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1

Devitfrification Properties Of Bismuth Borate Glasses Doped With Trivalent Ions  

SciTech Connect

Bismuth borate glasses and crystalline phases have outstanding luminescent and nonlinear optical properties; therefore there is lot of interest in their preparation and characterization. In this study we report the crystallization properties of bismuth borate glasses doped with trivalent ions. Glasses of the composition: xBi{sub 2}O{sub 3}-(100-x)B{sub 2}O{sub 3} (x = 20, 25, 30, 37.5, 40, 50, 60 and 66 mol %) and 40Bi{sub 2}O{sub 3}-1Tv{sub 2}O{sub 3}-59B{sub 2}O{sub 3}(where Tv = Al, Nd and Eu) were prepared by melt quench technique and devitrified by heat treatment above their glass transition temperatures for several hours. The crystalline phases produced were characterized by FTIR absorption spectroscopy, DTA and X-ray diffraction. Bi{sub 3}B{sub 5}O{sub 12} was found to be the predominant phase in all crystallized samples containing Bi{sub 2}O{sub 3} concentration of {<=}40 mol %, at higher Bi{sub 2}O{sub 3} concentration, we observed the formation of Bi{sub 4}B{sub 2}O{sub 9} phase. Glasses with Bi{sub 2}O{sub 3} concentration of {<=}37.5 mol % produced Bi{sub 2}B{sub 8}O{sub 15} phase on crystallization. The metastable BiBO{sub 3}-I phase was formed by short duration heat treatment (less than 5 hours) of the initial glass sample. Doping with rare earth ions like Eu{sup 3+} and Nd{sup 3+} promotes the formation of BiBO{sub 3}-II phase while Al{sup 3+} doping suppresses it.

Khanna, Atul [Department of Physics, Guru Nanak Dev University, Amritsar-143005, Punjab (India); Bajaj, Anu [Department of Applied Sciences, Adesh Institute of Engineering and Technology, Faridkot-151203, Punjab (India)

2010-12-01

2

Synthesis and structural studies of praseodymium doped silver borate glasses  

SciTech Connect

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

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

2013-02-05

3

Synthesis and structural studies of praseodymium doped silver borate glasses  

NASA Astrophysics Data System (ADS)

Praseodymium doped silver borate glasses with nominal composition xPr6O11-(25-x)Ag2O-75B2O3 (x=0, 1, 2, 3, 4, 5) were prepared by melt quench technique. XRD pattern shows that there is no sharp peak it confirms the amorphous nature of the present glasses. The glass transition temperature (Tg) of this glass system have been studied using the Matac MBS-8000 Digital Signal Processing and Conventional Thermal Analysis (DTA) method. The Tg of these glasses increases with increase in concentration of Pr6O11 except at 0.2 mol%, Tg value is lower. 11B MAS-NMR shows the presence of sharp peak around 0.306 ppm. Chemical shift of these glasses decreases with mol% of rare earth oxide. FTIR spectra recorded in the region of 400 to 4000 cm-1. This studies revealed that the progressive addition Ag2O and Pr6O11 leads to modification of B2O3 into BO4 groups. Raman measurements of these glasses support the proposed interpretations of the experimental results.

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

2013-02-01

4

Optical properties of Sm3+-doped cadmium bismuth borate glasses  

NASA Astrophysics Data System (ADS)

This article reports on the optical properties of cadmium bismuth borate (CdBiB) glasses doped with various concentrations of Sm3+ ions. FT-IR spectra of Sm3+:CdBiB glasses have been used to identify the functional groups present in the composition of the glasses. The emission spectra of Sm3+:CdBiB glasses have shown an intense reddish-orange emission at 600 nm (4G5/2 ? 6H7/2). From the absorption spectrum, the experimental oscillator strengths were determined and have been used to calculate the Judd-Ofelt (J-O) intensity parameters. By using the J-O intensity parameters, various radiative properties have been studied and computed for the various transitions of Sm3+:CdBiB glasses. Based on the values of stimulated emission cross section, radiative transition rate and the branching ratio of the emission transition 4G5/2 ? 6H7/2, it is suggested that 1.0 mol% of Sm3+:CdBiB glass is the promising luminescent material towards lasing applications. The nature of luminescence decay curves of 4G5/2 level with different concentrations of Sm3+:CdBiB glasses are also reported.

Sailaja, S.; Nageswara Raju, C.; Adinarayana Reddy, C.; Deva Prasad Raju, B.; Jho, Young-Dahl; Sudhakar Reddy, B.

2013-04-01

5

Structural and optical properties of niobium doped silver-lead-borate glasses  

NASA Astrophysics Data System (ADS)

Nb2O5 doped silver lead borate glasses with the chemical composition (29—x)PbO-1Ag2O-70B2O3-xNb2O5 (where x=0.1mol % and 0.5 mol %) have prepared by conventional melt quenching method. FTIR and UV absorption technique have been used in order to obtain the information concerning network structure. As Nb2O5 concentration increased, the borate glass network is shown to change three coordinated to four coordinated boron system. SEM technique confines glassy nature of the prepared samples. The calculated optical band gap increases with increase Nb2O5 concentration.

Sathish, M.; Eraiah, B.

2013-06-01

6

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

7

Structural studies of lead lithium borate glasses doped with silver oxide.  

PubMed

Silver oxide doped lead lithium borate (LLB) glasses have been prepared and characterized. Structural and composition characterization were accessed by XRD, FTIR, Raman, SEM and EDS. Results from FTIR and Raman spectra indicate that Ag(2)O acts as a network modifier even at small quantities by converting three coordinated to four coordinated boron atoms. Other physical properties, such as density, molar volume and optical basicity are also evaluated. Furthermore, they are also affected by the silver oxide composition. PMID:22088558

Coelho, João; Freire, Cristina; Hussain, N Sooraj

2012-02-01

8

Preparation and properties of silver-borate glasses doped with praseodymium oxide  

NASA Astrophysics Data System (ADS)

Silver-borate glasses doped with Praseodymium oxide having composition xPr6O11-(25-x)Ag2O-75B2O3 (x = 0,1,2,3,4,5mol%) were prepared by conventional melt quenching method. The density, molar volume, and optical energy band gap of these glasses have been measured. Optical absorption spectra of these glasses were recorded in the range 300-1000 nm at room temperature. The optical energy band gap obtained in the present work is 1.9531eV to 2.4166 eV.

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

2013-06-01

9

Synthesis and characterization of holmium oxide doped cadmium lead borate glasses  

NASA Astrophysics Data System (ADS)

Holmium doped cadmium lead borate glasses were prepared from melting in appropriate proportions of a mixture of CdO, PbO2, H3BO3 and (1-2 mol %) Ho2O3 in the temperature range of 800-850 °C. The density of glass samples was measured using Archimedes Principle. The infrared spectra of the glasses in the range of 400-4000 cm-1 showed their structure systematically. No boroxol ring formation was observed in the structure of these glasses, but the conversion of 3-fold to 4-fold coordination of boron atoms in the structure of glasses was observed. The glass transition studies were done through differential scanning calorimetry. The optical analysis is done by using the Judd-Ofelt theory.

Alemi, A. A.; Sedghi, H.; Mirmohseni, A. R.; Golsanamlu, V.

10

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

PubMed

Spectroscopic investigations on different concentrations (0.1, 0.5, 1.0, 1.5 and 2.0mol%) of Pr(3+) and Nd(3+) doped strontium lithium bismuth borate glasses have been done. X-ray diffraction, SEM with EDS, absorption and luminescence spectra were recorded for all the glass matrices and analyzed. X-ray diffraction profiles and SEM images conformed amorphous nature of investigated glass samples. EDS spectra of host glass and Pr(3+)doped glass matrices gave information about the chemical composition of glass samples. From the absorption spectra of Pr(3+) and Nd(3+) ions, Judd-Ofelt (J-O) intensity parameters (?(?),?=2, 4 and 6) have been calculated and compared with other glass matrices. The emission characteristics such as radiative lifetimes (?(R)), measured and calculated branching ratios (?) and stimulated emission cross-sections (?(P)) have been obtained for the observed emission transitions of Pr(3+) and Nd(3+) ions in the above glass matrix for all the concentrations. From the emission spectra of Pr(3+) and Nd(3+) doped glass matrices, the effect of concentration on the quenching of intensity of (1)D(2)?(3)H(4) transition of Pr(3+) ion and (4)F(3/2)?(4)I(9/2), (4)I(11/2) and (4)I(13/2) transitions of Nd(3+) have been studied and discussed. PMID:22925972

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

2012-11-01

11

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

PubMed

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

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

2011-08-15

12

Elastic properties of silver borate glasses doped with praseodymium oxide  

NASA Astrophysics Data System (ADS)

A series of glasses xPr6O11-(35-x) Ag2O-65B2O3 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 Pr6O11 inside the glass network was discussed.

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

2014-04-01

13

Optical and structural properties of lithium sodium borate glasses doped Dy3+ ions  

NASA Astrophysics Data System (ADS)

Absorption and emission spectra of lithium sodium borate glass doped with different concentrations of Dy3+ have been reported. The concentration of Dy3+ was varied from 0.3 to 1.3 mol%. The amorphous nature of the prepared samples was confirmed by the X-ray Diffraction (XRD). Fourier transforms infrared (FTIR) spectra, and other significant physical properties (energy band gap, density, ion concentration, molar volume, Polaron radius and inter-nuclear distance) have been analyzed in the light of the different oxidation states of the co-dopant ions. The absorption spectrum showed nine peaks with hypersensitive transition corresponding to 6F11/2 + 6H9/2 at 1256 nm. As a result of 380 nm excitation wavelength, the luminescence spectra showed two characteristic bands at 479 nm and 587 nm. These absorption bands were attributed to 6P15/2 ? 6H15/2 and 6P15/2 ? 6H13/2 transitions of trivalent Dy3+ ions. The current study indicates that Dy doped lithium sodium borate glasses are attractive for solid-state laser applications.

Dawaud, Raghda Saeif Eddin Said; Hashim, Suhairul; Alajerami, Yasser Saleh Mustafa; Mhareb, M. H. A.; Tamchek, N.

2014-10-01

14

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

15

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.

16

Luminescence spectra and structure of Er3+ doped alkali borate and fluoroborate glasses  

NASA Astrophysics Data System (ADS)

Trivalent erbium (Er3+) ion doped alkali borate and fluoroborate glasses were prepared and their structural and spectroscopic properties have been studied through XRD, FTIR, optical absorption and luminescence spectral measurements. The FTIR spectral studies reveal the presence of BO3, BO4 structural units and the strong OH- bonds in the title glasses. The absorption spectra were used to determine the bonding parameters (?¯,?) of the prepared glasses. Judd—Ofelt intensity parameters (??, ?=2, 4 and 6) have been calculated from the optical absorption spectra and are used to predict the important radiative properties like radiative transition probability (A), stimulated emission cross-section (?PE) and branching ratios (?R) for the excited state transitions such as 2H9/2?4I15/2 and 4S3/2?4I15/2 of the Er3+ ions in the prepared glasses. Optical band gap energy (Eopt) values through direct, indirect allowed transitions and the Urbach energy (?E) values of the prepared Er3+ glasses have also been determined and compared with similar studies. The spectral characteristics of the Er3+ ions due to compositional changes have been examined and reported in the present work.

Arul Rayappan, I.; Marimuthu, K.

2013-11-01

17

Physical and optical properties of dysprosium ion doped strontium borate glasses  

NASA Astrophysics Data System (ADS)

The effect of dysprosium ion (Dy3+) on the optical absorption and band gap energy of strontium borate glass systems prepared by melt quenching technique have been reported. The results show that the broad absorption edge of doped glasses shifts back and forth as a function of Dy2O3 concentrations. The intensities of five prominent and two weak optical transitions change accordingly with Dy2O3 concentrations. The defect centres are induced with the presence of Dy3+ ions in glass samples. This attributes to the intra-configurational (f-f) transitions of Dy3+ ions in glass network. In addition, the decreasing trend of optical band gap energy and Urbach energy can be related to defect centres created by Dy3+ ions. The FTIR study reveals the presence of BO3, BO4 vibration groups and the bending of B-O-B units. The asymmetric stretching of BO3 and BO4 was apparent at higher Dy2O3 concentrations. More tetrahedral BO4 units were formed by increasing Dy2O3 concentrations. The dependency of Dy2O3 concentrations on the optical properties is further discussed with other important physical properties.

Lim, Tou Ying; Wagiran, H.; Hussin, R.; Hashim, S.; Saeed, M. A.

2014-10-01

18

Ho(3+) -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 (AR ), 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) I8 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) I8 , (5) S2 ((5) F4 )?(5) I8 and (5) F5 ?(5) I8 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. Copyright © 2014 John Wiley & Sons, Ltd. PMID:24519914

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

2014-11-01

19

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

20

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

21

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

22

Optical and photophysical investigation of Meso, Proto and Hematoporphyrin(IX)dimethylester doped hybrid borate glasses  

NASA Astrophysics Data System (ADS)

Hybrid borate glasses containing different concentrations (0.5-2.0 mg in 12 g of boric acid) of Mesoporphyrin(IX)dimethylester, Protoporphyrin(IX)dimethylester and Hematoporphyrin(IX)dimethylester were prepared by rapid melt quench technique at 230 °C. The hybrid glass samples were characterized by X-ray diffraction, optical absorption, steady state and time-resolved fluorescence emission. The optical absorption spectrum shows red-shift in Soret band along with change in Q-band pattern. The intensity of Q-band was found to increase with increase in the concentration of porphyrin in the glass. Steady state emission spectrum shows strong S 2?S 0 emission in the range 462-495 nm and blue shift in S 1?S 0 emission. Time-resolved fluorescence emission and fluorescence excitation spectra showed that different structures of porphyrins were exist in the glass samples. The variation in the spectral behaviour in the glass was correlated with those in solution medium and possible structures of porphyrin in borate glass were explored.

Venkatramaiah, N.; Soorya, V. C.; Venkatesan, R.

2011-02-01

23

Nonlinear optical properties of silver nanoparticles prepared in Ag doped borate glasses  

NASA Astrophysics Data System (ADS)

Nonlinear properties of Li2B4O7:Ag borate glasses with “Li2B4O7:Ag nanoparticles” interface region formed by thermal treatment in hydrogen atmosphere and in vacuum are investigated. From the results of plasmon absorption and normalized transmission measurements in Z-scan regime it was ascertained that “Li2B4O7:AgNPs” interface region changes the character of nonlinear refraction of Li2B4O7:Ag glass from negative to positive, and, due to plasmon resonance, increases significantly its nonlinear properties. In particular, the observed growth of nonlinear refractive index n2 is more than four orders of magnitude.

Adamiv, V. T.; Bolesta, I. M.; Burak, Ya. V.; Gamernyk, R. V.; Karbovnyk, I. D.; Kolych, I. I.; Kovalchuk, M. G.; Kushnir, O. O.; Periv, M. V.; Teslyuk, I. M.

2014-09-01

24

Role of oxygen on the optical properties of borate glass doped with ZnO  

SciTech Connect

Lithium tungsten borate glass (0.56-x)B{sub 2}O{sub 3}-0.4Li{sub 2}O-xZnO-0.04WO{sub 3} (0{<=}x{<=}0.1 mol%) is prepared by the melt quenching technique for photonic applications. Small relative values of ZnO are used to improve the glass optical dispersion and to probe as well the role of oxygen electronic polarizability on its optical characteristics. The spectroscopic properties of the glass are determined in a wide spectrum range (200-2500 nm) using a Fresnel-based spectrophotometric technique. Based on the Lorentz-Lorenz theory, as ZnO content increases on the expense of B{sub 2}O{sub 3} the glass molar polarizability increased due to an enhanced unshared oxide ion 2p electron density, which increases ionicity of the chemical bonds of glass. The role of oxide ion polarizability is explained in accordance with advanced measures and theories such as optical basicity, O 1s binding energy, the outer most cation binding energy in Yamashita-Kurosawa's interionic interaction parameter and Sun's average single bond strength. FT-IR measurements confirm an increase in bridging oxygen bonds, as a result of replacement of ZnO by B{sub 2}O{sub 3}, which increase the UV glass transmission window and transmittance. - Graphical abstract: O1s, Yamashita-Kurosawa's parameter and average single bond strength of charge overlapping between electronic shells are used to explain enhanced oxide ion 2p electron density, which increases refractive index of glasses. Highlights: > New borate glass for photonic application is prepared. > The dispersion property of the glass is effectively controlled using small amounts of ZnO. > ZnO is used to probe the glass structure and investigate the role of oxygen on the obtained optical properties of the glasses. > Modern theories are used to explain enhanced unshared oxide ion 2p electron density, which increases ionicity of chemical bonds of the glass.

Abdel-Baki, Manal [Glass Research Department, National Research Center, Dokki, 12311 Giza (Egypt); El-Diasty, Fouad, E-mail: fdiasty@yahoo.com [Physics Department, Faculty of Science, Ain Shams University, Abbasia Cairo 11566 (Egypt)

2011-10-15

25

Electrical, dielectric and optical properties of La2O3 doped lithium borate glasses  

NASA Astrophysics Data System (ADS)

Effect of La2O3 addition on electrical and optical properties of lithium borate glass has been studied in the present work. Glass system with general formula 27.5 Li2O-(72.5-X) B2O3-X La2O3 was prepared by normal melting process. Electrical properties were studied by impedance spectroscopy. Scaling behavior was introduced to study dynamical process. In order to study optical properties, absorption spectra were measured at room temperature. Direct and indirect optical band gap, Urbach energy and Fermi energy were calculated from absorption spectra using functionality of extinction coefficient from Fermi-Dirac distribution function. Optical parameter shows the dependence on physical properties i.e. density and molar volume. There is good correlation between electrical and optical properties.

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

2013-07-01

26

Spectroscopic properties and luminescence behaviour of europium doped lithium borate glasses  

NASA Astrophysics Data System (ADS)

Li2O-MO-B2O3 (MO=ZnO, CaO and CdO) glasses doped with europium are prepared by using the melt quenching technique to study their absorption and luminescence properties to understand their lasing potentialities. The XRD pattern of the glasses confirmed the amorphous nature and the IR spectra reveal the presence of BO3 and BO4 units in the glass network. Judd-Ofelt intensity parameters ?? (?=2, 4, 6) are evaluated from the intensities of various absorption bands of optical absorption spectra. The J-O parameters have been used to calculate transition probabilities (A), lifetime (?R), branching ratios (?R) and stimulated emission cross-section (?P) for the 5D0?7FJ (J=1-4) transitions of the Eu3+ ions. The decay from the 5D0 level of Eu3+ ions in these glasses has been measured and analysed. Branching ratios and stimulated emission cross-sections measured for all these glasses show that the 5D0?7F1 transition under investigation has the potential for laser applications. The high stimulated emission cross-section and branching ratios from the present glasses suggests their potential for infra red lasers. The study of the thermoluminescence is also carried out and the data suggests that the CdBEu glass is suitable for thermoluminescence emission output among the three Eu3+ doped glasses.

Anjaiah, J.; Laxmikanth, C.; Veeraiah, N.

2014-12-01

27

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

28

Optical and FTIR structural studies of CoO-doped sodium borate, sodium silicate and sodium phosphate glasses and effects of gamma irradiation-a comparative study  

NASA Astrophysics Data System (ADS)

Undoped and CoO-doped three binary glass systems, namely sodium borate, sodium silicate and sodium phosphate glasses were prepared by the melt annealing technique. Combined optical and FTIR spectral studies were carried out for the prepared samples before and after being subjected to a gamma dose of 8 Mrad (8 × 104 Gy). Optical spectra of the undoped samples before irradiation reveal strong UV absorption varying in depth with the type of glass and such strong UV spectra are related to the presence of unavoidable trace iron impurities within the raw materials used for the preparation of these three basic glasses. CoO-doped (0.25%) glasses show additional visible absorption spectra which are related to the existence of cobalt in the divalent state (Co)2+ ions which are present in two coordination states, namely the octahedral and tetrahedral forms. The broad visible band of Co2+ ions shows in some instances obvious splitting to three component peaks. Gamma irradiation on undoped glasses causes obvious induced UV-visible bands and their extension depends on the type of glass system. Irradiation of CoO-doped glasses causes an obvious increase of absorption within the visible region. Infrared absorption spectra of the undoped three basic glasses reveal IR vibrational bands which are characteristics to the three specific characteristic structural building units within the borate, silicate and phosphate glasses. The introduction of CoO with the doping level causes minor variations of the IR spectra because of the low doping content together with the presence of cobalt ions in structural modifying sites. Gamma irradiation is observed to cause limited changes within the intensities of some bands in the IR spectra which are attributed to changes in bond lengths and/or bond angles of the structural building units by the irradiation process.

Abdelghany, A. M.; ElBatal, F. H.; ElBatal, H. A.; EzzElDin, F. M.

2014-09-01

29

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

30

Crystallization of bismuth borate glasses.  

PubMed

Bismuth borate glasses with Bi(2)O(3) concentration of 20-66 mol% were prepared by melt quenching and devitrified by heat treatment above their glass transition temperatures. All glasses show a strong tendency towards crystallization on annealing that increases with Bi(2)O(3) concentration. The crystalline phases formed on devitrification were characterized by FTIR absorption spectroscopy and DSC measurements. Our studies reveal that phases produced in glasses are strongly determined by initial glass composition and the two most stable crystalline phases are: Bi(3)B(5)O(12) and Bi(4)B(2)O(9). The metastable BiBO(3) phase can also be formed by devitrification of glass with 50 mol% of Bi(2)O(3). This phase is, however, unstable and decomposes into Bi(3)B(5)O(12) and Bi(4)B(2)O(9) on prolonged heat treatment. PMID:21817270

Bajaj, Anu; Khanna, Atul

2009-01-21

31

Physical and electrical properties of copper oxide doped bismuth borate glasses  

NASA Astrophysics Data System (ADS)

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

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

2013-06-01

32

Structural and physical properties of vanadium doped copper bismuth borate glasses  

SciTech Connect

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

Dhiman, R. L. [P. G. Department of Applied Physics, S. D. College, Ambala Cantt.-133 001 (India); Kundu, Virender Singh [Department of Electronic Science, Kurukshetra University, Kurukshetra-136 119 (India); Arora, Susheel; Maan, A. S. [Department of Physics, Maharishi Dayanand University, Rohtak 124 001 (India)

2013-02-05

33

XRD and EPR structural investigation of some zinc borate glasses doped with iron ions  

NASA Astrophysics Data System (ADS)

Glasses in the system xFe2O3·(100-x) [45ZnO·55B2O3] (0?x?10 mol%) have been prepared by melting at 1200 °C and rapidly cooling at room temperature. The obtained samples were submitted to an additional thermal treatment at 570 °C for 12 h in order to relax the glass structure as well as to improve the local order. The as cast and heat treated samples were investigated using X-ray diffraction (XRD) and electron paramagnetic resonance (EPR) measurements. The XRD patterns of all the studied samples show their vitreous nature. Structural modifications occurring in the heat treated samples compared to the untreated ones have been pointed out. EPR spectra of untreated and heat treated samples revealed resonance absorptions centered at g?2.0, g?4.3 and g?6.4. The compositional variation of the line intensity and linewidth of the absorptions from g?4.3 and g?2.0 have been interpreted in terms of the variation in the concentration of the Fe3+ ions and the interaction between the iron ions. The EPR spectra of the untreated samples containing 5 mol% Fe2O3 have been studied at different temperatures (110-290 K). The line intensity of the resonance signals decreases with increase in temperature whereas the linewidth is found to be independent of temperature. It was also found that the temperature variation of reciprocal line intensity obeys the Boltzmann law.

Stefan, Razvan; Pascuta, Petru; Popa, Adriana; Raita, Oana; Indrea, Emil; Culea, Eugen

2012-02-01

34

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.

35

Optical Absorption and Structural Studies of Pr3+ Doped Cadmium Bismuth Borate Glasses in Visible and Near Infrared Regions  

NASA Astrophysics Data System (ADS)

Glasses having composition 20CdOxBi2O3(79.5-x)B2O30.5Pr6O11 with x varying from 15 to 35 mol% have been synthesized. Optical absorption and fluorescence spectra were measured at ambient temperature. A close correlation is observed between the Bi2O3 content and the spectroscopic properties such as Judd-Ofelt intensity parameters ?? = (? = 2, 4, 6), radiative and structural properties of prepared glasses doped with Pr3+ ion. 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 has been related to the variation in RE-O covalency. Following the luminescence spectra, various radiative properties like transition probability (Arad), radiative lifetime (?r), branching ratio (?r) and stimulated emission cross section (?) have been calculated. The branching ratio for 3P0 ? 3F2 transition of Pr3+ glass system arrive at 41 to 40%, respectively, and the predicted spontaneous radiative transition probability rates are high and varies from 14032 to 14864 s-1. In addition, the glass stability is improved in which the substitution of B2O3 for Bi2O3 strengthens the glass network structure. The bismuth based glass as a host for Pr3+ ion doped suggesting their suitability for laser applications.

Pal, Inder; Agarwal, Ashish; Sanghi, Sujata; Sanjay; Bhardwaj, Sunil

36

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

37

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

38

UNCORRECTEDPROOF 2 Optical properties of bismuth borate glasses  

E-print Network

UNCORRECTEDPROOF 2 Optical properties of bismuth borate glasses 3 Isabella-Ioana Oprea, Hartmut.70.Ce; 78.20.Ci 13 Keywords: Bismuth borate; Glass; Refractive index; Optical properties 14 1 environment, i.e., in glass. Combining 34 bismuth oxide with boric oxide thus allows to tune the 35 optical

Osnabrück, Universität

39

UNCORRECTED 2 Luminescence of erbium-doped bismuthborate glasses  

E-print Network

UNCORRECTED PROOF 2 Luminescence of erbium-doped bismuth­borate glasses 3 Isabella-Ioana Oprea ions in the binary glass system bismuth oxide (Bi2O3)­boric oxide (B2O3) are 9 measured.V. 17 PACS: 42.70.Ce; 78.55.Qr 18 Keywords: Erbium doping; Bismuth­borate glass; Luminescence 19 20 1

Osnabrück, Universität

40

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

41

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 2glass microfibers are safe and effective for soft tissue applications. © 2014 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 102A: 4491-4499, 2014. PMID:24677635

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

2014-12-01

42

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

43

Thickness dependent ion conductivity of lithium borate network glasses  

NASA Astrophysics Data System (ADS)

Lithium borate network glasses are possible candidates for separator membranes in all-solid-state batteries. Thin films of a Li2O-borate glass were produced by argon beam sputtering and their specific ionic conductivities were measured by impedance spectroscopy. The conductivity of as-sputtered films is about two orders of magnitude higher compared to the conductivity of bulk glasses produced from the melt. Furthermore, thin films with a thickness of 7-125nm reveal a remarkable finite size effect after annealing: with decreasing thickness the specific dc conductivity increases about three orders of magnitude.

Berkemeier, F.; Shoar Abouzari, M.; Schmitz, G.

2007-03-01

44

Ultrasonic Investigation on Nanocrystalline Barium Borate (BBO) Glass Ceramics  

Microsoft Academic Search

Barium Borate (BBO) glasses containing different compositions of BaO and B2O3 with BaF2, Cr2O3 and TiO2 have been prepared by normal melting and annealing technique. The prepared bulk BBO glasses have been subjected to heat?treatment. The heat?treated BBO glasses produce nanophase BBO crystals in its structure. The existence of nanophase structure of the BBO crystals have been studied through XRD

A. V. Gayathri Devi; V. Rajendran; K. Jeyasubramanian; N. Suresh Kumar

2006-01-01

45

Synthesis and studies on microhardness of alkali zinc borate glasses  

NASA Astrophysics Data System (ADS)

The mixed alkali effect on zinc borate glasses have been reported. The glass systems of nominal composition 10Zn+xLi2O+yNa2O+80B2O3 (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 (Li2O and Na2O) 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 (BO4/2)- into (BO3/2)-. The microhardness studies reveals the anisotropy nature of the material. It further confirms that the samples belong to hard glass category.

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

2014-04-01

46

Crystal nucleation in lithium borate glass  

NASA Technical Reports Server (NTRS)

Crystal nucleation measurements were made on three lithium borate compositions in the vicinity of Li2O-2Br2O3. All nucleation measurements were performed at 500 C. Certain aspects of the nucleation behavior indicated (tentatively) that it proceeded by a homogeneous mechanism. The steady state nucleation rate was observed to have the largest value when the Li2O concentration was slightly in excess of the diborate composition. The change in nucleation rate with composition is controlled by the variation of viscosity as well as the change in free energy with composition. The variation of nucleation rate is explained qualitatively in these terms.

Smith, Gary L.; Neilson, George F.; Weinberg, Michael C.

1988-01-01

47

Gamma ray interaction with lithium borate glasses containing WO3  

Microsoft Academic Search

Glasses from the system of undoped lithium diborate and WO3-doped were synthesized by the usual melting and annealing techniques. UV-visible absorption spectra of the prepared sample were measured before and after successive gamma irradiation. Undoped glass reveals strong UV absorption spectrum which is related to the presence of unavoidable trace iron impurity. The presence of tungsten ions in this glass

Fatma H ElBatal

48

Third order nonlinear optical properties of bismuth zinc borate glasses  

SciTech Connect

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

Shanmugavelu, B.; Ravi Kanth Kumar, V. V., E-mail: ravi.phy@pondiuni.edu.in [Department of Physics, Pondicherry University, Puducherry 605 014 (India); Kuladeep, R.; Narayana Rao, D. [School of Physics, University of Hyderabad, Hyderabad 500046, Andhra Pradesh (India)

2013-12-28

49

Third order nonlinear optical properties of bismuth zinc borate glasses  

NASA Astrophysics Data System (ADS)

Third order nonlinear optical characterization of bismuth zinc borate glasses are reported here using different laser pulse durations. Bismuth zinc borate glasses with compositions xBi2O3-30ZnO-(70-x) B2O3 (where x = 30, 35, 40, and 45 mol. %) have been prepared by melt quenching method. These glasses were characterized by Raman, UV-Vis absorption, and Z scan measurements. Raman and UV-Vis spectroscopic results indicate that non-bridging oxygens increase with increase of bismuth content in the glass. Nonlinear absorption and refraction behavior in the nanosecond (ns), picosecond (ps), and femtosecond (fs) time domains were studied in detail. Strong reverse saturable absorption due to dominant two-photon absorption (TPA) was observed with both ps and fs excitations. In the case of ns pulse excitations, TPA and free-carrier absorption processes contribute for the nonlinear absorption. Two-photon absorption coefficient (?) and the absorption cross section due to free carriers (?e) are estimated by theoretical fit of the open aperture Z-scan measurements and found to be dependent on the amount of bismuth oxide in the glass composition. In both ns and fs regimes the sign and magnitude of the third order nonlinearity are evaluated, and the optical limiting characteristics are also reported.

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

2013-12-01

50

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

51

Structure-property relations in lanthanide borate glasses  

NASA Technical Reports Server (NTRS)

Glass formation in the system Ln2O3-B2O3 (Ln = Nd, Sm) was studied. Glasses could be formed in the range from 0 to 28 mol pct rare-earth oxide (Ln2O3), but liquid immiscibility in these systems limits the range of homogeneous glasses to 0 to 1.5 and 25 to 28 mol pct Ln2O3. The infrared spectra indicate that the rare-earth-rich glasses are structurally similar to rare-earth metaborates (LnB3O6) which contain (B3O6)-infinity chains. The variation in density, transformation temperature, thermal expansion coefficient, and transformation-range viscosity of these glasses with the size of the rare-earth ion is discussed. Glasses near the metaborate composition have a transformation temperature of about 700 C, which is high for binary borate glasses. Glasses could not be formed in the systems Eu2O3-, Gd2O3-, Ho2O3-, and Er2O3-B2O3, even by quenching at 1300 C/s. The sudden lack of glass formation in the system Ln2O3-B2O3 with Ln(3+) ions smaller than Sm(3+) is explained on the basis of the size effect of the Ln(3+) ion on the stability of (B3O6)-infinity chains in these metaborates.

Chakraborty, I. N.; Day, D. E.; Lapp, J. C.; Shelby, J. E.

1985-01-01

52

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

53

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

54

Preparation and characterization of magnesium borate for special glass  

NASA Astrophysics Data System (ADS)

Magnesium borate with a variety of B2O3/MgO molar ratios, which can be applied for special glass, has been prepared through the reaction of light-burned magnesia with boric acid by a hydrothermal method. The effects of the B2O3/MgO molar ratio of raw materials, reaction time, temperature and liquid to solid ratio (ml g-1) on the synthetic product are investigated. The XRD and TG-DTG analyses indicate that the prepared magnesium borate is a mixture of magnesium hexaborate hydrate and ascharite. The results show that high B2O3/MgO molar ratios of raw materials and low reaction liquid-solid ratios favour the product with a high B2O3/MgO molar ratio and vice versa. There exists free MgO in the product when the reaction temperature is below 140 °C or the reaction time is not enough, because of the incomplete reaction of magnesium oxide with boric acid. The process of fractional crystallization for the magnesium borate mixture is also discussed.

Dou, Lishuang; Zhong, Jianchu; Wang, Hongzhi

2010-05-01

55

Luminescence, structural and dielectric properties of Sm3+ impurities in strontium lithium bismuth borate glasses  

NASA Astrophysics Data System (ADS)

In the present work, different concentrations of Sm3+doped strontium lithium bismuth borate glasses (SLBiB) have been prepared by melt quench technique and investigated their optical, structural and dielectric properties. The amorphous nature of the prepared glass samples was confirmed by X-ray diffraction and SEM analysis. The spectroscopic properties of these glasses were investigated by recording optical absorption, photoluminescence and decay curve analysis. Judd-Ofelt (J-O) theory has been applied for the f ? f transitions of Sm3+ ions to evaluate J-O intensity parameters, ?? (? = 2, 4 and 6). Using the J-O intensity parameters, radiative properties such as transition probabilities (AR), calculated branching ratios (?) and radiative lifetimes (?) are estimated. From the emission spectra, effective bandwidths (??eff) and stimulated emission cross-sections (?p) have been obtained for observed emission levels. From the emission spectra, a strong reddish-orange emission corresponding to the transition, 4G5/2 ? 6H7/2 was observed. The nature of decay curves of 4G5/2 level for different Sm3+concentrations in SLBiB glass has been analyzed. FTIR spectra were recorded to analyze the functional groups present in the glass matrix. From the dielectric properties, variation of dielectric constant, dielectric loss and ac conductivity of Sm3+ doped different glass samples with the variation of frequency was studied.

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

2012-12-01

56

Impact of Nd3+ ions on physical and optical properties of Lithium Magnesium Borate glass  

NASA Astrophysics Data System (ADS)

Enhancing the up-conversion efficiency of borate glass via optimized doping of rare earth ions is an ever-ending quest in lasing glass. Neodymium (Nd3+) doped Lithium Magnesium Borate (LMB) glasses are prepared using the melt-quenching method. X-ray diffraction (XRD), Fourier transformed infrared (FTIR), UV-Vis-NIR absorption and Photoluminescence (PL) spectroscopic characterizations are made to examine the influence of Nd3+ concentration on physical properties and optical properties. Nd3+ contents dependent density, molar volume, refractive index, ion concentration, Polaron radius, inter nuclear distance, field strength, energy band gap and oscillator strength are calculated. XRD patterns confirm the amorphous nature of all glasses and the FTIR spectra reveal the presence of BO3 and BO4 functional groups. UV-Vis-IR spectra exhibit ten prominent bands centered at 871, 799, 741, 677, 625, 580, 522, 468, 426, 349 nm corresponding to the transitions from the ground state to 4F3/2, (4F5/2 + 2H9/2), (4F7/2 + 4S3/2), 4F9/2, 2H11/2, (4G5/2 + 2G7/2), (2K13/2 + 4G7/2 + 4G9/2), (2G9/2 + 2D3/2 + 2P3/2), (2P1/2 + 2D5/2), (4D3/2 + 4D5/2) excited states, respectively. A hyper-sensitive transition related to (4G5/2 + 2G7/2) level is evidenced at 580 nm. The room temperature up-conversion emission spectra at 800 nm excitation displays three peaks centered at 660, 610 and 540 nm. Glass with 0.5 mol% of Nd3+ showing an emission enhancement by a factor to two is attributed to the energy transfer between Mg2+ and Nd3+ ions. Our results suggest that these glasses can be nominated for solid state lasers and other photonic devices.

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

2014-11-01

57

Mechanical property evaluation of porous 13-93 Bioactive Glass and GL1550 Borate Glass 3D scaffolds D. Li, A. Scully, and T. M. G. Chu  

E-print Network

Mechanical property evaluation of porous 13-93 Bioactive Glass and GL1550 Borate Glass 3D scaffolds in either mechanical or biologic properties. Borate bioactive-glass (BBG) is a promising material for scaffolds due to its higher solubility compared to traditional 13-93 bioactive glass. The main objective

Zhou, Yaoqi

58

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

59

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

60

Nuclear Magnetic Resonance Studies of the Structure of Sodium Borosilicate, Magnesium Borate, Lithium Borate, and Sodium Fluoroberyllate Glasses  

NASA Astrophysics Data System (ADS)

B('11), B('10), Be('9), and F('19) NMR techniques are employed to gain information about the short-range order in four different glass-forming systems. In sodium borosilicate glasses of high soda content, B('11) studies yield the relative fractions of boron atoms in various bonding arrangements. The data show that if enough Na(,2)O is added, four-coordinated borons are destroyed and borons with one or two non-bridging oxygens are created, but that both the beginning point and the rate of these processes depend strongly on the amount of silica present. These findings are shown to be quantitatively inconsistent with structural models previously suggested in the literature. Utilizing the concept of proportionate atomic sharing of the additional Na(,2)O, a new structural model is proposed for K < 8 (K = mol% SiO(,2)/mol% B(,2)O(,3)). X-ray diffraction and B('11) NMR techniques are employed to study phase relations in the magnesium borate system at the metaborate composition. The formation of compounds is found to be highly dependent on the sample preparation technique. Contrary to reports in the literature, no evidence is found for a metaborate compound. It is argued that magnesium oxide acts in part as a network former to account for an unexpectedly low fraction of four-coordinated boron atoms and for the lack of non-bridging oxygen atoms in magnesium borate glass. B('10) NMR studies are carried out on lithium borate glasses over the entire glass forming region of the system. Assuming the validity of the Krogh-Moe model, the relative abundances of the various structural groupings are inferred from the data by fitting computer-simulated lineshapes to the experimental spectra. Distributions in quadrupole parameters due to the random nature of the glass are also inferred. Be('9) and F('19) NMR studies are carried out on two samples of sodium fluoroberyllate glasses: one sample is nominally pure BeF(,2), and the other is 67 wt% BeF(,2), 33 wt% NaF. Unlike the case for the binary sample, the central transition of the Be('9) spectrum for the nominally pure sample exhibits an anomalous narrow line. It is argued that the anomalous response is due to clustered Be atoms in a non-stoichiometric sample. The quadrupole coupling constant found to be a factor-of-four larger in the binary sample; it is argued that this is strong evidence for the existence of five-coordinated Be atoms in sodium fluoroberyllate glasses.

dell, Warren James

61

Compositional dependence of ultraviolet fluorescence intensity of Ce 3+ in silicate, borate, and phosphate glasses  

Microsoft Academic Search

Fluorescence spectra of Ce3+ ions in silicate, borate, and phosphate glasses melted in Ar were measured. The relative fluorescence intensity of Ce3+ in the ultraviolet region increased in the order of R=Ba, Ca, Sr, and Mg in the 20Li2O–20RO–60SiO2 glass samples and with decreasing BaO content in the BaO–B2O3 glass samples, respectively. In contrast, the relative fluorescence intensity of Ce3+

T. Murata; M. Sato; H. Yoshida; K. Morinaga

2005-01-01

62

Evaluation of hydroxyapatite microspheres made from a borate glass to separate protein mixtures  

Microsoft Academic Search

A hydroxyapatite (HA, Ca10(PO4)6(OH)2), transformed from a calcium-containing borate glass, has been investigated for its protein adsorption and chromatographic\\u000a characteristics. Microspheres of the borate glass were transformed into HA by reacting them with a 0.25 M phosphate (K2HPO4) solution for 24 h at 37 °C (pH 9.0). The HA microspheres with a diameter of 45–90 ?m were hand packed into a steel column\\u000a (4.6 mm × 80 mm)

Xue Han; Ming Du; Yinfa Ma; Delbert E. Day

2008-01-01

63

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

64

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

65

Atom probe tomography of lithium-doped network glasses.  

PubMed

Li-doped silicate and borate glasses are electronically insulating, but provide considerable ionic conductivity. Under measurement conditions of laser-assisted atom probe tomography, mobile Li ions are redistributed in response to high electric fields. In consequence, the direct interpretation of measured composition profiles is prevented. It is demonstrated that composition profiles are nevertheless well understood by a complex model taking into account the electronic structure of dielectric materials, ionic mobility and field screening. Quantitative data on band bending and field penetration during measurement are derived which are important in understanding laser-assisted atom probe tomography of dielectric materials. PMID:24713345

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

2014-06-01

66

Effect of alkali content on AC conductivity of borate glasses containing two transition metals  

NASA Astrophysics Data System (ADS)

Sodium borate glasses containing iron and molybdenum ions with the total concentration of transition ions constant and gradual substitution of sodium oxide (network modifier) by borate oxide (network former) was prepared. Densities, molar volume, DC and AC conductivities are measured. The trends of these properties are attributed to changes in the glass network structure. Their DC and AC conductivity increased with increasing NaO concentration. The increase of AC conductivity of sodium borate glasses is attributed to the chemical composition and the hopping mechanism of conduction. Measurements of the dielectric constant ( ?) and dielectric loss (tan ?) as a function of frequency (50 Hz-100 kHz) and temperature (RT-600 K) indicate that the increase in dielectric constant and loss ( ? and tan ?) values with increasing sodium ion content could be attributed to the assumption that Fe and Mo ions tend to assume network-forming position in the glass compositions studied. The variation of the value of frequency exponent s for all glass samples as the function of temperature at a definite frequency indicates that the value of s decreases with increasing the temperature which agrees with the correlated barrier-hopping (CBH) model.

Kashif, I.; Rahman, Samy A.; Soliman, A. A.; Ibrahim, E. M.; Abdel-Khalek, E. K.; Mostafa, A. G.; Sanad, A. M.

2009-11-01

67

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

NASA Astrophysics Data System (ADS)

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

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

2013-04-01

68

Vitrification of borate waste from nuclear power plant using coal fly ash. (I) Glass formulation development  

Microsoft Academic Search

Borate waste, which is the main liquid waste from daily operation of PWR nuclear power plants, contains a large amount of Na and B. The coal fly ash is a by-product of the coal combustion power plants. The high content of SiO2 and Al2O3 of coal fly ash makes it a desirable glass network former additive; therefore, using the coal

Jiawei Sheng

2001-01-01

69

Electrical conductivity of silver bismuth borate tellurite glasses  

NASA Astrophysics Data System (ADS)

The AC electrical conductivity of (Ag 2O) x (Bi 2O 3) 30 (B 2O 3) 60-x (TeO 2) 10 glass ( x=0, 2, 4, 5, 10, 15 and 20) were measured at different temperatures and frequencies. The results obtained indicated that glasses containing silver<5 mol% have values nearly approximately equal to AC electrical conductivity. A slight decrease was observed with increasing Ag 2O concentration up to 4 mol%. However, the AC electrical conductivity values increase with increasing silver content, i.e. ?5 mol%. The AC electrical conductivity values, increased with increasing frequency and follow the power law, ?AC= A?s. The frequency exponent s was found to be dependent on frequency and temperature. The s values tended to increase to unity as the temperature decreased. Such results suggest that the correlated barrier-hopping (CBH) model is appropriate for explaining the AC electrical conductivity in these glasses. A pronounced increase in the dielectric loss values was observed with increasing silver content. These reflect the effect of Ag + ions charge carriers on the electrical conductivity of such glasses.

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

2008-07-01

70

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

71

Correlation of ion dynamics with characteristic length scales and network structural units in bismuth borate glasses  

NASA Astrophysics Data System (ADS)

Ion dynamics in lithium bismuth borate conducting glasses have been reported in wide composition and temperature ranges. The activation energy for the dc conduction has been analysed using Anderson-Stuart model and a correlation between the dc conductivity and the doorway radius has been predicted. The characteristic length scales for ion dynamics, such as mean square displacement and spatial extent of sub-diffusive motion of lithium ions have been determined from the ac conductivity and dielectric spectra, respectively. A direct connection between the ion dynamics and the characteristic length scales and the network structural units have been established.

Shaw, A.; Ghosh, A.

2013-09-01

72

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

73

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

74

Structure and neutron imaging characteristics of lithium borate barium chloride glass-ceramics  

NASA Astrophysics Data System (ADS)

A glass-ceramic has been developed which can be used as a thermal neutron imaging plate (NIP) for neutron radiography. The plate consists of nanocrystallites of the storage phosphor BaCl 2:Eu 2+ embedded within a neutron sensitive lithium borate glass-matrix. Details of their preparation and structure are discussed. Neutron images were read out using a Fuji BAS2500 imaging plate scanner and the quality of the images obtained is comparable to those recorded on a commercial NIP. Details of the response to neutron and X-irradiation as well as the obtained spatial resolution of the images are presented. The neutron activation of the materials studied is also calculated.

Appleby, G. A.; Edgar, A.; Williams, G. V. M.; Vontobel, P.

2006-08-01

75

UV-VIS-NIR spectral optical properties of silver iodide borate glasses  

NASA Astrophysics Data System (ADS)

We present a study of optical properties of a series of silver iodide borate glasses(AgI)x(Ag2O·B2O3)1-xby UV-VIS-NIR spectroscopy. The results show an increased absorbance in the whole analysed spectral range when the AgI concentration is augmented. In particular, the enhanced intensity of the wavelength band at 400-500 nm with silver iodine content suggests that this band arises from plasmon-related absorption, describing the formation of silver nanoparticles. With respect to this study, our results could motivate novel target designs consisting of ternary silver boron based bulk glasses for generating resonant absorption of laser light by plasma.

Crupi, C.; Di Marco, G.; Torrisi, L.; Branca, C.; Carini, G.; Wanderlingh, U.; D'Angelo, G.

2014-04-01

76

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

77

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

PubMed Central

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

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

2014-01-01

78

Effect of silver nanoparticles on the fluorescence of Pb2+ and compositional dependence of Sm3+ fluorescence in borate glasses  

NASA Astrophysics Data System (ADS)

Borate glasses have been widely studied due to their good optical and mechanical properties. Lead and bismuth (PbO/Bi2O 3:B2O3) borate glasses belong to a family of heavy metal oxide (HMO) glasses which are well known to be chemically durable, stable against atmospheric moisture, have low melting temperatures and good corrosion resistance. The first part of this work deals with lead borate glasses with silver nanoparticles (NPs) introduced into the glass matrix. Transmission electron microscopy characterization is done to verify the nucleation of NPs. Fluorescence and optical absorption experiments are then carried out after different heat treatment duration to investigate the influence of silver NPs on the optical properties of lead (Pb2+) by comparing with a glass sample without silver NPs. Optical absorption experiments show that a well-defined surface plasmon resonance (SPR) peak due to Ag NPs can be observed only for samples that were annealed for 36 hrs. Pb2+ fluorescence spectra reveal that the presence of silver NPs creates new emission centers for Pb2+ ions by altering their chemical environment. The second part of the work involves the use of samarium (a rare earth ion) as a dopant in lead and bismuth borate glasses. The concentration of samarium (Sm3+) is fixed and the base glass composition is varied. The goal is to investigate the compositional dependence of optical properties of samarium in the base glass (PbO/Bi2O3:B 2O3). Optical absorption spectra have been collected and the oscillator strength of each transition - including the hypersensitive - is obtained. The Optical absorption edge is found to shift toward lower energies with increasing PbO/Bi2O3 concentration. Both the oscillator strength and the peak position of the hypersensitive transition show significant variation with glass composition. Strong interaction between Sm3+ ions and Pb2+/Bi3+ ions can also be seen from the variations in the fluorescence emission properties of Sm3+ as a function of base glass composition. Studying the variation of these optical properties will help to create the optimum rare-earth ion-host configuration for possible technological applications. This is the thrust of our future investigations of these glass systems. Keywords: Borate glasses, nanoparticles, fluorescence, transmission electron microscopy, optical absorption, surface plasmon resonance, rare-earth (RE) ions, oscillator strength, hypersensitive transition (HST).

Olumoroti, Akinloluwa T.

79

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

80

Thermally activated relaxations and vibrational anharmonicity in alkali-borate glasses: Brillouin scattering study  

NASA Astrophysics Data System (ADS)

Measurements of Brillouin light scattering have been performed in (M2O)0.14(B2O3)0.86 alkali-borate glasses, where M=Li and K, as a function of temperature between 15 and 300 K. The temperature behaviors of hypersonic attenuation and velocity have been explained in terms of thermally activated relaxations of intrinsic structural defects and of anharmonic interactions between hypersonic waves and thermal vibrational modes. In the temperature region above 150 K, where the mean free path of thermal modes is shorter than the acoustic wavelength, it has been shown that the sound propagation is mainly regulated by the Akhiezer mechanism of “phonon viscosity.” It causes a linear increase in the hypersonic attenuation and a linear decrease in the sound velocity with increasing temperature.

Carini, Giovanni, Jr.; Tripodo, Gaspare; Borjesson, Lars

2008-07-01

81

Optical properties of amorphous, erbium-doped yttrium alumino-borate thin films  

NASA Astrophysics Data System (ADS)

In this paper, we report on the optical characterizations of erbium-doped yttrium alumino-borate glassy thin films prepared by the polymeric precursor and sol-gel routes and the spin-coating technique. High quality planar waveguides were produced by a multilayer processing of Y 1-xEr xAl 3(BO 3) 4 compositions with x = 0.02, 0.05, 0.10, 0.30, and 0.50. Their optical properties were investigated using transmission, photoluminescence, and m-lines spectroscopy, whereas high resolution scanning electron microscopy (HR-SEM) was applied to check film thickness and surface homogeneity. The refractive indices determined from transmission and m-lines spectroscopy are in good agreement just like the film thickness measured by HR-SEM and transmission spectroscopy. We observed low propagation losses, together with efficient photoluminescence emission for polymeric precursor thin films, involving low cost and environment friendly reactants.

Maia, L. J. Q.; Fick, J.; Hernandes, A. C.; Mastelaro, V. R.; Ibanez, A.

2012-02-01

82

Ag doped chalcogenide glasses and their applications  

Microsoft Academic Search

Ag-doped chalcogenide glasses and amorphous thin films, their preparation, properties, photodoping, photoinduced surface deposition and applications, are reviewed, expanding on the results obtained recently. The progress obtained is not only connected with better understanding of their structure, chemical bonding and properties but also in application of Ag-containing glasses and films in solid-state batteries, electrochemical sensors and optoelectronics (gratings, microlenses, waveguides,

Miloslav Frumar; Tomas Wagner

2003-01-01

83

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

84

Optical and FTIR spectra of NdF3-doped borophosphate glasses and effect of gamma irradiation  

NASA Astrophysics Data System (ADS)

UV-visible, FTIR absorption spectra of some prepared undoped and NdF3-doped borophosphate glasses with varying dopant contents were studied before and after gamma irradiation. The base undoped borophosphate glass exhibits strong UV absorption which is related to the presence of unavoidable trace iron impurities within the chemicals used for the preparation of such glass. NdF3-doped samples show characteristic bands specifically at high concentration which are attributed to the Nd3+ ions. Gamma irradiation on the undoped borophosphate glass causes no obvious induced defects. On the other hand, the low NdF3 content glass produces extended UV absorption together with the resolution of an extra induced visible at about 500 nm. On increasing the NdF3 content, gamma irradiation retains the characteristic bands due to Nd3+ ions. Infrared absorption spectra of undoped and NdF3-doped glasses reveal characteristic IR vibrational bands due to the combination of both phosphate and borate groups (BO3 and BO4) with the first phosphate partner dominating in response to the high percent (50 mol%). The introduction of NdF3 within the dopant level (1.5-6%) produces no distinct effect on the FTIR spectra. Gamma irradiation is observed to cause no obvious effects on the FTIR spectra which is related to the stability of mixed phosphate and borate units causing the compactness and resistance towards gamma irradiation.

ElBatal, F. H.; Ibrahim, S.; Abdelghany, A. M.

2012-12-01

85

Influence of modifier oxides on spectroscopic properties of Sm3+ doped lithium fluoroborate glass  

NASA Astrophysics Data System (ADS)

Sm3+ doped lithium fluoro-borate glasses with different modifier oxides (Li2B4O7-BaF2-NaF-MO where M = Mg, Ca, Cd and Pb) and combinations of modifier oxides (Li2B4O7-BaF2-NaF-MgO+CaO, Li2B4O7-BaF2-NaF-CdO+PbO) were prepared by means of melt quenching method. These samples were characterized by XRD, FTIR, optical absorption and fluorescence techniques at room temperature. The XRD profiles of all the glasses confirm their amorphous nature and the FTIR spectra reveal the presence of BO3 and BO4 units along with the strong OH- groups in the glass matrices. The influence of modifier oxides on Judd-Ofelt (J-O) intensity parameters and intensity of the emission lines are reported. Judd-Ofelt theory is used to study the spectral properties and to calculate the radiative transition probabilities (AT), branching ratios (?R), integrated absorption cross sections (?) and radiative lifetimes (?R) for certain spectral transitions. From the emission spectral analysis, emission cross-sections (?P) are calculated for the four emission transitions, 4G5/2 ? 6H5/2, 4G5/2 ? 6H7/2, 4G5/2 ? 6H9/2 and 4G5/2 ? 6H11/2 of Sm3+ ion in different lithium fluoro-borate glasses. Among the four transitions, it is observed that the transition 4G5/2 ? 6H7/2 has higher emission cross-section (?P) in all the glass matrices, except in Mg, Cd and Mg-Ca glass matrices. The non-exponential nature of the luminescence decay curves of 4G5/2 level of Sm3+ doped glass matrices are also reported.

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

2012-11-01

86

Luminescent thermochromism in potassium-alumina-borate glass with copper-containing molecular clusters at elevated temperatures  

NASA Astrophysics Data System (ADS)

It is experimentally shown that a considerable luminescent thermochromic effect occurs in potassium-alumina-borate (PAB) glasses with copper-containing molecular clusters. This effect is manifested in a reversible blue spectral shift of luminescence band about 100 nm and its narrowing, with negligible change of luminescence amplitude in maximum during heating from 20 up to 300 °C. Luminescence and excitation spectra of PAB glass at different temperatures are presented. It is shown that the temperature rise results in a red spectral shift of excitation bands and in their broadening.

Babkina, Anastasiya N.; Nikonorov, Nikolaij V.; Shakhverdov, Teimur A.; Shirshnev, Pavel S.; Sidorov, Alexander I.

2014-02-01

87

Low loss photonic components in high index bismuth borate glass by femtosecond laser direct writing.  

PubMed

Single mode, low loss waveguides were fabricated in high index bismuth borate glass by femtosecond laser direct writing. A specific set of writing parameters leading to waveguides perfectly mode matched to standard single-mode fibers at 1.55 microm with an overall insertion loss of approximately 1 dB and with propagation loss below 0.2 dB/cm was identified. Photonic components such as Y-splitters and directional couplers were also demonstrated. A close agreement between their performances and theoretical predictions based upon the characterization of the waveguide properties is shown. Finally, the nonlinear refractive index of the waveguides has been measured to be 6.6 x 10(-15) cm(2)/W by analyzing self-phase modulation of the propagating femtosecond laser pulse at the wavelength of 1.46 microm. Broadening of the transmitted light source as large as 500 nm was demonstrated through a waveguide with the length of 1.8 cm. PMID:18825261

Yang, Weijia; Corbari, Costantino; Kazansky, Peter G; Sakaguchi, Koichi; Carvalho, Isabel C S

2008-09-29

88

Rare earth-doped glass microbarcodes  

PubMed Central

The development of ultraminiaturized identification tags has applications in fields ranging from advanced biotechnology to security. This paper describes micrometer-sized glass barcodes containing a pattern of different fluorescent materials that are easily identified by using a UV lamp and an optical microscope. A model DNA hybridization assay using these “microbarcodes” is described. Rare earth-doped glasses were chosen because of their narrow emission bands, high quantum efficiencies, noninterference with common fluorescent labels, and inertness to most organic and aqueous solvents. These properties and the large number (>1 million) of possible combinations of these microbarcodes make them attractive for use in multiplexed bioassays and general encoding. PMID:12515864

Dejneka, Matthew J.; Streltsov, Alexander; Pal, Santona; Frutos, Anthony G.; Powell, Christy L.; Yost, Kevin; Yuen, Po Ki; Muller, Uwe; Lahiri, Joydeep

2003-01-01

89

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

90

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

91

Defect formation of gamma irradiated MoO3-doped borophosphate glasses  

NASA Astrophysics Data System (ADS)

Borophosphate glasses of the basic composition (50P2O5, 30B2O3, 20Na2O mol%) containing different doping molybdenum oxide percents (0.16-0.98) were prepared by melting and annealing method. Infrared and UV-visible absorption spectroscopic measurements before and after gamma irradiation were carried out. The base undoped borophosphate glass reveals strong UV absorption bands but with no visible bands and these UV bands are related to unavoidable trace iron impurities contaminated within the raw materials used for the preparation of this glass. The introduction of MoO3 (in doping ratio) into this glass produces an additional UV band and a broad visible band and their intensities increase with the MoO3 content. These additional bands are related to both Mo6+ and Mo5+ ions. The base undoped borophosphate glass shows retardation effect towards gamma irradiation. Gamma irradiation produces marked changes in the UV-visible spectra of Mosbnd O3-doped glasses. Such changes can be related to the production of induced defects from photochemical reactions and the generation of positive holes. Infrared absorption spectrum of the undoped borophosphate glass reveals complex vibrational bands due to the presence of both phosphate groups beside borate groups with triangular and tetrahedrally coordinated units. The introduction of MoO3 causes some limited variations in the FTIR spectra. Gamma irradiation produces minor changes in the intensities of some IR bands. Such changes are related to the changes in the bond angles and/or bond lengths of few structural groups upon irradiation while the main structural groups remain unchanged in their number and position.

Abdelghany, A. M.; Ouis, M. A.; Azooz, M. A.; EllBatal, H. A.

2013-10-01

92

Defect formation of gamma irradiated MoO3-doped borophosphate glasses.  

PubMed

Borophosphate glasses of the basic composition (50P2O5, 30B2O3, 20Na2O mol%) containing different doping molybdenum oxide percents (0.16-0.98) were prepared by melting and annealing method. Infrared and UV-visible absorption spectroscopic measurements before and after gamma irradiation were carried out. The base undoped borophosphate glass reveals strong UV absorption bands but with no visible bands and these UV bands are related to unavoidable trace iron impurities contaminated within the raw materials used for the preparation of this glass. The introduction of MoO3 (in doping ratio) into this glass produces an additional UV band and a broad visible band and their intensities increase with the MoO3 content. These additional bands are related to both Mo(6+) and Mo(5+) ions. The base undoped borophosphate glass shows retardation effect towards gamma irradiation. Gamma irradiation produces marked changes in the UV-visible spectra of Mo-O3-doped glasses. Such changes can be related to the production of induced defects from photochemical reactions and the generation of positive holes. Infrared absorption spectrum of the undoped borophosphate glass reveals complex vibrational bands due to the presence of both phosphate groups beside borate groups with triangular and tetrahedrally coordinated units. The introduction of MoO3 causes some limited variations in the FTIR spectra. Gamma irradiation produces minor changes in the intensities of some IR bands. Such changes are related to the changes in the bond angles and/or bond lengths of few structural groups upon irradiation while the main structural groups remain unchanged in their number and position. PMID:23800775

Abdelghany, A M; Ouis, M A; Azooz, M A; Ellbatal, H A

2013-10-01

93

IR luminescence in bismuth-doped germanate glasses and fibres  

SciTech Connect

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

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

2013-02-28

94

Emission mechanism of radiophotoluminescence in Ag-doped phosphate glass  

Microsoft Academic Search

The objective of this study is to investigate the emission mechanism of radiophotoluminescence (RPL) in the Ag+-doped phosphate glass (glass dosimeter), which is now used as individual radiation dosimeter, because the emission mechanism of RPL in glass dosimeter was not fully understood. Optical properties such as optical absorption spectrum, RPL spectrum and change of RPL spectrum as a function of

Y. Miyamoto; T. Yamamoto; K. Kinoshita; S. Koyama; Y. Takei; H. Nanto; Y. Shimotsuma; M. Sakakura; K. Miura; K. Hirao

2010-01-01

95

Structural models for yttrium aluminium borate laser glasses: NMR and EPR studies of the system (Y2O3)(0.2)-(Al2O3)x-(B2O3)(0.8-x).  

PubMed

The structure of laser glasses in the system (Y(2)O(3))(0.2){(Al(2)O(3))(x))(B(2)O(3))(0.8-x)} (0.15 ? x ? 0.40) has been investigated by means of (11)B, (27)Al, and (89)Y solid state NMR as well as electron spin echo envelope modulation (ESEEM) of Yb-doped samples. The latter technique has been applied for the first time to an aluminoborate glass system. (11)B magic-angle spinning (MAS)-NMR spectra reveal that, while the majority of the boron atoms are three-coordinated over the entire composition region, the fraction of three-coordinated boron atoms increases significantly with increasing x. Charge balance considerations as well as (11)B NMR lineshape analyses suggest that the dominant borate species are predominantly singly charged metaborate (BO(2/2)O(-)), doubly charged pyroborate (BO(1/2)(O(-))(2)), and (at x = 0.40) triply charged orthoborate groups. As x increases along this series, the average anionic charge per trigonal borate group increases from 1.38 to 2.91. (27)Al MAS-NMR spectra show that the alumina species are present in the coordination states four, five and six, and the fraction of four-coordinated Al increases markedly with increasing x. All of the Al coordination states are in intimate contact with both the three- and the four-coordinate boron species and vice versa, as indicated by (11)B/(27)Al rotational echo double resonance (REDOR) data. These results are consistent with the formation of a homogeneous, non-segregated glass structure. (89)Y solid state NMR spectra show a significant chemical shift trend, reflecting that the second coordination sphere becomes increasingly "aluminate-like" with increasing x. This conclusion is supported by electron spin echo envelope modulation (ESEEM) data of Yb-doped glasses, which indicate that both borate and aluminate species participate in the medium range structure of the rare-earth ions, consistent with a random spatial distribution of the glass components. PMID:21814672

Deters, Heinz; de Lima, José F; Magon, Claudio J; de Camargo, Andrea S S; Eckert, Hellmut

2011-09-21

96

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

97

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

98

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

99

Porous silicon - rare earth doped xerogel and glass composites  

NASA Astrophysics Data System (ADS)

The development of components for photonics applications is growing exponentially. The sol-gel method is now recognised as a convenient and flexible way to deposit oxide or glass films on a variety of hosts, including porous silicon. In the present work we incorporated erbium and europium doped xerogel into porous silicon and developed new porous silicon - rare earth doped glass composites. Various characteris-ation techniques including FTIR, Raman Spectroscopy, Thermal Gravimetric Analysis and Scanning Electron Microscopy were employed in this work.

Balakrishnan, S.; Gun'ko, Yurii K.; Perova, T. S.; Rafferty, A.; Astrova, E. V.; Moore, R. A.

2005-06-01

100

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

101

Gamma rays interaction with copper doped lithium phosphate glasses  

NASA Astrophysics Data System (ADS)

Undoped and copper-doped lithium phosphate glasses were prepared. CuO-doped glasses possess characteristic greenish color which deepens with the increase of CuO content. Experimental optical absorption spectra of the undoped lithium phosphate glasses reveal strong ultraviolet absorption bands and no visible bands are observed. These strong UV bands are assumed to originate from unavoidable trace iron ions contamination within the chemicals used for the preparation of the glass. The optical absorption spectra of the CuO-doped phosphate glasses reveal the same UV absorption as observed in the undoped samples beside an extra broad visible absorption band which splits to some component peaks. Such visible spectra are related to the presence of divalent copper (Cu2+) ions in distorted octahedral coordination. Gamma irradiation of the undoped sample produces induced defects generated through the liberation of pairs of electrons and positive holes. CuO-doped glasses show some shielding behavior towards successive gamma irradiation especially at high CuO contents. FTIR absorption spectra of the studied glasses indicate the appearance of characteristic vibrational bands due to phosphate groups. Gamma irradiation causes minor effects on the FTIR spectra, but the bands due to water molecules are strongly affected by gamma irradiation because of loose bonding within the glass network.

ElBatal, Hatem A.; ElMandouh, Zeinab E.; Zayed, Hamdia A.; Marzouk, Samir Y.; Elkomy, Gihan M.; Hosny, Ahmed

2013-12-01

102

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

NASA Astrophysics Data System (ADS)

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

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

2012-12-01

103

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

PubMed

Undoped and transition metals (3d TM) doped sodium borophosphate glasses were prepared. UV-visible absorption spectra were measured in the region 200-900nm before and after gamma irradiation. Experimental optical data indicate that the undoped sodium borophosphate glass reveals before irradiation strong and broad UV absorption and no visible bands could be identified. Such UV absorption is related to the presence of unavoidable trace iron impurities within the raw materials used for preparation of this base borophosphate glass. The TMs-doped glasses show absorption bands within the UV and/or visible regions which are characteristic to each respective TM ion in addition to the UV absorption observed from the host base glass. Infrared absorption spectra of the undoped and TMs-doped glasses reveal complex FTIR consisting of extended characteristic vibrational bands which are specific for phosphate groups as a main constituent but with the sharing of some vibrations due to the borate groups. This criterion was investigated and approved using DAT (deconvolution analysis technique). The effects of different TMs ions on the FTIR spectra are very limited due to the low doping level (0.2%) introduced in the glass composition. Gamma irradiation causes minor effect on the FTIR spectra specifically the decrease of intensities of some bands. Such behavior is related to the change of bond angles and/or bond lengths of some structural building units upon gamma irradiation. PMID:22995547

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

2012-12-01

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

Flame retardancy mechanisms of aluminium phosphinate in combination with melamine polyphosphate and zinc borate in glass-fibre reinforced polyamide 6,6  

Microsoft Academic Search

The fire retardancy mechanisms of aluminium diethylphosphinate in combination with melamine polyphosphate and zinc borate was analysed in glass-fibre reinforced polyamide 6,6. The influence of phosphorus compounds on the polyamide decomposition pathways was characterized using thermal analysis (TG), evolved gas analysis (TG–FTIR), and FTIR–ATR analysis of the residue. The Lewis acid–base interactions between the flame retardants, the amide unit, and

Ulrike Braun; Bernhard Schartel; Mario A. Fichera; Christian Jäger

2007-01-01

106

Electronic polarizability and interaction parameter of gadolinium tungsten borate glasses with high WO3 content  

NASA Astrophysics Data System (ADS)

Glasses with the compositions of 25Gd2O3-xWO3-(75-x)B2O3 with x=25-65 were prepared by using a conventional melt quenching method, and their electronic polarizabilities, optical basicities ?(no), and interaction parameters A(no) were estimated from density and refractive index measurements in order to clarify the feature of electronic polarizability and bonding states in the glasses with high WO3 contents. The optical basicity of the glasses increases monotonously with the substitution of WO3 for B2O3, and contrary the interaction parameter decreases monotonously with increasing WO3 content. A good linear correlation was observed between ?(no) and A(no) and between the glass transition temperature and A(no). It was proposed that Gd2O3 oxide belongs to the category of basic oxide with a value of A(no)=0.044 Å-3 as similar to WO3. The relationship between the glass formation and electronic polarizability in the glasses was discussed, and it was proposed that the glasses with high WO3 and Gd2O3 contents would be a floppy network system consisting of mainly basic oxides.

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

2014-12-01

107

Effects of fast neutron and gamma irradiation on electrical conductivity of some borate glasses  

Microsoft Academic Search

Electrical conductivity of samples of Li2O–B2O3 binary glass system containing Al2O3, PbO, Fe2O3, TiO2 or V2O5 was measured at temperatures ranging between 30 and 200 °C before and after irradiation with fast neutrons or ?-rays. Base and Al2O3-containing glasses showed an initial rise in conductivity with the increasing temperature, followed by a steep drop, then a more gradual increase. Glass

N. A. Elalaily; R. M. Mahamed

2002-01-01

108

Impedance spectroscopic characterization of Sm2O3 containing lithium borate glasses.  

PubMed

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. PMID:24929310

Ramteke, D D; Gedam, R S

2014-12-10

109

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

NASA Astrophysics Data System (ADS)

The DC Conductivity and Differential Thermal Analysis of glasses with composition (30-x)Li2O?xV2O5?20Bi2O3?50B2O3(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 (Tg) and crystallization temperature (Tx). 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.; Dahiya, M. S.; Agarwal, A.

2014-04-01

110

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

111

In-volume waveguides by fs-laser direct writing in rare-earth-doped fluoride glass and phosphate glass  

Microsoft Academic Search

Refractive index modifications are fabricated in the volume of rare-earth-doped glass materials namely Er- and Pr-doped ZBLAN (a fluoride glass consisting of ZrF4, BaF2, LaF3, AlF3, NaF), an Er-doped nano-crystalline glass-ceramic and Yb- and Er-doped phosphate glass IOG. Femtosecond laser radiation (tau=500fs, lambda=1045nm, f=0.1-5MHz) from an Ybfiber laser is focused with a microscope objective in the volume of the glass

D. Esser; D. Wortmann; J. Gottmann

2009-01-01

112

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

113

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

Microsoft Academic Search

The results of magnetic measurements performed on xFe2O3(1?x)[yB2O3 PbO] glasses having y=0.5, 1, 2, and 3 and x?25 mol % Fe2O3 are reported. For identical Fe2O3 content the Curie constants are greater as the PbO content of the glass matrix is higher. This is due to the increase of the fraction of Fe3+ ions as evidenced by Mo¨ssbauer effect measurements.

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

1985-01-01

114

Efficiency and tuning of the erbium-doped glass lasers  

NASA Astrophysics Data System (ADS)

Erbium-doped glass lasers operated near by 1 5 mm wavelength are helpful for medicine and biology optical communication and eye-safe range finder systems. Advances in erbium-doped glass especially phosphate glass and lasers based on it have been extensive in recent years. Nowadays we can approve that erbium glass lasers are not worse compared with the neodymium ones by many spectroscopic and laser properties. Developments of the energy spectral and temporal characteristics and tuning near the 1500 nm wavelength of the erbium - doped phosphate glass lasers are reported. 2. SPECTROSCOPIC PECULIARITIES OF THE ERBIUM DOPED GLASS Phosphate erbium-doped glass possess a number of spectroscopic peculiarities as a laser active medium. Energy level diagrams of Er3 ions and two other its co-doped ions -Yb3 and Cr3 and the actual transitions (radiate and nonradiate) between them are shown in Fig. 1 (a). Absorption spectrum of that phosphate glass is also shown in Fig. 1 (b) . One can see that the whole pum energy is absorbed only by coactivators - Yb Cr - Yb E r and Cr3 - and then quickly and efficiently transferred from them to Er3 ions. Thus ''7 lasing and pumping of the erbium glass are ''4 realized by means of quite different ions. 4 Thanks to that one can get a low laser threshold t1/2 usin a small doping of Er3 ions (about 1019 I3/2 cm ) and the same time have a high efficient 4T pumoing by using the big concentration of ions 15/2 Yb3 and Cr3 in them (1021 cm3 and 1020 b cm3 accordingly). Obstacles for high efficiency of the lasers may be connected with either increase of the back pump energy transfer from Yb3 ions to Cr3 ones by too large concentration of Cr3 ions or thermal distortions of the active medium. Optimal pumping conditions for lamp pumped Er - doped glass laser differ from neodymium ones. It is explained by the important role of pump energy transfer processes in Er - doped glass. In order to have of high efficient pumping it is necessary that energy transfer rates from Yb3 to Er3 - 3+ 3+ WybEr and from Cr to Yb - WCrYb would be a lot of more then pumping rate W p (mainly object to WYbEr W1). It means the need to use pump pulse durations of about 1O - 102 s and more in that lasers. 3. EFFICIENCY AND THERMAL DISTORTIONS IN THE LASERS Efficiency of the lamp pumped Cr - Yb - Er doped phosphate glass oscillator can be up to 3 or some more (slope efficiency is up to 3. 5 ) /1 at free - running operation and storage efficiency of amplifiers based on the glass can be up to 1. 2 / 3 /. It was achieved

Fromzel, Victor A.; Kuchma, Igor G.; Lunter, Sergei G.; Mak, Artur A.; Petrov, Aleksey A.

1992-11-01

115

Lead borophosphate glasses doped with titanium dioxide  

Microsoft Academic Search

Glasses of the compositional series of 50PbO–yB2O3–(50?y)P2O5–xTiO2 (with x=0–16) have been prepared and characterized by the determination of density, molar volume, glass transition temperature, dilatation softening temperature, thermal and chemical durability. Structural changes were evaluated from the studies by 31P and 11B MAS NMR, Raman and infrared spectroscopy. Molar volume of the glasses decreases and the glass transition temperature increases

L. Koudelka; P Mošner; M Zeyer; C Jäger

2003-01-01

116

Synthesis of novel organic-ligand-doped sodium bis(oxalate)-borate complexes with tailored thermal stability and enhanced ion conductivity for sodium ion batteries  

NASA Astrophysics Data System (ADS)

A series of novel organic-ligand-doped sodium bis(oxalate)-borate complexes, including sodium bis[salicylato(2-)]-borate (NBSB), sodium[salicylato benzenediol]borate (NBDSB), sodium bis[oxalate]-borate (NBOB) and its derivatives NBOB(C2H2O4)0.2, NBOB(C7H4O3)0.2, NBOB(C7H4O3)0.6, NBOB(C6H6O2)0.15 and NBOB(C6H6O2)0.3 fabricated by solid-state reaction are firstly developed as new-type electrolytes for sodium ion batteries. These resulting sodium boron salts possess good solubility in an abroad range of organic solvents (such as PC, AN, DMF, PC + AN, PC + DMF), tailored thermal stability from 300 to 353 °C, improved ion conductivity (>1 × 10-3 S cm-1), environmental friendliness and low cost. Therefore, we believe that these new-type sodium boron salts show great potential as a new class of electrolyte for high-performance sodium ion batteries.

Ge, Chunhua; Wang, Lixia; Xue, Lili; Wu, Zhong-Shuai; Li, Hehe; Gong, Zailin; Zhang, Xiang-Dong

2014-02-01

117

Fluorescence properties of Eu3+-doped alumino silicate glasses  

NASA Astrophysics Data System (ADS)

Alumino silicate glasses of a very broad range of molar compositions doped with 1 ? 1020 Eu3+ cm-3 (about 0.2 mol% Eu2O3) were prepared. As network modifier oxides Li2O, Na2O, K2O, MgO, CaO, SrO, BaO, ZnO, PbO, Y2O3 and La2O3 have been used. All glasses show relatively broad fluorescence excitation and emission spectra. For most glasses only a weak effect of the glass composition on the excitation and emission spectra is observed. Although the glasses should be structurally similar, notable differences are found for the fluorescence lifetimes. These increase steadily with decreasing mean atomic weight, decreasing refractive index and decreasing optical basicity of the glasses, which may be explained by local field effects. An exception from this rule are the strontium, barium and potassium containing glasses, which show significantly increased fluorescence lifetimes despite of their high refractive index, optical basicity and molecular weight. The non mono-exponential fluorescence decay curves as well as the fluorescence spectra indicate a massive change in the local surroundings of the doped rare earth ions for these glasses.

Herrmann, Andreas; Kuhn, Stefan; Tiegel, Mirko; Rüssel, Christian

2014-11-01

118

Thermal and optical properties of tellurite glasses doped erbium  

Microsoft Academic Search

Er3+-doped tellurite glasses with molar compositions of 75TeO2–20ZnO–(5 ? x) Na2O–xEr2O3 (x = 0, 0.5, 1, 2, 3, and 4 mol%) have been elaborated from the melt-quenching method. The effects of Er2O3 concentration on the thermal stability and optical properties of tellurite glasses have been discussed. From the differential\\u000a scanning calorimetry (DSC) profile, the glass transition temperature T\\u000a g, and crystallization onset temperature T\\u000a x

I. Jlassi; H. Elhouichet; M. Ferid

2011-01-01

119

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

SciTech Connect

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

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

1985-11-01

120

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

121

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

122

Exceptionally narrow homogeneous linewidth in erbium-doped glasses  

NASA Astrophysics Data System (ADS)

We show that rare-earth (RE-) doped glasses can have homogeneous linewidths as narrow as 287 kHz at 4He temperatures. This is far narrower than others reported in glasses in the same temperature range and is suitable for precise spectral hole burning and spatial-spectral holographic applications. It is known that cw spectral hole burning linewidth measurements of RE ions in glasses are hindered by the presence of spectral diffusion but, even in glasses, application of a magnetic field can freeze out RE spin-spin interactions responsible for spectral diffusion and isolate the remaining contribution of two-level systems (TLSs). The Er3+:2G2S glasses have unusually low TLS contributions, making it possible to study the real homogeneous linewidth using photon echo measurements. The contribution from TLSs is only 170 T1.3 kHz when subjected to a field of 5 T.

Sun, Y.; Cone, R. L.; Bigot, L.; Jacquier, B.

2006-12-01

123

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

124

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

125

Spectral studies of Erbium doped heavy metal borophosphate glass systems  

NASA Astrophysics Data System (ADS)

The ternary lead bismuth magnesium borophosphate glass system (LBMBPE) with molar concentrations of (50- x) PbO- xBi 2O 3-25MgHPO 4-24B 2O 3-1Er 2O 3 ( x=10, 20, 30 and 40) was prepared using Melt quenching technique. The amorphous nature of these glass samples were confirmed with XRD studies, The spectral data from the optical absorption studies was employed to compute the spectroscopic parameters such as Racah coefficients ( E1, E2 and E3), spin-orbit coupling (? 4 f), configuration interaction factor ( ?) and Judd-Ofelt intensity parameters ( ??, ?=2, 4 and 6). The IR spectra exhibit the presence of vibrational modes of phosphates, borate radicals, bismuth, lead and magnesium ions. The Judd-Ofelt parameterization indicates the covalency and vibrationonic frequencies of the ligands with rare earth ions. The radiative parameters such as radiative transition probabilities (A), the total radiative transitional probabilities ( AT), radiative life times ( ?R), branching ratios ( ?) and absorption cross sections (?) were computed for certain lasing levels. The effect of compositional changes on the optical band gap is also reported. The glass systems thus developed indicate their potential lasing candidature.

Ravi Babu, Y. N. Ch.; Sree Ram Naik, P.; Vijaya Kumar, K.; Prasad, S. V. G. V. A.; Suresh Kumar, A.

2012-02-01

126

Glass-crystal transition in silver-iodide-doped silver selenomolybdate glasses  

NASA Astrophysics Data System (ADS)

In this paper, we have studied the isothermal and non-isothermal glass-crystal transition in AgI-doped silver selenomolybdate glasses using differential scanning calorimetry. We have observed a strong dependence of AgI on the glass-crystal transition of these glasses. The activation energy for the crystallization and the dimensionality of the crystal growth for the isothermal and non-isothermal crystallization processes have been determined. The dimensionality of the crystal growth depends strongly on the AgI content and intriguingly shows different behavior when compared for isothermal and non-isothermal cases. For the present glass system the John-Mehl-Avrami model describes well the isothermal crystallization kinetics, while the Sestak-Berggren model is more suitable to describe the non-isothermal crystallization kinetics for glass-crystal transformation.

Deb, B.; Ghosh, A.

2013-12-01

127

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

Microsoft Academic Search

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 F 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

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

2009-01-01

128

Optical properties and energy transfer of Dy 3+-doped transparent oxyfluoride glasses and glass–ceramics  

Microsoft Academic Search

Dysprosium-doped oxyfluoride glasses and nanocrystalline glass–ceramics have been synthesized and studied by X-ray diffraction, transmission electron microscope, optical spectroscopy and time-resolved decay curves measurements. From the absorption spectra, Judd–Ofelt intensity parameters have been obtained and are used to predict radiative properties for the excited states of Dy3+ ions. From the visible emission spectra, yellow to blue intensity ratios have been

P. Babu; Kyoung Hyuk Jang; Eun Sik Kim; Liang Shi; R. Vijaya; V. Lavín; C. K. Jayasankar; Hyo Jin Seo

2010-01-01

129

Spectral investigations on Dy3+-doped transparent oxyfluoride glasses and nanocrystalline glass ceramics  

Microsoft Academic Search

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 4F9\\/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

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

2009-01-01

130

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

131

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

132

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

133

Laser action in praseodymium doped zinc chloride borophosphate glasses  

Microsoft Academic Search

In order to predict laser action in praseodymium doped zinc chloride borophosphate glasses with the help of laser parameters both absorption and fluorescence spectra have been studied. The glass specimens having composition in mol% B2O3(14.57)–P2O5(44.85)–Na2O(26.08)–ZnCl2(14.50)–Pr6O11(R) (R=0.0, 0.1 and 0.2 mol%) have been prepared by melt quenching technique. The spectra consist of seven absorption bands (400–2400 nm) and three fluorescence bands

Y. K. Sharma; S. P. Tandon; S. S. L. Surana

2000-01-01

134

Laser action in neodymium-doped zinc chloride borophosphate glasses  

Microsoft Academic Search

Laser action has been predicted in neodymium-doped zinc chloride borophosphate glasses with the help of laser parameters for the transitions 4F3\\/2?4I9\\/2, 4F3\\/2?4I11\\/2 and 4F3\\/2?4I13\\/2 in the near-IR region. Judd–Ofelt parameters have been used for the calculations of different laser parameters. Various energy interaction parameters like Slater–Condon, Landé, Racah and bonding parameters have also been calculated. A comparison with borophosphate glasses

S. S. L. Surana; Y. K. Sharma; S. P. Tandon

2001-01-01

135

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

136

Spectroscopic ellipsometry investigations of Eu-doped oxy-fluoride glass and glass-ceramics  

NASA Astrophysics Data System (ADS)

Oxyfluoride glass-ceramics in the system SiO2-Al2O3-CaF2-EuF3 containing Eu3+-doped CaF2 nanocrystals were produced by using controlled crystallization of melt-quenched glass. X-ray diffraction and scanning electron microscopy data have revealed the formation of CaF2 nanocrystals of about 50 nm size. The Eu3+-dopant ions act as the nucleating agent necessary to initiate the crystallization process. The refractive index is higher in the glass ceramics than in the initial glass and varies as the annealing time increases. Two competitive processes are responsible for this behavior, the crystallization of the CaF2 phase and the decrease of the glass ceramic mass density.

Galca, A. C.; Preda, N.; Secu, C. E.; Luculescu, C. R.; Secu, M.

2012-06-01

137

Optically detected magnetic resonance in bismuth-doped silica glass.  

PubMed

We report on the observation of optically detected magnetic resonance (ODMR) in bismuth-doped silica glass. To explain the results of the experiment we adopted the intramolecular charge transfer model for Bi(5+)O(n)(2-) molecules in the frame of a semiempirical molecular orbitals approach. The results of our calculations are in good agreement with observed features of luminescence and ODMR experiments. PMID:19724534

Razdobreev, I; Ivanov, V Yu; Bigot, L; Godlewski, M; Kustov, E F

2009-09-01

138

Optical properties of Yb 3+-doped phosphate laser glasses  

Microsoft Academic Search

Ytterbium-doped phosphate glasses have been prepared and studied their spectroscopic properties through absorption, emission and Fourier transform infrared (FTIR) spectral studies and time-resolved luminescence decay curves. The absorption cross-section has been found to vary with the variation of Yb2O3 concentration. The results of the FTIR spectra show that the OH? content is increasing with increase of the Yb2O3 concentration in

V. Venkatramu; R. Vijaya; S. F. León-Luis; P. Babu; C. K. Jayasankar; V. Lavín; L. J. Dhareshwar

2011-01-01

139

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. This BEC can localize in the presence of disorder caused by Br- doping to form a Bose Glass. The BEC-Bose Glass (BEC-BG) transition can be carefully controlled by magnetic field, allowing us to sensitively

Weston, Ken

140

Microwave response near zero magnetic field in transition-metal-doped silicate glasses  

E-print Network

Microwave response near zero magnetic field in transition-metal-doped silicate glasses R. R- and iron-doped Na2O­CaO­MgO­SiO2 glasses with phase opposite to the normal Mn 2 and Fe 3 paramagnetic signals. The response can be described as magneto-induced microwave conductivity in the dielectric glass

Glebov, Leon

141

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

E-print Network

. It was observed that nucleation occurs at temperatures higher than 800 °C, when ions can diffuse into the glass1931 Magnetism of spinel microcrystals in a Cr3+ -doped cordierite glass : an E. S. R. study C+ clusters which grow, during various heat treatments, in a 0.8 % Cr2O3-doped cordierite glass. We found

Boyer, Edmond

142

Preparation of antibacterial silver-doped silica glass microspheres.  

PubMed

Various types of inorganic substances doped with silver ions have been developed as antibacterial materials, and some have already been commercialized. Colorless and chemically durable materials that slowly release silver ions are, however, still need to be developed. The present authors have previously shown that when a silica glass doped with silver and aluminium ions is prepared using the sol-gel method, the resultant product is colorless, chemically durable, and slowly releases silver ions into water over a long period. The doped silica glass takes a form of microspheres <1 microm in diameter, it is easily mixed with organic polymers, and the mixture can be formed into a thin film or fine fibers, etc. We report on the preparation of silver doped silica glass microspheres having a diameter =1 microm, using the sol-gel method. Initially, tetraethoxysilane was partially prehydrolyzed by water in ethanol, and then aluminium triisopropoxide was added to the solution to form Si-O-Al bonds. Finally, an ammonia solution containing silver nitrate was added to form silica microspheres doped with silver ion together with aluminium ions. The results show monodispersed microspheres 0.4-0.6 microm in diameter were obtained with nominal compositions of Si/Al/Ag = 1/0.01-0.03/0.003-0.03, with a molar ratio of Al/Ag = 1-3.3. The microspheres were colorless, showed a high chemical durability, and slowly released silver ions into water at 37 degrees C. Microspheres with the composition Si/Al/Ag = 1/0.01/0.01 showed excellent antibacterial activity against Escherichia coli. The minimum inhibitory concentration (MIC) of the microspheres was 400, which is less than the MIC value (800) of commercial antibacterial materials. PMID:12888996

Kawashita, Masakazu; Toda, Shogo; Kim, Hyun-Min; Kokubo, Tadashi; Masuda, Noriaki

2003-08-01

143

Luminescence characteristics of Li?CO?-K?CO?-H?BO? glasses co-doped with TiO?/MgO.  

PubMed

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

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

2013-12-01

144

Spectroscopic properties of -doped K-Sr-Al phosphate glasses  

NASA Astrophysics Data System (ADS)

Trivalent holmium-doped K-Sr-Al phosphate glasses (--SrO--) were prepared, and their spectroscopic properties have been evaluated using absorption, emission, and excitation measurements. The Judd-Ofelt theory has been used to derive spectral intensities of various absorption bands from measured absorption spectrum of 1.0 mol% -doped K-Sr-Al phosphate glass. The Judd-Ofelt intensity parameters (, ) have been determined of the order of , , and , which in turn used to derive radiative properties such as radiative transition probability, radiative lifetime, branching ratios, etc. for excited states of ions. The radiative lifetimes for the , , and levels of ions are found to be 169, 296, and 317 ?s, respectively. The stimulated emission cross-section for 2.05-?m emission was calculated by the McCumber theory and found to be . The wavelength-dependent gain coefficient with population inversion rate has been evaluated. The results obtained in the titled glasses are discussed systematically and compared with other -doped systems to assess the possibility for visible and infrared device applications.

Linganna, K.; Rathaiah, M.; Venkatramu, V.; Jayasankar, C. K.

2014-05-01

145

Optical properties of samarium doped zinc phosphate glasses  

NASA Astrophysics Data System (ADS)

Samarium doped zinc phosphate glasses having composition Sm2O3 (x)ZnO(60-x) P2O5 (40) (where x=0.1 0.5 mol%) were prepared by melt quenching method. The density of these glasses was measured by Archimedes method; the corresponding molar volumes have also been calculated. The values of density range from 3.34 to 3.87 gm/cm3 and those of molar volume range from 27.62 to 31.80 cm-3. The optical absorbance studies were carried out on these glasses to measure their energy band gaps. The absorption spectra of these glasses were recorded in UV-visible region. No sharp edges were found in the optical spectra, which verifies the amorphous nature of these glasses. The optical band gap energies for these glasses were found to be in the range of 2.89 4.20 eV. The refractive index and polarizability of oxide ion have been calculated by using Lorentz Lorentz relations. The values of refractive index range from 2.13 to 2.42 and those of polarizability of oxide ion range from 6.51×10-24 to 7.80×10-24 cm3.

Eraiah, B.; Bhat, Sudha G.

2007-04-01

146

Thermal and Optical Properties of Yb - and Nd -Doped Phosphate Glasses Determined by Thermal Lens Technique  

Microsoft Academic Search

In this work, we study the thermal and optical prop- erties of ion-doped phosphates glasses using the thermal lens (TL) technique. Three samples were characterized: Nd -doped Q-98; Nd -doped Q-100; and Yb -doped QX. We report multiwave- length TL measurements for a more accuracy determination of the fluorescence quantum efficiency and temperature coefficient of the optical path length change

Djalmir N. Messias; Carlos Jacinto; Maria Jose; V. Bell; Tomaz Catunda

2007-01-01

147

Differential scanning calorimetry investigations on Eu-doped fluorozirconate-based glass ceramics  

PubMed Central

The properties of Eu-doped fluorochlorozirconate (FCZ) glass ceramics upon thermal processing and the influence of Eu-doping on the formation of BaCl2 nanocrystals therein have been investigated. Differential scanning calorimetry indicates that higher Eu-doping shifts the crystallization peak of the nanocrystals in the glass to lower temperatures, while the glass transition temperature remains constant. The activation energy and the thermal stability parameters for the BaCl2 crystallization are determined. PMID:21286235

Paßlick, C.; Ahrens, B.; Henke, B.; Johnson, J. A.; Schweizer, S.

2010-01-01

148

Spectral analysis of thulium doped zinc-boro-silicate glass  

NASA Astrophysics Data System (ADS)

This paper reports on the results concerning the optical absorption and photoluminescence spectra of Tm 3+-doped zinc-boro-silicate (ZBS) glass. Absorption spectrum of this glass has revealed seven absorption bands in the wavelength region of 300-2000 nm. From the measured oscillator strengths of these absorption bands, three phenomenological Judd-Ofelt intensity ( ?2, ?4, ?6) parameters have been computed by the application of a least-squares fit analysis. These intensity characteristic factors have successfully been used in evaluating the radiative properties of the emission transitions of the rare earth ion (Tm 3+) in zinc borosilicate glass. The measured emission profile of this Tm 3+-glass, has displayed three emission bands such as 1D 2? 3H 4 (weak blue), 1G 4? 3H 6 (strong blue) and 1G 4? 3H 4 (weak red), when excited by 356 nm wavelength. Lifetime ( ?m) of the blue emission ( 1G 4? 3H 6) at 473 nm has been measured and compared with the radiative lifetime ( ?R) obtained based on the application of Judd-Ofelt theory. Non-radiative relaxation mechanisms have been attributed to the multiphonon-assisted relaxation on the basis of the high-energy phonon modes that could be found in the glass network.

Annapurna, K.; Das, Maumita; Buddhudu, S.

2007-01-01

149

Thermal, chemical and structural characteristics of erbium-doped sodium phosphate glasses  

Microsoft Academic Search

Thermal, chemical and structural characteristics of the erbium-doped sodium phosphate glasses with 1–6mol% Er2O3 were investigated. The glass transition temperature increase, but the thermal expansion coefficient and the dissolution rate of the glasses decrease with increasing Er2O3 content. X-ray photoelectron spectroscopy (XPS) and Fourier transformed infrared (FTIR) spectrometer were used to inspect the structural changes of the glasses. The doping

P. Y Shih

2004-01-01

150

Effect of Sm-, Gd-co-doping on structural modifications in aluminoborosilicate glasses under -irradiation  

E-print Network

) or borosilicate glasses (in France, England and United States). These nuclear waste glasses are often complex1 Effect of Sm-, Gd-co-doping on structural modifications in aluminoborosilicate glasses under glasses with different total rare earth content have been studied in order to examine the codoping effect

Paris-Sud XI, Université de

151

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 in a selenium- based glass-ceramic having a composition of 80GeSe2-20Ga2Se3+1000 ppm Er. The optical have never been reported in selenide glass matrices despite the fact that selenium-based glasses should

Boyer, Edmond

152

Highly efficient near-infrared quantum cutting in co-doped chalcohalide glasses  

E-print Network

. The glasses obtained were annealed at a temperature hal-00859852,version1-9Oct2013 #12;20 o C below the glassHighly efficient near-infrared quantum cutting in Ce3+ /Yb3+ co-doped chalcohalide glasses Bing Gao visible photon absorbed is realized from Ce3+ /Yb3+ codoped chalcohalide glasses. Excitation, emission

Boyer, Edmond

153

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

154

Surface silver-doping of biocompatible glass to induce antibacterial properties. Part I: Massive glass.  

PubMed

A glass belonging to the system SiO(2)-Al(2)O(3)-CaO-Na(2)O has been subjected to a patented ion-exchange treatment to induce surface antibacterial activity by doping with silver ions. Doped samples have been characterized by means of X-Ray diffraction (XRD), scanning electron microscopy (SEM) observation, energy dispersion spectrometry (EDS) analysis, in vitro bioactivity test, Ag(+) leaching test by graphite furnace atomic absorption spectroscopy (GFAAS) analyses, cytotoxicity tests by fibroblasts adhesion and proliferation, adsorption of IgA and IgG on to the material to evaluate its inflammatory property and antibacterial tests (cultures with Staphylococcus aureus and Escherichia coli). In vitro tests results demonstrated that the modified glass maintains the same biocompatibility of the untreated one and, moreover, it acquires an antimicrobial action against tested bacteria. This method can be selected to realize glass or glass-ceramic bone substitutes as well as coatings on bio-inert devices, providing safety against bacterial colonization thus reducing the risks of infections nearby the implant site. The present work is the carrying on of a previous research activity, concerning the application of an ion-exchange treatment on glasses belonging to the ternary system SiO(2)-CaO-Na(2)O. On the basis of previous results the glass composition was refined and the ion-exchange process was adapted to it, in order to tune the final material properties. The addition of Al(2)O(3) to the original glass system and the optimization of the ion-exchange conditions allowed a better control of the treatment, leading to an antibacterial material, without affecting both bioactivity and biocompatibility. PMID:18987954

Verné, E; Miola, M; Vitale Brovarone, C; Cannas, M; Gatti, S; Fucale, G; Maina, G; Massé, A; Di Nunzio, S

2009-03-01

155

Transmittance properties and TEM observation of metal doped glass by field-assisted ion exchange  

NASA Astrophysics Data System (ADS)

Metal (silver or copper) ions were doped into borosilicate glass using an electric field- assisted ion exchange method. The optical transmittance of the metal doped glass was measured to determine why the doped glass exhibited an excellent laser micro-machinability. The doped metal ions were found to have enhanced the optical absorption of the glass, especially in the ultraviolet range. This in turn facilitated the efficient absorption of incident laser irradiation, and hence improved laser machinability of the glass. The metal doped glass also exhibited some absorption in the visible range, leading to a slight yellow-brown coloration. Transmission electron microscope (TEM) observations indicated that the metal ions had penetrated the glass and therein formed nanometer-sized (~6 nm) fine particles. In an attempt to control the optical characteristics in the ultraviolet-visible range, metal doped glass was heat-treated following the ion exchange doping step. In the case of silver-doped glass with heat treatment at 723 K, silver nanoparticles aggregated locally yielding an inhomogeneous structure. The heat-treated samples had a high optical absorption in the ultraviolet range.

Matsusaka, Souta; Nomura, Taketsugu; Hidai, Hirofumi; Chiba, Akira; Morita, Noboru

2014-08-01

156

Ultrabroad emission from a bismuth doped chalcogenide glass.  

PubMed

We report emission from a bismuth doped chalcogenide glass which is flattened, has a full width at half maximum (FWHM) of 600 nm, peaks at 1300 nm and covers the entire telecommunications window. At cryogenic temperatures the FWHM reaches 850 nm. The quantum efficiency and lifetime were as high as 32% and 175 mus, respectively. We also report two new bismuth emission bands at 2000 and 2600 nm. Absorption bands at 680, 850, 1020 and 1180 nm were observed. The 1180 nm absorption band was previously unobserved. We suggest that the origin of the emission in Bi:GLS is Bi22- dimers. PMID:19997155

Hughes, Mark A; Akada, Takao; Suzuki, Takenobu; Ohishi, Yasutake; Hewak, Daniel W

2009-10-26

157

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

158

Optical properties of zincfluorophosphate glasses doped with Dy3+ ions  

NASA Astrophysics Data System (ADS)

Dy3+-doped zincfluorophosphate glasses with composition (in mol%) 44P2O5+17K2O+(30-x) ZnF2+9Al2O3+xDy2O3, x=0.01, 0.5, 1.0 and 2.0 have been prepared by melt quenching technique and were characterized through absorption, emission, excitation spectra and decay curves analysis. The energy levels obtained in the absorption spectrum have been analyzed by using free-ion Hamiltonian model. From the intensities of absorption spectra, Judd-Ofelt intensity parameters have been evaluated and in turn predicted the radiative properties such as radiative transition probability, radiative lifetime and branching ratios. The decay curves are found to be single exponential for lower concentrations (?0.1 mol%) and turns into non-exponential for higher concentrations. The non-exponential decay curves are well fitted to Inokuti-Hirayama model for S=6, which indicates that the energy transfer between the donor and the acceptor is of dipole-dipole nature. The fluorescence lifetime decreases from 0.82 ms to 0.45 ms with increase in Dy3+ ion concentration from 0.01 to 2.0 mol%. The results obtained for PKAZFDy glasses are compared and discussed with the other reported Dy3+: glasses. The chromaticity properties for different concentrations of PKAZFDy glass were calculated from emission spectra and analyzed with Commission International de I'Eclairage (CIE) color diagram.

Sreedhar, V. B.; Ramachari, D.; Jayasankar, C. K.

2013-01-01

159

Crystallizing hard-sphere glasses by doping with active particles.  

PubMed

Crystallization and vitrification are two different routes to form a solid. Normally these two processes suppress each other, with the glass transition preventing crystallization at high density (or low temperature). This is even true for systems of colloidal hard spheres, which are commonly used as building blocks for novel functional materials with potential applications, e.g. photonic crystals. By performing Brownian dynamics simulations of glassy systems consisting of mixtures of active and passive hard spheres, we show that the crystallization of such hard-sphere glasses can be dramatically promoted by doping the system with small amounts of active particles. Surprisingly, even hard-sphere glasses of packing fraction up to ? = 0.635 crystallize, which is around 0.5% below the random close packing at ? ? 0.64. Our results suggest a novel way of fabricating crystalline materials from (colloidal) glasses. This is particularly important for materials that get easily kinetically trapped in glassy states, and the crystal nucleation hardly occurs. PMID:25079244

Ni, Ran; Cohen Stuart, Martien A; Dijkstra, Marjolein; Bolhuis, Peter G

2014-09-21

160

Fullerene doped glasses Fucheng Lin, Sen Mao, Zhicong Meng, and Heping Zeng  

E-print Network

Fullerene doped glasses Fucheng Lin, Sen Mao, Zhicong Meng, and Heping Zeng Shanghai Institute 1994; accepted for publication 15 September 1994 Optical glasses doped with a fullerene mixture of C60/C70 were made in our lab. Three peaks, corresponding to C60, C70, and a modified fullerene possibly

Guo, Ting

161

Optical characteristics of silver-doped polarizing glass.  

PubMed

According to the theory of scattering and absorption of light, an anisotropic Ag colloid particle, which is small compared with the wavelength of the incident light, absorbs light differently in different directions. The underlying mechanism is regarded as electron plasma resonance. The optical anisotropy of a single Ag particle or of a group of the same particles has been analyzed. An equation for estimating the distribution of the particle shapes in space is proposed. Based on this equation and the work of other researchers, a program was designed to calculate the major principal transmittance and the minor principal transmittance of Ag-doped polarizing glass. The results show that the polarizing property of glass with particles with different aspect ratios is better than that of glass with identical particles. Also, the effective wavelength range is different if the particles' aspect ratios change, and this range tends to narrow as the parameter R (the rate of change of the aspect ratio) is increased. PMID:18026342

Wang, Dawei; Guo, Shiju; Ren, Haixia; Yin, Sheng

2002-06-15

162

Field-assisted solid state doping of glasses for optical materials  

NASA Astrophysics Data System (ADS)

Field-assisted solid-state ion-exchange (FASSIE) allows the doping of surface glass layers with multivalent ions which could not diffuse into the glass matrix by the usual thermal ion-exchange process in molten salt baths. This paper presents preliminary spectroscopic investigation of the diffusion of chromium in silicate glasses, with the aim at improving the procedures for the production of Cr-doped optical waveguides. Metallic chromium films deposited onto the glass substrates by the rf-sputtering technique were used as metal ions source. The environment of diffused chromium ions into the glass matrix was investigated by means of micro-Raman spectroscopy.

Quaranta, A.; Cattaruzza, E.; Gonella, F.; Peruzzo, G.; Giarola, M.; Mariotto, G.

2010-08-01

163

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

NASA Astrophysics Data System (ADS)

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.; Kolobov, A. V.; Mitrofanov, K. V.; Fons, P.; Tominaga, J.; Tamenori, Y.; Feuillet, G.

2014-05-01

164

Fluoride-modified electrical properties of lead borate glasses and electrochemically induced crystallization in the glassy state  

SciTech Connect

Lead fluoroborate glasses were prepared by the melt-quenching technique and characterized in terms of (micro)structural and electrical properties. The study was conducted on as prepared as well as temperature- and/or electric field-treated glass samples. The results show that, in the as-prepared glassy-state materials, electrical conductivity improved with increasing the PbF{sub 2} glass content. This result involves both an increase of the fluoride charge carrier density and, especially, a decrease of the activation energy from a glass structure expansion improving charge carrier mobility. Moreover, for the electric field-treated glass samples, surface crystallization was observed even below the glass transition temperature. As previously proposed in literature, and shown here, the occurrence of this phenomenon arose from an electrochemically induced redox reaction at the electrodes, followed by crystallite nucleation. Once nucleated, growth of {beta}-PbF{sub 2} crystallites, with the indication of incorporating reduced lead ions (Pb{sup +}), was both (micro)structurally and electrically detectable and analyzed. The overall crystallization-associated features observed here adapt well with the floppy-rigid model that has been proposed to further complete the original continuous-random-network model by Zachariasen for closely addressing not only glasses' structure but also crystallization mechanism. Finally, the crystallization-modified kinetic picture of the glasses' electrical properties, through application of polarization/depolarization measurements originally combined with impedance spectroscopy, was extensively explored.

M'Peko, Jean-Claude; Souza, Jose E. de; Rojas, Seila S.; Hernandes, Antonio C. [Grupo Crescimento de Cristais e Materiais Ceramicos (GCCMC), Instituto de Fisica de Sao Carlos (IFSC), Universidade de Sao Paulo - USP, C. Postal: 369, CEP: 13560-970 369 Sao Carlos, Sao Paulo (Brazil)

2008-02-15

165

Photoluminescence in Ga/Bi co-doped silica glass.  

PubMed

Bismuth-Gallium co-doped silica glass fiber preform was prepared from nano-porous silica xerogels using a conventional solution doping technique with a heterotrinuclear complex and subsequent sintering. Ga-connected optical Bismuth active center (BAC) was identified as the analogue of Al-connected BAC. Visible and infrared photoluminescence (PL) were investigated in a wide temperature range of 1.46 - 300 K. Based on the results of the continuous wave (CW) and time resolved (TR) spectroscopy we identify the centers emitting in the spectral region of 480 - 820 nm as Bi(+) ions. The near infrared (NIR) PL around 1100 nm consists of two bands. While the first one can be ascribed to the transition in Bi(+) ion, the second band is presumably associated to defects. We put in evidence the energy transfer (ET) between Bi(+) ions and the second NIR emitting center via quadrupole-quadrupole and dipole-quadrupole mechanisms of interactions. Finally, we propose the energy level diagram of Bi(+) ion interacting with this defect. PMID:24663907

Razdobreev, Igor; El Hamzaoui, Hicham; Arion, Vladimir B; Bouazaoui, Mohamed

2014-03-10

166

Improved omnidirectional reflectors in chalcogenide glass and polymer by using the silver doping technique.  

PubMed

We describe the fabrication and characterization of omnidirectional reflectors based on silver-doped chalcogenide glass and polymer. We deposited periodically alternating layers of thermally evaporated Ge33As12Se55 chalcogenide glass, sputtered silver, and spun-cast polyamide-imide polymer. The silver was subsequently dissolved into each adjacent chalcogenide glass layer, either by exposing the multilayer to visible light (photodoping) or by heating the sample. The resultant silver concentration within the chalcogenide glass layers is estimated to be ~20 at. %. Silver doping red-shifts the band edge of the glass, and produces an increase of ~0.3-0.4 in the refractive index. The glass retains good transparency in the near infrared after doping, and the technique enables the omnidirectional bandwidth to be increased from ~100 nm to ~200 nm in the 1550 nm wavelength region. PMID:19503507

Clement, Thomas; Ponnampalam, N; Nguyen, H T; Decorby, R G

2006-03-01

167

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

168

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

169

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

170

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

171

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

172

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

SciTech Connect

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

Egorova, O N; Semenov, S L; Vel'miskin, V V; Dianov, Evgenii M [Fiber Optics Research Center, Russian Academy of Sciences, Moscow (Russian Federation); Salganskii, M Yu; Yashkov, M V; Gur'yanov, Aleksei N [Institute of Chemistry of High-Purity Substances, Russian Academy of Sciences, Nizhnii Novgorod (Russian Federation)

2011-01-24

173

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

174

Quantum efficiency of Nd3+-doped phosphate glass under simulated sunlight  

NASA Astrophysics Data System (ADS)

Nd3+-doped P2O5-Al2O3-K2O-BaO (LHG-8) glasses were prepared and the internal quantum efficiency (QE) of near-infrared emission of the glasses were directly measured with a simulated sunlight source and an 800 nm laser. The stimulated emission cross section (?) and the radiative emission lifetime (?r) were also obtained by Judd-Ofelt analysis. The QE of Nd3+:LHG-8 under the simulated sunlight was as high as 60% at the Nd2O3 concentration of 0.05 mol%, and this value was higher than those of Nd3+-doped oxide glasses, such as borosilicate, silicate, and tellurite glasses. The ??r of LHG-8 was also higher than those of the other Nd3+-doped oxide glasses.

Nogata, Kohei; Suzuki, Takenobu; Ohishi, Yasutake

2013-09-01

175

Local-field approximation of homonuclear dipolar interactions in ?Li-NMR: density-matrix calculations and random-walk simulations tested by echo experiments on borate glasses.  

PubMed

NMR echo techniques have proven to be important to study dynamics in ion conductors and other solid materials. Using the spin-3/2 nucleus (7)Li as a probe, both the quadrupolar and the often neglected homonuclear dipolar interactions modulate the NMR frequency as the ion performs jump processes. Retaining only the local-field term of the many-body Hamiltonian, the impact of the dipolar interaction on various echo experiments was studied using spin dynamics calculations yielding products of dipolar and quadrupolar correlation functions. Using a simple stochastic model these functions were simulated with particular emphasis on the impact of ionic motions and on the conditions under which the dipolar and quadrupolar contributions factorize. The results of the computations and of the random-walk simulations are compared with experimental data obtained for various lithium borate and lithium borophosphate glasses. It is concluded that the local-field approximation is a useful means of treating the Li-Li dipole interactions and that the simple model that we introduce is capable of describing many experimentally observed features. Furthermore, because the dipolar and quadrupolar contributions essentially factorize, a selective determination of the corresponding correlation functions becomes possible. PMID:24593983

Storek, Michael; Jeffrey, Kenneth R; Böhmer, Roland

2014-01-01

176

The Fabrication and Uniformity Analysis of Low Temperature Ce3+ï¼YAG Doped Glass.  

E-print Network

??Using low-temperature (650â) Ce3+:YAG doped glass (LTCeYDG) phosphor layer instead of conventional Ce:YAG doped silicone phosphor layer applied to high-power phosphor-converted white-light-emitting diodes (PC-WLEDs) is… (more)

Chen, Ji-Hung

2012-01-01

177

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

178

Linear and non-linear optics and FTIR characteristics of borosilicate glasses doped with gadolinium ions  

NASA Astrophysics Data System (ADS)

Borosilicate glasses have been prepared using the high-temperature melt components of ingredients Gd2O3 doped borosilicate glasses. FTIR spectra were measured in the wavenumber range (4000-400 cm-1) to explore the state and influence of Gd3+ ions in the structure of the glasses. Data indicated that B2O3 is acting as dual network formers (BO3) and (BO4) structural units whereas the gadolinium ions playing the role of network modifier in these glasses. Optical transmission spectra were recorded in the range 190-2500 nm and different optical parameters such as the direct and the indirect optical band gap, Urbach energy, refractive index and optical dielectric constant, have been determined. The molar refraction, electronic polarizability and the optical basicity results have been determined using the measured glass refractive indices. Gadolinium-doped borosilicate glasses are found to be characterized by different optical parameters.

Marzouk, Samir Y.; Seoudi, Roshdi; Said, Doaa A.; Mabrouk, Mai S.

2013-10-01

179

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

180

New Er3+-doped phosphate glass for ion-exchanged waveguide amplifiers  

Microsoft Academic Search

A new Er(superscript 3+)-doped phosphate glass exhibiting an excellent durability in both boiling water and NaNO(subscript 3) molten salt is developed. The ion-exchange process of this glass is investigated by treating glass samples in a variety of salt baths with various exposure times. A planar waveguide with one mode at 1.54 micrometers and three modes at 632.8 nm is demonstrated.

Shibin Jiang; Tao Luo; Bor-Chyuan Hwang; Gualtiero Nunzi Conti; Michael J. Myers; Daniel L. Rhonehouse; Seppo Honkanen; Nasser Peyghambarian

1998-01-01

181

EXAFS study on metal cluster doped silica glass obtained by ion implantation procedures  

Microsoft Academic Search

Metal-doped glasses were prepared by double ion implantation (Ag+Cu and Au+Cu) in silica glass. X-ray absorption spectroscopy was used to study the different oxidation states of the dopant metals and the possible formation of metal or alloy clusters. We present an investigation on co-implanted silica glass at the Cu K, Ag K and Au LIII edges. The local atomic order

G. Battaglin; E. Cattaruzza; F D'Acapito; F. Gonella; P. Mazzoldi; S. Mobilio; F. Priolo

1998-01-01

182

New P2O5 and WO3 Doped Tellurite Glasses as Broadband Raman Gain Media  

Microsoft Academic Search

New tellurite-based glasses as broadband Raman gain media are developed to realize high performance fiber Raman amplifiers. These performances are achieved by WO3 and P2O5 doping in TeO2-BaO-SrO-Nb2O5 (TBSN) glass. The maximum gain coefficient obtained in the present study was ˜50 times that of silica glass for 532 nm excitation. The bandwidth (i.e., full width at half maximum) of these

Rajan Jose; Takenobu Suzuki; Yasutake Ohishi

2006-01-01

183

Heavy metal oxide glasses doped by rare earth ions for optoelectronics  

Microsoft Academic Search

Heavy metal oxide glasses in the system TeO2-PbO-WO3 doped by selected rare earth ions have been presented. The method of their preparation and physical properties were determined. Infrared luminescence of Er3+ and Tm3+ ions embedded in TeO2-PbO-WO3 glass hosts is reported for room and helium liquid temperatures. The substantial influence of energy transfer processes between the glass host and Er3+

Dominik Dorosz; Jan Wasylak

2005-01-01

184

Growth and characterization of pure and 1, 10 phenanthraline doped potassium penta borate (KB5) single crystals  

NASA Astrophysics Data System (ADS)

We concentrate on the low temperature slow solvent evaporation method and characterization of pure and 1, 10 phenanthraline doped KB5 and describe its potential as a non-linear optical material. The grown crystal has been subjected to single crystal X-ray diffraction analysis to identify the unit cell parameters and crystal system. The presence of carbon, hydrogen and oxygen content were confirmed by CHN analysis. The Kurtz's-Perry powder SHG efficiency was determined for both pure and 1,10 phenanthraline doped KB5 crystals as 1.6 and 2.2 times than that of pure KDP. Surface morphology of the pure and doped KB5 crystals has been found to be Scanning Electron Microscopic technique (SEM).

Prabha, K.; Babu, M. Ramesh; Sagayaraj, P.

2013-05-01

185

Green-white-yellow tunable luminescence from doped transparent glass ceramics containing nanocrystals  

NASA Astrophysics Data System (ADS)

, , and doped transparent ceramics containing nanocrystals were fabricated by a melt-quenching method and subsequent heating. Tetragonal phase spheres with 20 nm size are homogeneously precipitated among a borosilicate glass matrix. The photoluminescence spectrum of single doped transparent ceramics shows white light emission under 382 nm UV excitation. The emission color of co-doped transparent glass ceramics is tuned from green to white through energy transfer from to , and the emission color of co-doped transparent ceramics is tuned from white to yellow through energy transfer from to . CIE chromaticity and color temperature measurements show that the resulting transparent glass ceramics may be a candidate as a warm-white LED material pumped by a UV InGaN chip.

Wang, X. F.; Yan, X. H.; Xuan, Y.; Zheng, J.; He, W. Y.

2013-10-01

186

Electron transport studies in single transition metal ions doped borophosphate glasses  

NASA Astrophysics Data System (ADS)

Three series of boro-phosphate glasses doped with single transition metal ions, Cuo, Fe2O3 and CoO have been prepared by melt quenching method and investigated for room temperature density and dc electrical conductivity in the temperature range from 325 to 600K. The density increased with increasing transition metal ions concentration in all the three series. The measured conductivities were in the order of 10-7, 10-6 and 10-3 to 10-6 ?-1m-1 for CoO, CuO and Fe2O3 doped glasses respectively. At all temperatures of interest, the conductivity of Fe2O3 doped glasses was higher than that measured in the other two series of glasses. The conductivity increased with increasing contents of CuO and Fe2O3 in their respective series of glasses. Whereas the conductivity decreased with increasing CoO content in CoO doped glasses. In general, conductivity increased with increasing temperature in all the series and that has been analyzed in view of Mott's small polaron hopping (SPH) model and thereby high temperature activation energies have been determined. Various physical and polaron hopping related parameters such as molar volume, polaron hopping distance, radius, band width etc., have been determined and discussed. It is for the first time that the borophasphate glasses in the present compositions are studied for electron transport properties and subjected to thorough analysis.

Vijaya kumar, B.; Sankarappa, T.; Santoshkumar; Veena, S. S.

2009-07-01

187

A final report on hydrothermal testing of sup 99 Tc-doped glass waste form and waste package components  

Microsoft Academic Search

This document reports the results of four experiments using borosilicate glass doped with the key radionuclide ⁹⁹Technicium. The experiments were performed in Dickson rocking autoclaves at 200°C, 30MPa pressure for 3 months. Starting materials consisted of the doped glass (+ undoped borosilicate glass){center dot} in GR-3 groundwater. To simulate various possible interactions among waste package components, the glass-groundwater starting materials

J. A. Schramke; L. E. Thomas; S. G. McKinley; S. A. Simonson; D. G. Coles; Westinghouse Hanford Co; WA Richland

1984-01-01

188

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

NASA Astrophysics Data System (ADS)

We report on the design of an electric tube furnace that can be used for the fabrication of doped glass microsphere lasers. The tube furnace has a short hot zone of length 133 mm and is based on a quartz tube design. Doped laser glass particles, specifically Er:Yb phosphate glass (IOG-2), of ˜1 ?m diameter are blown into the furnace using a 60 ml syringe and microspheres ranging in size from 10 to 400 ?m are collected at the output of the tube furnace in a Petri dish. The furnace operates at a wall temperature of ˜900 °C and is capable of making microspheres from glasses with glass transition temperatures of at least 375 °C. High quality (Q ˜105) whispering gallery modes have been excited within the microspheres by optically pumping at 978 nm via a tapered optical fiber.

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

2010-07-01

189

Nanodiamond in tellurite glass Part II: practical nanodiamond-doped fibers  

E-print Network

Tellurite glass fibers with embedded nanodiamond are attractive materials for quantum photonics applications. Reducing the loss of these fibers in the 600-800 nm wavelength range of nanodiamond fluorescence is essential to exploit the unique properties of nanodiamond in the new hybrid material. The first part of this study reported the origin of loss in nanodiamond-doped glass and impact of glass fabrication conditions. Here, we report the fabrication of nanodiamond-doped tellurite fibers with significantly reduced loss in the visible through further understanding of the impact of glass fabrication conditions on the interaction of the glass melt with the embedded nanodiamond. We fabricated tellurite fibers containing nanodiamond in concentrations up to 0.7 ppm-weight, while reducing the loss by more than an order of magnitude down to 10 dB/m at 600-800 nm.

Ruan, Yinlan; Johnson, Brett C; Ohshima, Takeshi; Greentree, Andrew D; Gibson, Brant C; Monro, Tanya M; Ebendorff-Heidepriem, Heike

2014-01-01

190

Fluorescence properties and electron paramagnetic resonance studies of ?-irradiated Sm3+-doped oxyfluoroborate glasses  

NASA Astrophysics Data System (ADS)

The permanent photoinduced valence manipulation of samarium doped oxyfluoroborate glasses as a function of ?-ray irradiation has been investigated using a steady-state fluorescence and electron paramagnetic resonance techniques. An increase in SrF2 content in the glass led to the red shift of the peaks in as prepared glass, while in irradiated glasses this led to the decrease in defect formation as well as increase in photoreduction of Sm3+ to Sm2+ ion. The energy transfer mechanism of induced permanent photoreduction of Sm3+ to Sm2+ ions in oxyfluoroborate glasses has been discussed. The decay analysis shows exponential behavior before irradiation and non-exponential behavior after irradiation. The energy transfer in irradiated glasses increases with the increase in SrF2 content in the glass and also with the irradiation dose.

Babu, B. Hari; Ravi Kanth Kumar, V. V.

2012-11-01

191

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

192

Recrystallisation of Kaolinite and Iron-Doped Kaolinite Glasses.  

National Technical Information Service (NTIS)

The glasses were crystallised at various temperatures from 1000 to 1465 degrees. While the pure kaolinite glasses crystallised to form a 'mullite-like' structure and cristobalite above 1260 degrees, iron impurity facilitated the recrystallisation at lower...

D. N. Sitharamarao, J. F. Duncan, M. F. Coleman

1971-01-01

193

Structural modification in Er-Yb doped zinc phosphate glasses with megahertz repetition rate femtosecond pulses  

NASA Astrophysics Data System (ADS)

Focused femtosecond laser pulses from a 1 MHz fiber laser were used to create modifications in Er- Yb doped zinc phosphate glass. Two glasses with similar phosphate glass networks but different network modifiers were investigated. To understand the resulting changes caused by the femtosecond laser pulses various characterization techniques were employed: glass structural changes were investigated with confocal Raman spectroscopy, defect generation as well as local Er and Yb environment were investigated with confocal fluorescence spectroscopy, and elemental segregation resulting from heat accumulation effects was ascertained by scanning electron microscopy.

Troy, Neil; Fletcher, Luke B.; Reis, Signo T.; Brow, Richard K.; Huang, Huan; Yang, Lihmei; Liu, Jian; Krol, Denise M.

2012-01-01

194

Intense red photoluminescence from Mn2+-doped (Na+; Zn2+) sulfophosphate glasses and glass ceramics as LED converters.  

PubMed

We report on intense red fluorescence from Mn(2+)-doped sulfophosphate glasses and glass ceramics of the type ZnO-Na(2)O-SO(3)-P(2)O(5). As a hypothesis, controlled internal crystallization of as-melted glasses is achieved on the basis of thermally-induced bimodal separation of an SO(3)-rich phase. Crystal formation is then confined to the relict structure of phase separation. The whole synthesis procedure is performed in air at glasses, increasing MnO content results in decreasing network polymerization. Stable glasses and continuously increasing emission intensity are observed for relatively high dopant concentration of up to 3 mol.%. Recrystallization of the glass results in strongly increasing emission intensity. Dynamic emission spectroscopy reveals only on type of emission centers in the glassy material, whereas three different centers are observed in the glass ceramic. These are attributed to octahedrally coordinated Mn(2+) in the residual glass phase and in crystalline phosphate and sulfate lattices, respectively. Relatively low crystal field strength results in almost ideal red emission, peaking around 625 nm. Excitation bands lie in the blue-to-green spectral range and exhibit strong overlap. The optimum excitation range matches the emission properties of GaN- and InGaN-based light emitting devices. PMID:20174083

Da, Ning; Peng, Mingying; Krolikowski, Sebastian; Wondraczek, Lothar

2010-02-01

195

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

196

Third-order nonlinearity of Er3+-doped lead phosphate glass  

SciTech Connect

The third-order optical susceptibility and dispersion of the linear refractive index of Er3+-doped lead phosphate glass were measured in the wavelength range between 400 and 1940 nm by using the spectrally resolved femtosecond Maker fringes technique. The nonlinear refractive index obtained from the third-order susceptibility was found to be five times higher than that of silica, indicating that Er3+-doped lead phosphate glass is a potential candidate to be used as the base component for the fabrication of photonic devices. For comparison purposes, the Z-scan technique was also employed to obtain the values of the nonlinear refractive index of E-doped lead phosphate glass at several wavelengths, and the values obtained using the two techniques agree to within 15%.

Santos, C. C. [Universidade Federal do Ceara, Ceara, Brazil; Guedes Da Silva, Ilde [ORNL; Siqueira, J. P. [Instituto de Física de São Carlos, Universidade de São Paulo, Brazil; Misoguti, L. [Instituto de Física de São Carlos, Universidade de São Paulo, Brazil; Zilio, S. C. [Instituto de Física de São Carlos, Universidade de São Paulo, Brazil; Boatner, Lynn A [ORNL

2010-01-01

197

Application to Temperature Sensor Based on Green Up-Conversion of Er3+ Doped Silicate Glass  

PubMed Central

The green up-conversion emissions centered at the wavelengths of about 534nm and 549nm of the Er3+ doped silicate glass were recorded, using a 978 nm semiconductor laser diode (LD) as an excitation source. The fluorescence intensity ratio (FIR) of the green up-conversion emissions at about 534nm and 549nm in the Er3+ doped silicate glass was studied as a function of temperature over the temperature range of 296K-673K. The maximum sensitivity and the temperature resolution derived from the FIR of the green up-conversion emissions are approximately 0.0023K-1 and 0.8K, respectively. It is demonstrated that the prototype optical temperature sensor based on the FIR technique from the green up-conversion emissions in the Er3+ doped silicate glass could play a major role in temperature measurement.

Li, Chengren; Dong, Bin; Ming, Chengguo; Lei, Mingkai

2007-01-01

198

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

199

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

NASA Astrophysics Data System (ADS)

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.

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

2011-12-01

200

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

PubMed Central

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. PMID:22275772

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

2011-01-01

201

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

202

Spatial and temporal observation of energy transfer processes in Pr-doped phosphate glasses  

NASA Astrophysics Data System (ADS)

A spatially resolved microluminescence technique was used to measure the spatial distribution of emitted light and photon propagation into two different Pr3+ doped phosphate glasses. The photon diffusion length for specific wavelengths was measured. It was found that excited state re-absorption plays a crucial role in the propagation. Our results suggest that this microluminescence technique can be applied in the investigation of energy transfer processes in rare-earth doped systems.

Martins, V. M.; Azevedo, G. A.; Andrade, A. A.; Messias, D. N.; do Monte, A. F. G.; Dantas, N. O.; Pilla, V.; Catunda, T.; Braud, A.; Moncorgé, R.

2014-11-01

203

Interactions of gamma rays with tungsten-doped lead phosphate glasses  

Microsoft Academic Search

Undoped lead phosphate glass of the composition PbO 50 mol%, P2O5 50 mol% together with samples of the same ratio doped with various WO3 contents were prepared. UV–Visible spectroscopic studies were measured out in the range 200–1100 nm before and after successive\\u000a gamma irradiation. Infrared and Raman spectroscopic measurements were carried out for the undoped and WO3-doped samples. All the prepared samples are

Fatma Hatem ElBatal; Samir Yousef Marzouk

2009-01-01

204

Sm3+-doped germanate glass channel waveguide as light source for minimally invasive photodynamic therapy surgery.  

PubMed

In Sm(3+)-doped K(+)-Na(+) ion-exchanged aluminum germanate (NMAG) glass channel waveguide, a clear and compact red amplified spontaneous emission (ASE) trace is observed under the excitation of a 488nm Ar(+) laser. 78% photons of ASE fluorescence in visible region are demonstrated to be located in 600-730nm wavelength range. High-directivity and high-brightness ASE fluorescence of Sm(3+)-doped NMAG glass channel waveguide, which matches the excitation band of most photosensitizers (PS) currently used in photodynamic therapy (PDT) or clinical trials, has promising potential application as an excitation light source for PDT treatment. PMID:22274434

Chen, B J; Shen, L F; Pun, E Y B; Lin, H

2012-01-16

205

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

206

Effects of alkali ions on thermal stability and spectroscopic properties of Er 3+-doped gallogermanate glasses  

NASA Astrophysics Data System (ADS)

Since information transportation capacity of optical communication network increases rapidly, new optical materials are always demanded with gain bandwidth desirably much broader than traditional erbium-doped silica fiber amplifier (EDFA). We show here in this paper the erbium-doped gallogermanate glasses with a full-width at half-maximum (FWHM) more than 50 nm. Incorporation of alkali ions such as Li +, Na +, K + into the system can on the one hand improve the thermal stability of the glasses, and on the other hand enhance the emission at 1.5 ?m due to the 4I 13/2? 4I 15/2 transition of Er 3+ and suppress the upconversion process at the same time. This particularly works best for the case of K + inclusion. This work might give a general idea on controlling the Er 3+ luminescence by simply adjusting the glass component and find a potential laser glass applicable to developing new broadband fiber amplifier.

Shi, D. M.; Zhao, Y. G.; Wang, X. F.; Liao, G. H.; Zhao, C.; Peng, M. Y.; Zhang, Q. Y.

2011-02-01

207

Tunable white luminescence and energy transfer in novel Cu?, Sm³? co-doped borosilicate glasses for W-LEDs.  

PubMed

The luminescent properties of novel Cu?, Sm³? single- and co-doped borosilicate glasses were systematically investigated by absorption, excitation, emission spectra and decay curves. Cu? single-doped glasses emit broad luminescence band covering all the visible range. And their peaks shift to blue with decreasing excitation wavelength from 330 to 280 nm. Cu?, Sm³? co-doped samples generate the varied hues from blue white to pure white and eventually to yellow white due to an efficient energy transfer from Cu? to Sm³?. Our research indicates the potential application of Cu?, Sm³? co-doped borosilicate glasses as converting phosphors for white LEDs pumped by UV LED chips. PMID:23388801

Wei, RongFei; Ma, ChongGeng; Wei, YunLe; Gao, JiaYu; Guo, Hai

2012-12-31

208

Photoluminescence properties of Dy3+-doped oxyfluoride germanosilicate optical glass-ceramics  

NASA Astrophysics Data System (ADS)

Dy3+-doped oxyfluoride germanosilicate glass and glass-ceramics were fabricated using a GeO2-SiO2-Al2O3-B2O3-BaO-BaF-Dy2O3 system. Differential thermal analysis, X-ray diffraction, and photoluminescence spectra were carried out to study the effects of the concentration of F- ions and the heat treatment on structure and optical properties of the samples. The results showed that the glass has the strongest luminescence intensity when BaF2 totally substitutes BaO. Moreover, Ba3AlF9 nanocrystal was formed in the glass matrix after being heat treated at 560-600 °C for 2-8 h. The glass after heat treatment had stronger intensity of luminescence than the precursor glass. The intensity of luminescence reaches an optimum when it was heat treated at 580 °C for 4 h.

He, Yunlong; Zhao, Gaoling; Qin, Huijun; Wang, Jianxun; Han, Gaorong

2014-03-01

209

Luminescence of trivalent samarium ions in silver and tin co-doped aluminophosphate glass  

NASA Astrophysics Data System (ADS)

This work presents the spectroscopic properties of trivalent samarium ions in a melt-quenched aluminophosphate glass containing silver and tin. Addition of 4 mol% of each Ag 2O and SnO into the glass system with 2 mol% Sm 2O 3 results in Sm 3+ ions luminescence under non-resonant UV excitation owing to energy transfer from single silver ions and/or twofold-coordinated Sn centers. Assessment of luminescence spectra and decay dynamics suggest the energy transfer mechanism to be essentially of the resonant radiative type. Moreover, a connection between the luminescent and structural properties of the rare-earth doped glass system was demonstrated. Raman spectroscopy characterization revealed that no significant variation in the glass matrix is induced by Sm 3+ doping at the concentration employed. A comparison was made with a structural study performed on the Eu 3+ doped system (containing 2 mol% Eu 2O 3 along with 4 mol% of each Ag 2O and SnO) where the radiative energy transfer mechanism was previously established. The data appears consistent regarding the lack of variation in glass structure upon the Eu 3+ and Sm 3+ doping in connection with the dominance of the radiative transfer in the matrix. Thermal treatment of the material leads to precipitation of Ag nanoparticles of a broad size range inside the dielectric as observed by transmission electron microspcopy. Assessment of 4G 5/2 excited state decay in Sm 3+ ions shows no influence from the silver particles.

Jiménez, José A.; Lysenko, Sergiy; Liu, Huimin; Sendova, Mariana

2011-06-01

210

Highly efficient reddish orange emission in Mn2+/Eu3+ co-doped phosphate glasses for greenhouse  

NASA Astrophysics Data System (ADS)

A series of phosphate glasses doped with Mn2+/Eu3+ ions were prepared by high temperature melting method to explore reddish orange luminescent materials for greenhouse. The absorption, emission, and excitation spectra of the samples were studied in detail. A wide excitation band at 300-550 nm in the Mn2+/Eu3+ co-doped phosphate glasses was observed. Under the illumination of sunlight, the Mn2+/Eu3+ co-doped phosphate glasses can emit strong red emission. Our materials will be helpful to improve the utilization of solar for glass greenhouses.

Ming, Chengguo; Song, Feng; Ren, Xiaobin; An, Liqun

2013-07-01

211

Quantum efficiencies of near-infrared emission from Ni 2+-doped glass-ceramics  

Microsoft Academic Search

A systematic method to evaluate potentials of Ni2+-doped transparent glass-ceramics as a new broadband optical gain media is presented. At first, near-infrared emission of various ceramics were investigated to explore the suitable crystalline phase to be grown in the glass-ceramics. The quantum efficiency of Ni2+ near-infrared emission estimated by the Struck–Fonger analysis was higher than 95% for spinel-type structure gallate

Takenobu Suzuki; Yusuke Arai; Yasutake Ohishi

2008-01-01

212

Study on Optical Properties and Structure of Sm 2O 3 Doped Boron-Aluminosilicate Glass  

Microsoft Academic Search

Sm3+ doped B2O3-Al2O3-SiO2 glasses were prepared by high temperature solid-state method. The absorption spectrum, excitation spectrum, emission spectrum and the effect on concentrations of Sm3+ were investigated at room temperature. The results indicated that, under the excitation of 472 nm, the glass gane visible (VIS) and near infra-red (NIR) emissions at 596, 641, 561, 1075, 1118 and 1177 nm, respectively.

Ni Yaru; Lu Chunhua; Zhang Yan; Zhang Qitu; Xu Zhongzi

2007-01-01

213

Spectroluminescence properties of potassium-aluminosilicophosphate glasses doped with rare-earth ions  

NASA Astrophysics Data System (ADS)

This paper discusses the results of a study of the spectroluminescence properties of potassium-aluminosilicophosphate glasses (PASPGs) doped with ions of the 4f elements. The matrix composition and the dopant concentration in the synthesized glasses are described. The general response of the absorption and luminescence spectra of trivalent Pr, Nd, Sm, and Eu ions in PASPGs are presented for the spectral regions in which the lasing transitions of the corresponding ions are located.

Batyaev, I. M.; Tinus, A. M.

2004-12-01

214

Spectroscopic properties and energy transfer parameters of Er3+- doped fluorozirconate and oxyfluoroaluminate glasses  

NASA Astrophysics Data System (ADS)

Er3+- doped fluorozirconate (ZrF4-BaF2-YF3-AlF3) and oxyfluoroaluminate glasses are successfully prepared here. These glasses exhibit significant superiority compared with traditional fluorozirconate glass (ZrF4-BaF2-LaF3-AlF3-NaF) because of their higher temperature of glass transition and better resistance to water corrosion. Judd-Ofelt (J-O) intensity parameters are evaluated and used to compute the radiative properties based on the VIS-NIR absorption spectra. Broad emission bands located at 1535 and 2708 nm are observed, and large calculated emission sections are obtained. The intensity of 2708 nm emission closely relates to the phonon energy of host glass. A lower phonon energy leads to a more intensive 2708 nm emission. The energy transfer processes of Er3+ ions are discussed and lifetime of Er3+: 4I13/2 is measured. It is the first time to observe that a longer lifetime of the 4I13/2 level leads to a less intensive 1535 nm emission, because the lifetime is long enough to generate excited state absorption (ESA) and energy transfer (ET) processes. These results indicate that the novel glasses possess better chemical and thermal properties as well as excellent optical properties compared with ZBLAN glass. These Er3+- doped ZBYA and oxyfluoroaluminate glasses have potential applications as laser materials.

Huang, Feifei; Liu, Xueqiang; Hu, Lili; Chen, Danping

2014-05-01

215

Femtosecond and coherent effects in bulk CdSe and CdSexS1-x doped glasses  

E-print Network

1711 Femtosecond and coherent effects in bulk CdSe and CdSexS1-x doped glasses N. Peyghambarian. Abstract. 2014 Bulk CdSe and microcrystallites of CdSexS1-x embedded in a glass matrix are studied using-1715 DÃ?CEMBRE 1987, PAGE 1711 Classification Physics Abstracts 42.65 - 42.70G Glasses doped with Cd

Boyer, Edmond

216

Thermal analysis, spectral characterization and refractive index studies of lithium doped PbO-ZnO-B{sub 2}O{sub 3} glass  

SciTech Connect

Lithium containing lead zinc borate glasseshave been prepared by melt quenching technique. X-ray diffraction reveals the amorphous nature of the glass. Differential scanning calorimeter (DSC) study was carried out in the temperature range RT to 600 deg. C temperature and found glass transition temperature of these glasses decreases with increase in inter substitution of Pb and Zn lithium content. PZB glasses are stable, IR spectra of these glasses show characteristics band originating from borate groups namely [BO{sub 3}] [BO{sub 4}]and B-O-B stretching vibrations respectively, and found that structure is not affected with effect of lithium content. Refractive index of these glasses are in the range of 1.47 with increasing lithium content refractive index decreases indicating decrease in scattering of light.

Rajaramakrishna, R.; Lakshmikantha, R.; Anavekar, R. V. [Department of Physics, Bangalore University, Jnanabarthi campus, Bangalore - 560056 (India); Department of Physics, K.L.E.Society's S. N. College, Bangalore - 560 010 (India); Department of Physics, Bangalore University, Jnanabarthi campus, Bangalore - 560056 (India)

2012-06-05

217

Er{sup 3+}-doped soda-lime glasses and planar waveguide devices  

SciTech Connect

The fabrication and optical performance of planar optical waveguide amplifiers, comprising of deposited Er{sup 3+}-doped soda-lime glass cores on silicon optical bench platforms is documented in this paper. The results are encouraging for practical device applications. A laser device has also been characterized. Its modest performance highlights some of the differences between amplifiers and lasers.

Bruce, A.J.; Grodkiewicz, W.H.; Shmulovich, J. [AT& T Bell Labs., Murray Hill, NJ (United States)] [and others

1996-12-31

218

Optical phase conjugation in Rhodamine6G doped boric acid glass  

Microsoft Academic Search

Optical phase conjugation has been demonstrated in Rhodamine-6G doped boric acid glass using a cw argon ion laser. The dependence of the phase conjugated signal on the intensity and wavelength of the pump beam is studied The role of amplitude and phase grating contributions to the phase conjugated signal is discussed.

G. Ravindra Kumar; Bhanu P. Singh; K. K. Sharma

1989-01-01

219

Fabrication of Rare Earth-Doped Transparent Glass Ceramic Optical Fibers by Modified Chemical Vapor Deposition  

E-print Network

Fabrication of Rare Earth-Doped Transparent Glass Ceramic Optical Fibers by Modified Chemical Vapor weaken the fibers, and it introduces certain 2 #12;complexicities in the global fabrication process report deals with silica-based TGC fiber preforms prepared by the well-known MCVD (modified chemical

Paris-Sud XI, Université de

220

New Er3+-doped phosphate glass for ion-exchanged waveguide amplifiers  

NASA Astrophysics Data System (ADS)

A new Er(superscript 3+)-doped phosphate glass exhibiting an excellent durability in both boiling water and NaNO(subscript 3) molten salt is developed. The ion-exchange process of this glass is investigated by treating glass samples in a variety of salt baths with various exposure times. A planar waveguide with one mode at 1.54 micrometers and three modes at 632.8 nm is demonstrated. The spectral properties of Er(superscript 3+) in this glass are characterized by measuring absorption and emission spectra and fluorescence lifetimes. The emission cross section of Er(superscript 3+) in this glass is calculated to be 0.76 X 10(superscript 20) cm(superscript 2) using McCumber theory.

Jiang, Shibin; Luo, Tao; Hwang, Bor-Chyuan; Nunzi Conti, Gualtiero; Myers, Michael J.; Rhonehouse, Daniel L.; Honkanen, Seppo; Peyghambarian, Nasser

1998-12-01

221

Photon avalanche upconversion in Ho3+-Yb3+ co-doped transparent oxyfluoride glass-ceramics  

NASA Astrophysics Data System (ADS)

The Ho3+-Yb3+ co-doped transparent glass and glass-ceramics containing CaF2 nanocrystals have been prepared. Differential thermal analysis and X-ray diffraction measurements have been made to characterize thermal properties of glass and structural changes in glass-ceramics, respectively. Photon avalanche upconversion has been achieved by exciting the samples at 745 nm at room temperature. An intense green and a weak red upconverted emissions corresponding to the 5S2:5F4 ? 5I8 and 5F5 ? 5I8 transitions, respectively, have been observed. The upconversion intensity has been found to increase with the increase in the size of the fluoride nanocrystals in glass-ceramics. Experimental evidences confirm that the mechanism of upconversion is photon avalanche.

Babu, P.; Martín, I. R.; Venkata Krishnaiah, K.; Seo, Hyo Jin; Venkatramu, V.; Jayasankar, C. K.; Lavín, V.

2014-04-01

222

Spectroscopic properties and external quantum yield of Sm3+ doped germanotellurite glasses  

NASA Astrophysics Data System (ADS)

Sm3+ doped germanotellurite glasses (NZPGT) with maximum phonon energy of 793 cm-1 have been prepared and characterized. Judd-Ofelt parameters ?t (t=2, 4, 6) have been calculated to be 3.52×10-20, 4.70×10-20 and 1.90×10-20 cm2, respectively. Large value of ?2 indicates a high asymmetry and covalent environment around Sm3+ in the glass system. The maximum stimulated emission cross-section of the dominant transition 4G5/2?6H9/2 peaking at 645.0 nm was derived to be 10.00×10-22 cm2, predicting that the red fluorescence emission can be efficiently extracted from the optical glasses. The internal quantum efficiency and external quantum yield of 0.4 wt% Sm2O3 doped NZPGT glasses were deduced to be 82.5% and 6.0%, respectively. The results demonstrate that Sm3+ doped NZPGT glasses are a potential candidate for developing tunable visible lasers, compact light sources and solid-state display devices.

Wang, F.; Chen, B. J.; Lin, H.; Pun, E. Y. B.

2014-11-01

223

Second-harmonic generation of thermally poled silver doped sodo-borophosphate glasses  

NASA Astrophysics Data System (ADS)

Sodium niobium borophosphate glass, with a composition of 0.58(0.95NaPO3+0.05Na2B4O7)+0.42Nb2O5, has been doped with monovalent silver ions. Second harmonic generation (SHG) has been obtained from the poling treatment of this sample. The second order nonlinearity from the anode side was estimated from an analysis of transmitted polarized Maker-fringe patterns. Thanks to the original Maker fringe simulations, a value of 3 pm/V is obtained with the silver doped glass that unambiguously scales an enhancement of ˜35% with respect to the nondoped glass susceptibility. For both glasses, the nonlinear layer is found to be sodium-depleted up to 4 ?m inside the anode, in accordance with quantitative energy dispersive x-ray spectroscopy characterizations. This comparative study indicates complex space-charge-migration processes during the poling treatment. The relative enhancement of the SHG signal of the silver doped glass is correlated with the increase in its linear susceptibility.

Fargin, Evelyne; Soulié, Jérémy; Cardinal, Thierry; Lahaye, Michel; Rodriguez, Vincent; Couzi, Michel; Adamietz, Frédéric

2009-01-01

224

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

NASA Astrophysics Data System (ADS)

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

Augustyn, El?bieta; ?elechower, Micha?; Stró?, Danuta; Chrapo?ski, Jacek

2012-04-01

225

Theoretical studies on mid-infrared amplification in Ho3+-doped chalcogenide glass fibers  

NASA Astrophysics Data System (ADS)

This paper investigated the MIR emission of Ho3+-doped Ge20Ga5Sb10S65 chalcogenide glasses upon excitation of 900 nm laser diode. The spontaneous emission probability, absorption cross-section, and emission cross-section were calculated using the Judd-Ofelt theory and the Fuchbauer-Ladenburg equation. Theoretical studies of the Ho3+-doped chalcogenide glass fiber amplifier operating in the MIR wavelength range, specifically around the 2.86 ?m wavelength, were performed based on the rate and light propagation equations. The results indicate that the chalcogenide glass fiber presented a larger signal MIR gain and wider MIR gain spectrum. The maximum signal gain was 36 dB and the gain width was 20 dB.

Wei, Shulin; Xu, Yinsheng; Dai, Shixun; Zhou, Yaxun; Lin, Changgui; Zhang, Peiqing

2013-05-01

226

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

227

Enhanced broadband near-infrared luminescence and its origin in Yb/Bi co-doped borophosphate glasses and fibers  

NASA Astrophysics Data System (ADS)

Yb/Bi co-doped borophosphate glasses and fibers were prepared. The effect of Yb3+ on the near-infrared (NIR) luminescent properties and the mechanism of luminescence of Bi-ions were investigated. Under 976 nm laser diode (LD) excitation, the NIR emission intensity of the glass with 8 mol% Yb2O3 co-doped glass is ~37 times stronger than that of Bi singly-doped glass. The fluorescence lifetime increases by ~7 times with 5 mol% Yb2O3 co-doped glass. The energy transfer efficiency is ~59.1%. It is also suggested that the broadband NIR luminescence pumped by 808 nm and 976 nm LDs derives from Bi+ and Bi2+, respectively.

Sheng, Qiuchun; Wang, Xiaolin; Chen, Danping

2014-07-01

228

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

229

Biocompatibility and antibacterial effect of silver doped 3D-glass-ceramic scaffolds for bone grafting.  

PubMed

A 3D-glass-ceramic scaffold for bone tissue engineering with an interconnected macroporous network of pores was doped with silver ions in order to confer antibacterial properties. For this purpose, silver ions were selectively added to the scaffold surfaces through ion-exchange using an aqueous silver nitrate solution. The silver-doped scaffolds were characterized by means of leaching, in vitro antibacterial, and citotoxicity tests. In particular, the silver effect was examined through a broth dilution test in order to evaluate the proliferation of bacteria by counting the colonies forming units. Moreover, cytotoxicity tests were carried out to understand the effect of silver-containing scaffolds on cell adhesion, proliferation, and vitality. For all tests a comparison between silver-doped scaffold and silver-doped scaffold dry sterilized was performed. PMID:20207775

Balagna, Cristina; Vitale-Brovarone, Chiara; Miola, Marta; Verné, Enrica; Canuto, Rosa Angela; Saracino, Silvia; Muzio, Giuliana; Fucale, Giacomo; Maina, Giovanni

2011-02-01

230

Transition-metal-doped chalcogenide glasses for broadband near-infrared sources  

NASA Astrophysics Data System (ADS)

In this paper we report the spectroscopic data for samples of 0.031% iron, 0.017% nickel, 0.01% chromium and 0.017% cobalt (molar) doped gallium lanthanum sulphide (GLS) glass. Photoluminescence (PL) with a full width half maximum (FWHM) of around 500 nm and peaking between 1120 nm and 1460 nm is observed when excited using wavelengths of 850 nm and 1064 nm. The emission lifetime for nickel-doped GLS at 300 K was measured to be 40 ?s. Photoluminescence excitation (PLE) peaks for chromium-doped GLS at 700 nm and 1020 nm have been observed. By comparisons of our spectroscopic data to that of transition metals doped into other hosts we determine the oxidation states of the transition metal ions and propose transitions for the observed spectroscopic peaks.

Hughes, Mark A.; Aronson, Jonathan E.; Brocklesby, William S.; Shepherd, David P.; Hewak, Daniel W.; Curry, Richard J.

2004-12-01

231

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

232

Spectral properties and shielding behavior of gamma irradiated MoO3-doped silicophosphate glasses  

NASA Astrophysics Data System (ADS)

Combined optical and infrared absorption spectra of prepared molybdenum ions in sodium silicophosphate host glasses were investigated before and after gamma irradiation with a dose of 8 Mrad (8×104 Gy). The undoped base sodium silicophosphate glass reveals strong charge transfer ultraviolet absorption but with no visible bands. This strong UV absorption is related to the presence of contaminated trace iron impurities (mainly Fe3+ ions) within the raw materials used for the preparation of this host glass. The MoO3 doped glasses exhibit extra characteristic absorption bands due to the presence of molybdenum ions in three possible valence states, the trivalent, pentavalent and hexavalent forms. Gamma irradiation of the base undoped glass increases the extension of optical absorption within the UV spectrum and produces an extra broad visible band centered at 520 nm. Such radiation-induced spectra are interpreted by assuming the formation of new induced color centers through the absorption of released electrons and formed positive holes during the irradiation process. Also, the possible formation of induced centers through photochemical transformation of some Fe2+ ions to Fe3+ ions by accepting positive holes. The presence of molybdenum ions is assumed to compete with the suggested irradiation reactions by capturing electrons and positive holes during the irradiation process. Infrared absorption spectra of the undoped and MoO3-doped glasses reveal broad IR vibrational bands which are attributed to the presence of combined characteristic vibrational IR modes due to main phosphate and partner silicate groups. The addition of MoO3 (0.5-1.5%) as dopant level causes no changes in the number and position of the main characteristic absorption bands. Gamma irradiation did not cause any marked changes in the IR spectra and the maintainance of the same main IR bands due to the stability of the network containing dual compact two glass-formers units and the presence of molybdenum ions as shielding component. The changes in intensities of some bands are correlated with changes in bond angles and/or bond lengths of some structural units as previously suggested by several authors. E.S.R. data of the MoO3-doped glasses reveal indication of several valence states of molybdenum ions as suggested by optical measurements. The irradiated samples show the change in resonance spectra of high MoO3-doped glasses which can be related to change of some Mo6+ to Mo5+ ions as deduced from optical spectra.

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

2013-11-01

233

Ultraviolet and white photon avalanche upconversion in Ho3+-doped nanophase glass ceramics  

NASA Astrophysics Data System (ADS)

Ho3+-doped fluoride nanophase glass ceramics have been synthesized from silica-based oxyfluoride glass. An intense white emission light is observed by the naked eye under near infrared excitation at 750nm. This visible upconversion is due to three strong emission bands in the primary color components, red, green, and blue. Besides, ultraviolet signals are also recorded upon the same excitation wavelength. The excitation mechanism of both the ultraviolet and the visible emissions is a photon avalanche process with a relatively low pump power threshold at about 20mW. The total upconverted emission intensity has been estimated to increase by about a factor of 20 in the glass ceramic compared to the precursor glass, in which an avalanche type mechanism is not generated.

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

2005-01-01

234

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

SciTech Connect

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

Lahoz, F.; Martin, I.R.; Calvilla-Quintero, J.M. [Departmento de Fisica Fundamental y Experimental, Electronica y Sistemas, University of La Laguna, 38206 La Laguna, Tenerife (Spain)

2005-01-31

235

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

NASA Astrophysics Data System (ADS)

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

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

1999-12-01

236

[Investigation on the fabrication and spectrum properties of Yb3+ -doped silicate laser glasses].  

PubMed

Two kinds of Yb3+ doped silicate laser glass with little difference were produced by high temperature of melting process. The absorption and emission spectra of the two glass samples were tested by the correlative spectrographs; the integral absorption cross section, stimulated emission cross section, fluorescence line-width, fluorescence lifetime, least particle count, saturation pump intensity and least pump intensity of the Yb3+ -doped laser glasses were calculated respectively, and by comparison it was found that the chart of the absorption cross section is similar to the stimulated emission cross section calculated by the reciprocity method, and is very different from the stimulated emission cross section calculated by the Fuchbauer-Ladenburger method. This result is precisely in line with the theoretical analysis. The line-types of the absorption spectra of the two glass samples are almost the same, and the first peak value of absorption is located at 975 nm while the second peak value is at 908 nm. As the two components of the samples are not very different, the accord of the line-types of the absorption spectra indicates that the makeup of the glass material is the primary factor influencing the line-type of the absorption spectra. The fluorescence spectra of the two glass samples are very different, and the first fluorescence peak value of sample one is located at 993 nm with the second peak value at 1029 nm, while the first fluorescence peak value of sample two is located at 1 035 nm with the second peak value at 994 nm. The cause of the major difference in the fluorescence spectra of two samples lies in the different doping density of Yb3+. By comparison we found that the laser performance of sample two is better than that of sample one. The test shows that both samples are suitable for drawing fiber. PMID:19950658

Dong, Shi-rui; Hou, Lan-tian; Jin, Tao-tao; Han, Ying; Xia, Chang-ming; Niu, Jing-xia; Zhou, Gui-yao; Liang, Dan-hua; Li, Rui

2009-09-01

237

[Optical and spectral parameters in Ce3+ -doped gadolinium gallium aluminum garnet glass-ceramics].  

PubMed

The crystalline phases of Ce3+ -doped gadolinium gallium aluminum garnet (GGAG) glass-ceramics were investigated by X-ray diffraction, and the fluorescence spectra were recorded under the pumping of blue light-emitting diode (LED) using an integrating sphere of 10-inch in diameter, which connected to a CCD detector. The spectral power distribution of the glass-ceramics was obtained from the measured spectra first, and then the quantum yield was derived based on the photon distribution. The quantum yield of Ce3+ emission in GGAG glass-ceramics is 29.2%, meanwhile, the color coordinates and the correlated color temperature (CCT) of combined white light were proved to be x = 0.319, y = 0.349 and 6086 K, respectively. Although the quantum yield is a little smaller than the value in Ce3+ -doped YAG glass-ceramics, the CCT of the combined white light is much smaller than that in the latter. The optical behavior of GGAG glass-ceramics provides new vision for developing comfortable LED lighting devices. PMID:20302098

Gong, Hua; Zhao, Xin; Yu, Xiao-bo; Setsuhisa, Tanabe; Lin, Hai

2010-01-01

238

Spectroscopic properties of transparent Er-doped oxyfluoride glass-ceramics with GdF?.  

PubMed

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

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

2015-01-01

239

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

PubMed

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

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

2010-10-11

240

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; published online 28 April 2008 A zero-phonon component of the 1.5 m emission band of Er3+ in the nano-glass-ceramics 32 SiO2 9 AlO1.5 31.5 CdF2 18.5 PbF2 5.5 ZnF2 :3.5 ErF3 mol %, shifts to higher energy and splits

Moshchalkov, Victor V.

241

Nanodiamond in tellurite glass Part I: origin of loss in nanodiamond-doped glass  

E-print Network

Tellurite glass fibers with embedded nanodiamond are attractive materials for quantum photonic applications. Reducing the loss of these fibers in the 600-800 nm wavelength range of nanodiamond fluorescence is essential to exploit the unique properties of nanodiamond in the new hybrid material. In the first part of this study, we report the effect of interaction of the tellurite glass melt with the embedded nanodiamond on the loss of the glasses. The glass fabrication conditions such as melting temperature and concentration of NDs added to the melt were found to have critical influence on the interaction. Based on this understanding, we identified promising fabrication conditions for decreasing the loss to levels required for practical applications.

Ebendorff-Heidepriem, Heike; Ji, Hong; Greentree, Andrew D; Gibson, Brant C; Monro, Tanya M

2014-01-01

242

Crystallization studies on rare-earth co-doped fluorozirconate-based glasses  

PubMed Central

This work focuses on the structural changes of barium chloride (BaCl2) nanoparticles in fluorochlorozirconate-based glass ceramics when doped with two different luminescent activators, in this case rare-earth (RE) ions, and thermally processed using a differential scanning calorimeter. In a first step, only europium in its divalent and trivalent oxidation states, Eu2+ and Eu3+, is investigated, which shows no significant influence on the crystallization of hexagonal phase BaCl2. However, higher amounts of Eu2+ increase the activation energy of the phase transition to an orthorhombic crystal structure. In a second step, nucleation and nanocrystal growth are influenced by changing the structural environment of the glasses by co-doping with Eu2+ and trivalent Gd3+, Nd3+, Yb3+, or Tb3+, due to the different atomic radii and electro-negativity of the co-dopants. PMID:23745010

Passlick, C.; Johnson, J.A.; Schweizer, S.

2013-01-01

243

Simulations of silver-doped germanium-selenide glasses and their response to radiation  

PubMed Central

Chalcogenide glasses doped with silver have many applications including their use as a novel radiation sensor. In this paper, we undertake the first atomistic simulation of radiation damage and healing in silver-doped Germanium-selenide glass. We jointly employ empirical potentials and ab initio methods to create and characterize new structural models and to show that they are in accord with many experimental observations. Next, we simulate a thermal spike and track the evolution of the radiation damage and its eventual healing by application of a simulated annealing process. The silver network is strongly affected by the rearrangements, and its connectivity (and thus contribution to the electrical conductivity) change rapidly in time. The electronic structure of the material after annealing is essentially identical to that of the initial structure.

2014-01-01

244

Preparation and optical properties of silica gel–glass doped with ZnSe nanoparticles  

Microsoft Academic Search

The silica gel–glasses doped with zinc selenide (ZnSe) nanoparticles were prepared by the sol–gel technique which was followed by a reductive thermal treatment. The samples were characterized by transmission electron microscopy (TEM), X-ray diffraction pattern (XRD), optical absorption and photoluminescence spectra. The blue shift of the absorption edge can be changed and used to evaluate the average size of the

Minqiang Wang; Yaohui Xue; Zhonghai Lin; Xiao Huo; Jianping Li; Xi Yao

2008-01-01

245

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

246

Electron transport studies in single transition metal ions doped borophosphate glasses  

Microsoft Academic Search

Three series of boro-phosphate glasses doped with single transition metal ions, Cuo, Fe2O3 and CoO have been prepared by melt quenching method and investigated for room temperature density and dc electrical conductivity in the temperature range from 325 to 600K. The density increased with increasing transition metal ions concentration in all the three series. The measured conductivities were in the

B. Vijaya kumar; T. Sankarappa; Santoshkumar; S. S. Veena

2009-01-01

247

PbS quantum-dot-doped glasses for ultrashort-pulse generation  

NASA Astrophysics Data System (ADS)

We investigate the use of PbS quantum-dot-doped glasses as saturable absorbers for ultrashort-pulse lasers by means of absorption bleaching experiments and numerical analysis of the pulse shaping process using the Haus' master equation. We explain the mode-locking mechanism and the limitations of these absorbers. The generation of transform-limited fs pulses is predicted by soliton mode locking initiated by the absorption saturation of higher excited states of the quantum-dot saturable absorber.

Wundke, K.; Pötting, S.; Auxier, J.; Schülzgen, A.; Peyghambarian, N.; Borrelli, N. F.

2000-01-01

248

Energy transfer upconversion on neodymium doped phosphate glasses investigated by Z-scan technique  

NASA Astrophysics Data System (ADS)

Time-resolved Z-scan measurements were employed to characterize energy transfer upconversion on the phosphate glass matrix, named PAN (P2O5-Al2O3-Na2CO3), doped with increasing Nd3+ concentrations. It was observed a linear dependence of the upconversion parameter with the dopant agent, which indicates the presence of a static and dynamic energy transfer processes. The critical inversion density was also evaluated for the same set of samples.

Lima, W. J.; Martins, V. M.; Monte, A. F. G.; Messias, D. N.; Dantas, N. O.; Bell, M. J. V.; Catunda, T.

2013-07-01

249

Influence of high magnetic field on the luminescence of Eu3+-doped glass ceramics  

NASA Astrophysics Data System (ADS)

Rare earth (RE) doped materials have been widely exploited as the intriguing electronic configuration of RE ions offers diverse functionalities from optics to magnetism. However, the coupling of magnetism with photoluminescence (PL) in such materials has been rarely reported in spite of its fundamental significance. In the present paper, the effect of high pulsed magnetic field on the photoluminescence intensity of Eu3+-doped nano-glass-ceramics has been investigated. In our experiment, Eu-doped oxyfluoride glass and glass ceramic were prepared by the conventional melt-quenching process and controlled heat treatment. The results demonstrate that the integrated PL intensity of Eu3+ decreases with the enhancement of magnetic field, which can be interpreted in terms of cooperation effect of Zeeman splitting and magnetic field induced change in site symmetry. Furthermore, as a result of Zeeman splitting, both blue and red shift in the emission peaks of Eu3+ can be observed, and this effect becomes more prominent with the increase of magnetic field. Possible mechanisms associated with the observed magneto-optical behaviors are suggested. The results of the present paper may open a new gate for modulation of luminescence by magnetic field and remote optical detection of magnetic field.

Jiang, Wei; Zhang, Junpei; Chen, Weibo; Chen, Ping; Han, Junbo; Xu, Beibei; Zheng, Shuhong; Guo, Qiangbing; Liu, Xiaofeng; Qiu, Jianrong

2014-09-01

250

Fabrication of Rare Earth-Doped Transparent Glass Ceramic Optical Fibers by Modified Chemical Vapor Deposition  

E-print Network

Rare earth (RE) doped silica-based optical fibers with transparent glass ceramic (TGC) core was fabricated through the well-known modified chemical vapor deposition (MCVD) process without going through the commonly used stage of post-ceramming. The main characteristics of the RE-doped oxyde nanoparticles namely, their density and mean diameter in the fibers are dictated by the concentration of alkaline earth element used as phase separating agent. Magnesium and erbium co-doped fibers were fabricated. Optical transmission in term of loss due to scattering as well as some spectroscopic characteristics of the erbium ions was studied. For low Mg content, nano-scale particles could be grown with and relatively low scattering losses were obtained, whereas large Mg-content causes the growth of larger particles resulting in much higher loss. However in the latter case, certain interesting alteration of the spectroscopic properties of the erbium ions were observed. These initial studies should be useful in incorporati...

Blanc, Wilfried; Nguyen, Luan; Bhaktha, S N B; Sebbah, Patrick; Pal, Bishnu P; Dussardier, Bernard

2011-01-01

251

Optical and luminescent properties of Sm3+ doped tellurite glasses  

NASA Astrophysics Data System (ADS)

Glasses with chemical composition of (62-x) TeO2 + 25 ZnO + 8 K2O + 5 CaO + x Sm2O3 (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 4G?6H, 4G?6H and 4G?6H transitions respectively. From the emission spectra and J-O intensity parameters, various radiative parameters were calculated from the excited 4G to the lower lying 6 state decrease with the increase of the Sm3+ ions concentration. The energy transfer mechanism that leads to the quenching of 4G 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 Sm3+ ions.

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

2013-03-01

252

Development and characterization of a new Er3+-doped phosphate glass for planar waveguide lasers and amplifiers  

NASA Astrophysics Data System (ADS)

A new Er3+ doped phosphate glass exhibiting an excellent durability in both boiling water and NaNO3 molten salt was developed. Ion-exchange process of this glass was investigated by treating glass samples in a variety of salt bathes with various exposure times. Planar waveguide with one mode at 1.54 micrometers and three modes at 632.8 nm was demonstrated. Spectral properties of Er3+ in this glass were characterized by measuring absorption and emission spectra, and fluorescence lifetimes. Emission cross section of Er3+ in this glass was calculated to be 0.76 X 10-20 cm2 using McCumber theory. Our preliminary experimental results indicate this new Er3+ doped glass is an excellent material for ion-exchanged waveguide lasers and amplifiers.

Jiang, Shibin; Honkanen, Seppo; Luo, Tao; Hwang, Bor-Chyuan; Nunzi Conti, Gualtiero; Myers, Michael J.; Rhonehouse, Daniel L.; Peyghambarian, Nasser

1998-04-01

253

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

254

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

255

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

256

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

257

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

258

Development and characterization of a new Er3+-doped phosphate glass for planar waveguide lasers and amplifiers  

Microsoft Academic Search

A new Er3+ doped phosphate glass exhibiting an excellent durability in both boiling water and NaNO3 molten salt was developed. Ion-exchange process of this glass was investigated by treating glass samples in a variety of salt bathes with various exposure times. Planar waveguide with one mode at 1.54 micrometers and three modes at 632.8 nm was demonstrated. Spectral properties of

Shibin Jiang; Seppo Honkanen; Tao Luo; Bor-Chyuan Hwang; Gualtiero Nunzi Conti; Michael J. Myers; Daniel L. Rhonehouse; Nasser Peyghambarian

1998-01-01

259

Appearance of fast ionic conduction in AgI-doped chalcogenide glass powders prepared by mechanical milling  

Microsoft Academic Search

(AgI)x(As2Se3)1?x glass powders were successfully obtained up to 70mol% AgI content by the mechanical milling method. Electrical conductivities, which show the exponential increase with addition of AgI, are comparable to the values of the corresponding melt-quenched glasses. The conductivity of 60mol% AgI-doped glass shows great increase at the early period of the milling. A DSC signal for the ?–? phases

Mai Sekine; Y. Suzuki; H. Ueno; Y. Onodera; T. Usuki; T. Nasu; S. Wei

2007-01-01

260

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

Microsoft Academic Search

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?2Scm?1 at 300°C.

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

2003-01-01

261

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

262

Glass fibres of pure and erbium- or neodymium-doped yttria-alumina compositions  

NASA Astrophysics Data System (ADS)

Optical fibres doped with lanthanide or transition-metal elements can serve as in-line lasers and amplifiers for fibre-optic telecommunications systems. In general, most such fibre lasers use conventional silica-glass fibres doped with erbium or neodymium. But silicon dioxide absorbs strongly in the infrared for wavelengths of greater than 4µm or so, limiting the infrared range over which such lasers can operate. Some other oxide materials do not absorb significantly until longer wavelengths-the absorption coefficient of crystalline silica at 4µm is equal to that of yttrium oxide at 7.1µm and of sapphire (a form of alumina) at 5.1µm, for example. Glass fibres made from these materials would therefore expand the range of fibre lasers into the mid-infrared. But molten oxides that do not contain silica typically have a viscosity too low to support fibre-pulling processes. Here we demonstrate that containerless processing, in which a molten sample is levitated by a flow of inert gas, permits sufficient undercooling of molten yttrium aluminium garnet (YAG:Y3Al5O12) to access a viscosity range conducive to fibre-pulling. The process is particularly effective if the molten material of stoichiometric YAG composition is doped with Nd2O3 in place of Y2O3, or with excess Al2O3; and it should also work with other dopants, because molten oxides are good solvents. Fibres could be drawn from a melt doped with Er2O3 in the presence of excess Al2O3. These fibres have the potential to extend the operating range of oxide glass-fibre lasers.

Weber, J. K. Richard; Felten, John J.; Cho, Benjamin; Nordine, Paul C.

1998-06-01

263

Chalcogenide glasses for infrared applications: New synthesis routes and rare earth doping  

NASA Astrophysics Data System (ADS)

Chalcogenide glasses and glass-ceramics present a high interest for the production of thermal imaging lenses transparent in the 3--5 microm and 8--12 microm windows. However, chalcogenide glasses are conventionally synthesized utilizing expensive and single use silica ampoules sealed under vacuum. The present work addresses the development of innovative synthesis methods for chalcogenide glasses that can present an alternative to the silica tube route. The first approach assessed by melting the raw starting elements in reusable silica containers appears inadequate for synthesis of glasses from the system Ge-Ga-Se. The second synthesis approach consists of the preparation of amorphous chalcogenide powders by ball milling of raw elements (mechanosynthesis) followed by consolidation of the as-prepared powders. Hot Uniaxial Pressing is suitable for sintering of powders with compositions stable against crystallization but uncontrolled crystallization occurs for the unstable compositions. In contrast, consolidation through Spark Plasma Sintering (SPS) allows production of bulk glasses with large dimensions in a short duration and at relatively low temperatures. Moreover, increased SPS treatment duration yields infrared transparent glass-ceramics with enhanced mechanical properties. This innovative synthesis method combining mechanosynthesis and SPS has been patented in the framework if this study. The controlled etching of 80GeSe2-20Ga2Se 3 glass-ceramics in acid solution yields nanoporous materials with enhanced surface area. The porous layer created on the surface of the glass-ceramic plays the role of anti-reflection coating and increases the optical transmission in the infrared range by 10%. These materials present potential for the production of sensors with increased sensitivity. The influence of indium and lead addition on the thermal and optical properties of the 80GeSe2-20Ga2Se3 glass is also assessed. Increased In or Pb contents tend to decrease the Tg and shift the optical band gap toward higher wavelengths. A systematic ceramization study emphasizes the difficulty of controlling the crystallization for glasses in the systems GeSe2-Ga2Se3-In2Se 3 and GeSe2-Ga2Se3-PbSe. No crystallization of the In2Se3 and PbSe crystalline phase was obtained. Finally, the possibility of producing rare-earth doped 80GeSe2 -20Ga2Se3 glass-ceramics transparent in the infrared region up to 16 microm is demonstrated. Enhanced photoluminescence intensity and reduced radiative lifetimes are observed with increased crystallinity in these materials.

Hubert, Mathieu

264

The chemical durability of glass and graphite-glass composite doped with cesium oxide  

NASA Astrophysics Data System (ADS)

The role of temperature in determining the chemical stability of a waste form, as well as its leach rate, is very complex. This is because the dissolution kinetics is dependent both on temperature and possibility of different rate-controlling mechanisms that appear at different temperature regions. The chemical durability of Alumina-Borosilicate Glass (ABG) and Glass-Graphite Composite (GGC), bearing Tristructural Isotropic (TRISO) fuel particles impregnated with cesium oxide, were compared using a static leach test. The purpose of this study is to examine the chemical durability of glass-graphite composite to encapsulate coated fuel particles, and as a possible alternative for recycling of irradiated graphite. The test was based on the ASTM C1220-98 methodology, where the leaching condition was set at a temperature varying from 298 K to 363 K for 28 days. The release of cesium from ABG was in the permissible limit and followed the Arrhenius's law of a surface controlled reaction; its activation energy (Ea) was 65.6 ± 0.5 kJ/mol. Similar values of Ea were obtained for Boron (64.3 ± 0.5) and Silicon (69.6 ± 0.5 kJ/mol) as the main glass network formers. In contrast, the dissolution mechanism of cesium from GGC was a rapid release, with increasing temperature, and the activation energy of Cs (91.0 ± 5 kJ/mol) did not follow any model related to carbon kinetic dissolution in water. Microstructure analysis confirmed the formation of Crystobalite SiO2 as a gel layer and Cs+1 valence state on the ABG surface.

Hamodi, Nasir H.; Abram, Timothy J.; Lowe, Tristan; Cernik, Robert J.; López-Honorato, Eddie

2013-01-01

265

NMR Studies of Magnetic and Fast Ionic Conducting Amorphous Borates  

Microsoft Academic Search

NMR studies were performed on lead borate glasses containing significant concentrations of Fe(,2)O(,3) and on lithium borate glasses containing lithium halides (LiCl or LiF). ('11)B and ('207)Pb NMR investigations of glasses in the system x Fe(,2)O(,3)(.)y PbO(.)z B(,2)O(,3) (0 (LESSTHEQ) x (LESSTHEQ) 15.3 Mol %, z\\/y (DOT=) 3) revealed that the NMR line broadening contains Gaussian field-independent and field-dependent components,

Frank Bucholtz

1982-01-01

266

Optical and magneto-optical properties in Fe-doped glasses irradiated with femtosecond laser  

NASA Astrophysics Data System (ADS)

Optical, magnetic, and magneto-optical properties have been investigated for the ?-Fe2O3-doped transparent glasses irradiated with an infrared fs laser and subsequently annealed. The values of the saturation magnetization at room temperature for the irradiated glasses were increased compared with the as-prepared samples, which is due to the precipitation of the ferrimagnetic ferrite nanoparticles (NPs). By adding further dopants as precursors of plasmonic metals, Au or Al NPs were space-selectively precipitated together with the ferrite NPs in a confined region after irradiation and thermal annealing. In the case of the glass codoped with Al, magneto-optical Faraday effect was plasmonically enhanced and exhibited a negative distinct peak ascribed to a coupling between the ferrimagnetism of ferrite NPs and the localized surface plasmon resonance of Al NPs, while the glass, in which ferrite and Au NPs were precipitated, showed a positive enhancement of Faraday effect due to a coupling of plasmon resonance with diamagnetism of glass matrix.

Nakashima, Seisuke; Sugioka, Koji; Tanaka, Katsuhisa; Midorikawa, Katsumi; Mukai, Kohki

2013-12-01

267

Spectroscopic and radiative properties study of Nd 3+ doped cadmium-phosphate glasses  

NASA Astrophysics Data System (ADS)

A spectroscopic investigation is performed on Nd 3+ doped cadmium-phosphate glasses. The Judd-Ofelt analysis is applied to the glass system in order to evaluate their potential as both glass laser and amplifier materials. The phenomenological Judd-Ofelt parameters ?(2), ?(4), and ?(6) are determined, their values are 4.80×10 -20, 6.18×10 -20, and 7.14×10 -20 cm -2, respectively. The quality factor for glass system is 0.86. Predicted radiative decay rates and branching ratios of transitions from Nd 3+4F 3/2 state to the 4I J manifolds are determined and analyzed. The calculated lifetime of the 4F 3/2 metastable state of Nd 3+ is 31 ?s. The results showed that 4F 3/2 to 4I 11/2 transition, with fluorescence at 1056 nm, has the most potential for laser application. Photoluminescence up-conversion under excitation at 488 nm laser light exhibits three emission bands of Nd 3+ ions at 541 (green), 601 (orange), and 677 nm (red). These emission bands are assigned to 4G 7/2? 4I 9/2, 4G 7/2? 4I 11/2, and 4G 7/2? 4I 13/2 transitions, respectively. Analysis of luminescence spectra enhances the use of glass system in optical displays, lasers, and optical memory devices.

Mahmoud, K. H.

2010-12-01

268

Influence of mixed alkalis on spectroscopic parameters of Sm 3+, Dy 3+ doped chloroborate glasses  

NASA Astrophysics Data System (ADS)

This article reports the effect of mixed alkalis on the optical absorption and emission spectra of Sm 3+ and Dy 3+ doped chloroborate glass matrices of the compositions 69.5B 2O 3xLiCl(30 - x)NaCl0.5R 2O 3 and 69.5B 2O 3xLiCl(30 - x)KCl0.5R 2O 3 (where R = Sm and Dy and x = 5, 10, 15, 20 and 25). Using Judd-Ofelt theory, the spectral intensities and Judd-Ofelt intensity parameters ( ?2,?4 and ?6) were obtained from the measured absorption bands of the spectra. Using these intensity parameters, total radiative transition probabilities ( AT), radiative lifetimes ( ?R), branching ratios ( ?) and peak emission cross-sections ( ?P) were obtained for the two rare earth ions in these two glass matrices. Variation of these parameters with x in the glass matrix has been discussed. It is found that for Sm 3+ ion, the transition, 4G 5/2 ? 6H 9/2 shows highest emission cross-section and is maximum at x = 10 mol% in lithium-sodium and at x = 20 mol% in lithium-potassium glass matrices. For Dy 3+ ion, the transition, 4F 9/2 ? 6H 13/2 shows highest emission cross-section and is maximum at x = 20 mol% in lithium-sodium and at x = 10 mol% in lithium-potassium glass matrix.

Venkateswarlu, C.; Seshadri, M.; Ratnakaram, Y. C.

2011-04-01

269

Spectroscopic studies of copper doped alkaline earth lead zinc phosphate glasses  

NASA Astrophysics Data System (ADS)

In this paper spectroscopic investigation of Cu2+ doped alkaline earth lead zinc phosphate glasses was done through the spectroscopic techniques like X-ray diffraction, Ultra Violet (UV) absorption Spectroscopy, Electron Paramagnetic Resonance (EPR - X band), Fourier Transform Infra Red (FTIR) and Raman Spectroscopy. Alkaline earth lead zinc phosphate glasses containing 0.1% copper oxide (CuO) were prepared by the melt quenching technique. Spectroscopic studies indicated that there is a greater possibility for the copper ions to exist in Cu2+ state in these glasses. The optical absorption spectra indicated that the absorption peak of Cu2+ is a function of composition. The maxima absorption peak was reported at 862 nm for strontium lead zinc phosphate glass. Bonding parameters were calculated for the optical and EPR data. All these spectral results indicated clearly that there are certain structural changes in the present glass system with different alkaline earth contents. The IR and Raman spectra noticed the breaking of the P-O-P bonds and creating more number of new P-O-Cu bonds.

Sastry, S. Sreehari; Rao, B. Rupa Venkateswara

2014-02-01

270

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

271

Luminescence properties of rare earth and transition metal ions doped potassium lead borophosphate glass  

NASA Astrophysics Data System (ADS)

A series of potassium lead borophosphate glass doped with rare earth and transition metal ions were fabricated using melt-quenching method without annealing process. With the composition of glass 0.15K2O-0.15PbO-0.35B2O3-0.5P2O5 as host doped with 0.01 mole % of neodymium oxide, iron oxide, yttrium oxide, and titanium oxide as activator and different composition were used to investigate the luminescence effect by using Photoluminescence Spectroscopy and UV-Vis (Ultraviolet-Visible) spectrophotometer. By exciting the samples at different wavelength (200-900 nm), the excitation and emission profile were obtained and analyzed to study the energy transfer process. By referring to the spectra obtained, selected samples were also codoped among each other to obtain desired luminescence properties. UV-Visible spectroscopy results revealed the absorption and transmission wavelength of samples for targeted application as a selected band filter. Physical properties such as chemical stability and color of the samples were also recorded to correlate with PL and UV-Vis result. Certain rare earth activated samples displayed slight coloring under the visible wavelength especially Nd2+ ions doped samples displayed slight purplish.

Leong, P. M.; Eeu, T. Y.; Leow, T. Q.; Hussin, R.; Ibrahim, Z.

2013-05-01

272

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

273

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

274

Optical properties and generation of white light in Dy3+-doped lead phosphate glasses  

NASA Astrophysics Data System (ADS)

Dy3+-doped lead phosphate (PbPKANDy: P2O5+K2O+Al2O3+PbO+Na2O+Dy2O3) glasses were prepared by melt quenching technique and their optical properties have been studied. Judd-Ofelt parameters have been evaluated for 1.0 mol% Dy2O3-doped lead phosphate glass and inturn derived radiative properties for excited luminescent levels of Dy3+ ions. The yellow-to-blue emission intensity ratios and CIE chromaticity coordinates were calculated which have been used to evaluate white light emission as a function of the activator (Dy3+) ion concentration. The observed non-exponential decay nature and quenching of lifetime for higher Dy3+ ion concentration (?1.0 mol%) have been attributed due to energy transfer of dipole-dipole type between excited and unexcited Dy3+ ions. The PbPKANDy glasses exhibit better luminescence properties which are suitable for generation of white light.

Linganna, K.; Rao, Ch. Srinivasa; Jayasankar, C. K.

2013-03-01

275

Fabrication and luminescence behavior of phosphate glass ceramics co-doped with Er3+ and Yb3+  

NASA Astrophysics Data System (ADS)

Transparent phosphate glass ceramics co-doped with Er3+ and Yb3+ in the system P2O5?Li2O?CaF2?TiO2 were successfully synthesized by melt-quenching and subsequent heating. Formation of the nanocrystals was confirmed by X-ray powder diffraction. Judd-Ofelt analyses of Er3+ ions in the precursor glasses and glass ceramics were performed to evaluate the intensity parameters ?2,4,6. Under 975 nm excitation, intense upconversion (UC) and infrared emission (1545 nm) were observed in the glass ceramics by efficient energy transfer from Yb3+ to Er3+. The luminescence processes were explained and the emission cross section was calculated by Fuchtbauer-Ladenburg (F-L) formula. The results confirm the potential applications of Er3+/Yb3+ co-doped glass ceramics as laser and fiber amplifier media.

Yu, Xiaochen; Duan, Li; Ni, Lei; Wang, Zhuo

2012-08-01

276

Beta barium borate (BBO)  

Microsoft Academic Search

The paper contains a review of crystallographic, optical and nonlinear optical properties of beta barium borate (ß-BaB2O4 or BBO) crystal and presents a description of its typical applications in nonlinear optics and quantum electronics.

D. N. Nikogosyan

1991-01-01

277

Evidence of a cluster glass-like behavior in Fe-doped ZnO nanoparticles  

NASA Astrophysics Data System (ADS)

We report on the study of the structural and magnetic properties of crystalline Fe-doped ZnO nanoparticles with Fe content up to 10% synthesized by a co-precipitation method. The Rietveld analysis indicates that the Fe-doped ZnO nanoparticles are formed in a single phase wurtzite structure. DC magnetization (M) vs. applied magnetic field (H) curves obtained at 5 K show the occurrence of a ferromagnetic behavior. The coercive field and saturation magnetization depend on the Fe content. At room temperature, M vs. H curves show features consistent with a superparamagnetic state of nanoscale system. The temperature dependence of the AC and DC magnetic susceptibilities show features related to the thermal relaxation of the nano-sized particles. From the AC data analysis, a magnetic transition from the superparamagnetic to cluster-glass state is determined.

Ramos, J. E.; Montero-Muñoz, M.; Coaquira, J. A. H.; Rodríguez-Páez, J. E.

2014-05-01

278

Comparative toxicology of borates  

Microsoft Academic Search

Inorganic borates, including boric acid, Na, ammonium, K, and Zn borates generally display low acute toxicity orally, dermally,\\u000a and by inhalation. They are either not irritant or mild skin and eye irritants. Exceptions owing to physiochemical properties\\u000a do occur.\\u000a \\u000a Longer-term toxicological studies have been reported mainly on boric acid or borax where the properties are generally similar\\u000a on an equivalent

Susan A. Hubbard

1998-01-01

279

Enhanced broadband excited upconversion luminescence in Ho-doped glasses by codoping with bismuth.  

PubMed

We report enhanced green and red upconversion (UC) luminescence in Ho3+-doped oxyfluoride germanate glass by introducing bismuth near-infrared active centers as sensitizers. The UC excitation bands at 750 and 970 nm show a full width at half-maximum of 20 and 45 nm, respectively. Energy transfer from sensitizers, the excited-state absorption, and phonon-coupled absorption of Ho3+ jointly contribute to the enhanced UC luminescence. Our approach provides an efficient methodology to broaden the excitation bandwidth of UC luminescent materials, which may have the potential for promising application in solar cells. PMID:24978263

Xu, Beibei; Bai, Gongxun; Wang, Juechen; Guo, Qiangbing; Tan, Dezhi; Chen, Weibo; Liu, Xiaofeng; Zhou, Shifeng; Hao, Jianhua; Qiu, Jianrong

2014-05-15

280

Second-harmonic generation of thermally poled silver doped sodo-borophosphate glasses  

Microsoft Academic Search

Sodium niobium borophosphate glass, with a composition of 0.58(0.95NaPO3+0.05Na2B4O7)+0.42Nb2O5, has been doped with monovalent silver ions. Second harmonic generation (SHG) has been obtained from the poling treatment of this sample. The second order nonlinearity from the anode side was estimated from an analysis of transmitted polarized Maker-fringe patterns. Thanks to the original Maker fringe simulations, a value of 3 pm\\/V

Evelyne Fargin; Jérémy Soulié; Thierry Cardinal; Michel Lahaye; Vincent Rodriguez; Michel Couzi; Fre´de´ric Adamietz

2009-01-01

281

EPR and photoluminescence studies on lithium-potassium borophosphate glasses doped with Mn 2+ ions  

Microsoft Academic Search

The mixed alkali borophosphate xLi2O–(30?x)K2O–35B2O3–34.5P2O5 (5?x?25) glasses doped with 0.5mol% of manganese ions have been studied using EPR and photoluminescence techniques. The EPR spectra of all the investigated samples exhibit resonance signals which are characteristic of Mn2+ ions. The resonance signal with effective g value at g=2.02 exhibits a six line hyperfine structure. The zero-field splitting parameter (D) at room

C. R. Kesavulu; R. S. Muralidhara; J. L. Rao; R. V. Anavekar; R. P. S. Chakradhar

2009-01-01

282

X-ray absorption fine structure of aged, Pu-doped glass and ceramic waste forms  

Microsoft Academic Search

X-ray absorption spectroscopic (XAS) studies were performed on three compositionally identical, Pu-doped, borosilicate glasses prepared 15 years ago at different ?-activities by varying the 239Pu\\/238Pu isotopic ratio. The resulting ?-activities ranged from 1.9×107 to 4.2×109 Bq\\/g and have current, accumulated doses between 8.8×1015 to 1.9×1018 ?-decays\\/g. Two ceramic, polycrystalline zircon (ZrSiO4) samples prepared 16 years ago with 10.0 wt% Pu

N. J. Hess; W. J. Weber; S. D. Conradson

1998-01-01

283

High-concentration erbium-doped glasses, fiber amplifiers and lasers  

Microsoft Academic Search

Upconversion coefficients in a new high-concentration erbium-doped tellurite glass were obtained a schematic study of experiments and modeling. The upconversion coefficient for 4I13\\/2 + 4I13\\/2 --> 4I9\\/2 + 4I15\\/2 is found to be 2.74 × 10-18 cm3\\/s and for 4I11\\/2 + 4I 11\\/2 --> 4I15\\/2 + 2F 7\\/2 is 1.09 × 10-18 cm3\\/s. The performance of high concentration Er3+-Yb3+ -codoped

Yongdan Hu

2001-01-01

284

Saturation of absorption in noble metal doped nanocomposite glass film excited by evanescent light field  

NASA Astrophysics Data System (ADS)

A leaky-waveguide configuration is proposed for saturable absorbers. Evanescent field interaction between the leaky-mode and the absorber layer reduces material degradation at high power levels while providing control over the interaction length and thus the modulation strength and nonsaturable losses simply by tuning the coupling angle around the resonance of the leaky-mode. This concept was applied to a sol-gel silicon-dioxide glass film doped with gold nanoparticles. Saturation of the surface plasmon resonance absorption was demonstrated with modulation depths of up to 34% achieved.

Corbari, Costantino; Beresna, Martynas; Kazansky, Peter G.

2010-12-01

285

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

286

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

287

Fabrication of photonic crystals in rare-earth doped chalcogenide glass films for enhanced upconversion  

NASA Astrophysics Data System (ADS)

Gallium lanthanum oxysulfide (GLSO) is a promising host material for observing strong upconversion emission from trivalent rare-earth ions such as erbium (Er3+). Its attractive properties include high rare-earth solubility due to the lanthanum content of the glass former, a high refractive index (n = 2.2 at 550nm) for high radiative efficiency, and a low maximum phonon energy of approximately 425cm -1. Photonic crystals meanwhile can provide controlled light extraction, and may be capable of suppressing unwanted IR emission from lower lying metastable states. Here, we describe the fabrication of photonic crystals in annealed films of Er3+-doped GLSO deposited by RF sputtering. The most intense visible upconversion emission is observed in films annealed at 550°C, close to the bulk glass transition temperature. Hexagonal lattice photonic crystals are subsequently milled into the films using a focused ion beam (FIB). The milling parameters are optimized to produce the most vertical sidewall profile.

Pollard, M. E.; Knight, K. J.; Parker, G. J.; Hewak, D. W.; Charlton, M. D. B.

2012-02-01

288

Plasmonic enhanced luminescence in Er3+:Ag co-doped tellurite glass  

NASA Astrophysics Data System (ADS)

A series of erbium doped zinc tellurite glass samples with and without nanoparticles are prepared by the conventional melt-quenching method and their structural and spectroscopic characterizations are measured. Effect of silver nanoparticles on optical properties of samples is studied by annealing them for different time intervals. Efficient enhancement of upconversion emissions in the entire visible region is observed after 2 h annealing and assigned to strong localized electric field in vicinity of nanoparticles under excitation at 786 nm. The quench of green emissions (4S3/2 ? 4I15/2) by longer annealing time interval is described by energy transfer from silver nanoparticles to erbium ions. Improvements of radiative emissions show that the proposed glass and technique are promising to develop solid state lasers, color displays and nanophotonics devices.

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

2013-02-01

289

Effect of AgCl on spectroscopic properties of erbium doped zinc tellurite glass  

NASA Astrophysics Data System (ADS)

The Er3+ doped zinc tellurite glass containing Ag nanoparticles (NPs) were synthesized from high purity raw materials by melt quenching method and the influence of Ag NPs on the spectroscopic properties were investigated. The glasses are characterized using DTA, EDX, TEM, FTIR, UV-Vis-NIR and photoluminescence (PL) techniques. The DTA data reveal that the addition of silver chloride increased the thermal stability from 0.52 to 0.67 for samples without and with 2 mol% AgCl respectively. The sharp peaks in EDX spectra show the presence of Ag nanocrystallites. The TEM micrograph shows the distribution of NPs is Gaussian and the average size is estimated ˜10 nm. Seven absorption bands of erbium were evidenced in the UV-Vis-NIR measurements. Optical band gap and density were found to decrease with addition of AgCl concentration, while molar volume increased. The PL spectra exhibit four peaks corresponding to 2H11/2 ? 4I15/2, 4S3/2 ? 4I15/2, 4F9/2 ? 4I15/2 and 4S3/2 ? 4I13/2 transitions. An enhancement in the order of six times for 2 mol% of dopant and a subsequent quench in luminescence spectra of co-doped zinc tellurite glasses were observed. Such enhancements were attributed to silver nanoparticles with average size of 10 nm and absorption band centered at 552 nm. The studied glasses provide enormous scope to achieve the materials suitable for nanophotonics, solid state lasers and color displays.

Reza Dousti, M.; Sahar, M. R.; Ghoshal, S. K.; Amjad, Raja J.; Samavati, A. R.

2013-03-01

290

CsH5(PO4)2 doped glass membranes for intermediate temperature fuel cells  

NASA Astrophysics Data System (ADS)

This study reports the preparation of glass membranes doped with CsH5(PO4)2 by an optimized sol-gel method using phosphoric acid as a catalyst for tetraethylorthosilicate (TEOS) hydrolysis and the application of these membranes in intermediate temperature fuel cells (ITFCs). Infrared spectroscopy shows the formation of Si-O-P bonds and scanning electron microscopy shows that the glass membranes have smooth cross-sectional structures. Domains of CsH5(PO4)2 with sizes of 5-12 nm are uniformly distributed over the membrane cross section. The melting point of CsH5(PO4)2 in the glass membrane is lower by 20-40 °C than that for pure CsH5(PO4)2. For a glass membrane with a molar ratio of SiO2:CsH5(PO4)2:H3PO4 = 4:1:0.36, 62% of the pore volume is filled with CsH5(PO4)2 and shows the best electrochemical performance. The glass membrane shows high conductivity of 22 mS cm-1 at 219 °C. The membrane is novel because the silica support forms an interconnected matrix that provides stability, as shown by continuous operation at 210 °C for at least 50 h. A fuel cell assembled with the glass membrane exhibits an open circuit voltage of 0.94 V and a peak power density of 85 mW cm-2. The fuel cell produces a stable output voltage of 0.53 V for at least 50 h under a current density of 100 mA cm-2.

Qing, Geletu; Kikuchi, Ryuji; Takagaki, Atsushi; Sugawara, Takashi; Oyama, Shigeo Ted

2014-12-01

291

Broad-spectrum bactericidal activity of Ag(2)O-doped bioactive glass.  

PubMed

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 Ag(2)O. The bacteriostatic and bactericidal properties of this new material and of two other bioactive glass compositions, 45S5 Bioglass and BG, have been studied by using Escherichia coli, Pseudomonas aeruginosa, and Staphylococcus aureus as test microorganisms. Concentrations of AgBG in the range of 0.05 to 0.20 mg of AgBG per ml of culture medium were found to inhibit the growth of these bacteria. Not only was AgBG bacteriostatic, but it also elicited a rapid bactericidal action. A complete bactericidal effect was elicited within the first hours of incubation at AgBG concentrations of 10 mg ml(-1). 45S5 Bioglass and BG had no effect on bacterial growth or viability. The antibacterial action of AgBG is attributed exclusively to the leaching of Ag(+) ions from the glass matrix. Analytical measurements rule out any contribution to AgBG-mediated bacterial killing by changes in pH or ionic strength or the dissolution of other ionic species from the biomaterials. Our observations of the dissolution profiles of Ag(+) from AgBG in the presence and absence of bacteria are consistent with silver accumulation by the bacteria. PMID:12019112

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

2002-06-01

292

Ag nanoparticles enhanced near-IR emission from Er3+ ions doped glasses  

NASA Astrophysics Data System (ADS)

Vitreous materials containing rare-earth (RE) ions and metallic nanoparticles (NPs) attract considerable interest because the presence of the NPs may lead to an intensification of luminescence. In this work, the characteristics of 1.54 ?m luminescence for the Er3+ ions doped bismuthate glasses containing Ag NPs were studied under 980 nm excitation. The surface plasmon resonance (SPR) band of Ag NPs appears from 500 to 1500 nm. Transmission electron microscopic (TEM) image reveals that the Ag NPs are dispersed homogeneously with the size from 2 to 7 nm. The strength parameters ?t(t = 2, 4, 6), spontaneous emission probability (A), radiative lifetime (?) and stimulated emission section (?em) of Er3+ ions were calculated by the Judd-Ofelt theory. When the glass contains 0.2 wt% AgCl, the 1.54 ?m fluorescence intensity of Er3+ reaches a maximum value, which is 7.2 times higher than that of glass without Ag NPs. The Ag NPs embedded glasses show significantly fluorescence enhancement of Er3+ ions by local field enhancement from SPR.

Qi, Jiani; Xu, Tiefeng; Wu, Yi; Shen, Xiang; Dai, Shixun; Xu, Yinsheng

2013-10-01

293

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

294

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

295

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

296

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

297

Synthesis and Use of Borates of Polyatomic Alcohols for the Preparation of Liquid High-Level Wastes for Inclusion into Borophosphate Glass  

Microsoft Academic Search

Boro-organic reagents suitable for fluxing a solution of liquid high-level wastes in order to immobilize them in borophosphate\\u000a glass are synthesized by dissolving boric acid and sodium tetraborate in ethylene glycol and glycerin. The properties of the\\u000a reagents obtained are investigated, borophosphate glasses are synthesized, and it is shown that the vitrification process\\u000a using them presents no danger of an

M. B. Remizov; A. F. Bogdanov; I. I. Vdovkina; M. A. Biryukova

2005-01-01

298

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

299

Antibacterial activity of silver-doped silica glass microspheres prepared by a sol-gel method.  

PubMed

Various kinds of inorganic substances doped with silver ions have been developed as antibacterial materials, and some have already been commercialized. Previously, we successfully prepared colorless silica glass microspheres doped with silver ions in combination with aluminum ions by a sol-gel method. However, the antibacterial activity of the microspheres was not maintained for long periods in an aqueous environment, since the silver ions were located only in a thin layer near the surface of the microspheres. In this study, silica glass microspheres in which silver ions are uniformly distributed were attempted to be prepared. A tetraethoxysilane ethanol solution was mixed with aqueous silver nitrate and aluminum nitrate solutions to be subjected to almost simultaneous hydrolysis and polycondensation. An ammonia solution was then added, to form microspheres. Monodispersed microspheres about 0.1 microm in diameter were obtained, which did not show coloring even after heat treatment at 600-1000 degrees C, indicating that the silver in the microspheres took the form of Ag(+) ions and not colloid, even after the heat treatments. Microspheres heat-treated at temperatures ranging from 700 to 800 degrees C showed much higher antibacterial activity than commercial antibacterial zeolites and maintained their high antibacterial activities for long periods in an aqueous environment. Polypropylene plates and films mixed with the microspheres heat-treated at 800 degrees C showed excellent antibacterial properties. PMID:17285611

Masuda, Noriaki; Kawashita, Masakazu; Kokubo, Tadashi

2007-10-01

300

Research on mid-frequency errors in Nd-doped glass continuous polishing  

NASA Astrophysics Data System (ADS)

In the inertial confinement fusion (ICF) system, the mid-frequency errors of optical components will cause high-frequency modulation and nonlinear gain of laser beams. In this paper, theoretical simulations and experiments have been designed and operated, aiming at studying the effects of slotting methods on mid-frequency errors in Nd-doped glass continuous polishing. Based on Preston formula, theoretical simulations focus on the effects of slotting methods on the mid-frequency errors. The simulation results show that different slotting methods will cause different mid-frequency errors, and square and logarithmic shape grooves are easier to obtain smaller mid-frequency errors. On the basis of simulation results, two groups of experiments are carried out to do the Nd-doped glass continuous polishing. The results show that the mid-frequency error gradually decreases with the decrease of the spacing between grooves. The results also show that square shape groove is easier to get a smaller mid-frequency error than circular shape groove, which verifies the theoretical simulation results.

Cao, Jun; Dun, Aihuan; Wei, Chaoyang; Gu, Jianxun; Shao, Jianda

2014-08-01

301

Investigation on preparation and spectroscopic properties of Yb2+-doped silica-based glass prepared by the oxyhydrogen flame fusing process  

NASA Astrophysics Data System (ADS)

In this paper, we report the preparation and spectroscopic properties of Yb2+-doped silica-based glass prepared by the solid state reaction using the oxyhydrogen flame fusing process. The glass exhibits broadband emission in the visible region due to a 5d-4f transition of the rare earth ions. The emission peak wavelength and bandwidth are especially 505 nm and 147 nm for Yb2+-doped silica-based glass at the room temperature. The color coordinate calculation shows that the Yb2+-doped silica-based glass has a better color coordinate (0.28, 0.37) in the white light region.

Xia, Changming; Zhou, Guiyao; Han, Ying; Zhao, Xingtao; Wang, Chao; Hou, Lantian

2013-10-01

302

Near-IR emission from holmium–ytterbium co-doped alkali bismuth gallate and fluorophosphate fiber glass preforms  

Microsoft Academic Search

Spectroscopic characterization of fiber preforms fabricated with alkali bismuth gallate (KBG) and fluorophosphate glasses (FP) doped with Ho3+ and Yb3+ are reported. Luminescent properties of the preforms are studied in the near-IR spectral range using 2W, 975nm diode laser pumping. Results indicate that both glasses are potentially promising for lasing in the 1.2?m and in the 2.2–2.5?m spectral range.

M. Alejandrina Martínez Gámez; A. V. Kir’yanov; C. Wiechers; G. A. Kumar

2009-01-01

303

Investigations on spectroscopic properties of Pr3+ and Nd3+ doped zinc-alumino-sodium-phosphate (ZANP) glasses  

NASA Astrophysics Data System (ADS)

Zinc-alumino-sodium-phosphate (ZANP) glasses doped with rare earth metal ions (Nd3+ and Pr3+) with different concentrations (0.5, 1.0, 1.5, 2.0 and 2.5 mol%) were prepared by melt quenching technique. X-ray diffraction, SEM with EDS, Raman spectra, FTIR-spectra, DTA, absorption and luminescence spectra were recorded at room temperature for all the glass matrices and analyzed. X-ray diffraction profiles and SEM images confirmed the amorphous nature of the glass samples. The EDS spectrum of doped and undoped glasses reveals the chemical composition present in them. Structural information of these glass matrices was provided by FTIR and Raman spectra. From DTA analysis, the glass transition temperature (Tg) and crystallization temperature (Tc) were determined. From the absorption spectra, the Judd-Ofelt (J-O) parameters, ?? (? = 2, 4 and 6) and other radiative properties like transition probabilities (AR), radiative lifetimes (?R) and branching ratios (?R) were evaluated. Branching ratios and stimulated emission cross-sections show that 4F3/2 ? 4I11/2 transition of Nd3+ ion and 3P0 ? 3H4 transition of Pr3+ ion of the glasses under investigation have strong emission at 1060 and 490 nm respectively. The results obtained were compared with reports on similar glasses.

Brahmachary, K.; Rajesh, D.; Babu, S.; Ratnakaram, Y. C.

2014-05-01

304

Mineral oil soluble borate compositions  

SciTech Connect

Alkali metal borates are reacted with fatty acids or oils in the presence of a low hlb value surfactant to give a stable mineral oil-soluble product. Mineral oil containing the borate can be used as a cutting fluid.

Dulat, J.

1981-09-15

305

On the structure of biomedical silver-doped phosphate-based glasses from molecular dynamics simulations.  

PubMed

First-principles and classical molecular dynamics simulations of undoped and silver-doped phosphate-based glasses with 50 mol% P2O5, 0-20 mol% Ag2O, and varying amounts of Na2O and CaO have been carried out. Ag occupies a distorted local coordination with a mean Ag-O bond length of 2.5 Å and an ill-defined first coordination shell. This environment is shown to be distorted octahedral/trigonal bipyramidal. Ag-O coordination numbers of 5.42 and 5.54-5.71 are calculated for first-principles and classical methodologies respectively. A disproportionation in the medium-range phosphorus Q(n) distribution is explicitly displayed upon silver-doping via CaO substitution, approximating 2Q(2)?Q(1) + Q(3), but not on silver-doping via Na2O substitution. An accompanying increase in FWHM of the phosphorus to bridging oxygen partial pair-correlation function is strong evidence for a bulk structural mechanism associated with decreased dissolution rates with increased silver content. Experimentally, Ag2O ? Na2O substitution is known to decrease dissolution and we show this to be a result of Ag's local bonding. PMID:25069608

Ainsworth, Richard I; Christie, Jamieson K; de Leeuw, Nora H

2014-10-21

306

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

307

Spectral investigations of Sm3+ doped lead bismuth magnesium borophosphate glasses  

NASA Astrophysics Data System (ADS)

The multicomponent lead bismuth magnesium borophosphate glass systems (LBMBPS) doped with Samarium ions with the molar compositions of (50-x)PbO?xBi2O3?25MgHPO4?24B2O3?1Sm2O3 (where x=10, 20, 30, and 40) were fabricated using conventional melt quenching technique. The amorphous nature of these glass samples was confirmed with XRD studies. The spectral data from the optical absorption studies were employed to compute various spectroscopic parameters such as Judd-Ofelt intensity parameters. The Judd-Ofelt parameterization employed reflects the covalency and vibration frequencies of the ligands with Samarium ions. The radiative parameters such as radiative transition probabilities (A), the total radiative transitional probabilities (AT), radiative life times (?R), branching ratios (?) and absorption cross sections (?) were computed for certain lasing levels. The glass systems thus developed indicate their potential lasing candidature. The emission cross sections (?E) for the significant lasing transitions 4G5/2?6H5/2, 4G5/2?6H7/2, and 4G5/2?6H9/2 evaluated from the photoluminescence spectra were reported. The radiative properties obtained in our investigations suggest their lasing candidature.

Ravi Babu, Y. N. Ch.; Sree Ram Naik, P.; Vijaya Kumar, K.; Rajesh Kumar, N.; Suresh Kumar, A.

2012-09-01

308

Dielectric properties and conductivity in CuO and MoO 3 doped borophosphate glasses  

NASA Astrophysics Data System (ADS)

A novel set of glasses of the type (B 2O 3) 0.10-(P 2O 5) 0.40-(CuO) 0.50-x-(MoO 3) x, 0.05? x?0.50, have been investigated for dielectric properties in the frequency range 100 Hz-100 kHz and temperature range 300-575 K. From the total conductivity derived from the dielectric spectrum the frequency exponent, s, and dc and ac components of the conductivity were determined. The temperature dependence of dc and ac conductivities at different frequencies was analyzed using Mott's small polaron hopping model, and the high temperature activation energies have been estimated and discussed. The observed initial decrease in conductivity (ac and dc) and increase in activation energy with the addition of MoO 3 have been understood to be due to the hindrance offered by the Mo + ions to the electronic motions. The observed peak-like behavior in conductivity (dip-like behavior in activation energy) in the composition range 0.20-0.50 mol fractions of MoO 3 may be due to mixed transition effect occurring in the present glasses. The temperature dependence of frequency exponent, s, has been analyzed using different theoretical models. It is for the first time that the mixed transition metal ion (TMI) doped borophosphate glasses have been investigated for dielectric properties and conductivity over wide temperature and frequency ranges and the data have been subjected to a thorough analysis.

Vijaya Kumar, B.; Sankarappa, T.; Kumar, Santosh; Prashant Kumar, M.; Sadashivaiah, P. J.; Ramakrishna Reddy, R.

2009-11-01

309

Direct measurements of the terminal laser level lifetime in neodymium-doped crystals and glasses  

NASA Astrophysics Data System (ADS)

We have measured the terminal level lifetime ( tau 11/2) for the 1- mu m neodymium transition in several laser media, using a novel pump (2.41- mu m) and probe (1.06- mu m) technique. This method allows us to populate the 4I13/2 level directly and subsequently to monitor the terminal level 4 I11/2 population as a function of time by observing the change in integrated fluoresence of the 0.88- mu m emission for each time delay between the pump and the probe pulses. We developed a computer model to analyze the data and determined the upper and lower limits for the tau 11/2 lifetime. The results for some of the materials investigated are 115-225 ps for Nd:Y3Al5O12, 250-450 ps for Nd:LG-750 (phosphate glass), 535-740 ps for Nd:LG-660 (silicate glass), 896-1900 ps for Nd:YAlO3, and 10.5-20 ns for Nd:YLiF4. In addition, we found the lifetimes to be independent of the neodymium doping concentration for the phosphate and silicate glass samples investigated. Copyright (c) 1995 Optical Society of America

Bibeau, Camille; Payne, Stephen A.; Powell, Howard T.

1995-10-01

310

Effect of crystallization heat treatment on the microstructure of niobium-doped fluorapatite glass-ceramics  

PubMed Central

Our goal was to study the effect of heat treatment temperature and heating rate on the microstructure and crystalline phases and assess the domain of existence of sub-micrometer fluorapatite crystals in niobium-doped fluorapatite glass-ceramics for biomedical applications. Glass-ceramic specimens were prepared by casting and heat treatment between 700 and 1200°C using a fast or a slow heating rate. The microstructure was characterized by atomic force microscopy and scanning electron microscopy. Crystalline phases were analyzed by x-ray diffraction. AFM of the as-cast glass revealed that amorphous phase separation occurred in this system. XRD confirmed the presence of fluorapatite in all specimens, together with forsterite and enstatite at higher temperatures. Both heating rate and heat treatment temperature strongly influenced microstructure and crystallinity. A dual microstructure with sub-micrometer fluorapatite crystals and polygonal forsterite crystals was obtained when slow heating rates and crystallization temperatures between 950 and 1100°C were used. Needle-shaped fluorapatite crystals appeared after heat treatment above 1100°C. Fast heating rates led to an increase in crystal size. Heat treatment temperatures should remain below 1100°C, together with slow heating rates, to prevent crystal dissolution, and preserve a dual microstructure of finely dispersed sub-micrometer crystals without growth of needle-shaped crystals. PMID:22454333

Denry, I.; Holloway, J.A.; Gupta, P.K.

2012-01-01

311

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

312

Engineering rare-earth-doped heavy metal oxide glasses for 2-5 ?m lasers  

NASA Astrophysics Data System (ADS)

The electronic states in trivalent rare-earth ions offer an excellent opportunity for designing efficient fibre and bulk lasers for atmospheric remote sensing and LIDAR technology. The first part of this review article focuses on engineering passive fibres for 2-5 ?m transmission. The fabrication of single-mode tungsten tellurite optical fibres from high purity bulk glass rods is described. Fibres with a numerical aperture of 0.1 and core diameter of 10+/-2 ?m have been drawn using suction and rod-in-tube techniques of fibre preform fabrication. Losses of 2.3 dBm-1 at 974 nm have been measured. These fibres are of interest for use as passive transmission fibre or active fibres for lasing in the 2-5 ?m spectral region. The use of heavy metal oxides in the fabrication of glass leads to extended infrared transmission. In the 2nd part of the review we compare the slope efficiencies of Tm3+ and Tm3+/Ho3+ doped glasses and fibres for 1950-2080 nm lasers using a range of pumping schemes in tellurite and germanium oxide hosts. We also explain the importance of choosing 1950-2080 nm tunable lasers as a pump source for stimulated emission at longer wavelengths.

Richards, Billy D. O.; Jha, Animesh; Dorofeev, Vitaly; Manzur, Tariq

2010-04-01

313

Structural, thermal, and optical properties of Er3+/Yb3+ co-doped oxyhalide tellurite glasses, glass-ceramics and ceramics  

NASA Astrophysics Data System (ADS)

Glass-ceramics and ceramics containing nano-crystals of different phases doped with Er3+/Yb3+ ions have been successfully prepared by heat treatment of the precursor oxyhalide glasses synthesized by the melt-quench method. X-ray diffraction patterns and transmission electron microscopy (TEM) images verify the precipitation of nano-crystals. Emission of Er3+ enhances several times when Yb3+ ion is added with the matrix. The Stark splitting and the intensity of different emission bands increase to a great extent when we approach to ceramics from glasses via glass-ceramics. The intensity of the blue and green emission bands increases much faster than the red and NIR emission bands. Intense upconversion emission observed by the naked eye has been quantified in terms of standard chromaticity diagram (CIE). Power dependence study shows that the upconversion of NIR radiation to visible radiation takes place mainly via photon avalanche (PA) process.

Joshi, C.; Rai, R. N.; Rai, S. B.

2012-04-01

314

Broadband near infrared emission in antimony-germanate glass co-doped with erbium and thulium ions  

NASA Astrophysics Data System (ADS)

Antimony-germanate glasses co-doped with Er/Tm ions as a material for active waveguides application have been investigated. In result of optimizations of rare earths, concentration wide (??FWHM=420 nm) luminescence emission in the range of 1.4 to 1.9 ?m was obtained for molar composition of 1%Er2O3: 0.25%TmO. The influence of the molar ratio of active ions on the luminescence spectra has been investigated. Luminescent properties of fabricated glass indicate that elaborated glass is promising material for broad tunable integrated laser sources and broadband optical amplifiers.

Dorosz, Dominik; Zmojda, Jacek; Kochanowicz, Marcin

2014-07-01

315

Stable glass-ceramic sealants for solid oxide fuel cells: Influence of Bi 2O 3 doping  

Microsoft Academic Search

Diopside (CaMgSi2O6) based glass-ceramics in the system SrO–CaO–MgO–Al2O3–B2O3–La2O3–Bi2O3–SiO2 have been synthesized for sealing applications in solid oxide fuel cells (SOFC). The parent glass composition in the primary crystallization field of diopside has been doped with different amounts of Bi2O3 (1, 3, 5 wt.%). The sintering behavior by hot-stage microscopy (HSM) reveals that all the investigated glass compositions exhibit a two-stage shrinkage

Ashutosh Goel; Maria J. Pascual; José M. F. Ferreira

2010-01-01

316

Characterization of radiative properties of Nd2O3 doped phosphate and silicate glasses for solid state laser  

NASA Astrophysics Data System (ADS)

Nd2O3 doped calcium aluminium phosphate and calcium aluminium silicate glasses prepared to compare their absorption and emission properties. Radiative lifetime of the excited state 4F3/2 derived by Judd-Ofelt theory applied to the absorption spectra. Using the photoluminescence spectrometer the steady state emission and relaxation time from excited energy level recorded under green light excitation. Phosphate glass has higher emission cross-section, higher radiative lifetime but less quantum efficiency due to non-radiative quenching through hydroxyl ions compared to silicate glass for Nd3+:4F3/2?4I9/2 emission.

Nandi, P.; Shukla, R.; Goswami, M.; Sudarsan, V.

2014-04-01

317

Photoluminescence and excitation spectroscopy of Er-doped As2S3 glass: Novel broad band excitation mechanism  

NASA Astrophysics Data System (ADS)

Photoluminescence (PL) and photoluminescence excitation (PLE) spectroscopy carried out on bulk samples of Er:As2S3 glasses demonstrate that Er3+ is incorporated in optically active sites in the glass and gives rise to a broad ˜1500-1600 nm, 4I13/2?4I15/2 emission spectrum similar to those observed in Er-doped oxide glasses. In addition to the expected 980 nm (4I15/2?4I11/2) Er3+ PLE band, the 1500-1600 nm Er3+ PL band in the glass exhibits a remarkably broad PLE spectrum which extends from the As2S3 Urbach absorption edge at ˜550 nm to beyond 1000 nm. This broad PLE band corresponds closely to an exponential PLE band observed in the ``band tail'' spectral range for Er-doped Ge33As12Se55 glasses. These unusual PLE spectra indicate that in Er-doped chalcogenide glasses there is an additional broad-band, below gap, extrinsic absorption mechanism which efficiently excites the characteristic 1550 nm, 4I13/2?4I15/2 Er3+ emission band. It is not possible to determine at present whether the Er dopants themselves are responsible for the broad band absorption which excites the Er3+ PL bands, or if photoexcited carriers attributable to absorption by other impurities transfer their energy to the excited states of the Er3+ 4f shells. Microscopic characterization techniques reveal that the Er2S3-doped glasses also contain residual Er2S3 crystallites which give rise to sharp, narrow line 1550, 980, and 810 nm Er3+ optical spectra characteristic of polycrystalline Er2S3. The temperature dependence of the Er2S3 PL and PLE spectra enables the energy levels of the 4I13/2 excited state and 4I15/2 ground state manifolds to be determined.

Gu, S. Q.; Ramachandran, S.; Reuter, E. E.; Turnbull, D. A.; Verdeyen, J. T.; Bishop, S. G.

1995-04-01

318

Low-temperature specific heat of rare-earth-doped silicate glasses D. A. van de Straat, J. Baak, and H. B. Brom  

E-print Network

Low-temperature specific heat of rare-earth-doped silicate glasses D. A. van de Straat, J. Baak-order terms. The existence of a quasilinear contribution to the low- temperature specific heat of glasses1 work we show that the low- temperature specific heat depends on the composition of the silicate glass

Schmidt, Thomas

319

Magnetic-field effect on the phonon echoes in a rare-earth-doped glass F. Lerbet and G. Bellessa  

E-print Network

1251 Magnetic-field effect on the phonon echoes in a rare-earth-doped glass F. Lerbet and G the TLS and the rare-earth ions are perturbed by the magnetic field, whereas the photon echoes arises from frequency range 450-800 MHz. The echo amplitude increases by a factor 3 as the magnetic field increases from

Boyer, Edmond

320

Effect of Ce 3+ codoping on Er 3+-doped bismuth-germanate glass and fiber under 980 nm excitation  

NASA Astrophysics Data System (ADS)

Er 3+/Ce 3+ codoped bismuth-germanate glasses with the composition of Bi 2O 3-GeO 2-Ga 2O 3-Na 2O were prepared by the conventional melt-quenching method. The absorption spectra, fluorescence spectra, upconversion emission and lifetimes of Er 3+ ions were measured, and the effects of Ce 3+-doping on the spectroscopic properties of 1.53 ?m band fluorescence of Er 3+ ion were investigated based on the analysis of energy transfer between Er 3+ and Ce 3+ ions. The results indicate that the 1.53 ?m band fluorescence intensity can be improved evidently with the Ce 3+-doped concentration under the excitation of 980 nm. Meanwhile, the theoretical simulation based on the population rate equation and light power propagation equation indicates that the C + L band signal gain can also be improved dramatically by introducing Ce 3+ ions into the Er 3+-doped bismuth-germanate glass fiber. Therefore, it is necessary to introduce Ce 3+ ions when Er 3+-doped bismuth-germanate glass with low phonon energy is applied to the 1.53 ?m band broad Er 3+-doped fiber amplifier (EDFA).

Zhou, Yaxun; Wang, Sen; Lin, Jianhui; Ye, Miaoqun; Yang, Gaobo

2011-05-01

321

Enhanced light emission near 2.7 ?m from Er-Nd co-doped germanate glass  

NASA Astrophysics Data System (ADS)

Laser glass gain medium that can convert low cost 808 nm diode laser into 2.7 ?m has attracted considerable interest due to its potential application for medical surgery fiber laser system. In this study, enhanced 2.7 ?m emission has been achieved in Er3+:germanate glass by co-doping with Nd3+ ions under the excitation of an 808 nm diode laser. In the co-doped sample, the experimental results show that the harmful visible emissions via up-conversion were effectively restricted. The reduction of 1.5 ?m emission was also detected in the co-doped sample, which indicates significant de-excitation of 4I13/2 Er3+ ion through energy transfer and non-radiative decay in Nd3+ ions. In conclusion, the 2.7 ?m emission enhancement achieved was due to the increased optical absorption of 808 nm, efficient energy transfer (ET) with efficiency of 81.73% between Er3+ and Nd3+ ions, and shortening the lifetime of the lower lasing level 4I13/2 Er3+ in the co-doped sample. Therefore, Er3+/Nd3+ co-doped germanate glass could be used to fabricate fiber optical gain media for 2.7 ?m laser generation.

Bai, Gongxun; Tao, Lili; Li, Kefeng; Hu, Lili; Tsang, Yuen Hong

2013-04-01

322

Rate equation analysis of nanocrystal-enhanced upconversion in neodymium-doped glass ceramics  

NASA Astrophysics Data System (ADS)

Rare-earth ions embedded in glassy matrices are promising materials for photon upconversion processes, e.g. to convert near infrared light to frequencies above the band gap of a solar cell to make it available for electrical power generation. One strategy to optimize the efficiency of such upconversion processes is to embed the active ions in a host matrix with minimal losses to non-radiative relaxation. For the model system of trivalent neodymium in fluorochlorozirconate (FCZ) glass it has been shown recently that a uniform growth of BaCl2 nanocrystals inside such glasses can decrease the probability of multi-phonon relaxation (MPR) drastically, leading to a huge increase in upconversion intensity for monochromatic illumination. To identify the key processes which may enhance or diminish the total upconversion efficiency, a comprehensive description for the optical dynamics of neodymium in FCZ glass ceramics has been developed on the basis of a rate equation system, including ion-photon, ion-phonon, and ion-ion interactions. An effective medium approach is utilized to account for the neodymium located in BaCl2 nanocrystals or the FCZ glass bulk, respectively. The numerous parameters required to enable for a reliable numerical simulation of the processes are obtained from theoretical approaches like Judd-Ofelt theory, as well as from experimental studies of luminescence decay after femtosecond excitation at various wavelengths and luminescence spectra under cw illumination at 800 nm wavelength. This rate equation model enables for a convenient, self-consistent description of all time-resolved and cw experiments on samples with different neodymium concentration. On this basis, the power dependence of upconversion spectra can be simulated in good agreement with the experimental result for 800 nm cw illumination. The model therefore forms an excellent tool for optimizing the upconversion efficiency of rare-earth doped luminescent material also under realistic (broadband illumination) conditions.

Skrzypczak, U.; Pfau, Charlotte; Seifert, G.; Schweizer, Stefan

2014-05-01

323

Spectroscopic and laser properties of Sm³? ions doped lithium fluoroborate glasses for efficient visible lasers.  

PubMed

The Sm(3+)-doped lead barium zinc lithium fluoroborate (LBZLFB) glasses of composition 20PbO + 5BaO + 5ZnO + 10LiF + (60-x) B(2)O(3) + xSm(2)O(3), (where x=0.1, 0.5, 1.0, 1.5 and 2.0 mol%) have been prepared by conventional melt quenching technique and their structural and spectroscopic behavior were studied and reported. The amorphous nature of these glass samples was confirmed with XRD studies. The FT-IR and FT-Raman spectra reveal that, the glasses contain BO(3), BO(4), non-bridging oxygen and strong OH bonds. The bonding parameters and the oscillator strengths were determined from the absorption spectra. These parameters have been used to obtain the Judd-Ofelt intensity parameters. Using these intensity parameters various radiative and laser properties were predicted. The values of J-O intensity parameters suggested an increase in the degree of symmetry of the local ligand field at Sm(3+) sites. The decay rates for the (4)G(5/2) level of Sm(3+) ions have been measured and are found to be single exponential at lower concentrations (<1.0 mol%) and turn into non-exponential at higher concentrations (?1.0 mol%), due to energy transfer through cross-relaxation. From the emission characteristic parameters of (4)G(5/2) level, it is concluded that the LBZLFB glasses could be useful for photonic devices like visible lasers, fluorescent display devices and optical amplifiers, operated in the visible region. PMID:23261619

Zulfiqar Ali Ahamed, Sd; Madhukar Reddy, C; Deva Prasad Raju, B

2013-02-15

324

Spectroscopic and radiative properties of Sm3+-doped K-Mg-Al phosphate glasses  

NASA Astrophysics Data System (ADS)

Sm3+-doped K-Mg-Al phosphate glasses were prepared and characterized through various spectroscopic techniques such as optical absorption, excitation, photoluminescence spectra and decay rate analysis at room temperature to derive spectroscopic and radiative properties of Sm3+ ions in these glasses. Energy parameters for the 4f5 electronic configuration of Sm3+ ion in K-Mg-Al phosphate glass have been determined using free-ion Hamiltonian model. Judd-Ofelt (JO) analysis has been applied to evaluate the JO intensity parameters, ?? (?=2, 4 and 6), and in turn radiative properties such as radiative transition probability, branching ratio, radiative lifetime and peak stimulated emission cross-section for the fluorescent 4G5/2 level of Sm3+ ion have been determined. The fluorescence decay rates exhibit single exponential at lower concentrations (?0.1 mol%) and turn into non-exponential at higher concentrations (?0.5 mol%). The experimental lifetime for the 4G5/2 level as a function of Sm3+ ions concentration decreases from 2.77 to 0.74 ms when the concentration is increased from 0.05 to 2.0 mol% of Sm2O3 due to energy transfer process. The non-exponential decay rates are well-fitted to Inokuti-Hirayama model for S=6 indicating that the nature of the energy transfer process is of dipole-dipole type. The systematic analysis on decay rates indicates that the energy transfer mechanism depends on Sm3+ ion concentration as well as glass composition.

Srinivasa Rao, Ch.; Jayasankar, C. K.

2013-01-01

325

Synthesis and evaluation of rare-earth doped glasses and crystals for optical refrigeration  

NASA Astrophysics Data System (ADS)

This research focused on developing and characterizing rare-earth doped, solid-state materials for laser cooling. In particular, the work targeted the optimization of the lasercooling efficiency in Yb3+ and Tm3+ doped fluorides. The first instance of laser-induced cooling in a Tm3+-doped crystal, BaY2F8 was reported. Cooling by 3 degrees Kelvin below ambient temperature was obtained in a single-pass pump geometry at lambda = 1855 nm. Protocols were developed for materials synthesis and purification which can be applied to each component of ZBLANI:Yb 3+/Tm3+ (ZrF4 -- BaF2 -- LaF3 -- AlF3 -- NaF -- InF3: YbF3/TmF3) glass to enable a material with significantly reduced transition-metal impurities. A method for OH- impurity removal and ultra-drying of the metal fluorides was also improved upon. Several characterization tools were used to quantitatively and qualitatively verify purity, including inductively-coupled plasma mass spectrometry (ICP-MS). Here we found a more than 600-fold reduction in transition-metal impurities in a ZrCl2O solution. A non-contact spectroscopic technique for the measurement of laser-induced temperature changes in solids was developed. Two-band differential luminescence thermometry (TBDLT) achieved a sensitivity of ˜7 mK and enabled precise measurement of the zero-crossing temperature and net quantum efficiency. Several Yb3+-doped ZBLANI glasses fabricated from precursors of varying purity and by different processes were analyzed in detail by TBDLT. Laser-induced cooling was observed at room temperature for several of the materials. A net quantum efficiency of 97.39+/-0.01% at 238 K was found for the best ZBLANI:1%Yb 3+ laser-cooling sample produced from purified metal-fluoride precursors, and proved competitive with the best commercially procured material. The TBDLT technique enabled rapid and sensitive benchmarking of laser-cooling materials and provided critical feedback to the development and optimization of high-performance optical cryocooler materials. Also presented is an efficient and numerically stable method to calculate time-dependent, laser-induced temperature distributions in solids, including a detailed description of the computational procedure and its implementation. The model accurately predicted the zero-crossing temperature, the net quantum efficiency, and the functional shape of the transients, based on input parameters such as luminescence spectra, dopant concentration, pump properties, and several well-characterized material properties.

Patterson, Wendy

326

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

327

Magnetic properties and homogeneous distribution of Gd{sup 3+} ions in gadolinium molybdenum borate glass with high Gd{sub 2}O{sub 3} content  

SciTech Connect

Highlights: ? The magnetic susceptibility of Gd{sub 2}O{sub 3}–MoO{sub 3}–B{sub 2}O{sub 3} glass was examined in T = 1.8–300 K. ? The effective magnetic moment was ?{sub eff} = 7.87 ?{sub B}. ? The Weiss constant was ? = ?0.7 K. ? Gd{sup 3+} ions are distributed homogeneously as paramagnetic ions down to T = 1.8 K. -- Abstract: The magnetic susceptibility and specific heat of 21.25Gd{sub 2}O{sub 3}–63.75MoO{sub 3}–15B{sub 2}O{sub 3} (mol%) glass showing the crystallization of ferroelastic ??-Gd{sub 2}(MoO{sub 4}){sub 3} crystals are examined in the temperature range of T = 1.8–300 K to clarify magnetic and distribution states of Gd{sup 3+} ions. The magnetic susceptibility obeys the Curie–Weiss law, giving the effective magnetic moment of ?{sub eff} = 7.87 ?{sub B} and the Weiss constant of ? = ?0.7 K. Any peak such as ?-type anomaly is not observed in the temperature dependence of specific heat in T = 1.8–5 K. It is suggested that Gd{sup 3+} ions in the glass with a high Gd{sub 2}O{sub 3} content of 21.25 mol% are distributed homogeneously and randomly as paramagnetic ions down to T = 1.8 K without inducing any strong magnetic interaction. The present study suggests that glasses based on the MoO{sub 3}–B{sub 2}O{sub 3} system are good hosts for the homogeneous solubility of a large amount of rare-earth oxides.

Suzuki, F.; Honma, T. [Department of Materials Science and Technology, Nagaoka University of Technology, 1603-1 Kamitomioka-cho, Nagaoka 940-2188 (Japan)] [Department of Materials Science and Technology, Nagaoka University of Technology, 1603-1 Kamitomioka-cho, Nagaoka 940-2188 (Japan); Doi, Y.; Hinatsu, Y. [Division of Chemistry, Graduate School of Science, Hokkaido University, Sapporo 060-0810 (Japan)] [Division of Chemistry, Graduate School of Science, Hokkaido University, Sapporo 060-0810 (Japan); Komatsu, T., E-mail: komatsu@mst.nagaokaut.ac.jp [Department of Materials Science and Technology, Nagaoka University of Technology, 1603-1 Kamitomioka-cho, Nagaoka 940-2188 (Japan)

2012-11-15

328

Eu3+ doped 1La2O3:2WO3:1B2O3 glass and glass-ceramic  

NASA Astrophysics Data System (ADS)

In WO3-La2O3-B2O3 system, glasses were obtained in the region between 20 and 30 mol% La2O3. A liquid-phase separation region was observed near the WO3-B2O3 side. A glass with nominal composition 50WO3:25L2O3:25B2O3 doped with Eu2O3 was synthesized by melt quenching method. The obtained glass was characterized by X-ray diffraction (XRD), differential thermal analysis (DTA), UV-vis, infrared spectroscopy (IR) and photoluminescence spectroscopy (PL). According to the DTA data, Eu3+ ions decrease the glass transition temperature from 621 °C to 574 °C and crystallization temperature from 690 °C to 677 °C. Structural model for the glass network was suggested on the base of IR and UV-vis spectral investigations. It was established that WO4 and WO6 structural units (620-960 cm-1) and BO3 and BO4 polyhedra (1050-1380 cm-1) build up the glass network. During vitrification partial transformation of WO4 to WO6 and BO3 to BO4 was proved. The quenched glass is transparent in the visible region and exhibits typical absorption bands of Eu3+ ions due to the 4f transitions 5D0 ? 7Fj (j = 0-4). A glass-ceramic consisting of LaBWO6:Eu3+ nanocrystals with enhanced photoluminescence emissions is synthesized. The intensity of emission increases drastically in the glass-crystalline sample compared with the glass and polycrystalline sample.

Aleksandrov, L.; Iordanova, R.; Dimitriev, Y.; Georgiev, N.; Komatsu, T.

2014-06-01

329

Structure and vibrational modes of AgI-doped AsSe glasses: Raman scattering and ab initio calculations  

SciTech Connect

We report an investigation of the structure and vibrational modes of (AgI){sub x} (AsSe){sub 100-x}, bulk glasses using Raman spectroscopy and first principles calculations. The short- and medium-range structural order of the glasses was elucidated by analyzing the reduced Raman spectra, recorded at off-resonance conditions. Three distinct local environments were revealed for the AsSe glass including stoichiometric-like and As-rich network sub-structures, and cage-like molecules (As{sub 4}Se{sub n}, n=3, 4) decoupled from the network. To facilitate the interpretation of the Raman spectra ab initio calculations are employed to study the geometric and vibrational properties of As{sub 4}Se{sub n} molecular units that are parts of the glass structure. The incorporation of AgI causes appreciable structural changes into the glass structure. AgI is responsible for the population reduction of molecular units and for the degradation of the As-rich network-like sub-structure via the introduction of As-I terminal bonds. Ab initio calculations of mixed chalcohalide pyramids AsSe{sub m}I{sub 3-m} provided useful information augmenting the interpretation of the Raman spectra. -- Graphical abstract: Raman scattering and ab initio calculations are employed to study the structure of AgI-AsSe superionic glasses. The role of mixed chalcohalide pyramidal units as illustrated in the figure is elucidated. Display Omitted Research highlights: {yields} Doping binary As-Se glasses with AgI cause dramatic changes in glass structure. {yields} Raman scattering and ab initio calculations determine changes in short- and medium-range order. {yields} Three local environments exist in AsSe glass including a network sub-structure and cage-like molecules. {yields} Mixed chalcohalide pyramids AsSe{sub m}I{sub 3-m} dominate the AgI-doped glass structure.

Kostadinova, O. [Foundation for Research and Technology Hellas, Institute of Chemical Engineering and High Temperature Chemical Processes, P.O. Box 1414, Patras GR-26504 (Greece); Chrissanthopoulos, A. [Foundation for Research and Technology Hellas, Institute of Chemical Engineering and High Temperature Chemical Processes, P.O. Box 1414, Patras GR-26504 (Greece); Department of Chemistry, University of Patras, Patras GR-26504 (Greece); Petkova, T. [Institute of Electrochemistry and Energy Systems (IEES), Bulgarian Academy of Sciences, Sofia (Bulgaria); Petkov, P. [Laboratory of Thin Film Technology, Department of Physics, University of Chemical Technology and Metallurgy, Sofia (Bulgaria); Yannopoulos, S.N., E-mail: sny@iceht.forth.g [Foundation for Research and Technology Hellas, Institute of Chemical Engineering and High Temperature Chemical Processes, P.O. Box 1414, Patras GR-26504 (Greece)

2011-02-15

330

Corrosion of soda lime silicate glasses co-doped with Gd2O3 and Y2O3  

NASA Astrophysics Data System (ADS)

Corrosion behaviors of Gd2O3 and Y2O3 co-doped silicate glasses have been carried out at low reaction progress. The better enhance effect of co-doping with Gd2O3 and Y2O3 on the silicate glass resistance against attacking of neutral and acid media is observed, while the alkaline resistance is Y2O3 > Gd2O3 + Y2O3 > Gd2O3. Moreover, extreme value is also observed in variation of released ions concentration, pH value and mass loss of glass when substituting Y2O3 for Gd2O3.

Wang, Mitang; Li, Mei; Cheng, Jinshu; He, Feng; Liu, Zhaogang; Hu, Yanhong

2014-01-01

331

Spectroscopic study and white-light simulation using praseodymium-doped fluorogermanate glass as single phosphor for white LEDs  

NASA Astrophysics Data System (ADS)

Praseodymium-doped fluorogermanate 60PbGeO3-20PbF2-20CdF2 nano-structured phosphors were synthesized by thermal treatment of precursor glasses. Luminescence features of praseodymium ions incorporated into low-phonon-energy PbF2 nanocrystals dispersed in the fluorogermanate glass matrix was evaluated. The luminescence spectra exhibited visible emission signals peaked at 490, 525, 613, and 643 nm. White-light emission was observed in praeodymium single-doped phosphor excited using a LED at 460 nm. The dependence of the luminescence emission intensity upon annealing temperature, and rare-earth concentration was also evaluated. The results indicated the existence of optimum annealing temperature and activator ion concentration to obtain intense emission light with CIE 1931 chromaticity coordinates within the white-light boundary region. Results suggest that the novel nanocomposite glass material herein reported is a promising phosphor for white-light LED applications.

Gouveia-Neto, Artur S.; Rios, Nathalia P. S. M.; Bueno, Luciano A.

2012-12-01

332

Optical and spectroscopic properties of soda lime alumino-silicate glasses doped with erbium and silver  

NASA Astrophysics Data System (ADS)

Spectroscopic properties of Ag/Er co-doped soda lime silicate glasses have been studied with the aim of assessing the effective role of silver as a sensitizer for erbium. Changes in spectroscopic properties of Er 3+ as a function of silver addition to the base composition have been measured. Transmission electron microscopy (TEM), absorption as well as photoluminescence measurements in the visible and infrared spectral region, particularly 4I 13/2 ? 4I 15/2 transition of the Er 3+ ion were performed; excitation wavelengths in the range from 325 to 808 nm were used. Enhancement of the Er 3+ luminescence at 1.54 ?m was observed when Ag was added.

Carmo, A. P.; Bell, M. J. V.; Da Costa, Z. M.; Anjos, V.; Barbosa, L. C.; Chillcce, E. F.; Giehl, J. M.; Pontuschka, W. M.

2011-10-01

333

Optical limiting and excited-state absorption in fullerene solutions and doped glasses  

SciTech Connect

We report the ground state and excited state optical absorption spectra in the visible and near infrared for several substituted fullerenes and higher fullerenes in toluene solutions. Based on these measurements, broadband predictions of the optical limiting performance of these molecules can be deduced. These predictions are then tested at 532 to 700 nm in intensity-dependent transmission measurements. We observe optical limiting in all fullerenes measured; higher fullerenes show the greatest potential for limiting in the near infrared (650-1000 nm), while substituted C{sub 60} shows optimal limiting in the visible (450-700 nm). We observe dramatically reduced limiting for solid forms of C{sub 60} (thin films and C{sub 60}-doped porous glasses), indicating that efficient optical limiting in fullerenes requires true molecular solutions.

McBranch, D.; Smilowitz, L.; Klimov, V. [and others

1995-09-01

334

Quantum cutting mechanism in Tb3+-Yb3+ co-doped oxyfluoride glass  

NASA Astrophysics Data System (ADS)

Rate equations were created to describe cooperative quantum cutting phenomena, which incorporated the interactions between donor Tb3+ and acceptor Yb3+ ions. Two judgment criteria were developed for the excitation power dependence and time-resolved luminescence spectra of donor and acceptor ions, which can be used to verify the proposed mechanism. Under the excitation of a 473 nm continuous wave laser, the emission intensities of Tb3+ and Yb3+ increased linearly with the excitation power. The decay curve of Yb3+ indicated two distinct contributions: the fast decay time of its own lifetime, and the slow decay time representing the lifetime of the 5D4 energy level of Tb3+. The experimental results meet the two judgment criteria, which confirmed the proposed cooperative quantum cutting mechanism in Tb3+-Yb3+ co-doped oxyfluoride glass.

Duan, Qianqian; Qin, Feng; Wang, Dan; Xu, Wei; Cheng, Jianmin; Zhang, Zhiguo; Cao, Wenwu

2011-12-01

335

Formaldehyde degradation by photocatalytic Ag-doped TiO2 film of glass fiber roving.  

PubMed

The photocatalytic Ag doped TiO2 porous films were prepared by sol-gel method and dip coated on glass fiber roving. The sol composed of titanium (IV) isopropoxide, triethanolamine, ethanol and nitric acid followed by calcination of the film at 500 degrees C for 1 hour with a heating rate of 3 degrees C/min. The surface morphology and properties of synthesized TiO2 films were characterized by X-ray diffraction, atomic forced microscope and scanning electron microscope. A laboratory photocatalytic reactor was set up to carry out photoactivity of the prepared catalysts. The results show that TiO2-Ag and TiO2-Ag-TEA porous films give highest rate of formaldehyde gas degradation. It can be noted that triethanolamine exhibits two effects on TiO2 composite films; one is its effect on porous film structure and second is a reverse effect of hindrance of anatase growth. PMID:21137974

Ubolchonlakate, Kornkanok; Sikong, Lek; Tontai, Tienchai

2010-11-01

336

High repetition rate femtosecond laser irradiation-induced elements redistribution in Ag-doped glass  

NASA Astrophysics Data System (ADS)

A 250 kHz femtosecond laser was used to induce a one-step precipitation of Ag nanoparticles and the simultaneous element redistribution in Ag ion doped glass. After femtosecond laser exposure, a ring-shape region was formed. Besides, as a result of an optical spherical aberration effect, a nonuniform laser intensity distribution along the incident direction caused most of the formed Ag nanoparticles to precipitate in the lower part of cross section of this structure. By an EPMA analysis, the relative concentration of the Ag element was both high in the center and in the boundary of the ring-shape region. These Ag nanoparticles could potentially increase the refractive index in their precipitation regions. We proposed that the induced ion redistribution and the precipitation of Ag nanoparticles should be due to the heat accumulation effect by the high repetition rate femtosecond laser irradiation.

Dai, Y.; Yu, G.; He, M.; Ma, H.; Yan, X.; Ma, G.

2011-06-01

337

Thermal lens measurements of fluorescence quantum efficiency in Nd 3+-doped fluoride glasses  

Microsoft Academic Search

In this work we used a thermal lens (TL) method in the dual beam mod-mismatched configuration, to determine the fluorescence quantum efficiency, ?. Three kinds of Nd3+-doped fluoride glasses were studied: fluorozirconate 53ZrF4–29BaF2–4.5LaF3–3.5AlF3–10NaF–XNdF3 (ZBLAN); fluoroaluminate 20YF3–40AlF3–20BaF2–20CaF2–XNdF3 (YABC) and fluoroindate 30PbF2–20GaF3–15InF3–15ZnF2–20CaF2–XNdF3 (PGIZCa); with X=1 or 2 mol%. For all these samples we obtained the quantum efficiency, ?, between 0.80–0.94 and 0.67–0.76

A. A. Andrade; T. Catunda; R. Lebullenger; A. C. Hernandes; M. L. Baesso

2001-01-01

338

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

339

Bulk Nd3+-doped tellurite glass laser at 1.37 ?m  

NASA Astrophysics Data System (ADS)

We have demonstrated, for the first time to our knowledge, lasing at 1.37 ?m in a tellurite-based glass host doped with 0.5 mol.% neodymium: Nd3+:(0.8)TeO2-(0.2)WO3. The gain-switched laser could be operated with 59 ?J threshold pulse energy as well as 5.5% slope efficiency. As high as 6 ?J-pulses with a duration of 1.74 ?s were obtained. The pulse repetition rate was 1 kHz. The emission cross section from the threshold analysis turned out to be 1.57×10-20 cm2 at 1370 nm by taking into account excited-state absorption from 4F3/2 to 4G7/2 energy level. Furthermore, the ratio of excited-state absorption to the emission cross section was found out to be 0.78 by using the slope efficiency value.

Cankaya, H.; Sennaroglu, A.

2010-04-01

340

The Importance of Using Some Glass Systems as Standard in Transmission Spectrophotometry in the Visible and Ultraviolet Regions  

Microsoft Academic Search

This study deals with the possibility of using a system of glass borates as a former, Na2O and pbO as modifiers doped with Cu++ 0.1 wt.% , 3 wt.% Er2O3 , 3 wt.% H2O3 and 0.2 wt.% H2O3 chromophors in the system, as a standard filter in the visible, Uv and IR regions. In an instrument as complex as a

El-Sayed Mostafa; Moenis Azooz

2006-01-01

341

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

342

Third-order optical nonlinearity at 800 and 1300 nm in bismuthate glasses doped with silver nanoparticles.  

PubMed

Large and ultrafast third-order optical nonlinearities in Ag-doped bismuthate glasses which are prepared by incorporating Ag ions into bismuthate glasses to form Ag nanoparticles through a consecutive melting-quenching-annealing technique are reported. Due to the high refractive index of bismuthate glass, surface plasmon resonance (SPR) of Ag nanoparticles is extendable to 1400 nm, resulting in a higher nonlinear refractive index than bismuthate glass. Femtosecond Z-scans show that the nonlinear refractive index, as high as 9.4 × 10(-17) and 5.6 × 10(-18) m(2) W(-1) at 800 and 1300 nm, respectively, can be achieved by selecting an optimized concentration of Ag nano-sized particles. And two-photon absorption at 800 nm is suppressed due to a blue shift in the band-gap of Ag-doped bismuthate glasses, as compared to pristine bismuthate glasses. Optical Kerr shutter technique reveals that these nonlinearities have a relaxation time of < 1 ps. PMID:24921537

Chen, Feifei; Cheng, Junwen; Dai, Shixun; Xu, Zhe; Ji, Wei; Tan, Ruiqin; Zhang, Qinyuan

2014-06-01

343

Blue-white tunable luminescence for white light-emitting diodes and wideband near-infrared luminescence from Sm3+-doped borophosphate glass  

NASA Astrophysics Data System (ADS)

Highly transparent samarium (Sm3+) doped borophosphate glasses were prepared using the melt-quenching technique. The tunable light emission and wideband near-infrared luminescence properties of Sm3+-doped glasses were investigated systemically. Tuning the Sm3+ concentration and excitation wavelength can generate hues that vary from blue to white. Two wide luminescence bands in the 850 nm to 1070 nm range and in the 1100 nm to 1250 nm range, respectively, were also achieved. The results suggest that Sm3+-doped borophosphate glasses can be used as conversion materials for blue light-emitting diode chips to generate white light-emitting diodes and for optical amplification.

Sheng, Qiuchun; Shen, Yinglong; Liu, Shuang; Li, Wentao; Chen, Danping

2012-08-01

344

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

345

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

346

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

347

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?cm(2) 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

348

Spectral studies on Cr 3+ ions doped in sodium-lead borophosphate glasses  

NASA Astrophysics Data System (ADS)

Electron paramagnetic resonance (EPR), optical absorption and emission spectra of Cr 3+ ions doped in (30- x) (NaPO 3) 6+30PbO+40B 2O 3+ xCr 2O 3 ( x=0.5, 2.0, 3.0, 4.0 and 5.0 mol%) glasses have been studied. The EPR spectra exhibit resonance signals with effective g values at g?4.55 and g?1.97. The EPR spectra of x=3.0 mol% of Cr 2O 3 in sodium-lead borophosphate glass sample were studied at various temperatures (295-123 K). The intensity of the resonance signals increases with decrease in temperature. The optical absorption spectrum exhibits four bands characteristic of Cr 3+ ions in octahedral symmetry. From the analysis of the bands, the crystal-field parameter Dq and the Racah interelectronic repulsion parameters B and C have been evaluated. The emission spectrum exhibit one broad band characteristic of Cr 3+ ions in octahedral symmetry. This band has been assigned to the transition 4T 2g (F)? 4A 2g (F). Correlating EPR and optical data, the molecular bonding coefficient ( ?) has been evaluated.

Kiran, N.; Kesavulu, C. R.; Suresh Kumar, A.; Rao, J. L.

2011-05-01

349

Spectral studies on Mn 2+ ions doped in sodium-lead borophosphate glasses  

NASA Astrophysics Data System (ADS)

Electron paramagnetic resonance (EPR), optical absorption, and luminescence spectral studies of Mn 2+ ions doped in (30- x) (NaPO 3) 6+30PbO+40B 2O 3+ xMnO 2 ( x=1.0, 2.0, 3.0, 4.0, and 5.0 mol%) glasses have been studied. The EPR spectra exhibit resonance signals with effective g value at geff?2.02 with six line hyperfine structure. A weak resonance signal with effective g value at geff?4.3 is also observed for higher concentrations of Mn 2+ ions. The EPR spectra of x =3.0 mol% of Mn 2+ in sodium-lead borophosphate glass sample have been studied at various temperatures. It is observed that the resonance signal intensity decreases with increase in temperature. The optical absorption spectrum exhibits bands characteristic of Mn 2+ ions in octahedral symmetry. From the analysis of the bands, the crystal-field parameter Dq and the Racah interelectronic repulsion parameters B and C have been evaluated. The emission spectrum exhibits single broad band in the green region.

Kiran, N.; Kesavulu, C. R.; Suresh Kumar, A.; Rao, J. L.

2011-10-01

350

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

351

Formation of sub-surface silver nanoparticles in silver-doped sodium-lead-germanate glass  

NASA Astrophysics Data System (ADS)

The formation of silver nanoparticles in 60GeO2-20PbO-20Na2O bulk glass doped with 0.15 wt% of Ag has been studied by optical methods in the near ultraviolet-to-near infrared and mid-infrared ranges. A clear optical absorption band, which grows when increasing the annealing temperature, is observed around 460 nm, as a consequence of the surface plasmon resonance in the Ag nanoparticles. From the simultaneous analysis of optical transmittance and spectroscopic ellipsometry spectra in the near ultraviolet-to-near infrared range, it is demonstrated that the nanoparticles are surprisingly formed only in a thin layer (some tens of nm thick) underneath the sample surfaces. The potential of such a simultaneous optical analysis for determining the localization of the nanoparticles in glasses of any nature is underlined. Based on the results of a complementary mid-infrared spectroscopy characterization, the processes involved in silver migration to the surfaces and further aggregation to form nanoparticles are discussed.

Fernández Navarro, J. M.; Toudert, J.; Rodríguez-Lazcano, Y.; Maté, B.; de Castro, M. Jiménez

2013-11-01

352

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

353

Structural and optical study of samarium doped lead zinc phosphate glasses  

NASA Astrophysics Data System (ADS)

Samarium doped lead-zinc-phosphate glasses with composition (60-x)P2O5-20PbO-20ZnO-xSm2O3 (x=0, 0.5, 1.0, 3.0 mol%) were prepared by melt quenching technique. Density, refractive index and polaron radius of Sm3+ ions were calculated. The IR spectra reveal significant structural changes only for high concentration of samarium ions. Differential thermal analysis confirms the large structural changes in the glass due to the decrease of thermal stablility in presence of 3 mol% Sm3+ ions. UV-vis-NIR absorption spectroscopy was carried out and Judd-Ofelt analysis was performed. Radiative rates, branching ratio and lifetime of 4G5/2 were calculated by taking into account both electric and magnetic dipole contributions. Absorption spectra consist of seven absorption peaks corresponding to the transitions from the 6H5/2 ground state to various excited energy levels. Photoluminescence spectra show four prominent emission bands centered at 560, 597, 642 and 700 nm corresponding to the 4G5/2-6HJ (J=5/2, 7/2, 9/2, and 11/2) transitions respectively and the intensities of all bands are enhanced by Sm3+ ions content. The calculated values are compared to other reports, available in literature.

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

2013-07-01

354

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

355

The size and structure of Ag particles responsible for surface plasmon effects and luminescence in Ag homogeneously doped bulk glass  

NASA Astrophysics Data System (ADS)

As-prepared and heat-treated oxyfluoride glasses, co-doped with Ag nanoclusters/nanoparticles, are prepared at 0.15 at. % Ag concentration. The as-prepared glass shows an absorption band in the UV/violet attributed to the presence of amorphous Ag nanoclusters with an average size of 1.1 nm. The luminescence spectra of the untreated glass can also be ascribed to these Ag nanoclusters. Upon heat-treatment, the clusters coalesce into Ag nanoparticles with an average size of 2.3 nm, and the glasses show an extra surface plasmon absorption band in the visible. These particles, however, cease to emit due to ascribing plasmonic properties of bulk silver.

Shestakov, M. V.; Meledina, M.; Turner, S.; Tikhomirov, V. K.; Verellen, N.; Rodríguez, V. D.; Velázquez, J. J.; Van Tendeloo, G.; Moshchalkov, V. V.

2013-08-01

356

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

357

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

358

LEACHABILITY OF BORATE-MODIFIED OSB  

E-print Network

;Borate ChemicalsBorate Chemicals · Water Soluble Type Sodium Borate Boric Oxide (B2O3) Boric Acid (H3BO3: A standardized leaching test method for treated wood composites!! #12;Panel Boric Acid Equivalent Analysis #12

359

Fabrication, photoluminescence, and potential application in white light emitting diode of Dy3+-Tm3+ doped transparent glass ceramics containing GdSr2F7 nanocrystals  

NASA Astrophysics Data System (ADS)

Dy3+-Tm3+ doped transparent glass ceramics containing GdSr2F7 nanocrystals were fabricated successfully by a melt-quenching method and subsequent heating. X-ray diffraction and transmission electron microscopy analyses show that tetragonal GdSr2F7 nanocrystals are homogeneously precipitated among the borosilicate glass matrix. If excited with 354 nm UV light, the photoluminescence spectrum of Dy3+ single-doped transparent glass ceramics shows white-light emission. With doping of Tm3+, the overall emission color of Tm3+-Dy3+ co-doped transparent glass ceramics can be tuned from white to blue through energy transfer between Dy3+ and Tm3+. CIE chromaticity and color temperature measurements show that the resulting TGCS may be a candidate as a white LED material pumped by a UV InGaN chip.

Wang, X. F.; Yan, X. H.; Bu, Y. Y.; Zhen, J.; Xuan, Y.

2013-08-01

360

Coarsening kinetics in demixed lead borate melts.  

PubMed

Lead borate melts have been demixed at temperatures in range from 723 to 773 K for times up to 20 h. It is found that increasing time and temperature lead to characteristic changes in the size distribution of boron trioxide drops in the lead-rich glassy matrix (<80.7 mol. % B2O3). The increase of the mean drop size with annealing time followed the cube root time dependence of diffusion controlled coarsening. The diffusivity of the coarsening process was determined using liquid-liquid interfacial energy associated with drop deformation in glass specimens subjected to uniaxial compression. Diffusion coefficients of coarsening were found to match with those of (207)Pb and (18)O tracer ions in the lead borate system but differ up to four orders of magnitude from the Eyring diffusivity and by a factor of ?7 from the activation energy of viscous flow. The results indicate that coarsening in demixed lead borate melts is most likely controlled by the short range dynamics of the interaction between lead cations and BO4 units, which are decoupled from the time scales of cooperative rearrangements of the glassy network at T < 1.1 Tg. PMID:23781800

Dittmar, A; Bornhöft, H; Deubener, J

2013-06-14

361

Role of charge transfer state and host matrix in Eu3+-doped alkali and earth alkali fluoro-aluminoborate glasses  

NASA Astrophysics Data System (ADS)

Judd-Ofelt parameters of Eu3+-doped alkali and earth alkali fluoro-aluminoborate glasses are determined from the fluorescence spectra. The dependence of these parameters on the compositional changes of the materials is discussed. The glass containing sulphate component shows the larger values of ? compared with the fluoro-aluminoborate glasses because of higher ?CT (Eu3+-F-) values. The difference of ionic radius and electronegativity between Na and Ca lead to higher ?2 parameter of CaF2-Al2O3-B2O3:Eu3+ glass. Persistent spectral hole burning has been observed in Eu3+ ions doped alkali-and earth alkali fluoro-aluminoborate glasses with the compositions of 16NaF·73B2O3·8Al2O3·3Eu2O3 and 16CaF2·73B2O3·8Al2O3·3Eu2O3, which have been prepared using conventional melting technique.

Thanh, N. T.; Quang, V. X.; Tuyen, V. P.; Tam, N. V.; Hayakawa, T.; Huy, B. T.

2012-06-01

362

Effect of boron doping on optical properties of sol-gel based nanostructured zinc oxide films on glass  

SciTech Connect

Graphical abstract: Room temperature fine structured UV-vis PL emissions (a) as phonon replicas in 1 at.% boron doped film originated from LO phonon evidenced from Near Grazing Incidence Angle (NGIA) IR spectral study (b). Highlights: Black-Right-Pointing-Pointer Sol-gel based boron doped nanostructured ZnO thin films deposited on pure silica glass using crystalline boric acid as boron source. Black-Right-Pointing-Pointer Observed first time, room temperature fine structured PL emissions in 1 at.% doped film as phonon replicas originated from LO phonon (both IR and Raman active). Black-Right-Pointing-Pointer Boron doping controls the LO phonon energy in addition to visible reflection, band gap and grain size. Black-Right-Pointing-Pointer The films possessed mixed crystal phases with hexagonal as major phase. -- Abstract: Boron doped zinc oxide thin films ({approx}80 nm) were deposited onto pure silica glass by sol-gel dip coating technique from the precursor sol/solution of 4.0 wt.% equivalent oxide content. The boron concentration was varied from 0 to 2 at.% w.r.t. Zn using crystalline boric acid. The nanostructured feature of the films was visualized by FESEM images and the largest cluster size of ZnO was found in 1 at.% boron doped film (B1ZO). The presence of mixed crystal phases with hexagonal as major phase was identified from XRD reflections of the films. Particle size, optical band gap, visible specular reflection, room temperature photoluminescence (PL) emissions (3.24-2.28 eV), infra-red (IR) and Raman active longitudinal optical (LO) phonon vibration were found to be dependent on dopant concentration. For the first time, we report the room temperature fine structured PL emissions as phonon replicas originated from the LO phonon (both IR and Raman active) in 1 at.% boron doped zinc oxide film.

Jana, Sunirmal, E-mail: sjana@cgcri.res.in [Sol-Gel Division, CSIR-Central Glass and Ceramic Research Institute, (Council of Scientific and Industrial Research, CSIR, India), 196 Raja S. C. Mullick Road, Kolkata 700032 (India)] [Sol-Gel Division, CSIR-Central Glass and Ceramic Research Institute, (Council of Scientific and Industrial Research, CSIR, India), 196 Raja S. C. Mullick Road, Kolkata 700032 (India); Vuk, Angela Surca [National Institute of Chemistry, Hajdrihova 19, SI-1000 Ljubljana (Slovenia)] [National Institute of Chemistry, Hajdrihova 19, SI-1000 Ljubljana (Slovenia); Mallick, Aparajita [Sol-Gel Division, CSIR-Central Glass and Ceramic Research Institute, (Council of Scientific and Industrial Research, CSIR, India), 196 Raja S. C. Mullick Road, Kolkata 700032 (India)] [Sol-Gel Division, CSIR-Central Glass and Ceramic Research Institute, (Council of Scientific and Industrial Research, CSIR, India), 196 Raja S. C. Mullick Road, Kolkata 700032 (India); Orel, Boris [National Institute of Chemistry, Hajdrihova 19, SI-1000 Ljubljana (Slovenia)] [National Institute of Chemistry, Hajdrihova 19, SI-1000 Ljubljana (Slovenia); Biswas, Prasanta Kumar [Sol-Gel Division, CSIR-Central Glass and Ceramic Research Institute, (Council of Scientific and Industrial Research, CSIR, India), 196 Raja S. C. Mullick Road, Kolkata 700032 (India)] [Sol-Gel Division, CSIR-Central Glass and Ceramic Research Institute, (Council of Scientific and Industrial Research, CSIR, India), 196 Raja S. C. Mullick Road, Kolkata 700032 (India)

2011-12-15

363

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

364

Third-order optical nonlinearities of silver doped and/or silver-halide modified Ge-Ga-S glasses  

NASA Astrophysics Data System (ADS)

The third-order optical nonlinearities of silver doped and/or silver-halide (AgX, X = Cl, Br, I) modified Ge-Ga-S sulfide glasses are studied by the femtosecond Z-scan method. A general agreement with empirical rules is reached: the nonlinear refractive index scales with the optical bandgap or Sellmeier gap of the samples. However, the AgI-modified glass having a larger linear refractive index than that of AgCl-modified one, exhibits a smaller nonlinear refractive index, in contrary to Miller's rule. This has been explained based on the analysis of the structure of the samples.

Ren, Jing; Li, Bo; Wagner, Tomas; Zeng, Huidan; Chen, Guorong

2014-03-01

365

Effect of Bi2O3 on spectroscopic properties of Er3+ -doped tellurite bismuth glasses for broadband optical amplifiers  

Microsoft Academic Search

The erbium-doped 75TeO2(25-x)ZnO-xBi2O3 glasses have been explored from the density, refractive index, absorption spectra, bandwidth analysis for emission spectra, and lifetime measurements of the 4I13\\/2 level of Er3+ based on Judd-Ofelt and McCumber theories. The effects of bismuth oxide on these three optical parameters Omegat(t=2, 4, 6) are discussed in terms of the local basic nature of the glass. The

Yejiang Shen; Qiu Hua Nie; Tie Feng Xu; Shixun Dai; Xiang Shen

2006-01-01

366

Modeling of optical properties of silver-doped nanocomposite glasses modified by electric-field-assisted dissolution of nanoparticles.  

PubMed

It has been demonstrated recently that silver nanoparticles embedded in a glass matrix can be dissolved by the combination of an intense dc electric field and moderately elevated temperature. In an intermediate state of this process percolated silver layers inside the glass can also occur. These structural modifications significantly modify the optical behavior of the glass, suggesting an interesting perspective for the engineering of optical properties of this kind of metallodielectric materials. We present the optical characterization of silver-doped glasses subjected to the electric-field-assisted dissolution of nanoparticles. The characterization is performed by means of fitting spectrophotometric measurements. The optical properties of the investigated samples are described in terms of the interference between the light reflected from the glass surface and the light reflected from a buried silver-containing layer formed in the depths of the glass. The analysis of the data reveals a porosity of the glass in the region where the nanoparticles are dissolved that can be attributed to the presence of residual nanopores. PMID:17119586

Sancho-Parramon, Jordi; Abdolvand, Amin; Podlipensky, Alexander; Seifert, Gerhard; Graener, Heinrich; Syrowatka, Frank

2006-12-10

367

Upconversion luminescence in Er3+ doped Ga10Ge25S65 glass and glass-ceramic excited in the near-infrared  

NASA Astrophysics Data System (ADS)

The infrared-to-visible frequency upconversion was investigated in Er3+-doped Ga10Ge25S65 glass and in the transparent glass-ceramic obtained by heat-treatment of the glass above its glass-transition temperature. Continuous-wave and pulsed lasers operating at 980 nm and 1480 nm were used as excitation sources. The green (2H11/2 ? 4I15/2; 4S3/2 ? 4I15/2) and red (4F9/2 ? 4I15/2) photoluminescence (PL) signals due to the Er3+ ions were characterized. The PL decay times were influenced by energy transfer among Er3+ ions, by cross-relaxation processes and by energy transfer from the Er3+ ions to the host material. The PL from the Er3+ ions hosted in the crystalline phase was distinguished only when the glass-ceramic was excited by the 1480 nm pulsed laser. The excitation pathways responsible for the green and red PL bands are discussed to explain the differences between the spectra observed under continuous-wave and pulsed excitation.

Lozano B., Whualkuer; de Araújo, Cid B.; Ledemi, Yannick; Messaddeq, Younes

2013-02-01

368

Preparation of small-particle-size, semiconductor CdS-doped silica glasses by the sol-gel process  

SciTech Connect

The sol-gel process has been applied successfully to the preparation of small-particle-size CdS-doped silica glasses with a significant quantum size effect. Gels prepared through the hydrolysis of a complex solution of Si(OC{sub 2}H{sub 5}){sub 4} and Cd(CH{sub 3}COO){sub 2} {center dot} 2H{sub 2}O were heated at 500{degrees}C, then reacted with H{sub 2}S gas to form fine, hexagonal, CdS-microcrystal-doped glasses. The optical absorption edge is blue shifted by {approximately}0.4 eV compared with the bulk absorption value of CdS crystal. This results is interpreted in terms of a quantum-confinement effect of small crystal size.

Nogami, M.; Nagaska, K.; Kato, E. (Department of Applied Chemistry, Aichi Institute of Technology, 1247-03 (JP))

1990-07-01

369

Synthesis and visible light photocatalysis of Fe-doped TiO 2 mesoporous layers deposited on hollow glass microbeads  

NASA Astrophysics Data System (ADS)

Nano-composite of Fe-doped anatase TiO 2 nanocrystals loaded on the hollow glass microbeads was prepared by co-thermal hydrolysis deposition and calcining treatment. The adherence of TiO 2 mesoporous layers to the surfaces of hollow glass microbeads prevented the aggregation of TiO 2 nanoparticles and benefited to their catalytic activity. The doping of Fe ions makes the absorption edge of the TiO 2 based nano-composite red-shifted into the visible region. An effective photodegradation of the methyl orange aqueous solution was achieved under visible light ( ?>420 nm) irradiation, revealing the potential applicability of such nano-composite in some industry fields, such as air and water purifications.

Cui, Lifeng; Wang, Yuansheng; Niu, Mutong; Chen, Guoxin; Cheng, Yao

2009-10-01

370

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

371

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

372

Optical characterization of Fe and Cu-doped SiO2 glasses prepared by the sol-gel method  

Microsoft Academic Search

The SiO2 glasses obtained by the sol-gel process, doped with Fe or Cu and annealed either at oxidizing or at reducing (CO - CO2) atmosphere, exhibit deep coloring caused by the absorption and scattering bands in the visible spectral region followed by a considerable change of the shape of the infra-red absorption bands in the region 1000 - 1250 cm-1

Juan F. Perez-Robles; Francisco J. Rodriguez; Jesus Gonzalez-Hernandez; Sergio Jimenez-Sandoval; Yuri V. Vorobiev; Alejandro Manzano-Ramirez; Martin Yanez-Limon; Roman V. Zakharchenko

1998-01-01

373

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

374

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

375

Investigation of thermal stability and spectroscopic properties in Er3+/Yb3+ co-doped niobic tungsten tellurite glasses.  

PubMed

A series of novel Er3+/Yb3+ co-doped 75TeO2-(25-x)Nb2O5-xWO3 (TNW: x=0, 3, 6, 9, 12, and 15 mol%) glasses have been prepared. Effect of WO3 on the thermal stability and spectroscopic properties of Er3+/Yb3+ co-doped niobic tellurite glasses have been investigated. With WO3 content increasing from 0 to 15 mol%, the fluorescence full width at half maximum (FWHM), the peak of stimulated emission cross-section (sigmaepeak), the measured lifetime (taum), and quantum efficiency (eta) change from 71 nm, 8.47x10(-21) cm2, 2.86 ms, 84.1% to 76 nm, 7.22x10(-21) cm2, 3.14 ms, 88.9%, respectively. The FWHM and sigmaepeak of Er3+ ions in different glass hosts were compared; the obtained data reveals that this new TNW4 glass may be a potentially useful candidate material host for broadband amplifiers. PMID:17988941

Wang, Xuming

2008-06-01

376

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

377

White light emission from Dy3+ doped sodium-lead borophosphate glasses under UV light excitation  

NASA Astrophysics Data System (ADS)

Sodium-lead borophosphate glasses doped with different Dy3+ concentrations have been prepared and characterized through, XRD, FTIR, optical absorption and photoluminescence techniques. FTIR spectrum indicates the presence of BO3 and PO4 structural units. The optical absorption spectrum has been studied at room temperature and several bands have been observed. These bands have been assigned to the ground state 6H15/2 to several excited states. The bonding parameters have been evaluated based on the observed band positions. From the absorption spectrum, Judd-Ofelt (J-O) intensity parameters have been evaluated. By using J-O parameters radiative parameters such as transition probabilities, branching ratios and absorption cross section have been evaluated. The emission spectra have been studied for different concentrations of Dy3+ ions. The yellow/blue values due to 4F9/2 ? 6H13/2/4F9/2 ? 6H15/2 luminescence intensity ratios of Dy3+ ions, increase with increasing concentrations, suggesting higher asymmetry and more covalent bonding character between Dy and oxygen ligands. The chromaticity coordinates were calculated from emission spectra and analysed with Commission International deI'Eclarige Color diagram. The life time of the 4F9/2 level has been measured and found to decrease with increase in Dy3+ ions concentration.

Kiran, N.; Suresh Kumar, A.

2013-12-01

378

Brillouin spectroscopy of a novel baria-doped silica glass optical fiber.  

PubMed

Presented here for the first time to the best of our knowledge is a detailed Brillouin spectroscopic study of novel, highly-BaO-doped silica glass optical fibers. The fibers were fabricated utilizing a molten-core method and exhibited baria (BaO) concentrations up to 18.4 mole %. Physical characteristics such as mass density, acoustic velocity, visco-elastic damping, and refractive index are determined for the baria component of the bariosilicate system. It is found that, of each of these parameters, only the acoustic velocity is less than that of pure silica. The effect of temperature and strain on the acoustic velocity also is determined by utilizing estimates of the strain- and thermo-optic coefficients. The dependencies are found to have signs opposite to those of silica, thus suggesting both Brillouin-frequency a-thermal and a-tensic binary compositions. Via the estimate of the strain-optic coefficient and data found in the literature, the Pockels' photoelastic constant p(12) is estimated, and both a calculation and measured estimate of the Brillouin gain versus baria content are presented. Such novel fibers incorporating the unique properties of baria could be of great utility for narrow linewidth fiber lasers, high power passive components (such as couplers and combiners), and Brillouin-based sensor systems. PMID:23669949

Dragic, P; Kucera, C; Furtick, J; Guerrier, J; Hawkins, T; Ballato, J

2013-05-01

379

Photoluminescence and energy transfer properties of Sm 3+ doped CFB glasses  

NASA Astrophysics Data System (ADS)

The present paper describes the optical absorption, photoluminescence and lifetime measurements of trivalent samarium doped calcium fluoroborate (CFB) glasses. From the observed energy levels, the free-ion energy level parameters for the 4f 5 electronic configuration of Sm 3+ ion have been evaluated using H FI model. The experimental oscillator strengths of absorption bands have been analyzed to determine the Judd-Ofelt (J-O) parameters. From the evaluated J-O parameters and luminescence data, the radiative parameters such as AR, ?R and ?e values were obtained from the excited 4G 5/2 level to different lower energy levels. The decay curves of 4G 5/2 ? 6H 7/2 transition were analyzed by the Inokuti-Hirayama model assuming dipole-dipole interaction between the dopant ions. The decrease of fluorescence intensities as well as measured lifetimes at higher concentrations has been explained based on energy transfer process through cross-relaxation between Sm 3+ ions.

Suresh Kumar, J.; Pavani, K.; Sasikala, T.; Sreenivasa Rao, A.; Giri, Neeraj Kumar; Rai, S. B.; Rama Moorthy, L.

2011-08-01

380

Optical Investigation of Sm3+ Doped Zinc-Lead-Phosphate Glass  

NASA Astrophysics Data System (ADS)

Samarium doped lead-zinc-phosphate glasses having composition (60-x)P2O5-20PbO-20ZnO-xSm2O3 where x=0, 0.5, 1.0, 3.0mol% were prepared by using the melt quenching technique. The Archimedes method was used to measure their densities, which are used to calculate the molar volumes. The values of densities lie in the range 3.698-4.090 gm/cm3 whereas those of molar volume lie in the range of 37.24-40.00 cm-3. UV-vis-NIR absorption spectroscopy in the wavelength range 200-2000 nm was carried out. Absorption spectra consist of seven absorption peaks corresponding to the transitions from the 6H5/2 ground state to various excited energy levels. The energy band gap measured from the optical absorbance is found to be in the range of 3.88-4.43 eV and 3.68-4.33 eV for direct and indirect transitions, respectively. In addition, the photoluminescence spectrum shows four prominent emission bands centered at 560, 597, 642 and 700 nm corresponding to the 4G5/2-6HJ (J=5/2, 7/2, 9/2, 11/2) transitions respectively and the intensity of all the bands are enhanced as the concentration of Sm3+ ions increases.

Raja, J. Amjad; R. Sahar, M.; K. Ghoshal, S.; R. Dousti, M.; Riaz, S.; A. Tahir, B.

2012-08-01

381

The spectroscopic properties of Er 3+-doped TeO 2–Nb 2O 5 glasses with high mechanical strength performance  

Microsoft Academic Search

(100?x)TeO2?xNb2O5 (x=5–20) niobic tellurite glasses doped with 0.5mol.% Er2O3 were synthesized, and their thermal, mechanical, and spectroscopic properties were measured and compared to the properties of the typical 75TeO2–20ZnO–5Na2O (TZN) tellurite glass. The refractive index (nd), density (?), and glass transition temperature (Tg) of bulk glasses increase with the Nb2O5 content. The Vickers microhardness (Hv) of bulk glass in niobic

Shixun Dai; Jialu Wu; Junjie Zhang; Guonian Wang; Zhonghong Jiang

2005-01-01

382

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

383

Spectrum upconversion and downconversion in (Tm3+,Yb3+) and (Tb3+,Yb3+) co-doped fluorosilicate glass  

NASA Astrophysics Data System (ADS)

We investigated the upconversion and downconversion luminescence in (Tb3+, Yb3+) and (Tb3+, Yb3+) co-doped lithiumlanthanum- aluminosilicate oxyfluoride glass. Upon excitation at 980 nm, where crystalline CdTe solar cells no longer absorb, the sub-bandgap photons can be converted to the higher-energy ones via upconversion. In addition, under excitation between 470 nm and 490 nm, one blue photon might be split up to two near-infrared ones via downconversion. The downconversion luminescence matches the spectral response of crystalline Si solar cell well. We observed much more intense upconversion luminescence from (Tm3+, Yb3+) codoped glass than that from ( Tb3+, Yb3+) codoped glass under the same 980 nm excitation conditions. Our results indicate that the sequential energy transfer from Yb3+ ions to Tm3+ ions is much more efficient than the cooperative energy transfer from Yb3+ ions to Tb3+ ions.

Pan, Z.; Akrobetu, R.; Morgan, S. H.

2013-09-01

384

UV-visible and infrared absorption spectroscopic studies of gamma irradiated tungsten-doped lithium phosphate glasses  

NASA Astrophysics Data System (ADS)

Ultraviolet-visible and infrared spectroscopic techniques were employed to investigate the undoped lithium phosphate glass and other samples of the same composition doped with varying WO3 contents. The same spectroscopic properties were remeasured after subjecting the samples to 3 and 6 Mrad doses of gamma irradiation on the measured properties. Such combined analytical techniques are expected to give information about the state of tungsten ions in such lithium phosphate glass and justify the effect of gamma irradiation. The work aims to deduce the radiation-induced defects generated through successive gamma irradiation by optical measurements. Also, the study is expected to realize through IR spectroscopy, the main structural building groups and the influence of tungsten ions within the structural vibrational groups of the studied glasses.

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

2011-11-01

385

Controllable gamma-ray sensitivity of Ag-doped and/or AgI-modified Ge-Ga-S glasses  

NASA Astrophysics Data System (ADS)

Gamma-ray (?-ray) sensitivity has been studied in Ag-doped and/or AgI-modified Ge-Ga-S glasses. The sensitivity is controllable in terms of silver presence. Compared to the silver-free sample, the AgI-modified glass shows greater sensitivity to ?-ray irradiation regarding larger change in the transmission spectra (?T), whereas improved resistance to ?-ray irradiation occurs in the silver-doped AgI-modified glass with only 1 mol% silver metal being intentionally added.

Shen, Wei; Ren, Jing; Chen, Guorong; Baccaro, Stefania; Cemmi, Alessia; di Sarcina, Ilaria; Falconieri, Mauro; Menchini, Francesca

2012-06-01

386

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

387

Elucidation of coordination structure around Ce3+ in doped SiO2 glasses using pulsed electron paramagnetic resonance: Effect of phosphorus, boron, and phosphorus-boron codoping  

NASA Astrophysics Data System (ADS)

Effects of codoping of phosphorus and/or boron on the coordination sphere of a Ce3+ in SiO2 glasses were examined by applying pulsed electron paramagnetic resonance (EPR) electron spin echo envelope modulation (ESEEM) spectroscopy. Simulation of the observed ESEEM pattern revealed a striking difference in the solvation shell structure between the P-doped and the P-free glasses, i.e., the P doping is very effective for the formation of the solvation shell, while no such an effect was observed for the B doping. When P and B are simultaneously doped, the solvation shell structure is close to that in the P-doped samples. Photoluminescence properties of Ce3+ in these samples were found to be classified into two categories corresponding to the solvation shell structures.

Saitoh, Akira; Matsuishi, Satoru; Oto, Masanori; Miura, Taisuke; Hirano, Masahiro; Hosono, Hideo

2005-12-01

388

Color-tunable emission and energy transfer in Tm3+/Dy3+/Sm3+ tri-doped phosphate glass for white light emitting diodes  

NASA Astrophysics Data System (ADS)

Re3+ (Re3+=Tm3+, Dy3+, Sm3+) ions doped phosphate glasses for white light emitting diodes (W-LEDs) are successfully prepared by the high-temperature melting method. The luminescence properties of the glasses were characterized by the emission and excitation spectra. When excited by ultraviolet light Tm3+ ions single doped, Dy3+ ions single doped, and Sm3+ ions single doped phosphate glass emit blue, green and red light, which give the characteristic transitions of Tm3+ ions (1D2?3F4), Dy3+ ions (4F9/2?6H13/2,15/2), and Sm3+ ions (4G5/2?6H7/2,9/2), respectively. Moreover, there exists simultaneous luminescence of Tm3+, Dy3+, Sm3+ ions individually when co-doping them in the single phased phosphate glass (for example, Tm3+/Sm3+ ions co-doped; Dy3+/Sm3+ ions co-doped; Dy3+/Tm3+ ions co-doped; Tm3+/Dy3+/Sm3+ ions tri-doped systems), which is beneficial to tune the emission colors. Under the 360 nm excitation, the CIE coordinates of Tm3+/Dy3+/Sm3+ ions tri-doped samples are close to the standard equal energy white light illumination (x=0.333, y-0.333). With an increasing in Sm3+ ions concentration, blue and green emissions decrease gradually while red emission increases. In addition, the energy transitions among Tm3+, Dy3+, and Sm3+ ions are discussed in detail. The phenomenon is reasonably interpreted based on the analysis of the luminescence lifetime.

Yu, Yin; Song, Feng; Ming, Chengguo; Liu, Jiadong; Li, Wei; Liu, Yanling; Zhao, Hongyan

2013-08-01

389

An optical and structural investigation into CdTe nanocrystals embedded into the tellurium lithium borophosphate glass matrix  

NASA Astrophysics Data System (ADS)

Cadmium telluride nanocrystals that form in the TeO2-Li2O-B2O3-P2O5 glass matrix have been synthesized and studied. They are investigated by X-ray diffraction (XRD), optical transmission and infrared spectroscopy. It has been shown that the long annealing time effect on present samples leads to the growth of CdTe nanoparticles and an increase of tellurium oxide on the surface of nanocrystallites. On the other hand, the infrared spectroscopy shows that the phosphate and borate networks of the glass matrices are modified with doping by CdTe nanoparticles.

Wageh, S.; Zhao, Suling; Xu, Zheng

2010-05-01

390

NMR Studies of Magnetic and Fast Ionic Conducting Amorphous Borates.  

NASA Astrophysics Data System (ADS)

NMR studies were performed on lead borate glasses containing significant concentrations of Fe(,2)O(,3) and on lithium borate glasses containing lithium halides (LiCl or LiF). ('11)B and ('207)Pb NMR investigations of glasses in the system x Fe(,2)O(,3)(.)y PbO(.)z B(,2)O(,3) (0 (LESSTHEQ) x (LESSTHEQ) 15.3 Mol %, z/y (DOT=) 3) revealed that the NMR line broadening contains Gaussian field-independent and field-dependent components, and field-dependent Lorentzian components, resulting in broadening lineshapes of the Voight type. The ('11)B NMR linewidth data were in excellent agreement with a model which assumes the Fe atoms are distributed uniformly and isotropically throughout the glass matrix, and suggests the absence of significant concentrations of B-Fe linkages in these glasses. While the ('11)B NMR linewidth and magnetic susceptibility data vary smoothly and monotonically over the sample composition range, the density, N(,4) (fraction of 4-coordinated borons), and ('207)Pb NMR absorption peak position display evidence of two-region behavior with the break between regions near 4 Mol % Fe(,2)O(,3). The NMR data is interpreted in terms of changes in the borate network. The results of N(,4) and ('11)B NMR lineshape measurement performed on the fast ionic conducting lithium flouroborate (Li(,2)O-Li(,2)F(,2)-B(,2)O(,3)) and lithium chloroborate (Li(,2)O-Li(,2)Cl(,2)-B(,2)O(,3)) glass systems were found to be in excellent agreement with a model which assumes that the types and quantities of borate configurations present in the glasses are totally unaffected by the presence of the lithium halide species. The model employs a semi -empirical theory of the borate network developed for the binary Li(,2)O-B(,2)O(,3) system and predicts that N(,4) should depend entirely on R = Mol % Li(,2)O)/(Mol % B(,2)O(,3)). This agreement suggests that the lithium halide enters the glass network interstitially.

Bucholtz, Frank

391

Preparation and optical characteristics of ZnSe nanocrystals doped glass by sol gel in situ crystallization method  

NASA Astrophysics Data System (ADS)

Homogeneous ZnSe nanocrystals doped SiO 2 glass was successfully prepared by sol-gel in situ crystallization method. The structure of the doped ZnSe nanocrystals was studied by X-ray diffraction (XRD). ZnSe nanocrystals in silica were about 4-10 nm analysed by transmission electron microscopy (TEM), which was consistent with the results of XRD estimated using Scherrer's formular. The quantum size effect in ZnSe nanocrystals was evidenced from the blue-shifts of the optical absorption edge, and the average size of ZnSe nanocrystals was estimated by the magnitude of blue shift according to the L.E. Brus' effective mass model. The size of ZnSe nanocrystals depending on annealing time and temperature was further discussed using XRF.

Hao, Haiyan; Yao, Xi; Wang, Minqiang

2007-01-01

392

Composition-induced valence variation of europium and the photoluminescence properties for Eu2+ doped borophosphate luminous glass in air  

Microsoft Academic Search

A simultaneous blue-light and red-light emitting glass of SrO-B2O3-P2O5 doped with Eu2O3 is prepared in air, and then heat-treated without any reductive reagent. A transition combination is found to consist of a band emission peaked around 430 nm and a series of line emission from 593 nm to 611 nm, corresponding to the typical 4f6-->5d 4f7 transition of Eu2+ and

Kun Qiu; Suo-Cheng Xu; Hua Tian; Xi Zheng; Tian-Shuai Lv; Qi-Fei Lu; Da-Jian Wang

2011-01-01

393

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

394

Composition-induced valence variation of europium and the photoluminescence properties for Eu2+ doped borophosphate luminous glass in air  

NASA Astrophysics Data System (ADS)

A simultaneous blue-light and red-light emitting glass of SrO-B2O3-P2O5 doped with Eu2O3 is prepared in air, and then heat-treated without any reductive reagent. A transition combination is found to consist of a band emission peaked around 430 nm and a series of line emission from 593 nm to 611 nm, corresponding to the typical 4f6?5d 4f7 transition of Eu2+ and 5D0?7F J ( J = 0, 1, 2, 3, 4) transitions of Eu3+, respectively. Some unidentified crystals such as Sr (PO3)2 and SrB2O4 as hosts for Eu2+ with more stronger crystal field lead to this enhancement of photoluminescence (PL) intensity superior to the asprepared parent glass.

Qiu, Kun; Xu, Suo-Cheng; Tian, Hua; Zheng, Xi; Lv, Tian-Shuai; Lu, Qi-Fei; Wang, Da-Jian

2011-09-01

395

Color tuning of Eu-Tb co-doped borophosphate glasses for white light through valence state adjustment  

NASA Astrophysics Data System (ADS)

The dependence of color points of white light on the composition of borophosphate glasses co-doped with europium (Eu) and terbium (Tb) has been investigated in terms of valence change of rare earth ions. Under ultraviolet (UV) excitation, the white light is observed to be from a combination of 4f65d ? 4f7 band transition emission at 425 nm for Eu2+, 5D0 ? 7F J ( J=1, 2) line-emissions at 593 nm and 611 nm for Eu3+, and 5D4 ? 7F5 band transition emission at 545 nm for Tb3+. By varying the glass composition, the resultant emission color can be tuned efficiently. Eventually, the optimized white light with commission international de I'Eclairage (CIE) coordinate of (0.3382, 0.2763) and the correlate color temperature (CCT) at 5010 K are achieved.

Xu, Suo-Cheng; Zheng, Xi; Tian, Hua; Lv, Tian-Shuai; Wang, Peng; Wang, Da-Jian

2011-11-01

396

The effect of La2O3 in Tm3+-doped germanate-tellurite glasses for ~2??m emission  

NASA Astrophysics Data System (ADS)

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.

Peng, Ya-Pei; Yuan, Xinqiang; Zhang, Junjie; Zhang, Long

2014-06-01

397

Tm3+-doped tellurite glasses for fiber amplifiers in broadband optical communication at 1.20 µm wavelength region.  

PubMed

Broadband emissions at around 1.20 and 1.46 ?m wavelengths from thulium (Tm(3+))-doped tellurite glasses were observed under 465 nm wavelength excitation. The 1.20 ?m emission originates from the Tm(3+): (1)G(4)-->(3)H(4) transition, and the associated stimulated peak emission cross-section is calculated to be 0.47 × 10(-20) cm(2). Population inversion occurs between the (1)G(4) and (3)H(4) levels, and a positive gain band from 1.20 to 1.28 ?m is achieved at relatively low Tm(3+) dopant concentration. Our results suggest that this glass system is promising for optical fiber amplifiers operating at the relatively unexplored low loss 1.20 ?m wavelength region. PMID:20940773

Zhou, Bo; Lin, Hai; Pun, Edwin Yue-Bun

2010-08-30

398

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

399

Effect of natural Fe3O4 nanoparticles on structural and optical properties of Er3+ doped tellurite glass  

NASA Astrophysics Data System (ADS)

Control doping of magnetic nanoparticles and its influence on optical and structural properties of tellurite glass is important from device perspectives. Natural Fe3O4 nanoparticles obtained by extracting and ball milling iron sand, are incorporated in the Er3+ doped tellurite glasses having composition (80-x)TeO2·xFe3O4·18ZnO·1Li2O·1Er2O3 (0?x?1.5) in mol% by melt quenching method at 850 °C. X-Ray diffraction spectra confirms the presence of iron nanoparticles with estimated sizes 18-70 nm and an amorphous structure of the samples. Thermal and optical characterizations are made using diffential thermal analysis, ultraviolet-visible and photoluminescence spectrocopies. It is found that the presence of nanoparticles changes color and thermal stability of the glasses, which is proved by increasing thermal stability factor from 118 to 132 °C. Absorption spectra consist of six peaks corresponding to different transition from ground state to the excited states in which the quench of the peak associated with 4F1/2 is attributed to the effect nanoparticles. Moreover, the shift in the absorption edge from ?400 to ?500 nm indicates a significant decrease of the optical energy band gap for both direct and indirect allowed transitions and a decrease in the Urbach energy as much as 0.116 eV is observed. The room temperature down-conversion luminescence spectra obtained under 500 nm excitation exhibit two strong peaks related to excited states 4S3/2 and 4F9/2 of Er3+ ions in the absence of nanoparticles. Furthermore, embedding nanoparticles into the glass not only make the peaks weaker but the second peak completely disappears. Interestingly, the emission bands of the Er3+ ion are quenched as concentration of the magnetic nanoparticles is increased.

Widanarto, W.; Sahar, M. R.; Ghoshal, S. K.; Arifin, R.; Rohani, M. S.; Hamzah, K.

2013-01-01

400

Thermal properties and optical transition probabilities of Tm3 + doped TeO2-WO3 glass.  

PubMed

Glasses with the composition of (1 - x)TeO2 + (x)WO3, where x = 0.15, 0.25 and 0.3 were prepared and, their thermal and absorption measurements were carried out. Differential thermal analysis (DTA) curves taken in the 23-600 degrees C temperature range with a heating rate of 10 degrees C/min reveal a change in the value of the glass transition temperature, Tg, while crystallization was not observed for the glasses containing a WO3 content of more than 15 mol%. All the glasses were found to be moisture-resistant. The absorption bands corresponding to the absorption of the 1G4, 3F2, 3F3 and 3F4, 3H5 and 3H4 levels from the 3H6 ground level of the Tm3+ ion were observed in the optical absorption spectra. Integrated absorption cross-sections of each band except that of 3H5 level was found to vary with the glass composition. Judd-Ofelt analysis was carried out for the samples doped with 1.0 mol% Tm2O3. The omega2 parameter shows the strongest dependence on the host composition and it increases with the increasing WO3 amount. The value of omega4 increases rather slowly while the value of omega6 is practically independent of the composition. The strong dependence of the parameter omega2 indicates that this parameter is related to the structural change and the symmetry of the local environment of the Tm3+ ions in this glass. PMID:11767831

Cenk, S; Demirata, B; Oveçoglu, M L; Ozen, G

2001-10-01

401

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

402

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

403

Thermal neutron detection with the lithium borate scintillator  

Microsoft Academic Search

Single crystals of 6Li158Gd(11B 3O)3 were grown, then powdered and mixed with powdered Schott glass and epoxy. The dough was solidified in a Teflon mold to a scintillator foil of 3 mm thickness and size 50 mm×50 mm. By attaching the 6Li borate foil to a conventional RCA photo multiplier (PM) and to a position sensitive Hamamatsu PM the properties

R. Engels; R. Reinartz; J. Schelten; B. Czirr

1999-01-01

404

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

405

Surface silver-doping of biocompatible glasses to induce antibacterial properties. Part II: plasma sprayed glass-coatings  

Microsoft Academic Search

A 57% SiO2, 3% Al2O3, 34% CaO and 6% Na2O glass (SCNA) has been produced in form of powders and deposited by plasma spray on titanium alloy and stainless steel substrates.\\u000a The obtained coatings have been subjected to a patented ion-exchange treatment to introduce silver ions in the surface inducing\\u000a an antibacterial behavior. Silver surface-enriched samples have been characterized by

M. Miola; S. Ferraris; S. Di Nunzio; P. F. Robotti; G. Bianchi; G. Fucale; G. Maina; M. Cannas; S. Gatti; A. Massé; C. Vitale Brovarone; E. Verné

2009-01-01

406

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

407

Fabrication and characterization of new Er 3+ doped niobium borophosphate glass fiber  

Microsoft Academic Search

Optical fibers are drawn from niobium borophosphate preforms and characterized by Raman and micro-luminescence spectroscopy. Un-doped and erbium doped materials have been investigated. Raman spectroscopy has been used to characterize the structure of the preform and of the fiber. The spectra show that the fiber exhibits the same structure as the preform while no crystallization could be detected. This result

L. Petit; T. Cardinal; J. J. Videau; F. Smektala; T. Jouan; K. Richardson; A. Schulte

2005-01-01

408

Structure of AgI-doped Ge-In-S glasses: Experiment, reverse Monte Carlo modelling, and density functional calculations  

SciTech Connect

We report an investigation of the structure and vibrational modes of Ge-In-S-AgI bulk glasses using X-ray diffraction, EXAFS spectroscopy, Reverse Monte-Carlo (RMC) modelling, Raman spectroscopy, and density functional theoretical (DFT) calculations. The combination of these techniques made it possible to elucidate the short- and medium-range structural order of these glasses. Data interpretation revealed that the AgI-free glass structure is composed of a network where GeS{sub 4/2} tetrahedra are linked with trigonal InS{sub 3/2} units; S{sub 3/2}Ge-GeS{sub 3/2} ethane-like species linked with InS{sub 4/2}{sup -} tetrahedra form sub-structures which are dispersed in the network structure. The addition of AgI into the Ge-In-S glassy matrix causes appreciable structural changes, enriching the Indium species with Iodine terminal atoms. The existence of trigonal species InS{sub 2/2}I and tetrahedral units InS{sub 3/2}I{sup -} and InS{sub 2/2}I{sub 2}{sup -} is compatible with the EXAFS and RMC analysis. Their vibrational properties (harmonic frequencies and Raman activities) calculated by DFT are in very good agreement with the experimental values determined by Raman spectroscopy. - Graphical abstract: Experiment (XRD, EXAFS, RMC, Raman scattering) and density functional calculations are employed to study the structure of AgI-doped Ge-In-S glasses. The role of mixed structural units as illustrated in the figure is elucidated. Highlights: Black-Right-Pointing-Pointer Doping Ge-In-S glasses with AgI causes significant changes in glass structure. Black-Right-Pointing-Pointer Experiment and DFT are combined to elucidate short- and medium-range structural order. Black-Right-Pointing-Pointer Indium atoms form both (InS{sub 4/2}){sup -} tetrahedra and InS{sub 3/2} planar triangles. Black-Right-Pointing-Pointer (InS{sub 4/2}){sup -} tetrahedra bond to (S{sub 3/2}Ge-GeS{sub 3/2}){sup 2+} ethane-like units forming neutral sub-structures. Black-Right-Pointing-Pointer Mixed chalcohalide species (InS{sub 3/2}I){sup -} offer vulnerable sites for the uptake of Ag{sup +}.

Chrissanthopoulos, A. [Foundation for Research and Technology Hellas, Institute of Chemical Engineering and High Temperature Chemical Processes (FORTH/ICE-HT), PO Box 1414, Patras, GR-26504 (Greece); Jovari, P. [Research Institute for Solid State Physics and Optics, Hungarian Academy of Sciences, PO Box 49, Budapest, H-1525 (Hungary); Kaban, I. [IFW Dresden, Institute for Complex Materials, PO Box 270116, Dresden, D-01171 (Germany); Gruner, S. [Chemnitz University of Technology, Institute of Physics, D-09107, Chemnitz (Germany); Kavetskyy, T. [Solid-State Microelectronics Laboratory, Drohobych Ivan Franko State Pedagogical University, 24 I.Franko Str., Drohobych 82100 (Ukraine); Borc, J. [Department of Applied Physics, Lublin University of Technology, 38 Nadbystrzycka Str., Lublin 20-618 (Poland); Wang, W.; Ren, J.; Chen, G. [School of Materials Science and Engineering, East China University of Science and Technology, 130 Meilong Road, Shanghai 200237 (China); Yannopoulos, S.N., E-mail: sny@iceht.forth.gr [Foundation for Research and Technology Hellas, Institute of Chemical Engineering and High Temperature Chemical Processes (FORTH/ICE-HT), PO Box 1414, Patras, GR-26504 (Greece)

2012-08-15

409

Spectroscopic properties and near-infrared broadband luminescence of Bi-doped SrB4O7 glasses and crystalline materials.  

PubMed

Spectroscopic properties of Bi-doped SrB(4)O(7) glasses, sintered compounds, polycrystalline materials, and single crystals were investigated. Broadband near-infrared luminescence was realized in Bi-doped SrB(4)O(7) glasses with basicity and polycrystalline materials with non-bridging oxygens. In Bi:SrB(4)O(7) single crystals, only visible luminescence of Bi(3+) and Bi(2+) was observed, but no near-infrared. The rigid three-dimensional network of SrB(4)O(7) crystal is proved to be unfavorable for accommodation of Bi(+) ions. PMID:19654763

Su, Liangbi; Zhou, Peng; Yu, Jun; Li, Hongjun; Zheng, Lihe; Wu, Feng; Yang, Yan; Yang, Qiuhong; Xu, Jun

2009-08-01

410

Thermal lens study of thermo-optical properties and concentration quenching of Er{sup 3+}-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 Er{sup 3+}-doped lead pyrophosphate-based glasses. More precisely, we have investigated and quantified experimentally the fluorescence quantum efficiencies of the Er{sup 3+} levels, and we describe the role of concentration quenching effects. The fluorescence quantum efficiency of the {sup 4}I{sub 13/2} level is very high when compared to other phosphate glasses, while that of the green-coupled levels is very small. Other important photonic materials parameters, such as the thermal diffusivity and temperature coefficient of the optical path length change, were obtained and compared with those of other glass systems. The cumulative results obtained here for the Er-doped lead pyrophosphate glass show that this material is a good candidate for photonic applications with a characteristic Er{sup 3+} infrared emission around 1550 nm.

Santos, C. C. [Departamento de Fisica, CCET, Universidade Federal do Maranhao, 65085-580 Sao Luis-MA (Brazil); Rocha, U.; Vermelho, M. V. D.; Jacinto, C. [Grupo de Fotonica e Fluidos Complexos, Instituto de Fisica, Universidade Federal de Alagoas, 57072-970 Maceio, AL (Brazil); Guedes, I. [Departamento de Fisica, Universidade Federal do Ceara, Campus do PICI, Caixa Postal 6030, 60455-760 Fortaleza, CE (Brazil); Boatner, L. A. [ORNL Center for Radiation Detection Materials and Systems and ORNL Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831-6044 (United States)

2012-06-15

411

TiO?-doped phosphate glass microcarriers: a stable bioactive substrate for expansion of adherent mammalian cells.  

PubMed

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% TiO? 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; Wall, Ivan B

2013-07-01

412

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