Silicate based bioactive glasses and glass-ceramics, such as 45S5 bioactive glass, have been widely investigated for bone repair or as scaffolds for cell-based bone tissue engineering. Recent data have demonstrated that silica-free borate glasses also exhibit bioactive behavior and have been shown to convert to

Nicholas W. Marion; Wen Liang; Gwendolen C. Reilly; Delbert E. Day; Mohamed N. Rahaman; Jeremy J. Mao

2005-01-01

50

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

PubMed

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 (250-300?m) 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. PMID:23643606

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

51

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

SciTech Connect

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.

Aziz, Sidek Hj. Abd.; Ahmad, Hamezan; Wahab, Zaidan A.; Sulaiman, Zainal Abidin; Talib, Zainal Abidin; Shaari, A. Halim [Glass Research Laboratory, Faculty of Science, Universiti Putra Malaysia, 43400 UPM Serdang, Selangor (Malaysia); Senin, H. B. [Department of Physical Sciences, Faculty of Science and Technology, University Malaysia Terengganu, 21030 Kuala Terengganu, Terengganu (Malaysia)

2007-05-09

52

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

PubMed

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. PMID:23241965

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

2014-01-01

53

Investigation of the boron-oxygen network in borate glasses by infrared spectroscopy  

Microsoft Academic Search

Lithium borate glasses are fast ionic conductors in which the lithium ions conductivity is all the more important as the content in lithium oxide and in lithium salt is higher. In the perspective of their use as electrolytes in solid state micro-batteries, we have studied the conformation of the boron-oxygen network of lithium halides \\

M. Massot; C. Julien; M. Balkanski

1989-01-01

54

Effects of melt ageing on the density, elastic modulus and glass transition temperature of bismuth borate glasses  

NASA Astrophysics Data System (ADS)

Disc shaped samples of the glass composition: 0.40Bi2O3-0.60B2O3 were prepared by a melt quenching technique by keeping the quenching rate constant but gradually increasing the melt annealing or ageing time from 15 to 220 min at a temperature of 850 °C. A total of five glass samples were prepared. Density, ultrasonic velocity and glass transition temperature measurements showed significant changes in the final glass properties. X-ray fluorescence studies confirmed that the glass composition does not change with the heat treatment of the melt. Our findings challenge the conventional theories of liquids and glass formation which predict that structural changes in a low viscosity melt occur almost instantaneously and a liquid is in its internal equilibrium state above the melting point. We report some unusually slow structural relaxations in bismuth borate glass melts even at elevated temperatures of 850 °C, due to which the melt transforms from a thermodynamically fragile, high density amorphous state to a low density amorphous state which is kinetically stronger. Our findings indicate that bismuth borate melts are metastable liquids and strong candidates for the phenomenon of liquid state polyamorphism.

Khanna, Atul; Sawhney, K. J. S.; Tiwari, M. K.; Bhardwaj, Suresh; Awasthi, A. M.

2003-10-01

55

Structural investigation of bismuth borate glasses under the influence of ?-irradiation through ultrasonic studies  

NASA Astrophysics Data System (ADS)

The ultrasonic velocity and attenuation measurements for different compositions of irradiated heavy metal oxide (HMO) borate glasses xBi 2O 3 (1- x) B 2O 3 (where x=0.25, 0.30, 0.35, 0.40, 0.45) has been investigated at room temperature (303 K) using pulse echo overlap method. The elastic moduli, Debye temperature, Poisson's ratio and other acoustical parameters have been obtained from experimental data. Structural changes after irradiation have been investigated by using FTIR spectroscopy and ultrasonic studies. As the changes are strongly dependent on the internal structure of the absorbing substance, in the present investigation ultrasonic velocities before and after ?-irradiation in bismuth borate glasses are measured as a function of composition, from which the structural changes in the network former B 2O 3 and modifier Bi 2O 3 due to irradiation are obtained.

Sharma, G.; Rajendran, V.; Thind, K. S.; Singh, Gagandeep; Singh, Amarjit

2009-11-01

56

Structure and dissolution investigation of calcium-bismuth-borate glasses and vitroceramics containing silver  

Microsoft Academic Search

Quaternary Ag2O-CaO-Bi2O3-B2O3 glasses and glassceramics are investigated with regard to release behaviour and local structure. The dissolution behaviour\\u000a in water and physiological serum shows that the cations are released rapidly or gradually and points out a multi-step process,\\u000a generally characterised by higher rates in water than in physiological serum. The structural effect of silver addition to\\u000a bismuth-borate glasses is observed

V. Simon; M. Spinu; R. Stefan

2007-01-01

57

Effect of Sm{sub 2}O{sub 3} addition on electrical and optical properties of lithium borate glasses  

SciTech Connect

The electrical and optical property of lithium borate glasses was investigated. It is observed that conductivity decreases while density and refractive index increases with the addition of Sm{sub 2}O{sub 3}. Radiation length of glasses was determined and it is observed that radiation length decreases with the addition of Sm{sub 2}O{sub 3}.

Gedam, R. S.; Ramteke, D. D. [Department of Applied physics, Visvesvaraya National Institute of Technology, Nagpur-440 010 (India)

2012-06-05

58

Role of electron transfer in Ce3+ sensitized Yb3+ luminescence in borate glass  

NASA Astrophysics Data System (ADS)

In a Ce3+-Yb3+ system, two mechanisms are proposed so far namely, the quantum cutting mechanism and the electron transfer mechanism explaining Yb3+ infrared luminescence under Ce3+ excitation. Among them, the quantum cutting mechanism, where one Ce3+ photon (ultraviolet/blue) gives rise to two Yb3+ photons (near infrared) is widely sought for because of its huge potential in enhancing the solar cell efficiency. In present study on Ce3+-Yb3+ codoped borate glasses, Ce3+ sensitized Yb3+ luminescence at ˜1 ?m have been observed on Ce3+ 5d state excitation. However, the intensity of sensitized Yb3+ luminescence is found to be very weak compared to the strong quenching occurred in Ce3+ luminescence in Yb3+ codoped glasses. Moreover, the absolute luminescence quantum yield also showed a decreasing trend with Yb3+ 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 Ce3+-Yb3+ ? Ce4+-Yb2+ 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.

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

2015-01-01

59

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

PubMed

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

Deliormanl?, Aylin M

2015-02-01

60

Conversion of borate-based glass scaffold to hydroxyapatite in a dilute phosphate solution.  

PubMed

Porous scaffolds of a borate-based glass (composition in mol%: 6Na2O, 8K2O, 8MgO, 22CaO, 36B2O3, 18SiO2, 2P2O5), with interconnected porosity of approximately 70% and pores of size 200-500 microm, were prepared by a polymer foam replication technique. The degradation of the scaffolds and conversion to a hydroxyapatite-type material in a 0.02 M K2HPO4 solution (starting pH = 7.0) at 37 degrees C were studied by measuring the weight loss of the scaffolds, as well as the pH and the boron concentration of the solution. X-ray diffraction, scanning electronic microscopy and energy dispersive x-ray analysis showed that a hydroxyapatite-type material was formed on the glass surface within 7 days of immersion in the phosphate solution. Cellular response to the scaffolds was assessed using murine MLO-A5 cells, an osteogenic cell line. Scanning electron microscopy showed that the scaffolds supported cell attachment and proliferation during the 6 day incubation. The results indicate that this borate-based glass could provide a promising degradable scaffold material for bone tissue engineering applications. PMID:20057014

Liu, Xin; Pan, Haobo; Fu, Hailuo; Fu, Qiang; Rahaman, Mohamed N; Huang, Wenhai

2010-02-01

61

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

PubMed

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

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

2015-02-01

62

In vitro bioactivity, cytocompatibility, and antibiotic release profile of gentamicin sulfate-loaded borate bioactive glass/chitosan composites.  

PubMed

Borate bioactive glass-based composites have been attracting interest recently as an osteoconductive carrier material for local antibiotic delivery. In the present study, composites composed of borate bioactive glass particles bonded with a chitosan matrix were prepared and evaluated in vitro as a carrier for gentamicin sulfate. The bioactivity, degradation, drug release profile, and compressive strength of the composite carrier system were studied as a function of immersion time in phosphate-buffered saline at 37 °C. The cytocompatibility of the gentamicin sulfate-loaded composite carrier was evaluated using assays of cell proliferation and alkaline phosphatase activity of osteogenic MC3T3-E1 cells. Sustained release of gentamicin sulfate occurred over ~28 days in PBS, while the bioactive glass converted continuously to hydroxyapatite. The compressive strength of the composite loaded with gentamicin sulfate decreased from the as-fabricated value of 24 ± 3 MPa to ~8 MPa after immersion for 14 days in PBS. Extracts of the soluble ionic products of the borate glass/chitosan composites enhanced the proliferation and alkaline phosphatase activity of MC3T3-E1 cells. These results indicate that the gentamicin sulfate-loaded composite composed of chitosan-bonded borate bioactive glass particles could be useful clinically as an osteoconductive carrier material for treating bone infection. PMID:23820937

Cui, Xu; Gu, Yifei; Li, Le; Wang, Hui; Xie, Zhongping; Luo, Shihua; Zhou, Nai; Huang, Wenhai; Rahaman, Mohamed N

2013-10-01

63

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

NASA Astrophysics Data System (ADS)

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.

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

2004-05-01

64

Gentamicin-loaded borate bioactive glass eradicates osteomyelitis due to Escherichia coli in a rabbit model.  

PubMed

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

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

2013-07-01

65

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

PubMed Central

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

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

2013-01-01

66

Carbon nanotube-doped tellurite glasses  

NASA Astrophysics Data System (ADS)

In the past it was observed that buck ball doped glasses showed enhanced optical nonlinearities. However, carbon nanotubes are much more stable than buck ball and should be a better choice for that purpose. Therefore we decided to investigate the possibility to produce carbon nanotubes doped tellurite glasses and measured their optical nonlinearities. Tellurite glasses already have a larger nonlinearity compared to silica, and other, glasses. We produced TeO II-ZnO tellurite family glasses doped with multi wall Carbon Nanotube (CNT). The CNTs acquired from Carbolex were vigorously mechanically mixed with the tellurite glass precursors and melted in platinum crucible around 650°C in a controlled atmosphere inside an electrical induction furnace. We used the lowest temperature possible and controlled atmosphere to avoid the CNT oxidation. The glass melt was cast in a stainless steel and thermally treated at 300°C for 5 hours to relieve internal stresses. The samples were than cutted and polished to perform the optical characterization. We measured refractive index and thermo physical properties, such as vitreous transition T g, crystallization onset T x and melting T f temperatures. Raman spectroscopy showed the possible presence of CNTs.

Mazali, I. O.; Chillcce, E. F.; Ferreira, O. P.; Rodriguez, E.; Jacob, G. J.; Cesar, C. L.; Barbosa, L. C.

2008-02-01

67

Complex Heat Capacity of Lithium Borate Glasses Studied by Modulated DSC  

SciTech Connect

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.

Matsuda, Yu; Ike, Yuji [Graduate School of Pure and Applied Sciences, University of Tsukuba, Tsukuba, Ibaraki, 305-8571 (Japan); Matsui, Chihiro [College of Engineering Sciences, University of Tsukuba, Tsukuba, Ibaraki, 305-8573 (Japan); Kodama, Masao [Department of Applied Chemistry, Sojo University, Kumamoto, 860-0082 (Japan); Kojima, Seiji [Graduate School of Pure and Applied Sciences, University of Tsukuba, Tsukuba, Ibaraki, 305-8571 (Japan); College of Engineering Sciences, University of Tsukuba, Tsukuba, Ibaraki, 305-8573 (Japan)

2006-05-05

68

Niobium phosphate glasses doped with rare earths  

NASA Astrophysics Data System (ADS)

Er- and Sm-doped sodium-niobium phosphate glasses have been produced by melting technique. Their optical and spectroscopic properties have been fully characterized. Fluorescence lifetimes of the metastable states of Er3+ and Sm3+ ions are long enough to make these glasses suitable to be used in optical amplification devices. Waveguides have been produced by diluted Ag+/Na+ ion exchange and their properties are also described.

Chen, B. J.; Brenci, Massimo; Pelli, Stefano; Righini, Giancarlo C.; Lipovskii, Andrey A.; Tagantsev, Dmitrii K.

2003-11-01

69

A novel injectable borate bioactive glass cement for local delivery of vancomycin to cure osteomyelitis and regenerate bone.  

PubMed

Osteomyelitis (bone infection) is often difficult to cure. The commonly-used treatment of surgical debridement to remove the infected bone combined with prolonged systemic and local antibiotic treatment has limitations. In the present study, an injectable borate bioactive glass cement was developed as a carrier for the antibiotic vancomycin, characterized in vitro, and evaluated for its capacity to cure osteomyelitis in a rabbit tibial model. The cement (initial setting time = 5.8 ± 0.6 min; compressive strength = 25.6 ± 0.3 MPa) released vancomycin over ~25 days in phosphate-buffered saline, during which time the borate glass converted to hydroxyapatite (HA). When implanted in rabbit tibial defects infected with methicillin-resistant Staphylococcus aureus (MRSA)-induced osteomyelitis, the vancomycin-loaded cement converted to HA and supported new bone formation in the defects within 8 weeks. Osteomyelitis was cured in 87 % of the defects implanted with the vancomycin-loaded borate glass cement, compared to 71 % for the defects implanted with vancomycin-loaded calcium sulfate cement. The injectable borate bioactive glass cement developed in this study is a promising treatment for curing osteomyelitis and for regenerating bone in the defects following cure of the infection. PMID:24477872

Cui, Xu; Zhao, Cunju; Gu, Yifei; Li, Le; Wang, Hui; Huang, Wenhai; Zhou, Nai; Wang, Deping; Zhu, Yi; Xu, Jun; Luo, Shihua; Zhang, Changqing; Rahaman, Mohamed N

2014-03-01

70

Photoreversible birefringence in doped Vycor glass  

NASA Astrophysics Data System (ADS)

Photoreversible birefringence is demonstrated in Vycor glass, doped with nanocrystalline ZnS and Cu, by linearly polarized 266-nm pulsed excitation. The birefringence is readily reversed by exposure to orthogonally polarized UV radiation. Photoinduced birefringence is stable at room temperature and can be removed by annealing at temperatures above 250 degC.

Huston, A. L.; Justus, B. L.

1995-05-01

71

The Development of Doped Radiosensitive Glass  

SciTech Connect

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.

Bradley, D. A.; Okoya, O. O. [Department of Physics, University of Surrey, Guildford, GU2 7XH (United Kingdom); Hugtenburg, R. P. [School of Physics and Astronomy, University of Birmingham, B15 2TT (United Kingdom); Queen Elizabeth Medical Centre, University Hospital Birmingham NHS Trust, B15 2TH (United Kingdom); Hashim, Suhairul; Ramli, A. T.; Wagiran, H. [Department of Physics, Universiti Teknologi Malaysia, 81310 Skudai, Johor Darul Takzim (Malaysia); Yusoff, A. L. [Department of Nuclear Medicine, Radiotherapy and Oncology, School of Medical Sciences, Universiti Sains Malaysia, 16150 Kubang Kerian (Malaysia); Hassan, A. Aziz Mat [Telekom Research and Development Sdn. Bhd., Idea Tower, Incubation Center, UPM-MTDC, Lebuh Silikon, UPM, 43400 Serdang, Selangor Darul Ehsan (Malaysia)

2007-05-09

72

Transition element-doped crystals in glass  

NASA Astrophysics Data System (ADS)

Transition metals are well known as optically active dopants in crystalline hosts because they fluoresce broadly in the near-IR; examples include Ti3+:sapphire (Al2O3) and Cr4+:forsterite (Mg2SiO4). Because transition element ions yield stronger optical activity with those of doped crystal. The glass-ceramic process can, in many cases, also allow the growth in glass of crystals which are difficult or impossible to obtain in single crystal form. Material properties and spectroscopic data are presented for transparent glass-ceramics based on transition element-doped forsterite, willemite, mixed Li-Zn-Mg- orthosilicates, and spinel crystals. The transition element ions include Cr4+ in tetrahedral coordination and Ni2+ in octahedral coordination. The optical property measurements of the transparent glass-ceramics, including absorbance, fluorescence, and fluorescence lifetimes, duplicate those reported in the literature for single crystal or powders. Cr4+- and Ni2+-doped glass-ceramics exhibit broad emission across the telecommunications wavelength range of 1100-1700 nm.

Pinckney, Linda R.; Beall, George H.

2001-11-01

73

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

NASA Technical Reports Server (NTRS)

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.

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

1985-01-01

74

Femtosecond laser induced coordination transformation and migration of ions in sodium borate glasses  

SciTech Connect

We report on the coordination transformation of B{sup 3+} ions and migration of Na{sup +} and O{sup 2-} ions in sodium borate glasses, induced by 250 kHz, 800 nm femtosecond laser irradiation. Micro-Raman spectra show that the ratio of the integrated intensity of the two peaks at 806 and 774 cm{sup -1} decreases at first and then increases with increasing distance from the center of the laser modified zone. Electron dispersive x-ray spectra show that a portion of Na{sup +} and O{sup 2-} ions migrate from the vicinity of focal point after the femtosecond laser irradiation. A possible mechanism is proposed to explain the observed phenomena.

Liu Yin; Zhu Bin; Wang Li; Qiu Jianrong [State Key Laboratory of Silicon Materials, Zhejiang University, Hangzhou 310027 (China); Dai Ye; Ma Hongliang [Department of Physics, Shanghai University, Shanghai 200444 (China)

2008-03-24

75

New high capacity cathode materials for rechargeable Li-ion batteries: vanadate-borate glasses.  

PubMed

V2O5 based materials are attractive cathode alternatives due to the many oxidation state switches of vanadium bringing about a high theoretical specific capacity. However, significant capacity losses are eminent for crystalline V2O5 phases related to the irreversible phase transformations and/or vanadium dissolution starting from the first discharge cycle. These problems can be circumvented if amorphous or glassy vanadium oxide phases are employed. Here, we demonstrate vanadate-borate glasses as high capacity cathode materials for rechargeable Li-ion batteries for the first time. The composite electrodes of V2O5 - LiBO(2) glass with reduced graphite oxide (RGO) deliver specific energies around 1000 Wh/kg and retain high specific capacities in the range of ~ 300 mAh/g for the first 100 cycles. V2O5 - LiBO(2) glasses are considered as promising cathode materials for rechargeable Li-ion batteries fabricated through rather simple and cost-efficient methods. PMID:25408200

Afyon, Semih; Krumeich, Frank; Mensing, Christian; Borgschulte, Andreas; Nesper, Reinhard

2014-01-01

76

New High Capacity Cathode Materials for Rechargeable Li-ion Batteries: Vanadate-Borate Glasses  

NASA Astrophysics Data System (ADS)

V2O5 based materials are attractive cathode alternatives due to the many oxidation state switches of vanadium bringing about a high theoretical specific capacity. However, significant capacity losses are eminent for crystalline V2O5 phases related to the irreversible phase transformations and/or vanadium dissolution starting from the first discharge cycle. These problems can be circumvented if amorphous or glassy vanadium oxide phases are employed. Here, we demonstrate vanadate-borate glasses as high capacity cathode materials for rechargeable Li-ion batteries for the first time. The composite electrodes of V2O5 - LiBO2 glass with reduced graphite oxide (RGO) deliver specific energies around 1000 Wh/kg and retain high specific capacities in the range of ~ 300 mAh/g for the first 100 cycles. V2O5 - LiBO2 glasses are considered as promising cathode materials for rechargeable Li-ion batteries fabricated through rather simple and cost-efficient methods.

Afyon, Semih; Krumeich, Frank; Mensing, Christian; Borgschulte, Andreas; Nesper, Reinhard

2014-11-01

77

Bioactive borate glass scaffolds: in vitro and in vivo evaluation for use as a drug delivery system in the treatment of bone infection  

Microsoft Academic Search

The objective of this work was to evaluate borate bioactive glass scaffolds (with a composition in the system Na2O–K2O–MgO–CaO–B2O3–P2O5) as devices for the release of the drug Vancomycin in the treatment of bone infection. A solution of ammonium phosphate,\\u000a with or without dissolved Vancomycin, was used to bond borate glass particles into the shape of pellets. The in vitro degradation

Xin Liu; Zongping Xie; Changqing Zhang; Haobo Pan; Mohamed N. Rahaman; Xin Zhang; Qiang Fu; Wenhai Huang

2010-01-01

78

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

SciTech Connect

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.

Borodi, G. [National Institute for Research and Development of Isotopic and Molecular Technologies, 65-103 Donath, 400293 Cluj-Napoca (Romania)] [National Institute for Research and Development of Isotopic and Molecular Technologies, 65-103 Donath, 400293 Cluj-Napoca (Romania); Pascuta, P.; Bosca, M.; Pop, V. [Technical University, 28 Memorandumului, 400114 Cluj-Napoca (Romania)] [Technical University, 28 Memorandumului, 400114 Cluj-Napoca (Romania); Stefan, R. [Agricultural Science and Veterinary Medicine University, 3-5 Calea Manastur, 400372 Cluj-Napoca (Romania)] [Agricultural Science and Veterinary Medicine University, 3-5 Calea Manastur, 400372 Cluj-Napoca (Romania); Tetean, R. [Babes-Bolyai University, 1 Mihail Kogalniceanu, Faculty of Physics, 400084 Cluj Napoca (Romania)] [Babes-Bolyai University, 1 Mihail Kogalniceanu, Faculty of Physics, 400084 Cluj Napoca (Romania); Radulescu, D. [University of Medicine and Pharmacy Iuliu Hatieganu, 8 Victor Babes, 400012 Cluj-Napoca (Romania)] [University of Medicine and Pharmacy Iuliu Hatieganu, 8 Victor Babes, 400012 Cluj-Napoca (Romania)

2013-11-13

79

Properties and applications of doped chalcogenide glasses  

NASA Astrophysics Data System (ADS)

The effect of low amounts of antimony, tin, dysprosium, samarium and manganese on structure and optical properties of chalcogenide glassy semiconductors As2S3 and As2Se3 is investigated. The fundamental absorption edge shifts to longer wavelength with doping; the largest shift was observed for doped chalcogenide glasses. Near the edge absorption the impurity affects strongly the slope and the magnitude of the weak absorption tail. The steady-state and transient photoconductivity characteristics are adequately interpreted in frame of the model, in which transport and recombination of non-equilibrium holes are controlled by exponentially distributed hole traps with the distribution parameter T*, depending on the glass composition. Some application of amorphous chalcogenide thin film structures as registration media are presented.

Iovu, Mihai S.

2003-10-01

80

Thermoluminescence properties of CaO-B2O3 glass system doped with GeO2  

NASA Astrophysics Data System (ADS)

The aim of this study is to investigate the thermoluminescence properties of germanium doped calcium borate glass for thermoluminescence dosimeter used. Glasses with composition (30-x) CaO-70B2O3: xGeO2 where x=0.1, 0.2, 0.3, 0.4 and 0.5 mol% were prepared using a melt-quenching method. The glasses were irradiated to 60Co gamma ray with doses ranging from 0.5 Gy to 4.0 Gy. The amorphous phases were identified for all glass samples. The glow curves were analyzed to determine various characterizations of a thermoluminescence dosimeter of the glass. It was found that the sample with a concentration of 0.1 mol% GeO2 has the best thermoluminescence characteristics such as linearity, sensitivity, fading characteristic, minimum detectable dose and effective atomic number. The results clearly showed that germanium doped calcium borate glass has a potential to be considered as the thermoluminescence dosimeter.

Tengku Kamarul Bahri, T. N. H.; Wagiran, H.; Hussin, R.; Hossain, I.; Kadni, T.

2014-09-01

81

Characterisation of Erbium Doped Phosphate Glass  

SciTech Connect

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 Na{sub 2}O. The emission spectra from luminescence spectroscopy resolved six emission peaks from the excitation wavelength of 336.8 nm (3.69 eV). The emission of {sup 4}F{sub 7/2} 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.

Rasid, A. A.; Rohani, M. S.; Sahar, M. R.; Kasim, A. [Advanced Optical Material Research Group, Physics Dept., Faculty of Science, Universiti Teknologi Malaysia, 81310 UTM Skudai, Johor (Malaysia)

2010-03-11

82

Co-doped Barium Phosphate Glass  

NASA Astrophysics Data System (ADS)

Co-doping of a P2O5:BaO glass matrix with divalent tin and trivalent samarium ions has been realized by the melt-quenching technique with the purpose of investigating the material's luminescent properties. Photoluminescence excitation spectra obtained by monitoring Sm3+ 4G5/2 emission showed a broad excitation band around 290 nm (absent in a Sm3+-doped reference), typical of donor/acceptor energy transfer. Under such excitation, the material exhibits a reddish-white emission. Time-resolved spectra recorded under the 290-nm excitation (non-resonant with Sm3+ excitation peaks) exposed a broad blue-white band characteristic of twofold-coordinated Sn centers and orange-red emission bands of Sm3+ ions, which appeared well separated in time in accord with their emission decay dynamics. Consequently, the data indicate that light absorption occurs at Sn centers (donors) followed by energy transfer to samarium ions (acceptors) which results in populating the 4G5/2 emitting state in Sm3+. Energy transfer pathways likely resulting in the sensitization of Sm3+ photoluminescence are discussed. Results are put into context in terms of the potential of SnO and rare-earth co-doped barium phosphate glasses for use in white light-emitting devices.

Jiménez, J. A.

2014-09-01

83

Transport properties of AgI doped silver molybdate superionic glass-nanocomposites  

NASA Astrophysics Data System (ADS)

We have reported the dc conductivity as well as the ac conductivity in the frequency range 10 Hz-2 MHz for xAgI-(1- x)(0.5Ag2O-0.5MoO3), glass-nanocomposites in the temperature range 100-303 K. We have compared the conductivity and its activation energy for the molybdate nanocomposites with those of the borate and phosphate glasses. We have analysed the ac conductivity using the power law model. We have observed that both the dc conductivity and the crossover frequency obtained from the power law model show an activated behaviour. We have also observed that the power law exponent is almost independent of AgI doping content. Furthermore, the concentration of the mobile Ag+ ions is found to be independent of temperature as well as the AgI content in the compositions.

Bhattacharya, S.; Ghosh, A.

2005-09-01

84

LITHIUM-7, BORON-10, BORON-11, and OXYGEN-17 Nuclear Magnetic Resonance Studies of Lithium Borate Glasses and Related Compounds.  

NASA Astrophysics Data System (ADS)

Nuclear Magnetic Resonance (NMR) studies of lithium borate glasses employing the two stable isotopes of boron, B('10) and B('11), were used in the formulation of a consistent structural model throughout the glass-forming region. The ideas of Krogh-Moe were used in which the glasses are viewed as mixtures of units found in corresponding crystalline compounds. For low-alkali oxide content glasses the results are in good agreement with those obtained by Jellison and Bray in sodium borate glasses. These glasses are viewed as being mixtures of boroxol, tetraborate and diborate units. Intermediate-alkali oxide content glasses satisfy a model proposed in this thesis in which diborate and tetraborate units are destroyed to form loose N('4) and metaborate units. For high-alkali oxide content glasses the results are in good agreement with a model proposed by Yun and Yun and Bray in which loose N('4), metaborate, pyroborate and orthoborate units exist. Li(,2)O, enriched in O('17), was synthesized in such a way that H(,2)O enriched to 54% O('17) was efficiently transferred into Li(,2)O. It is hypothesized that the synthesis of Li(,2)O enriched in O('17) as well as the synthesis of the other alkali oxides (e.g. Na(,2)O, K(,2)O, Rb(,2)O and Cs(,2)O) will greatly enlarge the range of O('17) NMR studies of glasses and related compounds. Li('7) and O('17) NMR studies of Li(,2)O revealed structureless derivative spectra of linewidths 9.9 gauss and 5.8 gauss, respectively. These experimental results were compared to a second-moment calculation of the linewidths using the anti-fluorite crystal structure for Li(,2)O. O('17) NMR studies of two lithium borate compounds, lithium metaborate (Li(,2)O(.)B(,2)O(,3)) and lithium orthoborate (3Li(,2)O(.)B(,2)O(,3)) were used to identify the quadrupole parameters of bridging and non-bridging oxygen atoms. These results, in conjunction with B('11) NMR results from these compounds, were used to determine charge densities associated with the boron and oxygen atoms by means of the simplifying approximations of Townes and Dailey.

Feller, Steven Allen

1980-06-01

85

Comparative study of lead borate and bismuth lead borate glass systems as gamma-radiation shielding materials  

Microsoft Academic Search

Gamma-ray mass attenuation coefficients have been measured experimentally and calculated theoretically for PbO–B2O3 and Bi2O3–PbO–B2O3 glass systems using narrow beam transmission method. These values have been used to calculate half value layer (HVL) parameter. These parameters have also been calculated theoretically for some standard radiation shielding concretes at same energies. Effect of replacing lead by bismuth has been analyzed in

Narveer Singh; Kanwar Jit Singh; Kulwant Singh; Harvinder Singh

2004-01-01

86

Characterization of new erbium-doped tellurite glasses and fibers  

E-print Network

Characterization of new erbium-doped tellurite glasses and fibers S. Marjanovic a,*, J. Toulouse of their excellent optical and chemical properties. The emission spectrum from erbium in tellurite glasses is almost on the microscopic structure of these glasses, and a study of the erbium emission in fibers fabricated from

Dierolf, Volkmar

87

Scintillating luminescence of cerium-doped dense oxide glass  

NASA Astrophysics Data System (ADS)

New dense oxide glass scintillator has been discovered in the system: B2O3-SiO2-Al2O3- Gd2O3 doped with trivalence cerium. This scintillator has a unique combination of properties including high scintillating light output, high density and desirable emission wavelength, large radiation hardness, short radiation length, and easy to produce in large size and low price. Here we compare the properties with those of the two recently developed dense scintillators: Ce3+-doped fluorophosphate glass and Ce3+-doped fluorohafnate glass, and with those of the three most widely used scintillating crystals Ce:YAP,CeF3 and BGO.

Jiang, Chun; Zhang, Junzhou; Gan, Fuxi

1999-10-01

88

Sm3+ doped lithium aluminoborate glasses for orange coloured visible laser host material  

NASA Astrophysics Data System (ADS)

Samarium doped lithium aluminium borate glasses have been prepared by conventional melt quench technique and their detailed spectroscopic analysis has been done. The structural analysis has been done by using FTIR studies and density is measured by Archimedes method. The UV-vis-NIR absorption spectra show an increase in intensity of different transitions from the ground level 6H5/2 to various 2S+1LJ levels with an increase in samarium concentration at the expense of aluminium. The fluorescence spectra show several transitions from 4G5/2 to various 6HJ levels along with 4F3/2 to 6HJ and 4G7/2 to 6H5/2.

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

2013-10-01

89

Surface characterization of silver-doped bioactive glass.  

PubMed

A bioactive glass belonging to the system SiO(2)-CaO-Na(2)O was doped with silver ions by ion exchange in molten salts as well as in aqueous solution. The ion exchange in the solution was done to check if it is possible to prepare an antimicrobial material using a low silver content. The doped glass was characterized by means of X-ray diffraction, SEM observation, EDS analysis, bioactivity test (soaking in a simulated body fluid), leaching test (GFAAS analyses) and cytotoxicity test. It is demonstrated that these surface silver-doped glasses maintain, or even improve, the bioactivity of the starting glass. The measured quantity of released silver into simulated body fluid compares those reported in literature for the antibacterial activity and the non-cytotoxic effect of silver. Cytotoxicity tests were carried out to understand the effect of the doped surfaces on osteogenic cell adhesion and proliferation. PMID:15792537

Vernè, E; Di Nunzio, S; Bosetti, M; Appendino, P; Brovarone, C Vitale; Maina, G; Cannas, M

2005-09-01

90

Relaxation dynamics in AgI-doped silver vanadate superionic glasses.  

PubMed

Relaxation dynamics of Ag+ ions in several series of AgI-Ag2O-V2O5 superionic glasses has been studied in the frequency range from 10 Hz to 2 MHz and in the temperature range from 93 to 323 K. 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. The frequency-dependent electrical data have been analyzed in the framework of conductivity formalism. We have obtained the mobile ion concentration and the power-law exponent from the analysis of the conductivity spectra. We have observed that the concentration of Ag+ ions is independent of temperature and the conductivity is primarily determined by the mobility. A fraction of the Ag+ ions in the glass compositions are involved in the dynamic process. We have also shown that the power-law exponent is independent of temperature. The results are also supported by the temperature and composition independence of the scaling of the conductivity spectra. PMID:16392504

Bhattacharya, S; Ghosh, A

2005-09-22

91

Relaxation dynamics in AgI-doped silver vanadate superionic glasses  

NASA Astrophysics Data System (ADS)

Relaxation dynamics of Ag+ ions in several series of AgI-Ag2O-V2O5 superionic glasses has been studied in the frequency range from 10Hzto2MHz and in the temperature range from 93to323K. 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. The frequency-dependent electrical data have been analyzed in the framework of conductivity formalism. We have obtained the mobile ion concentration and the power-law exponent from the analysis of the conductivity spectra. We have observed that the concentration of Ag+ ions is independent of temperature and the conductivity is primarily determined by the mobility. A fraction of the Ag+ ions in the glass compositions are involved in the dynamic process. We have also shown that the power-law exponent is independent of temperature. The results are also supported by the temperature and composition independence of the scaling of the conductivity spectra.

Bhattacharya, S.; Ghosh, A.

2005-09-01

92

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

NASA Astrophysics Data System (ADS)

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 (?) values indicate that, the metal-ligand environment in the prepared glasses is of ionic in nature. The oscillator strength and the luminescent intensity ?? (? = 2, 4 and 6) parameters are calculated using Judd-Ofelt theory. The radiative properties such as transition probability (A), stimulated emission cross-section (?pE) and branching ratios (?) 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 ?pE, ?R, ?pE×?pE, ?pE×??eff and ? values for the 6H13/2 emission band which in turn specifies its suitability for white LEDs, laser applications and optical amplifiers.

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

2014-11-01

93

Photoinduced phenomena in chalcogenide glasses doped with metals  

E-print Network

on relaxation of photodarkening in a-As2Se3 doped with Sn and rare-earth (RE) ions (Dy, Pr, Hon, Sm3 Nd, Er3 for chalcogenide glasses doped with rare-earth ions as perspective materials for fibre optics amplifiers operating and the kinetics ofphotodarkening in amonhous As2Se3:Sn thin films at %) and and AsSe3 doped with rare-earth ions

Boolchand, Punit

94

EPR study of coordination of Ag and Pb cations in BaB2O4 crystals and barium borate glasses  

Microsoft Academic Search

It is shown the possibility to determine the coordination of paramagnetic ions in disordered solid structures, e.g., in barium borate glasses. For this purpose the electron paramagnetic resonance (EPR) method was used to study alpha-and beta-BaB2O4 crystals and glasses of 45·BaO × 55·B2O3 and 40·BaO × 60·B2O3 (mol%) composition activated by Ag+ and Pb2+ ions. After the samples were exposed

V. P. Solntsev; R. I. Mashkovtsev; A. V. Davydov; E. G. Tsvetkov

2008-01-01

95

Broadband optical amplification in Bi-doped germanium silicate glass  

NASA Astrophysics Data System (ADS)

Bi-doped germanium silicate glass is prepared and their optical properties are investigated. The glass sample shows broadband and flat emission characteristics compared with germanate glass. The single-pass optical amplification was measured on a traditional two-wave mixing configuration. Ultrabroadband optical amplification at 1272 and 1560nm is observed simultaneously. The highest gain at 1272nm of germanium silicate glass reaches to 6.73dB excited with single commercially available 980nm laser diode. The glass is promising for optical amplification covering almost all the O, E, S, C, and L bands.

Zhou, Shifeng; Dong, Huafang; Zeng, Heping; Feng, Gaofeng; Yang, Hucheng; Zhu, Bin; Qiu, Jianrong

2007-08-01

96

Structural studies of some phospho-borate glasses using ultrasonic pulse-echo technique, DSC and IR spectroscopy  

NASA Astrophysics Data System (ADS)

Glasses in the system (95- x) [0.25 Na 2O-0.75 B 2O 3]- x P 2O 5-5 Fe 2O 3 (0? x?15 mol%), have been prepared by the melt quenching technique. Elastic properties and FT-IR spectroscopic studies have been employed to study the role of P 2O 5 on the structure of the glass system. Elastic properties Poisson's ratio, micro-hardness and Debye temperature have been investigated using sound wave velocity measurements at 4 MHz (both longitudinal and shear) at room temperature. The results showed that the density and the molar volume increase as both sound velocities and the determined glass transition temperatures decrease with increasing the contents of P 2O 5. Infrared spectra of the glasses reveal that the borate network consists of diborate units and is affected by the increase in the concentration of P 2O 5 content as a second network former. These results are interpreted in terms of the replacement of the diborate units with B-O-B bridges by phosphate units with non-bridging oxygens (NBOs). Therefore, the elastic moduli are observed to decrease with the increase in P 2O 5 content.

Gaafar, M. S.; Afifi, H. A.; Mekawy, M. M.

2009-06-01

97

[Spectroscopic properties of Er3+-doped germanium bismuthate glass].  

PubMed

Er(3+)-Doped Germanium Bismuthate Glass was fabricated and characterized. The absorption spectrum and up-conversion spectrum of glass were studied. The Judd-Oflet intensity parameters omega(t) (t = 2, 4, 6), determined based on Judd-Ofelt theory, were found to be omega2 = 3.35 x 10(-20) cm2, omega4 = 1.34 x 10(-20) cm2, omega6 = 0.67 x 10(-20) cm2. Frequency up-conversion of Er(3+)-doped germanium bismuthate glass has been investigated. The up-conversion mechanisms are discussed under 808 nm and 980 nm excitation. Stimulated emission cross-section of 4I(13/2) --> 4I(15/2) transition was calculated by McCumber theory. Compared to other host glasses, the emission property of Er(3+)-doped germanium bismuthate glasses has advantage over those of silicate, phosphate and germinate glasses. Er(3+)-doped germanium bismuth glasses are promising upconversion optical and optic-communication materials. PMID:18720787

Zhang, Yong; Ren, Guo-Zhong; Yang, Qi-Bin; Xu, Chang-Fu; Liu, Yun-Xin; Shang, Zhen-Gang

2008-05-01

98

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

NASA Astrophysics Data System (ADS)

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 (?) and bonding parameter (?) 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 (?2, ?4 and ?6) were calculated with the application of JO theory and the trends of the JO intensity parameters are found to be ?2 > ?6 > ?4 for all the prepared glasses with a minimum variation in ?2 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 (?PE), branching ratio (?r) and radiative lifetime (?) 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.

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

2015-01-01

99

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

PubMed

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 (?) and bonding parameter (?) 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 (?2, ?4 and ?6) were calculated with the application of JO theory and the trends of the JO intensity parameters are found to be ?2>?6>?4 for all the prepared glasses with a minimum variation in ?2 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 (?P(E)), branching ratio (?r) and radiative lifetime (?) 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. PMID:25173526

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

2015-01-25

100

Bismuth-doped Mg — Al silicate glasses and fibres  

NASA Astrophysics Data System (ADS)

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 ?m.

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.

2012-09-01

101

Bi-doped glasses for broadband fiber light source  

NASA Astrophysics Data System (ADS)

Bi-doped silica glass is a new broadband infrared fluorescence material. We drew optical fibers with the Bi doped silica glass for the fiber core and evaluated the fluorescence spectrum. The FWHM of fluorescence spectrum is measured to be 390 nm. When this broad band spectrum is used as an OCT light source, the expected axial resolution is calculated to be 1.9?m, This is comparable to the axial resolution (?z~1?m) by Ti:Al2O3 system. And we also examined the local structure of Bi ion in Bi-doped silica glass. These are analyzed by ESR, EXAFS, XPS, and 27Al-NMR. According to these results, the structural model of Bi luminescent center is proposed that Bi5+ ion with 6-fold coordination exists close to Al3+ ion with 6-fold coordination.

Fujimoto, Yasushi

2009-02-01

102

Fast Ion Conduction of Copper Iodide Doped Chalcogenide Glasses  

NASA Astrophysics Data System (ADS)

Electrical conductivity, Raman and extended X-ray absorption fine structure (EAXFS) measurements have been performed for CuI-doped As2Se3 chalcogenide glasses over a wide composition range up to 70 mol% CuI. The addition of CuI into As2Se3 glass is responsible for a pronounced increase in the electrical conductivity. The ionic component of the electrical conductivity is dominant in highly CuI-doped glasses. Results of Raman spectra and detailed structural analysis for the EXAFS functions suggest that the local structure of the present glasses can be described as a mixture of AsSe3/2 network matrix and CuI-related conduction pathways.

Usuki, T.; Furukawa, T.; Kanai, K.; Nasu, T.

2013-07-01

103

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

SciTech Connect

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 ?{sub 2}, ?{sub 4} and ?{sub 6} parameters. Radiative properties like branching ratio ?{sub r} and the radiative life time ?{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+}.

Goud, K. Krishna Murthy, E-mail: krishnamurthy.phy@gmail.com; Reddy, M. Chandra Shekhar, E-mail: krishnamurthy.phy@gmail.com; Rao, B. Appa, E-mail: krishnamurthy.phy@gmail.com [Dept. of Physics, Osmania University, Hyderabad-500007, Andhra Pradesh (India)

2014-04-24

104

Structural and optical properties of barium titanate modified bismuth borate glasses  

NASA Astrophysics Data System (ADS)

Glass samples with composition (70B2O3-29Bi2O3-1Dy2O3) modified with Barium titanate (BT), where BT is added in different successive weight percents, have been synthesized by conventional melt quenching technique. X-ray diffraction studies were performed in order to confirm the amorphous nature of the samples. The density of the samples has been found to decrease with an increase in the BT content, whereas an opposite trend has been observed in the molar volume. The analysis of FTIR and Raman spectra of the samples depicts that the glass network is built up of mainly BiO6, BiO3, BO3 and BO4 units. Its detailed analysis also revealed that the glass structure depends upon the amount of BT in the glass matrix and hence it acts as a modifier in the glass network. Introduction of BT into the glass matrix leads to the conversion of BO3 trigonal units into BO4 tetrahedral units, which results in a decrease in the degree of disorder in the glass network and makes the glass system more stable. The values of Urbach energy obtained for the prepared samples also confirmed the decrease in disorder in the glass network. The optical absorption measurements carried out for well-polished samples show a decrease in optical band gap energy with an increase in BT content whereas the molar refractivity shows the reverse trend. The Hydrogenic excitonic model applied to the studied glasses suggested that the present glass system favors direct transitions. The metallization criterion of the presently studied samples suggests that the prepared glasses may be potential candidates for nonlinear optical applications.

Singh, Lakhwant; Thakur, Vanita; Punia, R.; Kundu, R. S.; Singh, Anupinder

2014-11-01

105

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

SciTech Connect

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.

Appleby, G. A.; Edgar, A.; Williams, G. V. M.; Bos, A. J. J. [MacDiarmid Institute, Victoria University of Wellington, P.O. Box 600, Wellington (New Zealand); Industrial Research Limited, Wellington (New Zealand) and MacDiarmid Institute, Victoria University of Wellington, P.O. Box 600 Wellington (New Zealand); Faculty of Applied Sciences, Delft University of Technology, 2629 JB Delft (Netherlands)

2006-09-04

106

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

NASA Astrophysics Data System (ADS)

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 ?2>?4>?6 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.

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

2015-01-01

107

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

SciTech Connect

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 studies.

Edelman, I.; Ivanova, O.; Ivantsov, R.; Velikanov, D.; Zabluda, V. [L.V. Kirensky Institute of Physics SB RAS, 660036 Krasnoyarsk (Russian Federation); Zubavichus, Y.; Veligzhanin, A. [NRC 'Kurchatov Institute,' 123182 Moscow (Russian Federation); Zaikovskiy, V. [Boreskov Institute of Catalysis, Siberian Branch of RAS, 630090 Novosibirsk (Russian Federation); Stepanov, S. [S.I. Vavilov State Optical Institute, St. Petersburg (Russian Federation); Artemenko, A. [ICMCB, UPR CNRS 9048, 33608 Pessac cedex (France); Curely, J.; Kliava, J. [LOMA, UMR 5798 Universite Bordeaux 1-CNRS, 33405 Talence cedex (France)

2012-10-15

108

Compact, highly efficient ytterbium doped bismuthate glass waveguide laser.  

PubMed

Laser slope efficiencies close to the quantum defect limit and in excess of 78% have been obtained from an ultrafast laser inscribed buried channel waveguide fabricated in a ytterbium-doped bismuthate glass. The simultaneous achievement of low propagation losses and preservation of the fluorescence properties of ytterbium ions is the basis of the outstanding laser performance. PMID:22627539

Mary, R; Beecher, S J; Brown, G; Thomson, R R; Jaque, D; Ohara, S; Kar, A K

2012-05-15

109

XANES studies on Eu-doped fluorozirconate based glass ceramics  

PubMed Central

The influence of adding InF3 as a reducing agent on the oxidation state of Eu in fluorochloro- (FCZ) and fluorobromozirconate (FBZ) glass ceramics was investigated using x-ray absorption near edge (XANES) and photoluminescence (PL) spectroscopy. For both materials, it was found that InF3 decreases the Eu2+-to-Eu3+ ratio significantly. PL spectroscopy proved that an annealing step leads to the formation of Eu-doped BaCl2 and BaBr2 nanocrystals in the FCZ and FBZ glasses, respectively. In the case of FCZ glass ceramics the hexagonal phase of BaCl2 could be detected in indium-free and InF3-doped ceramics, but only for InF3 containing FCZ glass ceramics a phase transition of the nanoparticles from hexagonal to orthorhombic structure is observed. For the FBZ glass ceramics, the hexagonal phase of BaBr2 can be formed with and without indium doping, but only in the indium-free case a phase transition to orthorhombic BaBr2 could be found. PMID:24748708

Henke, Bastian; Keil, Patrick; Paßlick, Christian; Vogel, Dirk; Rohwerder, Michael; Wiegand, Marie-Christin; Johnson, Jacqueline A.; Schweizer, Stefan

2012-01-01

110

Impedance spectroscopic characterization of Sm2O3 containing lithium borate glasses  

NASA Astrophysics Data System (ADS)

27.5 Li2O-(72.5-X) B2O3-X Sm2O3 (X = 0.5, 1, 1.5 and 2) were prepared by conventional melt quench technique. Impedance spectroscopy (IS) is used to study the electrical properties of these prepared glasses. Modulus formalism is introduced to study relaxation behaviour of these glasses. Scaling model shows the good overlap of data on single master curve which suggests that conduction mechanism in these glasses is compositional dependent. Variation of dielectric constant and dielectric loss with the addition of Sm2O3 and frequency are discussed here.

Ramteke, D. D.; Gedam, R. S.

2014-12-01

111

EPR study of coordination of Ag and Pb cations in BaB 2 O 4 crystals and barium borate glasses  

Microsoft Academic Search

It is shown the possibility to determine the coordination of paramagnetic ions in disordered solid structures, e.g., in barium\\u000a borate glasses. For this purpose the electron paramagnetic resonance (EPR) method was used to study ?-and ?-BaB2O4 crystals and glasses of 45·BaO × 55·B2O3 and 40·BaO × 60·B2O3 (mol%) composition activated by Ag+ and Pb2+ ions. After the samples were exposed to X-rays at 77 K,

V. P. Solntsev; R. I. Mashkovtsev; A. V. Davydov; E. G. Tsvetkov

2008-01-01

112

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

SciTech Connect

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.

Khasa, S., E-mail: skhasa@rediff.com; Dahiya, M. S., E-mail: skhasa@rediff.com [Physics Department, Deenbandhu Chhotu Ram University of Science and Technology, Murthal-131039 (India); Agarwal, A. [Physics Department, Guru Jambheshwara University of Science and Technology, Hisar-125001 (India)

2014-04-24

113

Non-linear optical monitoring of glass transitions in doped lead-containing glasses  

NASA Astrophysics Data System (ADS)

Germanate glasses are interesting materials for photonics applications. Particularly PbO containing glasses are interesting because they combine high photomechanical stability and chemical durability with temperature stability and excellent transmission in the infrared spectral region (up to 4,5 ?m). Besides the low phonon energy (around 700 cm-1) compared to borates (around 1400cm -1) and phosphates (around 1200 cm-1) the glasses indicate low nonradiative relaxation rates and makes up conversion easily observable. The results of measurements of a dependence of SHG in these glasses with different Er, Eu, Ag impurities are reported together with thermal measurements of these glasses. We compared the DSC traces with temperature dependences of second order susceptibilities enhancement. Temperature dependence of the second-order optical susceptibilities detected by the SHG correlates well with the differential scanning calorimetric (DSC) measurements. It is demonstrated that although both methods give an evidence of the phase transitions the non-linear optical one is much more sensitive and temperature resolved. Possible physical origins of the observed phenomenon are discussed.

Piasecki, M.

2009-07-01

114

Preparation of hollow hydroxyapatite microspheres by the conversion of borate glass at near room temperature  

SciTech Connect

Hollow hydroxyapatite microspheres, consisting of a hollow core and a porous shell, were prepared by converting Li{sub 2}O-CaO-B{sub 2}O{sub 3} glass microspheres in dilute phosphate solution at 37 {sup o}C. The results confirmed that Li{sub 2}O-CaO-B{sub 2}O{sub 3} glass was transformed to hydroxyapatite without changing the external shape and dimension of the original glass object. Scanning electron microscopy images showed the shell wall of the microsphere was built from hydroxyapatite particles, and these particles spontaneously align with one another to form a porous sphere with an interior cavity. Increase in phosphate concentration resulted in an increase in the reaction rate, which in turn had an effect on shell wall structure of the hollow hydroxyapatite microsphere. For the Li{sub 2}O-CaO-B{sub 2}O{sub 3} glass microspheres reacted in low-concentration K{sub 2}HPO{sub 4} solution, lower reaction rate and a multilayered microstructure were observed. On the other hand, the glass microspheres reacted in higher phosphate solution converted more rapidly and produced a single hydroxyapatite layer. Furthermore, the mechanism of forming hydroxyapatite hollow microsphere was described.

Yao, Aihua, E-mail: aihyao@126.com [Institute of Bioengineering and Information Technology Materials, School of Materials Science and Engineering, Tongji University, Shanghai 200092 (China)] [Institute of Bioengineering and Information Technology Materials, School of Materials Science and Engineering, Tongji University, Shanghai 200092 (China); Ai, Fanrong; Liu, Xin; Wang, Deping; Huang, Wenhai; Xu, Wei [Institute of Bioengineering and Information Technology Materials, School of Materials Science and Engineering, Tongji University, Shanghai 200092 (China)] [Institute of Bioengineering and Information Technology Materials, School of Materials Science and Engineering, Tongji University, Shanghai 200092 (China)

2010-01-15

115

Helium diffusion in curium-doped borosilicate waste glass  

NASA Astrophysics Data System (ADS)

The isothermal release of helium from 244Cm-doped borosilicate glass has been studied as a function of time at different annealing temperatures. Helium measurements were performed using a micro gas chromatograph coupled to a furnace installed in a hot cell at ATALANTE nuclear research facility. Plane-parallel glass samples were prepared from glass discs that had been stored for 5.1 years at room temperature, accumulating around 10 19 alpha decays per gram of glass, a level that will be reached in current nuclear glass packages several thousand years after disposal. The experimental helium release data were simulated using a 3D numerical model to determine the helium diffusion coefficients. The extracted diffusion coefficients follow the Arrhenius law with an activation energy of 0.61 ± 0.03 eV and a pre-exponential factor of (5.7 ± 1.6) × 10 -3 cm 2 s -1. The results were compared with literature data on damaged and undamaged glasses to assess the effect of glass damage on helium release. The helium release results are consistent with a thermal diffusion mechanism involving only one population of helium atoms. The helium diffusion coefficients were unaffected by the glass alpha damage.

Fares, T.; Peuget, S.; Bouty, O.; Deschanels, X.; Magnin, M.; Jégou, C.

2011-09-01

116

Spectroscopic Properties of Er{sup 3+} Doped Phosphate Glass  

SciTech Connect

A series of erbium doped phosphate glass has been successfully prepared using melt quenching technique. The glass density is decreased as the glass host content increases. The infrared absorption spectroscopy has been carried out to this series of glass. The samples exhibit five absorption bands in the range of 400-1400 cm{sup -1}. The peaks assigned to P=O{sub (s)}, PO{sub 2(s)}, P-O{sup -}, P-O-P{sub (s)} and PO{sub 4}{sup 3-}. Meanwhile, the luminescence spectroscopy shows the emission spectra of {sup 2}H{sub 9/2}, {sup 4}F{sub 3/2}, {sup 4}F{sub 7/2} and {sup 4}I{sub 9/2} at their transition level. The transition of {sup 4}F{sub 7/2} gives strong and weak emission peak.

Rohani, M. S.; Rasid, A. A.; Sahar, M. R.; Kassim, A. [Advanced Optical Materials Research Group, Physics Dept., Faculty of Science, Universiti Teknologi Malaysia, 81310 UTM Skudai, Johor (Malaysia)

2010-03-11

117

Bismuth-doped Mg - Al silicate glasses and fibres  

SciTech Connect

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)

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

118

Photostimulated luminescence in Eu-doped fluorochlorozirconate glass ceramics  

NASA Astrophysics Data System (ADS)

We report the synthesis of Eu2+- and chlorine-doped fluorozirconate glass-ceramics that show an intense photostimulated luminescence (PSL) after x-ray irradiation at room temperature. The PSL efficiency is up to 80% of that found in the well-known crystalline x-ray storage phosphor BaFBr:Eu2+, and it is the largest thus far reported for a glass-ceramic. We attribute the PSL to crystallites of orthorhombic BaCl2 that are formed after annealing above the glass temperature. Hexagonal BaCl2 crystallites are also observed after short annealing times, but they do not provide a measurable PSL signal. The photoluminescence peak from glass-ceramics containing orthorhombic BaCl2 crystallites occurs at 402 nm, and the stimulation band is centered at about 560 nm.

Schweizer, Stefan; Hobbs, Linn W.; Secu, Mihail; Spaeth, Johann-Martin; Edgar, Andrew; Williams, Grant V. M.

2003-07-01

119

Diode pumped white light emission from dysprosium and samarium doped glasses  

NASA Astrophysics Data System (ADS)

Glasses embedded with Dysprosium and Samarium were made by the melt quenching technique. Dy3+ -doped glasses exhibited bright white luminescence under 10 mW of 405 nm diode laser excitation. Color rending index of the glass was improved by adding Sm3+ as a co-dopant to the glass. Spectroscopic results of the glasses are discussed.

Reddy, B. Rami; Edwards, Vernessa M.; Surabhi, Raja

2014-03-01

120

Silver doped nanobioactive glass particles for bone implant applications  

SciTech Connect

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.

Prabhu, M.; Kavitha, K.; Karunakaran, G.; Manivasakan, P.; Rajendran, V. [Centre for Nanoscience and Technology, K. S. Rangasamy College of Technology, Tiruchengode - 637215, Namakkal (DT), Tamil Nadu (India)

2013-02-05

121

Spectral luminescence characteristics of forsterite nano glass ceramics doped with chromium ions  

NASA Astrophysics Data System (ADS)

A technology for production of nano-glass-ceramic materials based on aluminosilicate glass doped with chromium oxide is proposed. A comparative study of the spectral luminescence properties of forsterite glass ceramics and single crystal doped with chromium ions is performed. It is shown that chromium ions are partially incorporated into the glass-ceramics crystalline phase. The quantum luminescence yields of Cr4+ ions in forsterite nano glass ceramics and single crystal are found to be close.

Aseev, V. A.; Zhukov, S. N.; Kuleshov, N. V.; Kuril'chik, S. V.; Mudryi, A. V.; Nikonorov, N. V.; Rokhmin, A. S.; Yasyukevich, A. S.

2015-01-01

122

Enhanced luminescence in Er3+ -doped chalcogenide glass-ceramics based on selenium  

E-print Network

Enhanced luminescence in Er3+ -doped chalcogenide glass-ceramics based on selenium Mathieu Huberta doped glass-ceramics transparent in the infrared region up to 16 µm have been prepared and studied in a selenium- based glass-ceramic having a composition of 80GeSe2-20Ga2Se3+1000 ppm Er. The optical

Boyer, Edmond

123

Luminescence properties of Cr-doped silica sol gel glasses  

NASA Astrophysics Data System (ADS)

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.

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

1997-11-01

124

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

SciTech Connect

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.

Babu, P.; Jang, Kyoung Hyuk; Kim, Eun Sik; Shi, Liang; Seo, Hyo Jin [Department of Physics, Pukyong National University, Busan 608-737 (Korea, Republic of); Rivera-Lopez, F.; Rodriguez-Mendoza, U. R.; Lavin, V. [Departamento de Fisica Fundamental y Experimental, Electronica y Sistemas, Universidad de La Laguna, E-38200 San Cristobal de La Laguna, Santa Cruz de Tenerife (Spain); Vijaya, R.; Jayasankar, C. K.; Rama Moorthy, L. [Department of Physics, Sri Venkateswara University, Tirupati 517 502 (India)

2009-01-01

125

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

SciTech Connect

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.

Borodi, G. [National Institute for Research and Development of Isotopic and Molecular Technologies, 65-103 Donath, 400293 Cluj-Napoca (Romania)] [National Institute for Research and Development of Isotopic and Molecular Technologies, 65-103 Donath, 400293 Cluj-Napoca (Romania); Pascuta, P.; Dan, V.; Pop, V. [Technical University, 28 Memorandumului, 400114 Cluj-Napoca (Romania)] [Technical University, 28 Memorandumului, 400114 Cluj-Napoca (Romania); Stefan, R. [Agricultural Science and Veterinary Medicine University, 3-5 Calea Manastur, 400372 Cluj-Napoca (Romania)] [Agricultural Science and Veterinary Medicine University, 3-5 Calea Manastur, 400372 Cluj-Napoca (Romania); Radulescu, D. [University of Medicine and Pharmacy Iuliu Hatieganu, 8 Victor Babes, 400012 Cluj-Napoca (Romania)] [University of Medicine and Pharmacy Iuliu Hatieganu, 8 Victor Babes, 400012 Cluj-Napoca (Romania)

2013-11-13

126

Er 3+-doped tellurite glass waveguides produced by fiber on glass (FOG) method  

NASA Astrophysics Data System (ADS)

In this work we used a Thermal Mechanic Analysis equipment to produce the channel FOG waveguides by pressing an Er 3+ doped tellurite glass optical fiber against one Er 3+ ion doped tellurite glass substrate kept under T c +/- 30 °C (T c = soft point). The luminescence and waveguide refractive index were measured. Scanning electron microscopy was used to observe the obtained structure. The objective is to produce a new concept in components of integrated optical circuits. Then this work report the production of Er 3+-doped tellurite glass channel waveguides using the novel concept of Benson et al [1] of fiber on glass (FOG). To succeed with this technique it is important to correlate the main thermo-physical characteristics of the substrate and the fiber, which are the transition temperature T g, the temperature of the onset of crystallization T x, the maximum crystallization temperature T c and the thermal expansion coefficient. The T g, T x and T c values were determined by Differential Thermal Analysis (DTA), while the thermal expansion coefficient was determined by Thermal Mechanical Analysis (TMA). For the FOG purpose the thermal stability range, T x - T g, is an important temperature region which defines if the glass will have enough viscosity to shape in the FOG concept.

Rivera, V. A. G.; Rodriguez, E.; Chillcce, E. F.; Mazali, I. O.; Cesar, C. L.; Barbosa, L. C.

2006-02-01

127

Density, Electrical and Optical Properties of Yttrium-Containing Tellurium Bismuth Borate Glasses  

NASA Astrophysics Data System (ADS)

60B2O3-30Bi2O3-(10 - x) TeO2- xY2O3 mol.% ( x = 0, 0.1, 1, 2 and 5) glasses have been prepared by the conventional glass-melting technique. The influence of Y2O3 on the density, optical and electrical properties of the glass was investigated. The density decreased whereas the molar volume increased with increasing Y2O3. Optical transmission in the ultraviolet (UV) spectral region indicated that the values of direct and indirect optical band gap energies increased, which was attributed to structural changes induced by the addition of Y2O3. Urbach energy values decreased with increasing the Y2O3, which was attributed to a decrease in the broadening due to static disorder-related parts. Fourier transform infrared (FTIR) spectra revealed that the addition of Y2O3 transforms BO4 to BO3 and BiO3 to BiO6 groups. The decrease in the dc and ac electrical conductivities was attributed to the formation of [BiO6] units which leads to a decrease in acceptor levels of Bi5+ sites. The electric modulus formalism indicated that the conductivity relaxation at different frequencies was a temperature-independent dynamic process. The full width at half-maximum (FWHM) of the normalized modulus decreases with increasing Y2O3 content, suggesting that the decrease of the Y ion-ion distance increases the interaction between the Y ions.

Shaaban, M. H.; Ali, A. A.

2014-11-01

128

Copper Doped Waveguides in Glass Substrates  

NASA Astrophysics Data System (ADS)

We have studied the fabrication and properties of the copper ion exchanged waveguides that were fabricated in special Na 2 O-rich soda-lime silicate glasses and in commercial BK7 optical glass substrates. The ion exchange was performed in melts containing either Cu I or Cu II at temperatures from 350°C to 500°C for times ranging from 5 min to 21 h. Optical properties of the fabricated waveguides were studied using mode spectroscopy and photoluminescence spectroscopy, and composition of the waveguides was determined by using Scanning Electron Microscope (SEM), Rutherford Backscattering Spectrometry (RBS), Electron Paramagnetic Resonance (EPR), and Electron Spectroscopy for Chemical Analysis (ESCA). After the ion exchange the refractive index increased, according to fabrication conditions, up to ?n = +0.0693, and the guides supported up to 16 TE and TM modes. The Cu I ?Cu II redox reaction during the fabrication depended strongly on the composition as well as the temperature of the reaction melts. In the Cu 2 Cl 2 :ZnCl 2 melts, the oxidation of Cu I to Cu II was strongly impeded, so that Cu I prevailed in the waveguiding region. These samples exhibited the most intensive blue-green luminescence in spite of those fabricated by using the Cu II -based reaction melts, where practically no blue-green luminescence was observed. ESCA measurement revealed an easy charge transfer between both oxidation states of copper in the very surface regions of the samples.

Špirková, Jarmila; Nebolová, Pavlína; Jirka, Ivan; Mach, Karel; Pe?ina, Vratislav; Macková, Anna; Kuncová, Gabriela

129

Nitrogen doped germania glasses with enhanced optical and mechanical properties  

SciTech Connect

A new type of ultraviolet photosensitive germanium doped glass has been developed for use in the fabrication of optical waveguide structures. By adding ammonia to the source gases during a plasma enhanced chemical vapor deposition of these glasses, ultraviolet induced refractive index changes of up to 3.4 {times} 10{sup {minus}3} have been obtained. Although this is, to the best of the authors` knowledge, a record for germanium doped silica films not photosensitized by hydrogen loading, results show that even larger changes in the refractive index can be induced. Stable glasses with refractive indexes from 1.460 to 1.518 have been formed throughout the composition range from 0 to 30% germanium by including ammonia in the deposition process. Not only is it possible to increase the photosensitivity, but it is also possible to control stress in these films. Depending on the deposition and annealing conditions, these glass films can be made to exhibit a range of stress from compressive to low tensile when deposited on silicon wafers.

Storgaard-Larsen, T. [Brueel and Kjoer A/S, Noerum (Denmark); Poulsen, C.V. [Univ. of Southampton (United Kingdom). Optoelectronics Research Centre; Leistiko, O. [Technical Univ. of Denmark, Lyngby (Denmark). Microelectronics Centre

1997-06-01

130

Characterization of borate glasses by W-band pulse electron-nuclear double resonance spectroscopy  

NASA Astrophysics Data System (ADS)

(100-x)mol% B2O3 x mol % Me2O (Me=Li,Na,K) glasses, exposed to ?-Co60 irradiation to produce paramagnetic states, were characterized by W-band (95GHz ) pulse electron-nuclear double resonance (ENDOR) spectroscopy in order to characterize local structures occurring in the range of compositions between x =16 and x =25 at which the "boron oxide" anomaly occurs. The high resolution of nuclear frequencies allowed resolving the Li7 and B11 ENDOR lines. In the samples with x =16 and x =20 glasses, B11 hyperfine couplings of 16, 24, and 36MHz were observed and attributed to the tetraborate, triborate, and boron oxygen hole center (BOHC) structures, respectively. The x =25 samples showed hyperfine couplings of 15MHz for the tetraborate and 36MHz for BOHC. Density functional theory (DFT) calculations predicted for these structures negative hyperfine couplings, which were confirmed by W-band ENDOR. This suggests that a spin polarization mechanism accounts for the negative hyperfine structure splitting.

Kordas, George; Goldfarb, Daniella

2008-10-01

131

Characterization of borate glasses by W-band pulse electron-nuclear double resonance spectroscopy  

SciTech Connect

(100-x) mol % B{sub 2}O{sub 3} x mol %Me{sub 2}O (Me=Li,Na,K) glasses, exposed to {gamma}-{sup 60}Co irradiation to produce paramagnetic states, were characterized by W-band (95 GHz) pulse electron-nuclear double resonance (ENDOR) spectroscopy in order to characterize local structures occurring in the range of compositions between x=16 and x=25 at which the 'boron oxide' anomaly occurs. The high resolution of nuclear frequencies allowed resolving the {sup 7}Li and {sup 11}B ENDOR lines. In the samples with x=16 and x=20 glasses, {sup 11}B hyperfine couplings of 16, 24, and 36 MHz were observed and attributed to the tetraborate, triborate, and boron oxygen hole center (BOHC) structures, respectively. The x=25 samples showed hyperfine couplings of 15 MHz for the tetraborate and 36 MHz for BOHC. Density functional theory (DFT) calculations predicted for these structures negative hyperfine couplings, which were confirmed by W-band ENDOR. This suggests that a spin polarization mechanism accounts for the negative hyperfine structure splitting.

Kordas, George [Sol Gel Laboratory for Glass and Ceramics, Institute of Materials Science, NCSR 'Demokritos', 15310 Aghia Paraskevi Attikis (Greece); Goldfarb, Daniella [Department of Chemical Engineering, Weizmann Institute of Science, 76100 Rehovot (Israel)

2008-10-21

132

Determination of major, minor and trace elements in rock samples by laser ablation inductively coupled plasma mass spectrometry: Progress in the utilization of borate glasses as targets  

NASA Astrophysics Data System (ADS)

The present work is a continuation of a research study performed at our laboratory aiming at the multielement analysis of rock samples (basalts and shale) by inductively coupled plasma mass spectrometry in combination with laser ablation using borate glasses as analytical targets. Argon, nitrogen-argon mixtures and helium were evaluated as cell gases, the latter confirming its better performance. Different operational parameters of the laser, such as gas flow, energy, focus, scanning speed and sampling frequency were optimized. External calibration was made with standards prepared by fusion of geological reference materials (basalts 688 and BCR-2, obsidian SRM 278, and shale SGR-1) of different mass fractions in the meta-tetra borate matrix. Coefficients of determination ( R2) were > 0.99 for 30 elements from o total of 40 determined. Method validation was then performed using additional certified reference materials (BHVO-2, BIR-1, SCo-1) produced as borate targets in a similar way. Accuracies were better than 10% for most of the elements studied and analytical precisions, calculated from the residual standard deviations of calibration curves were, typically, between 6% and 10%. Additionally, the semiquantitative TotalQuant® technique was applied, which gave, within the expected uncertainty for this calibration technique, concordant results when compared to the quantitative external calibration procedure. Both methods were then used for the analysis of marine shale samples, which are of great geological interest in petroleum prospecting.

Leite, Tácito Dantas F.; Escalfoni, Rainério, Jr.; da Fonseca, Teresa Cristina O.; Miekeley, Norbert

2011-05-01

133

AC Conductivity Studies in Lithium-Borate Glass Containing Gold Nanoparticles  

NASA Astrophysics Data System (ADS)

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.

Shivaprakash, Y.; Anavekar, R. V.

2011-07-01

134

Study of lithium borate glasses containing Bi{sub 2}O{sub 3}  

SciTech Connect

The effect of Bi{sub 2}O{sub 3} addition on the properties of 30Li{sub 2}O:(70?x)B{sub 2}O{sub 3}:xBi{sub 2}O{sub 3} (0?x?35 mol %) has been studied. Density and molar volume are increasing with Bi{sub 2}O{sub 3} content. The observed decrease in glass transition temperature and optical band gap has been explained on the basis of increase in non bridging oxygen which is supported by infrared spectroscopy. From the optical transmittance spectra it is observed that the cut off wavelength increases with Bi{sub 2}O{sub 3} content which is related to the structural changes.

Deshpande, A. V. [Department of Applied Physics, Visvesvaraya National Institute of Technology, Nagpur-440010 (India); Raut, V. D., E-mail: vijaya.raut@raisoni.net [Department of Applied Physics, G.H. Raisoni College of Engineering, Nagpur-440016 (India)

2014-04-24

135

Synthesis and spectroscopic studies of Fe3+-doped zinc borate powder  

NASA Astrophysics Data System (ADS)

Fe3+-doped Zn3(BO3)2 powder is synthesized using a co-precipitation method. Powder X-ray diffraction (PXRD), scanning electron microscopy (SEM), optical absorption, electron paramagnetic resonance (EPR), photoluminescence (PL), and Fourier transformation infrared (FTIR) spectroscopy were used to analyze the synthesized sample. The PXRD patterns confirm the monoclinic structure of the as-prepared sample. SEM images reflect the surface morphology of the sample. Energy dispersive X-ray spectroscopy (EDX) data confirms the presence of dopant ions in the host lattice. Crystal field (Dq) and inter-electronic repulsion (B and C) parameters were evaluated. The EPR spectrum shows two resonance signals, at g = 2.12 and 4.36. This indicates the existence of Fe3+ ions in tetragonally distorted octahedral site symmetry. The PL spectrum shows ultraviolet emission at room temperature. FT-IR spectroscopy confirms the fundamental vibrational bands of host molecules.

Venkata Reddy, Ch.; Shim, Jaesool; Byon, Chan; Sarma, G. V. S. S.; Narayana Murthy, P.; Ravikumar, R. V. S. S. N.

2015-02-01

136

Blocking effect of crystal–glass interface in lanthanum doped barium strontium titanate glass–ceramics  

SciTech Connect

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.

Wang, Xiangrong [Beijing Fine Ceramics Laboratory, State Key Laboratory of New Ceramics and Fine Processing, Institute of Nuclear and New Energy Technology, Tsinghua University, Beijing 100084 (China); Zhang, Yong, E-mail: yzhang@tsinghua.edu.cn [Beijing Fine Ceramics Laboratory, State Key Laboratory of New Ceramics and Fine Processing, Institute of Nuclear and New Energy Technology, Tsinghua University, Beijing 100084 (China); Baturin, Ivan [Ferroelectric Laboratory, Institute of Natural Science, Ural Federal University, Ekaterinburg 620000 (Russian Federation); Liang, Tongxiang [Beijing Fine Ceramics Laboratory, State Key Laboratory of New Ceramics and Fine Processing, Institute of Nuclear and New Energy Technology, Tsinghua University, Beijing 100084 (China)

2013-10-15

137

Mode-locking of neodymium lasers by glasses doped with PbS nanocrystals  

Microsoft Academic Search

Nonlinear optical absorption properties of silicate glasses doped by the PbS nanocrystals were investigated by means of the picosecond pump-probe absorption spectroscopy and absorption bleaching technique. The glass samples were used as saturable absorbers for passive mode-locking of Nd?:?YAG and Nd?:?glass lasers. Application of the PbS doped glass together with the active mode-locking and laser cavity quality control enabled the

A. Dementjev; V. Gulbinas; L. Valkunas; I. Motchalov; H. Raaben; A. Michailovas

2003-01-01

138

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

PubMed

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 ?m) 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. PMID:23233025

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

2013-03-01

139

Population dynamics in Er3+-doped fluoride glasses  

NASA Astrophysics Data System (ADS)

A detailed study of the energy-transfer processes in Er3+: flouride glasses with doping concentrations of 0.2-18 mol % is presented. Fluorescence wave forms for 11 erbium transitions were measured under 802-nm, 1.5-?m, 975-nm, 520-nm, and 403-nm excitation from a high-energy short-pulse source. The analysis of these data provided a physical understanding of the processes responsible for the temporal behavior of the populations of a large number of energy levels. A comprehensive nine-level rate-equation model of the Er3+ population dynamics in these fluoride glasses is developed. The model performs well in predicting the observed fluorescence behavior of the main fluorescing lines under all pumping conditions. The modeling process allowed 14 ion-ion energy-transfer processes that are important for the population dynamics in these fluoride glasses to be identified and their rate constants obtained. Noticeably, the inclusion of seven three-ion processes was found necessary in order to obtain good fits to the experimental fluorescence wave forms. It was also found that some three-ion processes have a significant effect on the population dynamics of the levels even in lower doping concentrations.

Bogdanov, V. K.; Booth, D. J.; Gibbs, W. E.; Javorniczky, J. S.; Newman, P. J.; Macfarlane, D. R.

2001-05-01

140

Effect of ytterbium co-doping on erbium clustering in silica-doped glass  

NASA Astrophysics Data System (ADS)

The effect of ytterbium co-doping on erbium ion clustering in silica-based glass was studied. It was experimentally shown that the pump-to-signal conversion efficiency could be significantly increased if the number of Yb3+ ions in the fiber core was 20 times higher than the number of Er3+ ions. Estimations of the number of Er3+ ions in clusters confirmed a decrease in their clustering at high Yb concentrations.

Kiritchenko, N. V.; Kotov, L. V.; Melkumov, M. A.; Likhachev, M. E.; Bubnov, M. M.; Yashkov, M. V.; Laptev, A. Yu; Guryanov, A. N.

2015-02-01

141

Spectroscopy of vanadium (III) doped gallium lanthanum sulphide chalcogenide glass  

E-print Network

Vanadium doped gallium lanthanum sulphide glass (V:GLS) displays three absorption bands at 580, 730 and 1155 nm identified by photoluminescence excitation measurements. Broad photoluminescence, with a full width half maximum (FWHM) of 500 nm, is observed peaking at 1500 nm when exciting at 514, 808 and 1064 nm. The fluorescence lifetime and quantum efficiency at 300 K were measured to be 33.4 us and 4 % respectively. From the available spectroscopic data we propose the vanadium ions valence to be 3+ and be in tetrahedral coordination The results indicate potential for development of a laser or optical amplifier based on V:GLS.

Hughes, M; Rutt, H; Hewak, D

2014-01-01

142

Synthesis and spectroscopy of tetraborate glasses doped with copper  

Microsoft Academic Search

Lithium and potassium–lithium tetraborate glasses doped with Cu (Li2B4O7:Cu and KLiB4O7:Cu) of high optical quality were obtained from polycrystalline compounds by fast cooling of the corresponding melt. Cu impurity was added to the Li2B4O7 and KLiB4O7 compounds in the form of a CuO oxide in the amounts of 0.4 and 1.6mol.%. On the basis of EPR and optical spectroscopy (absorption,

B. Padlyak; W. Ryba-Romanowski; R. Lisiecki; O. Smyrnov; A. Drzewiecki; Ya. Burak; V. Adamiv; I. Teslyuk

2010-01-01

143

Enhanced photoluminescence emission from anthracene-doped polyphenylsiloxane glass.  

PubMed

Anthracene-doped polyphenylsiloxane (PPS) glass containing silver nanoparticles (AgNPs) of appropriate size was synthesized in a form of solid thin films for modifying light emission characteristics. The photoluminescence (PL) emission from the anthracene molecules at ~2.95 eV was resonantly coupled to the localized surface plasmon (LSP) polariton modes that were induced by the excitation of ~30 nm sized AgNPs. The increase in absorption of incident photons within a highly scattering medium, energy transfer from the localized excitons to the LSP modes, and the electrostatic Coulomb effects of the excitons in the presence of metal NPs all resulted in a significant enhancement of PL emission. The PL enhancement is dependent on the concentration of the anthracene molecules. The integrated PL intensity enhancement at the optimum concentration of anthracene molecules in the PPS glass with AgNPs is found to exceed 50. PMID:24322223

Kimura, Megumi; Tarutani, Naoki; Takahashi, Masahide; Karna, Sanjay; Neogi, Arup; Shimada, Ryoko

2013-12-15

144

Active waveguide fabrication in erbium-doped oxyfluoride silicate glass using femtosecond pulses  

E-print Network

Active waveguide fabrication in erbium-doped oxyfluoride silicate glass using femtosecond pulses R September 2005 By directly writing waveguides inside bulk erbium-doped oxyfluoride silicate glass using and crystals.2 Recently, we have demonstrated that active waveguides may be fabricated inside erbium

145

Thermal Analysis of Sulfide Ge—Ga Glasses Doped by Praseodymium  

Microsoft Academic Search

The present study shows the dependence of the temperature of glass transition — T\\u000ag upon the presence and quantity of doping Pr atoms. Substantial effect of the form — chemical nature of compound from which the doping atoms are incorporated into the glass has been displayed as well. With the increase of the content of sulfidic form T\\u000ag

M. Drábik; T. Kozák; D. Ležal; M. Poulain; J. Kalužný

2002-01-01

146

Luminescent properties of Tb3+ and Gd3+ ions doped aluminosilicate oxyfluoride glasses.  

PubMed

Tb(3+) and Gd(3+) ions doped lithium-barium-aluminosilicate oxyfluoride glasses have been prepared. The transmission, emission and excitation spectra were measured. It has been found that those Tb(3+)-doped lithium-barium-aluminosilicate oxyfluoride glasses exhibit good UV-excited luminescence. The luminescence intensity of Tb(3+) ion increases for those (Tb(3+), Gd(3+))-codoped glasses. Energy transfer process from Gd(3+) ion to Tb(3+) ion is indicated. PMID:21831699

Zuo, Chenggang; Lu, Anxian; Zhu, Ligang; Zhou, Zhihua; Long, Woyun

2011-11-01

147

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

SciTech Connect

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.

Bocheux, A.; Robin, I. C.; Bonaimé, J.; Hyot, B.; Feuillet, G. [CEA, LETI, Département Optronique, F-38054 Grenoble (France); Kolobov, A. V.; Fons, P. [Nanodelectronics Research Institute, National Institute of Advanced Industrial Science and Technology, Tsukuba Central 4, Higashi 1-1-1, Tsukuba, Ibaraki 305-8562 (Japan); SPring-8, Japan Synchrotron Radiation Institute (JASRI), Kouto 1-1-1, Sayo-cho, Sayo-gun, Hyogo 679-5148 (Japan); Mitrofanov, K. V.; Tominaga, J. [Nanodelectronics Research Institute, National Institute of Advanced Industrial Science and Technology, Tsukuba Central 4, Higashi 1-1-1, Tsukuba, Ibaraki 305-8562 (Japan); Tamenori, Y. [SPring-8, Japan Synchrotron Radiation Institute (JASRI), Kouto 1-1-1, Sayo-cho, Sayo-gun, Hyogo 679-5148 (Japan)

2014-05-21

148

Broad-Spectrum Bactericidal Activity of Ag2O-Doped Bioactive Glass  

Microsoft Academic Search

Bioactive glass has found extensive application as an orthopedic and dental graft material and most recently also as a tissue engineering scaffold. Here we report an initial investigation of the in vitro antibacterial properties of AgBG, a novel bioactive glass composition doped with Ag2O. The bacteriostatic and bactericidal properties of this new material and of two other bioactive glass compositions,

Maria Bellantone; Huw D. Williams; Larry L. Hench

2002-01-01

149

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

PubMed

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. PMID:20544804

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

2010-10-01

150

Laser beam irradiation of silver doped silicate glasses  

NASA Astrophysics Data System (ADS)

Planar light waveguides prepared by Ag-Na ion exchange in molten salt bath are irradiated with Nd:YAG laser beams at different wavelengths in the IR and VIS regions, and for different energy density and repetition rate values. The samples are characterized by optical spectroscopy to determine the role of irradiation parameters in the Ag clustering process, including aggregation phenomena and possible cluster photofragmentation. The appearance of the characteristic plasmon resonance feature in the optical absorption spectra marks the formation of Ag clusters, as observed by electronic microscopy as well, and permits to follow the evolution of the whole clustering process upon increasing of the deposited energy density. Photoluminescence spectroscopy has given specific information concerning the presence of Ag multimeric aggregates, considered as embryonic structures for the growing nanoclusters. The systematic investigation presented in this work is expected to clarify some aspects of the interaction between the laser beam and the doped glass matrix, and to help establishing suitable methodologies for the controlled preparation of nanocomposite glasses.

Trave, E.; Gonella, F.; Calvelli, P.; Cattaruzza, E.; Canton, P.; Cristofori, D.; Quaranta, A.; Pellegrini, G.

2010-10-01

151

Antimicrobial effect of silver-doped phosphate-based glasses.  

PubMed

In this study a range of phosphate-based glasses (PBG) doped with silver have been investigated for their antimicrobial activities. In disk diffusion assays, these compositions demonstrated microbistatic effects against a range of organisms including Staphylococcus aureus, Escherichia coli, Bacillus cereus, Pseudomonas aeruginosa, methicillin-resistant Staphylococcus aureus, and Candida albicans. The data obtained from the above studies allowed for an additional range of PBG containing lower amounts of silver to be studied for their effects on the growth and viability of S. aureus, E. coli, and C. albicans. PBG containing 3 and 5 mol % Ag were bactericidal for S. aureus and E. coli and significantly decreased the growth rate of C. albicans. A decrease in the dissolution rates of the glasses was seen with increasing Ag content over the range of concentrations investigated. Overall, 3 mol % Ag incorporated into the PBG investigated was sufficient to mount a potent antibacterial effect against the test organisms, and these compositions also gave excellent long-term release of Ag ions into the medium. PMID:16826601

Ahmed, I; Ready, D; Wilson, M; Knowles, J C

2006-12-01

152

Laser properties of an improved average-power Nd-doped phosphate glass  

SciTech Connect

The Nd-doped phosphate laser glass described herein can withstand 2.3 times greater thermal loading without fracture, compared to APG-1 (commercially-available average-power glass from Schott Glass Technologies). The enhanced thermal loading capability is established on the basis of the intrinsic thermomechanical properties (expansion, conduction, fracture toughness, and Young`s modulus), and by direct thermally-induced fracture experiments using Ar-ion laser heating of the samples. This Nd-doped phosphate glass (referred to as APG-t) is found to be characterized by a 29% lower gain cross section and a 25% longer low-concentration emission lifetime.

Payne, S.A.; Marshall, C.D.; Bayramian, A.J. [and others

1995-03-15

153

Study on the laser-induced darkening in Nd-doped laser glasses  

Microsoft Academic Search

Laser induced darkening in the soda-lime silicate (15Na2O·15CaO·70SiO2) based glass and type N31 barium metaphosphate Ba(PO3)2 based glass were studied by exposing the glass samples in frequency-quadrupled Nd:YAG (266 nm, 5 ns) laser and Ti:Sapphire (800 nm, 120 fs) laser. Both types of the glasses were doped with Nd2O3 at doping levels less than 3 wt%. Hole center HC1 formed

Qinling Zhou; Lei Xu; Liying Liu; Wencheng Wang; Congshan Zhu; Fuxi Gan

2004-01-01

154

Erbium-doped transparent glass ceramic optical Characterization using mass spectroscopy and molecular dynamics modeling.  

E-print Network

Erbium-doped transparent glass ceramic optical fibres: Characterization using mass spectroscopy properties of the erbium ions embedded within the phospho-silicate DNP. These results permit to get more

Boyer, Edmond

155

Enhanced broadband near-infrared luminescence of Bi-doped oxyfluoride glasses.  

PubMed

Broadband near-infrared luminescence covering 900 to 1600 nm has been observed in Bi-doped oxyfluoride silicate glasses. The partial substitution of fluoride for oxide in Bi-doped silicate glasses leads to an increase of the intensity and lifetime of the near-infrared luminescence and blue-shift of the near-infrared emission peaks. Both Bi-doped silicate and oxyfluoride silicate glasses show visible luminescence with blue, green, orange and red emission bands when excited by ultra-violet light. Careful investigation on the luminescence properties indicates that the change of near-infrared luminescence is related to optical basicity, phonon energy of the glass matrix and crystal field around Bi active centers. These results offer a valuable way to control the luminescence properties of Bi-doped materials and may find some applications in fiber amplifier and fiber laser. PMID:23263148

Xu, Beibei; Tan, Dezhi; Zhou, Shifeng; Hong, Zhanglian; Sharafudeen, Kaniyarakkal N; Qiu, Jianrong

2012-12-17

156

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

NASA Astrophysics Data System (ADS)

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 (?E) 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.

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

2014-11-01

157

Nitrogen-ion-implanted planar optical waveguides in Er-doped tellurite glass: fabrication and characterization  

Microsoft Academic Search

Fabrication of channel waveguides in Er-doped tungsten-tellurite glasses was recently demonstrated. In order to get a deeper understanding of the process and to optimize the characteristics of the waveguides, we fabricated a set of planar waveguides, each of 7 mm × 7 mm lateral dimensions, in an Er-doped tellurite glass sample by implantation of 1.5 MeV nitrogen ions. Doses of

I. Bányász; S. Berneschi; I. Cacciari; M. Fried; T. Lohner; G. Nunzi-Conti; F. Pászti; S. Pelli; P. Petrik; G. C. Righini; A. Watterich; Z. Zolnai

2008-01-01

158

Erbium-doped ion-exchanged waveguide lasers in BK7 glass  

Microsoft Academic Search

Ion-exchange in glass is a simple, flexible technique to realize optical fiber-compatible planar waveguide devices. Recently, neodymium-doped waveguide lasers operating at 1060 and 1300 nm have been demonstrated in this technology. Lasers operating at 1540 nm are desirable for telecommunication applications and the authors report for the first time ion-exchanged waveguide lasers in erbium-doped glass emitting at this wavelength. Lasers

T. Feuchter; E. K. Mwarania; J. Wang; L. Reekie; J. S. Wilkinson

1992-01-01

159

Cation effects in NaPO/sub 3/ glasses doped with metal nitrides and oxides  

SciTech Connect

Oxynitride glasses were prepared by doping a NaPO/sub 3/ melt with either AlN, Mg/sub 3/N/sub 2/, or Ca/sub 3/N/sub 2/. NaPO/sub 3/ glasses doped with Al/sub 2/O/sub 3/, MgO, or CaO, so as to contain the same weight percent of each cation as in the oxynitride glasses were also prepared. The dissolution rate in water and the thermal expansion coefficient both decreased while the dilaometric softening point, glass transition temperature, and refractive index increased with increasing nitride or oxide dopant concentration. The properties of the corresponding oxide- or nitride-doped glasses were essentially equal, which indicated that the cation was primarily responsible for the change in each property.

Rajaram, M.; Day, D.E.

1986-05-01

160

Effect of 1 MeV electrons on ceria-doped solar cell cover glass  

NASA Technical Reports Server (NTRS)

The effect of 1 MeV electrons on the transmission properties of 1.5-percent ceria-doped solar cell cover glass was studied. Samples of doped and undoped cover glass and synthetic fused silica were irradiated with a total integrated flux of 10 to the 15th power e/sq cm. Wideband transmission and spectral transmission measurements were made before and after irradiation. The results indicate that 1.5-percent ceria-doped cover glass is much less sensitive to radiation induced discoloration than undoped cover glass. Consequently, the glass is comparable to synthetic fused silica when used as a radiation resistant solar cell cover for many space missions.

Haynes, G. A.

1973-01-01

161

Visible emission in Sm3+ and Tb3+ doped phosphate glass excited by UV radiation  

NASA Astrophysics Data System (ADS)

In the article analysis of UV absorption and visible fluorescence of Sm3+ and Tb3+ ions doped phosphate glass with molar composition: 65P2O5 + 8Al2O3 + 10BaO + 17(Na2O + MgO + ZnO) have been investigated. As a result of optical pumping fabricated glass with radiation from a deuterium lamp four luminescence bands were observed near to the wavelength of 600 nm for Sm3+ ions and 550 nm for Tb3+ ions. It was found that larger energy gap between laser and ground levels leads to the strongest emission in the visible range in terbium doped glasses than in glasses doped with samarium ions. Both fabricated glasses are characterized by the ability to selectively detect the radiation in the UV range.

Zmojda, Jacek; Dorosz, Dominik; Kochanowicz, Marcin; Miluski, Piotr; Czajkowski, Karol; Ragin, Tomasz

2013-10-01

162

Laser-induced radial birefringence and spin-to-orbital optical angular momentum conversion in silver-doped glasses  

E-print Network

online 8 July 2011) Samples of Agþ /Naþ ion-exchanged glass that have been subject to intense laser as resulting from thermally-induced stresses arising in the silver-doped glass during laser exposure, although. reported that initially isotropic silver- doped glasses become birefringent under strong laser illumination

Marrucci, Lorenzo

163

JOURNAL OF LIGHTWAVE TECHNOLOGY, VOL. 17, NO. 9, SEPTEMBER 1999 1593 Ytterbium-Doped Glass Waveguide Laser  

E-print Network

. Winick, Senior Member, IEEE, Member, OSA Abstract--A ytterbium-doped, glass, channel waveguide laser--Integrated optics, ion exchange, waveguide laser, ytterbium laser. I. INTRODUCTION Yb3 ions in glass and crystals [5]. In addition Yb3 has been widely used as a sensitizer for Er3 -doped glass amplifiers and lasers

Winick, Kim

164

Spectral properties of and energy transfer in Bi/Tm co-doped silicate glasses  

NASA Astrophysics Data System (ADS)

Bi, Tm singly doped and Bi/Tm co-doped glasses with molar compositions of 60SiO2-20Ga2O3-15Na2O-5Al2O3 were prepared by the conventional melt-quenching method. The enhanced emission of the Tm3+:3H4?3F4 transition at 1470 nm, and the quenched emission of the Tm3+:3F4?3H6 transition at 1860 nm were observed for Bi/Tm co-doped silicate glasses under 808 nm excitation. For 980 nm excitation, no Tm-related emission was observed for Tm singly doped glasses, while the emission of the Tm3+:3F4?3H6 transition at 1860 nm was observed for Bi/Tm co-doped glasses. These results indicated that the energy transfer occurred between active Bi ions and Tm3+ in Bi/Tm co-doped silicate glasses, in which the energy corresponding to the Bi-related emission level excited the Tm3+ from 3H6 to the 3H5 level under 980 nm excitation, and from 3F4 to the 3H4 level under 808 nm excitation. The energy-transfer processes were studied on the basis of the Inokuti-Hirayama model, and the energy transfer of the electric dipole-dipole interaction was confirmed to be dominant in Bi/Tm co-doped glasses. The Bi/Tm co-doped silicate glasses may be potential materials for producing broadband optical fiber amplifiers and tunable lasers.

Tang, Han; Xia, Haiping; Zhang, Yuepin; Hu, Haoyang; Jiang, Haochuan

2012-12-01

165

Bose Glass of Quasiparticles in Doped Quantum Magnet Gregory S. Boebinger, National High Magnetic Field Laboratory  

E-print Network

Bose Glass of Quasiparticles in Doped Quantum Magnet Gregory S. Boebinger, National High Magnetic magnet dichloro- tetrakis-thiourea-nickel (Br-DTN) forms magnetic order that is equivalent to a BEC-Bose Glass (BEC-BG) transition can be carefully controlled by magnetic field, allowing us to sensitively

Weston, Ken

166

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

NASA Astrophysics Data System (ADS)

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.

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

2011-05-01

167

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

NASA Astrophysics Data System (ADS)

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 Er2O3 doped TeO2-WO3-La2O3 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.

Sushama, D.

2014-10-01

168

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

NASA Technical Reports Server (NTRS)

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.

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

1997-01-01

169

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

PubMed

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. PMID:19079513

Lahoz, Fernando

2008-12-15

170

Neodymium-doped ion-exchanged waveguide lasers in BK7 glass  

Microsoft Academic Search

The availability of integrated optical sources in glass is expected greatly to enhance optical signal processing in glass substrates. A study of potassium ion-exchanged waveguide lasers in neodymium-doped BK-7 glass substrates is reported. Design parameters for low-threshold waveguide lasers with high slope efficiencies are described, and methods are given for the fabrication of substrates, waveguides and laser cavities. Properties of

Eustace K. Mwarania; Ji Wang; James S. Wilkinson

1993-01-01

171

Laser induced breakdown spectroscopy diagnosis of rare earth doped optical glasses  

SciTech Connect

In the present work, rare earth (Nd, Eu, Er, Ho) doped oxyfluoroborate glasses were studied using laser induced breakdown spectroscopy (LIBS) technique. It has been observed that rare earth elements other than the doped one also reveal their presence in the spectrum. In addition the spectral lines of elements constituting the glass matrix have also been observed. Different plasma parameters such as plasma temperature and electron density have been estimated. It is concluded that the LIBS is a potential technique to identify simultaneously the light elements (B, O, F) as well as the heavy elements (Fe, Ba, Ca, Eu, Nd, Ho, Er) present in optical glasses.

Dwivedi, Y.; Thakur, S. N.; Rai, S. B.

2010-05-01

172

Physical, thermal, infrared and optical properties of Nd3+ doped lithium-lead-germanate glasses  

NASA Astrophysics Data System (ADS)

The structure-property relationships of neodymium doped lithium-lead-germanate glasses were investigated. The density was found to increase with the increase of Nd2O3 concentration and its variation is explained in terms of its molecular mass, structural transformation and packing density. Addition of modifier oxide to lead-germanate glass suggests a decreased free space within the glass matrix, resulting in the formation of stiff network. The increase in glass transition temperature specifies strengthening of glass by forming bridging oxygens. The optical properties of glass were measured employing UV-visible spectroscopy. The refractive index values varied nonlinearly with Nd2O3 concentration and were speculated to depend on the electronic polarizability of oxide glasses. The frequencies of the infrared absorption bands were affected marginally and the absorption peaks revealed that the glass matrix consists of [GeO4/2], [GeO6/2] and [PbO4/2] structural units.

Veeranna Gowda, V. C.

2015-01-01

173

Synthesis, thermal and photoluminescent properties of ZnSe- based oxyfluoride glasses doped with samarium  

NASA Astrophysics Data System (ADS)

Rare earth (RE) doped glasses and glass ceramic materials have recently received considerable attention because of their potential or realized applications as X-ray intensifying screens, phosphors, detectors, waveguides, lasers etc. [1]. In this work, we present a new RE doped ZnO-ZnSe-SrF2-P2O5-B2O3-Sm2O3-SmF3 (ZSPB) glass system synthesized by melt quenching technique. The resulting glasses were visually fully transparent and stable with glass the transition temperatures around 530°C. The thermal properties of this glass system were characterized by Modulated Differential Scanning Calorimetry (MDSC) measurements before and after annealing at 650°C. We have characterized these glasses by Raman spectroscopy and photoluminescence (PL) measurements over the UV-VIS range using light emitting diodes (LED) and laser diodes (LD) excitation sources. We have also irradiated thermally treated and non-treated glass samples by X-rays and have studied the resulting PL. We discuss the results in terms of previously reported models for Sm-doped Zn-borophosphate oxide, oxyfluoride and oxyselenide glasses.

Kostova, I.; Okada, G.; Pashova, T.; Tonchev, D.; Kasap, S.

2014-12-01

174

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

NASA Astrophysics Data System (ADS)

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 (??), 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.

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

2014-11-01

175

Enhanced green upconversion luminescence in Yb-Tb co-doped sintered silica nanoporous glass  

NASA Astrophysics Data System (ADS)

We report on a new kind of green-emitting (543 nm) high-silica luminous glass, which is fabricated by sintering of Yb3+-Tb3+ co-doped nanoporous glass. The fluorescence spectra show that there is an energy transfer between Yb3+ and Tb3+. The energy transfer process can be enhanced by addition of Al3+ into the Yb3+-Tb3+ co-doped nanoporous glass, and the energy transfer rate can be enhanced more than three times than that of Yb3+-Tb3+ co-doped porous glass. The role of Al3+ has been discussed, and the fluorescence decay curve reveals that the Al3+ play an important role in the energy transfer process.

Chu, Yingbo; Yang, Yu; Liu, Zijun; Liao, Lei; Wang, Yibo; Li, Jiaming; Li, Haiqing; Peng, Jinggang; Dai, Nengli; Li, Jinyan; Yang, Luyun

2014-11-01

176

Optical properties and laser parameters of Nd 3+-doped flouride glasses  

NASA Astrophysics Data System (ADS)

Optical properties and laser parameters for 27 Nd 3+-doped flouride glasses are reported. Included are glasses based on zirconium flouride, hafnium flouride, and aluminum flouride and other glasses formed from mixtures of several heavy metal flourides. Measurements were made of the 4F 3/2? 4I 11/2 flourescence spectra and the concentration-dependent flourescence decays. Judd-Ofelt intensity parameters were derived from absorption spectra and used to calculate the 4F 3/2? 4I 11/2 stimulated emission cross section and the 4F 3/2 radiative lifetime. Cross sections showed only a small variation with glass composition, ranging from 2.2 to 3.4 pm 2; the radiative lifetimes ranged from 470 to 650 ?s. Results for these flouride glasses are compared with values for BeF 2-based glasses and for oxide and oxyflouride laser glasses.

Tesar, A.; Campbell, J.; Weber, M.; Weinzapfel, C.; Lin, Y.; Meissner, H.; Toratani, H.

1992-09-01

177

White light emission and energy transfer in Dy3+/Eu3+ co-doped aluminoborate glass  

NASA Astrophysics Data System (ADS)

The Dy3+ single doped calcium aluminoborate glass (CaO-Al2O3-B2O3-Dy2O3) was synthesized by melt quenching method and the photoluminescence properties of Dy3+ were studied. Under UV-light excitation the CaO-Al2O3-B2O3-Dy2O3 glass shows a yellowish white light emission and the optimum content of Dy3+ in glass is found at 0.022 mol. For getting pure white light emission, the Dy3+/Eu3+ co-doped glasses with the compositions of Ca0.978-yAlB:Dy3+0.022, Euy3+ (y = 0-0.0938 mol) have been synthesized and the chromatic coordinates were calculated from their emission spectra. The results showed that the white light has been achieved by exciting Dy3+/Eu3+ co-doped glass with ultraviolet or blue light. The energy transfer phenomenon between Dy3+ and Eu3+ ions was validated in Dy3+/Eu3+ co-doped glasses and the decay rates for 4F9/2 level of Dy3+ ions have been measured. The energy transfer probabilities (Pda) are linear with acceptor (Eu3+) contents in the range of 0-0.0563 mol, confirming the fact that the dipole-dipole interaction is responsible for the energy transfer (ET) process of Dy3+ ? Eu3+.

Cai, Jia-li; Li, Ruo-ying; Zhao, Chong-jian; Tie, Shao-long; Wan, Xia; Shen, Jun-ying

2012-05-01

178

Photoluminescence properties of singly doped Tm3+ and co-doped Tm3+/Tb3+ ions in tellurite glasses  

NASA Astrophysics Data System (ADS)

Photoluminescence properties of singly doped Tm3+ and co-doped Tm3+/Tb3+ ions in TZKC glasses with chemical composition of (61.5-x) TeO2 + 25 ZnO + 8 K2O + 5CaO + 0.5Tm2O3 + xTb4O7 (TZKCTm05Tbx; x (in mol%) = 0, 0.5, 1.0, 1.5) have been studied. The experimental oscillator strengths of absorption bands in TZKCTm05 glass were used to determine the host dependent Judd-Ofelt ?2, ?4, ?6 intensity parameters. The effective emission cross-section of 1.8 ?m emission band as a function of wavelength has been deduced by the McCumber's theory. Based on the absorption (?a) and emission cross-sections (?e), the gain co-efficients (G) of 1.8 ?m emission band for various population inversions between the emitting (3F4) and terminating (3H6) levels were evaluated. From the photoluminescence spectra of singly doped Tm3+ and co-doped Tm3+/Tb3+ ions in TZKC glasses, the chromaticity color coordinates (x, y) were estimated.

Sasikala, T.; Rama Moorthy, L.

2014-11-01

179

A novel ionizing radiation sensor utilizing radiophotoluminescence in silver-doped phosphate glass  

NASA Astrophysics Data System (ADS)

Silver (Ag+) doped phosphate glass exhibits an intense photoluminescence (PL) when the non-irradiated Ag+-doped phosphate glass is excited with about 230 nm ultra-violet light. In x-ray irradiated glass, intense radiophotoluminescense (RPL) is observed when the irradiated glass is excited with about 340 nm ultra-violet light. It is found that the RPL spectrum includes two emission bands such as blue emission band peaked at about 460 nm (lifetime: about 6.6 ns) and yellow RPL emission band peaked at about 560 nm (lifetime : about 2.2?s). The PL intensity is decreased with increasing x-ray irradiation dose, while the RPL intensity is increased with x-ray absorbed dose. For the annealing of x-ray irradiated glass at 523 K, the RPL intensity is decreased with annealing, while the PL intensity is increased with annealing. The RPL is vanished and the PL is recovered at original intensity by annealing at 523 K for 40 min. This means that there is a complementary relationship between the PL and RPL on irradiation and heat-treatment processes. The RPL intensity is increased with increasing the x-ray absorbed dose in the range from 0.01 mGy to about 20 Gy, showing that the Ag+-doped phosphate glass can be useful for individual radiation monitoring and environmental radiation monitoring. On the basis of such potentiality of glass as the dosimeter, the application of Ag+-doped phosphate glass on environmental radiation monitoring is discussed and the RPL response of the glass for ?- particle and heavy-particle (He, C, Fe particle) irradiation is demonstrated.

Nanto, H.; Miyamoto, Y.; Ohno, T.; Ikeguchi, T.; Hirasawa, K.; Takei, Y.; Kurobori, T.; Yamamoto, T.; Iida, T.

2014-03-01

180

Ytterbium-doped silica photonic crystal fiber laser fabricated by the nanoporous glass sintering technique  

NASA Astrophysics Data System (ADS)

Based on the sintering of ytterbium-doped nanoporous glass, a nonchemical vapor deposition process aimed at fabricating a large-mode area of photonic crystal fibers has been proposed for the preparation of active silica glass. With the relatively low doping concentration and boron in the silica glass as benefits, a close refractive index between the core and the cladding was obtained. The refractive index variation indicated good homogeneity of the doped fiber core. Up to 34.8?W laser output was demonstrated with the PCF laser and the slope efficiency was 71.3%. The output laser beam quality had slightly multimode behavior, with a mean M2 of 2.42.

Liu, Shuang; Wang, Meng; Zhou, Qinling; Feng, Suya; Yu, Chunlei; Wang, Longfei; Hu, Lili; Chen, Danping

2014-06-01

181

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

SciTech Connect

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.

Passlick, C. [Centre for Innovation Competence SiLi-nano registered , Martin Luther University of Halle-Wittenberg, Karl-Freiherr-von-Fritsch-Str. 3, 06120 Halle (Saale) (Germany); Mueller, O.; Luetzenkirchen-Hecht, D.; Frahm, R. [Bergische Universitaet Wuppertal, Gaussstrasse 20, 42097 Wuppertal (Germany); Johnson, J. A. [Department of Biomedical Engineering, University of Tennessee Space Institute, Tullahoma, Tennessee 37388 (United States); Schweizer, S. [Centre for Innovation Competence SiLi-nano registered , Martin Luther University of Halle-Wittenberg, Karl-Freiherr-von-Fritsch-Str. 3, 06120 Halle (Saale) (Germany); Fraunhofer Center for Silicon Photovoltaics CSP, Walter-Huelse-Str. 1, 06120 Halle (Saale) (Germany)

2011-12-01

182

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

SciTech Connect

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.

PaBlick, C.; Müller, O.; Lützenkirchen-Hecht, D.; Frahm, R.; Johnson, J.A.; Schweizer, S. (U. Halle); (Bergische); (Tennessee-C)

2012-10-10

183

Site of transition metal ions in ion-exchanged metal-doped glasses  

Microsoft Academic Search

Metal-for-alkali ion-exchange is largely used to dope surface layer of glass with metal ions so inducing a modification of the optical properties of the doped layer, useful to fabricate low-loss optical waveguides. X-ray absorption spectroscopy is a particularly important technique used to investigate the site of the metal ions introduced into the matrix, in specific cases also singling out the

C. Maurizio; F. D’Acapito; C. Sada; E. Cattaruzza; F. Gonella; G. Battaglin

2008-01-01

184

Spectroscopic investigation of the photochemistry of uranyl-doped sol-gel glasses immersed in ethanol  

SciTech Connect

Uranyl ion (UO{sub 2}{sup 2+}) has been doped in silica glasses through a sol-gel process. The photochemistry of UO{sub 2}{sup 2+}-doped glasses immersed in ethanol solution has been investigated. Our experimental results indicate that UO{sub 2}{sup 2+} in this system can be photochemically converted to U(IV) species, and evidence is provided for the possible formation of U(IV) species via a subsequent chemical reduction of the intermediate UO{sub 2}{sup +} instead of the conventional bimolecular disproportionation reaction. The latter mechanism is known to be a dominant mechanism for the photochemical reactions in homogeneous solutions.

Dai, Sheng; Metcalf, D.H.; Del Cul, G.D.; Toth, K.M. [Oak Ridge National Lab., TN (United States)] [Oak Ridge National Lab., TN (United States)

1996-12-18

185

Structure and spectroscopic properties of Er3+ doped germanate glass for mid-infrared application  

NASA Astrophysics Data System (ADS)

Intense 2.7 ?m emission derived from modified Er3+ doped germanate glass was reported. Raman spectrum analysis was carried out to grasp glass structure. Based on the absorption spectrum, the Judd-Ofelt parameters and radiative properties were calculated originated from Judd-Ofelt theory. 2.7 ?m emission characteristics, stark splitting features and energy transfer processes upon excitation of a conventional 808 nm or 980 nm laser diode were carefully investigated. The prepared glass possesses high spontaneous transition probability (34.28 s-1), large calculated emission cross section (13 × 10-21 cm2) and gain coefficient (5.4 cm-1) for the 4I11/2 ? 4I13/2 transition. These results indicate that Er3+ doped germanate glass has potential applications in mid-infrared lasers and amplifiers.

Wei, Tao; Chen, Fangze; Jing, Xufeng; Wang, Fengchao; Tian, Ying; Xu, Shiqing

2014-05-01

186

Thermal stability and spectroscopic properties of Er3+-doped antimony-borosilicate glasses.  

PubMed

This paper reports on the optical spectroscopic properties and thermal stability of Er3+-doped antimony-borosilicate glasses for developing 1.5 microm optical amplifiers. Upon excitation at 980 nm laser diode, an intense 1.5 microm infrared fluorescence has been observed with the maximum full width at half maximum (FWHM) of 90 nm for Er3+-doped antimony-borosilicate glasses. The emission cross-section and the lifetime of the 4I13/2 level of Er3+ ions are 6.3 x 10(-21) cm2 and 0.30 ms, respectively. It is noted that the product of the emission cross-section and FWHM of the glass studied is as great as 567 x 10(-21) cm2 nm, which is comparable or higher than that of bismuthate and tellurite glasses. PMID:18255334

Qian, Q; Zhao, C; Yang, G F; Yang, Z M; Zhang, Q Y; Jiang, Z H

2008-11-01

187

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

SciTech Connect

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.

Haro-Gonzalez, P.; Martin, I. R.; Arbelo-Jorge, E.; Gonzalez-Perez, S. [Departamento de Fisica Fundamental y Experimental, Electronica y Sistemas, Universidad de La Laguna, La Laguna, Tenerife 38206 (Spain); Caceres, J. M. [Departamento de Edafologia y Geologia, Universidad de La Laguna, La Laguna, Tenerife 38206 (Spain); Nunez, P. [Departamento de Quimica Inorganica, Universidad de La Laguna, La Laguna, Tenerife 38206 (Spain)

2008-07-01

188

Yb\\/Er-codoped and Yb-doped waveguide lasers in phosphate glass  

Microsoft Academic Search

We present experimental and theoretical results of our recent work on the development of waveguide lasers using rare-earth-doped phosphate glasses. An improvement has been achieved over previously reported waveguide laser results using the process of ion exchange in a commercially available Yb\\/Er-codoped phosphate glass composition. We have demonstrated slope efficiencies near 30% with output powers approaching 200 mW for 1540

David L. Veasey; David S. Funk; Philip M. Peters; Norman A. Sanford; Gregory E. Obarski; Norman Fontaine; Matt Young; Adele P. Peskin; Wei-Chih Liu; S. N. Houde-Walter; Joseph S. Hayden

2000-01-01

189

Properties and Applications of Laser-Induced Gratings in Rare Earth Doped Glasses.  

NASA Astrophysics Data System (ADS)

Scope and method of study. Four-wave-mixing techniques were used in an attempt to create permanent laser-induced grating in Pr^{3+}-, Nd ^{3+}-, Eu^ {3+}-, and Er^{3+ }-doped glasses. The permanent laser-induced grating signal intensity and build-up and erase times were investigated as function of the write beam crossing angle, write beam power, and temperature. Thermal lensing measurements were conducted on Eu^{3+} - and Nd^{3+}-doped glasses and room temperature Raman and resonant Raman spectra were obtained for Eu^{3+}-doped glasses. The permanent laser-induced grating signal intensity was studied in Eu^{3+} -doped alkali-metal glasses as a function of the alkali -metal network modifier ion and a model was developed by treating the sample as a two-level system. Optical device applications of the permanent laser-induced gratings were studied by creating some simple devices. Findings and conclusions. Permanent laser-induced gratings were created in the Pr^{3+ }- and Eu^{3+} -doped glasses. The permanent laser-induced grating is associated with a structural phase change of the glass host. The structural change is produced by high energy phonons which are emitted by radiationless relaxation processes of the rare earth ion. Nd^{3+} and Er^{3+} relax nonradiatively by the emission of phonons of much lower energy which are unable to produce the structural phase change needed to form a permanent laser-induced grating. The difference in energy of the emitted phonons is responsible for the differing characteristics of the thermal lensing experiments. The model does a good job of predicting the experimental results for the asymmetry and other parameters of the two-level system. The application of these laser -induced gratings for optical devices demonstrates their importance to optical technology.

Behrens, Edward Grady

190

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

SciTech Connect

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.

Fletcher, Luke B.; Witcher, Jon J.; Troy, Neil; Krol, Denise M. [Department of Applied Science, University of California Davis, Davis, California 95616 (United States); Reis, Signo T.; Brow, Richard K. [Department of Materials Science and Engineering, Missouri University of Science and Technology, Rolla, Missouri 65409 (United States)

2012-07-15

191

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

SciTech Connect

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.

Sontakke, Atul D.; Annapurna, K. [Glass Science and Technology Section, CSIR-Central Glass and Ceramic Research Institute, 196, Raja S. C. Mullick Road, Kolkata - 700 032 (India)

2012-07-01

192

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

NASA Astrophysics Data System (ADS)

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.

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

2014-07-01

193

Solitons in semiconductor-doped glass fibres with higher-order effects  

Microsoft Academic Search

We consider nonlinear wave propagation in a semiconductor-doped glass fibre. After the truncation of the saturated nonlinear equation, we obtain the envelope equation which consists of the higher-order effects like dispersion and self-steepening. The conditions for which the system admits soliton-type pulse propagation are investigated through the bilinear method. We also present the explicit soliton solutions.

K. Porsezian

1997-01-01

194

Single-step laser fabrication of refractive microlenses in semiconductor-doped glasses  

NASA Astrophysics Data System (ADS)

Exposure of semiconductor-doped glasses to above-band-gap focused cw laser radiation results in the controllable formation of microlenses. A laser-driven thermal runaway is proposed to explain the low powers required for the process. A linear array of eight identically prepared microlenses is characterized and shown to exhibit diffraction-limited performance.

Beadie, G.; Lawandy, N. M.

1995-11-01

195

Magnetism of spinel microcrystals in a Cr3+ -doped cordierite glass : an E. S. R. study  

E-print Network

1931 Magnetism of spinel microcrystals in a Cr3+ -doped cordierite glass : an E. S. R. study C that the structure of microcrystals is close to the MgCr2o4 spinel [1, 3]. After a heat treatment during a relatively spinel progressively built up, and a Article published online by EDP Sciences and available at http

Boyer, Edmond

196

Reversible nonlinear absorption in nanoporous glass polymer composite doped with functional dyes: experiment and background model  

NASA Astrophysics Data System (ADS)

The natural laws of the nonlinear absorption in the nanoporous glass polymer composite doped with phthalocyanine and porphyrin dyes is investigated experimentally using 24 nanosecond (FWHM) 532 nm laser pulses. The nonlinear absorption in the network of the four-level model is analyzed theoretically. It is demonstrated that theoretical result and experimental data have a good agreement.

Koldunov, L. M.; Koldunov, M. F.; Petuhov, A. V.; Sizuhin, A. V.

2010-09-01

197

Refractive index and density in F- and Cl-doped silica glasses  

SciTech Connect

The refractive index and density of fluorine- and chlorine-doped silica glasses were measured as functions of fictive temperature. The halogen concentrations were observed to have a refractive index or density that is independent of the fictive temperature were found. This implies that these properties are not affected by any heat-treatment conditions.

Kakiuchida, Hiroshi; Shimodaira, Noriaki; Sekiya, Edson H.; Saito, Kazuya; Ikushima, Akira J. [Research Center for Advanced Photon Technology, Toyota Technological Institute, 2-12-1 Hisakata, Tempaku, Nagoya, Aichi 468-8511 (Japan); Research Center for Advanced Photon Technology, Toyota Technological Institute, 2-12-1 Hisakata, Tempaku, Nagoya, Aichi 468-8511, Japan and Research Center, Asahi Glass Co., Ltd., 1150 Hazawa-cho, Kanagawa, Yokohama, Kanagawa 221-8755 (Japan); Research Center for Advanced Photon Technology, Toyota Technological Institute, 2-12-1 Hisakata, Tempaku, Nagoya, Aichi 468-8511 (Japan)

2005-04-18

198

Ce3+:YAG doped glass-ceramics for white light-emitting diode  

NASA Astrophysics Data System (ADS)

New types of phosphor (YAG:Ce3+: yttrium-aluminum garnet doped with Ce3+ ions) containing glass-ceramics material was developed for light-emitting diodes (LEDs). The optical properties of the experimental samples were investigated and are reported on. Use of new phosphor material in white LEDs fabricated with the "chip-on-board" technology is demonstrated.

Shvaleva, Maria A.; Nikulina, Lidiya A.; Aseev, Vladimir A.; Mynbaev, Karim D.; Bougrov, Vladislav E.; Kovsh, Alexey R.; Odnoblyudov, Maxim A.; Nikonorov, Nikolay V.; Romanov, Alexey E.

2014-09-01

199

Zeeman splitting and confinement effects in Er3+ -doped nano-glass-  

E-print Network

Zeeman splitting and confinement effects in Er3+ -doped nano-glass- ceramics in magnetic fields up into Zeeman doublet in external magnetic field. These effects make it possible to flatten the amplification perpendicular to the sample surface area, the Zeeman effect was observed parallel to the applied field. The PL

Moshchalkov, Victor V.

200

Bismuth-doped-glass optical fibers---a new active medium for lasers and amplifiers  

Microsoft Academic Search

Optical fibers with bismuth-doped silicate and germanate glass cores were fabricated by the modified chemical vapor deposition technique (solution and vapor-phase Bi incorporation). The fibers revealed an efficient luminescence with a maximum in the 1050-1200 nm spectral range, FWHM up to 200nm, and a lifetime of the order of 1ms.

V. V. Dvoyrin; V. M. Mashinsky; L. I. Bulatov; I. A. Bufetov; A. V. Shubin; M. A. Melkumov; E. F. Kustov; E. M. Dianov; A. A. Umnikov; V. F. Khopin; M. V. Yashkov; A. N. Guryanov

2006-01-01

201

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)

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-BT sintering and dielectric behavior.

Shahin, David I.

202

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

SciTech Connect

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.

Damas, Pedro [Departamento de Física, Faculdade de Ciências, Universidade do Porto, Rua do Campo Alegre, 687, 4169-007 Porto (Portugal)] [Departamento de Física, Faculdade de Ciências, Universidade do Porto, Rua do Campo Alegre, 687, 4169-007 Porto (Portugal); Coelho, João [INESC Porto, Rua do Campo Alegre, 687, 4169-007 Porto (Portugal)] [INESC Porto, Rua do Campo Alegre, 687, 4169-007 Porto (Portugal); Hungerford, Graham [HORIBA Jobin Yvon IBH Ltd., Skypark 5, 45 Finnieston Street, Glasgow G3 8JU (United Kingdom)] [HORIBA Jobin Yvon IBH Ltd., Skypark 5, 45 Finnieston Street, Glasgow G3 8JU (United Kingdom); Hussain, N. Sooraj, E-mail: nandyala.sooraj@fc.up.pt [Departamento de Física, Faculdade de Ciências, Universidade do Porto, Rua do Campo Alegre, 687, 4169-007 Porto (Portugal); INESC Porto, Rua do Campo Alegre, 687, 4169-007 Porto (Portugal)

2012-11-15

203

Tunable mid-infrared luminescence from Er(3+) -doped germanate glass.  

PubMed

Er(3+) -doped germanate glasses with superior thermal stability were prepared. Judd-Ofelt intensity parameters and important spectroscopic properties were discussed in detail. Upon 800 nm and 980 nm LD pumping, 2.7 µm fluorescence characteristics were investigated and it was found that the effective 2.7 µm emission bandwidth can reach to 101.79 nm in prepared glasses. The tunability of the 2.7 µm emission band can be realized by adjusting the Er(3+) content. Moreover, a high-emission cross-section (11.09 ×10(-21) cm(2) ), large gain bandwidth (772.30 ×10(-28) cm(3) ) and gain coefficient (6.72 cm(-1) ) were obtained in the prepared sample. Hence, Er(3+) -doped germanate glass might be a promising mid-infrared material for tunable amplifiers or lasers. Copyright © 2014 John Wiley & Sons, Ltd. PMID:25408330

Li, Bingpeng; Wei, Tao; Tian, Ying; Jing, Xufeng; Chen, Fangze; Wang, Fengchao; Zhang, Junjie; Cai, Muzhi; Xu, Shiqing

2014-11-19

204

Emission properties of heavy metal oxide glasses doped with rare-earths  

NASA Astrophysics Data System (ADS)

Emissions at 1.3?m and mid-infrared region from several rare-earths ions doped into PbO-Bi2O3-Ga2O3 glasses were investigated. Lifetime of the Pr3+:1G4 level was 53´s with a quantum efficiency of 9%. Emission at 2.73?m from Er3+, which is normally quenched in oxide glass, was evident and the lifetime of the upper emission level was approximately 900´s. Thermal stability of PbO-Bi2O3-Ga2O3 glass was considerably improved by adding 10 mole % of GeO2. Doping of Tm3+ and Ho3+ showed potentials for S-band fiber-optic amplification.

Heo, Jong

2003-07-01

205

Nitrogen-ion-implanted planar optical waveguides in Er-doped tellurite glass: fabrication and characterization  

NASA Astrophysics Data System (ADS)

Fabrication of channel waveguides in Er-doped tungsten-tellurite glasses was recently demonstrated. In order to get a deeper understanding of the process and to optimize the characteristics of the waveguides, we fabricated a set of planar waveguides, each of 7 mm × 7 mm lateral dimensions, in an Er-doped tellurite glass sample by implantation of 1.5 MeV nitrogen ions. Doses of the implanting ions ranged from 1 Â. 10 16 to 8 Â. 10 16 ions/cm2. The samples were studied using interference phase contrast microscopy (Interphako), m-line spectroscopy and spectroscopic ellipsometry. The results show that a barrier layer of reduced refractive index was created around the range of the implanted ions at every dose. It is hoped that combination of the results obtained in these experiments with simulations for channel waveguides will make it possible to optimize ion-implanted fabrication of integrated optical components in this tellurite glass.

Bányász, I.; Berneschi, S.; Cacciari, I.; Fried, M.; Lohner, T.; Nunzi-Conti, G.; Pászti, F.; Pelli, S.; Petrik, P.; Righini, G. C.; Watterich, A.; Zolnai, Z.

2008-02-01

206

Monte Carlo simulation of radiation pattern for rare earth ions doped luminescent glasses under violet LED excitation  

NASA Astrophysics Data System (ADS)

Rare earth ions doped luminescence glasses are promising phosphor candidates in the fabrication of LEDs in the future due to their specific advantages such as higher thermal stability, higher transparency, compared to current commercial LEDs. While radiation patterns of luminescent glasses are different from current commercial LEDs fabricated by phosphors, luminescent glasses play roles both in emitting light and adjusting light distribution. In order to investigate radiation pattern of luminescent glasses, luminescence physical model of flat glasses doped with single rare earth ion was presented. Process of photons acting on rare earth ions and transporting in the luminescent glasses, and output light distribution from luminescent glasses were analyzed based on violet LED. At last, the simulating of radiation pattern for luminescent glasses based on Monte Carlo ray-tracing method was proved by experiment.

Lei, Xiaohua; Feng, Yong'an; Chen, Weimin; Zhang, Peng; Ren, Linjiao; Du, Xiaoqing

2013-09-01

207

Bioactive glass in tissue engineering  

PubMed Central

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

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

2011-01-01

208

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

PubMed

Structural, spectroscopic and thermal properties of SiO?-Al?O?-Sb?O?-Na?O glass system doped with 0.2 mol% Tm?O? 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 SiO?/Sb?O? 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 ?m corresponding to (3)F??(3)H? 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. PMID:25049172

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

2015-01-01

209

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

NASA Astrophysics Data System (ADS)

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 Tm3+ 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 ?m corresponding to 3F4 ? 3H6 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.

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

2015-01-01

210

Nd3+ doped CAS glasses: A thermo-optical and spectroscopic investigation  

NASA Astrophysics Data System (ADS)

Previous works have showed that calcium aluminosilicate (CAS) glasses, when prepared under vacuum conditions, are good candidates for solid state laser medium hosts and optical devices due to their appropriated thermal, optical and mechanical properties. These promising results led us to investigate the thermo-optical properties and emission spectra as a function of temperature in Nd3+ doped CAS glasses. Temperature changes in optical systems can cause structural modifications to the host, as well as other effects, such as emission quenching, or self-focalization. In this work, two series of CAS glasses, doped up to 5 wt.% Nd2O3, were prepared and characterized. Measurements of thermal coefficient of optical path length (dS/dT) and emission were performed on both series of Nd3+ doped CAS. In addition, measurements of optical absorption coefficient and emission lifetime were carried out. The results are discussed in terms of temperature dependence of these properties and Nd2O3 content. Comparisons with other glasses, such as LSCAS (low-silica calcium aluminosilicate) are also presented.

Steimacher, A.; Barboza, M. J.; Pedrochi, F.; Astrath, N. G. C.; Rohling, J. H.; Baesso, M. L.; Medina, A. N.

2014-11-01

211

Spectroscopic properties of bismuth-germanate glasses co-doped with erbium and holmium ions  

NASA Astrophysics Data System (ADS)

In the article an analysis of thermal and spectroscopic properties of heavy metal oxide glasses from the Bi2O3-Ga2O3- Na2O-Ge2O3 system doped with rare earth elements were presented. It has been focused on the elaboration of the glass composition in terms of low phonon energy, high transparency in the range of infrared region and high thermal stability (?T=160 °C) required in optical fiber technology. Fabricated glasses co-doped with Er3+/Ho3+ions under 980 nm laser diode excitation exhibit emission at 1.55 ?m (Er3+: 4I 13/2 ? 4I15/2) and 2.0 ?m (Ho3+: 4I7 ? 5I8). The emission at 2.0 ?m results from the Er3+ ? Ho3+energy transfer. Taking into account great thermal stability and good optical properties such as high transparency (up to 80%) or high refractive index (2.23), the fabricated bismuth-germanate glass co-doped with Er3+/Ho3+ is promising material for construction of active optical fibers operating in the range of mid-infrared.

Ragin, Tomasz; Kochanowicz, Marcin; ?mojda, Jacek; Dorosz, Dominik

2014-05-01

212

Spectroscopic properties and energy transfer in Er-Tm co-doped bismuth silicate glass  

NASA Astrophysics Data System (ADS)

In this paper, we investigate the spectroscopic properties of and energy transfer processes in Er-Tm co-doped bismuth silicate glass. The Judd-Ofelt parameters of Er3+ and Tm3+ are calculated, and the similar values indicate that the local environments of these two kinds of rare earth ions are almost the same. When the samples are pumped at 980 nm, the emission intensity ratio of Tm:3F4 ? 3H6 to Er:4I13/2 ? 4I15/2 increases with increased Er3+ and Tm3+ contents, indicating energy transfer from Er:4I13/2 to Tm:3F4. When the samples are pumped at 800 nm, the emission intensity ratio of Er:4I13/2 ? 4I15/2 to Tm:3H4 ? 3F4 increases with increased Tm2O3 concentration, indicating energy transfer from Tm:3H4 to Er:4I13/2. The rate equations are given to explain the variations. The microscopic and macroscopic energy transfer parameters are calculated, and the values of energy transfer from Er:4I13/2 to Tm:3F4 are found to be higher than those of the other processes. For the Tm singly-doped glass pumped at 800 nm and Er-Tm co-doped glass pumped at 980 nm, the pumping rate needed to realize population reversion is calculated. The result shows that when the Er2O3 doping level is high, pumping the co-doped glass by a 980 nm laser is an effective way of obtaining a low-threshold ˜2 ?m gain.

Wang, Xin; Li, Zhilan; Li, Kefeng; Zhang, Lei; Cheng, Jimeng; Hu, Lili

2013-10-01

213

X-ray absorption (XANES) and photoelectron spectroscopy (XPS) of gamma irradiated Nd doped phosphate glass  

E-print Network

This paper presents the X-ray absorption near edge structure (XANES) and X-ray photoelectron spectroscopic (XPS) studies of Nd doped phosphate glasses before and after gamma irradiation. The intensity and location of LIII edge white line peak of Nd are found to be dependent on the concentration of Nd as well as on the ratio of O/Nd in the glass matrix. The decrease in the peak intensity of white line of XANES spectra and asymmetry in the profile of Nd 3d5/2 peak of XPS after gamma irradiation clearly indicates that Nd3+ gets reduced to Nd2+ in the glass matrix, which increases with an increase in the doses of irradiation. Sharpening of Nd 3d5/2 XPS profile indicates about the deficiency of oxygen in the glass after gamma irradiation, which is supported by EDX measurement.

Rai, V N; Jha, S N; Bhattacharya, D; Shekhar, B N Raja

2015-01-01

214

Interstitial BiO molecule as a center of broadband IR luminescence in bismuth-doped silica glass  

E-print Network

IR luminescence and absorption in bismuth-doped silica glass-core fibers observed recently (see [arXiv:1106.2969v1 [physics.optics]) are argued to be caused by transitions in interstitial BiO molecules

Sokolov, V O; Dianov, E M

2011-01-01

215

Cobalt-doped transparent glass ceramic as a saturable absorber q switch for erbium:glass lasers.  

PubMed

A new saturable absorber Q switch for 1.54-mum Er:glass lasers is presented. The saturable absorber is a transparent glass ceramic that contains magnesium-aluminum spinel nanocrystallites doped with tetrahedrally coordinated Co(2+) ions. We obtained Q-switched pulses of up to 5.5 mJ in energy and 80 ns in duration at 1.54 mum. The relaxation time of (4)A(2) ?(4)T(1)((4)F) transition bleaching was measured to be (450 ? 150) ns. Ground-state and excited-state absorption cross sections at 1.54-mum wavelength were estimated to be (3.2 ? 0.4) x 10(-19) cm(2) and (5.0 ? 0.6) x 10(-20) cm(2), respectively. PMID:18360471

Malyarevich, A M; Denisov, I A; Yumashev, K V; Dymshits, O S; Zhilin, A A; Kang, U

2001-08-20

216

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

NASA Astrophysics Data System (ADS)

Optically active glass-ceramics (GC) with the low-phonon phases of fluorides, doped with Er3+ 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 4S3/2 and 4F9/2 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.

?roda, Marcin; Szlósarczyk, Krzysztof; Ró?a?ski, Marek; Sitarz, Maciej; Jele?, Piotr

2015-01-01

217

Copper doping of silicate glasses by the ion-exchange technique: A photoluminescence spectroscopy study  

NASA Astrophysics Data System (ADS)

Copper-alkali ion exchange is used for doping superficial layers of different silicate glasses (commercial soda-lime and BK7) with copper ions. Spectroscopic and time-resolved photoluminescence properties of the obtained systems are studied in the range of 80-294 K. Analysis indicates the presence of Cu+ ions located in distorted octahedral sites, and a different position of the triplet electronic levels for the two glass matrices. The luminescence decay-time signal is simulated by a biexponential behavior, interpreted on the basis of a four-level scheme.

Borsella, E.; Dal Vecchio, A.; Garc?Ì?a, M. A.; Sada, C.; Gonella, F.; Polloni, R.; Quaranta, A.; van Wilderen, L. J. G. W.

2002-01-01

218

Erbium-doped glasses for fiber amplifiers at 1500 nm  

Microsoft Academic Search

Material-dependent properties influencing the performance of fiber amplifiers are reviewed together with the available data for Er3+ . The major glass types potentially useful in this application are considered and compared to silica. The topics addressed include quenching processes and the solubility of rare-earth ions, transition strengths and bandwidths at the 1500-nm gain transition, and the characteristics at the 800-,

William J. Miniscalco

1991-01-01

219

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

NASA Technical Reports Server (NTRS)

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.

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

1991-01-01

220

Silver nanoparticles enhanced luminescence properties of Er3+ doped tellurite glasses: Effect of heat treatment  

NASA Astrophysics Data System (ADS)

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 ?m band broad and high-gain erbium-doped fiber amplifiers.

Fares, Hssen; Elhouichet, Habib; Gelloz, Bernard; Férid, Mokhtar

2014-09-01

221

Quantum efficiency and excited-state relaxation dynamics in neodymium-doped phosphate laser glasses  

Microsoft Academic Search

Radiometrically calibrated spectroscopic techniques employing an integrating-sphere detection system have been used to determine the fluorescence quantum efficiencies for two commercially available Nd{sup 3+}-doped phosphate laser glasses, LG-750 and LG-760. Quantum efficiencies and fluorescence lifetimes were measured for samples with various neodymium concentrations. It is shown that the effects of concentration quenching are accurately described when both resonant nonradiative excitation

J. A. Caird; A. J. Ramponi; P. R. Staver

1991-01-01

222

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

SciTech Connect

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.

Morrell, B.; Okada, G.; Vahedi, S.; Koughia, C., E-mail: cyril.koughia@usask.ca; Kasap, S. O. [Department of Electrical and Computer Engineering, University of Saskatchewan, Saskatoon, Saskatchewan S7N 5C9 (Canada); Edgar, A.; Varoy, C. [School of Chemical and Physical Sciences and MacDiarmid Institute, Victoria University of Wellington, Wellington 6140 (New Zealand); Belev, G.; Wysokinski, T.; Chapman, D. [Canadian Light Source, Inc., University of Saskatchewan, Saskatoon, Saskatchewan S7N 5C9 (Canada); Sammynaiken, R. [Saskatchewan Structural Sciences Centre, University of Saskatchewan, 110 Science Place, Saskatoon, Saskatchewan S7N 5C9 (Canada)

2014-02-14

223

Up-conversion visible emission in rare-earth doped fluoride glass waveguides  

NASA Astrophysics Data System (ADS)

The paper presents the visible emissions through frequency up-conversion and energy transfer process in the waveguide rare-earth (RE) codoped with RE/Yb (RE=Er, Pr, Tm), as well as physical properties of fluoride glasses and their fabrication par physical vapor deposition. The RE doping is made by substituting LaF in the base ZLAG glass composition (70%ZrF4-23.5%LaF3-0.5%AlF3-6%GaF3). Under 980-nm excitation, the emissions in planar waveguides of 2 to 3 thickness are found similar to the ones observed in bulk; blue and red emissions for 0.5Pr/xYb codoping and blue emission for 0.75Tm/xYb codoping with x ranging from 1 to 5 mol%. The bulk glass doped with Er/Tm/Yb can generate simultaneously and with high efficiency red-green-blue emissions from single-wave pumping at 980 nm. These preliminary results show that Er/Tm/Yb triply doped ZLA waveguide is a potential material for compact white light sources.

Boulard, Brigitte; Dieudonné, Belto; Gao, Youping; Chiasera, Alessandro; Ferrari, Maurizio

2014-07-01

224

Cu(2+)-doped germano-silicate glass fiber with high resonant nonlinearity.  

PubMed

We firstly report on the fabrication of Cu(2+)-doped germano-silicate glass fiber for nonlinear optical devices application by using modified chemical vapor deposition and solution doping processes. Broadband absorption near 700nm due to the 3d-shell electron transitions of Cu(2+) ions from the ground state to the excited states was observed. The resonant nonlinearity of the Cu(2+)-doped fiber was estimated to be 5.5x10(-17)m(2)/W by measuring the phase shift of the fringes obtained from the long-period fiber grating pair upon pumping with a laser diode at 980nm and non-resonant nonlinearities were also measured to be 4.114x10(-21)m(2)/W by the continuous wave self-phase modulation method. PMID:19532611

Lin, Aoxiang; Kim, Bok Hyeon; Moon, Dae Seung; Chung, Youngjoo; Han, Won-Taek

2007-04-01

225

Structure and properties of strontium-doped phosphate-based glasses  

PubMed Central

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

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

226

Blue, green and 0.8 ?m Tm 3+, Ho 3+ doped upconversion laser glasses, sensitized by Yb 3+  

Microsoft Academic Search

To obtain efficient upconversion laser glass, the optical properties of Tm3+ and Ho3+ were investigated in various glasses. Fluoride glass was selected as base glass for upconversion. The efficient upconversion fluorescences corresponding to the 1G4?3H6 and 3H4?3H6 transitions of Tm3+ and the 5S2?5I8 transition of Ho3+ were observed in Yb3+-Tm3+ and Yb3+-Ho3+ doped aluminozircofluoride glasses excited at 980 nm. The

Bo Peng; Tetsuro Izumitani

1995-01-01

227

Fabrication of uniformly dispersed nanoparticle-doped chalcogenide glass  

NASA Astrophysics Data System (ADS)

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.

Lu, Chao; Almeida, Juliana M. P.; Yao, Nan; Arnold, Craig

2014-12-01

228

Optical and structural properties of WO3-doped silicophosphate glasses for gamma-ray applications  

NASA Astrophysics Data System (ADS)

Optical and FTIR spectral measurements were carried out for prepared base undoped sodium silicophosphate glass together with samples of the same composition containing (0.5%, 0.75%, 1% and 1.25%) WO3 in order to characterize the valence states of tungsten ions in such host mixed forming oxides glass. The same combined spectral studies were repeated after subjecting the prepared samples to gamma irradiation with a dose of 8 M rad (8 × 104 Gy). The base undoped glass exhibits a strong UV absorption band which is related to the presence of unavoidable trace iron (Fe3+) ions impurities contaminated within the raw materials used for the preparation of the base glass. WO3-doped glasses exhibit bluish color and reveal distinct optical absorption peaks which are attributed to the presence of both W6+ and W5+ ions. Infrared absorption spectra of the studied glasses reveal distinct broad IR bands which are attributed to the sharing modes of vibrations of both phosphate and silicate networks. The addition of the dopants (0.5-1.25%) WO3 did not cause marked changes in the IR spectral vibrational bands. Gamma irradiation conducts no variations in the number or position of main IR characteristic absorption bands due to the stability of the glassy network containing combined structural building groups together with the presence of tungsten ions. E.S.R. spectra of WO3-samples reveal spin resonance indicating the presence of unpaired tungsten ions and support the optical result.

Marzouk, M. A.; Hamdy, Y. M.; ElBatal, H. A.

2014-01-01

229

FTIR spectra and thermal properties of TiO2-doped iron phosphate glasses  

NASA Astrophysics Data System (ADS)

Structure and thermal properties of xTiO2·(90 - x) (60P2O5-40Fe2O3)?10CaF2 (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.

Lu, Mingwei; Wang, Fu; Liao, Qilong; Chen, Kuiru; Qin, Jianfa; Pan, Sheqi

2015-02-01

230

Fabrication and characterization of channel optical waveguides in Er/Yb-doped silicate glasses  

NASA Astrophysics Data System (ADS)

Here we report on a set of newly designed silicate glasses doped with erbium and ytterbium, which appear to be promising materials for waveguide optical amplifiers. Properties of these glasses relevant for the fabrication of optical waveguides by ion exchange (permeability for ions to be exchanged) and dispersion characteristics of fabricated waveguides are compared to other types of silicate glass commonly used for this purpose, namely the boro-silicate (BK7) and soda-lime (GIL49) glasses. Planar and channel optical waveguides were fabricated in all these glasses by Ag + ? Na + and K + ? Na + ion exchanges. Fabrication process was adjusted for each particular glass substrate individually and was optimized to obtain single-mode channel waveguides at the wavelength of 1550 nm with optical mode field distributions providing highly efficient coupling to a standard single-mode optical fiber. Chemical composition of the fabricated waveguiding layers was determined by scanning electron microscopy (SEM-EDAX). Optical properties of the waveguides were characterized by a standard dark mode spectroscopy at the wavelength of 671 nm and by near field imaging in the spectral range from 1500 to 1640 nm.

Ondrá?ek, František; Salavcová, Linda; Míka, Martin; Lahodný, František; Slavík, Radan; Špirková, Jarmila; ?tyroký, Ji?í

2007-11-01

231

Extruded channel waveguides in a neodymium-doped lead-silicate glass for integrated optic applications  

NASA Astrophysics Data System (ADS)

We report on the development of channel waveguides in a lead-silicate glass through the extrusion technique. An extruded glass slab with four imbedded fibers each with core size of 8 by 2.5 ?m in the horizontal and vertical directions was manufactured. These neodymium-doped channel waveguides were in single-mode operation at 808 nm and had attenuation of 0.1 dB cm-1 at 1.06 ?m. The measured 4F3/2 lifetime of 488 ?s and emission cross section of 2.5×10-20 cm2 were in good agreement with reported values. The integration of multiple glass variants into a single compact platform is presented as a manufacturing route for complex integrated optical waveguides.

Mairaj, Arshad K.; Feng, Xian; Hewak, Daniel W.

2003-10-01

232

Structure and optical properties of rare earth-doped zinc oxyhalide tellurite glasses  

SciTech Connect

Zinc tellurite glasses appear to be excellent candidates for hosting rare earth ions since they provide a low phonon energy environment to minimize non-radiative losses as well as possess good chemical durability and optical properties. The optical behavior of the rare earth ion can be manipulated by modifying its local environment in the glass host. The authors report measurements of the emission lifetime, optical absorption, and vibrational density of states of the glass system (ZnO){sub x}(ZnF{sub 2}){sub y}(TeO{sub 2}){sub 1{minus}x{minus}y}doped (0.1 mol%) with a series of rare earths. Phonon sideband spectroscopy has been successfully employed to probe vibrational structure in the immediate vicinity of the rare earth ion. The authors observe a significant increase in the emission lifetime (from approximately 150 {mu}s to 250 {mu}s) of Nd{sup 3+} with increasing fluorine substitution.

Sidebottom, D.L.; Hruschka, M.A. [Univ. of New Mexico, Albuquerque, NM (United States). Dept. of Chemical and Nuclear Engineering; Potter, B.G.; Brow, R.K. [Sandia National Labs., Albuquerque, NM (United States)

1997-10-01

233

Photosensitivity of ion-exchanged Er-doped phosphate glass using 248nm excimer laser radiation  

NASA Astrophysics Data System (ADS)

The photosensitivity to 248nm excimer laser radiation of Er-doped Schott IOG-1 phosphate glass is presented. The photosensitive mechanism is investigated by employing a grating recording process. Index changes of up to ~2.0x10-3 were measured in silver ion-exchanged samples using diffraction efficiency measurements; whereas changes of only ~10-5 were measured for non-ion-exchanged samples. Absorption measurements allowed the identification of specific color center bands, which were attributed to the glass matrix and to the silver ions. Investigation of the exposed ion-exchanged glass using scanning electron microscopy and energy dispersive x-ray microanalysis revealed that in addition to the color centers formed, silver ion migration and ionization contribute significantly to the UV-induced index changes

Pissadakis, Stavros; Ikiades, Aris; Hua, Ping; Sheridan, Anna K.; Wilkinson, James S.

2004-07-01

234

Photosensitivity of ion-exchanged Er-doped phosphate glass using 248nm excimer laser radiation.  

PubMed

The photosensitivity to 248nm excimer laser radiation of Er-doped Schott IOG-1 phosphate glass is presented. The photosensitive mechanism is investigated by employing a grating recording process. Index changes of up to ~2.0x10(-3) were measured in silver ion-exchanged samples using diffraction efficiency measurements; whereas changes of only ~10(-5) were measured for non-ion-exchanged samples. Absorption measurements allowed the identification of specific color center bands, which were attributed to the glass matrix and to the silver ions. Investigation of the exposed ion-exchanged glass using scanning electron microscopy and energy dispersive x-ray microanalysis revealed that in addition to the color centers formed, silver ion migration and ionization contribute significantly to the UV-induced index changes. PMID:19483833

Pissadakis, Stavros; Ikiades, Aris; Hua, Ping; Sheridan, Anna; Wilkinson, James

2004-07-12

235

Ytterbium fibre laser with a heavily Yb{sup 3+}-doped glass fibre core  

SciTech Connect

The use of optical fibres with a high concentration of active ions in the fibre core allows the reduction of the active fibre length and the increase in the threshold powers of various nonlinear effects in the fibre, thereby increasing the maximum output power of fibre lasers. For this purpose, we manufactured a highly concentrated ytterbium-doped ({approx}1.0x10{sup 21}cm{sup -3}) phosphate glass for the active fibre core and a pure glass of a similar composition for the fibre cladding. A single-mode fibre is fabricated from these glasses and generation is obtained in an ytterbium laser based on this fibre with the slope efficiency of no less than 60% at a wavelength of 975 nm. (letters)

Bufetov, Igor' A; Semenov, S L; Kosolapov, A F; Mel'kumov, Mikhail A; Dudin, V V; Dianov, Evgenii M [Fiber Optics Research Center, Russian Academy of Sciences, Moscow (Russian Federation); Galagan, B I; Denker, B I; Osiko, Vyacheslav V; Sverchkov, S E [Laser Materials and Technology Research Center, A. M. Prokhorov General Physics Institute, Russian Academy of Sciences, Moscow (Russian Federation)

2006-03-31

236

Optical properties, fluorescence mechanisms and energy transfer in Tm 3+, Ho 3+ and Tm 3+ Ho 3+ doped near-infrared laser glasses, sensitized by Yb 3+  

Microsoft Academic Search

The optical properties of the rare elements Tm3+, Ho3+ and Yb3+ were systematically investigated in various glasses. The Tm3+ doped aluminozircofluoride glass shows higher quantum efficiency, longer lifetime and stronger fluorescence intensity than Tm3+ doped YSGG crystal and other Tm3+ doped glasses for the 3H4 ? 3H6 transition. Similar quantum efficiency, longer lifetime and stronger fluorescence intensity were also found

B. Peng; Tetsuro Izumitani

1995-01-01

237

White light simulation and luminescence studies on Dy3+ doped Zinc borophosphate glasses  

NASA Astrophysics Data System (ADS)

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.

Vijayakumar, R.; Venkataiah, G.; Marimuthu, K.

2015-01-01

238

Mössbauer spectroscopy of europium-doped fluorochlorozirconate glasses and glass ceramics: optimization of storage phosphors in computed radiography  

PubMed Central

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

Pfau, C; Paßlick, C; Gray, S; Johnson, JA; Johnson, CE; Schweizer, S

2013-01-01

239

Preparation and characterization of silver-doped nanobioactive glass particles and their in vitro behaviour for biomedical applications.  

PubMed

In this study, silver-doped silica- and phosphate-based nanobioactive glass compositions (58SiO2-(33- x)CaO-9P2O5-xAg2O) (x = 0, 0.5, 1, 2 and 3 mol%) were synthesised by a simple and cost-effective sol-gel method. The prepared samples were characterised by X-ray diffraction, Fourier transform infrared spectroscopy, transmission electron microscopy, scanning electron microscopy and energy-dispersive X-ray fluorescence spectrometer studies. All the compositions of the glass samples revealed amorphous phase with spherical morphology and a particle size less than 100 nm. The prepared glass samples reveal the specific surface area in the range of 55.31-90.69 m2 g(-1). The bioactivity of glass samples was confirmed through the formation of the hydroxyapatite layer on glass surfaces during in vitro studies in which silver doped glasses (2 and 3 mol%) showed better bioactivity. A better biocompatibility was achieved in human gastric adenocarcinoma cell line in case of silver-free glass sample while comparing the biological behaviour of Ag2O-doped glasses. Further, the Ag2O-doped nanobioactive glasses revealed significant antibacterial activity against Staphylococcus aureus and Escherichia coli. Ag2O substitutions showed better in vitro bioactivity and remained slightly toxic to human cells at a concentration of 100 microg mL(-1). Silver-doped nanobioactive glass shows good antimicrobial property as well as no significant toxic for implant applications. PMID:23882760

Prabhu, Muthusamy; Kavitha, Kandiah; Suriyaprabha, Rangaraj; Manivasakan, Palanisamy; Rajendran, Venkatachalam; Kulandaivelu, Palanisami

2013-08-01

240

Diffractive optical element embedded in silver-doped nanocomposite glass.  

PubMed

A diffractive optical element is fabricated with relative ease in a glass containing spherical silver nanoparticles 30 to 40 nm in diameter and embedded in a surface layer of thickness ~10 ?m. The nanocomposite was sandwiched between a mesh metallic electrode with a lattice constant 2 ?m, facing the nanoparticle containing layer and acting as an anode, and a flat metal electrode as cathode. Applying moderate direct current electric potentials of 0.4 kV and 0.6 kV at an elevated temperature of 200 °C for 30 minutes across the nanocomposites led to the formation of a periodic array of embedded structures of metallic nanoparticles. The current-time dynamics of the structuring processes, optical analyses of the structured nanocomposites and diffraction pattern of one such fabricated element are presented. PMID:23037407

Fleming, Lauren A H; Wackerow, Stefan; Hourd, Andrew C; Gillespie, W Allan; Seifert, Gerhard; Abdolvand, Amin

2012-09-24

241

Optical and luminescent properties of Sm³+ doped tellurite glasses.  

PubMed

Glasses with chemical composition of (62-x) TeO(2)+25 ZnO+8 K(2)O+5 CaO+x Sm(2)O(3) (TZKCSmx; x=0.1, 0.5, 1.0, 1.5 mol%) were prepared by melt quenching technique. The absorption spectrum was recorded in the UV-visible and NIR regions. The oscillator strengths of absorption bands were obtained by measuring the area under the bands. Judd-Ofelt analysis has been carried out to estimate the host dependent J-O intensity ?(?) (?=2, 4, 6) parameters by least squares fitting approach. Photoluminescence spectra recorded in the visible region revealed intense green, orange and red emission bands in all the glasses, corresponding to the (4)G(5/2)?(6)H(5/2), (4)G(5/2)?(6)H(7/2) and (4)G(5/2)?(6)H(9/2) transitions respectively. From the emission spectra and J-O intensity parameters, various radiative parameters were calculated from the excited (4)G(5/2) to the lower lying (6)H(J) (J=5/2, 7/2, 9/2, 11/2) multiplet. Quenching of luminescence with the increase of Sm(3+) ions concentration has been observed. Decay times of excited (4)G(5/2) state decrease with the increase of the Sm(3+) ions concentration. The energy transfer mechanism that leads to the quenching of (4)G(5/2) state lifetime has been discussed. Inokuti-Hirayama (I-H) model was used to evaluate various energy transfer parameters, which are the qualitative indicators for the interaction among Sm(3+) ions. PMID:23274475

Sasikala, T; Rama Moorthy, L; Mohan Babu, A

2013-03-01

242

Synthesis, characterization and processing of active rare earth-doped chalcohalide glasses  

NASA Astrophysics Data System (ADS)

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 resulting fiber verified the constituents of the fiber. Due to tradeoffs between thermal properties, optical properties and rare earth solubility, the Ge-Se-I glass system must still be optimized prior to use as an active fiber device. Nevertheless, the viability of this host system has been demonstrated in this investigation. Some very promising advantages to adding halides to chalcogenide glass systems have been confirmed, including the tailoring of glass transition temperatures, enhancement of rare earth solubility, expanded fluorescence emissions in the IR, and suppression of some impurity absorption bands. Also, the potential for rod-and-tube fiberization utilizing the rotational casting method for tube synthesis has been established along with its resulting pristine core-clad interface. This research provides a foundation for active fiber device applications in the 2 to 10 mum spectral region.

Debari, Roberto Mauro

243

Spectroscopic properties of Ho3+, Tm3+, and Ho3+/Tm3+ doped tellurite glasses for fiber laser applications  

NASA Astrophysics Data System (ADS)

Several papers were reported on spectroscopic properties of rare earth doped different host glasses. A complete knowledge of fluorescence properties of rare earth ions in laser materials is necessary to achieve efficient, compact and cheap sources of laser radiation for NIR and mid-IR region. Tellurite glasses are potentially useful for generation of NIR and mid-IR laser radiation due to its special features such as lowest phonon energy (750 cm-1) among oxide glasses, reasonably wide transmission region (0.35 - 5?m), good glass stability, good rare earth ion solubility, high linear and non-linear refractive index. In the present work, authors prepared Ho3+ and Tm3+ singly doped and Ho3+/Tm3+ co-doped tellurite glasses using conventional melt-quenching method. Spectroscopic measurements and analysis of energy transfer process in Ho3+, Tm3+ and Ho3+ /Tm3+ co-doped glasses pumped with 785nm and 451 nm excitation wavelengths have been performed. There are some spectroscopic properties which are important in understanding and modeling of rare earth doped laser materials. Using Judd-Ofelt theory, radiative transition rates (Arad), radiative lifetimes (?R) and branching ratios (?) were estimated for certain excited states of Ho3+ and Tm3+ doped tellurite glasses. The emission cross-sections and gain coefficients have been determined from the absorption spectra of Ho3+ and Tm3+ ions in tellurite glasses. The energy transfer process such as ion cross-relaxation, Tm3+-Ho3+ energy transfer and energy transfer upconversion were studied and identified to specific candidate for laser operation.

Seshadri, M.; Ferencz Junior, J. A. P.; Ratnakaram, Y. C.; Barbosa, L. C.

2014-03-01

244

Evidence of phase transition in Nd3+ doped phosphate glass determined by thermal lens spectrometry.  

PubMed

Thermal lens spectroscopy (TLS), differential scanning calorimetry (DSC) and Fourier transform infrared (FTIR) techniques were applied to the thermo-optical property analysis of a new phosphate glass matrix PANK with nominal composition 40P2O5·20Al2O3·35Na2O·5K2O (mol%), doped with different Nd(3+) compositions. This glass system, synthesized by the fusion protocol, presents high transparency from UV to the near infrared, excellent thermo-optical properties at room temperature and high fluorescence quantum efficiency. Thermal lens phase shift parameters, thermal diffusivity and the DSC signal present pronounced changes at about 61 °C for the PANK glass system. This anomalous behavior was associated with a phase transition in the nanostructured glass materials. The FTIR signal confirms the presence of isolated PO4 tetrahedron groups connected to different cations in PANK glass. As a main result, our experimental data suggest that these tetrahedron groups present a structural phase transition, paraelectric-ferroelectric phase transition, similar to that in potassium dihydrogen phosphate, KH2PO4, nanocrystals and which TLS technique can be used as a sensitive method to investigate changes in the structural level of nanostructured materials. PMID:24310914

Andrade, Acácio A; Lourenço, Sidney A; Pilla, Viviane; Silva, Anielle C Almeida; Dantas, Noelio O

2014-01-28

245

Optical absorption and photoluminescence properties of Nd3+ doped mixed alkali phosphate glasses-spectroscopic investigations.  

PubMed

Spectroscopic investigations were performed on 68NH(4)H(2)PO(4).xLi(2)CO(3)(30-x)K(2)CO(3) and 68NH(4)H(2)PO(4).xNa(2)CO(3)(30-x)K(2)CO(3) (where x=5, 10, 15, 20 and 25) glasses containing 2 mol% Nd(2)O(3). Various spectroscopic parameters (Racah (E(1), E(2), E(3)), spin-orbit (xi(4f)) and configuration interaction (alpha)) are reported. Judd-Ofelt intensity parameters (Omega(2), Omega(4), Omega(6)) are calculated for Nd(3+) doped two mixed alkali phosphate glass matrices. From the magnitude of Judd-Ofelt parameters, covalency is studied as a function of x in the glass matrix. Using Judd-Ofelt intensity parameters, total radiative transition probabilities (A(T)), radiative lifetimes (tau(R)), branching ratios (beta) and integrated absorption cross sections (Sigma) have been computed for certain excited states of Nd(3+) in these mixed alkali phosphate glasses. Emission cross sections (sigma(P)) are calculated for the two transitions, (4)G(7/2)-->(4)I(11/2) and (4)G(7/2)-->(4)I(13/2) of Nd(3+) in these mixed alkali phosphate glasses. Optical band gaps (E(opt)) for direct and indirect transitions are reported. PMID:19010718

Ratnakaram, Y C; Srihari, N V; Kumar, A Vijaya; Naidu, D Thirupathi; Chakradhar, R P S

2009-02-01

246

Intense 1.6 ?m fluorescence of Nd{sup 3+} doped cadmium bismuth silicate glasses  

SciTech Connect

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 (?{sub 2}, ?{sub 4}, ?{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.

Pal, I., E-mail: ip-gjust@yahoo.com; Agarwal, A., E-mail: ip-gjust@yahoo.com; Sanghi, S., E-mail: ip-gjust@yahoo.com [Department of Applied Physics, Guru Jambheshwar University of Science and Technology, Hisar-125001, Haryana (India); Bhardwaj, S. [Department of Physics, Deenbandhu Chhotu Ram University of Science and Technology, Murthal, Sonepat-131093, Haryana (India); Sanjay [Department of Applied Science and Humanities, Rawal Institute of Engineering and Technology, Fridabad-121006, Haryana (India)

2014-04-24

247

Intense 1.6 ?m fluorescence of Nd3+ doped cadmium bismuth silicate glasses  

NASA Astrophysics Data System (ADS)

In this work, Judd-Ofelt analysis is applied to rare-earth (RE = Nd3+) doped cadmium bismuth silicate (20CdO?xSiO2?(79.5-x)Bi2O3?0.5Nd2O3 (CSBN)) glasses in order to evaluate their potential as well as both glass laser systems and optical materials. The phenomenological Judd-Ofelt parameters (?2, ?4, ?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 4F3/2?4I11/2 has high and varies 14.72×10-20 to 9.66×10-20 cm2 with Bi2O3 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 BiO6, SiO4 and non-bridging oxygen as local structure.

Pal, I.; Agarwal, A.; Sanghi, S.; Bhardwaj, S.; Sanjay

2014-04-01

248

Correlation of ion dynamics and structure of superionic tellurite glasses  

SciTech Connect

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.

Dutta, D.; Ghosh, A. [Department of Solid State Physics, Indian Association for the Cultivation of Science, Jadavpur, Kolkata-700 032 (India)

2008-01-28

249

Correlation of ion dynamics and structure of superionic tellurite glasses  

NASA Astrophysics Data System (ADS)

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.

Dutta, D.; Ghosh, A.

2008-01-01

250

Correlation of ion dynamics and structure of superionic tellurite glasses.  

PubMed

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. PMID:18247973

Dutta, D; Ghosh, A

2008-01-28

251

Use of CsCl to enhance the glass stability range of tellurite glasses for Er 3+ doped optical fiber drawing  

NASA Astrophysics Data System (ADS)

Tellurite glasses are important as a host of Er 3+ ions because of their great solubility and because they present broader gain bandwidths than Er 3+-doped silica, with promise to increase the bandwidth of communication systems. However, the small glass stability range (GSR) of tellurite glasses compromises the quality of the optical fibers. We show that the addition of CsCl to tellurite glasses can increase their GSR, making it easier to draw good quality optical fibers. CsCl acts as a network modifier in glass systems, weakening the network by forming Te-Cl bonds. We show that the thermal expansion coefficient mismatch is in the right direction for optical fiber fabrication purposes and that the Bi IIO 3 content can be used to control the refractive index of clad and core glasses. Single-mode and multi-mode Er 3+-doped optical fibers were produced by the rod-in-tube method using highly homogeneous TeO II-ZnO-Li IIO-Bi IIO 3-CsCl glasses. Far infrared spectra of the glass samples exhibit absorption bands of the Te-Cl bond.

Eyzaguirre, Carmen Rosa; Rodriguez, Eugenio; Chillcce, Enver Fernandez; Amaral Osório, Sérgio Paulo; Lenz Cesar, Carlos; Odone Mazali, Italo; Luiz Alves, Oswaldo; Carlos Barbosa, Luiz

2007-02-01

252

Synthesis and properties of ZnTe and Eu3+ ion co-doped glass nanocomposites  

NASA Astrophysics Data System (ADS)

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 (?cut-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-treated glass nanocomposites has been found to decrease with increase in heat-treatment duration (5.5-5.3 GPa). However, mechanical properties are found to be suitable for device applications.

Rahaman Molla, Atiar; Tarafder, Anal; Dey, Chirantan; Karmakar, Basudeb

2014-10-01

253

Optical studies on Eu{sup 3+} doped boro-tellurite glasses  

SciTech Connect

Eu{sup 3+} doped boro-tellurite glasses with the chemical composition (39-x)B{sub 2}O{sub 3}+30TeO{sub 2}+15MgO+15K{sub 2}O +xEu{sub 2}O{sub 3} (where x = 0.01, 0.1, 1, 2 and 3 wt%) have been prepared by following conventional melt quenching technique. Spectroscopic properties of the Eu{sup 3+} doped boro-tellurite glasses have been studied by recording the optical absorption and luminescence measurements. Through the optical absorption spectra, bonding parameters ({beta}-bar, {delta}) have been calculated to identify the ionic/covalent nature of the glasses. Judd-Ofelt (JO) analysis have been carried out using the luminescence spectra. The JO parameters ({Omega}{sub {lambda}}= 2, 4 and 6) were used to calculate the radiative properties for the {sup 5}D{sub 0}{yields}{sup 7}F{sub J} (J = 1, 2, 3 and 4) emission transitions of the Eu{sup 3+} ions. The change in optical properties with the variation of Eu{sup 3+} ion concentration have been studied and discussed with similar studies.

Maheshvaran, K.; Marimuthu, K. [Department of Physics, Gandhigram Rural Institute - Deemed University, Gandhigram - 624 302 (India)

2012-06-05

254

Time Evolution of Radiation-Induced Luminescence in Terbium-Doped Silicate Glass  

NASA Technical Reports Server (NTRS)

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.

West, Michael S.; Winfree, William P.

1996-01-01

255

Luminescence properties of Dy3+ doped different fluoro-phosphate glasses for solid state lighting applications  

NASA Astrophysics Data System (ADS)

Dy3+ doped different fluoro-phosphate glasses are prepared and they are characterized by X-ray diffraction (XRD), Scanning Electron Microscopy (SEM), Fourier Transform Infrared (FTIR), Raman, optical absorption, and photoluminescence (PL) techniques. The structural characterization is accomplished by XRD, FTIR and Raman spectroscopy. The morphological analysis was performed by SEM. The absorption spectra have been analyzed using Judd-Ofelt theory and the intensity parameters have been evaluated. These parameters are used to calculate radiative properties such as emission probabilities (AR), radiative lifetimes (?R) and integrated absorption cross-sections (?) for different Dy3+ transitions. The PL spectra exhibit bands in the blue, yellow and red regions. Furthermore, the dependence of luminescence properties such as stimulated emission cross-sections (?p) and branching ratios (?) on different metal cations in these glasses is studied. From decay curve analysis, the lifetimes of the excited state 4F9/2 have been measured. The calorimetric property is also studied based on Commission International del'Eclairage (CIE) standards for Dy3+ doped different fluoro-phosphate glasses and discussed.

Babu, S.; Reddy Prasad, V.; Rajesh, D.; Ratnakaram, Y. C.

2015-01-01

256

Fluorescence and thermal stress properties of Yb3+-doped alumino silicate glasses for ultra high peak power laser applications  

NASA Astrophysics Data System (ADS)

Various alumino silicate glasses (network modifier ions: Li+, Mg2+, Zn2+ and/or La3+) doped with 1? × ?1020 Yb3+?cm?3 (about 0.2?mol% Yb2O3) were prepared. The glasses were studied with respect to their thermo-mechanical and fluorescence properties. Huge differences are found for the coefficients of thermal expansion which determine the thermal shock resistance of the material and hence are required for ultra-high power laser applications. Here, zinc and magnesium alumino silicate glasses show the lowest values. The fluorescence lifetimes of the glasses increase with decreasing average atomic weight of the glass composition (685–1020?µs). All glasses show broad and smooth emission spectra with little variations due to compositional changes. Mixed lithium zinc or lithium magnesium alumino silicate glasses could be promising new laser materials especially with respect to ultra-high peak power systems or applications with high repetition rates.

Tiegel, Mirko; Herrmann, Andreas; Kuhn, Stefan; Rüssel, Christian; Körner, Jörg; Klöpfel, Diethard; Seifert, Reinhard; Hein, Joachim; Kaluza, Malte C.

2014-11-01

257

Absolute quantum cutting efficiency of Tb3+-Yb3+ co-doped glass  

NASA Astrophysics Data System (ADS)

The absolute quantum cutting efficiency of Tb3+-Yb3+ co-doped glass was quantitatively measured by an integrating sphere detection system, which is independent of the excitation power. As the Yb3+ concentration increases, the near infrared quantum efficiency exhibited an exponential growth with an upper limit of 13.5%, but the visible light efficiency was reduced rapidly. As a result, the total quantum efficiency monotonically decreases rather than increases as theory predicted. In fact, the absolute quantum efficiency was far less than the theoretical value due to the low radiative efficiency of Tb3+ (<61%) and significant cross-relaxation nonradiative loss between Yb3+ ions.

Duan, Qianqian; Qin, Feng; Zhao, Hua; Zhang, Zhiguo; Cao, Wenwu

2013-12-01

258

Spatially resolved measurement of high doses in microbeam radiation therapy using samarium doped fluorophosphate glasses  

SciTech Connect

The measurement of spatially resolved high doses in microbeam radiation therapy has always been a challenging task, where a combination of high dose response and high spatial resolution (microns) is required for synchrotron radiation peaked around 50 keV. The x-ray induced Sm{sup 3+}{yields} Sm{sup 2+} valence conversion in Sm{sup 3+} doped fluorophosphates glasses has been tested for use in x-ray dosimetry for microbeam radiation therapy. The conversion efficiency depends almost linearly on the dose of irradiation up to {approx}5 Gy and saturates at doses exceeding {approx}80 Gy. The conversion shows strong correlation with x-ray induced absorbance of the glass which is related to the formation of phosphorus-oxygen hole centers. When irradiated through a microslit collimator, a good spatial resolution and high ''peak-to-valley'' contrast have been observed by means of confocal photoluminescence microscopy.

Okada, Go; Morrell, Brian; Koughia, Cyril; Kasap, Safa [Department of Electrical and Computer Engineering, University of Saskatchewan, Saskatoon, SK S7N 5A9 (Canada); Edgar, Andy; Varoy, Chris [School of Chemical and Physical Sciences and MacDiarmid Institute, Victoria University of Wellington, Kelburn Parade (New Zealand); Belev, George; Wysokinski, Tomasz [Canadian Light Source Inc., University of Saskatchewan, Saskatoon, SK S7N 0X4 (Canada); Chapman, Dean [Department of Anatomy and Cell Biology, University of Saskatchewan, Saskatoon, SK S7N 5E5 (Canada)

2011-09-19

259

Resonant effects in nonlinear photon absorption during femtosecond laser ablation of Nd-doped silicate glass.  

PubMed

This study investigates the resonant effects in nonlinear photon absorption in femtosecond laser ablation of Nd-doped silicate glass (Nd:glass). During the femtosecond laser ablation process, the resonant ablation threshold fluence is decreased by up to 40% compared with that of ordinary ablation. However, it is found that the resonant effect is closely related with laser intensity, and lower laser intensities are required to achieve a significant enhancement. When the intensity is lower than 2.28×10(14) W/cm(2) at which multiphoton ionization dominates, resonant effect is enhanced by a factor of 1.4 to 4.4. When the intensity is higher than 2.28×10(14) W/cm(2), at which intensity tunnel ionization dominates, the resonant effect becomes weak and gradually fades away. It is shown that the resonant effect is still important for multiphoton ionization yet insignificant for tunnel ionization. PMID:23052083

Zhao, Yadong; Jiang, Lan; Fang, Juqiang; Chen, Qianghua; Li, Xiaowei; Lu, Yongfeng

2012-10-10

260

Spatially resolved measurement of high doses in microbeam radiation therapy using samarium doped fluorophosphate glasses  

NASA Astrophysics Data System (ADS)

The measurement of spatially resolved high doses in microbeam radiation therapy has always been a challenging task, where a combination of high dose response and high spatial resolution (microns) is required for synchrotron radiation peaked around 50 keV. The x-ray induced Sm3+ ? Sm2+ valence conversion in Sm3+ doped fluorophosphates glasses has been tested for use in x-ray dosimetry for microbeam radiation therapy. The conversion efficiency depends almost linearly on the dose of irradiation up to ˜5 Gy and saturates at doses exceeding ˜80 Gy. The conversion shows strong correlation with x-ray induced absorbance of the glass which is related to the formation of phosphorus-oxygen hole centers. When irradiated through a microslit collimator, a good spatial resolution and high "peak-to-valley" contrast have been observed by means of confocal photoluminescence microscopy.

Okada, Go; Morrell, Brian; Koughia, Cyril; Edgar, Andy; Varoy, Chris; Belev, George; Wysokinski, Tomasz; Chapman, Dean; Kasap, Safa

2011-09-01

261

Molecular orbital model of optical centers in bismuth-doped glasses.  

PubMed

Spectroscopic properties of optical fibers with a bismuth-doped silicate glass core are explained on the basis of molecular orbital theory and a solution of the Schrödinger equation, which takes into account the exchange, the spin-orbital, and the glass field potential interactions of s, p, and d electron shells of bismuth with s(sigma), p(sigma), and p(pi) orbits of oxygen atoms. The approach can explain the IR luminescence properties of other optical centers formed by other atoms with the same structure of electron shells as the bismuth atom. The model of transitions based on intramolecular charge transfer between molecular orbital and metallic states is proposed. PMID:19448817

Kustov, E F; Bulatov, L I; Dvoyrin, V V; Mashinsky, V M

2009-05-15

262

Analysis of thermal and structural properties of germanate glasses co-doped with Yb3+/Tb3+ ions  

NASA Astrophysics Data System (ADS)

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.

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

2014-10-01

263

Analysis of thermal and structural properties of germanate glasses co-doped with Yb(3+)/Tb(3+) ions.  

PubMed

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 Yb(3+)/Tb(3+)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 800cm(-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 621nm corresponding to (5)D4?(7)FJ (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. PMID:24928347

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

2014-10-15

264

Controlling the Spectral Characteristics of Bismuth Doped Silicate Glass Based on the Reducing Reaction of Al Powder  

NASA Astrophysics Data System (ADS)

Silicate glasses co-doped with Al metal powder and Bi2O3 are prepared. The effects of Al on spectral properties of samples are studied. It is found that the absorption intensity increases with increasing Al concentration in bismuth doped silicate glasses. The near-infrared (NIR) emission of the samples can be controlled by Al powder concentration no matter whether or not excited by 808 nm or 976 nm lasers. Furthermore, the influence of Al on formation of Bi-NIR active ions is discussed. The dependence relationship between the emission property of ~416 nm and Al concentration is a way to investigate the NIR emission origin of bismuth doped glass.

Wang, Yan-Shan; Jiang, Zuo-Wen; Peng, Jing-Gang; Li, Hai-Qing; Yang, Lu-Yun; Li, Jin-Yan; Dai, Neng-Li

2013-04-01

265

Structural, vibrational and dielectric studies of Sm3+-doped K-Mg-Al zincfluorophosphate glasses  

NASA Astrophysics Data System (ADS)

Trivalent samarium doped K-Mg-Al zincfluorophosphate glasses of composition (53-x/2)P2O5+15K2O+(14-x/2)MgO+10ZnF2+8Al2O3+xSm2O3 (where x=0.0, 0.1, 0.5 and 1.0 mol%) were prepared using the conventional melt-quenching technique and characterized for their structural, vibrational and dielectric properties. The amorphous nature, elemental analysis and thermal stability of the glasses were respectively studied by using X-ray diffraction, energy dispersive spectrum and differential scanning calorimetry analysis. Vibrational analysis of the structural groups in the glasses was carried out by both Raman and Fourier transform infrared spectra. The influence of Sm3+ ions on the variation of dielectric properties of the present glasses was investigated. It is evident that the tuning of dielectric properties could be made out by tailoring the concentration of Sm3+ ions. The power-law parameters and Cole-Cole parameters were estimated and their dependence on concentration of Sm3+ ions is discussed.

Thomas, Sunil; George, Rani; Rathaiah, M.; Venkatramu, V.; Rasool, Sk. Nayab; Unnikrishnan, N. V.

2013-12-01

266

Space-selective modification of Au-doped optical grade glass by the femtosecond laser beam  

NASA Astrophysics Data System (ADS)

Femtosecond laser-induced modification of Au-doped phosphate glass at different pulse repetition rates using an Yb femtosecond amplifier emitting pulses of up to 120 ?J energy at 1030 nm with adjustable repetition rate up to 100 kHz is presented. At the repetition rate as low as 1 kHz, only refractive index modification and formation of red color centers are observed. Increasing the average output laser power resulted in increase of color intensity, but this color could be easily erased by the heat treatment at 300?C for 20 min indicating athermal nature of these laser-induced effects. By contrast, at the repetition rate from 25 kHz to 100 kHz, cumulative heating effect was demonstrated and allowed to realize for the first time one-stage laser-induced growth of Au nanoparticles in the solid glass accompanied by the appearance of a thermally stable red color. Z-scan analysis of nonlinear properties of the studied glass samples is carried out. Details of Au nanoparticles growth and phosphate glass modification by the tightly focused femtosecond laser beam are discussed.

Lipatiev, Alexey S.; Lotarev, Sergey V.; Lipateva, Tatiana O.; Savinkov, Vitaliy I.; Shakhgildyan, Georgiy Y.; Kazansky, Peter G.; Sigaev, Vladimir N.

2015-01-01

267

Effect of ZnO on spectroscopic properties of Sm3+ doped zinc phosphate glasses  

NASA Astrophysics Data System (ADS)

Spectroscopic properties of Sm3+ containing zinc oxide based phosphate glasses in the chemical composition (50-x)P2O5+20Na2HPO4+9AlF3+xZnO+1Sm2O3 (where x=5, 10, 15, 20 and 25) have been studied. Raman, optical absorption, emission spectra and luminescence decay profiles were recorded and systematically analyzed. Using Judd-Ofelt theory, Judd-Ofelt intensity parameters ?? (?=2, 4 and 6), spontaneous radiative transition probabilities (Arad), radiative lifetimes (?R), branching ratios (?) were calculated and discussed. With 400 nm wavelength excitation, the emission spectra and decay lifetime of 4G52 level of Sm3+ doped zinc-phosphate glasses were studied. The branching ratios and emission cross-sections for the transition, 4G5/2?6H7/2 are found to be higher for x=25 mol% of zinc-phosphate glass matrix. The observed decay profiles were found to be exhibiting non-exponential behavior for all zinc-phosphate glasses, due to non-radiative energy transfer among the excited Sm3+ ions.

Seshadri, M.; Radha, M.; Rajesh, D.; Barbosa, L. C.; Cordeiro, C. M. B.; Ratnakaram, Y. C.

2015-02-01

268

Nano-silver enhanced luminescence of Eu3+-doped lead tellurite glass  

NASA Astrophysics Data System (ADS)

Eu3+-doped lead sodium tellurite glasses containing silver nanoparticles (NPs) were synthesized by melt-quenching technique and annealed for different time intervals at above the glass transition temperature. The glasses were characterized by UV-Vis-IR absorption, photoluminescence spectroscopy and transmission electron microscope imaging. Four absorption peaks of Eu3+ ion were observed due to transitions from ground state to different excited states in 400-600 nm region. The surface plasmon resonance (SPR) peak of silver NPs was probed at 632 nm. Five emission lines were recorded at 568, 587, 614, 650 and 704 nm which were intensified in the order of ˜1.9 times for heat-treated samples containing silver NPs. The average size of NPs was estimated to be ˜10 nm. Different mechanisms for interaction of light with metal and luminescent ions are discussed. Such enhancements are attributed to the strong local electric field induced by SPR of silver NPs as the major factor, and energy transfer from surface of silver NP to Eu3+ ion. The glasses show promising properties for optical applications.

Reza Dousti, M.; Sahar, M. R.; Rohani, M. S.; Samavati, Alireza; Mahraz, Zahra Ashur; Amjad, Raja J.; Awang, Asmahani; Arifin, R.

2014-05-01

269

Novel Eu{sup 3+}-doped lead telluroborate glasses for red laser source applications  

SciTech Connect

We report the absorption, luminescence and decay analysis of Eu{sup 3+}-doped lead telluroborate (PTBEu) glasses for different Eu{sup 3+} concentrations ranging from 0.1 to 2.0 mol%. Judd-Ofelt intensity parameters obtained from {sup 5}D{sub 0}{yields}{sup 7}F{sub J=0-6} emission transitions of Eu{sup 3+} were used to calculate the radiative transition probabilities, luminescence branching ratios and radiative decay times. The luminescence spectra and decay times were measured at 464 nm excitation. The optical band gap energies are also determined. The luminescence intensity ratio, color purity and emission cross-section values support that the PTBEu20 glass is a suitable candidate for red laser source applications. - Graphical abstract: Luminescence spectrum of the PTBEu20 glass with CIE coordinates. Highlights: > J-O parameters are obtained from the intensities of {sup 5}D{sub 0}{yields}{sup 7}F{sub J} transitions of Eu{sup 3+} ion. > The intensity ratio between {sup 5}D{sub 0}{yields}{sup 7}F{sub 2} and {sup 5}D{sub 0}{yields}{sup 7}F{sub 1} transitions gives the information about red color richness. > PTBEu20 glass is a suitable solid state material for red laser source applications.

Vijaya Kumar, M.V. [Department of Physics, Rayalaseema University, Kurnool 518002 (India); Jamalaiah, B.C., E-mail: bcjamal@gmail.com [Department of Physics, Sree Vidyanikethan Engineering College, Tirupati 517102 (India); Department of Physics, Changwon National University, Changwon 641-773 (Korea, Republic of); Rama Gopal, K.; Reddy, R.R. [Department of Physics, Sri Krishnadevaraya University, Anantapur 515055 (India)

2011-08-15

270

Fluorine-doping concentration and fictive temperature dependence of self-trapped holes in SiO{sub 2} glasses  

SciTech Connect

Fictive temperature (T{sub f}) and fluorine (F)-doping concentration dependences of self-trapped holes (STHs) in silica glasses created by UV irradiation at low temperatures have been studied by the electron-paramagnetic-resonance method. It was found that the yield of STH decreases with decreasing T{sub f} and increasing F-doping concentration. In combination with infrared spectra measurements, the correlation among T{sub f}, F-doping concentration, Si-O bond length, and Si-O-Si bond angle was elucidated. We conclude that the change in both T{sub f} and F doping can modify the network of SiO{sub 2} glass, leading to the suppression of the formation of STHs.

Wang, R.P.; Tai, N.; Saito, K.; Ikushima, A.J. [Research Center for Advanced Photon Technology, Toyota Technological Institute, 2-12-1 Hisakata, Tempaku, Nagoya 468-8511, Japan and Laser Physics Centre, Research School of Physical Science and Engineering, Australian National University, Canberra ACT 0200 (Australia); Research Center for Advanced Photon Technology, Toyota Technological Institute, 2-12-1 Hisakata, Tempaku, Nagoya 468-8511 (Japan)

2005-07-15

271

GeO2 influence on the formation of near-infrared emitting centers in Bi-doped multicomponent silicate glasses  

NASA Astrophysics Data System (ADS)

A meaningful increase in the number of NIR emission centers was experimentally observed in bismuth-doped multicomponent silicate glasses additionally doped with germanium dioxide. The emission and excitation spectra of the glass sets were monitored and compared with the spectra of radiative oxygen-deficient centers in vitreous silica and germania.

Denker, B. I.; Firstov, S. V.; Galagan, B. I.; Sverchkov, S. E.; Dianov, E. M.

2014-11-01

272

Thermal lens study of thermo-optical properties and concentration quenching of Er3+-doped lead pyrophosphate-based glasses  

NASA Astrophysics Data System (ADS)

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.

Santos, C. C.; Rocha, U.; Guedes, I.; Vermelho, M. V. D.; Boatner, L. A.; Jacinto, C.

2012-06-01

273

Thermal lens study of thermo-optical properties and concentration quenching of Er3+-doped lead pyrophosphate based glasses  

SciTech Connect

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.

Santos, C. C. [Universidade Federal do Ceara, Ceara, Brazil; Rocha, U. [Grupo de Fotônica e Fluidos Complexos, Instituto de Física, Brazil; Guedes, Ilde [Universidade Federal do Ceara, Ceara, Brazil; Vermelho, M. V. D. [Instituto de Fisica, Universidade Federal de Alagoas, Brazil; Boatner, Lynn A [ORNL; Jacinto, C. [Instituto de Fisica, Universidade Federal de Alagoas, Brazil

2012-01-01

274

Effect of Ga2O3 on the spectroscopic properties of erbium-doped boro-bismuth glasses.  

PubMed

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

Ling, Zhou; Ya-Xun, Zhou; Shi-Xun, Dai; Tie-Feng, Xu; Qiu-Hua, Nie; Xiang, Shen

2007-11-01

275

Synthesis and characterization of Dy3+ doped zinc-lead-phosphate glass  

NASA Astrophysics Data System (ADS)

Dysprosium doped-zinc-lead-phosphate glasses having composition (60 - x) P2O5-20PbO-20ZnO-xDy2O3 where x = 0, 0.5, 1.0, and 3.0 mol% were prepared by melt quenching technique. Archimedes method was used to measure their densities that are used to calculate the molar volumes. The values of densities lie in the range 3.58-3.74 gm/cm3 whereas those of molar volume lie in the range of 40.80-41.10 cm-3. The UV-VIS-NIR absorption spectroscopy in the wavelength range 300-1400 nm was carried out. Absorption spectra consist of eight absorption peaks corresponding to the transitions from the 6H15/2 ground state to various excited energy levels. Judd-Ofelt analysis of Dy3+ doped zinc-lead-phosphate is also accomplished. The energy band gap measured from the optical absorbance found to be in the range of 4.50-4.68 eV and 4.21-4.50 eV for direct and indirect transitions respectively. The IR spectra reveal the significant structural changes inside the glass induced by modifiers lead oxide and zinc oxide, explained in terms of the distortion of PO4 tetrahedra and network depolymerization process. Differential thermal analysis confirms the glass stability in the presence of Dy3+ ions. In addition, photoluminescence spectra shows three prominent emission bands centered at 475, 586 and 675 nm corresponds to the 4F9/2 ? 6HJ (J = 11/2, 13/2, 15/2) transitions respectively and the intensity of all the bands are enhanced as the concentration of Dy3+ ions increased.

Amjad, Raja J.; Sahar, M. R.; Ghoshal, S. K.; Dousti, M. R.; Arifin, R.

2013-03-01

276

Differentiation of human mesenchymal stem cells on niobium-doped fluorapatite glass-ceramics  

PubMed Central

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

Kushwaha, Meenakshi; Pan, Xueliang; Holloway, Julie A.; Denry, Isabelle L.

2011-01-01

277

The Effect of Remelting on the Physical Properties of Borotellurite Glass Doped with Manganese  

PubMed Central

A systematic set of borotellurite glasses doped with manganese (1–x) [(B2O3)0.3(TeO2)0.7]-xMnO, with x = 0.1, 0.2, 0.3 and 0.4 mol%, were successfully synthesized by using a conventional melt and quench-casting technique. In this study, the remelting effect of the glass samples on their microstructure was investigated through density measurement and FT-IR spectra and evaluated by XRD techniques. Initial experimental results from XRD evaluation show that there are two distinct phases of glassy and crystallite microstructure due to the existence of peaks in the sample. The different physical behaviors of the studied glasses were closely related to the concentration of manganese in each phase. FTIR spectra revealed that the addition of manganese oxide contributes the transformation of TeO4 trigonal bipyramids with bridging oxygen (BO) to TeO3 trigonal pyramids with non-bridging oxygen (NBO). PMID:23296276

Hashim, Syed Putra Hashim Syed; Sidek, Haji Abdul Aziz; Halimah, Mohamed Kamari; Matori, Khamirul Amin; Yusof, Wan Mohamad Daud Wan; Zaid, Mohd Hafiz Mohd

2013-01-01

278

XRD and IR Studies of Yb{sup 3+} Doped Tellurite Glass  

SciTech Connect

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.

Sahar, M. R.; Isa, H. Noor [Advanced Optical Material Reseach Group, Department of Physics, Universiti Teknologi Malaysia, 81310 Skudai Johor Bahru (Malaysia)

2011-03-30

279

Application of Cu2O-doped phosphate glasses for bandpass filter  

NASA Astrophysics Data System (ADS)

Phosphate glasses doped with copper ions having general composition 42P2O5-39ZnO-(18-x) Na2O-1CaO-xCu2O [x=2, 4, 6, 8, 10 mol%] were prepared using a conventional melt-quench technique. Physical and chemical properties of the glasses were investigated using X-ray diffraction technique and UV-visible optical absorption. The density was measured by Archimedes' method, and molar volume (VM) was calculated. It is found that density and molar volume show opposite trend by increasing Cu2O content. Absorbance and transmittance at the normal incidence are measured by a spectrophotometer in the spectral range of 190-1100 nm. Analyses of the obtained results were considered in the frame of current theories. Absorption data were used for absorption coefficient, the optical band gap (Eopt), the cutoff in UV and IR bands to the bandpass filter, which confirmed the optical properties of this type of filter. Eopt values for different glass samples are found to decrease with increasing Cu2O content.

Elhaes, H.; Attallah, M.; Elbashar, Y.; El-Okr, M.; Ibrahim, M.

2014-09-01

280

Comparison of ion exchange and cw CO 2 laser treatment of Nd-doped phosphate laser glass  

NASA Astrophysics Data System (ADS)

We investigate the relation of ion-exchange treatment and laser conditioning of a glass surface. The surface of Nd-doped phosphate laser glass was preirradiated with a cw CO 2 laser and strengthened by the ion-exchange treatment. It is shown that residual compressive stress occurs on the surface as peak-to-valley roughness and the appearance of microcracks decreases. Damage threshold of the glass surface increases by a factor of 1.7 3. The mechanism of laser conditioning is consistent with that of the ion-exchange treatment.

Gong, Hui; Li, Chengfu

1997-07-01

281

Mg- and/or Sr-doped tricalcium phosphate/bioactive glass composites: synthesis, microstructure and biological responsiveness.  

PubMed

Presently, there is an increasing interest towards the composites of calcium phosphates, especially ?-tricalcium phosphate (TCP), and bioactive glasses. In the present contribution, the recently developed BG_Ca/Mix glass has been used because its low tendency to crystallize allows to sinter the composites at relatively low temperature (i.e. 850°C), thus minimizing the glass devitrification and the interaction with TCP. A further improvement is the introduction of lab-produced TCP powders doped with specific ions instead of non-doped commercial powders, since the biological properties of materials for bone replacement can be modulated by doping them with certain metallic ions, such as Mg and Sr. Therefore, novel binary composites have been produced by sintering the BG_Ca/Mix glass with the addition of pure, Mg-substituted, Sr-substituted or Mg/Sr bisubstituted TCP powders. After an accurate characterization of the starting TCP powders and of the obtained samples, the composites have been used as three-dimensional supports for the culture of mouse calvaria-derived pre-osteoblastic cells. The samples supported cell adhesion and proliferation and induced promising mechanisms of differentiation towards an osteoblastic phenotype. In particular, the Mg/Sr bi-doped samples seemed to better promote the differentiation process thus suggesting a combined stimulatory effect of Mg(2+) and Sr(2+) ions. PMID:25063124

Bellucci, Devis; Sola, Antonella; Cacciotti, Ilaria; Bartoli, Cristina; Gazzarri, Matteo; Bianco, Alessandra; Chiellini, Federica; Cannillo, Valeria

2014-09-01

282

Development of large scale production of Nd-doped phosphate glasses for megajoule-scale laser systems  

SciTech Connect

Nd-doped phosphate glasses are the preferred gain medium for high-peak-power lasers used for Inertial Confinement Fusion research because they have excellent energy storage and extraction characteristics. In addition, these glasses can be manufactured defect-free in large sizes and at relatively low cost. To meet the requirements of the future mega-joule size lasers, advanced laser glass manufacturing methods are being developed that would enable laser glass to be continuously produced at the rate of several thousand large (790 x 440 x 44 mm{sup 3}) plates of glass per year. This represents more than a 10 to 100-fold improvement in the scale of the present manufacturing technology.

Ficini, G. [Centre d`Etudes de Limeil-Valenton, Villeneuve, St. Georges (France); Campbell, J.H. [Lawrence Livermore National Lab., CA (United States)

1996-05-01

283

A parametric study of Er 3+-ions doped Phospho-tellurite glass thin films by pulsed laser deposition  

NASA Astrophysics Data System (ADS)

Phospho-tellurite glass thin films have been deposited on silica substrates using an ArF laser ( ? = 193 nm, ? = 20 ns) at a laser fluence of 3.2 J/cm 2 and for various oxygen pressures, substrate temperatures and target-to-substrate distances. The measured propagation losses of the phospho-tellurite glass thin films are in the range of 0.13-0.75 dB/cm, whilst the refractive indices of the glass thin films were in the range of 1.623-1.649 which is very close to that of the target glass, showing nearly stoichiometric transfer of the material from target to substrate. The results show significant promise for integrated active optical device applications using pulsed laser deposition (PLD) of this erbium doped phospho-tellurite glass material.

Irannejad, M.; Jose, G.; Jha, A.; Steenson, D. P.

2010-12-01

284

Blue emission from Eu{sup 2+}-doped high silica glass by near-infrared femtosecond laser irradiation  

SciTech Connect

Eu{sup 2+}-doped high silica glass (HSG) is fabricated by sintering porous glass which is impregnated with europium ions. Eu{sup 2+}-doped HSG is revealed to yield intense blue emission excited by ultraviolet (UV) light and near-infrared femtosecond laser. The emission profile obtained by UV excitation can be well traced by near-infrared femtosecond laser. The upconversion emission excited by 800 nm femtosecond laser is considered to be related to a two-photon absorption process from the relationship between the integrated intensity and the pump power. A tentative scheme of upconverted blue emission from Eu{sup 2+}-doped HSG was also proposed. The HSG materials presented herein are expected to find applications in high density optical storage and three-dimensional color displays.

Qiao Yanbo; Chen Danping; Ren Jinjun; Wu Botao [Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Shanghai 201800 (China); Graduate School of the Chinese Academy of Sciences, Beijing 100039 (China); Qiu Jianrong [College of Materials Science and Chemical Engineering, Zhejiang University, Hangzhou 310027 (China); Akai, Tomoko [National Institute of Advanced Industrial Science and Technology, Osaka 563-8577 (Japan)

2008-01-15

285

Radiative parameters of Nd3+-doped titanium and tungsten modified tellurite glasses for 1.06 ?m laser materials  

NASA Astrophysics Data System (ADS)

Different glass matrices doped with Nd3+ have been prepared by the conventional melt quenching method with the molar compositions of (89-x)TeO2-10TiO2-1Nd2O3-xWO3 (x=0, 10 and 20 mol%). The XRD, FTIR, absorption spectra, photoluminescence (PL) spectra and luminescence decay curves of glass samples were measured at room temperature and investigated, respectively. The XRD pattern confirms the amorphous nature of the prepared glasses. The free OH- content in the 1.0 mol% Nd2O3-doped glass samples has been estimated from their measured Infrared transmittance spectra. Judd-Ofelt (J-O) intensity parameters were derived from the absorption spectrum and used in turn to estimate radiative properties such as radiative transition probabilities (AT), radiative lifetimes (?r) and branching ratios (?JJ?) for 4F3/2?4I9/2, 11/2, 13/2 transitions. From the emission spectra, peak wavelength, effective bandwidth (??eff) and stimulated emission cross-section (?emis) were calculated for the 4F3/2?4I11/2 transition. The values of the stimulated emission cross-section obtained in the present Nd3+-doped tellurite glasses are on the higher side than the values of the reported as well as commercial. The luminescence decay curves for the 4F3/2?4I11/2 transition have been measured to evaluate the quantum efficiency (?). The results show a significant increase of the quantum efficiency (?) with the increases of WO3 concentration. Notably, it is found that the quantum efficiency in the TTNW20 glass is much longer than that in most other glasses which indicates that this glass system could be considered as a good candidate for near-infrared lasers at 1.06 ?m.

Fares, Hssen; Jlassi, Ifa; Hraiech, S.; Elhouichet, Habib; Férid, Mokhtar

2014-11-01

286

Fabrication and annealing optimization of oxygen-implanted Yb3+-doped phosphate glass planar waveguides  

NASA Astrophysics Data System (ADS)

Optical planar waveguides in Yb3+-doped phosphate glasses are fabricated by (5.0+6.0) MeV O3+ ion implantation at fluences of (4.0+8.0)×1014 ions/cm2. The annealing treatment is carried out to optimize waveguide performances. The prism-coupling and end-face coupling methods are used to measure the dark-mode spectra and near-field intensity distributions before and after annealing at 350 °C for 60 min, respectively. The refractive index profile of the planar waveguide is obtained based on the reflectivity calculation method. The micro-Raman spectrum of the waveguide is in agreement with that of the bulk, exhibiting possible applications for integrated active photonic devices.

Liu, Chun-Xiao; Xu, Jun; Li, Wei-Nan; Xu, Xiao-Li; Guo, Hai-Tao; Wei, Wei; Wu, Gen-Gen; Hu, Yue; Peng, Bo

2014-11-01

287

Pr{sup 3+}-doped fluoro-oxide lithium glass as scintillator for nuclear fusion diagnostics  

SciTech Connect

Experimental results are presented on the neutron scintillating properties of a custom-designed Pr3+(praseodymium)-doped lithium (Li) glass. Luminescence was observed at 278 nm wavelength, originating from the 5d-4f transition. Time-resolved measurements yielded about 20 ns decay times for ultraviolet and x-ray excitation while much faster decay times of about 6 ns were observed for alpha particle and neutron excitation. Actual time-of-flight data in laser fusion experiments at the GEKKO XII facility of the Institute of Laser Engineering, Osaka University reveal that it can clearly discriminate fusion neutrons from the much stronger x-rays signals. This material can promise improved accuracy in future scattered neutron diagnostics.

Arikawa, Yasunobu; Yamanoi, Kohei; Nakazato, Tomoharu; Estacio, Elmer Surat; Shimizu, Toshihiko; Sarukura, Nobuhiko; Nakai, Mitsuo; Norimatsu, Takayoshi; Azechi, Hiroshi [Institute of Laser Engineering, Osaka University, 2-6 Yamadaoka, Suita, Osaka 565-0871 (Japan); Murata, Takahiro [Department of Chemistry, School of Science, Tokai University, Kawayou, Minamiaso, Aso, Kumamoto 869-1404 (Japan); Fujino, Shigeru [Department of Materials Process Engineering, Graduate School of Engineering, Kyushu University, 744 Nishikyo Motooka, Fukuoka 819-0395 (Japan); Yoshida, Hideki [Ceramic Research Center of Nagasaki, Hiekoba, Hasami, Higashisonogi, Nagasaki 859-3726 (Japan); Kamada, Kei; Usuki, Yoshiyuki [Furukawa Co., Ltd., Kannondai, Tsukuba, Ibaraki 1-25-13 (Japan); Suyama, Toshihisa [Tokuyama Corporation Shibuya, 3-3-1, Shibuya, Tokyo 150-8383 (Japan); Yoshikawa, Akira [Institute of Multidisciplinary Research for Advanced Materials, Tohoku University, 2-1-1 Katahira, Aoyou, Sendai, Miyagi 980-8577 (Japan); Sato, Nakahiro; Kan, Hirofumi [Central Research Laboratory, Hamamatsu Photonics K. K., 5000 Hiraguchi, Hamakitaku, Hamamatsu, Shizuoka 434-8601 (Japan)

2009-11-15

288

Optical properties of phosphate glasses co-doped with Yb3+ and silver nanoparticles  

NASA Astrophysics Data System (ADS)

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.

A. Vallejo H., M.; A. Martinez G., M.; V. Kiryanov, A.; L. Lucio M., J.

2014-12-01

289

Synthesis of Aligned Copper Oxide Nanowires on Fluorine-Doped Tin Oxide Glass Substrate  

NASA Astrophysics Data System (ADS)

In this paper, the synthesis and characterization of uniform and dense CuO nanowires on fluorine-doped tin oxide (FTO) glass substrate are reported. The procedure simply involved the vapor-solid thermal oxidation growth process of CuO nanowires on FTO surface in the air flow. The sample was annealed in air within the temperature range 300-600°C for 1 h. The morphology and density of the CuO nanowires could be controlled by annealing temperature. The SEM image analysis indicates that the nanowires feature uniform size with aligned structures. The high-resolution transmission electron microscopy (HRTEM) result of individual CuO nanowires shows that the nanowires were single-crystalline, and the selected area diffraction pattern (SEAD) of the same sample shows that the nanowires grow along the (110) direction. The XRD analysis shows that CuO was the only product when the sample annealed at the temperature higher than 500°C.

Li, Xuyang; Kishi, Naoki; Soga, Tetsuo

2013-12-01

290

Investigations on luminescence behavior of Er3+/Yb3+ co-doped boro-tellurite glasses  

NASA Astrophysics Data System (ADS)

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 (?Ep), experimental and calculated branching ratios (?R) and radiative lifetime (?cal) 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.

Maheshvaran, K.; Arunkumar, S.; Venkata Krishnaiah, K.; Marimuthu, K.

2015-01-01

291

Gamma-ray irradiation resistance of silver doped GeS2-Ga2S3-AgI chalcohalide glasses  

NASA Astrophysics Data System (ADS)

In the present work, series of silver doped Ge-Ga-S-AgI chalcohalide glasses have been prepared and their optical transmission spectra are compared before and after ?-ray irradiation at different doses. The differential transmission spectra of the irradiated samples with and without Ag doping have been compared to characterize the ?-ray irradiation induced red-shift of electronic absorption and formation of color centers. Ag doping plays an important role in increasing ?-ray irradiation resistance of the chalcohalide glasses due to its specific effect on the valence band and the network structure of glasses.

Shen, W.; Baccaro, S.; Cemmi, A.; Ren, J.; Zhang, Z.; Zhou, Y.; Yang, Y.; Chen, G.

2014-06-01

292

Gamma-Ray Irradiation Resistance of Silver Doped GeS2-Ga2S3-AgI Chalcohalide Glasses  

NASA Astrophysics Data System (ADS)

In the present work, series of silver doped Ge-Ga-S-AgI chalcohalide glasses have been prepared and their optical transmission spectra are compared before and after ?-ray irradiation at different doses. The differential transmission spectra of the irradiated samples with and without Ag doping have been compared to characterize the ?-ray irradiation induced red-shift of electronic absorption and formation of color centers. Ag doping plays an important role in increasing ?-ray irradiation resistance of the chalcohalide glasses due to its specific effect on the valence band and the network structure of glasses.

Zhou, Y.; Shen, W.; Zhang, Z.; Yang, Y.; Chen, G.; Baccaro, S.; Cemmi, A.

2014-06-01

293

Thin transparent W-doped indium-zinc oxide (WIZO) layer on glass.  

PubMed

Annealing effect on structural and electrical properties of W-doped IZO (WIZO) films for thin film transistors (TFT) was studied under different process conditions. Thin WIZO films were deposited on glass substrates by RF magnetron co-sputtering technique using indium zinc oxide (10 wt.% ZnO-doped In2O3) and WO3 targets in room temperature. The post annealing temperature was executed from 200 degrees C to 500 degrees C under various O2/Ar ratios. We could not find any big difference from the surface observation of as grown films while it was found that the carrier density and sheet resistance of WIZO films were controlled by O2/Ar ratio and post annealing temperature. Furthermore, the crystallinity of WIZO film was changed as annealing temperature increased, resulting in amorphous structure at the annealing temperature of 200 degrees C, while clear In2O3 peak was observed for the annealed over 300 degrees C. The transmittance of as-grown films over 89% in visible range was obtained. As an active channel layer for TFT, it was found that the variation of resistivity, carrier density and mobility concentration of WIZO film decreased by annealing process. PMID:22966618

Lee, Young-Jun; Lim, Byung-Wook; Kim, Joo-Hyung; Kim, Tae-Won; Oh, Byeong-Yun; Heo, Gi-Seok; Kim, Kwang-Young

2012-07-01

294

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

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.

Huang Yanlin [School of Material Engineering, Soochow University, 178 GanJiang East Road, Suzhou 215021 (China); Jiang, Chuanfang; Jang, Kiwan; Lee, Ho Sueb; Cho, Eunjin; Jayasimhadri, M. [Department of Physics, Changwon National University, Changwon 641-773 (Korea, Republic of); Yi, Soung-Soo [Department of Photonics, Silla University, Busan 617-736 (Korea, Republic of)

2008-06-01

295

Charge carrier transport in molecularly doped polycarbonate as a test case for the dipolar glass model  

NASA Astrophysics Data System (ADS)

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.

Novikov, S. V.; Tyutnev, A. P.

2013-03-01

296

Charge carrier transport in molecularly doped polycarbonate as a test case for the dipolar glass model.  

PubMed

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. PMID:23514478

Novikov, S V; Tyutnev, A P

2013-03-14

297

Glass beads and Ge-doped optical fibres as thermoluminescence dosimeters for small field photon dosimetry  

NASA Astrophysics Data System (ADS)

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.

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

298

Glass beads and Ge-doped optical fibres as thermoluminescence dosimeters for small field photon dosimetry.  

PubMed

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. PMID:25350105

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

299

Spectroscopic and dielectric investigations of tungsten ions doped zinc bismuth phosphate glass-ceramics  

NASA Astrophysics Data System (ADS)

Pure and tungsten oxide doped ZnF2sbnd Bi2O3sbnd P2O5 glass-ceramics are prepared by the melt quenching and heat treatment techniques. These samples are characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), electron dispersive spectroscopy (EDS) and differential thermal analysis (DTA) techniques. The X-ray diffraction and the scanning electron microscopic studies have revealed the presence of BiPO4, ?-Zn3(PO4)2, ?-Zn(PO3)2, Zn3(PO4)2, WOF4, WOPO4, ?-Bi2WO6, Bi2W2O9, microcrystalline phases in these samples. FTIR and Raman studies exhibit bands due WO4 and WO6 units along with conventional phosphate groups. The optical absorption and electron spin resonance (ESR) spectra of present glass-ceramics indicate the co-existence of both W5+ and W6+ ions. The analysis of dielectric properties (dielectric constant, loss tan ?, a.c. conductivity) over a range of frequency and temperature suggests a gradual increase in semi conducting character with increase in the concentration of WO3. The studies on dielectric breakdown strength indicated the lowest insulating strength for 5.0 mol% of WO3 in the present samples.

Srinivasa Rao, P.; Bala Murali Krishna, S.; Yusub, S.; Ramesh Babu, P.; Tirupataiah, Ch.; Krishna Rao, D.

2013-03-01

300

Microstructure and optical properties of CdI{sub 2} doped silver vanadate glass-nanocomposites  

SciTech Connect

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 (?-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 ?-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 ?-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 ?-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.

Kabi, S. [Department of Solid State Physics, Indian Association for the Cultivation of Science, Jadavpur, Kolkata 700032 (India)] [Department of Solid State Physics, Indian Association for the Cultivation of Science, Jadavpur, Kolkata 700032 (India); Ghosh, A., E-mail: sspag@iacs.res.in [Department of Solid State Physics, Indian Association for the Cultivation of Science, Jadavpur, Kolkata 700032 (India)

2012-11-15

301

Energy transfer and energy level decay processes in Tm3+-doped tellurite glass  

NASA Astrophysics Data System (ADS)

The primary excited state decay and energy transfer processes in singly Tm3+-doped TeO2:ZnO:Bi2O3:GeO2 (TZBG) glass relating to the 3F4 ? 3H6 ˜1.85 ?m laser transition have been investigated in detail using time-resolved fluorescence spectroscopy. Selective laser excitation of the 3H4 manifold at 794 nm, the 3H5 manifold at 1220 nm, and 3F4 manifold at 1760 nm has established that the 3H5 manifold is entirely quenched by multiphonon relaxation in tellurite glass. The luminescence from the 3H4 manifold with an emission peak at 1465 nm suffers strong suppression due to cross relaxation that populates the 3F4 level with a near quadratic dependence on the Tm3+ concentration. The 3F4 lifetime becomes longer as the Tm3+ concentration increases due to energy migration and decreases to 2.92 ms when [Tm3+] = 4 mol. % as a result of quasi-resonant energy transfer to free OH- radicals present in the glass at concentrations between 1 × 1018 cm-3 and 2 × 1018 cm-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-1. The spectroscopic parameters, the cross relaxation and Tm3+(3F4) ? OH- energy transfer rates were used in a numerical model for laser transitions emitting at 2335 nm and 1865 nm.

Gomes, Laércio; Lousteau, Joris; Milanese, Daniel; Scarpignato, Gerardo C.; Jackson, Stuart D.

2012-03-01

302

Effect of silver nanoparticles incorporated with samarium-doped magnesium tellurite glasses  

NASA Astrophysics Data System (ADS)

Silver nanoparticles (Ag NPs) are incorporated in samarium doped tellurite glass of a composition (89-x)TeO2-10MgO-1Sm2O3-xAgCl, where 0.0?x?0.6 mol%, by a melt quenching technique. It is found that all the glasses are amorphous in nature, and the existence of Ag NPs with an average size of 16.94 nm is confirmed by Transmission Electron Microscopy. Meanwhile, their physical properties such as glass density, molar volume and ionic packing density are computed utilizing the normal method. The density and ionic packing density are observed to decrease with increasing Ag NPs, but increase when the Ag NPs are beyond 0.2 mol%. On the other hand, the molar volume behaves exactly opposite to the increase in Ag NPs content. It decreases when the Ag NPs content value is more than 0.2 mol%. The optical energy band gap and Urbach energy are evaluated from the absorption spectra in the range of 200-900 nm at room temperature. It is also observed that the direct and indirect optical energy band gaps reduce with Ag NPs content, but enhance when the Ag NPs are beyond 0.2 mol%. Meanwhile, the Urbach energy is found to increase as the Ag NPs content is increased but decreases when Ag NPs is 0.2 mol%. The refractive index is deduced from indirect optical energy band gap. Meanwhile, molar refraction and electronic polarizability have been calculated from the Lorentz-Lorentz relation. Refractive index and electronic polarizability are also observed to raise with Ag NPs content, but drop off when Ag NPs content is more than 0.2 mol%. In this paper, all properties are discussed with respect to the Ag NPs concentration.

Yusoff, N. M.; Sahar, M. R.

2015-01-01

303

Investigation of concentration quenching and 1.3 microm emission in Nd(3+)-doped bismuth glasses.  

PubMed

Nd(2)O(3)-doped 70Bi(2)O(3)-20B(2)O(3)-10SiO(2)-xNd(2)O(3) (x=0.1, 0.3, 0.5, 0.7, 1.0, 1.5 mol%) bismuth glasses were prepared by the conventional melt-quenching method, and the Nd(3+):(4)F(3/2)-->(4)I(13/2) fluorescence properties had been studied for different Nd(3+) concentrations. The Judd-Ofelt analysis for Nd(3+) ions in bismuth boron silicate glasses was also performed on the base of absorption spectrum. The transition probabilities, excited state lifetimes, the fluorescence branching ratios, quantum efficiency and the stimulated emission cross-sections of (4)F(3/2)-->(4)I(13/2) transition were calculated and discussed. Based on the electric dipole-dipole interaction theory, the interaction parameters: C(DD), for the energy migration rate (4)F(3/2), (4)I(9/2)-->(4)F(3/2), (4)I(9/2) and C(DA), for cross-relaxation rate (4)F(3/2), (4)I(9/2)-->(4)I(15/2), (4)I(15/2), and/or (4)F(3/2), (4)I(9/2)-->(4)I(13/2), (4)I(15/2) in bismuth boron silicate glasses were about 18.4 x 10(-40)cm(6)/s and 3.4 x 10(-40)cm(6)/s, respectively. PMID:17827056

Nie, Qiuhua; Li, Xujie; Dai, Shixun; Xu, Tiefeng; Jin, Zhenjuan; Zhang, Xianghua

2008-08-01

304

Magnetocaloric effect in heavy rare-earth elements doped Fe-based bulk metallic glasses with tunable Curie temperature  

NASA Astrophysics Data System (ADS)

The effects of heavy rare earth (RE) additions on the Curie temperature (TC) 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 TC in a large temperature range of 120 K without significantly decreasing the magnetic entropy change (?SM) and refrigerant capacity (RC) of the alloys. The observed values of ?SM and RC of these alloys compare favorably with those of recently reported Fe-based metallic glasses with enhanced RC compared to Gd5Ge1.9Si2Fe0.1. The tunable TC 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.

Li, Jiawei; Huo, Juntao; Law, Jiayan; Chang, Chuntao; Du, Juan; Man, Qikui; Wang, Xinmin; Li, Run-Wei

2014-08-01

305

Effect of absorption recovery in bismuth-doped silica glass at 1450 nm on soliton grouping in fiber laser.  

PubMed

Saturable absorption in bismuth-doped glasses was found to have a noticeable influence on soliton interaction and group formation. This phenomenon, observed in 1450 nm mode-locked bismuth-doped fiber laser, shows the distinct feature of the multiple pulse regime, which appears as a stationary pulse group whose length can be spread over the whole cavity length by variation of the pump power and polarization. Pulse positioning within the ensemble depends on the saturation fluence and the relatively fast recovery dynamics of bismuth fiber. PMID:25391808

Gumenyuk, R; Melkumov, M A; Khopin, V F; Dianov, E M; Okhotnikov, O G

2014-01-01

306

Effect of absorption recovery in bismuth-doped silica glass at 1450 nm on soliton grouping in fiber laser  

NASA Astrophysics Data System (ADS)

Saturable absorption in bismuth-doped glasses was found to have a noticeable influence on soliton interaction and group formation. This phenomenon, observed in 1450 nm mode-locked bismuth-doped fiber laser, shows the distinct feature of the multiple pulse regime, which appears as a stationary pulse group whose length can be spread over the whole cavity length by variation of the pump power and polarization. Pulse positioning within the ensemble depends on the saturation fluence and the relatively fast recovery dynamics of bismuth fiber.

Gumenyuk, R.; Melkumov, M. A.; Khopin, V. F.; Dianov, E. M.; Okhotnikov, O. G.

2014-11-01

307

Laser-induced radial birefringence and spin-to-orbital optical angular momentum conversion in silver-doped glasses  

E-print Network

Samples of Ag$^+$/Na$^{+}$ 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.

Amjad, Jafar Mostafavi; Slussarenko, Sergei; Karimi, Ebrahim; Marrucci, Lorenzo; Santamato, Enrico; 10.1063/1.3610474

2012-01-01

308

Controllable precipitation and dissolution of silver nanoparticles in ultrafast laser pulses irradiated Ag+-doped phosphate glass.  

PubMed

We report a controllable process of recipitation and dissolution of silver nanoparticles in ultrashort laser pulses irradiated Ag+-doped phosphate glass. Absorption spectra, transmission electron microscopy and refractive index measurement revealed that metallic silver nanoparticles were precipitated in the glass sample after irradiation by an 800-nm femtosecond laser and subsequent annealing at 300 degrees C, and dissolved after further annealing at 450 degrees C. We discuss a mechanism that combines the formation and decoloration of color centers, precipitation and dissolution of silver nanoparticles. PMID:19483943

Zhao, Quan-Zhong; Qiu, Jian-Rong; Jiang, Xiong-Wei; Zhao, Chong-Jun; Zhu, Cong-Shan

2004-08-23

309

Planar waveguides formed in a new chemically stable Er(3+)/Yb(3+) co-doped phosphate glass  

NASA Astrophysics Data System (ADS)

A new Er(3+)/Yb(3+) co-doped phosphate glass has been prepared, which exhibits good chemical durability and spectralproperties. Planar graded index waveguides have been fabricated in the glass by (Ag+)-Na(+) ion exchange in a mixed melt of silver nitrate and potassium nitrate. Ion exchange is carried out by varying the process parameters such as temperature, diffusion time, and molten salt compositions. The diffusion parameters, diffusion coefficients, and activation energy are determined by the guidelines of fabricated waveguides, which are determined by the input prism coupling technique.

Zhao, Shilong; Chen, Baoyu; Hu, Junjiang; Hu, Lili

2005-02-01

310

Controllable precipitation and dissolution of silver nanoparticles in ultrafast laser pulses irradiated Ag+-doped phosphate glass  

NASA Astrophysics Data System (ADS)

We report a controllable process of recipitation and dissolution of silver nanoparticles in ultrashort laser pulses irradiated Ag+-doped phosphate glass. Absorption spectra, transmission electron microscopy and refractive index measurement revealed that metallic silver nanoparticles were precipitated in the glass sample after irradiation by an 800-nm femtosecond laser and subsequent annealing at 300°C, and dissolved after further annealing at 450°C. We discuss a mechanism that combines the formation and decoloration of color centers, precipitation and dissolution of silver nanoparticles

Zhao, Quan-Zhong; Qiu, Jian-Rong; Jiang, Xiong-Wei; Zhao, Chong-Jun; Zhu, Cong-Shan

2004-08-01

311

Effect of Yb3+ concentration on the broadband emission intensity and peak wavelength shift in Yb/Bi ions co-doped silica-based glasses.  

PubMed

The effect of Yb(3+) concentration on the broadband emission intensity and peak wavelength shift in Yb/Bi ions co-doped silicate glasses is investigated. The optimal Bi(2)O(3) concentration range is about 2.0-2.5 mol% in 65SiO(2)-10Al(2)O(3)-25CaO matrix (SAC glasses). For Yb/Bi codoped SAC glasses, the maximum emission intensity excited by 980 nm LD is ~30 times and 1.5 times higher than that of single Bi-doped SAC glasses excited by 980 nm and 808 nm LD, respectively, the peak emission shows obvious red-shift from 1185 nm to 1235 nm band with the Yb(2)O(3) concentration change from 0 to 3.0 mol%. For the same Yb(2)O(3) concentration in SAC glasses, the measured fluorescence lifetime near 1020 nm of single Yb(3+)-doped glasses is longer than that of Yb/Bi codoping glasses, which implyes the efficient energy transfer from Yb(3+) to Bi(n+) in SAC glasses. The results indicate Yb(2)O(3) can be induced into the bismuth-doped silicate glasses to enhance the emission intensity and control the peak wavelength. PMID:20940756

Dai, Nengli; Xu, Bing; Jiang, Zuowen; Peng, Jingang; Li, Haiqing; Luan, Huaixun; Yang, Luyun; Li, Jinyan

2010-08-30

312

Two-photon-excited upconversion luminescence of Mn2+-doped germanate glass by infrared femtosecond laser irradiation  

NASA Astrophysics Data System (ADS)

We report on the upconversion luminescence of transition metal Mn ions doped germanate glass exited by an infrared femtosecond laser at room temperature. The luminescent spectra exhibited that the upconversion luminescence originates from the Mn2+ ions. The dependence of the fluorescence intensity on the pump power reveals that a two-photon excitation process dominates in the conversion of infrared radiation to the visible emission. It is suggested that the simultaneous absorption of two infrared photons produces the population of upper excited states, which leads to the characteristic visible emission. Furthermore, we observed that the photo-oxidation of Mn2+ ions to Mn3+ ions by measuring the absorption spectra of the Mn ions doped germanate glass before and after femtosecond laser irradiation.

Zhang, Yang; Li, Pengfei; Wang, Chengwei; Bao, Zongjie; Zhao, Quan-Zhong

2014-09-01

313

Laser stimulated piezoelectricity in Er3+ doped GeO2-Bi2O3 glasses containing silicon nanocrystals  

NASA Astrophysics Data System (ADS)

We report the first observation of the laser stimulated piezoelectricity in Er3+ doped GeO2-Bi2O3 glasses containing silicon nanocrystals, prepared using the simple well known melt quenching technique. Two split beams originated from the same nanosecond lasers were used for the performance of the bicolor laser treatment. The fundamental (? = 1064 nm) and the doubled frequency (? = 532 nm) signal of a pulsed nanosecond Nd:YAG laser, as the fundamental (? = 1540 nm) and the doubled frequency (? = 770 nm) signal of an Er:glass laser were used. The ratio of power densities between the fundamental and the doubled frequency beams has been varied from 4:1 to 8:1. This value was chosen to achieve the maximum output photoinduced piezoelectric response. The present photoinduced piezoelectricity effect opens a new road for obtaining optically operated piezoelectric devices in germanate composites doped with rare-earth ions.

Kassab, Luciana Reyes Pires; Camilo, Mauricio Eiji; da Silva, Diego Silverio; de Assumpção, Thiago Alexandre Alves; Fedorchuk, A. O.; Plucinski, K. J.

2014-12-01

314

Study of gamma induced defects in Nd doped phosphate glass using UV-Vis spectrophotometer and photophysics beamline on INDUS-1  

E-print Network

Nd doped phosphate glasses have been studied before and after gamma irradiation in order to understand the effect of glass composition and radiation induced defects on the optical properties of glasses. UV, Vis absorption and photoluminescence spectra of these glasses are found strongly dependent on the composition of glass matrix, particularly on the ratio of oxygen (O) and neodymium (Nd) concentration obtained from energy dispersive X-ray spectroscopic (EDX) measurement. Gamma irradiation of glass modifies the transmission below 700 nm due to generation of some new absorption bands corresponding to different types of defects. Observations indicate toward possibility of change in the valence state of Nd3+ to Nd2+ and generation of oxygen vacancies in glass matrix. EDX and X-ray photoelectron spectroscopic (XPS) measurements indicate change in the composition of glasses particularly decrease in the relative concentration of oxygen in glass samples after gamma irradiation.

Rai, V N; Jagtap, B N

2014-01-01

315

Spin Glasses and Frustrated Systems Mark van Schilfgaarde, Chairman Magnetic ordering in Re-doped a-Fe90Zr10  

E-print Network

Spin Glasses and Frustrated Systems Mark van Schilfgaarde, Chairman Magnetic ordering in Re-doped a 2052, Australia The magnetic properties of rhenium-doped a-Fe90Zr10 have been studied by magnetization, susceptibility, neutron depolarization, and Mo¨ssbauer spectroscopy and a magnetic phase diagram is presented

Ryan, Dominic

316

Effects of ultraviolet excitation on the spectroscopic properties of Sm3+ and Tb3+ doped aluminophosphate glasses  

NASA Astrophysics Data System (ADS)

Li2O-BaO-Al2O3-La2O3-P2O5 glasses optically activated with rare earth ions with the 4f5, and 4f8 electronic configuration (Sm3+ and Tb3+, respectively) were analyzed by Raman spectroscopy, absorption, excitation photoluminescence, decay curves and temperature dependent photoluminescence. The spectroscopic characteristics of the as-prepared and heat treated samples at temperatures below and above Tg were studied as well as their room temperature photometric properties under ultraviolet excitation. All the doped glasses exhibit typical signatures of the lanthanides in their trivalent charge state. For the samarium doped glass heat treated at 250 °C (doped glasses have much lower luminance intensity (around 0.3 Cd/m2) when compared with the 6-7 Cd/m2 observed for the terbium doped ones.

Nico, C.; Graça, M. P. F.; Elisa, M.; Sava, B. A.; Monteiro, R. C. C.; Rino, L.; Monteiro, T.

2013-10-01

317

Silver nanoparticles enhanced luminescence properties of Er{sup 3+} doped tellurite glasses: Effect of heat treatment  

SciTech Connect

Tellurite glasses doped Er{sup 3+} 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 Er{sup 3+} 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 {sup 4}I{sub 13/2}???{sup 4}I{sub 15/2} 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 Er{sup 3+} ions, whereas the quenching is ascribed to the energy transfer from Er{sup 3+} ions to silver NPs. Using the Mc Cumber method, absorption cross-section, calculated emission cross-section, and gain cross-section for the {sup 4}I{sub 13/2} ? {sup 4}I{sub 15/2} 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??m band broad and high-gain erbium-doped fiber amplifiers.

Fares, Hssen; Férid, Mokhtar [Laboratoire de Physico-Chimie des Matériaux Minéraux et leurs Applications, Centre National de Recherches en Sciences des Matériaux, B.P. 95 Hammam-Lif, 2050 (Tunisia); Elhouichet, Habib, E-mail: habib.elhouichet@fst.rnu.tn [Laboratoire de Physico-Chimie des Matériaux Minéraux et leurs Applications, Centre National de Recherches en Sciences des Matériaux, B.P. 95 Hammam-Lif, 2050 (Tunisia); Department of Physics, Sciences Faculty of Tunis, University Tunis ElManar 2092 (Tunisia); Gelloz, Bernard [Graduate School of Engineering, Nagoya University, 2-24-16 Furo-cho, Chikusa-ku, Nagoya, Aichi 464-8603 (Japan)

2014-09-28

318

Measurements of heating and energy storage in flashlamp-pumped Nd: YAg and Nd-doped phosphate laser glasses  

Microsoft Academic Search

The authors have experimentally measured the energy stored aNd the heat generated in flashlamp-pumped Nd:YAg and six different commercially available Nd-doped phosphate glasses. They find that the normalized heating parameter, defined as the heat deposited per unit stored energy, is 1.5-2 times the value expected from the known spectroscopy of the Nd ions in these hosts and the emission spectrum

M. Mangir; D. A. Rockwell

1986-01-01

319

Optical properties of undoped and Al-doped ZnO nanostructures grown from aqueous solution on glass substrate  

NASA Astrophysics Data System (ADS)

The paper presents the optical properties of undoped and aluminium-doped zinc oxide nanostructures grown on glass substrates using the hydrothermal method. The obtained ZnO-based nanostructures showed optical transmittance over 75% and low reflectance in the visible domain. The increasing of optical transmittance of Al-doped ZnO nanostructures with increased doping concentrations was observed. The optical constants such as index of refraction, extinction coefficient, dielectric constants and optical conductivity were determined using the transmission and the reflection at normal incidence of light in the wavelength range of 200-1100 nm. The band gap broadens with increasing dopant concentration from 2% to 4%. The obtained nanostructured layers with size in the range of subwavelength of visible light can act as anti-reflective coating that reduces reflectance based on the Moth Eye principle.

Mazilu, M.; Tigau, N.; Musat, V.

2012-09-01

320

Tm3+ and Tm(3+)-Ho3+ co-doped tungsten tellurite glass single mode fiber laser.  

PubMed

We investigated the ~2 ?m spectroscopic and lasing performance of Tm(3+) and Tm(3+)-Ho(3+) co-doped tungsten tellurite glass single mode fibers with a commercial 800 nm laser diode. The double cladding single mode (SM) fibers were fabricated by using rod-in-tube method. The propagation loss of the fiber was ~2.5 dB/m at 1310 nm. The spectroscopic properties of the fibers were analyzed. A 494 mW laser operating at ~1.9 ?m was achieved in a Tm(3+) doped 20 cm long fiber, the slope efficiency was 26%, and the laser beam quality factor M(2) was 1.09. A 35 mW ~2.1 ?m laser output was also demonstrated in a 7 cm long of Tm(3+)-Ho(3+) co-doped tungsten tellurite SM fiber. PMID:22535103

Li, Kefeng; Zhang, Guang; Wang, Xin; Hu, Lili; Kuan, Peiwen; Chen, Danping; Wang, Meng

2012-04-23

321

Luminescence of Eu(3+) doped SiO2 Thin Films and Glass Prepared by Sol-gel Technology  

NASA Technical Reports Server (NTRS)

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.

Castro, Lymari; Jia, Weiyi; Wang, Yanyun; Santiago, Miguel; Liu, Huimin

1998-01-01

322

Luminescent properties of Eu2+-doped BaGdF5 glass ceramics a potential blue phosphor for ultra-violet light-emitting diode  

NASA Astrophysics Data System (ADS)

Eu2+ doped transparent oxyfluoride glass ceramics containing BaGdF5 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 Gd3+ 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 Eu2+ 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 Gd3+ to Eu2+ ions, the energy transfer efficiency from Gd3+ to Eu2+ ions was discussed. In addition, the chromaticity coordinates of glass and glass ceramics specimens were also discussed, which indicated that the Eu2+ doped BaGdF5 glass ceramics may be used as a potential blue-emitting phosphor for UV-LED.

Zhang, Weihuan; Zhang, Yuepin; Ouyang, Shaoye; Zhang, Zhixiong; Wang, Qian; Xia, Haiping

2015-01-01

323

Infrared Study of Er3+/Yb3+ Co-Doped GeO2-PbO-Bi2O3 Glass  

PubMed Central

Heavy metal oxide glasses, containing bismuth and/or lead in their glass structure are new alternatives for rare eart (RE) doped hosts. Hence, the study of the structure of these vitreous systems is of great interest for science and technology. In this research work, GeO2-PbO-Bi2O3 glass host doped with Er3+/Yb3+ ions was synthesized by a conventional melt quenching method. The Fourier transform infrared (FTIR) results showed that PbO and Bi2O3 participate with PbO4 tetragonal pyramids and strongly distort BiO6 octahedral units in the glass network, which subsequently act as modifiers in glass structure. These results also confirmed the existence of both four and six coordination of germanium oxide in glass matrix. PMID:22942723

Bahari, Hamid-Reza; Sidek, Hj. A. A.; Adikan, Faisal Rafiq M.; Yunus, Wan M. M.; Halimah, Mohamed K.

2012-01-01

324

Infrared Study of Er(3+)/Yb(3+) Co-Doped GeO(2)-PbO-Bi(2)O(3) Glass.  

PubMed

Heavy metal oxide glasses, containing bismuth and/or lead in their glass structure are new alternatives for rare eart (RE) doped hosts. Hence, the study of the structure of these vitreous systems is of great interest for science and technology. In this research work, GeO(2)-PbO-Bi(2)O(3) glass host doped with Er(3+)/Yb(3+) ions was synthesized by a conventional melt quenching method. The Fourier transform infrared (FTIR) results showed that PbO and Bi(2)O(3) participate with PbO(4) tetragonal pyramids and strongly distort BiO(6) octahedral units in the glass network, which subsequently act as modifiers in glass structure. These results also confirmed the existence of both four and six coordination of germanium oxide in glass matrix. PMID:22942723

Bahari, Hamid-Reza; Sidek, Hj A A; Adikan, Faisal Rafiq M; Yunus, Wan M M; Halimah, Mohamed K

2012-01-01

325

Distribution of electric field and energy flux around the cracks on the surfaces of Nd-doped phosphate glasses  

SciTech Connect

We simulate and calculate numerically the electromagnetic field and energy flux around a surface crack of an Nd-doped phosphate laser glass by using the finite-difference time-domain method. Because of a strong interference between the incident wave and the total internal reflections from the crack and the glass surface, the electric field is redistributed and enhanced. The results show that the electric-field distribution and corresponding energy flux component depend sensitively on the light polarization and crack geometry, such as orientation and depth. The polarization of the incident laser beam relative to the crack surfaces will determine the profile of the electric field around the crack. Under TE wave incidence, the energy flux peak is always inside the glass. But under TM wave incidence, the energy flux peak will be located inside the glass or inside the air gap. For both incident modes, the light intensification factor increases with the crack depth, especially for energy flux along the surface. Because cracks on the polished surfaces are the same as the roots extending down, the probability for much larger intensification occurring is high. The results suggest that the surface laser-damage threshold of Nd-doped phosphate may decrease dramatically with subsurface damage.

Zhang Lei; Huang Li; Fan Sijun; Bai Gongxun; Li Kefeng; Chen Wei; Hu Lili

2010-12-10

326

Effects of Mg and Zn on the surface of doped melt-derived glass for biomaterials applications  

NASA Astrophysics Data System (ADS)

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.

Dietrich, E.; Oudadesse, H.; Lucas-Girot, A.; Le Gal, Y.; Jeanne, S.; Cathelineau, G.

2008-11-01

327

Morphology and orientation of ?-BaB2O4 crystals patterned by laser in the inside of samarium barium borate glass  

NASA Astrophysics Data System (ADS)

Nonlinear optical ?-BaB2O4 crystal lines (?-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 ?m/s), in which the laser focal position was moved gradually from the surface to the inside. The morphology, size, and orientation of ?-BBO crystals were examined from polarization optical microscope and birefringence imaging observations. It was demonstrated that c-axis oriented ?-BBO crystals with long lengths (e.g., 20 mm) were patterned in the inside of the glass. The morphology of ?-BBO in the cross-section of lines was a rectangular shape with rounded corners, and the volume of ?-BBO formed increased with increasing laser power and with decreasing laser scanning speed. The maximum depth in the inside from the surface for ?-BBO patterning increased with increasing laser power, e.g., Dmax~100 ?m at P=0.8 W, Dmax~170 ?m at P=0.9 W, and Dmax~200 ?m at P=1 W. The present study proposes that the laser-induced crystallization opens a new door for applied engineering in glassy solids.

Nishii, Akihito; Shinozaki, Kenji; Honma, Tsuyoshi; Komatsu, Takayuki

2015-01-01

328

Local devitrification of Dy 3+ doped Ba 2TiSi 2O 8 glass by laser irradiation  

NASA Astrophysics Data System (ADS)

The Ba 2TiSi 2O 8 (BTS) is a well known piezoelectric, ferroelectric and non-linear crystal. In this work, nanocrystals of BTS have been obtained by different thermal treatments of precursor glasses. The glasses were fabricated from BaO-TiO 2-SiO 2 and doped with Dy 2O 3 using the melt quenching method. Thermal treatment in an electrical furnace at 740 °C was used to obtain transparent glass ceramic samples, which are formed by an amorphous matrix containing BTS nanocrystals, with an average size of 35 nm confirmed by X-ray diffraction. Moreover, a localized area in the precursor glass has been irradiated by continuous wave (c.w.) Ar-laser or femtosecond (fs) pulsed laser. Evidence of the changes induced by laser irradiation is confirmed by spectroscopic comparison of irradiated regions with the precursor glass and glass ceramic samples. The emission spectra corresponding to the Dy 3+: 4F 9/2 ? 6H 13/2 (578 nm), 4F 9/2 ? 6H 11/2 (670 nm) and 4F 9/2 ? 6H 9/2 (757 nm) transitions were obtained under laser excitation at 473 nm. These measurements confirm the incorporation of the Dy 3+ ions into the BTS nanocrystals which produces an enhancement of luminescence and makes it an attractive material for optical amplification.

Martín, L. L.; Haro-González, P.; Martín, I. R.; Puerto, D.; Solís, J.; Cáceres, J. M.; Capuj, N. E.

2010-12-01

329

Control of the local devitrification on oxyfluoride glass doped with Er{sup 3+} ions under diode laser irradiation  

SciTech Connect

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.

Gonzalez-Perez, S.; Martin, I. R. [Departamento de Fisica Fundamental y Experimental, Electronica y Sistemas, Universidad de La Laguna, 38206 La Laguna, Tenerife (Spain); MALTA Consolider Team, Universidad de La Laguna, 38206 La Laguna, Tenerife (Spain); Jaque, D. [Departamento de Fisica de Materiales, Universidad Autonoma de Madrid, 28049 Madrid (Spain); Haro-Gonzalez, P. [Departamento de Fisica Fundamental y Experimental, Electronica y Sistemas, Universidad de La Laguna, 38206 La Laguna, Tenerife (Spain); Capuj, N. [Departamento de Fisica Basica, Universidad de La Laguna, 38206 La Laguna, Tenerife (Spain)

2010-11-15

330

Spectrometric analysis of different fluorophosphate glasses doped with Sm{sup 3+} ions for reddish-orange laser emission  

SciTech Connect

Optical properties of Sm{sup 3+} doped different fluorophosphate glasses have been synthesized and discussed. The J- O intensity parameters ?{sub ?} (?= 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.

Babu, S., E-mail: ratnakaramsvu@gmail.com; Balakrishna, A., E-mail: ratnakaramsvu@gmail.com; Ratnakaram, Y. C., E-mail: ratnakaramsvu@gmail.com [Department of Physics, Sri Venkateswara University, Tirupati-517502 (India)

2014-04-24

331

Spectrometric analysis of different fluorophosphate glasses doped with Sm3+ ions for reddish-orange laser emission  

NASA Astrophysics Data System (ADS)

Optical properties of Sm3+ doped different fluorophosphate glasses have been synthesized and discussed. The J- O intensity parameters ?? (?= 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 4G5/2?6H5/2, 6H7/2, 6H9/2 and 6H11/2 transitions. The nature of decay curve analysis was performed for the 4G5/2 level. These glasses are expected to give interesting application in field of optical devices.

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

2014-04-01

332

Mid-infrared spectroscopic properties and energy transfer of Er3+/Yb3+ co-doped bismuth germanate glass  

NASA Astrophysics Data System (ADS)

An Er3+/Yb3+ co-doped bismuth germanate glass is synthesized and analyzed. The radiative characteristics and mid-infrared spectroscopic properties are investigated under excitation of a conventional 980 nm laser diode. The prepared glass possesses higher spontaneous transition probability (68.82 s-1) and larger calculated emission cross-section (7.73 × 10-21 cm2) corresponding to the 4I11/2 ? 4I13/2 transition. The calculated energy migration coefficient (CDD) among Yb3+ ions is larger than the energy transfer coefficient (CDA) from Yb3+ to Er3+, indicating the energy transfer process assisted with energy migration. The excellent spectroscopic properties along with the outstanding thermal stability suggest that this glass may become an attractive host for developing solid state lasers operating in the mid-infrared range.

Zhao, Guoying; Wang, Shikai; Fan, Huiyan; Hu, Lili

2013-01-01

333

Mechanical and structural studies on sodium borosilicate glasses doped with Er 2O 3 using ultrasonic velocity and FTIR spectroscopy  

NASA Astrophysics Data System (ADS)

Sodium borosilicate glasses doped with different mol% content of Er 2O 3 have been prepared by rapid-quenching method. Ultrasonic velocities (both longitudinal and shear) measurements have been carried out at room temperature and at ultrasonic frequency of 4 MHz. Elastic moduli, Debye temperature, softening temperature, and Poisson's ratio have been obtained as a function of Er 2O 3 modifier content. Results show that the above-mentioned parameters have very slight change with the change of Er 2O 3 mol% content. Based on FTIR spectroscopy and theoretical (bond compression) model, quantitative analysis has been carried out in order to obtain more information about the structure of these glasses. The study indicated that the structure of these glasses is mainly composed of SiO 4 units with four bridging oxygens (Q 4), and with three bridging and one nonbridging oxygens (Q 3).

Gaafar, M. S.; Marzouk, S. Y.

2007-01-01

334

Mirrorless optical bistability in a semiconductor-doped-glass plate as a result of oblique incidence  

NASA Astrophysics Data System (ADS)

A procedure to obtain optical bistability in a third-order nonlinear film (or parallel plate) of low refractive index without any external mirrors is investigated both theoretically and experimentally. If an s-polarized light is incident obliquely at a large angle of incidence on the film, the generation of optical bistability can be expected because of the resulting increase in the reflectivity at the surfaces. A rigorous analysis of the stationary transmission characteristics of the nonlinear film is done for both positive and negative nonlinear coefficients with a plane-wave model. In the experimental demonstration, a CdSx Se1-x-doped glass (Hoya Y-52) plate and a cw Ar+ laser are used as the nonlinear material and the light source, respectively. It is shown that three operations of optical bistability, optical limiting, and differential gain can be easily obtained through adjustment of the angle of incidence as an initial detuning. The measured nonlinearity is thermal, and the magnitude and sign of the nonlinear refractive index are determined.

Ogusu, Kazuhiko; Kaneko, Yoshinori; Ishikawa, Kenji

1995-06-01

335

Structural and Optical Studies on Dy{sup 3+} Doped Boro-Tellurite Glasses  

SciTech Connect

Dy{sup 3+} doped Boro-tellurite glasses were prepared by following melt quenching technique with the chemical composition (69-x)H{sub 3}BO{sub 3}+xTeO{sub 2}+15Mg{sub 2}CO{sub 3}+15K{sub 2}CO{sub 3}+1Dy{sub 2}O{sub 3} by varying the tellurium dioxide content as (x = 0, 10, 20, 30 and 40 wt%). The structural and optical properties have been studied through FTIR, absorption and emission spectra. The UV-vis-NIR absorption spectra were used to calculate the oscillator strength, bonding parameters ({beta}-bar and {delta}), Judd-Ofelt intensity parameters ({Omega}{sub {lambda}}, {lambda} = 2, 4 and 6). The Y/B ratio has been discussed from the luminescence spectra for the excited states corresponding to {sup 4}F{sub 9/2}{yields}{sup 6}H{sub 11/2}, {sup 6}H{sub 13/2}, and {sup 6}H{sub 15/2} transitions. The structural and optical properties corresponding to the compositional changes are discussed and reported.

Maheshvaran, K.; Marimuthu, K. [Department of Physics, Gandhigram Rural Institute -Deemed University, Gandhigram - 624 302 (India)

2011-07-15

336

Study of interaction of high-power Ar$^+$ laser beam with Ag$^+$-doped glass  

E-print Network

In this work, we have investigated the interaction of a high-power Ar$^+$ laser beam, in a continuous multi-line regime, with Ag$^+$-doped glass samples. The samples were subjected to the irradiation after the ion-exchange step. As a result of the irradiation, a peak appears in the absorption spectrum; its evolution depends on both the exposure time and the laser beam power. Interaction of the beam with the clusters causes them break into smaller ones which has been confirmed by optical absorption spectroscopy. Depending on the increment steps of the laser-beam power, different results are obtained. It is found that, in addition to the fragmentations of the nano-clusters, clusters of micro-meter size ($d\\sim 3\\mu m$) are formed in the sample, if the laser power is increased in a fast regime. The fragmentation processes have been explained in the framework of the density-functional theory with stabilized jellium model.

Nahal, A; Payami, M

2003-01-01

337

Mechanical and thermal behaviors of nitrogen-doped Zr-Cu-Al-Ag-Ta--An alternative class of thin film metallic glass  

NASA Astrophysics Data System (ADS)

Super-plasticity and nano-scale surface roughness make thin film metallic glass (TFMG) a candidate for master mold of micro/nano imprint technique. Meanwhile, better mechanical properties of TFMG undoubtedly expand the life time of master mold. In this study, nitrogen is doped into Zr-based TFMG to exhibit the hardness higher than 10 GPa. Different from elements used to be doped into metallic glass, the role of nitrogen atoms plays in metallic glass is distinct and vital owing to its strong electronegativity. From the correlation of thermal and mechanical behavior, the role and effect of nitrogen in Ta-Zr-Cu-Al-Ag TFMG is discussed and proposed.

Chen, Pao-Sheng; Chen, Hsien-Wei; Duh, Jenq-Gong; Lee, Jyh-Wei; Shian-Ching Jang, Jason

2012-10-01

338

Synthesis and optical characteristics of Sm3+-doped 15K2O-15Nb2O5-70TeO2 glass ceramics  

NASA Astrophysics Data System (ADS)

We investigate the crystallinity and the optical properties of pure and Sm3+-doped 15K2O-15Nb2O5-70TeO2 glass ceramics after heat treatment. We prepare pure and 1 mol% Sm3+-doped 15K2O-15Nb2O5-70TeO2 glasses by using the conventional melt-quenching method. After annealing at 390 °C and 410 °C, respectively, we characterize the crystallinity of the glasses. We examine the chemical bonding states of the ions and the optical properties by taking absorption, excitation, and emission spectra. We show that Sm3+-doped 15K2O-15Nb2O5-70TeO2 glass ceramics after heat treatment are excellent red-orange-emitting phosphors under near UV excitation.

Hong, K. S.; Cha, Yu-Jung; Ha, Myoung Gyu; Jeong, Euh Duck; Bae, Jong Seong; Kim, Hyun Gyu; Yang, Ho-Soon

2014-06-01

339

Eu-doped B2O3-ZnO-PbO glass phosphor powders with spherical shape and fine size prepared by spray pyrolysis  

NASA Astrophysics Data System (ADS)

Eu-doped B2O3-ZnO-PbO glass phosphor powders with spherical shape and fine size were directly prepared by spray pyrolysis. The glass phosphor powders prepared at a temperature of 1100°C had broad XRD peak at around 28°. One glass phosphor powder was formed from one droplet at the preparation temperature range from 900 to 1100°C. The mean size of the glass phosphor powders was 0.75 ?m. The glass transition temperature ( T g ) of the glass phosphor powders prepared by spray pyrolysis was 378.5°C. The excitation spectrum of the glass phosphor powders prepared at the optimum preparation temperature of 1100°C had bands at 362, 381, 392, 463, 525, and 532 nm. The glass phosphor powders had emission spectra with bands at 579, 614, and 653 nm. The glass phosphor powders with doping concentration of Eu of 7 wt% had the maximum photoluminescence intensity. The glass phosphor layer formed from the glass phosphor powders had high transparencies above 90%.

Hong, Seung Kwon; Koo, Hye Young; Ko, You Na; Kim, Jung Hyun; Yi, Jang Heui; Kang, Yun Chan

2010-03-01

340

Characteristics of solid-state batteries with zinc/cadmium halide-doped silver phosphate glasses as electrolytes  

NASA Astrophysics Data System (ADS)

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.

Das, S. S.; Baranwal, B. P.; Gupta, C. P.; Singh, Punita

341

Optical properties of As2S3 and As2Se3 glasses doped with Dy, Sm, and Mn  

NASA Astrophysics Data System (ADS)

The effect of low amounts of dysprosium, samarium and manganese (0.1-0.5 at.%) on structure and optical properties of chalcogenide glassy semiconductors As2S3 and As2Se3 is investigated. The fundamental absorption edge shifts to longer wavelength with doping; the largest shift was observed for As2S3 glasses doped with Dy and Mn. A correlation of the properties with medium range order and electronegativity of impurity atoms was revealed. Photodarkening relaxation under light exposure of a-As2Se3 amorphous films doped with 0.5 at.% of metals Sn, Mn, Sm and Dy was studied in dependence on the impurity and thermal treating. Both factors reduce photodarkening and the degree of reduction depends on the sort of impurity. The relaxation process may be described by a stretched exponential with the dispersive parameter 0.5glasses.

Andriesh, Andrei M.; Iovu, Mihai S.; Shutov, Sergiu D.; Seddon, Angela B.; Furniss, David; Popescu, Mihai A.

2001-06-01

342

Enhanced green and red upconversion emissions in Er3+-doped boro-tellurite glass containing gold nanoparticles  

NASA Astrophysics Data System (ADS)

Increasing the cross-section of upconversion emissions from the rare earth ions doped materials is a challenging issue. In this work, we report on the enhancement of the up-converted emissions of Er3+-doped boro-tellurite glasses containing gold nanoparticles which have been prepared by a conventional melt-quench technique. Seven absorption bands and three emission lines are observed using the UV-Vis-IR and photoluminescence spectroscopic techniques, respectively. Red emission is enhanced up to 30 times in a sample having 1 wt% of Au nanoparticles. The presence of the gold nanoparticles with average size of ?5.74 nm is confirmed by transmission electron microscopy and corresponding surface plasmon band is observed at 630 nm in a singly-doped Au-nanoparticles embedded glass sample. A model to determine the enhancement factor of the emissions is suggested which could not describe the phenomenon for high concentrations of nanoparticles. Enhancement is attributed to the increased local field around the metal, and the results are discussed in details.

Dousti, M. Reza; Amjad, Raja J.; Mahraz, Zahra Ashur S.

2015-01-01

343

Copper-doped borosilicate bioactive glass scaffolds with improved angiogenic and osteogenic capacity for repairing osseous defects.  

PubMed

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. PMID:25534470

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

2015-03-01

344

Pr3+-doped heavy metal germanium tellurite glasses for irradiative light source in minimally invasive photodynamic therapy surgery.  

PubMed

Pr3+-doped medium-low phonon energy heavy metal germanium tellurite (NZPGT) glasses have been fabricated and the intense multi-peak red fluorescence emissions of Pr3+ are exhibited. Judd-Ofelt parameters ?2 = 3.14 × 10(-20)cm(2), ?4 = 10.67 × 10(-20)cm(2) and ?6 = 3.95 × 10(-20)cm(2) indicate a high asymmetrical and covalent environment in the optical glasses. The spontaneous emission probabilities A(ij) corresponding to the 1D2?3H4, 3P0?3H6, and 3P0?3F2 transitions are derived to be 1859.6, 6270.1 and 17276.3s(-1), respectively, and the relevant stimulated emission cross-sections ?(em) are 5.20 × 10(-21), 14.14 × 10(-21) and 126.77 × 10(-21)cm(2), confirming that the effectiveness of the red luminescence in Pr3+-doped NZPGT glasses. Under the commercial blue LED excitation, the radiant flux and the quantum yield for the red fluorescence of Pr3+ are solved to be 219?W and 11.80%, respectively. 85.24% photons of the fluorescence in the visible region are demonstrated to be located in 600-720nm wavelength range, which matches the excitation band of the most photosensitizers (PS), holding great promise for photodynamic therapy (PDT) treatment and clinical trials. PMID:23388997

Yang, J; Chen, B J; Pun, E Y B; Zhai, B; Lin, H

2013-01-14

345

Influence of yttrium ions on the emission transfer features of Ce3+/Yb3+ co-doped lithium silicate glasses  

NASA Astrophysics Data System (ADS)

Optical absorption and photoluminescence spectra (PL) of the glasses possessing compositions (49 - x) Li2O-x Y2O3-50 SiO2:1.0 Ce2O3/1.0Yb2O3 and (49 - x) Li2O-x Y2O3-50 SiO2:(0.5 Ce2O3 + 0.5 Yb2O3) with x varying from 5 to 15 mol% were studied. The PL spectra of Ce3+ doped glasses excited at 360 nm exhibited two broad parity allowed 5d(2D) ? 4f(2F5/2,7/2) bands in the blue spectral region, whereas the spectra of Yb3+ doped glasses excited at 900 nm exhibited a broad emission band centered at about 980 nm due to 2F5/2 ? 2F7/2 transition. A significant enhancement in the intensity of NIR emission is observed due to the sensitization with Ce3+ ions. The increase in the rate of energy transfer from Ce3+ to Yb3+ could be observed with increasing Y2O3 content. The reasons for such improvement have been discussed within a framework of structural modifications taking place in the vicinity of Yb3+ ions.

Ramesh Babu, N. Ch.; Srinivasa Rao, Ch.; Naga Raju, G.; Ravi Kumar, V.; Kityk, I. V.; Veeraiah, N.

2012-06-01

346

Three-dimensional endothelial cell morphogenesis under controlled ion release from copper-doped phosphate glass.  

PubMed

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 10mol%). 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

Stähli, Christoph; James-Bhasin, Mark; Nazhat, Showan N

2015-02-28

347

Study of a silicate glass doped with Cd-S-Se nanocrystals and optical waveguides formed with Cs-K ion exchange  

NASA Astrophysics Data System (ADS)

Zinc-boron-silicate glass doped with cadmium sulfide-selenide was synthesized, and arising and growth of Cd-S-Se microcrystals in the glass matrix under annealing was studied. The annealing dependant shift of absorption edge of the glass samples was demonstrated. Transmission electron microscopy proved that quantum confinement effect was an origin of the shifts. Growth of the microcrystals was followed by increase of their dispersion. Also the growth led to transformation of structure of the microcrystals from cubical to hexagonal. Cesium-potassium ion exchange in the SDG was applied to optical waveguides formation. Differences of the alkaline ion profiles in the glass samples annealed differently were observed.

Lipovskii, Andrey A.; Nikonorov, Nikolai V.; Kharchenko, Mikhail V.; Sitnikova, A. A.

1994-10-01

348

Surface silver-doping of biocompatible glasses to induce antibacterial properties. Part II: Plasma sprayed glass-coatings.  

PubMed

A 57% SiO(2), 3% Al(2)O(3), 34% CaO and 6% Na(2)O glass (SCNA) has been produced in form of powders and deposited by plasma spray on titanium alloy and stainless steel substrates. The obtained coatings have been subjected to a patented ion-exchange treatment to introduce silver ions in the surface inducing an antibacterial behavior. Silver surface-enriched samples have been characterized by means of X-ray diffraction, SEM observation, EDS analysis, in vitro bioactivity tests, leaching tests by GFAAS (graphite furnace atomic adsorption spectroscopy) analyses, cells adhesion and proliferation, and antibacterial tests using Staphylococcus Aureus strain. In vitro tests results showed that the modified samples acquired an antimicrobial action against tested bacteria maintaining unaffected the biocompatibility of the glass. Furthermore the ion-exchange treatment can be successfully applied to glass-coated samples without affecting the properties of the coatings; the simplicity and reproducibility of the method make it suitable for glass or glass-ceramic coatings of different composition in order to produce coated devices for bone healing and/or prostheses, able to reduce bacterial colonization and infections risks. PMID:18987953

Miola, M; Ferraris, S; Di Nunzio, S; Robotti, P F; Bianchi, G; Fucale, G; Maina, G; Cannas, M; Gatti, S; Massé, A; Vitale Brovarone, C; Verné, E

2009-03-01

349

In situ isothermal monitoring of the enhancement and quenching of Sm3+ photoluminescence in Ag co-doped glass  

NASA Astrophysics Data System (ADS)

A novel in situ concurrent photoluminescence and absorption microspectroscopy technique is proposed for the real-time monitoring of the optical properties of rare-earth and noble metal co-doped dielectrics during isothermal processing. The technique has been successfully applied to an Ag and Sm co-doped phosphate glass, where both enhancement and quenching regimes of Sm3+ luminescence have been observed well separated in time, practical for an 'optical tuning' of the solid-state luminescent material. Further, relating simultaneously the luminescence with the time evolution in optical absorption allowed for discerning the effects of Ag non-plasmonic clusters as enhancers and nanoparticles as quenchers. Opportunities come forward for studying a variety of systems with relevance to a wide range of applications.

Jiménez, José A.; Sendova, Mariana

2012-09-01

350

Osteoblastic differentiation under controlled bioactive ion release by silica and titania doped sodium-free calcium phosphate-based glass.  

PubMed

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

Shah Mohammadi, Maziar; Chicatun, Florencia; Stähli, Christoph; Muja, Naser; Bureau, Martin N; Nazhat, Showan N

2014-09-01

351

Three-photon near-infrared quantum cutting in Tm{sup 3+}-doped transparent oxyfluoride glass ceramics  

SciTech Connect

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.

Yu, D. C.; Zhang, J. P.; Chen, Q. J.; Zhang, W. J.; Yang, Z. M.; Zhang, Q. Y. [State Key Laboratory of Luminescence Materials and Devices, and Institute of Optical Communication Materials, South China University of Technology, Guangzhou 510641 (China)

2012-10-22

352

Coherent quantum control of green emission in Er3+-doped glass by ?-phase-shaped ultrashort laser pulses  

NASA Astrophysics Data System (ADS)

We experimentally and theoretically study the coherent quantum control of green emission in Er3+-doped glass by ?-phase-shaped 800-nm femtosecond laser pulses. The experimental results show that the green emission intensity is enhanced over the transform-limited pulse by ?-phase-shaped pulses as the laser field increases to several 1012 W/cm2. Coherent control of multiphoton absorption is studied based on the fourth-order perturbation theory, and the theoretical results accord well with the experimental observations.

Cheng, Wenjing; Jia, Tianqing; Shang, Xiaoying; Zhang, Shian; Ma, Jing; Feng, Donghai; Sun, Zhenrong; Qiu, Jianrong

2014-02-01

353

Photoluminescence enhancement by gold nanoparticles in Eu3+ doped GeO2-Bi2O3 glasses  

NASA Astrophysics Data System (ADS)

We report large photoluminescence (PL) enhancement in Eu3+-doped GeO2-Bi2O3 glasses containing gold nanoparticles (NPs). Growth of ?1000% in the PL intensity corresponding to the Eu3+ transition D50?F72, at 614 nm, was observed in comparison with a reference sample that does not contain gold NPs. Other PL bands from 580 to 700 nm are also enhanced. The enhancement of the PL intensity is attributed to the increased local field in the Eu3+ locations due to the presence of the NPs and the energy transfer from the excited NPs to the Eu3+ ions.

Kassab, Luciana R. P.; da Silva, Diego S.; de Almeida, Ricardo; de Araújo, Cid B.

2009-03-01

354

Frequency upconversion in Er3+ doped PbO -GeO2 glasses containing metallic nanoparticles  

NASA Astrophysics Data System (ADS)

The authors report the infrared-to-visible frequency upconversion (UPC) process in Er3+ doped PbO-GeO2 glasses containing silver nanoparticles (NPs) with an average diameter of 2.2nm. The absorption spectra of the samples present a band centered at 470nm due to the surface plasmons associated with the NPs. The intensity of the band grows with increasing NP concentration. The experiments were performed by exciting the samples with a 980nm diode laser and observing the UPC emissions in the red-green region. The enhanced UPC intensity is attributed to the local field effect in the proximity of the NPs.

da Silva, Davinson Mariano; Kassab, Luciana Reyes Pires; Lüthi, Stefan R.; de Araújo, Cid B.; Gomes, Anderson S. L.; Bell, Maria José Valenzuella

2007-02-01

355

Application of glass particles doped by Zn(+2) as an antimicrobial and atoxic compound in LLDPE and HDPE.  

PubMed

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

Santos, M F; Machado, C; Tachinski, C G; Júnior, J F; Piletti, R; Peterson, M; Fiori, M A

2014-06-01

356

Polaronic behavior of MnO doped LiI-AgI-B2O3 glass  

NASA Astrophysics Data System (ADS)

The ac electrical conductivity and dielectric constant of LiI-AgI-B2O3 glass doped with 0.1 mol. % MnO were investigated in the frequency range from 1 Hz to 1 MHz and the temperature range from 5 K to 450 K. At temperatures below 450 K, an ac conductivity and dielectric constant follow the universal dielectric response (UDR), being typical for hopping or tunneling of localized charge carriers. A detailed analysis of the temperature dependence of the UDR parameter s in terms of the theoretical model for tunneling of small polarons revealed that, below 450 K, this mechanism governs the charge transport in this glass. The comparison of the values of characteristic coefficients W? and Eac determined by two different methods confirms the polaronic behavior of this system.

Filipi?, C.; Moguš-Milankovi?, A.; Pavi?, L.; Srilatha, K.; Veeraiah, N.; Levstik, A.

2012-10-01

357

Enhanced upconverted emission in Yb3+/Er3+ co-doped GdPO4 transparent glass ceramics  

NASA Astrophysics Data System (ADS)

Yb3+/Er3+ co-doped transparent glass ceramics (GC) containing GdPO4 nanocrystals have been successfully fabricated using a conventional melt-quenching method with subsequent heat treatment. The structural and the luminescence properties were investigated by X-ray diffraction, transmission electron microscopy, and upconverted emission spectra. Under the excitation of a 980 nm diode laser, the total upconverted emission in GC as well as the Green/Red emission intensity ratio in the GC670 sample was enhanced compared to that in the precursor glass, indicating that Er3+ ions have entered into GdPO4 nanocrystals after crystallization. Our results also show that the Green/Red emission intensity ratio of GC is closely related to crystallinity of the samples. The outstanding properties of GdPO4-based transparent GC provide a promising candidate for wide application fields, such as in all-solid-state upconversion lasers and optical fibers.

Liao, Liqing; Jiang, Sha; Zhou, Shaoshuai; Wei, Xiantao; Duan, Changkui; Yin, Min; Chen, Yonghu

2014-09-01

358

The effect of La2O3 in Tm3+-doped germanate-tellurite glasses for ~2??m emission  

PubMed Central

A germanate-tellurite glass (GeO2-TeO2-K2O-Nb2O5-La2O3) with thulium doping has been investigated for application as a laser material around 2.0??m regions. Under the 808?nm laser diode pumped, intense 1.8??m emission is obtained. Based on the absorption spectra, radiative properties are predicted using Judd-Ofelt theory. The maximum value of emission cross-section of Tm3+ around 1.8??m can reach 1.46 × 10?20?cm2, which indicated that the germanate-tellurite glass may provide high gain as a good medium for efficient 1.8??m laser system. PMID:24918516

Peng, Ya-Pei; Yuan, Xinqiang; Zhang, Junjie; Zhang, Long

2014-01-01

359

The electric transport properties of Al-doped ZnO/BiFeO3/ITO glass heterostructure  

NASA Astrophysics Data System (ADS)

BiFeO3 (BFO) and 4 wt. % Al-doped ZnO (ZAO) layers were grown on indium tin oxide (ITO) glass substrate using a pulsed laser deposition (PLD) method. I-V curves of the ZAO/BFO/ITO glass structure were investigated over the temperature range from 60 to 240 K. Analysis of the leakage current demonstrates that Poole-Frenkel emission is the dominant mechanism in our sample. The relations between resistance and temperature at positive and negative bias voltages are different, and the difference arises from the ferroelectric switching in BFO and the interfacial depletion layer between the semiconducting and the ferroelectric layers. Magnetoresistance (MR) effect is observed and the negative MR is related to the electron spin-dependent scattering and the interface resistance of the heterostructure.

Fan, Fei; Chen, Changle; Luo, Bingcheng; Jin, Kexin

2011-04-01

360

Laser-induced radial birefringence and spin-to-orbital optical angular momentum conversion in silver-doped glasses  

SciTech Connect

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.

Amjad, Jafar Mostafavi; Khalesifard, Hamid Reza [Department of Physics, Institute for Advanced Studies in Basic Sciences (IASBS), 45137-66731 Zanjan (Iran, Islamic Republic of); Slussarenko, Sergei; Karimi, Ebrahim; Santamato, Enrico [Dipartimento di Scienze Fisiche, Universita di Napoli ''Federico II'', Complesso Universitario di Monte S. Angelo, 80126 Napoli (Italy); Marrucci, Lorenzo [Dipartimento di Scienze Fisiche, Universita di Napoli ''Federico II'', Complesso Universitario di Monte S. Angelo, 80126 Napoli (Italy); CNR-SPIN, Complesso di Monte S. Angelo, 80126 Napoli (Italy)

2011-07-04

361

Gain and Noise Figure of a Double-Pass Waveguide Amplifier Based on Er/Yb-Doped Phosphate Glass  

NASA Astrophysics Data System (ADS)

A waveguide amplifier is fabricated by Ag+-Na+ two-step ion exchange on Er/Yb-doped phosphate glass. The spectroscopic performance of glass and the properties of channel waveguide are characterized. A double-pass configuration is adopted to measure the gain and noise figure (NF) of the waveguide amplifier, and the comparison of gain and NF for the single and double-pass configuration of the waveguide amplifier is presented. The results show that the double-pass configuration can make the gain increase from 8.8 dB (net gain 2.2 dB/cm) of the single-pass one to 14.6 dB (net gain 3.65 dB/cm) for small input power at 1534 nm, and the NF are all lower than 5.5 dB for both the configurations.

Jin, Guo-Liang; Shao, Gong-Wang; Mu, Huan; Hu, Li-Li; Li, Qu

2005-11-01

362

Multicolor frequency upconversion luminescence in europium/terbium co-doped ytterbium-sensitized fluorogermanate glass excited at 980 nm  

NASA Astrophysics Data System (ADS)

Glass 80GeO3:10PbF2:10CdF2 triply-doped with europium, terbium, and ytterbium phosphors were synthesized and the energy upconversion luminescence emission properties investigated as a function of NIR excitation power, rare-earth ions content combination, and glass phosphor composition. Multicolor visible luminescence with main emissions peaked around 490, 545, 590, 610, 650, and 700 nm was observed when samples were excited by a diode laser at 980 nm. The up-conversion excitation mechanism for both Eu3+, and Tb3+ excited-states emitting levels was achieved via phononassisted cooperative energy-transfer from pairs of excited Yb3+ ions. White-light emission with CIE-1931 coordinates in the region of low color correlated temperature was obtained for appropriate combination of rare-earth ions content.

Silva, James R.; Gouveia-Neto, Artur S.; Bueno, Luciano A.

2014-02-01

363

Properties of Transparent Conductive Ga-Doped ZnO Films on Glass, PMMA and COP Substrates  

NASA Astrophysics Data System (ADS)

The dependences of the structural, optical and electrical properties of highly transparent conductive Ga-doped ZnO (GZO) films on thickness have been studied. GZO films were prepared on unheated glass, polymethyl methacrylate (PMMA) and cyclo olefin polymer (COP) substrates by ion plating deposition with direct-current arc discharge. Polycrystalline GZO films with good adherence to a substrate having a (0002) preferred orientation have been obtained. Very little difference was found between the resistivity values of the GZO films on the glass substrate and those of the GZO films on the different polymer substrates, at any given film thickness. On both plastic substrates, the resistivity of the GZO films decreased from 2×10-3 to 5×10-4?cm with increasing film thickness.

Yamamoto, Tetsuya; Miyake, Aki; Yamada, Takahiro; Morizane, Toshiyuki; Arimitsu, Tetsuhiro; Makino, Hisao; Yamamoto, Naoki

364

White light luminous properties and energy transfer mechanism of rare earth ions in Ce3+/Tb3+/Sm3+ co-doped glasses  

NASA Astrophysics Data System (ADS)

We report on a kind of Ce3+/Tb3+/Sm3+ co-doped borosilicate glasses which can emit white light luminescence combined with red, green and blue fluorescence. In this manuscript, the energy transfer mechanism between Ce3+ and Tb3+ ions, Ce3+ and Sm3+ ions, and Tb3+ and Sm3+ ions is discussed by analysis of the steady and transient luminescence spectra of the doped ions. Based on the energy transfer mechanism, the near-ideal white light emission from the Ce3+/Tb3+/Sm3+ co-doped glasses with the color coordinate ( x=0.335, y=0.337) has been observed under 350-nm excitation. Meanwhile, the calculated parameters such as color rendering index (78-81) and color temperature (4717-5372 K), characterizing luminous properties, show that the glasses can be potential candidates for displays and lighting.

Chen, Qiaoqiao; Dai, Nengli; Liu, Zijun; Chu, Yingbo; Ye, Baoyuan; Li, Haiqing; Peng, Jinggang; Jiang, Zuowen; Li, Jinyan; Wang, Fang; Yang, Luyun

2014-06-01

365

Concentration dependent structural and spectroscopic properties of Sm3+/Yb3+ co-doped sodium tellurite glass  

NASA Astrophysics Data System (ADS)

Tuning the optical and structural behaviors of tellurite glasses with controlled dopants is the key issue in solid state lasers and amplifiers. Sm3+/Yb3+ co-doped sodium tellurite glasses are prepared by the melt quenching technique and characterized using XRD, FTIR and DTA, optical absorption and luminescence techniques. The XRD spectra reveals the amorphous nature of glasses and the presence of functional groups such as Te-O bond in trigonal bipyramids (TeO4), Te-O bending vibration of the trigonal pyramids (TeO3) and non-hygroscopic nature of the glasses are confirmed from FTIR spectra. The DTA measurement shows the thermal stability lies in the range of 106-123. The UV-vis-NIR spectra exhibit eight absorption bands corresponding to the transition from ground level 6H5/2 to the various excited state of Sm3+ ions and the broad absorption band in the range of ~825-1100 nm is ascribed to the large contribution of the absorption from 2F7/2?2F5/2 transition of Yb3+ ion. The experimental oscillator strengths calculated from the absorption spectra are used to evaluate three phenomenological Judd-Ofelt (J-O) intensity parameters ?? (?=2, 4 and 6). Emission spectra consist of four bands 4G5/2?6H7/2 (moderate green) 4G5/2?6H5/2 (intense orange), 4G5/2?6H7/2 (moderate orange-yellow) and 4G5/2?6H11/2 (feeble red). The J-O parameters are employed to calculate radiative parameters such as transition probability (AR), branching ratio (BR), effective bandwidth (?eff) and stimulated emission cross-section ?(?p) of these emission transition of trivalent samarium ion. The optical band gap energy value (Eopt) and Urbach energy values (?E) are calculated and compared. The concentration dependent spectroscopic behavior of Sm3+-doped and Sm3+/Yb3+co-doped glasses is understood. Our systematic study may contribute towards the development of optical device fabrication.

Nawaz, Fakhra; Sahar, Md. Rahim; Ghoshal, S. K.; Awang, Asmahani; Ahmed, Ishaq

2014-01-01

366

Laser-diode-excited intense luminescence and green-upconversion in erbium-doped bismuth-germanate-lead glasses.  

PubMed

We investigate the spectroscopic properties of the 1.5-microm emission from the (4)I(13/2)-->(4)I(15/2) transition of Er(3+) ions in bismuth-germanate-lead glasses for applications in broadband fiber amplifiers. The emission peak locates at 1532nm with a full width at half-maximum (FWHM) of approximately 65nm. The measured lifetime and the calculated emission cross-section of this transition are 3.3ms and 8.66x10(-21)cm(2), respectively. IR-to-green-upconversion occurs simultaneously upon excitation of the 1.5-microm emission with a commercially available 980nm laser diode. Effects of PbF(2) content on the thermal stability, structure and spectroscopic properties of Er(3+)-doped bismuth-germanate-lead glasses have been examined. We find that the substitution with PbF(2) provides a couple of potentials: shortening the UV cutoff band and decreasing the phonon energy of host glasses. Codoping of Yb(3+) significantly enhances both the green-upconversion and 1.5-microm emission intensity by means of a nonradiative Yb(3+)-->Er(3+) energy transfer. Energy transfer processes and nonradiative phonon-assisted decays could account for the population of the (2)H(11/2) level, which is an emitting level of the green-upconversion of Er(3+). The results indicate the possibility towards the development of bismuth-germanate-lead based glasses as photonics devices. PMID:17433763

Yang, G F; Zhang, Q Y; Li, T; Shi, D M; Jiang, Z H

2008-01-01

367

Up-conversion emission tuning in triply-doped Yb3+/Tm3+/Er3+ novel fluoro-phosphate glass and glass-ceramics  

NASA Astrophysics Data System (ADS)

New Yb3+, Er3+ and Tm3+ triply doped fluoro-phosphate glasses belonging to the system NaPO3-YF3-BaF2-CaF2 have been prepared by the classical melt-casting technique. Glasses containing up to 10 wt.% of rare-earth ions fluorides have been obtained and characterized by using differential scanning calorimetry (DSC), UV-visible-near-infrared spectroscopy and up-conversion emission spectroscopy under excitation with a 975 nm laser diode. Transparent and optically homogeneous glass-ceramics have been reproducibly obtained by appropriate heat treatment in view to manage the red, green and blue emissions upon 975 nm laser excitation. According to the applied thermal heat-treatment, a large enhancement of intensity of the up-conversion emission - from 10 to 160 times higher - has been achieved in the glassceramics compared to that of glasses, suggesting incorporation of the rare-earth ions into the crystalline phase. Furthermore, a large range of color rendering has been observed in these materials by controlling the laser excitation power and material crystallization rate. Time-resolved luminescence experiments as well as X-ray diffractometry and scanning electron microscopy techniques have been employed in order to understand and correlate the multicolor emission changes to the crystallization behavior of this material. A progressive phase transformation of the fluorite-type CaF2-based nanocrystals initially generated was observed along with increasing heat-treatment time, thus modifying the rare earth ions spectroscopic features.

Ledemi, Yannick; Trudel, Andrée.-Anne; Rivera, Victor A. G.; Messaddeq, Younes

2014-03-01

368

Broadband near-IR emission and temperature dependence in Er/Tm co-doped Bi2O3-SiO2-Ga2O3 glasses  

NASA Astrophysics Data System (ADS)

The broadband near-IR emission has been investigated in a series of Er/Tm co-doped Bi2O3-SiO2-Ga2O3 (BSG) glasses with 800 nm laser diode as an excitation source. A broadband emission extending from 1350 to 1650 nm with a full width at half maximum (FWHM) around 165 nm is obtained in 0.2 wt% Er2O3 and 1.0 wt% Tm2O3 co-doped BSG glass. The fluorescence decay curves of glasses are measured and maximum energy transfer efficiency from Er3+ to Tm3+ reaches 71% when Tm3+ concentration is 1.0 wt%. The temperature dependence of the broadband emission spectra in Er3+-Tm3+ co-doped BSG glass is also recorded to further understand the energy-transfer processes between Er3+ and Tm3+. The present work suggests that Er/Tm co-doped BSG glasses can be a potential candidate for broadband integrated amplifier.

Zhao, Guoying; Tian, Ying; Wang, Shikai; Fan, Huiyan; Hu, Lili

2012-12-01

369

2.7 ?m emission properties of Er3+ doped tungsten-tellurite glass sensitized by Yb3+ ions.  

PubMed

With a 980 nm laser diode (LD) pumped, the sensitized effect of Yb(3+) ions on 2.7 ?m emission properties and energy transfer mechanism in Yb(3+)/Er(3+) co-doped tungsten-tellurite glass were investigated in present paper. Based on absorption spectra, Judd-Ofelt parameters and radiative transition probabilities were calculated and analyzed. The emission spectra were tested and the optimized concentration ratio of Yb(3+) to Er(3+) ions was found to be 3:0.5 with a largest calculated emission cross-section (6.05×10(-21) cm(2)) corresponding to Er(3+):(4)I11/2?(4)I13/2 transition. When the concentration ratio of Yb(3+) to Er(3+) ions was 4:0.5, 1.5 ?m and 2.7 ?m emission decreased while up-conversion increased. The decreased 1.5 ?m and 2.7 ?m emission were induced by the saturation of Er(3+):(4)I13/2 level. In brief, the advantageous spectroscopic characteristics indicated that Yb(3+)/Er(3+) co-doped tungsten-tellurite glass may be a promising candidate for application of 2.7 ?m emission. PMID:23624041

Guo, Yanyan; Ma, Yaoyao; Huang, Feifei; Peng, Yapei; Zhang, Liyan; Zhang, Junjie

2013-07-01

370

Mid-infrared fluorescence, energy transfer process and rate equation analysis in Er3+ doped germanate glass.  

PubMed

Er(3+) doped Y2O3 and Nb2O5 modified germanate glasses with different Er(3+) concentrations were prepared. J-O intensity parameters were computed to estimate the structural changes due to the additions of Y2O3 and Nb2O5. The main mid-infrared spectroscopic features were investigated. To shed light on the observed mid-infrared radiative behavior, 975 nm and 1.53 ?m emission spectra along with their decay lifetimes were also discussed. Moreover, the energy transfer processes of (4)I11/2 and (4)I13/2 level were quantitatively analyzed. In view of the experimental lifetimes, the simplified rate equation was utilized to calculate the energy transfer upconversion processes of upper and lower laser level of 2.7 ?m emission. The theoretical calculations are in good agreement with the observed 2.7 ?m fluorescence phenomena. Finally, the stimulated emission and gain cross sections were calculated and the results indicate that Er(3+) doped germanate glasses have great potential for mid-infrared application. PMID:25317654

Wei, Tao; Tian, Ying; Chen, Fangze; Cai, Muzhi; Zhang, Junjie; Jing, Xufeng; Wang, Fengchao; Zhang, Qinyuan; Xu, Shiqing

2014-01-01

371

TiO2-doped phosphate glass microcarriers: A stable bioactive substrate for expansion of adherent mammalian cells  

PubMed Central

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

Guedes, Joana C; Park, Jeong-Hui; Lakhkar, Nilay J; Kim, Hae-Won; Knowles, Jonathan C

2013-01-01

372

Undoped and Eu3+ doped In2O3 quantum-dots in transparent glass-ceramics.  

PubMed

Nano-structured glass-ceramics comprising In2O3 nanocrystals (quantum dots) in a silica glassy matrix have been synthesized for the first time to our knowledge, by thermal treatment of sol-gel precursor glasses with different concentrations of In2O3. Undoped and Eu(3+)-doped samples have been obtained and characterized. By means of X-ray Diffraction and Transmission Electron Microscopy analysis, the precipitation of In2O3 cubic crystalline nanoparticles was confirmed. The mean radii of these nanocrystals, from 1 to 4 nm, are comparable to the exciton Bohr radius, corresponding to wide band-gap semiconductor quantum-dots. Under interband UV excitation of the nanocrystals, a broad visible emission is observed in the undoped samples. Meanwhile, the Eu(3+)-doped samples only show emission from these ions which are efficiently excited by energy transfer from the In2O3, nanocrystals. Selective excitation of the Eu3+ ions allow us to discern those remaining in the silica glassy matrix from the ones located in the interface SiO2-In2O3. PMID:19928158

del-Castillo, J; Yanes, A C; Méndez-Ramos, J; Rodríguez, V D

2009-08-01

373

Optical properties of Bi-doped Mg-Al silicate glasses and fibers  

NASA Astrophysics Data System (ADS)

The paper compares the absorption and emission properties of bulk glasses prepared by sintered in an iridium crucible and optical fibers fabricated by the powder-in-tube method. Both the bulk glasses and fibers were prepared from identical mixtures. The emission properties of the bulk samples and fibers were similar, while the "gray losses" in the fibers were an order of magnitude lower than those in the crucible melted glasses.

Velmiskin, Vladimir V.; Galagan, Boris I.; Denker, Boris I.; Sverchkov, Sergey E.; Semjonov, Sergey L.; Firstov, Sergey V.; Shulman, Ilya L.; Bufetov, Igor A.; Dianov, Evgeniy M.

2012-04-01

374

Spectral analysis of Er3+-, Er3+\\/Yb3+- and Er3+\\/Tm3+\\/Yb3+-doped TeO2 ZnO WO3 TiO2 Na2O glasses  

Microsoft Academic Search

In this paper, we present the spectroscopic properties of Er3+-, Er3+\\/Yb3+- and Er3+\\/Tm3+\\/Yb3+-doped novel tellurite glasses. From the measured absorption spectra, Judd-Ofelt (JO) intensity parameters (Omega2, Omega4 and Omega6) have been evaluated for the Er3+-doped glass. With 980 nm excitation three strong upconversion emission bands centered at 505, 520 and 630 nm were observed for both Er3+- and Er3+\\/Yb3+-codoped glasses

G. Lakshminarayana; Jianrong Qiu; M. G. Brik; G. A. Kumar; I. V. Kityk

2008-01-01

375

Electron, hole and exciton self-trapping in germanium doped silica glass from DFT calculations with self-interactions correction  

SciTech Connect

We performed density functional theory (DFT) calculations of electron, hole and exciton self-trapping in germanium doped silica glass to understand the refractive index change in these glasses induced by UV irradiation. The local structure relaxation and excess electron density distribution upon trapping of the above species were calculated. The results show that both trapped exciton and electron are highly localized on germanium ion and, to some extent, on its oxygen neighbors. Exciton self-trapping is found to lead to the formation of Ge E’ center and non-bridging hole center. Electron trapping changes the GeO4 tetrahedron structure into trigonal bi-pyramid with the majority of the excess electron density located along the equatorial line. Self-trapped hole is localized on bridging oxygen ions that are not coordinated to germanium atoms and leads to elongation of the Si-O bonds and change of the Si-O-Si bond angles. We did comparative study of standard DFT vs. DFT with a hybrid PBE0 exchange and correlation functional. The results show that the two methods give qualitatively similar relaxed structure and charge distribution for the electron and exciton trapping in germanium doped silica glass; however, only using the PBE0 functional reproduces the hole self-trapping. This research is supported by the Divisions of Chemical Science, Office of Basic Energy Sciences, US Department of Energy. This research was performed in part using the Molecular Science Computing Facility in the William R. Wiley Environmental Molecular Sciences Laboratory (EMSL) at the Pacific Northwest National Laboratory (PNNL). The EMSL is funded by DOE’s Office of Biological and Environmental Research. The pacific Northwest National Laboratory is operated by Battelle for the US Department of Energy.

Du, Jincheng; Corrales, Louis R.; Tsemekhman, Kiril L.; Bylaska, Eric J.

2007-02-01

376

Effect of Sm-, Gd-co-doping on structural modifications in aluminoborosilicate glasses under -irradiation  

E-print Network

. Introduction The modern concept of radioactive waste management suggests the confinement of radioactive wastes as surrogates for the actinides during the development of actinide-containing radioactive waste glasses [4 wastes have been vitrified with the use of, for example, aluminophosphate glasses (in Russia

Paris-Sud XI, Université de

377

Effect of silver-doped phosphate-based glasses on bacterial biofilm growth.  

PubMed

Silver-containing phosphate-based glasses were found to reduce the growth of Pseudomonas aeruginosa and Staphylococcus aureus biofilms, which are leading causes of nosocomial infections. The rates of glass degradation (1.27 to 1.41 microg.mm(-2).h(-1)) and the corresponding silver release were found to account for the variation in biofilm growth inhibitory effect. PMID:18567679

Valappil, Sabeel P; Knowles, Jonathan C; Wilson, Michael

2008-08-01

378

Development and characterisation of silver-doped bioactive glass-coated sutures for tissue engineering and wound healing applications.  

PubMed

A novel silver-doped bioactive glass powder (AgBG) was used to coat resorbable Vicryl (polyglactin 910) and non-resorbable Mersilk surgical sutures, thereby imparting bioactive, antimicrobial and bactericidal properties to the sutures. Stable and homogeneous coatings on the surface of the sutures were achieved using an optimised aqueous slurry-dipping technique. Dynamic mechanical analysis (DMA) was used to investigate the viscoelastic parameters of storage modulus and tandelta and thermal transitions of the as-received and composite (coated) sutures. The results generally showed that the bioactive glass coating did not affect the dynamic mechanical and thermal properties of the sutures. The in vitro bioactivity of the sutures was tested by immersion in simulated body fluid (SBF). After only 3 days of immersion in SBF, bonelike hydroxyapatite formed on the coated suture surfaces, indicating their enhanced bioactive behaviour. Resorbable sutures with bioactive coatings as fabricated here, in conjunction with 3-D textile technology, may provide attractive materials for producing 3-D scaffolds with controlled porosities for tissue engineering applications. The bactericidal properties imparted by the Ag-containing glass coating open also new opportunities for use of the composite sutures in wound healing and body wall repair. PMID:14643606

Blaker, J J; Nazhat, S N; Boccaccini, A R

2004-01-01

379

Use of microgravity to improve the efficiency and power output of Nd-doped laser glasses  

NASA Technical Reports Server (NTRS)

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.

Ray, Chandra S.

1992-01-01

380

Structure and optical properties of Dy3+/Tm3+ co-doped oxyfluoride glass ceramics containing ?-NaGdF4 nanocrystals  

NASA Astrophysics Data System (ADS)

Dy3+/Tm3+ co-doped oxyfluoride glass ceramics containing hexagonal ?-NaGdF4 nanocrystals were prepared by the melt-quenching method and subsequent heat-treatment procedure. During the crystallization process, the structural evolution of glass network was systematically investigated using XRD, TEM and FTIR spectra. Experimental results provided new evidences that a silica-enriched layer around the precipitated fluoride nanocrystals was formed during the crystallization process. Strong white light emission was obtained in the oxyfluoride glass ceramics by modifying the relative concentration ratio of Tm3+ and Dy3+ ions.

Sun, Xiao; Zhao, Shilong; Fei, Yong; Huang, Lihui; Xu, Shiqing

2014-12-01

381

Optical and thermal properties of P 2O 5–Na 2O–CaO–Al 2O 3:CoO glasses doped with transition metals  

Microsoft Academic Search

The aim of this paper is to report the optical and thermal properties of V2O5 and CuO doped P2O5–Na2O–CaO–Al2O3:CoO glasses so as to investigate their possible use in solar collection applications. The optical absorption spectra of the glasses at room temperature were in the spectral range of 200–1100nm. The optical band gaps of the glass samples were determined for direct

S. Cetinkaya Colak; E. Aral

2011-01-01

382

Bioactive Copper-Doped Glass Scaffolds Can Stimulate Endothelial Cells in Co-Culture in Combination with Mesenchymal Stem Cells  

PubMed Central

Bioactive glass (BG) scaffolds are being investigated for bone tissue engineering applications because of their osteoconductive and angiogenic nature. However, to increase the in vivo performance of the scaffold, including enhancing the angiogenetic growth into the scaffolds, some researchers use different modifications of the scaffold including addition of inorganic ionic components to the basic BG composition. In this study, we investigated the in vitro biocompatibility and bioactivity of Cu2+-doped BG derived scaffolds in either BMSC (bone-marrow derived mesenchymal stem cells)-only culture or co-culture of BMSC and human dermal microvascular endothelial cells (HDMEC). In BMSC-only culture, cells were seeded either directly on the scaffolds (3D or direct culture) or were exposed to ionic dissolution products of the BG scaffolds, kept in permeable cell culture inserts (2D or indirect culture). Though we did not observe any direct osteoinduction of BMSCs by alkaline phosphatase (ALP) assay or by PCR, there was increased vascular endothelial growth factor (VEGF) expression, observed by PCR and ELISA assays. Additionally, the scaffolds showed no toxicity to BMSCs and there were healthy live cells found throughout the scaffold. To analyze further the reasons behind the increased VEGF expression and to exploit the benefits of the finding, we used the indirect method with HDMECs in culture plastic and Cu2+-doped BG scaffolds with or without BMSCs in cell culture inserts. There was clear observation of increased endothelial markers by both FACS analysis and acetylated LDL (acLDL) uptake assay. Only in presence of Cu2+-doped BG scaffolds with BMSCs, a high VEGF secretion was demonstrated by ELISA; and typical tubular structures were observed in culture plastics. We conclude that Cu2+-doped BG scaffolds release Cu2+, which in turn act on BMSCs to secrete VEGF. This result is of significance for the application of BG scaffolds in bone tissue engineering approaches. PMID:25470000

Rath, Subha N.; Brandl, Andreas; Hiller, Daniel; Hoppe, Alexander; Gbureck, Uwe; Horch, Raymund E.; Boccaccini, Aldo R.; Kneser, Ulrich

2014-01-01

383

FTIR spectroscopy of borate crystals  

NASA Astrophysics Data System (ADS)

Infrared absorption spectroscopy has been used to study the vibrational modes in various borate crystals, the electronic transitions of Nd3+ ions in NYAB, and the stretching vibration of hydroxyl ions in CLBO crystals.

Kovacs, Laszlo; Beregi, E.; Polgar, K.; Peter, A.

1999-03-01

384

Low-temperature specific heat of rare-earth-doped silicate glasses D. A. van de Straat, J. Baak, and H. B. Brom  

E-print Network

the sample is permanently linked to a heat sink. Averaged temperature profiles are obtained by periodic between sample holder and heat sink. The calculated heat capacity was corrected for the contributionsLow-temperature specific heat of rare-earth-doped silicate glasses D. A. van de Straat, J. Baak

Schmidt, Thomas

385

Cr-doped scandium borate laser  

DOEpatents

A broadly wavelength-tunable laser is provided which comprises as the laser medium a single crystal of MBO.sub.3 :Cr.sup.3+, where M is selected from the group of Sc, In and Lu. The laser may be operated over a broad temperature range from cryogenic temperatures to elevated temperatures. Emission is in a spectral range from red to infrared, and the laser is useful in the fields of defense, communications, isotope separation, photochemistry, etc.

Chai, Bruce H. (Bridgewater, NJ); Lai, Shui T. (Florham Park, NJ); Long, Margaret N. (Landing, NJ)

1989-01-01

386

Optical characterization of Eu3+ and Tb3+ ions doped cadmium lithium alumino fluoro boro tellurite glasses.  

PubMed

This article reports on the development and spectral results of Eu(3+) and Tb(3+) ions doped cadmium lithium alumino fluoro boro tellurite (CLiAFBT) glasses in the following composition. 40TeO2-30B2O3-10CdO-10Li2O-10AlF3 (Hostglass) (40-x)TeO2-30B2O3-10CdO-10Li2O-10AlF3-xEu2O3 (40-x)TeO2-30B2O3-10CdO-10Li2O-10AlF3-xTb4O7 where x=0.25, 0.50, 0.75, 1.0, 1.25 mol%. Glass amorphous nature and thermal properties have been studied using the XRD and DSC profiles. From the emission spectra of Eu(3+):glasses, five emission transitions have been observed at 578 nm, 592 nm, 612 nm, 653 nm, 701 nm and are assigned to the transitions (5)D(0)?(7)F(0), (7)F(1,)(7)F(2), (7)F(3) and (7)F(4), respectively, with ?(exci)=392 nm ((7)F(0)?(5)L(6)). In case of Tb(3+):glasses, four emission transitions ((5)D(4)?(7)F(6,)(7)F(5), (7)F(4) and (7)F(3)) are observed at 488 nm, 543 nm, 584 nm and 614 nm, respectively, with ?(exci)=376 nm. Decay curves and energy level diagrams have been plotted to evaluate the life times and to analyze the emission mechanism. PMID:21397553

Raju, K Vemasevana; Sailaja, S; Raju, C Nageswara; Reddy, B Sudhakar

2011-06-01

387

Intense 2.7 ?m and broadband 2.0 ?m emission from diode-pumped Er3+/Tm3+/Ho3+-doped fluorophosphate glass  

NASA Astrophysics Data System (ADS)

This Letter reports intense emission at 2.7?m and broadband emission at 2.0?m from Er3+/Tm3+/Ho3+-doped fluorophosphate glass. The fluorescence characteristics and energy transfer upon excitation of a conventional 980nm laser diode are investigated. Based on the fluorescence spectra and lifetime measurement, the effect of Tm3+ and Ho3+ ions on intense 2.7?m emission in fluorophosphate glass is demonstrated. It is also found that the effective bandwidth of 2.0?m emission due to Tm3+ and Ho3+ ions can reach as high as 196nm. These results indicate that the advantageous spectroscopic characteristics of Er3+/Tm3+/Ho3+ triply doped fluorophosphate glass together with the outstanding thermal properties may become an attractive host for the mid-IR solid state lasers.

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

2011-08-01

388

Continuous laser-excited photothermal spectrometry of CdSxSe1-x doped glasses.  

PubMed

Photothermal lens measurements and finite element modeling are used to examine the physical changes taking place in optical filter glasses. Colored glass and neutral density filters are found to have a strong positive temperature-dependent refractive index change. The overall positive refractive index change is thought to be a consequence of complex counteracting factors: stress-induced birefringence, polarizability, structural network, and temperature-dependent carrier density changes in the CdSxSe1-x microcrystals that produce optical properties of these glasses. Finite element analysis (FEA) modeling is used to examine the temperature profiles and the goodness of the semi-infinite thermal diffusion solution normally used for thermal lens experiments. The results of FEA were used to optimize experimental parameters and calculate values of dn/dT for the glass by comparison with standard liquid samples. PMID:18198031

Dada, Oluwatosin O; Jorgensen, Matthew R; Bialkowski, Stephen E

2007-12-01

389

Sm2 + -doped silicate glasses prepared by a sol-gel process  

NASA Astrophysics Data System (ADS)

Silicate glasses, Al2O3?9SiO2, were successfully prepared to incorporate Sm2+ ions using a sol-gel process. The glasses synthesized through hydrolysis of Si(OC2H5)4, Al(OC4H9)3, and SmCl3?6H2O were heated in air, followed by heating in the presence of hydrogen, in which samarium ions were reduced from the trivalent to divalent state. Glasses incorporated with Sm2+ were colorless, transparent, and showed an intense emission with peaks at 683, 700, and 725 nm due to 5D0?7F0,1,2 transitions, respectively, of the Sm2+ ions. Irradiating the glasses with an Ar laser lowered the intensities of emission from Sm2+ ions and did not promote the formation of Sm3+ ions.

Nogami, M.; Abe, Y.

1994-09-01

390

Single-mode tapered waveguide laser in Er-doped glass with multimode-diode pumping  

NASA Astrophysics Data System (ADS)

We report on a demonstration of a planar waveguide laser configuration for single-mode operation around 1550 nm using cost-effective multimode diode pumping. The laser was fabricated by Ag film ion exchange in a hybrid phosphate glass which has active and passive regions monolithically integrated in a single glass chip. Power of 54 mW at 1538 nm was measured from the single-mode output waveguide.

Madasamy, Pratheepan; Honkanen, S.; Geraghty, D. F.; Peyghambarian, N.

2003-03-01

391

Effect of growth temperature on the properties of Nb-doped ZnO thin films grown on glass substrates  

NASA Astrophysics Data System (ADS)

Nb-doped ZnO (NZO) films were prepared on glass substrates at various deposition temperatures by using the radio-frequency magnetron sputtering method. All the NZO films showed a significant dependence on the growth temperature. The optimum growth temperature, which was determined from the figure of merit, for depositing high-quality NZO films was found to be 300 °C; the NZO thin film formed at this temperature showed a highly-preferential c-axis orientation with a thickness of 1040 nm, a grain size of 65 nm, a bandgap energy of 3.26 eV, an average optical transmittance of 87.9%, and an electrical resistivity of 6.6 × 10-3 ?·cm. These results indicate that the growth temperature plays an important role in the fabrication of NZO films and devices.

Cho, Shinho

2014-03-01

392

Absolute quantum cutting efficiency of Tb{sup 3+}-Yb{sup 3+} co-doped glass  

SciTech Connect

The absolute quantum cutting efficiency of Tb{sup 3+}-Yb{sup 3+} co-doped glass was quantitatively measured by an integrating sphere detection system, which is independent of the excitation power. As the Yb{sup 3+} concentration increases, the near infrared quantum efficiency exhibited an exponential growth with an upper limit of 13.5%, but the visible light efficiency was reduced rapidly. As a result, the total quantum efficiency monotonically decreases rather than increases as theory predicted. In fact, the absolute quantum efficiency was far less than the theoretical value due to the low radiative efficiency of Tb{sup 3+} (<61%) and significant cross-relaxation nonradiative loss between Yb{sup 3+} ions.

Duan, Qianqian [Condensed Matter Science and Technology Institute, Harbin Institute of Technology, Harbin 150001 (China); Qin, Feng; Zhang, Zhiguo, E-mail: zhangzhiguo@hit.edu.cn [Condensed Matter Science and Technology Institute, Harbin Institute of Technology, Harbin 150001 (China); Laboratory of Sono- and Photo-theranostic Technologies, Harbin Institute of Technology, Harbin 150001 (China); Zhao, Hua, E-mail: zhaoh@hit.edu.cn [School of Materials Science and Engineering, Harbin Institute of Technology, Harbin 150001 (China); Cao, Wenwu, E-mail: dzk@psu.edu [Condensed Matter Science and Technology Institute, Harbin Institute of Technology, Harbin 150001 (China); Laboratory of Sono- and Photo-theranostic Technologies, Harbin Institute of Technology, Harbin 150001 (China); Materials Research Institute, The Pennsylvania State University, Pennsylvania 16802 (United States)

2013-12-07

393

Thermo-Optical Tuning of Whispering Gallery Modes in Er:Yb Doped Glass Microspheres to Arbitrary Probe Wavelengths  

E-print Network

We present experimental results on an all-optical, thermally-assisted technique for broad range tuning of microsphere cavity resonance modes to arbitrary probe wavelengths. An Er:Yb co-doped phosphate glass (Schott IOG-2) microsphere is pumped at 978 nm via the supporting stem and the heat generated by absorption of the pump light expands the cavity and changes the refractive index. This is a robust tuning method that decouples the pump from the probe and allows fine tuning of the microsphere's whispering gallery modes. Pump/probe experiments were performed to demonstrate thermo-optical tuning to specific probe wavelengths, including the 5S1/2 F = 3 to 5P3/2 F' = 4 laser cooling transition of 85Rb. This is of particular interest for cavity QED-type experiments, while the broad tuning range achievable is useful for integrated photonic devices, including sensors and modulators.

Watkins, Amy; Chormaic, Síle Nic

2012-01-01

394

Enhanced luminescence of Tb{sup 3+}/Eu{sup 3+} doped tellurium oxide glass containing silver nanostructures  

SciTech Connect

We report on energy transfer studies in terbium (Tb{sup 3+})--europium (Eu{sup 3+}) doped TeO{sub 2}-ZnO-Na{sub 2}O-PbO glass containing silver nanostructures. The samples excitation was made using ultraviolet radiation at 355 nm. Luminescence spectra were recorded from approx =480 to approx =700 nm. Enhanced Eu{sup 3+} luminescence at approx =590 nm (transition {sup 5}D{sub 0}-{sup 7}F{sub 1}) and approx =614 nm (transition {sup 5}D{sub 0}-{sup 7}F{sub 2}) are observed. The large luminescence enhancement was obtained due to the simultaneous contribution of the Tb{sup 3+}-Eu{sup 3+} energy transfer and the contribution of the intensified local field on the Eu{sup 3+} ions located near silver nanostructures.

Kassab, Luciana R. P. [Laboratorio de Vidros e Datacao, Faculdade de Tecnologia de Sao Paulo (FATEC-SP), CEETEPS/UNESP, 01124-060 Sao Paulo, Sao Paulo (Brazil); Almeida, Ricardo de; Silva, Davinson M. da; Assumpcao, Thiago A. A. de [Departamento de Engenharia de Sistemas Eletronicos, Escola Politecnica da USP, 0550-900 Sao Paulo, Sao Paulo (Brazil); Araujo, Cid B. de [Departamento de Fisica, Universidade Federal de Pernambuco, 50670-901 Recife, Pernambuco (Brazil)

2009-05-15

395

Measurement of quantum yield of up-conversion Luminescence in Er(3+)-doped nano-glass-ceramics.  

PubMed

A measurement of quantum yield of up-conversion luminescence has been done for the Er(3+)-doped transparent oxyfluoride glass-ceramics 32(SiO,)9(AlO1.5)31.5(CdF2)18.5(PbF2)5.5(ZnF2): 3.5(ErF3) mol%, where most of Er3+ dopants partition in 8 nm diameter nano-crystals Er10Pb25F65. The yield was found by newly proposed method using the pump power dependence of the resonant luminescence. The result of the measurement points out that a theoretical maximum of 50% may be reached for the up-conversion luminescence yield in this material. This high yield is shown to be due to low phonon energy and short inter-dopant distances in the nano-crystals. PMID:19435083

Rodríguez, V D; Tikhomirov, V K; Méndez-Ramos, J; del-Castillo, J; Görller-Walrand, C

2009-03-01

396

Correlation of XANES features with the scintillation efficiencies of Ce doped alkaline earth lithium silicate glasses  

SciTech Connect

Cerium-activated, lithium-silicate glasses are widely used as thermal neutron detectors because of their versatility, robustness and low cost. The glasses convert the energy of the neutrons to visible light pulses that may be counted. This process, scintillation, is generally thought to be composed of three steps: ionization, energy transfer, and luminescence. If defects are present, they can trap the excitations, altering the scintillation output. These features have been discussed previously. The presence of magnesium in these glasses increases scintillation efficiency, but as previously observed the effect drops by a factor greater than 2.5 with substitution through the series of alkaline earths. Here, cerium activated glasses of composition 20Li{sub 2}O{center_dot}15MO{center_dot}64.4SiO{sub 2}{center_dot}0.6Ce{sub 3}O{sub 3} (where m is Mg, Ca, Sr, or Ba) exhibit scintillation efficiencies that vary by more than a factor of 2.5 with the alkaline earth. Previous work has suggested a correlation between the microstructure of these glasses and scintillation efficiency. Measurements of the Ce L{sub III} x-ray absorption edge in the Mg, Ca and Sr glasses display a feature near the absorption edge that is suggestive of the presence of Ce{sup 4+}. The area of this peak is, in fact, correlated with the scintillation efficiency of the glass. The amount of Ce{sup 4+} indicated by the intensity of this feature is, however, too high to be a permanent population. The authors suspect that the feature is a transient phenomenon related to creation of Ce{sup 4+} and trapped electrons due to photoionization by the x-ray beam.

Blanchard, D.L.; Sunberg, D.S.; Craig, R.A.; Bliss, M. [Pacific Northwest Lab., Richland, WA (United States); Weber, M.J. [Lawrence Livermore National Lab., CA (United States)

1994-11-01

397

Investigation of spectroscopic properties, structure and luminescence spectra of Sm3+ doped zinc bismuth silicate glasses  

NASA Astrophysics Data System (ADS)

The glasses with compositions 20ZnO·(79.5 - x)Bi2O3·xSiO2·0.5Sm2O3 (10 ? x ? 50, mol%) have been synthesized using normal melt-quench technique. Optical absorption and fluorescence spectra of the glasses were recorded at ambient temperature. Judd-Ofelt (J-O) theory has been successfully applied to characterize the absorption and luminescence spectra of these glasses. From the measured intensities of absorption bands of these glasses, the Judd-Ofelt parameters, ?? (? = 2, 4, 6) have been evaluated. The variation of ?2 with Bi2O3 content has been attributed to changes in the asymmetry of the ligand field at the rare earth (RE) ion site (due to structural change) and to changes in RE-O covalency, whereas the variation of ?6 is found to be strongly dependent on nephlauxetic effect. The shift of the hypersensitive band shows that the covalency of the RE-O decreases with decrease in Bi2O3 content in the host glass. Also, using J-O theory various radiative properties like spontaneous emission probability (Arad), radiative life time (?r), fluorescence branching ratio (?r) and stimulated emission cross-section (?) for various emission bands of these glasses in the visible spectral region have been determined. A close correlation is observed between the Bi2O3 content and the spectroscopic, radiative and structural properties of the prepared glasses. The values of radiative properties indicated that 4G5/2 ? 6H7/2 and 4G5/2 ? 6H9/2 transitions responsible for orange luminescence might be used in the development of materials for LED's and other optical devices in the visible region.

Pal, I.; Agarwal, A.; Sanghi, S.; Aggarwal, M. P.

2013-01-01

398

Investigation of spectroscopic properties, structure and luminescence spectra of Sm3+ doped zinc bismuth silicate glasses.  

PubMed

The glasses with compositions 20ZnO·(79.5-x)Bi2O3·xSiO2·0.5Sm2O3 (10?x?50, mol%) have been synthesized using normal melt-quench technique. Optical absorption and fluorescence spectra of the glasses were recorded at ambient temperature. Judd-Ofelt (J-O) theory has been successfully applied to characterize the absorption and luminescence spectra of these glasses. From the measured intensities of absorption bands of these glasses, the Judd-Ofelt parameters, ?? (?=2, 4, 6) have been evaluated. The variation of ?2 with Bi2O3 content has been attributed to changes in the asymmetry of the ligand field at the rare earth (RE) ion site (due to structural change) and to changes in RE-O covalency, whereas the variation of ?6 is found to be strongly dependent on nephlauxetic effect. The shift of the hypersensitive band shows that the covalency of the RE-O decreases with decrease in Bi2O3 content in the host glass. Also, using J-O theory various radiative properties like spontaneous emission probability (Arad), radiative life time (?r), fluorescence branching ratio (?r) and stimulated emission cross-section (?) for various emission bands of these glasses in the visible spectral region have been determined. A close correlation is observed between the Bi2O3 content and the spectroscopic, radiative and structural properties of the prepared glasses. The values of radiative properties indicated that 4G5/2?6H7/2 and 4G5/2?6H9/2 transitions responsible for orange luminescence might be used in the development of materials for LED's and other optical devices in the visible region. PMID:23099163

Pal, I; Agarwal, A; Sanghi, S; Aggarwal, M P

2013-01-15

399

Enhanced photoluminescence and structure of Dy3+-doped SrBi2Ta2O9-containing transparent glass-ceramics  

NASA Astrophysics Data System (ADS)

Trivalent dysprosium (Dy3+)-doped precursor glass in the K2O-SiO2-SrO-Bi2O3-Ta2O5 (KSSBT) system have been prepared by melt-quench technique and strontium bismuth tantalate, SrBi2Ta2O9 (SBT) glass-ceramics has been synthesized by a controlled crystallization process of the precursor glass. With progression of heat-treatment it is observed that Dy3+:glass exhibit a blue emission at 486 nm (4F9/2 ? 6H15/2) and also a bright fluorescent yellow emission at 576 nm (4F9/2 ? 6H13/2) have been observed with ?ex = 455 nm (6H15/2 ? 4I15/2). These spectra reveal that the Dy3+ ions are gradually entering into the SBT nanocrystals of the glass-ceramics. The photoluminescence characteristics originating from Dy3+-doping in nanocrystalline SBT reveals the dependence of the luminescent intensity on heat-treatment time. Their structural properties have also been evaluated by FTIR spectroscopic and microstructural studies. Such luminescent glass-ceramics are expected to find potential applications such as solid-state yellow lasers and optical display systems.

Tarafder, Anal; Molla, Atiar Rahaman; Karmakar, Basudeb

2013-06-01

400

Microstructure, mechanical and bio-corrosion properties of Mn-doped Mg-Zn-Ca bulk metallic glass composites.  

PubMed

The effects of Mn substitution for Mg on the microstructure, mechanical properties, and corrosion behavior of Mg69-xZn27Ca4Mnx (x=0, 0.5 and 1at.%) alloys were investigated using X-ray diffraction, compressive tests, electrochemical treatments, and immersion tests, respectively. Microstructural observations showed that the Mg69Zn27Ca4 alloy was mainly amorphous. The addition of Mn decreases the glass-forming ability, which results in a decreased strength from 545 MPa to 364 MPa. However, this strength is still suitable for implant application. Polarization and immersion tests in the simulated body fluid at 37 °C revealed that the Mn-doped Mg-Zn-Ca alloys have significantly higher corrosion resistance than traditional ZK60 and pure Mg alloys. Cytotoxicity test showed that cell viabilities of osteoblasts cultured with Mn-doped Mg-Zn-Ca alloys extracts were higher than that of pure Mg. Mg68.5Zn27Ca4Mn0.5 exhibits the highest bio-corrosion resistance, biocompatibility and has desirable mechanical properties, which could suggest to be used as biomedical materials in the future. PMID:23910284

Wang, Jingfeng; Huang, Song; Li, Yang; Wei, Yiyun; Xi, Xingfeng; Cai, Kaiyong

2013-10-01

401

A 2 ?m continuous wave and passively Q-switched fiber laser in thulium-doped germanate glass fibers  

NASA Astrophysics Data System (ADS)

In this study, we designed and fabricated a Tm3+-doped germanate glass fiber by using a rod-in-tube technique. The fiber has a core diameter of ~13.5??m with a cladding of 125??m. The Tm3+ doping concentration reached ~13?500?ppm, and the propagation loss of the fiber was less than 0.03?dB?cm???1 at 1310?nm. Pumping with a 1590 nm fiber laser constructed in-house, a 44.7?mW continuous-wave fiber laser at 1940?nm was achieved in a 22?cm-long germanate fiber, with a slope efficiency of 26%. The passively Q-switched pulse output was first demonstrated by using a carbon nanotube saturable absorber in the germanate fiber. The germanate fiber laser generates approximately 1.5??s pulses with a maximum pulse energy of 110?nJ, and the repetition rate varies from 15 to 84?kHz, depending on pump power.

Fan, Xiaokang; Kuan, Peiwen; Li, Kefeng; Zhang, Lei; Li, Wentao; Hu, Lili

2014-08-01

402

Near-infrared broadband luminescence and energy transfer in Bi-Tm-Er co-doped lanthanum aluminosilicate glasses  

NASA Astrophysics Data System (ADS)

The Bi-Tm-Er co-doped SiO2-Al2O3-La2O3 (SAL) glasses, which exhibited a broadband near-infrared (NIR) emission, were investigated by the optical absorption and photoluminescence spectra. A super broadband NIR emission extending from 0.95 to 1.6 ?m with a full-width at half-maximum (FWHM) of 430 nm which covered the whole O, E, S, C and L bands, was observed in Bi-Tm-Er co-doped samples under 808 nm excitation, as a result of the overlap of the Bi-related emission band (centered at 1270 nm) and the emission from Tm3+3H4?3F4 transition (1450 nm) as well as Er3+4I13/2?4I15/2 transition (1545 nm). In addition, a super broadband emission with amplitude relatively flat from 0.95 to 2.1 ?m has been observed. The possible energy transfer between Bi-related centers, Tm3+ ions and Er3+ ions was proposed.

Minh Hau, Tran; Wang, Rongfei; Yu, Xue; Zhou, Dacheng; Song, Zhiguo; Yang, Zhengwen; He, Xijia; Qiu, Jianbei

2012-09-01

403

In vitro biocompatibility and mechanical performance of titanium doped high calcium oxide metaphosphate-based glasses.  

PubMed

This study challenged to produce phosphate-based glasses (PBG) for the treatment of osseous defects. The glasses contained, among other components, 40?mol% CaO and 1-5?mol% TiO(2). The mechanical performance and in vitro biocompatibility using both human osteosarcoma and primary osteoblasts were carried out. Incorporation of TiO(2) into PBG had no significant effect on strength and modulus. These glasses encouraged attachment and maintained high viability of osteosarcoma cells similar to the positive control surface. Cells grown directly (on glasses) or indirectly (in the presence of glass extracts) showed similar proliferation pattern to the positive control cells with no significant effect of TiO(2) detected. Increasing TiO(2) content, however, has a profound effect on cytoskeleton organization and spreading and maturation of primary osteoblasts. It is believed that TiO(2) might have acted as a chemical cue-modulating cells response, and hence the substrates supported maturation/mineralization of the primary osteoblasts. PMID:21350644

Abou Neel, Ensanya A; Chrzanowski, Wojciech; Georgiou, George; Dalby, Matthew J; Knowles, Jonathan C

2010-01-01

404

Spectroscopic properties of Er{sup 3+} doped lead telluroborate glasses for 1.5 ?m broadband amplifiers  

SciTech Connect

Er{sup 3+} doped lead telluroborate glasses (xEPTB) with the composition 25B{sub 2}O{sub 3}-(25-x)TeO{sub 2}-25PbO-10Bi{sub 2}O{sub 3}-15CdO-xEr{sub 2}O{sub 3} (where x=0.1, 0.5, 1 and 2 wt%) have been prepared and characterised using NIR luminescence and decay measurements for 1.5 ?m broadband amplifier applications. Judd-Ofelt intensity parameters have been derived to predict radiative properties of the {sup 4}I{sub 13/2}?{sup 4}I{sub 15/2} emission transition. The larger values of stimulated emission cross-section (?P), FWHM, gain bandwidth (?G), radiative lifetime (?{sup cal}), quantum efficiency (?) of the 1EPTB glass suggest their potential use in broadband amplifiers. The effect of RE ion concentration and OH{sup ?} content on the lifetime of {sup 4}I{sub 13/2}?{sup 4}I{sub 15/2} transition and the energy transfer mechanism of Er{sup 3+} ions have also been discussed and reported in the present study.

Vijayakumar, R., E-mail: mari-ram2000@yahoo.com; Arunkumar, S., E-mail: mari-ram2000@yahoo.com; Vijayakumar, M., E-mail: mari-ram2000@yahoo.com; Marimuthu, K., E-mail: mari-ram2000@yahoo.com [Department of Physics, Gandhigram Rural Institute ? Deemed University, Gandhigram - 624302 (India)

2014-04-24

405

Al2O3 doped apatite-wollastonite containing glass ceramic provokes osteogenic differentiation of marrow stromal stem cells.  

PubMed

Fresh marrow cells were obtained from femora of Fischer rats and cultured in a medium containing 15% fetal calf serum (FCS) until confluence. After trypsinization, cells were subcultured at a cell density of 100 x 10(3)/35-mm well in the presence of FCS, beta-glycerophosphate, and ascorbic acid phosphate on four different culture substrata. The period of subculture was 2 weeks; the substrata used were the culture dish, apatite-wollastonite containing glass ceramic (AW), hydroxyapatite coated AW (HA/AW), and Al2O3 doped AW (Al/AW). The HA coating was attained by the incubation of AW in simulated physiological solution. The glass matrix of AW and HA/AW contained MgO, CaO, P2O5, and SiO2; Al/AW contained Al2O3 in addition to these components. The subculture on Al/AW substratum showed many alkaline phosphatase (ALP) positive nodules and the highest ALP activity. On a Northern blot analysis the housekeeping gene of beta-actin mRNA was evenly detected from the cells cultured on all substrata; however, bone-specific osteocalcin mRNA was only detected from the cells on Al/AW. These results indicate that Al/AW provokes the osteoblastic differentiation of marrow stromal stem cells. PMID:10397941

Ohgushi, H; Yoshikawa, T; Nakajima, H; Tamai, S; Dohi, Y; Okunaga, K

1999-03-15

406

Luminescence quenching and recovering in photo-thermo-refractive silver-ion doped glasses  

NASA Astrophysics Data System (ADS)

A spectroscopic investigation of luminescent centers transformation in photo-thermo-refractive glass by using ultraviolet (UV) nanosecond laser pulses with radiation wavelength 355 nm was performed. Initially the glass was irradiated by UV lamp and thermal-treated that causes a neutral silver molecular clusters luminescence in a visible spectral region. After the laser irradiation a luminescence quenching was observed in the irradiated region. The thermal treatment below glass transition temperature restores the luminescence of silver molecular clusters with complex spatial distribution of luminescence intensity inside the irradiated region. UV lamp irradiation achieves the same result without any inhomogeneity. The observed effects are caused by photoionization and reduction of subnanosized silver molecular clusters with the participation of cerium and antimony ions.

Klyukin, D. A.; Sidorov, A. I.; Ignatiev, A. I.; Nikonorov, N. V.

2014-12-01

407

GaInNAs semiconductor disk lasers as pump sources for Tm3+ (,Ho3+ )-doped glass, crystal and fibre lasers  

NASA Astrophysics Data System (ADS)

We report the first use of a Semiconductor Disk Laser (SDL) as a pump source for ~2?m-emitting Tm3+ (,Ho3+)-doped dielectric lasers. The ~1213nm GaInNAs/GaAs SDL produces >1W of CW output power, a maximum power transfer net slope efficiency of 18.5%, and a full width half maximum wavelength tuning range of ~24nm. Free-running operation of a Tm3+-doped tellurite glass laser under 1213nm SDL pumping generated up to 60mW output power with 22.4% slope efficiency. Wavelength tunable output is also obtained from 1845 to 2043nm. Improved performance with output powers of ~200mW and a slope efficiency of ~35% are achieved by replacing the Tm3+-doped glass with a Tm3+-doped KYW active medium. Emission of a Tm3+,Ho3+-codoped tellurite glass laser is also reported with maximum output power of ~12mW and a ~7% slope efficiency. Finally, preliminary investigations of 1213nm-pumping of a Tm3+,Ho3+-codoped silica fibre laser lead to 36mW output power with ~19.3% slope efficiency.

Vetter, Sharon L.; McKnight, L. J.; Calvez, Stephane; Dawson, Martin D.; Fusari, F.; Lagatsky, Alexander A.; Sibbett, Wilson; Brown, Christian T. A.; Korpijärvi, Ville-Markus; Guina, Mircea D.; Richards, B.; Jose, G.; Jha, Animesh

2009-02-01

408

Thermal, structural and magnetic properties of some zinc phosphate glasses doped with manganese ions  

Microsoft Academic Search

(MnO)x·(P2O5)40·(ZnO)60?x glasses containing different concentrations of MnO ranging from 0 to 20mol% were prepared by the melt-quenching technique. The samples had a fixed P2O5 content of 40mol% and the MnO:ZnO ratio was varied. The thermal, structural and magnetic properties of these glasses were investigated by means of differential thermal analysis (DTA), electron paramagnetic resonance (EPR) and magnetic susceptibility measurements. Compositional

Petru Pascuta; Maria Bosca; Gheorghe Borodi; Eugen Culea

2011-01-01

409

Photo-induced mass transfer in metal nanocluster doped glasses under continuous wave laser irradiation  

SciTech Connect

Mass transfer accompanying continuous wave optical recording in glasses with embedded silver nanoclusters has been studied using optical microscopy, STEM and AFM. Recording was carried out by two crossed laser beams (514 nm), which created a periodic intensity distribution on the illuminated surface of the glass-silver composites. The quality of the recorded gratings was found to be independent of the light polarization. It was determined that laser irradiation induces two mass transfer processes: diffusion coalescence of nanoclusters and redistribution of silver between illuminated and nonilluminated interference lines. The temperature profile under the illuminated surface has been calculated, as well as the kinetics of the mass redistribution.

Kaganovskii, Yu.; Rosenbluh, M. [Jack and Pearl Resnick Institute for Advanced Technology, Department of Physics, Bar-Ilan University, Ramat-Gan 52900 (Israel)

2011-04-15

410

Studies of oxide glass structure using laser ionization time of flight mass spectrometry  

NASA Astrophysics Data System (ADS)

We report on our work on determining the structure of oxide glasses using laser ionization time of flight mass spectrometry. This technique is especially suitable for investigation of the intermediate-range order in glasses, where it can measure the presence and relative abundance of mesounits composed of 7-20 or more atoms. After introducing the experimental aspects and caveats of this new spectroscopy, we discuss the application of the instrument to a variety of heavy-metal oxide glass families. We separate our networks into those that have superstructural networks and those that show highly fragmented ones, including our studies of lead and bismuth borates, lead silicates, lead vanadates, and bismuth gallates. We also analyse our spectra for evidence of mixing in lead borosilicates, and to clarify the sharing of cations in sodium-doped lead borosilicates.

Affatigato, Mario; Feller, Steve; Schue, Allison K.; Blair, Sarah; Stentz, Dale; Smith, Garret B.; Liss, Dan; Kelley, Matt J.; Goater, Cole; Leelesagar, Raghuvir

2003-08-01

411

Electrical, dielectric and spectroscopic studies on MnO doped LiI-AgI-B2O3 glasses  

NASA Astrophysics Data System (ADS)

LiI-AgI-B2O3 glasses doped with different concentrations of MnO (ranging from 0 to 0.8 mol%) were prepared. Electrical and dielectric properties have been studied over a wide frequency range of 10-2 - 106 Hz and in the temperature range from 173 to 523 K. The valence states of manganese ions and their coordination in the glass network have been investigated using optical absorption, luminescence, and ESR spectroscopy. The analysis of the spectroscopic results has indicated that the manganese ions exist in both Mn2+ and Mn3+ states and occupy octahedral and tetrahedral positions. With increasing MnO concentration there is a gradual increase in the tetrahedral occupancy of Mn2+ ions at the expense of octahedral occupancy in the glass network. The results of dc conductivity have indicated that when T > ?D/2, the small polaron hopping model is appropriate and the conduction is adiabatic in the nature. Further, the analysis of experimental data indicates that there is a mixed, ionic and electronic, conduction. It has been observed that the electrical conductivity decreases as the concentration of MnO increases suggesting the electronic conduction controlled by polaron hopping between manganese ions. In the low temperature region, up to 250 K, the ac conductivity is nearly temperature independent and varies linearly with frequency, which can be explained by the quantum mechanical tunneling (QMT) model. The dielectric properties have been analyzed in the framework of complex dielectric permittivity and complex electrical modulus formalisms. The evolution of the complex permittivity as a function of frequency and temperature has been investigated.

Moguš-Milankovi?, A.; Pavi?, L.; Srilatha, K.; Srinivasa Rao, Ch.; Srikumar, T.; Gandhi, Y.; Veeraiah, N.

2012-01-01

412

Ho3+/Er3+ doped fluoride glass sensitized by Ce3+ pumped by 1550 nm LD for efficient 2.0 ?m laser applications.  

PubMed

We present a detailed characterization of enhanced 2.0 ?m emission and energy transfer processes by codoping Ce3+ in ZBYA: Ho3+/Er3+ glasses under 1550 nm excitation. The measured absorption and emission spectra show that Er3+ ions are efficiently excited by pumping and energy transfer from Er3+: 4I13/2 to Ho3+: 5I7 level. The 2.0 ?m emission from the Ho3+: 5I7?5I8 transition is enhanced by codoping Ce3+ (< 0.5 mol %) ions in the Ho3+/Er3+ doped glasses. However, excess Ce3+ ions in the glass network negatively affect the mid-infrared emission. The upconversion luminescence is dominated by Er3+ (667 nm) red emission in the Ho3+/Er3+ doped sample, which is suppressed after introducing Ce3+ ions. The red emission is abnormally dominated by the Ho3+ (650 nm) emission when the ratio of the three ions (Ho3+/Er3+: Ce3+) is 1:1:0.5. These results indicate that Ce3+ ions can enhance Ho3+: 2.0 ?m emission by suppressing the upconversion processes. The Ho3+/Er3+/Ce3+ triply-doped ZBYA glass is a promising material for 2.0 ?m fiber laser applications. PMID:25321293

Huang, Feifei; Cheng, Jimeng; Liu, Xueqiang; Hu, Lili; Chen, Danping

2014-08-25

413

High-efficiency ytterbium-free erbium-doped all-glass double cladding silicate glass fiber for resonantly-pumped fiber lasers.  

PubMed

A highly efficient ytterbium-free erbium-doped silicate glass fiber has been developed for high-power fiber laser applications at an eye-safe wavelength near 1.55 ?m. Our preliminary experiments show that high laser efficiency can be obtained from a relatively short length of the gain fiber when resonantly pumped at 1535 nm in both core- and cladding-pumping configurations. With a core-pumping configuration as high as 75%, optical-to-optical efficiency and 4 W output power were obtained at 1560 nm from a 1 m long gain fiber. When using a cladding-pumping configuration, approximately 13 W output power with 67.7% slope efficiency was demonstrated from a piece of 2 m long fiber. The lengths of silicate-based gain fiber are much shorter than their silica-based counterparts used in other experiments, which is significantly important for high-power narrow-band and/or pulsed laser applications. PMID:24514181

Qiang, Zexuan; Geng, Jihong; Luo, Tao; Zhang, Jun; Jiang, Shibin

2014-02-01

414

Silicon, iron and titanium doped calcium phosphate-based glass reinforced biodegradable polyester composites as bone analogous materials  

NASA Astrophysics Data System (ADS)

Bone defects resulting from disease or traumatic injury is a major health care problem worldwide. Tissue engineering offers an alternative approach to repair and regenerate bone through the use of a cell-scaffold construct. The scaffold should be biodegradable, biocompatible, porous with an open pore structure, and should be able to withstand the applied forces. Phosphate-based glasses (PGs) may be used as reinforcing agents in degradable composites since their degradation can be predicted and controlled through their chemistry. This doctoral dissertation describes the development and evaluation of PGs reinforced biodegradable polyesters for intended applications in bone augmentation and regeneration. This research was divided into three main objectives: 1) Investigating the composition dependent properties of novel PG formulations by doping a sodium-free calcium phosphate-based glass with SiO2, Fe2O3, and TiO2. Accordingly, (50P2 O5-40CaO- xSiO2-(10-x)Fe2O3, where x = 10, 5 and 0 mol.%) and (50P2O5-40CaO-xSiO 2-(10-x)TiO2 where x = 10, 7, 5, 3 and 0 mol.%) formulations were developed and characterised. SiO2 incorporation led to increased solubility, ion release, pH reduction, as well as hydrophilicity, surface energy, and surface polarity. In contrast, doping with Fe2O 3 or TiO2 resulted in more durable glasses, and improved cell attachment and viability. It was hypothesised that the presence of SiO 2 in the TiO2-doped formulations could up-regulate the ionic release from the PG leading to higher alkaline phosphatase activity of MC3T3-E1 cells. 2) Incorporating Si, Fe, and Ti doped PGs as fillers, either as particulates (PGPs) or fibres (PGFs), into biodegradable polyesters (polycaprolactone (PCL) and semi-crystalline and amorphous poly(lactic acid) (PLA and PDLLA)) with the aim of developing degradable bone analogous composites. It was found that PG composition and geometry dictated the weight loss, ionic release, and mechanical properties of the composites. It was also hypothesised that a potential reaction between Si and the ester bond led to the formation of carboxylate by-products resulting in a lower molecular weight polymer, thus affecting the mechanical properties of the composites. Cytocompatibility assessment with MC3T3-E1 pre-osteoblasts showed that these composites were cytocompatible, and cell alignment along the PGFs was observed possibly due to their favourable ionic release properties. 3) Investigating the solid-state foaming using carbon dioxide (CO 2) of PDLLA-PGP composites with up to 30 vol.% filler content. While PDLLA foams resulted in 92% porosity, the porosity of the composites ranged between 79 and 91% which decreased with PGP content. In addition, a reduction in pore size was observed with increasing PGP content; however, the pore size maintained its range of 200-500 ?m in all composite foams, suitable for bone tissue engineering applications. The percentage of open pores increased significantly with PGP content (up to 78% at 30 vol.% PGP). Compressive strength and modulus of PDLLA-PGP foams showed up to approximately 3-fold increase at 30 vol.% PGP content compared to neat PDLLA foams.

Shah Mohammadi, Maziar

415

Zero Field NMR Study on a Spin Glass: Iron-Doped 2HYDROGEN-NIOBIUM Diselenide.  

NASA Astrophysics Data System (ADS)

We have used spin echoes to study the ('93)Nb NQR in 2H-NbSe(,2)Fe(,x). We measured (intensity) x (temperature), and T(,1P) (spin-lattice relaxation parameter) and T(,2) (spin-spin relaxation time) as a function of temperature. Our data reveal dramatic difference between non-spin glass samples (x = 0, 0.25%, 1% and 5%) and spin glass samples (x = 8%, 10% and 12%). Defining the spin glass transition temperature T(,g) by the cusp of the susceptibility versus temperature curve, we find well-defined minima at T = T(,g) in (intensity) x (temperature), T(,1P) and T(,2) as a function of temperature. Deduction of a correlation time of Fe spins from T(,1P) and T(,2) is complicated by the intensity changes which imply that one observes different groups of nuclei at different temperatures. We propose a two -correlation-time model, which utilizes the anisotropy of the exchange interaction, to overcome this difficulty. All of our NQR results and the model calculation of the correlation times of Fe spins are best described by the phase transition picture of spin glasses.

Chen, Men-Chee

1982-03-01

416

EPR and optical absorption spectral studies of Cu 2+ ions doped in alkali lead tetraborate glasses  

NASA Astrophysics Data System (ADS)

Electron paramagnetic resonance and optical absorption spectra of Cu 2+ ions in 90R 2B 4O 7+(10- x) PbO + xCuO (where R=Li, Na and K; 0.25 ? x ? 1.5 mol% of CuO) glasses have been studied. EPR spectra of all glasses show resonance peaks characteristic of Cu 2+ ions. From the observed EPR spectra, the spin-Hamiltonian parameters have been evaluated. The values of spin-Hamiltonian parameters indicate that Cu 2+ ions in alkali lead tetraborate glasses have octahedral coordination with a strong tetragonal distortion. The number of spins participating in resonance is measured as a function of temperature and the activation energy is calculated. The paramagnetic susceptibility is also calculated from the EPR data at various temperatures. From the plot of temperature versus 1/ ?, the Curie constant and the Curie temperature values have been evaluated. The optical absorption spectra of all the glass samples show two bands. One broad band at low-energy side is assigned to 2B 1g? 2B 2g transition of Cu 2+ ion and the intense band at high-energy side is assigned to charge transfer band. By correlating EPR and optical absorption data, the molecular orbital coefficients have been evaluated.

Lakshmana Rao, J.; Sivaramaiah, G.; Gopal, N. O.

2004-06-01

417

Enhanced near-infrared response of CdS/CdTe solar cell using Tm3+ and Yb3+ co-doped upconverting glass phosphors  

NASA Astrophysics Data System (ADS)

Tm3+ and Yb3+ co-doped upconverting (UC) glass phosphors were used to converting near-infrared to visible light and input to a CdS/CdTe solar cell, therefore to enhance solar cell's response in the near-infrared of the sub-bandgap region. Current-voltage measurements were performed on the solar cell with a UC glass phosphor. A short-circuit photocurrent enhancement of 31 ?A was obtained using a Tm3+and Yb3+ co-doped glass UC phosphor, illuminated by a 980 nm diode laser at 100 mW. This photocurrent response corresponds to external quantum efficiency (EQE) of 0.04 % at 980 nm. For full collection of the UC light in 4? solid angle, the EQE value is expected to reach 1.6 %. The photo-current observed was proportional to the effective UC light intensity from glass UC phosphor. A non-linear relation between the output photo-current and the incident power of the infrared light was observed, similar to the relation between UC intensity and the incident power. UC efficiency of the glass phosphor was calculated using EQE values at both UC wavelengths and at 980 nm.

Pan, Z.; Whyte, D.; Morgan, S. H.; Li, J.; Alaswad, A.; Beach, J. D.; Ohno, T. R.; Wolden, C. A.

2014-10-01

418

Transparent Ni2+-Doped MgO-Al2O3-SiO2 Glass Ceramics with Broadband Infrared Luminescence  

NASA Astrophysics Data System (ADS)

We report on transparent Ni2+-doped MgO-Al2O3-SiO2 glass ceramics with broadband infrared luminescence. Ni2+-doped MgO-Al2O3-SiO2 glass is prepared by using the conventional method. After heat treatment at high temperature, MgAl2O4 crystallites are precipitated, and their average size is about 4.3 nm. No luminescence is detected in the as-prepared glass sample, while broadband infrared luminescence centred at around 1315 nm with full width at half maximum (FWHM) of about 300 nm is observed from the glass ceramics. The observed infrared emission could be attributed to the 3T2g(3F)?3A2g(3F) transition of octahedral Ni2+ ions in the MgAl2O4 crystallites of the transparent glass ceramics. The product of the fluorescence lifetime and the stimulated emission cross section is about 1.6×10-24 s cm2.

Wu, Bo-Tao; Zhou, Shi-Feng; Qiu, Jian-Rong; Peng, Ming-Ying; Yang, Lü-Yun; Jiang, Xiong-Wei; Zhu, Cong-Shan

2006-10-01

419

[Upconversion and mid-infrared fluorescence properties of Ho3+/Yb3+ co-doped 50SiO2-50PbF2 glass ceramic].  

PubMed

In the present paper, the upconversion and mid-infrared fluorescence properties of Ho3+/Yb3+ co-doped 50SiO2- 50PbF2 glass ceramic (GC) were studied. The GC has the following composition (in mol%): 50SiO2-50PbF2-1YbF3-0. 5HoF3. The mixtures of about 10 g were placed in a corundum crucible and melted at 1000 degrees C for 15 min in a SiC electric furnace in air and then poured on a brass plate. The GCs were obtained just by heat treatment at 450 degrees C. The X-ray diffraction pattern of the GC indicates that very small size crystals were precipitated in the precursor glass by heat treatment. The GCs have as high transmittance as glasses. The GCs have higher absorption cross section and narrower absorption peaks compared to the corresponding glasses, indicating that fluoride is doped with Ho ions. The Judd-Ofelt intensity parameters were determined from the absorption spectrum and Judd-Ofelt theory. The omega2 value is 0.17 x 10(-20) cm2 lower than that of fluoride glass ZBLA (2.28 x 10(-20) cm2), because of Ho3+ doping in PbF2 microcrystal. The intense green upconversion light was observed in Ho3+/Yb3+ co-doped 50SiO2-50PbF2 GCs excited by 980 nm laser diode. A main emission band centered around 540 nm (green), and three week emission bands centered around 420 nm(violet), 480 nm (blue), and 650 nm (red) which correspond to the Ho3+ : ((5)F4-->(5)I8) ((5)G-->(5)I8), ((8)K3--(5)I8) and ((5)F5-->(5)I8) transitions, respectively, were simultaneously observed in GCs. Compared with the glass sample, GCs have significantly intension in the green and blue upconversion fluorescence, and not significant change in the red upconversion fluorescence. Those changes are because that Ho ion in GCs locates in lower phonon energy environment than in glasses. Lower phonon energy can make the nonradiative relaxation rate reduce, which improves the green light upconversion efficiency, at the same time reduces the population of the intermediate energy level ((5)I7) of the red light radiation. The 2.9 microm mid-infrared light was observed in GC sample, but not in glass precursor excited by 980 nm laser diode. PMID:25508713

Zhang, Xiao-guang; Ren, Guo-zhong; Yang, Huai

2014-08-01

420

[Upconversion and mid-infrared fluorescence properties of Ho3+/Yb3+ co-doped 50SiO2-50PbF2 glass ceramic].  

PubMed

In the present paper, the upconversion and mid-infrared fluorescence properties of Ho3+/Yb3+ co-doped 50SiO2- 50PbF2 glass ceramic (GC) were studied. The GC has the following composition (in mol%): 50SiO2-50PbF2-1YbF3-0. 5HoF3. The mixtures of about 10 g were placed in a corundum crucible and melted at 1000 degrees C for 15 min in a SiC electric furnace in air and then poured on a brass plate. The GCs were obtained just by heat treatment at 450 degrees C. The X-ray diffraction pattern of the GC indicates that very small size crystals were precipitated in the precursor glass by heat treatment. The GCs have as high transmittance as glasses. The GCs have higher absorption cross section and narrower absorption peaks compared to the corresponding glasses, indicating that fluoride is doped with Ho ions. The Judd-Ofelt intensity parameters were determined from the absorption spectrum and Judd-Ofelt theory. The omega2 value is 0.17 x 10(-20) cm2 lower than that of fluoride glass ZBLA (2.28 x 10(-20) cm2), because of Ho3+ doping in PbF2 microcrystal. The intense green upconversion light was observed in Ho3+/Yb3+ co-doped 50SiO2-50PbF2 GCs excited by 980 nm laser diode. A main emission band centered around 540 nm (green), and three week emission bands centered around 420 nm(violet), 480 nm (blue), and 650 nm (red) which correspond to the Ho3+ : ((5)F4-->(5)I8) ((5)G-->(5)I8), ((8)K3--(5)I8) and ((5)F5-->(5)I8) transitions, respectively, were simultaneously observed in GCs. Compared with the glass sample, GCs have significantly intension in the green and blue upconversion fluorescence, and not significant change in the red upconversion fluorescence. Those changes are because that Ho ion in GCs locates in lower phonon energy environment than in glasses. Lower phonon energy can make the nonradiative relaxation rate reduce, which improves the green light upconversion efficiency, at the same time reduces the population of the intermediate energy level ((5)I7) of the red light radiation. The 2.9 microm mid-infrared light was observed in GC sample, but not in glass precursor excited by 980 nm laser diode. PMID:25474934

Zhang, Xiao-guang; Ren, Guo-zhong; Yang, Huai

2014-08-01

421

Deposition, characterization, reflow and analysis of undoped and boron trioxide/phosphorus pentoxide-doped germanosilicate glass films  

NASA Astrophysics Data System (ADS)

Plasma Enhanced Chemical Vapor Deposition (PECVD) of undoped mixed GeO 2-SiO2 glass films in a horizontal tube reactor using germane, silane and oxygen has been studied. Doped films of the mixed GeO2-SiO 2 glass using diborane and phosphine have been studied as well. The glass films offer the potential for both trench etch-refill and interlevel dielectric applications. Film synthesis