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1

Optical properties of Eu 3+-doped zinc borate glasses  

Microsoft Academic Search

Photoluminescence, absorption and optical excitation spectra of undoped and Eu3+-doped binary zinc borate glasses of varied composition prepared by the melt quenching technique in air atmosphere were investigated. From photoluminescence measurements it was found that growing Eu3+ concentration leads to gradual disappearance of the broadband glass emission in the near-UV spectral range, while the red Eu3+ emission at 613nm shows

A. Ivankov; J. Seekamp; W. Bauhofer

2006-01-01

2

Devitfrification Properties Of Bismuth Borate Glasses Doped With Trivalent Ions  

NASA Astrophysics Data System (ADS)

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: xBi2O3-(100-×)B2O3 (x = 20, 25, 30, 37.5, 40, 50, 60 and 66 mol %) and 40Bi2O3-1Tv2O3-59B2O3 (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. Bi3B5O12 was found to be the predominant phase in all crystallized samples containing Bi2O3 concentration of <=40 mol %, at higher Bi2O3 concentration, we observed the formation of Bi4B2O9 phase. Glasses with Bi2O3 concentration of <=37.5 mol % produced Bi2B8O15 phase on crystallization. The metastable BiBO3-I phase was formed by short duration heat treatment (less than 5 hours) of the initial glass sample. Doping with rare earth ions like Eu3+ and Nd3+ promotes the formation of BiBO3-II phase while Al3+ doping suppresses it.

Khanna, Atul; Bajaj, Anu

2010-12-01

3

Infrared spectra of zinc doped lead borate glasses  

Microsoft Academic Search

The infrared spectra of zinc-doped lead borate glasses (10–30 mol% ZnO) were measured over a continuous spectral range (400–4000\\u000a cm?1) in an attempt to study their structure systematically. No boroxol ring formation was observed in the structure of these\\u000a glasses. The formation of Zn in tetrahedral coordination was not observed. The conversion of three-fold to four-fold coordinated\\u000a boron took place.

S. G. Motke; S. P. Yawale; S. S. Yawale

2002-01-01

4

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

5

Optical properties of Dy3+ doped bismuth zinc borate glass and glass ceramics  

NASA Astrophysics Data System (ADS)

Dy3+ doped bismuth zinc borate transparent glasses were prepared by melt quenching technique and these glasses were used precursor to obtain transparent glass ceramics by heat treatment method. XRD pattern of the glass ceramic shows the formation of the ?-BiB3O6 and Bi2ZnOB2O6 phases. The visible emission intensity of the glass ceramics is stronger than the glass. This can be due to the formation of nano nonlinear optical crystallites in glass matrix.

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

2012-06-01

6

Spectroscopic investigation of zinc borate glasses doped with trivalent europium ions  

Microsoft Academic Search

4ZnO · 3B2O3 glasses undoped and doped with 0.5–2.5% Eu3+ were studied using absorption, emission and excitation spectroscopies, fluorescence line narrowing, Raman scattering and lifetime measurements. The vibrational spectra of the undoped and doped glasses are very similar and indicate the presence of borate groups already observed in binary metaborate glasses. The Judd-Ofelt parameters and the asymmetry ratio derived from

M. Bettinelli; A. Speghini; M. Ferrari; M. Montagna

1996-01-01

7

Optical characterization of Eu 3+ and Tb 3+ ions doped zinc lead borate glasses  

Microsoft Academic Search

This paper reports on the spectral analysis of Eu3+ or Tb3+ ions (0.5mol%) doped heavy metal oxide (HMO) based zinc lead borate glasses from the measurement of their absorption, emission spectra and also different physical properties. From the XRD, DSC profiles, the glass nature and glass thermal properties have been studied. The measured emission spectrum of Eu3+ glass has revealed

A. Thulasiramudu; S. Buddhudu

2007-01-01

8

NIR Luminescence From Nd3+ And Er3+ Ions Doped Cadmium Borate Glasses For Optical Amplification  

NASA Astrophysics Data System (ADS)

In this paper, we report the near-infrared luminescence from the Nd3+ and Er3+ ions doped cadmium borate glasses for optical amplification. The absorption and luminescence spectra of the host glass matrix have been carried out at room temperature. From these spectra, Judd-Ofelt intensity and laser parameters have been computed and discussed. The NIR spectra of Nd3+ and Er3+ ions doped glasses have shown full-width at half maxim (FWHW) around 19, 21, 22 and 24 nm respectively. These glasses have potential applications in broadly tunable laser sources and broadband optical amplification at low-loss telecommunication windows.

Sharm, Y. K.; Joshi, R. P.; Surana, S. S. L.

2011-12-01

9

Fluorescence properties of Eu3+ ions doped borate and fluoroborate glasses containing lithium, zinc and lead.  

PubMed

The influence of glass composition on the fluorescence properties of Eu3+ ions doped borate and fluoroborate glasses modified with Li+, Zn2+ and Pb2+ cations have been investigated. The magnitude of splittings of 7F1 levels are analyzed using crystal-field (CF) analysis. The relative intensities of 5D0 --> 7F2 to 5D0 --> 7F1 transitions, crystal-field strength parameters and decay times of the 5D0 level have been determined and are found to be lower for Pb based glasses than those of Zn/Li based glasses. The lifetimes of 5D0 level are found to increase when borate glasses are modified with pure fluorides than with oxides and oxyfluorides. The fluorescence decay of 5D0 level fits perfect single exponential in the Eu3+:glass systems studied which indicates the absence of energy transfer between Eu3+ ions in these glasses. PMID:15979397

Venkatramu, V; Babu, P; Jayasankar, C K

2005-06-23

10

Physical and optical characterization of Er3+ doped lead-zinc-borate glass.  

PubMed

This paper reports on the systematic optical characterization of Er3+ (1.0%) doped lead-zinc-borate glass from the measured absorption, luminescence and fluorescence lifetime decay curve profiles. By the application of the Judd-Ofelt theory, spectral intensities of the absorption bands have been analysed and these absorption results have been used in evaluating the luminescence properties of the Er3+ doped lead-zinc-borate glass. Stimulated emission cross-sections (sigmapE) of the measured emission transitions have been computed. Based on the measured glass density, and refractive indices, other related physical parameters have also been evaluated. Further, the structural and morphology of the glass material have also been investigated from X-ray diffraction, Fourier transform infrared spectroscopy, and scanning electron microscopy analysis. PMID:19504881

Sooraj Hussain, N; Cardoso, P J; Hungerford, G; Gomes, M J M; Ali, Nasar; Santos, J D; Buddhudu, S

2009-06-01

11

Optical Properties of Eu3+ Doped Lead Borate Tellurite and Zinc Borate Tellurite Glasses  

NASA Astrophysics Data System (ADS)

This paper describes the synthesis and optical absorption studies of the glass system 20PbO-20TeO2-(60-x)B2O3-x Eu2O3 (x = 0,1 mol %) and 20ZnO-20TeO2-(60-x)B2O3-xEu2O3 (x = 0,1 mol %). These glass systems have been successfully prepared by the melt quenching technique. The X-ray diffractograms show broad peaks indicating glasses are amorphous. DSC thermograms show glass transition temperatures around 655K for PbO content and around 675 K for ZnO content glass samples. In the UV-Visible spectra, several absorption lines are observed. The absorption peaks are around 362, 375, 393 and 464 nm for both Eu3+ doped PbO and ZnO content glass systems. These correspond to transitions from ground state of 7F0 to the excited state of 5D4, 5G4, 5L6 and 5D2 respectively for both Eu3+ doped PbO and ZnO content glass systems. These glasses are expected to give interesting applications in the area of optical devices.

Shigihalli, N. B.; Rajaramakrishna, R.; Anavekar, R. V.

2011-07-01

12

Optical absorption and photoluminescence properties of Er3+ doped mixed alkali borate glasses.  

PubMed

An investigations of the optical absorption and fluorescence spectra of 0.2 mol% Er2O3 in mixed alkali borate glasses of the type 67.8B2O3 x xLi2O(32-x)Na2O, 67.8B2O3 x xLi2O(32-x)K2O and 67.8B2O3 x xNa2O(32-x)K2O (where x = 8, 12, 16, 20 and 24) are presented. The glasses were obtained by quenching melts consisting of H3BO3, Li2CO3, Na2CO3, K2CO3 and Er2O3 (950-1100 degrees C, 1.5-2 h) between two brass plates. Spectroscopic parameters like Racah (E1, E2 and E3), spin-orbit (xi(4f)) and configuration interaction (alpha) parameters are deduced as function of x. Using Judd-Ofelt theory, Judd-Ofelt intensity parameters (omega2, omega4 and omega6) are obtained. Radiative and non-radiative transition rates (A(T) and W(MPR)), radiative lifetimes (tauR), branching ratios (beta) and integrated absorption cross-sections (sigma) have been computed for certain excited states of Er3+ in these mixed alkali borate glasses. Emission spectra have been studied for all the three Er3+ doped mixed alkali borate glasses. The present paper throws light on the trends observed in the intensity parameters, radiative lifetimes, branching ratios and emission cross-sections as a function of x in these borate glasses, keeping in view the effect of mixed alkalies in borate glasses. PMID:15911407

Ratnakaram, Y C; Kumar, A Vijaya; Naidu, D Tirupathi; Rao, J L

2005-07-01

13

Up-conversion process in erbium doped lithium fluoride bulk crystal, lithium borate glass and glass ceramics  

NASA Astrophysics Data System (ADS)

In our research the up-conversion processes in Er doped bulk LiF crystal, lithium borate oxyfluoride glass and lithium borate oxyfluoride glass ceramics were studied: up-conversion and traditional photoluminescence spectra, the up-converted signal as a function of the laser power are presented. It was found that sharp luminescence bands in the visible part of the spectrum appear when the bulk crystal is subjected to IR irradiation at 980 nm by a laser diode. After the heat treatment of the glass submicron crystallites were detected by SEM technique. The presence of LiF crystalline phase in the oxyfluoride glass ceramics was proved by XRD method. The questions about the synthesis of the oxyfluoride glass ceramics and the possible mechanisms of the up-conversion process in the mentioned hosts are discussed.

Sarakovskis, A.; Dimitrocenko, L.; Misnevs, A.; Rogulis, U.; Springis, M.

2007-12-01

14

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.

15

Optical characterization of some rare earth ions doped bismuth borate glasses and effect of gamma irradiation  

NASA Astrophysics Data System (ADS)

Rare earth doped bismuth borate glasses were prepared by conventional melt annealing method. The density, molar volume, ultraviolet, visible, and infrared spectroscopic and optical energy band gap of these glasses have been measured or calculated and employed to investigate the prepared glassy samples. The refractive index and molar refraction have been calculated using the theory of reflectively of light. The luminescence properties of the glasses were analyzed. The undoped glass shows 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. The rare earth doped samples show the same strong UV-near visible bands as the undoped sample beside extra characteristic bands due to the respective rare earth ions. Results showed that the luminescence intensity changed with different rare earth oxides. 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. The IR spectra are slightly affected by gamma irradiation indicating the stability of the structural glassy forming units. The prepared samples reveal varying responses towards the effect of gamma irradiation.

Marzouk, M. A.

2012-07-01

16

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

NASA Astrophysics Data System (ADS)

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

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

2011-07-01

17

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

2010-04-28

18

Structural, dielectric and AC conductivity properties of Co2+ doped mixed alkali zinc borate glasses  

NASA Astrophysics Data System (ADS)

The Co2+ doped 19.9ZnO+5Li2CO3+25Na2CO3+50B2O3 (ZLNB) mixed alkali zinc borate glasses have been prepared by a conventional melt quenching method. The structural (XRD & FT-IR), dielectric and a.c. conductivity (?ac) properties have been investigated. Amorphous nature of these glasses has been confirmed from their XRD pattern. The dielectric properties and electrical conductivity (?ac) of these glasses have been studied from 100Hz to 5MHz at the room temperature. Based on the observed trends in the a.c. conductivities, the present glass samples are found to exhibit a non-Debye behavior.

Madhu, B. J.; Banu, Syed Asma; Harshitha, G. A.; Shilpa, T. M.; Shruthi, B.

2013-02-01

19

Optical absorption and photoluminescence properties of Dy3+ doped heavy metal borate glasses - Effect of modifier oxides  

NASA Astrophysics Data System (ADS)

The effect of modifier oxides on J-O intensity parameters and radiative properties are studied.Decay curves of 4F9/2 state exhibits non-exponential nature in all the glasses.Dy3+ doped different modifiers in zinc borate glasses exhibits white light emission under 450 nm excitation.

Sasi kumar, M. V.; Rajesh, D.; Balakrishna, A.; Ratnakaram, Y. C.

2013-06-01

20

Absorption and emission properties of Ho 3+ doped lead–zinc–borate glasses  

Microsoft Academic Search

This paper reports on the affect of lead content on the absorption and emission spectra of the Ho3+ ion doped lead–zinc–borate glasses in the composition (mol%) of (20?x)PbO–20ZnO–(59+x)B2O3–1.0Ho2O3 where x=0, 5,10,15 of PbO content with ?exc=405 nm. The experimental absorption band energies have satisfactorily been correlated with the theoretical results with an r.m.s deviation of zero with the following correction

N. Sooraj Hussain; N. Ali; A. G. Dias; M. A. Lopes; J. D. Santos; S. Buddhudu

2006-01-01

21

Optical Properties of Alkaline Earth Ions Doped Bismuth Borate Glasses  

SciTech Connect

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

Kundu, Virender [Department of Electronic Science, Kurukshetra University, Kurukshetra 136 119 (India); Dhiman, R. L. [Post-Graduate Department of Applied Physics, S.D. College, Ambala Cantt. 133 001 (India); Maan, A. S.; Goyal, D. R. [Department of Physics, Maharshi Dayanand University, Rohtak 124 001 (India)

2011-07-15

22

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

23

Optical characterization of Cu 2+ ion-doped zinc lead borate glasses  

Microsoft Academic Search

We have developed a new series of zinc lead borate (ZLB) glasses by varying ZnO content, to enhance UV transmission, in the chemical composition of xZnO–15PbO–(85?x)B2O3, where x=0, 5, 10, 15, 20, 25, 30, 35, 40 and 45mol% ZnO. From the measurement of UV absorption spectra both the direct and indirect band gaps have been evaluated. Also different physical properties

A. Thulasiramudu; S. Buddhudu

2006-01-01

24

Spectroscopic studies of lead antimony borate glasses doped with erbium ions  

NASA Astrophysics Data System (ADS)

Antimony borate glasses of the composition 30PbO-25Sb2O3-(45-x)B2O3-xEr2O3 with x = 0 to 1.0 in steps of 0.2 were prepared by the melt-quenching method. Various physical parameters. radiative parameters, transition probability A, branching ratio ? and the radiative life time ? for different emission levels of Er3+ ions, have been evaluated.

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

2013-06-01

25

The structural, optical and magnetic parameter of manganese doped strontium zinc borate glasses  

NASA Astrophysics Data System (ADS)

Glasses with composition 10SrO:(30-x)ZnO:60B2O3:xMnO, 0?x?0.9 (all compositions in wt%) have been prepared and investigated by X-ray diffraction, EPR, Optical absorption and FT-IR spectroscopic techniques. The XRD pattern of all the glasses confirmed the formation of an amorphous structure. The EPR spectra of all glass samples exhibit resonance signals at g?2.0 with a sextet of hyperfine lines. The spin concentration (N) and temperature dependence of EPR signals were studied for Mn2+ ions in strontium zinc borate glass samples. The zero-field splitting parameter D has been evaluated from the intensities of the allowed hyperfine lines. The paramagnetic susceptibility (?) was calculated from EPR data at different temperatures and the Curie temperature (?p) was calculated from the 1/? verses T graph. The optical absorption spectra exhibit a single broad band near 470 nm and this has been attributed to the spin-allowed 5Eg?5T2g transition of Mn3+ ions in octahedral symmetry. The theoretical optical basicity (?th) of these glasses have also been evaluated. The FTIR studies show BO3 and BO4 structural units in strontium zinc borate glasses.

Sumalatha, B.; Omkaram, I.; Rajavardhana Rao, T.; Linga Raju, Ch.

2013-02-01

26

Precipitation of ZnO in Al2O3-doped zinc borate glass ceramics  

NASA Astrophysics Data System (ADS)

Crystallization behavior of the oxide semiconductor ZnO in zinc borate glass was investigated. The precipitated crystalline phase of glass ceramics containing a small amount of Al2O3 was ?-Zn3B2O6 whereas that of the glass ceramics containing a large amount of Al2O3 was ZnO. It was found that the c-oriented precipitation of ZnO in a glass ceramic was brought about by the in-plane crystal growth of needle-like ZnO crystallites along the a-axis. Amount of Al2O3 that can make glass network affected the coordination state of B2O3 in the glass, and a three-coordinated BO3 unit was preferentially formed in the glass containing a higher amount of Al2O3. The present results suggest that crystallization of ZnO from multi-component glass is dominated by the local coordination state of the mother glass.

Masai, Hirokazu; Ueno, Takahiro; Takahashi, Yoshihiro; Fujiwara, Takumi

2011-10-01

27

Photon Interaction Parameters for Some Borate Glasses  

NASA Astrophysics Data System (ADS)

Some photon interaction parameters of dosimetric interest such as mass attenuation coefficients, effective atomic number, electron density and KERMA relative to air have been computed in the wide energy range from 1 keV to 100 GeV for some borate glasses viz. barium-lead borate, bismuth-borate, calcium-strontium borate, lead borate and zinc-borate glass. It has been observed that lead borate glass and barium-lead borate glass have maximum values of mass attenuation coefficient, effective atomic number and KERMA relative to air. Hence, these borate glasses are suitable as gamma ray shielding material, packing of radioactive sources etc.

Mann, Nisha; Kaur, Updesh; Singh, Tejbir; Sharma, J. K.; Singh, Parjit S.

2010-11-01

28

Photon Interaction Parameters for Some Borate Glasses  

SciTech Connect

Some photon interaction parameters of dosimetric interest such as mass attenuation coefficients, effective atomic number, electron density and KERMA relative to air have been computed in the wide energy range from 1 keV to 100 GeV for some borate glasses viz. barium-lead borate, bismuth-borate, calcium-strontium borate, lead borate and zinc-borate glass. It has been observed that lead borate glass and barium-lead borate glass have maximum values of mass attenuation coefficient, effective atomic number and KERMA relative to air. Hence, these borate glasses are suitable as gamma ray shielding material, packing of radioactive sources etc.

Mann, Nisha [Department of Applied Sciences, Samalkha Group of Institutions, Samalkha-132 101, Haryana (India); Kaur, Updesh; Singh, Tejbir; Sharma, J. K. [Department of Physics, Maharishi Markandeshwar University, Mullana-133 207, Haryana (India); Singh, Parjit S. [Department of Physics, Punjabi University, Patiala-147 002, Punjab (India)

2010-11-06

29

Er3+-doped strontium lithium bismuth borate glasses for broadband 1.5 ?m emission - optical properties  

NASA Astrophysics Data System (ADS)

Strontium lithium bismuth borate glasses (SLBiB) doped with various concentrations of Er3+ 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 Er3+ ions to evaluate J-O intensity parameters, ?? (? = 2, 4 and 6). Using the J-O intensity parameters, radiative properties such as transition probabilities (AR), branching ratios (?) and radiative lifetimes (?) are estimated for certain transitions. From the emission spectra, peak emission-cross sections (?p) and products of stimulated emission cross-section and full width at half maximum (?p×FWHM) were calculated for the observed emission transition, 4I13/2-->4I15/2.

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

2013-02-01

30

Electron paramagnetic resonance of vanadyl doped mixed alkaline earth borate glasses  

NASA Astrophysics Data System (ADS)

The ``mixed alkaline effect'' is one of the classical anomalies of glass science. We report here an interesting phenomenon ``Mixed Alkaline earth oxide Effect'' observed in a series of VO2+ ions doped in xMgO-(30-x)BaO-68B2O3-2V2O5 glass system. Glasses are investigated by EPR technique at X-band frequencies. The EPR spectra of all the glasses exhibited resonance signals characteristic of VO2+ ions in octahedral coordination with tetragonal compression and have C4V symmetry with ground state dxy. Tetragonality (?gll/?g?) of V4+ ion sites exhibited non-linear variation with MgO content, which indicated change in the ligand field at the site of V4+.

Samdani; Chandrasekhar, K.; Shareefuddin, Md.; Chary, M. Narasimha

2013-06-01

31

The spectroscopic properties of Er3+-doped antimony-borate glasses  

Microsoft Academic Search

The spectroscopic properties of Er3+-doped Sb2O3-B2O3 glass have been investigated for developing 1.55-mum broadband fiber amplifiers and tunable lasers. A broad 1.55-mum near infrared emission peaked at 1527 nm with a full width at half maximum (FWHM) of 91 nm has been obtained for 30Sb2O3-69B2O3-1Er2O2 glass upon excitation of a 980 nm laser diode. This broad luminescence locates in the

Q. Qian; Q. Y. Zhang; H. F. Jiang; Z. M. Yang; Z. H. Jiang

2010-01-01

32

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

SciTech Connect

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

Namma, Haydar Aboud; Wagiran, H.; Hussin, R.; Ariwahjoedi, B. [Department of Physics, Universiti Teknologi Malaysia, Skudai 81310, Malaysia and Baghdad College of Economic Sciences University (Iraq); Fundamental and Applied Sciences Department, Universiti Teknologi PETRONAS, 31750 Tronoh (Malaysia)

2012-09-26

33

Effect of Bi 2O 3 on spectroscopic and structural properties of Er 3+ doped cadmium bismuth borate glasses  

NASA Astrophysics Data System (ADS)

Glasses with composition 20CdO· xBi 2O 3·(79.5 - x)B 2O 3 (15 ? x ? 35, x in mol%) containing 0.5 mol% of Er 3+ ions were prepared by melt-quench technique (1150 °C in air). The amorphous nature of the glasses was confirmed by X-ray diffraction. The spectroscopic properties of the glasses were investigated using optical absorption spectra and fluorescence spectra. The phenomenological Judd-Ofelt intensity parameters ?? ( ? = 2, 4, 6) were determined from the spectral intensities of absorption bands in order to calculate the radiative transition probability ( AR), radiative life time ( ?R), branching ratios ( ?R) for various excited luminescent states. Using the near infrared emission spectra, full width at half maxima (FWHM), stimulated emission cross-section ( ?e) and figure of merit (FOM) were evaluated and compared with other hosts. Especially, the numerical values of these parameters indicate that the emission transition 4I 13/2 ? 4I 15/2 at 1.506 ?m in Er 3+-doped cadmium bismuth borate glasses may be useful in optical communication.

Sanghi, S.; Pal, I.; Agarwal, A.; Aggarwal, M. P.

2011-12-01

34

Effect of Bi2O3 on spectroscopic and structural properties of Er3+ doped cadmium bismuth borate glasses.  

PubMed

Glasses with composition 20CdO·xBi(2)O(3)·(79.5-x)B(2)O(3) (15?x?35, x in mol%) containing 0.5 mol% of Er(3+) ions were prepared by melt-quench technique (1150°C in air). The amorphous nature of the glasses was confirmed by X-ray diffraction. The spectroscopic properties of the glasses were investigated using optical absorption spectra and fluorescence spectra. The phenomenological Judd-Ofelt intensity parameters ?(?) (?=2, 4, 6) were determined from the spectral intensities of absorption bands in order to calculate the radiative transition probability (A(R)), radiative life time (?(R)), branching ratios (?(R)) for various excited luminescent states. Using the near infrared emission spectra, full width at half maxima (FWHM), stimulated emission cross-section (?(e)) and figure of merit (FOM) were evaluated and compared with other hosts. Especially, the numerical values of these parameters indicate that the emission transition (4)I(13/2)?(4)I(15/2) at 1.506 ?m in Er(3+)-doped cadmium bismuth borate glasses may be useful in optical communication. PMID:21890402

Sanghi, S; Pal, I; Agarwal, A; Aggarwal, M P

2011-08-06

35

Formation and evolution of magnetic nanoparticles in borate glass simultaneously doped with Fe and Mn oxides  

Microsoft Academic Search

Evolution of the phase state of paramagnetic additions at various stages of synthesis and subsequent thermal treatment of glasses of the system Al2O3-K2O-B2O3 simultaneously doped with Fe2O3 and MnO is studied by means of a combination of experimental techniques: Faraday rotation (FR), electron magnetic resonance (EMR), transmission electron microscopy (TEM), Mössbauer spectroscopy, and magnetic measurements. Both FR and EMR show

J. Kliava; I. Edelman; O. Ivanova; R. Ivantsov; O. Bayukov; E. Petrakovskaja; V. Zaikovskiy; I. Bruckental; Y. Yeshurun; S. Stepanov

2008-01-01

36

The spectroscopic properties of Er3+-doped antimony-borate glasses  

NASA Astrophysics Data System (ADS)

The spectroscopic properties of Er3+-doped Sb2O3-B2O3 glass have been investigated for developing 1.55-?m broadband fiber amplifiers and tunable lasers. A broad 1.55-?m near infrared emission peaked at 1527 nm with a full width at half maximum (FWHM) of 91 nm has been obtained for 30Sb2O3-69B2O3-1Er2O2 glass upon excitation of a 980 nm laser diode. This broad luminescence locates in the region of 1440-1650 nm and covers the S, C and L bands. The emission cross-section of the 4I13/2?4I15/2 transition of Er3+ ions and the measured lifetime of the 4I13/2 level of Er3+ ions are 6.01×10-21 cm2 and 0.341 ms, respectively. Based on the electronic polarizability of the oxide ion and optical basicity estimated from the values of refractive index and molar volumes, the covalent bonding character in the local ligand environments around Er3+ in Sb2O3-B2O3 glasses increases with increasing Sb2O3 content. It is noted that the product of the emission cross-section and the FWHM of the glass, ?e×FWHM, is as great as 567×10-28 cm3, which is comparable or higher than that of Er3+-doped tellurite- and germanate-based glasses.

Qian, Q.; Zhang, Q. Y.; Jiang, H. F.; Yang, Z. M.; Jiang, Z. H.

2010-05-01

37

Thermal and optical properties of Nd3+ doped lead zinc borate glasses—Influence of alkali metal ions  

NASA Astrophysics Data System (ADS)

In the present investigation a new series of six different Nd3+ doped alkali and mixed alkali (Li, Na, K, Li-Na, Li-K and Na-K) heavy metal (PbO and ZnO) borate glasses were prepared using the melt quenching technique. The amorphous nature of the glass systems has been identified based on the X-ray diffraction analysis. The glass transition studies were carried out using differential scanning calorimetry (DSC). Optical properties were studied by measuring the optical absorption and near infrared luminescence spectra. The Judd-Ofelt (J-O) theory has been applied to calculate J-O intensity parameters, ?? (?=2, 4 and 6) and in turn used to estimate radiative properties of certain transitions. Spectroscopic parameters such as transition probabilities (AT), branching ratios (?), radiative lifetimes (?R) and integrated absorption cross-sections (?) were calculated using J-O intensity parameters for all transitions. Using emission spectra, experimental branching ratios and stimulated emission cross-sections (?P) are obtained for all the observed emission transitions.

Sasi Kumar, M. V.; Rajesh, D.; Balakrishna, A.; Ratnakaram, Y. C.

2013-04-01

38

Judd–Ofelt parameters and radiative properties of Sm 3+ ions doped zinc bismuth borate glasses  

Microsoft Academic Search

Glasses having composition 20ZnO·xBi2O3·(79?x)B2O3 (15?x?35mol%) and doped with 1mol% Sm3+ ions have been prepared by melt quench technique. Optical absorption and fluorescence spectra have been recorded. Judd–Ofelt approach has been applied for the f?f transition of Sm3+ ions to evaluate various intensity parameters (?2,?4,?6). The variations in intensity parameters, radiative transition probabilities and hypersensitive band positions with composition have been

A. Agarwal; I. Pal; S. Sanghi; M. P. Aggarwal

2009-01-01

39

Absorption and luminescence spectroscopy of zinc borate glasses doped with trivalent lanthanide ions  

NASA Astrophysics Data System (ADS)

Absorption and luminescence spectra and decay curves have been measured at temperatures down to 12 K for 4ZnO-3B2O3 glasses doped with Pr3+ and Eu3+. Analysis of the spectra has yielded information about the probability of the radiative transitions in the impurity ions and the strength of the electron-phonon coupling. The strongly non-exponential decay curves indicate the importance of energy transfer and migration processes accounting for the dynamics of the excited states of Pr3+.

Ambrosi, Luigi; Bettinelli, Marco; Cormierand, Guy; Ferrari, Maurizio

40

Optical and other spectroscopic studies of lead, zinc bismuth borate glasses doped with CuO  

NASA Astrophysics Data System (ADS)

10MO·20Bi2O3·(70-x)B2O3·xCuO [M=Pb, Zn] with x=0, 0.4 and 0.8 (wt%) glasses were synthesized by the melt-quenching technique and were characterized using X-ray diffraction (XRD) and scanning electron microscopy (SEM) techniques. Physical parameters, like density, and spectroscopic studies (optical absorption, EPR, FTIR and photoluminescence) were used to understand the role of modifier oxide and CuO in the glass matrix. A red shift of the absorption band corresponds to 2B1g?2B2g transition of Cu2+ ions from P2 to Z4 samples and the increase of hyperfine splitting factor (A?) from P2 to Z2 shows that with the integration of PbO by ZnO the electron density around copper ion is increased. It is also supported by the gradual increase in theoretical optical basicity values of ZnO mixed glasses, as compared to that of PbO mixed glass matrix. Reduced bismuth radicals are found in undoped and 0.4% CuO doped glasses of both the series. Analysis of the absorption and emission studies indicates that the concentration of luminescence centers of bismuth ions (Bi3+ ions in UV region) is decreased by the integration of ZnO as well as by increasing the dopant concentration. In lead series PbO4 and BiO3 units are increased from P2 to P4 and in zinc series BiO3 units are decreased from Z0 to Z4. The conductivity of the glass matrices is increased in both the series with the dopant of CuO.

Rajyasree, Ch.; Vinaya Teja, P. Michael; Murthy, K. V. R.; Krishna Rao, D.

2011-12-01

41

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

2008-12-11

42

Alkaline earth zinc borate glasses doped with Cu 2+ ions studied by EPR, optical and IR techniques  

Microsoft Academic Search

Copper ions incorporated into alkaline earth zinc borate glasses 10RO+30ZnO+60B2O3 (R=Mg, Ca and Sr) and 10SrO+(30?x)ZnO+60B2O3+xCuO (x=0, 0.1, 0.3, 0.5, and 0.7wt.%) were characterized by electron paramagnetic resonance (EPR), optical absorption and FTIR techniques. The EPR spectra of all the glass samples exhibit resonance signals characteristic of Cu2+ ions. The values of spin-Hamiltonian parameters indicate that the Cu2+ ions in

B. Sumalatha; I. Omkaram; T. Rajavardhana Rao; Ch. Linga Raju

2011-01-01

43

Optical characterization of Mn 2+, Ni 2+ and Co 2+ ions doped zinc lead borate glasses  

Microsoft Academic Search

This paper reports on the development and optical characterization of heavy metal oxide (HMO)-based transparent glasses in the chemical composition of 15PbO–40B2O3–(45?x) ZnO?x TM2+ (=Mn2+ or Ni2+ or Co2+) (where x=0.2, 0.5mol%). For these glasses both absorption and emission spectra have been measured, in order to understand their optical performances. The XRD profiles have confirmed their glassy nature and the

A. Thulasiramudu; S. Buddhudu

2006-01-01

44

Structural and physical properties of vanadium doped copper bismuth borate glasses  

NASA Astrophysics Data System (ADS)

The structural and physical properties of xCuO(30-x)Bi2O3-70B2O3 x = 0, 5, 10, 15, 20 & 25 mol % with 2 mol % V2O5 glasses prepared by normal melt quench technique have been investigated by means of FT-IR & 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 BO3 to BO4 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 BiO3 pyramidal, BiO6 octahedral units and also on BO3 and BO4 structural units. The systematic variation in density and molar volume in these glasses indicates the effect of CuO substitution.

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

2013-02-01

45

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

46

Physical, Absorption and Fluorescence Spectral Studies of Pr3+ Ions Doped Lithium Bismuth Borate Glasses  

NASA Astrophysics Data System (ADS)

Glasses of the system: xB2O3-10Bi2O3-30Li2O-xPr6O11 where x =1, 1.5 and 2 were prepared by melt quenching technique. Optical absorption and emission spectra have been recorded. The intensities of f-f transition are calculated in term of Judd-Ofelt (JO) intensity parameters ?? (? = 2, 4 and 6). Using the fluorescence data and these ?? parameters, various radiative properties like transition probability (Arad), branching ratio (?R), radiative lifetime (?R), and stimulated emission cross section (?p), of various emission lines have been evaluated. The branching ratio for 3P0?3H4 transition is 56% and the predicted spontaneous radiative transition probability rates are fairly high 16411 s?1. This is beneficial for lasing emission.

Bhatia, Beena; Parihar, Vishal

47

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

SciTech Connect

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

Chanturiya, G F; Kutaladze, L M; Tatarashvili, R A [Institute of Cybernetics of the Academy of Sciences of Georgia, Tbilisi (Georgia); Shchegolikhin, Aleksandr N [Institute for Biochemical Physics, Russian Academy of Sciences, Moscow (Russian Federation)

2004-04-30

48

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

Microsoft Academic Search

Glass samples of manganese oxide borate and zinc oxide borate (with and without ferric oxide doping) have been prepared to study their acoustical, mechanical, and thermal behavior as function of composition. Sound velocities and attenuation measurements in these glass systems at 1,2, and 5 MHz give elastic moduli, Poissons ratio, micro-hardness, acoustic impedance, internal friction, thermal expansion coefficient and Debye

Surjit Singh Bhatti; Kanwar Jit Singh

2003-01-01

49

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

50

Effect of Li2O content on physical and structural properties of vanadyl doped alkali zinc borate glasses  

NASA Astrophysics Data System (ADS)

The effect of Li2O content in vanadyl doped 20ZnO+xLi2O+(30-x)Na2O+50B2O3 (5?x?25) glasses has been studied with respect to their physical and structural properties. The absence of sharp peaks in XRD spectra of these glass samples confirms the amorphous nature. The physical parameters like density, refractive index, ionic concentration and electronic polarizability vary non-linearly with x mol% depending on the diffusivities of alkali ions. EPR and optical absorption spectra reveal that the resonance signals are characteristics of VO2+ ions in tetragonally compressed octahedral site. Spin-Hamiltonian, crystal field, tetragonal field and bonding parameters are found to be in good agreement with the other reported glass systems. The tetragonal distortion (g?-g?) and Dt reveals that their values vary non-linearly with Li2O content and reaches a minimum at x=10 mol%. An anomaly of character has been observed in all the properties of vanadyl doped glass systems, which gives a clear indication of mixed alkali effect.

Raghavendra Rao, T.; Rama Krishna, Ch.; Udayachandran Thampy, U. S.; Venkata Reddy, Ch.; Reddy, Y. P.; Sambasiva Rao, P.; Ravikumar, R. V. S. S. N.

2011-05-01

51

Bioactive borate glass coatings for titanium alloys.  

PubMed

Bioactive borate glass coatings have been developed for titanium and titanium alloys. Glasses from the Na(2)O-CaO-B(2)O(3) system, modified by additions of SiO(2), Al(2)O(3), and P(2)O(5), were characterized and compositions with thermal expansion matches to titanium were identified. Infrared and X-ray diffraction analyses indicate that a hydroxyapatite surface layer forms on the borate glasses after exposure to a simulated body fluid for 2 weeks at 37 degrees C; similar layers form on 45S5 Bioglass((R)) exposed to the same conditions. Assays with MC3T3-E1 pre-osteoblastic cells show the borate glasses exhibit in vitro biocompatibility similar to that of the 45S5 Bioglass((R)). An enameling technique was developed to form adherent borate glass coatings on Ti6Al4V alloy, with adhesive strengths of 36 +/- 2 MPa on polished substrates. The results show these new borate glasses to be promising candidates for forming bioactive coatings on titanium substrates. PMID:18415004

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

2008-04-15

52

Nanocomposites Based on Immiscible Borate Glasses  

Microsoft Academic Search

Synthesis of immiscible borate glasses containing PbO, TeO2 and Fe2O3 was performed by conventional melting technology and by lowtemperature sol-gel method. Thermal treatment was performed to\\u000a obtain glasscrystalline materials. Incorporation techniques were used for the preparation of nanostructured composites based\\u000a on an amorphous matrix and crystalline powder nanoparticles of PbMoO4 and Fe3O4. Structural characterisation of nanoparticles and nanocomposites was performed

Vanya Ivanova; Elena Kashchieva; Yanko Dimitriev

53

Structure and conductivity of fast ion-conducting borate glasses  

NASA Astrophysics Data System (ADS)

We have performed neutron and X-ray diffraction experiments and made structural models using the reverse Monte-Carlo (RMC) simulation technique. In order to obtain insights into the relation between the structure and ionic conduction for the two fast ion-conducting glasses (AgI)0.6 (Ag2O-2B2O3)0.4 and LiCl-Li2O-2B2O3. Large differences between the two glass structures are observed on an intermediate (4-20 Å) length-scale. A first remarkably intense diffraction peak at the low momentum transfer of 0.8 Å-1 in S(Q) of the AgI-doped glass is found to be due to inter-chain correlations of about 8-10 Å within the boron-oxygen network. The salt ions cross-link between the borate chains and are therefore located in pathways suitable for ion conduction. The LiCl-doped glass, on the other hand, does not show any low-Q peak in S(Q) or any characteristic intermediate distance.

Swenson, J.; Börjesson, L.; McGreevy, R. L.; Howells, W. S.

1997-02-01

54

Nearly constant loss effects in borate glasses.  

PubMed

Different nearly constant loss phenomena are investigated in borate glasses with compositions xNa(2)O.(1-x)B(2)O(3), for 0 < or =x< or = 0.3. The ionic conductivities caused by these effects are studied in wide ranges of temperature and frequency, spanning 4.3 K to 573 K and 100 mHz to 1 MHz, respectively. In a first step, we show how to identify the nearly constant loss (NCL) in 0.3Na(2)O.0.7B(2)O(3) glass. In the procedure, the scaling property of the conductivity caused by ordinary hopping is used to remove this component from the total conductivity as measured as a function of temperature at fixed frequency. The resulting NCL component is seen to be proportional to frequency and to display no temperature dependence. In a second step, a broad-band relaxation process is shown to exist in amorphous boron oxide and in sodium borate glasses with x< or = 0.1. It is most probably due to the presence of traces of water, with hydrogen ions behaving as reorienting and interacting local dipoles. In a third step, we propose a simple formal treatment of the NCL phenomenon, tracing it back to a large number of interacting ions, each of them moving locally. The key aspect is a "see-saw-type" time dependence of their individual single-particle double-well potentials, which is due to their Coulomb interactions. The individual ion does, therefore, not require thermal activation and is thus kept in motion even at cryogenic temperatures. PMID:19370211

Laughman, David M; Banhatti, Radha D; Funke, Klaus

2009-03-10

55

The preparation and properties of some lithium borate based glasses  

Microsoft Academic Search

The preparation and properties of lithium borate based glasses are described. The properties which were monitored included the glass-forming ability, the thermal stability, the chemical durability and the mechanical behaviour. Methods which were used in an attempt to improve the mechanical properties of these glasses are also discussed, including controlled crystallization, chemical ion-exchange and fibre reinforcement. The strongest glass, which

I. W. Donald; B. L. Metcalfe; D. J. Bradley; M. J. C. Hill; J. L. McGrath; A. D. Bye

1994-01-01

56

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

NASA Astrophysics Data System (ADS)

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

Bhatti, Surjit Singh; Singh, Kanwar Jit

2003-04-01

57

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

SciTech Connect

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

Harihara Venkataraman, B. [Department of Materials Science and Technology, Nagaoka University of Technology, 1603-1 Kamitomioka-cho, Nagaoka 940-2188 (Japan); Fujiwara, Takumi [Department of Applied Physics, Graduate School of Engineering, Tohoku University, Sendai 980-8579 (Japan); Komatsu, Takayuki, E-mail: komatsu@mst.nagaokaut.ac.j [Department of Materials Science and Technology, Nagaoka University of Technology, 1603-1 Kamitomioka-cho, Nagaoka 940-2188 (Japan)

2009-06-15

58

Infrared absorption spectroscopy of zinc borate and vanadium borate glasses  

Microsoft Academic Search

As part of a general research programme on oxide glasses we have studied the infrared absorption spectra in order to ascertain whether any local ordering characteristic of the constituent oxides is maintained in the final glass. Zachariasen [1] assumed as a general rule that in the amorphous state, the oxides which form such glasses are in energy states not much

C. A. Hogarth; M. M. Ahmed

1983-01-01

59

Relationship between Eu3+ reduction and glass polymeric structure in Al2O3-modified borate glasses under air atmosphere  

NASA Astrophysics Data System (ADS)

The reduction of Eu3+ to Eu2+ is realized efficiently in Eu2O3-doped borate glasses prepared under air condition by melting-quenching method. Luminescent spectra show an increasing tendency of Eu2+ emission with increasing Al2O3 concentration in B2O3-Na2O glasses. It is interesting that significant enhancement appeared of Eu2+ luminescence in the Al2O3-rich sample comparing to the samples of Al2O3 less than 6 mol%. FTIR and Raman scattering measurements indicated that some new vibration modes assigned to the low-polymerized structure groups decomposed from the slight Al2O3 dopant samples. These results demonstrated that the polymerization of the glass structure decreased with increasing incorporation of Al2O3 into the borate glasses, linking to the efficiency of Eu3+ self-reduction in air at high temperature.

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

2013-06-01

60

NEUTRON SPECTROSCOPIC STUDIES OF CAESIUM BORATE CRYSTALS AND GLASSES  

Microsoft Academic Search

The properties of alkali borate glasses are determined by the extent and detail of any molecule- like short-range order which persists in the amorphous structures. Although there is considerable evidence that these structures can contain significant proportions of superstructural units, quantitative evidence is difficult to obtain experimentally. Spectroscopic data are invaluable for testing models of glass structure and the inelastic

Roger N. Sinclair; Richard Haworth; Adrian C. Wright; G. Parkinson; Diane Holland; Jon W. Taylor; Natalia M. Vedishcheva; Irina G. Polyakova; Boris A. Shakhmatkin; Steven A. Feller; B Rijal; T Edwards

61

Barium-borate-flyash glasses: As radiation shielding materials  

NASA Astrophysics Data System (ADS)

The attenuation coefficients of barium-borate-flyash glasses have been measured for ?-ray photon energies of 356, 662, 1173 and 1332 keV using narrow beam transmission geometry. The photon beam was highly collimated and overall scatter acceptance angle was less than 3°. Our results have an uncertainty of less than 3%. These coefficients were then used to obtain the values of mean free path (mfp), effective atomic number and electron density. Good agreements have been observed between experimental and theoretical values of these parameters. From the studies of the obtained results it is reported here that from the shielding point of view the barium-borate-flyash glasses are better shields to ?-radiations in comparison to the standard radiation shielding concretes and also to the ordinary barium-borate glasses.

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

2008-01-01

62

Strontium borate glass: potential biomaterial for bone regeneration  

PubMed Central

Boron plays important roles in many life processes including embryogenesis, bone growth and maintenance, immune function and psychomotor skills. Thus, the delivery of boron by the degradation of borate glass is of special interest in biomedical applications. However, the cytotoxicity of borate glass which arises with the rapid release of boron has to be carefully considered. In this study, it was found that the incorporation of strontium into borate glass can not only moderate the rapid release of boron, but also induce the adhesion of osteoblast-like cells, SaOS-2, thus significantly increasing the cyto-compatibility of borate glass. The formation of multilayers of apatite with porous structure indicates that complete degradation is optimistic, and the spread of SaOS-2 covered by apatite to form a sandwich structure may induce bone-like tissue formation at earlier stages. Therefore, such novel strontium-incorporated borosilicate may act as a new generation of biomaterial for bone regeneration, which not only renders boron as a nutritious element for bone health, but also delivers strontium to stimulate formation of new bones.

Pan, H. B.; Zhao, X. L.; Zhang, X.; Zhang, K. B.; Li, L. C.; Li, Z. Y.; Lam, W. M.; Lu, W. W.; Wang, D. P.; Huang, W. H.; Lin, K. L.; Chang, J.

2010-01-01

63

Fracture toughness and fracture surface energy of lead borate glasses  

Microsoft Academic Search

The structure of lead borate glasses has been investigated in detail by Bray and his co-workers using nuclear magnetic resonance (NMR) techniques [1,2]. They revealed that the fraction of four-co-ordinated boron atoms shows a maximum at about 50 tool % PbO and that the lead enters the glass as modifier Pb 2+ ions at lower PbO content but, with increasing

N. Miyata; H. Jinno

1982-01-01

64

Structure of fast-ion-conducting lithium and sodium borate glasses by neutron diffraction and reverse Monte Carlo simulations  

NASA Astrophysics Data System (ADS)

The structures of fast-ion-conducting glasses (NaZ)x(Na2O-2B2O3)1-x and (LiZ)x(Li2O-2B2O3)1-x (Z=Cl,Br) have been examined by neutron diffraction and reverse Monte Carlo (RMC) simulations. The short-range structure of the boron-oxygen network is almost unchanged for increasing dopant salt concentration and independent of the dopant salt, whereas the intermediate range order of the B-O network decreases significantly for increasing dopant salt concentration. The sodium borate glasses are generally slightly more ordered than the corresponding lithium borate glasses. The differences may be explained by the fact that the Li-borate glasses consist of a disordered random mixture of many different types of borate configurations, while the Na-borate glasses are built up by randomly distributed diborate groups, as suggested previously from NMR results. The RMC simulations of the highest LiCl- and NaCl-doped glasses show, however, that large density fluctuations are present within the boron-oxygen network. The voids are of widely different sizes and geometrical shapes. The present findings show that the intermediate-range order of the LiCl- and NaCl-doped glasses is significantly different from that recently reported for the corresponding AgI-doped glass. For the latter the boron-oxygen network forms a more ordered chainlike structure with the salt ions cross linking between the ``chains.''

Swenson, J.; Börjesson, L.; Howells, W. S.

1998-06-01

65

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

NASA Astrophysics Data System (ADS)

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 "doped" glasses by MIR spectroscopy. The modifying properties of the lithium oxide on the binary system B2O3-Li2O are investigated by the same technique and the results are used to understand the modifications of the boron-oxygen network induced by the "doping salt". The observed results depend on the type of salt anions: fluoride anions participate directly to the O/B network while chloride and bromide anions are in interstitial position in the glass matrix.

Massot, M.; Julien, C.; Balkanski, M.

1989-05-01

66

Cell adhesion to borate glasses by colloidal probe microscopy.  

PubMed

The adhesion of osteoblast-like cells to silicate and borate glasses was measured in cell growth medium using colloidal probe microscopy. The probes consisted of silicate and borate glass spheres, 25-50 ?m in diameter, attached to atomic force microscope cantilevers. Variables of the study included glass composition and time of contact of the cell to the glasses. Increasing the time of contact from 15 to 900 s increased the force of adhesion. The data could be plotted linearly on a log-log plot of adhesive force versus time. Of the seven glasses tested, five had slopes close to 0.5, suggesting a square root dependence of the adhesive force on the contact time. Such behavior can be interpreted as a diffusion limited process occurring during the early stages of cell attachment. We suggest that the rate limiting step in the adhesion process is the diffusion of integrins resident in the cell membrane to the area of cell attachment. Data presented in this paper support the hypothesis of Hench et al. that strong adhesion depends on the formation of a calcium phosphate reaction layer on the surfaces of the glass. Glasses that did not form a calcium phosphate layer exhibited a weaker adhesive force relative to those glasses that did form a calcium phosphate layer. PMID:21241832

Wiederhorn, Sheldon M; Chae, Young-Hun; Simon, Carl G; Cahn, Jackson; Deng, Yan; Day, Delbert

2011-01-15

67

Wavelength interdependence assessment of all-optical switching in zinc borate glasses  

NASA Astrophysics Data System (ADS)

Lithium tungsten borate photonic glass is prepared by the conventional melt-quench technique. Due to semiconductor-like behavior of zinc oxide, the glass is doped by ZnO to adapt its optical nonlinearity. Fresnel-based spectrophotometric measurements and Lorentz dispersion theory are applied to study (in a very wide range of photon energy from 0.5 to 6.2 eV) the dispersion of second-order refractive index, two-photon absorption coefficient, and third-order optical susceptibility of the glass. The figure of merit (FOM) needed for optical switching applications is estimated. We reveal the importance of determining the dispersion of the optical nonlinear parameters to find out the appropriate operating wavelength for optimum FOM of the glass.

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

2012-08-01

68

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

69

Photostimulated decay of radiation color centers in alkali borate glasses  

SciTech Connect

The decay of color centers in alkali borate glasses exposed to polarized optical radiation is studied. Optical irradiation of {gamma}-colored glasses is shown to destruct all types of color centers investigated. The mechanism of decay is defined by the type of color centers excited by a given type of radiation. Decay may be due either to photoionization of electron-type centers and subsequent recombination of the released electrons with hole-type centers or to delocalization of holes from hole-type centers and their subsequent recombination with electrons from electron-type centers.

Barinova, N.A.; Glebov, L.B. [Research and Technological Institute of Optical Materials Science, St. Petersburg (Russian Federation)

1994-05-01

70

Molecular dynamics study of the structure of borate glasses  

NASA Astrophysics Data System (ADS)

Boron plays an important role in numerous glasses. However, its role in glass structure is far from being completely understood. This may be due to the complexity of the boron-oxygen bond such as its partial convalency, p bond characteristics and easy structural conversion from BO3 triangle to BO4 tetrahedron. The borate glass systems, vitreous B2O3, alkali borate and borosilicate, are investigated by molecular dynamics (MD) computer simulations, adopting a coordination dependent potential scheme. The simulated vitreous B2O3 is comprised mainly of randomly connected BO3 triangles and some boroxol rings. The pair distribution functions and bond angle distributions are well matched to the experimental data. The fraction of boron atoms in boroxol rings in the simulated glass is 13--18%, which supports the interpretation of the reverse Monte Carlo and Monte Carlo calculations, but it is somewhat lower than that inferred from neutron diffraction results where values up to 80% are claimed. The simulated sodium borate and lithium borate glasses consist of not only BO3 and BO4 basic structural units, but also superstructural groupings such as boroxol rings, triborate and di-triborate units, etc. The addition of alkali converts BO3 triangles to BO4 tetrahedra and generates nonbridging oxygens at the same time. N4, the fraction of tetrahedrally coordinated boron, reaches a maximum at 40 mol% alkali oxide. Sodium and lithium metal ions are found near nonbridging oxygens and nonbridging oxygens are associated mainly with BO3 triangles rather than BO 4 tetrahedra. The boron anomaly seems to be related to a formation of nonbridging oxygen around 20--30 mol% of alkali metal oxide. The difference in behavior between lithium and sodium ions is explained using acidity/basicity concepts. To simulate alkali borosilicate glasses, a two-body potential for silicon-oxygen and three-body potentials for silicon-oxygen-silicon and oxygen-silicon-oxygen bond angles were developed for the oxygen-oxygen potential parameter used in the model of vitreous B2O3. Simulated pure (alkali-free) borosilicate glass consists of BO3 triangles and SiO4 tetrahedron. The structure of simulated sodium borosilicate glass depends on R and K, where R is the ratio of alkali oxide to boric oxide and K, that of silica to boric oxide.

Park, Byeongwon

71

Electronic spectroscopy of trivalent lanthanide ions in lead zinc borate glasses  

Microsoft Academic Search

New zinc borate glasses of composition 4PbO·2ZnO·5B2O3· and 2PbO·4ZnO·5B2O3 doped with Pr3+, Nd3+, Eu3+, Dy3+, Ho3+ and Er3+ were prepared. Absorption and luminescence spectra were measured and the Judd–Ofelt parameters were calculated. The spectroscopic behaviour appears to be strongly influenced by the presence of the highly polarizable Pb2+ ion. The values of stimulated emission cross sections for selected laser transition

Adolfo Speghini; Massimo Peruffo; Maurizio Casarin; David Ajò; Marco Bettinelli

2000-01-01

72

Reaction of sodium calcium borate glasses to form hydroxyapatite.  

PubMed

This study investigated the transformation of two sodium calcium borate glasses to hydroxyapatite (HA). The chemical reaction was between either 1CaO . 2Na(2)O . 6B(2)O(3) or 2CaO . 2Na(2)O . 6B(2)O(3) glass and a 0.25 M phosphate (K(2)HPO(4)) solution at 37, 75 and 200 degrees C. Glass samples in the form of irregular particles (125-180 microm) and microspheres (45-90 and 125-180 microm) were used in order to understand the reaction mechanism. The effect of glass composition (calcium content) on the weight loss rate and reaction temperature on crystal size, crystallinity and grain shape of the reaction products were studied. Carbonated HA was made by dissolving an appropriate amount of carbonate (K(2)CO(3)) in the 0.25 M phosphate solution. X-ray diffraction, Fourier transform infrared spectroscopy, and scanning electron microscopy were used to characterize the reaction products. The results show that sodium calcium borate glasses can be transformed to HA by reacting with a phosphate solution. It is essentially a process of dissolution of glass and precipitation of HA. The transformation begins from an amorphous state to calcium-deficient HA without changing the size and shape of the original glass sample. Glass with a lower calcium content (1CaO . 2Na(2)O . 6B(2)O(3)), or reacted at an elevated temperature (75 degrees C), has a higher reaction rate. The HA crystal size increases and grain shape changes from spheroidal to cylindrical as temperature increases from 37 to 200 degrees C. Increase in carbonate concentration can also decrease the crystal size and yield a more needle-like grain shape. PMID:17486301

Han, Xue; Day, Delbert E

2007-05-08

73

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

74

Preparation and properties of porous microspheres made from borate glass.  

PubMed

Dysprosium lithium-borate glass microspheres and particles, ranging from 45 to 150 microm in diameter, were reacted with a 0.25 M phosphate solution at 37 degrees C, whose pH was either 3 or 8.8. The glass reacted nonuniformly and was converted into a porous, amorphous, hydrated, dysprosium phosphate reaction product. The amorphous product had the same volume and shape (pseudomorphic) as the unreacted glass, and could be dried without cracking. After heating at 300 degrees C for 1 h, the amorphous reaction product had a specific surface area of approximately 200 m(2)/g, a pore size of approximately 30 nm, and nominal crushing strength of approximately 10 MPa. When the reaction product was heated to 600 degrees C for 15 min, the specific surface area decreased to approximately 90 m(2)/g and the nominal crushing strength increased to 35 MPa. Heating above 615 degrees C converted the amorphous dysprosium phosphate product into crystalline DyPO(4), which contained open porosity until heated above 800 degrees C for 15 min. Highly porous materials of different chemical composition can be prepared by chemically reacting a borate-based glass with an aqueous solution at low-temperature (<100 degrees C). These highly porous materials are easy to process, and are considered candidates for controlled drug delivery, catalysis, chromatographic separation, filtration, and as bioactive materials. PMID:18306308

Conzone, Samuel D; Day, Delbert E

2009-02-01

75

Structure and surface chemistry of borate and boroaluminate glasses  

NASA Astrophysics Data System (ADS)

The short and intermediate range structure of boroaluminate glasses has been investigated using solid state magic angle spinning nuclear magnetic resonance (MAS NMR). It was found that the aluminum ion may exhibit 4, 5, and 6-fold coordination. It was also shown that the aluminum can adopt the role of both a modifier and network former in the glass backbone. The dependence of the local aluminum structure on composition is discussed. The intermediate range order in barium boroaluminate glasses was directly probed using solid state double resonance NMR experiments. It was found that connections between (AlOsb{4/2})sp- and (BOsb{4/2})sp- units are strongly discouraged. This restriction affects the short range order of the boron atoms in the glass since it places a constraint on the maximum number of possible tetrahedral boron and aluminum-oxide polyhedra in the glass. The surface structure and chemistry in borate and boroaluminate glasses has been investigated. X-ray photoelectron spectroscopy (XPS), low energy ion scattering spectroscopy (ISS) and sp1H->sp{11}B cross polarization (CP) MAS NMR have been used in the surface characterization. O 1s and B 1s chemical shifts in the XPS spectra were described using a modified Sanderson model for the calculation of charge density. A peak corresponding to non-bridging oxygens (NBO) in the borate glasses was identified and used to quantify the NBO density. ISS analyses of the outermost atomic layer of clean vacuum fracture surfaces showed that relaxation of the surface atoms occurs during or shortly after the fracture event. The surface was found to be depleted in modifying cations, in contrast to silicate glasses. This is thought to be due to a conversion of tetrahedral units to trigonal coordination in an effort to reduce surface energy. Melt surfaces and graphite interfaces were found to exhibit chemical deviations from the corresponding fracture surfaces. The chemical shifts in the XPS spectra were consistent with enrichment of trigonally-coordinated boron-oxide units at the melt and interface surfaces. ISS and CP MAS NMR analyses of borate glass surfaces formed at high temperatures also provide direct evidence of structural rearrangement concordant with the geometrical optimization of the planar BOsb3 groups at the surface.

Beall, Douglas Munroe

76

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

77

Optical properties of lead borate glasses containing Dy3+ ions  

NASA Astrophysics Data System (ADS)

Optical properties of lead borate glasses containing Dy3+ ions were examined using absorption and luminescence measurements and theoretical calculations based on the Judd-Ofelt framework and the Inokuti-Hirayama model. The luminescence spectra show two characteristic bands at 480 and 573 nm, which are due to 4F9/2-6H15/2 (blue) and 4F9/2-6H13/2 (yellow) transitions of trivalent Dy3+ ions. The yellow/blue luminescence and its decay were analyzed as a function of activator concentration.

Pisarska, Joanna

2009-07-01

78

Ytterbium-doped borate fluoride laser crystals and lasers  

DOEpatents

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

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

1997-10-14

79

Ytterbium-doped borate fluoride laser crystals and lasers  

DOEpatents

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

Schaffers, Kathleen I. (Pleasanton, CA); DeLoach, Laura D. (Manteca, CA); Payne, Stephen A. (Castro Valley, CA); Keszler, Douglas A. (Corvallis, OK)

1997-01-01

80

Structure of borate glasses from neutron-diffraction experiments  

NASA Astrophysics Data System (ADS)

Systematic neutron-diffraction experiments have been performed on metal oxide modified borate glasses, xM2O-2B2O3 with M=Ag,Li,Na, in order to investigate the short- and intermediate-range structure. The short-range order of the boron-oxygen network, involving the first B-O, B-B, and O-O interatomic distances, is found to be almost identical for the silver, lithium, and sodium borates of the same modifier concentration. A detailed analysis of the first peak in the atomic pair correlation function reveals two different B-O nearest-neighbor distances, 1.37 and 1.47 Å, which are attributed to BO3 and BO4 groups, respectively. The relative abundance of three and four coordinated borons are determined for variations of the metal oxide content and found to be in accordance with reported nuclear magnetic resonance results. The low momentum transfer (Q) range of the structure factors of the various metal-oxide modified glasses are significantly different, which indicates differences in the structural organization on an intermediate length-scale 5-15 Å. For Ag2O and Na2O modifications considerably longer range correlations are observed as compared with pure vitreous B2O3. In contrast, in the case of Li2O modification no dramatic change of the intermediate-range order is observed. The different behavior is due to differences in the relative topological arrangements of the various borate groups formed, which in turn appears to be related to the size and degree of covalency of the cation and hence to its ability to form bridges between segments of the BO network.

Swenson, J.; Börjesson, L.; Howells, W. S.

1995-10-01

81

Optical study of Ce3+ ion in gamma-irradiated binary barium-borate glasses  

NASA Astrophysics Data System (ADS)

Absorption spectra measurements of cerium-doped binary system from barium-borate glasses have been measured. The effects of dopant concentration of CeO2 and Al2O3 in the concentration range 0.54 2.9 and 4.8 9.2 mol%, respectively, and exposed to different irradiation doses have been measured in the range 1 7 eV and the result have been interpreted in terms of structural concepts. The radiation-induced broad band at 2.25 1.88 eV in the base glass is observed to be suppressed by the presence of cerium due to the transformation of Ce4+ to Ce3+. The released electrons are then used to annihilate positive holes responsible for this band. The resolution of the observed absorption spectra show two to seven induced bands depending on the glass composition. Absorption spectra of the irradiated binary glass system are found to be controlled by the cerium concentration. From the absorption edge studies, the values of optical band gap Eopt and Urbach energy ?E have been evaluated. The oxidoreduction (redox) reaction Ce3+/Ce4+ is assumed to be related to the glass basicity and the possible complex-ion formation. The oxygen ion activity (O2-) is believed to be related to the basicity and to the possible oxygen ion formation in the glass melt, and the redox equilibrium is shifted toward the reduced state.

Marzouk, S. Y.; Ezz-Eldin, F. M.

2008-09-01

82

Stability of cement-glass packages containing sodium borate salt generated from pressurized water reactor power plants  

Microsoft Academic Search

A new solidification technique using cement-glass, which is a mixture of sodium silicate and cement, was studied for solidification of sodium borate salt of liquid waste generated from pressurized water reactor plants. When the sodium borate salt was solidified with the cement-glass, the resulting package contained eight times more sodium borate than was found in cement because it did not

T. Izumida; F. Kawamura; K. Chino; M. Kikuchi

1987-01-01

83

Raman Spectra of Yttrium Aluminum Borate Glasses and Glass-Ceramics  

NASA Astrophysics Data System (ADS)

Raman spectra of glasses and glass-ceramics in the Y_2O_3-Al_2O_3-B_2O3 system are reported. Glasses with B_2O3 contents ranging from 40 to 60 mole percent were prepared by melting 20 g of the appropriate oxide or carbonate powders in alumina crucibles at 1400^oC for 45 minutes. Subsequent heat treatments of the glasses at temperatures ranging from 600 to 700^oC were performed in order to induce nucleation and crystallization. It was found that Na_2CO3 added to the melt served as a nucleating agent and resulted in uniform bulk crystallization. The Raman spectra of the glasses are interpreted primarily in terms of vibrations of boron - oxygen structural groups. Comparison of the Raman spectra of the glass-ceramic samples with spectra of aluminate and borate crystalline materials reveal that these glasses crystallize primarily as yttrium aluminum borate, YAl_3(BO_3)_4.

Bradley, Juronica; Brooks, Montel; Crenshaw, Tiffany; Morris, Ayesha; Morgan, Steven

1997-11-01

84

Preparation and Characterization of Low-Dielectric Glass Composite with Aluminum Borate  

Microsoft Academic Search

The effect of aluminum borate ( Al18B4O33) on crystallization and thermal expansion of Pyrex borosilicate glass has been studied. X-ray diffraction (XRD) results show that with 40 vol% aluminum borate, the precipitation of cristobalite in the Pyrex borosilicate glass is completely inhibited. This result is further evidenced by the linear thermal expansion measurement in which, in contrast to the system

Jau-Ho Jean; Shiang-Po Hwang

1994-01-01

85

Elastic Constants and Thermal Properties of Lead-bismuth Borate Glasses  

Microsoft Academic Search

Systematic series of lead-bismuth borate glasses, where PbO, Bi2O3 and B2O3 content change for every series based on their weight percentage have been prepared. The ultrasonic and glass transition temperature (Tg) of this glass system have been studied using the Matec MBS-8000 Digital Signal Processing and conventional Differential Thermal Analysis (DTA) method. Elastic properties of the glass have been calculated

M. Hamezan; H. A. A. Sidek; A. W. Zaidan; K. Kaida; A. T. Zainal

2006-01-01

86

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

Microsoft Academic Search

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

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

2005-01-01

87

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

2013-05-02

88

Effect of Gamma Irradiation on Alkali Borate Glasses by EPR Spectroscopy  

NASA Astrophysics Data System (ADS)

Alkali borate glasses interesting application in safe nuclear fuel disposal were investigated under gamma irradiation. Glasses with different composition were prepared by conventional melt quench technique. In order to explore the defects created in the glass structure due to gamma irradiation, the EPR spectrum has been taken before and after high dose rate. The results revealed that the signal of involved paramagnetic species after irradiation shown slow time decay. Annealing procedure was performed to recover radiation damage.

Catallo, N.; Baccaro, S.; Colacicchi, S.; Gualtieri, G.; Ferrara, G.; Sharma, G.

2010-04-01

89

Paramagnetic hyperfine structure in 151Eu Mossbauer spectra of Eu2+ ions in borate glasses  

Microsoft Academic Search

Europium borate glasses containing 0.1-33 mol.% EuO have been prepared to study the 151Eu Mossbauer spectra. The results depend strongly on the concentration of Eu2+ ions in the glasses. In diluted systems, split patterns have been observed which originate from paramagnetic hyperfine interactions, as proved by the addition of Mn2+ ions to the glass. There is only a weak dependence

M. Winterer; E. Morsen; B. D. Mosel; W. Muller-Warmuth

1987-01-01

90

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

NASA Astrophysics Data System (ADS)

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; Senin, H. B.

2007-05-01

91

Rare-earth-doped transparent glass ceramics  

Microsoft Academic Search

Glass ceramics are a known class of polycrystalline ceramic materials, where, depending on the glass matrix and the particular crystalline phases, one can obtain materials with improved mechanical, thermal, electrical or optical properties. The characteristics and applications of optical glass ceramics are reviewed, with particular emphasis on rare-earth-doped transparent glass ceramics for photonics, including the search for new transparent glass

M Clara Gonçalves; Luís F Santos; Rui M Almeida

2002-01-01

92

Electrode properties of lithium borate glasses with high aluminum oxide contents  

Microsoft Academic Search

It was shown earlier that lithium borate glasses containing 20 mole % or more of AlâOâ have fairly high specificity for hydrogen ions. However, the dependence of the potential phi of the glass electrode on pH of the buffer solution (the phi vs. pH relationship) has linear regions with slope var theta in excess of the theoretical value (58 mV\\/pH

V. S. Bobrov; I. P. Lebedeva

1988-01-01

93

Dysprosium lithium borate glass mircrospheres for radiation synovectomy: The in vitro and in vivo performance evaluation  

Microsoft Academic Search

The radioactive dysprosium lithium borate glass (DyLB) microspheres with different glass compositions were prepared for radiation synovectomy. The biodegradability and biocompatibility of these DyLB microspheres were evaluated in vitro and in vivo. The DyLB microspheres studied in this work were partially biodegradable in a simulated body fluid (SBF), with the final weight loss of the microspheres in the range of

Di Zhao; Jing Yu; Wenhai Huang; Nai Zhou; Deping Wang; Wei Yin; Yaqing Chen

2010-01-01

94

Reaction of SiC{sub f}\\/SiC composites with a zinc borate glass  

Microsoft Academic Search

Two different types of SiC{sub f}\\/SiC composites were successfully joined using a zinc borate glass as a joining agent. The characterization of the joined specimens included XRD, DSC, DTA, SEM-EDS, macroporosimetry, and shear testing measurements. For both composites, the interfaces were continuous and crack-free, and a reaction occurred between the liquid glass and the composite`s surface. The large porosity of

P. Lemoine; M. Salvo; M. Ferrais; M. Montorsi; H. Scholz

1995-01-01

95

2pm\\/V in Poled Bismuth-Zinc-Borate High Index Glass  

Microsoft Academic Search

This paper demonstrates 2 pm\\/V in poled bismuth-zinc-borate glass planar waveguides. The innovative sample configuration, which provides a 4-fold improvement in the induced chi(2) compared to bulk glasses, is suggested by a poling model that takes into account both ionic and electronic conduction. The second-order nonlinearity chi(2) is found to be limited by the onset of nonlinear conductivity. Thus, this

C. Corbari; L. Chandru; I. C. S. Carvalho; O. Deparis; F. P. Mezzapesa; P. G. Kazansky; K. Sakaguchi

2009-01-01

96

X-ray photoemission study of Pr in zinc borate glasses  

Microsoft Academic Search

This work reports the X-ray photoelectron spectroscopy of a zinc borate glass activated by different concentrations (0, 1, 2, 4, and 8mol%) of Pr. The modification induced on the glass structure by the Pr ions was investigated, and a quantitative measure of the non-bridging-to-bridging-oxygen ratio around the Pr ion was obtained. The analysis of the O ls core line showed

G. Speranza; M. Ferrari; M. Bettinelli

1999-01-01

97

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

Microsoft Academic Search

Composites filled with a silicate glass (CSi) and a new borate glass (CB) were developed and compared in terms of their in\\u000a vitro behaviour both in acellular and cellular media. Acellular tests were carried out in SBF and the composites were characterized\\u000a by SEM-EDS, XRD and ICP. Biocompatibility studies were investigated by in vitro cell culture with MG-63 osteoblast-like and

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

2011-01-01

98

Reaction of SiC{sub f}/SiC composites with a zinc borate glass  

SciTech Connect

Two different types of SiC{sub f}/SiC composites were successfully joined using a zinc borate glass as a joining agent. The characterization of the joined specimens included XRD, DSC, DTA, SEM-EDS, macroporosimetry, and shear testing measurements. For both composites, the interfaces were continuous and crack-free, and a reaction occurred between the liquid glass and the composite`s surface. The large porosity of the chemical vapor deposited (CVI) composite allowed the glass to infiltrate the sandwich structure, the driving force being gaseous product pressurization and capillary surface forces.

Lemoine, P.; Salvo, M.; Ferrais, M.; Montorsi, M. [Polytechnic di Torino (Italy). Material Science and Chemical Engineering Dept.; Scholz, H. [Joint Research Centre, Ispra (Italy). Inst. for Advanced Materials

1995-06-01

99

Effects of Zinc Borate Addition on the Flammability Characteristics of Polyester, Vinyl Ester and Epoxy Glass Reinforced Plastics.  

National Technical Information Service (NTIS)

The effects of an inorganic fire-retardant additive, zinc borate, on flammability characteristics and smoke generation of glass reinforced polyester, vinyl ester and epoxy resins were evaluated. Information is presented on the flame spread index (ASTM E16...

R. M. Morchat

1993-01-01

100

Laser texturing of doped borosilicate glasses  

NASA Astrophysics Data System (ADS)

We describe a novel process of laser-assisted fabrication of surface structures on doped oxide glasses with heights reaching 10 - 13% of the glass thickness. This effect manifests itself as a swelling of the irradiated portion of the glass, and occurs in a wide range of glass compositions. The extent of such swelling depends on the glass base composition. Doping with Fe, Ti, Co, Ce, and other transition metals allows for adjusting the absorption of the glass and maximizing the feature size. In the case of bumps grown on borosilicate glasses, we observe reversible glass swelling and the bump height can increase or decrease depending on whether the consecutive laser pulse has higher or lower energy compared with the previous one. To understand the hypothetical mechanism, which includes laser heating of glass, glass melting, and directional flow, we explored density, refractive index, fictive temperature, and phase separation dynamics.

Streltsov, Alexander; Dickinson, James; Grzybowski, Richard; Harvey, Daniel; Logunov, Stephan; Ozturk, Alper; Sutherland, James; Potuzak, Marcel

2010-02-01

101

Visible and infrared spectroscopy of Pr3+ and Tm3+ ions in lead borate glasses  

NASA Astrophysics Data System (ADS)

The visible luminescence of Pr3+ and Tm3+ ions in lead borate glasses has been investigated as a function of activator concentration. The Judd-Ofelt analysis and the Inokuti-Hirayama model for energy transfer between activator ions have been applied for investigations of the radiative and non-radiative relaxation of the Pr and Tm excited states. Based on the luminescence decay curve analysis, the concentration quenching of the 1D2 emission of Pr3+ and 1G4 emission of Tm3+ ions has been attributed to cross-relaxation processes. The infrared spectroscopic measurements provide information on structural changes in the borate network initiated by optically active (Pr or Tm) ions. Contrary to the praseodymium ions, the thulium ions play an additional role as a glass-modifier in the PbO-B2O-Al2O3-WO3 composition.

Pisarski, W. A.; Pisarska, J.; Dominiak-Dzik, G.; Ryba-Romanowski, W.

2004-09-01

102

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

NASA Astrophysics Data System (ADS)

The ultrasonic velocity and attenuation measurements for different compositions of irradiated heavy metal oxide (HMO) borate glasses xBi2O3 (1-x) B2O3 (where x=0.25, 0.30, 0.35, 0.40, 0.45) has been investigated at room temperature (303 K) using pulse echo overlap method. The elastic moduli, Debye temperature, Poisson's ratio and other acoustical parameters have been obtained from experimental data. Structural changes after irradiation have been investigated by using FTIR spectroscopy and ultrasonic studies. As the changes are strongly dependent on the internal structure of the absorbing substance, in the present investigation ultrasonic velocities before and after ?-irradiation in bismuth borate glasses are measured as a function of composition, from which the structural changes in the network former B2O3 and modifier Bi2O3 due to irradiation are obtained.

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

2009-11-01

103

Zinc Oxide in Borate Glass-Forming Systems  

Microsoft Academic Search

Glasses based on the system ZnO - SrO - B2O3 with additional introduction of PbO, Al2O3, and Li2O are investigated; an elemental analysis of the heterogeneities is performed. The effect of ZnO on the physicochemical properties of glasses is considered. Fluxes with a decreased PbO content are developed.

N. M. Bobkova; S. A. Khot'ko

2005-01-01

104

Radiophotoluminescence from silver-doped phosphate glass  

Microsoft Academic Search

Glass dosimeter utilizing radiophotoluminescence (RPL) is one of accumulation type solid state dosimeters, which is based on luminescence phenomenon of silver (Ag+ ions)-doped phosphate glass exposed to ionizing radiation. In this study, to clarify the emission mechanism of yellow and blue RPL peaks, optical properties of Ag+-doped glass, such as optical absorption spectrum, RPL excitation spectrum before and after X-ray

Y. Miyamoto; Y. Takei; H. Nanto; T. Kurobori; A. Konnai; T. Yanagida; A. Yoshikawa; Y. Shimotsuma; M. Sakakura; K. Miura; K. Hirao; Y. Nagashima; T. Yamamoto

105

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

106

Gamma-ray attenuation coefficients in bismuth borate glasses  

NASA Astrophysics Data System (ADS)

Mass attenuation coefficients of glasses in the system: xBi2O3(1-x)B2O3 (x=0.30, 0.35, 0.40, 0.45 and 0.55) were determined at 356, 662, 1173 and 1332 keV photon energies using a narrow beam transmission method. Appreciable variations were observed in these coefficients due to changes in the chemical composition of glasses. These coefficients were then used to determine effective atomic numbers of glass samples, which were found to be constant with bismuth concentration and energy.

Singh, Kulwant; Singh, Harvinder; Sharma, Vishal; Nathuram, Rohila; Khanna, Atul; Kumar, Rajesh; Singh Bhatti, Surjit; Singh Sahota, Hari

2002-07-01

107

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

PubMed

Quaternary Ag(2)O-CaO-Bi(2)O(3)-B(2)O(3) glasses and glassceramics are investigated with regard to release behaviour and local structure. The dissolution behaviour in water and physiological serum shows that the cations are released rapidly or gradually and points out a multi-step process, generally characterised by higher rates in water than in physiological serum. The structural effect of silver addition to bismuth-borate glasses is observed from infrared spectroscopic data. The antibacterial activity of the investigated samples was tested on six bacterial media. PMID:17334702

Simon, V; Spinu, M; Stefan, R

2007-03-01

108

Decay behavior of Tb3+ green fluorescence in borate glasses  

NASA Astrophysics Data System (ADS)

In 70B2O3–30CaO–xTb2O3 glasses (x = 0.10–20.0 (mole fraction)) prepared by the melt-quenching method, the decay behavior of the green fluorescence due to the 5D4 ? 7F5 transition of Tb3+ ions was investigated by measuring the fluorescence spectra and time-resolved fluorescence spectra and then by analysis using the integrated intensity ratio of fluorescence bands due to the 5D3 ? 7FJ (J = 5, 4, and 3) and 5D4 ? 7FJ (J = 6, 5, 4, 3, 2, 1, and 0) transitions of Tb3+ ions, and the rate equations. In a 70B2O3–30CaO glass with high phonon energy, it was found that the 98.5% of all the excited electrons of Tb3+ ions were relaxed from the 5D3 to 5D4 level due to the multiphonon relaxation (MR) process. In addition, for x > 6.0, the green fluorescence rapidly decayed with increasing x, because the cross-relaxation process, (5D4 ? 7F0) ? 3(7F0 ? 7F6) among the excited Tb3+ ion at 5D4 and its three neighboring Tb3+ ions at 7F6 easily occurred. For x = 6, the cross-relaxation process, (5D3 ? 5D4) ? (7F0 ? 7F6) between Tb3+ ions was fully promoted and the cross-relaxation process, (5D4 ? 7F0) ? 3(7F0 ? 7F6) was repressed, and almost 100% of excited electrons in Tb3+ ions were available for the fluorescence due to the 5D4 ? 7FJ transitions. As a result, it was found that the 70B2O3–30CaO–6Tb2O3 glass had a potential of the green fiber laser.

Wada, Noriyuki; Kojima, Kazuo

2013-09-01

109

Structural relaxation kinetics of antimony borate glasses with covalent bonding character  

NASA Astrophysics Data System (ADS)

The structural relaxation kinetics in the glass transition for xSb2O3.(100-x)B2O3 glasses with covalent bonding character has been examined from viscosity and heat capacity measurements. These binary glasses have low glass transition temperatures, Tg=250-290 °C, but show a high thermal resistance against crystallization. The degree of fragility m estimated from the activation energy for viscous flow (E?=290-531 kJ mol-1) is m=29-51. The activation energy for enthalpy relaxation, ?H=297-602 kJ mol-1, is evaluated from the cooling rate dependence of the limiting fictive temperature. The ?H values are very close to the E? values, meaning that the decoupling between enthalpy relaxation and viscous flow is small. The values of Kovacs-Aklonis-Huchinson-Ramos (KAHR) parameter ? estimated from ?H/RTg2 are 0.13-0.25, where R is the gas constant. The glasses with 30-60 mol % Sb2O3 have very similar E?, m, ?H, and ? values. It has been demonstrated that the structural relaxation kinetics of the binary antimony borate glasses is affected by the boron coordination numbers (i.e., BO3 and BO4) and the covalent bonding character of Sb-O bonds, and consequently these glasses are regarded as a highly strong glass-forming system in the fragile/strong classification concept.

Honma, T.; Benino, Y.; Komatsu, T.; Sato, R.; Dimitrov, V.

2001-10-01

110

Effect of Eu 3+-doped on the luminescence properties of zinc borate nanoparticles  

Microsoft Academic Search

Zinc borate (?-Zn(BO2)2) nanocrystalline powders doped with Eu3+ ions had been prepared using co-precipitation method. ?-Zn(BO2)2:Eu3+ had been characterized by X-ray diffraction, TEM, FT-IR and luminescence spectra. They showed different emissions of Eu3+ corresponding to different transitions which lied in the wavelength range from 530 to 850nm. One particular transition 5D0?7F2 which was centered at 615nm had been known as

Yunhui Zheng; Yuning Qu; Yumei Tian; Chunguang Rong; Zichen Wang; Shengli Li; Xue Chen; Yuejia Ma

2009-01-01

111

Experimental Study of Neodymium Doped Glass Laser.  

National Technical Information Service (NTIS)

Experimental studies were performed on the effect of doping level and diameter of neodymium glass rods and reflectivity of the output mirror on the threshold energy and output energy of the laser. Data are presented of the energy output of glass rods havi...

A. J. Casella

1965-01-01

112

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

PubMed

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

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

2010-01-07

113

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

114

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

PubMed

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. PMID:24070293

Shaw, A; Ghosh, A

2013-09-21

115

Gadolinium zinc borate glass-based low temperature Co-fired ceramics  

Microsoft Academic Search

New microwave materials based on a gadolinium zinc borate (20ZnO?20Gd2O3?60B2O3) glass with typical Al2O3 filler have been investigated as a dielectric candidate for low temperature co-fired ceramic (LTCC) applications. The experimental\\u000a parameters, such as filler contents and firing temperature, were found to affect seriously densification, crystallization\\u000a and microwave dielectric properties. The presence of ZnAl2O4 and GdBO3 phases with an unexpected

Yeon Hwa Jo; Deuk Ho Yeon; Bhaskar C. Mohanty; Yong Soo Cho

2008-01-01

116

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 BaCl2:Eu2+ 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

117

Optimisation of lithium borate barium chloride glass-ceramic thermal neutron imaging plates  

NASA Astrophysics Data System (ADS)

Glass-ceramic thermal neutron imaging plates (NIPs) recently reported have been further developed for use in neutron radiography. The plate consists of nanocrystallites of the storage phosphor BaCl2:Eu2+ embedded within a neutron-sensitive lithium borate glass-matrix. A new generation of samples, enriched with both 10B and 6Li with thicknesses in the range 280 500 ?m have been studied. Neutron images were read out using a Fuji BAS2500 imaging plate scanner and the quality of the images obtained was comparable to those recorded on a commercial NIP. Details of the response to neutron-irradiation as well as the obtained spatial resolution of the images are presented. The neutron absorption and radiation hardness of the materials studied is also measured.

Appleby, G. A.; Vontobel, P.

2008-09-01

118

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

PubMed

Composites filled with a silicate glass (CSi) and a new borate glass (CB) were developed and compared in terms of their in vitro behaviour both in acellular and cellular media. Acellular tests were carried out in SBF and the composites were characterized by SEM-EDS, XRD and ICP. Biocompatibility studies were investigated by in vitro cell culture with MG-63 osteoblast-like and human bone marrow cells. The growth of spherical calcium phosphate aggregates was observed in acellular medium on all composite surfaces indicating that these materials became potentially bioactive. The biological assessment resulted in a dissimilar behavior of the composites. The CSi demonstrated an inductive effect on the proliferation of cells. The cells showed a normal morphology and high growth rate when compared to standard culture plates. Contrarily, inhibition of cell proliferation occurred in the CB probably due to its high degradation rate, leading to high B and Mg ionic concentration in the cell culture medium. PMID:21556978

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

2011-05-10

119

Boson peak in alkaline borate glasses: Raman spectroscopy, neutron scattering, and specific-heat measurements  

NASA Astrophysics Data System (ADS)

The dependence of the boson peak on the alkaline ion in modified borate glasses (M2O)0.14(B2O3)0.86 (M+=Li+,Na+,K+,Cs+) was analyzed by performing Raman spectroscopy, inelastic neutron scattering, and low-temperature specific-heat measurements. It is found that the distribution of vibrations merging into the boson peak shifts to higher frequency by going from cesium to lithium. A linear correlation between the boson peak frequency and the transverse sound velocity is evidenced. The dependence on the polarizing power of the metallic cation is analyzed, stemming from considerations about elastic moduli. These findings suggest a mainly transverse character of the excess vibrational modes in glasses.

D'Angelo, G.; Carini, G.; Crupi, C.; Koza, M.; Tripodo, G.; Vasi, C.

2009-01-01

120

Influence of drawing conditions on the properties of bismuth borate glass fibers  

NASA Astrophysics Data System (ADS)

In this study the influence of forming conditions, namely draw temperature and draw speed, on thermal properties of glass fibers of the composition 0.25 Bi2O3--0.75 B2O 3 were examined using mainly DSC measurements and confocal micro---Raman spectroscopy. Glass fibers were drawn at temperatures of 525, 550 and 575°C and draw speeds ranging from 1 to 10 m/sec. DSC measurements were performed to measure glass transition, heat capacity, fictive temperature, and pre--T g exotherm, both in strength and the onset. Concurrently micro---Raman measurements were used to identify the structural borate groups present in the fibers and their change with forming conditions. Several trends could be observed. As draw speed increases the glass transition decreases, indicating a more disordered structure. Pre--Tg exotherms show a local maximum at draw speeds of 4 m/s. Raman spectroscopy indicates the presence of [BiO6] octahedra that are becoming more distorted as the draw speed increases. The local maximum in both the pre--Tg exotherm and the corresponding Raman peak show that there is an optimal distortion. Pre--T g exotherm onset temperatures show a linear decrease with draw speeds. All this supports the conclusion that there is no major structural rearrangement. Heat capacity shows no overall trends of behavior dependant on forming conditions. These glass fibers also show a decrease in glass transition height during reheating that indicates a decreasing amount of glass. This can either be due to crystallization or phase separation. Finally the aspect ratio of the glass fibers seems to have a direct influence on heat capacity. As the aspect ratio increases the heat capacity of the glass fibers increases suddenly by a factor of two. The exact mechanism for this effect is unclear at this point.

Walker, Juergen

121

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

PubMed

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

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

2013-07-03

122

Effect of fluoride ions on the preparation of transparent glass ceramics based on crystallization of barium borates  

Microsoft Academic Search

Formation of transparent glass-ceramics based on crystallization of barium borate (BBO) crystals from BaO·B2O3 glass-systems, with and without addition of BaF2 has been investigated. Crystallization of glass-samples was done by controlled thermal heat-treatment, at nucleation and crystallization temperatures, for different times and rates. When the glasses were heat-treated at the nucleation temperature, transparent glass-ceramics containing 0.1–0.3?m BBO crystals were prepared.

S. A. M. Abdel-Hameed; N. A. Ghoniem; E. A. Saad; F. H. Margha

2005-01-01

123

Carbon nanotube-doped tellurite glasses  

NASA Astrophysics Data System (ADS)

In the past it was observed that buck ball doped glasses showed enhanced optical nonlinearities. However, carbon nanotubes are much more stable than buck ball and should be a better choice for that purpose. Therefore we decided to investigate the possibility to produce carbon nanotubes doped tellurite glasses and measured their optical nonlinearities. Tellurite glasses already have a larger nonlinearity compared to silica, and other, glasses. We produced TeO2-ZnO tellurite family glasses doped with multi wall Carbon Nanotube (CNT). The CNTs acquired from Carbolex were vigorously mechanically mixed with the tellurite glass precursors and melted in platinum crucible around 650°C in a controlled atmosphere inside an electrical induction furnace. We used the lowest temperature possible and controlled atmosphere to avoid the CNT oxidation. The glass melt was cast in a stainless steel and thermally treated at 300°C for 5 hours to relieve internal stresses. The samples were than cutted and polished to perform the optical characterization. We measured refractive index and thermo physical properties, such as vitreous transition Tg, crystallization onset Tx and melting Tf temperatures. Raman spectroscopy showed the possible presence of CNTs.

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

2008-02-01

124

Transition element-doped crystals in glass  

NASA Astrophysics Data System (ADS)

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

Pinckney, Linda R.; Beall, George H.

2001-11-01

125

Structural and time resolved emission spectra of Er3+: Silver lead borate glass  

NASA Astrophysics Data System (ADS)

The structural properties of Er3+: silver lead borate glass is assessed by means of SEM, X-ray mapping, EDS and Raman analysis. In order to verify the time dependency of emission spectra, steady-state luminescence spectroscopy (SSLS) and time-resolved emission spectroscopy (TRES) studies have been performed. The stimulated emission cross-sections for the NIR emission transition 4I13/2 ? 4I15/2 (1535 nm) at 970 nm excitation are reported. The decay times were obtained by fitting one (?m = 0.301 ms) and two (?m1 = 0.141 ms, ?m2 = 0.368 ms) distributions for the NIR transition. Furthermore, by making use of TRES measurements the decay associated spectra were obtained allowing the time dependency for the different emission bands to be elucidated.

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

2011-08-01

126

Sensitized red luminescence from Bi3+ co-doped Eu3+: ZnO-B2O3 glasses  

NASA Astrophysics Data System (ADS)

Photoluminescence properties of Bi3+ co-doped Eu3+ containing zinc borate glasses have been investigated and the results are reported here. Bright red emission due to a dominant electric dipole transition 5D0?7F2 of the Eu3+ ions has been observed from these glasses. The nature of Stark components from the measured fluorescence transitions of Eu3+ ions reveal that the rare earth ions could take the lattice sites of Cs or lower point symmetry in the zinc borate glass hosts. The significant enhancement of Eu3+ emission intensity by 346 nm excitation (1S0?3P1 of Bi3+ ions) elucidates the sensitization effect of co-dopant. The energy transfer mechanism between sensitizer (Bi3+) and activator (Eu3+) ions has been explained.

Sontakke, Atul D.; Tarafder, Anal; Biswas, Kaushik; Annapurna, K.

2009-11-01

127

On the Electron Paramagnetic Resonance Studies in Mixed Alkali Borate Glasses  

SciTech Connect

Mixed alkali effect in oxide based glasses is one of the current research activity and studies on the behavior of spectroscopic parameters in these systems are quite important to understand the basic nature of this phenomenon. EPR studies of mixed alkali glasses Li{sub 2}O-K{sub 2}O-ZnO-B{sub 2}O{sub 3} doped with Fe{sup 3+} and Mn{sup 2+} were carried out at room temperature. The EPR spectra show typical resonances of d{sup 5} system (Fe{sup 3+} and Mn{sup 2+}) in all the measured glass specimens. Evaluated hyperfine constant, number of paramagnetic centers and paramagnetic susceptibility values show deviation from the linearity with the progressive substitution of the Li ion with K in glass network.

Padmaja, G. [Department of Physics, Kakatiya University, Warangal 506009 (India); Reddy, T. Goverdhan [Graphene Research Institute and Department of Physics, Sejong University, Seoul 143-747 (Korea, Republic of); Kistaiah, P. [Department of Physics, Osmania University, Hyderabad 500 007 (India)

2011-10-20

128

Optical properties of Er 3+ ions in lithium borate glasses and comparative energy level analyses of Er 3+ ions in various glasses  

Microsoft Academic Search

The electronic structure of Er3+ ions are studied in the following lithium borate (LBO) glasses: Li2CO3 + H3BO3 and RCO3 + Li2CO3 + H3BO3 (R = Mg, Ca, Sr and Ba). The electronic structure of Er3+(4f11) in these glasses as well as the data that are available for other systems in the literature are also analyzed in terms of a

A. Renuka Devi; C. K. Jayasankar

1996-01-01

129

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.

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

130

Molecular dynamics investigation of lithium borate glasses: Local structure and ion dynamics  

NASA Astrophysics Data System (ADS)

The effect of alkali content and temperature on the microstructure of lithium borate glasses, xLi2O-(1-x)B2O3, has been investigated for glass compositions x=0.2-0.5 and temperatures up to 1250 K. The molecular dynamics technique has been applied, with Ewald summation and periodic boundary conditions, to a collection of ca. 256 particles confined in a primitive cubic cell and interacting through a Born-Mayer-Huggins-type potential augmented with three-body angular terms. The short-range order (SRO) structure was found to consist of boron-oxygen tetrahedral, BØ-4 [Ø=bridging oxygen atom (BO)], and triangular units with variable number of nonbridging oxygen (NBO) atoms, BØ3, BØ2O-, and BØO2-2 (O-=NBO). The relative abundance of SRO units was determined and found to depend on both glass composition and temperature. Increasing Li2O content at constant temperature or increasing temperature at a fixed composition was shown to cause rearrangements of the SRO structure and to lead towards BØO2-2 units in the range of compositions and temperatures investigated. Such changes were expressed in terms of chemical equilibria involving the SRO units. The local environments hosting the Li ions were investigated and distinguished in two main types: the first type of site is formed by BO's, while the second type involves the participation of NBO's. The vibrational response of Li ions in the two types of site was computed and found to correlate very well with the experimental far-infrared profiles. Calculation of diffusion coefficients of Li ions showed that diffusion is carried out predominantly through NBO sites. In addition, glass regions rich in Li/NBO were found to develop with increasing lithium oxide content and to percolate eventually into microchannels suitable for ion migration.

Varsamis, Cristos-Platon E.; Vegiri, Alice; Kamitsos, Efstratios I.

2002-03-01

131

Absorption and luminescence spectroscopy of Nd 3+ and Er 3+ in a zinc borate glass  

Microsoft Academic Search

4ZnO · 3B2O3 glasses doped with Nd3+ and Er3+ were investigated by optical spectroscopy. Emission transition probabilities, radiative life-times and fluorescence branching ratios for several excited states of the Nd3+ and Er3+ ions were estimated from the room temperature absorption spectra. The stimulated emission cross sections ?p for the near infrared laser transitions of Nd3+ and Er3+ were obtained from

Maurizio Casarin

1996-01-01

132

Effect of the sintering temperature on the structural and magnetic parameters of strontium ferrites doped with kaolin and barium borate  

SciTech Connect

This paper presents the results of studies of the effect of the sintering temperature of strontium ferrites (doped with 1.2 mass % kaolin and barium borate) on their properties. The fine crystalline structure of anisotropic and demagnetized strontium ferrites doped with kaolin was studied with the help of the Moessbauer effect. Fe-57 nuclei, occupying 4f2 and 2a octahedral positions, respectively, in the hexagonal and spinel blocks, have the highest magnetic fields and quadrupole shifts. The effect of the sintering temperature on the physical properties of the ferrites studied is linked to changes in the microstructure and porosity of the samples.

Pashchenko, V.P.; Kostyagina, O.A.; Lisitsyn, S.M.; Prokopenko, A.K.; Selivanova, L.Y.; Serebro, D.Y.

1986-01-01

133

The effect of V 2O 5 on alkaline earth zinc borate glasses studied by EPR and optical absorption  

Microsoft Academic Search

10wt% SrO:30wt% ZnO:60wt% B2O3 incorporated with different vanadyl concentrations were studied by means of electron paramagnetic resonance (EPR) and optical absorption techniques. The spin-Hamiltonian parameters (g and A), bonding parameters (?2 and ?2?2) and Fermi contact interaction parameter K have been calculated. The values of spin-Hamiltonian parameters indicate that the VO2+ ions in strontium zinc borate glasses were present in

B. Sumalatha; I. Omkaram; T. Rajavardhana Rao; Ch. Linga Raju

134

Characterisation of Erbium Doped Phosphate Glass  

SciTech Connect

A series of erbium doped phosphate glass has been successfully fabricated, and the determination of their density and luminescence properties has been carried out. It is particularly interesting to study the effect of modifying oxides to the properties of the glass. The glass density reduces with the increasing content of Na{sub 2}O. The emission spectra from luminescence spectroscopy resolved six emission peaks from the excitation wavelength of 336.8 nm (3.69 eV). The emission of {sup 4}F{sub 7/2} gives two emission peaks, where the peak near 482 nm shows a higher intensity and the peak near 491 nm gives a weak emission spectra.

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

2010-03-11

135

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

PubMed

Previous studies have evaluated the capacity of porous scaffolds composed of a single bioactive glass to regenerate bone. In the present study, scaffolds composed of a mixture of two different bioactive glasses (silicate 13-93 and borate 13-93B3) were created and evaluated for their response to osteogenic MLO-A5 cells in vitro and their capacity to regenerate bone in rat calvarial defects in vivo. The scaffolds, which have similar microstructures (porosity=58-67%) and contain 0, 25, 50 and 100wt.% 13-93B3 glass, were fabricated by thermally bonding randomly oriented short fibers. The silicate 13-93 scaffolds showed a better capacity to support cell proliferation and alkaline phosphatase activity than the scaffolds containing borate 13-93B3 fibers. The amount of new bone formed in the defects implanted with the 13-93 scaffolds at 12weeks was 31%, compared to values of 25, 17 and 20%, respectively, for the scaffolds containing 25, 50 and 100% 13-93B3 glass. The amount of new bone formed in the 13-93 scaffolds was significantly higher than in the scaffolds containing 50 and 100% 13-93B3 glass. While the 13-93 fibers were only partially converted to hydroxyapatite at 12weeks, the 13-93B3 fibers were fully converted and formed a tubular morphology. Scaffolds composed of an optimized mixture of silicate and borate bioactive glasses could provide the requisite architecture to guide bone regeneration combined with a controllable degradation rate that could be beneficial for bone and tissue healing. PMID:23827095

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

2013-07-01

136

Effect of cation sizes on tunnelling states, relaxations and anharmonicity of alkali borate glasses  

NASA Astrophysics Data System (ADS)

The relaxation losses and the corresponding velocity variations, observed at ultrasonic frequencies in (M2O)0.14(B2O3)0.86 alkali borate glasses (M = Li, K, Cs) between 1.5 and 300 K, have been modelled by an asymmetric double-well potential model having a distribution of both the barrier potential and the asymmetry. It is shown that the relaxation strength C* and the spectral density of asymmetries f0 decreases markedly with decreasing cation size. Below 10 K the sound attenuation is regulated by the phonon-assisted relaxation of tunnelling systems and exhibits a tunnelling strength C, ranging between 10-4 and 10-3. At variance with the behaviour observed for C*, C slightly increases with decreasing cation size and is more than one order of magnitude smaller than C*. It is concluded that, differently from classical relaxing states, tunnelling systems are independent of bond strengths and of structural changes characterizing a glassy network, confirming their inherent universality. Above about 120 K the ultrasonic velocity is mainly regulated by vibrational anharmonicity and shows a nearly linear decrease as the temperature is increased, the slope scaling with the cation size. Taken together, the observations point to the existence of a distinct correlation between anharmonicity and local mobility in the glassy network.

Carini, Giovanni; Carini, Giuseppe; Tripodo, Gaspare; Bartolotta, Antonio; Di Marco, Gaetano

2006-03-01

137

Physical and structural properties of Nd3+ doped BaO-ZnO-B2O3 glasses  

NASA Astrophysics Data System (ADS)

Nd3+ doped Barium-Zinc-Borate glasses with composition xNd2O3-(100-x)[0.1BaO-0.4ZnO-0.5B2O3]x = 0,0.5,1.0,1.5,2.0 have been prepared by melt-quenching method. X-Ray Diffractogram of the synthesized glass samples confirms the amorphous nature. The physical properties i.e. density and molar volume have been measured and both increases with increase in Nd3+ content. Glass transition temperature have been measured using DSC and found to be increase with Nd3+ content shows good thermal stability. Analysis of FTIR spectra estimate the presence of tetrahedral coordination of Zn (i.e. ZnO4) in synthesized glasses. The basic structural units [BO3] and [BO4] are observed in glasses under study.

Nanda, Kirti; Kundu, R. S.; Punia, R.; Parmar, R.; Kishore, N.

2013-06-01

138

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

139

Effect of rare earth (Pr2O3, Nd2O3, Sm2O3, Eu2O3, Gd2O3 and Er2O3 ) on the acoustic properties of glass belonging to bismuth borate system  

NASA Astrophysics Data System (ADS)

Bismuth borate glasses doped with some rare earth ions were studied with respect to the density, molar volume and the elastic moduli, Poisson’s ratio, Debye temperature, microhardness, softening temperature, acoustic impedance, diffusion constant and latent heat of melting. Ultrasonic velocities were measured by the pulse echo overlap technique at a frequency of 10 MHz and at room temperature. From these velocities and density values, various elastic moduli were calculated. The correlation of elastic stiffness, the cross link density, and the fractal bond connectivity of these glasses are discussed. The derived experimental values of shear modulus, bulk modulus, Young’s modulus, and Poisson’s ratio for our glasses are compared with the theoretically calculated values in terms of the bond compression model and Makishima Mackenize theory.

Yousef, El Sayed; El-Adawy, Amin; El-Kheshkhany, N.

2006-07-01

140

The effect of V2O5 on alkaline earth zinc borate glasses studied by EPR and optical absorption  

NASA Astrophysics Data System (ADS)

10 wt% SrO:30 wt% ZnO:60 wt% B2O3 incorporated with different vanadyl concentrations were studied by means of electron paramagnetic resonance (EPR) and optical absorption techniques. The spin-Hamiltonian parameters (g and A), bonding parameters (?2 and ?2?2) and Fermi contact interaction parameter K have been calculated. The values of spin-Hamiltonian parameters indicate that the VO2+ ions in strontium zinc borate glasses were present in octahedral sites with tetragonal compression. The spin concentration (N) participating in resonance was calculated as a function of temperature (93-273 K) for strontium zinc borate glass sample containing 0.9 wt% of VO2+ ions and the activation energy (Ea) was calculated. From the EPR data, the paramagnetic susceptibility (?) was calculated at various temperatures and the Curie constant (C) was evaluated from the 1/?-T graph. The optical absorption spectra of VO2+ ions in these glasses show two bands corresponding to the transitions 2B2g ? 2B1g and 2B2g ? 2Eg in the order of decreasing energy respectively. The optical band gap energies (Eopt) and Urbach energy (?E) have been determined from their ultraviolet edges. The theoretical values of optical basicity (?th) of these glasses have also been evaluated.

Sumalatha, B.; Omkaram, I.; Rajavardhana Rao, T.; Linga Raju, Ch.

2011-12-01

141

IR luminescence in bismuth-doped germanate glasses and fibres  

NASA Astrophysics Data System (ADS)

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.

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

2013-02-01

142

Determination of complex-specific heat and fragility of sodium borate glasses by temperature-modulated DSC  

Microsoft Academic Search

The frequency dependences of the complex-specific heat of the sodium borate glasses, xNa2O·(100 ? x)B2O3, where x denotes molar concentration of Na2O, have been investigated by temperature-modulated DSC. The temperature dependences of ?-relaxation time have been analyzed\\u000a in Angell plot, and the fragility index has been determined. The composition dependence of the fragility index has been discussed\\u000a on the basis of the

Yasuteru Fukawa; Yu Matsuda; Mitsuru Kawashima; Seiji Kojima

2010-01-01

143

Luminescence of Ce3+ in some heavy oxide glasses  

NASA Astrophysics Data System (ADS)

The luminescence of Ce3+ in borate, borosilicate, phosphate and germanate glasses containing La2O3,BaO, Ta2O5,Nb2O5 were measured by ultraviolet-visible excitation with an aim of identifying the effect of hosts on the spectroscopic properties of Ce3+ in these glasses. Meanwhile, the scintillating luminescence of some of these borate glasses were determined by x-ray radiation in order to understand the possibility of borate glass as Ce3+-doped dense glass scintillator.

Jiang, Chun; Zhang, Junzhou; Gan, Fu-Xi

1998-08-01

144

Scintillating luminescence of cerium-doped dense oxide glass  

NASA Astrophysics Data System (ADS)

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

Jiang, Chun; Zhang, Junzhou; Gan, Fu-Xi

1999-10-01

145

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

NASA Astrophysics Data System (ADS)

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

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

2008-12-01

146

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

147

Photosensitivity of rare-earth-doped ZBLAN fluoride glasses  

Microsoft Academic Search

We have performed experiments to elucidate the mechanism of photosensitivity in rare-earth-doped fluorozirconate (ZBLAN) glasses. Glasses doped with Ce, Tb, Tm, and Pr were studied. Permanent holographic gratings were written in bulk samples using 248 nm light, with the strongest gratings observed in Ce:ZBLAN. Ultraviolet (UV) induced changes in both absorption and electron spin resonance (ESR) spectra were observed. In

Glen M. Williams; Tsung-Ein Tsai; Celia I. Merzbacher; E. Joseph Friebele

1997-01-01

148

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

149

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  

Microsoft Academic Search

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

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

2011-01-01

150

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

PubMed Central

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

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

2010-01-01

151

Nonlinear optical properties of Ho3+-doped borosilicate glass  

NASA Astrophysics Data System (ADS)

Using an improved borosilicate glass with small third-order optical nonlinearities, i.e., nonlinear refractive index (NLRI) and nonlinear absorption coefficient (NLAC), as the matrix and comparative glass, two types of Ho3+-doped glass are prepared with a solid-phase smelting process at a relatively low temperature, and their third-order optical nonlinearities are measured by the closed-aperture Z-scan technique using nanosecond laser pulses at 532nm wavelength. It is found that the matrix glass possesses a positive third-order NLRI and a positive third-order NLAC, and both the third-order NLRI and NLAC of Ho3+-doped glasses are one order larger than those of the matrix glass, respectively. Also, an open-aperture Z-scan experiment and an optical limiting experiment further demonstrate that the Ho3+-doped glasses have a high third-order NLAC. All the experimental results show that this Ho3+-doped glasses have good protection performance for the 532nm-laser.

Fu, Jian; Sun, Li; Liu, Xiao-Dong; Song, Zhao-yuan; Chen, Yue-e.; Liu, Dong-ping

2008-11-01

152

Broadband optical amplification in Bi-doped germanium silicate glass  

NASA Astrophysics Data System (ADS)

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

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

2007-08-01

153

Nonlinear optical properties of Ho3+-doped borosilicate glass  

Microsoft Academic Search

Using an improved borosilicate glass with small third-order optical nonlinearities, i.e., nonlinear refractive index (NLRI) and nonlinear absorption coefficient (NLAC), as the matrix and comparative glass, two types of Ho3+-doped glass are prepared with a solid-phase smelting process at a relatively low temperature, and their third-order optical nonlinearities are measured by the closed-aperture Z-scan technique using nanosecond laser pulses at

Jian Fu; Li Sun; Xiao-Dong Liu; Zhao-yuan Song; Yue-e. Chen; Dong-ping Liu

2008-01-01

154

Orange emission in Pr3+-doped fluoroindate glasses  

NASA Astrophysics Data System (ADS)

We synthesize and study the properties of praseodymium doped fluoroindate glasses. Glass compositions with praseodymium molar concentrations up to 5% were obtained with good optical quality. Thermal, optical, and luminescence properties are investigated. Judd-Ofelt analysis is used to determine radiative lifetime and emission cross-section of the orange transition originating from the 3P0 level. We find that these glasses are good candidates for the realization of blue diode laser pumped orange lasers for quantum information processing applications.

Manzani, Danilo; Pabœuf, David; Ribeiro, Sidney J. L.; Goldner, Philippe; Bretenaker, Fabien

2013-01-01

155

EPR study of Yb-doped irradiated glasses  

NASA Astrophysics Data System (ADS)

Yb3+ reduction under ? and ? irradiation has been studied in aluminoborosilicate glasses by EPR spectroscopy. From the Yb3+ EPR line variation, we demonstrate that more than one Yb3+ sites coexist in the pristine Yb-doped glasses. Reduction of Yb3+ into Yb2+ is observed for all integrated doses and Yb doping contents. For doses higher than 108 Gy, an Yb3+ ion environment change occurs, this change is correlated with a stabilization of the reduced Yb2+ state. The paramagnetic defect concentration displays a linear variation as a function of the logarithm of the dose. The glass doping with Yb2O3 leads to a substantial decrease of the defect concentration as well as a modification in the relative proportion of the defects produced. In particular, Yb doping tends to increase the relative content of Oxy defects.

Ollier, N.; Planchais, R.; Boizot, B.

2008-06-01

156

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

157

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

2012-08-27

158

New scintillator: cerium-doped dense oxide glass  

NASA Astrophysics Data System (ADS)

The properties of high rare-earth-containing borosilicate glass have been investigated to assess the potential for using this material to construct electromagnetic calorimeters for particle physics. We report here on measurements of scintillation yield, transmission and decay time, on large blocks of Ce3+-doped Gd2O3-based glasses, the samples were excited by a high energy X-ray beam and the associated scintillation yield and decay time were measured. The optical transmission of the samples was measured. It was observed that scintillation yield of present scintillation glass is 10 - 20% of BGO scintillation yield, decay time is in range of 60 - 80 ns, glass density is 5.40 g/cm(superscript 3$. It was concluded that higher density and availability and low cost makes this glass become promising candidate for cerium doped dense scintillator.

Jiang, Chun; Zeng, Qingji; Gan, Fuxi

2000-10-01

159

Scintillation properties of cerium-doped germanate glass  

NASA Astrophysics Data System (ADS)

The properties of high rare-earth-containing germanate glass have been investigated to assess the potential for using this material to construct electromagnetic calorimeters for particle physics. We report here on measurements of scintillation yield, transmission and decay time, on large blocks of Ce3+-doped Gd2O3-based glasses, the samples were excited by a high energy X-ray beam and the associated scintillation yield and decay time was measured. The optical transmission of the samples was measured. It was observed that scintillation yield of present scintillation glass is 20 - 30% of BGO scintillation yield, decay time is in range of 60 - 90 ns, glass density is 5.75 g/cm3. It was concluded that higher density and availability and low cost make this glass become promising candidate for cerium doped dense scintillator.

Jiang, Chun; Zeng, Qingji; Gan, Fuxi

2000-11-01

160

Energy Transfer Studies of Tb Doped Sol-gel glasses  

NASA Astrophysics Data System (ADS)

We present recent studies of the effects of energy transfer on the time evolution of Tb^3+ emission lines in sol-gel glasses. Utilizing a multichannel analyzer we are now able to measure the lifetimes of weak emission lines from the sol-gel glasses. The measured decay signals have been analyzed using theoretical models to gain insight into the distribution of the rare earth ions in doped glasses. We will discuss the observed energy dynamics as the result of chemical treatments of the glass and fabrication variables.

Sanchez, Freddy; Montejo, Genderzon; Wenzlau, Dylan; Hoffman, Kurt

2010-10-01

161

Study of photoluminescence quenching in Er 3+-doped tellurite glasses  

Microsoft Academic Search

Erbium-doped tellurite glasses (TeO2–ZnO–Na2O3: Er3+ (TZNE)) were elaborated from the melt-quenching method. Various spectroscopic parameters were obtained to evaluate their dependence and the potential of the samples as a laser material in the eye-safe laser wavelength (1.53?m) as a function of the Er3+ concentration. The dependence of infrared photoluminescence (PL) spectra on doping concentration shows a quenching of the PL

I. Jlassi; H. Elhouichet; M. Ferid; R. Chtourou; M. Oueslati

2010-01-01

162

Spectroscopy of bismuth-doped lead–aluminum–germanate glass and yttrium–aluminum–silicate glass  

Microsoft Academic Search

In this work we make a comparison between the spectroscopy of bismuth-doped lead–aluminum–germanate (Bi:PAG) glass and bismuth-doped yttrium–aluminum–silicate (Bi:YAS) glass. We report the variation in Bi absorption, emission and lifetime as the PbO, Bi2O3 and Y2O3 contents of the two glass systems were varied. As PbO and Y2O3 contents were increased the absorption strength of Bi decreased in both Bi:PAG

M. A. Hughes; T. Suzuki; Y. Ohishi

2010-01-01

163

Observation of UV induced absorption changes in tellurite and selected doped silica glasses  

Microsoft Academic Search

With the advent of fiber Bragg gratings and integrated optics, photosensitivity and photoinduced refractive index changes in glasses have become an important area of study. Several glasses including compositions of Eu doped silicates, cerium doped silicates, and germanium doped silicates exhibit UV induced refractive index changes. Its reasonable to expect that many glass compositions will also show refractive index changes

J. D. Prohaska; R. T. Garton; J. S. Wang; F. Wu; E. Snitzer

1994-01-01

164

Raman spectroscopy studies of Er 3+-doped zinc tellurite glasses  

Microsoft Academic Search

Er3+-doped tellurite-based glasses have been investigated using Raman spectroscopy. The study is aimed to determine the structural characteristics of systems with broad Er3+ emission bands. In the Er2O3 concentration 0.5–4mol% range studied, experimental results showed that adding erbium ions to zinc tellurite glass converts TeO4 trigonal bipyramid (tbp) units into TeO3 trigonal pyramid (tp) groups. A Raman band, associated with

N. Jaba; A. Mermet; E. Duval; B. Champagnon

2005-01-01

165

New scintillator: cerium-doped dense oxide glass  

Microsoft Academic Search

The properties of high rare-earth-containing borosilicate glass have been investigated to assess the potential for using this material to construct electromagnetic calorimeters for particle physics. We report here on measurements of scintillation yield, transmission and decay time, on large blocks of Ce3+-doped Gd2O3-based glasses, the samples were excited by a high energy X-ray beam and the associated scintillation yield and

Chun Jiang; Qingji Zeng; Fuxi Gan

2000-01-01

166

Scintillation properties of cerium-doped germanate glass  

Microsoft Academic Search

The properties of high rare-earth-containing germanate glass have been investigated to assess the potential for using this material to construct electromagnetic calorimeters for particle physics. We report here on measurements of scintillation yield, transmission and decay time, on large blocks of Ce3+-doped Gd2O3-based glasses, the samples were excited by a high energy X-ray beam and the associated scintillation yield and

Chun Jiang; Qingji Zeng; Fuxi Gan

2000-01-01

167

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

Microsoft Academic Search

The connection between bulk glass properties and network topology is now well established. However, there has been little attention paid to the impact of network topology on the surface properties of glass. In this work, we report the impact of the network topology on both the transport properties (such as cationic inward diffusion) and the mechanical properties (such as hardness)

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

2010-01-01

168

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

169

Direct experimental determination of the crossover frequency between phonon and fracton regimes and its scaling behavior in superionic silver borate glasses  

Microsoft Academic Search

We determined the crossover frequency omegaco between phonon and fracton regimes from the study of the low-frequency inelastic light scattering in superionic borate glasses of the type (AgI)x(Ag2O.B2O3)1-x. The scaling of omegaco with the fractal characteristic length was studied by variation of the AgI concentration x. We thus obtained the diffusion coefficient scaling exponent theta and the spectral dimensionality d~

A. Fontana; F. Rocca; M. P. Fontana

1987-01-01

170

Optical band gap studies and estimation of two photon absorption coefficient in alkali bismuth borate glasses  

NASA Astrophysics Data System (ADS)

The optical absorption spectra of the glasses with composition xBi(2)O(3) . (30 - x)R2O . 70B(2)O(3) (R=Li, Na, K) and xBi(2)O(3) . (70 - x)B2O3 . 30Li(2)O (0 less than or equal to x less than or equal to 20) have been recorded in the wavelength range 350-650 nm. The glass samples were prepared by the normal melt-quench technique. The fundamental absorption edge for all the series of glasses is analyzed using the theory of Davis and Mott. The position of absorption edges and the values of optical band gap are dependent on the mol% of Bi2O3. The absorption in these glasses is associated with indirect transitions. The values of Urbach's energy and band tailing parameters are reported. The two photon absorption coefficient,, in these glasses has also been estimated from the optical band gap and its value ranges from 1.3 to 11.6 cm/GW. The relationship between beta and glass composition has also been discussed in terms of the electronic structure of the glass system.

Agarwal, A.; Seth, V. P.; Sanghi, S.; Gahlot, P.; Goyal, D. R.

2003-11-01

171

Crystallization behavior of rare-earth doped fluorochlorozirconate glasses.  

PubMed

A series of fluorochlorozirconate (FCZ) glasses, each doped with a different rare-earth, was prepared and examined to determine thermal stability and activation energy, Ea , of the dopant dependent BaCl2 crystallization. Non-isothermal differential scanning calorimetry (DSC) measurements were done to investigate the endothermic and exothermic reactions upon heat treatment of the glass samples. In comparison to the rare-earth free FCZ glass, significant changes in the Hruby constant, Hr , and Ea were found due to the addition of a rare-earth and also between the individual dopants. PMID:23493406

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

2010-12-18

172

Crystallization behavior of rare-earth doped fluorochlorozirconate glasses  

PubMed Central

A series of fluorochlorozirconate (FCZ) glasses, each doped with a different rare-earth, was prepared and examined to determine thermal stability and activation energy, Ea, of the dopant dependent BaCl2 crystallization. Non-isothermal differential scanning calorimetry (DSC) measurements were done to investigate the endothermic and exothermic reactions upon heat treatment of the glass samples. In comparison to the rare-earth free FCZ glass, significant changes in the Hruby constant, Hr, and Ea were found due to the addition of a rare-earth and also between the individual dopants.

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

2012-01-01

173

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

Microsoft Academic Search

Vanadium doped gallium lanthanum sulphide glass (V:GLS) displays three absorption bands at 580, 730, and 1155 nm identified by photoluminescence excitation measurements. Broad photoluminescence, with a full width at half maximum of ~500 nm, is observed peaking at 1500 nm when exciting at 514, 808, and 1064 nm. The fluorescence lifetime and quantum efficiency at 300 K were measured to

M. Hughes; H. Rutt; D. Hewak; R. J. Curry

2007-01-01

174

Development of bismuth doped lead-aluminum-zinc-germanate glass as a broadband optical gain medium  

Microsoft Academic Search

In this paper we present the development process of a glass based on bismuth and aluminum co-doped germanate (GAB) glass. Other workers have demonstrated broadband optical gain in GAB glass. We found the addition of PbO to this glass (GAPB glass) increased the quantum efficiency (QE). Excitation of GAPB glass at 808 nm produced emission peaking at 1230 nm with

M. Hughes; T. Suzuki; Y. Ohishi

2009-01-01

175

Evidence of anomalous intermediate-range ordering in superionic borate glasses from neutron diffraction  

NASA Astrophysics Data System (ADS)

Evidence of intermediate-range ordering in a superionic (AgI)x(Ag2O+2B2O3)1-x glass is presented. Comparative neutron-diffraction measurements were performed in a low (x=0.1) and a high (x=0.6) -AgI-concentration glass. A strong and sharp diffraction peak at an anomalously low Q value of 0.8 Å-1 is observed for the x=0.6 glass, which is not present in the x=0.1 glass. The phenomenon is attributed to an ordering of the intermediate-range structure, due either to formations of AgI clusters or to density deficits in the boron-oxygen network.

Börjesson, L.; Torell, L. M.; Dahlborg, U.; Howells, W. S.

1989-02-01

176

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

177

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

NASA Astrophysics Data System (ADS)

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

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

2012-10-01

178

Photosensitivity of Ge-doped phosphate glass to 244 nm irradiation  

SciTech Connect

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

Suzuki, S.; Schuelzgen, A.; Sabet, S.; Moloney, J. V.; Peyghambarian, N. [College of Optical Sciences, University of Arizona, Tucson, Arizona 85721 (United States)

2006-10-23

179

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

Microsoft Academic Search

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

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

2008-01-01

180

Spectral studies (Judd-Ofelt theory) of Er3+ in zinc bismuth borate glasses  

NASA Astrophysics Data System (ADS)

Glasses with compositions 20ZnO.xBi2O3.(79.5-x)B2O3 (x = 25, 30, 35 mol%) containing 0.5 mol% of Er3+ ions were prepared by melt-quench technique (1150 °C in air). The spectroscopic properties of the glasses were investigated using optical absorption spectra and fluorescence spectra. The Judd-Ofelt intensity parameters ?? (? = 2,4,6) were determined from the spectral intensities of absorption bands in order to calculate the spectroscopic properties of the prepared glass samples. All intensity parameters (??) decrease with increase in Bi2O3 content and the effect is found to be most pronounced for ?2 values.

Pal, I.; Agarwal, A.; Sanghi, S.; Aggarwal, M. P.

2011-12-01

181

Structure of zinc-borate low-melting glasses derived from IR spectroscopy data  

Microsoft Academic Search

The IR spectra of glasses of the ZnO—SrO—B2O3 system with constant additions of PbO, Al2O3, and Li2O (20 mol. % in sum) were studied. It is established that on replacement of B2O3 by ZnO, the structure of the glasses is characterized by the presence of groupings with the bridge bonds BIII— O—BIII, BIII—O—BIV, BIV—O—BIV and end groups BIII— O?; ZnO

N. M. Bobkova; S. A. Khot’ko

2005-01-01

182

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-xBi2O3-25MgHPO4-24B2O3-1Er2O3 (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 (?4f), 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

183

The effect of CuO and MgO impurities on the optical properties of lithium potassium borate glass  

NASA Astrophysics Data System (ADS)

Previous study proved the efficiency of copper as one of the most luminescent activators. In this work, Li2CO3-K2CO3-H3BO3 (LKB) glasses co-doped with copper oxide (CuO) and magnesium oxide (MgO) have been prepared by chemical quenching technique. Two techniques have been applied to investigate the effect of co-dopants on the physical and optical properties of the new glass network. The X-ray Diffraction (XRD) results showed the amorphous nature of the sample. Fourier transform infrared (FTIR) spectra, 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 co-doped ions in the glass matrix. The exchange in the concentration of magnesium and copper ions illustrated the great effect of magnesium as a co-dopant on the Photoluminescence (PL) emission of LKB doped with copper oxide. Due to the change in the copper concentration, a broad green emission with intensity of around 300 (a.u) has been observed. Enhancement of about three times has been shown with the increment of 0.1 mol% of CuO and MgO as a co-dopant technique. It is well known that magnesium oxide alone does not show strong-luminescence, but during this increment, MgO acted as activator (co-dopant) for Cu ions. This enhancement may contribute to the energy transfer from Mg2+ ions to monovalent Cu+ ion. The current results are discussed and compared with other related studies.

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

2012-07-01

184

Erbium-doped potassium bismuth gallate glasses  

NASA Astrophysics Data System (ADS)

We demonstrate potassium bismuth gallate glasses as suitable hosts for rare-earth-ion erbium (Er3+) operating in the 1.55-mum-wavelength region. The absorption and luminescence spectra along with the luminescence decay time were measured. The emission peak of the 4I13/2[right arrow]4I15/2 transition is at the 1.53-mum wavelength, and the spectral bandwidth is 85 nm, which is one of the broadest. The lifetime of the 4I13/2 level is approx2.42 ms, and the quantum efficiency is approx100%. The emission cross section is estimated to be approx12.4 x10-21 cm2, which is one of the highest among different oxide glasses. The gain coefficient is also calculated, and our results show that potassium bismuth gallate glasses are excellent host materials for broadband-amplifier and high-power-laser applications.

Man, S. Q.; Wong, S. F.; Pun, E. Y. B.

2002-08-01

185

Helium diffusion in curium-doped borosilicate waste glass  

NASA Astrophysics Data System (ADS)

The isothermal release of helium from 244Cm-doped borosilicate glass has been studied as a function of time at different annealing temperatures. Helium measurements were performed using a micro gas chromatograph coupled to a furnace installed in a hot cell at ATALANTE nuclear research facility. Plane-parallel glass samples were prepared from glass discs that had been stored for 5.1 years at room temperature, accumulating around 1019 alpha decays per gram of glass, a level that will be reached in current nuclear glass packages several thousand years after disposal.The experimental helium release data were simulated using a 3D numerical model to determine the helium diffusion coefficients. The extracted diffusion coefficients follow the Arrhenius law with an activation energy of 0.61 ± 0.03 eV and a pre-exponential factor of (5.7 ± 1.6) × 10-3 cm2 s-1. The results were compared with literature data on damaged and undamaged glasses to assess the effect of glass damage on helium release. The helium release results are consistent with a thermal diffusion mechanism involving only one population of helium atoms. The helium diffusion coefficients were unaffected by the glass alpha damage.

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

2011-09-01

186

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

187

Line patterning of (Sr,Ba)Nb2O6 crystals in borate glasses by transition metal atom heat processing  

NASA Astrophysics Data System (ADS)

Some NiO-doped Bi2O3,La2O3 SrO BaO Nb2O5 B2O3 glasses giving the formation of strontium barium niobate Sr0.5Ba0.5Nb2O6 (SBN) crystals with a tetragonal tungsten bronze structure through conventional crystallization in an electric furnace have been developed, and SBN crystal lines have been patterned on the glass surface by heat-assisted (250 300 °C) laser irradiation and scanning of continuous-wave Nd:YAG laser (wavelength: 1064 nm). The surface morphology and the quality of SBN crystal lines are examined from measurements of confocal scanning laser micrographs and polarized micro-Raman scattering spectra. The surface morphology of SBN crystal lines changes from periodic bump structures to homogeneous structures, depending on laser scanning conditions. It is suggested that the line patterned at the laser irradiation condition of laser power P=1 W and of laser scanning speed S=1 ?m/s in 2NiO 4La2O3 16SrO 16BaO 32Nb2O5 30B2O3 glass has a possibility of the orientation of SBN crystals along the laser scanning direction. The present study demonstrates that the transition metal atom heat processing (i.e., a combination of cw Nd:YAG laser and Ni2+ ions) is a novel technique for spatially selected crystallization of SBN crystals in glass.

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

2007-09-01

188

Irradiation effect on the acoustical properties of zinc lead borate glasses  

Microsoft Academic Search

The effect of -irradiation on the acoustical properties of xZnO.2xPbO.(1-3x)B2O3 glasses has been studied. Ultrasonic velocity and attenuation measurements have been made before and after -irradiation at room temperature in the frequency range 2.25-10 MHz. From the measured density and ultrasonic velocity data, the elastic moduli, Poisson's ratio and other parameters have been obtained. Changes in the acoustical properties are

G. Sharma; K. Singh; Manupriya; H. S. Klare; V. Rajendran; A. V. Gayathri Devi; S. B. Narang

2005-01-01

189

Upconversion in erbium-doped transparent glass ceramics  

NASA Astrophysics Data System (ADS)

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

Jones, Gina Christine

190

Stark level analysis for Er 3+-doped ZBLAN glass  

Microsoft Academic Search

From the absorption and emission spectra recorded in a conventional way at 13 K, the Stark levels in manifolds from 4I15\\/2 to 2H9\\/2 for Er3+-doped ZBLAN (ZrF4–BaF2–LaF3–AlF3–NaF) glass have been investigated by means of the effective crystal field model previously proposed to describe the average of local symmetries occupied by rare earth ions in oxide glasses [1]. This model, based

Y. D. Huang; M. Mortier; F. Auzel

2001-01-01

191

Energy upconversion in holmium doped lead-germano-tellurite glass  

NASA Astrophysics Data System (ADS)

Holmium doped lead-germano-tellurite glass was prepared by the melt quenching technique. The Judd-Ofelt intensity parameters were estimated as ?2=7.6×10-20, ?4=12.9×10-20, and ?6=2.5×10-20 cm2. Radiative transition probabilities and lifetimes were also determined for some of the levels. Room temperature upconversion emissions have been observed from Ho3+ at 497 nm under 532 nm laser excitation, and at 557 and 668 nm under 762 nm laser excitation. The upconversion emission mechanisms were found to be due to a step wise excitation process. Upconversion emission intensity enhanced in a heat treated glass.

Kamma, Indumathi; Reddy, B. Rami

2010-06-01

192

Luminescence and scintillation of Ce3+-doped high silica glass  

NASA Astrophysics Data System (ADS)

Ce3+-doped high silica glass was prepared by impregnation of Ce ions into a porous silica glass followed by high temperature sintering in a CO reducing atmosphere. The characteristic emission of Ce3+ 5d ? 4f transition peaking around 375 nm is observed in its luminescence spectra under UV and X-ray excitation. Its photoluminescence decay is governed by several tens of nanoseconds decay time. Its integral scintillation efficiency is comparable to that of a Bi4Ge3O12 (BGO) crystal under X-ray excitation. Scintillation light yield under gamma and alpha excitation was measured and compared with that of BGO.

Chewpraditkul, Weerapong; Shen, Yinglong; Chen, Danping; Yu, Bingkun; Prusa, Petr; Nikl, Martin; Beitlerova, Alena; Wanarak, Chalerm

2012-09-01

193

Light-controlled beam deflector in semiconductor doped glasses  

Microsoft Academic Search

We report on the operation of an all-optical beam deflector whereby the deflected signal beam can be more powerful than the driving beam. Therefore, we have transferred the modulation of the driving beam to the signal beam with power gain and angular deflection rate of 10 mrad\\/kW. The main component of our deflector is a sample of Cd(S,Se) doped glass

H. Ma; Cid B. de Araújo

1993-01-01

194

Scintillating luminescence of cerium-doped dense oxide glass  

Microsoft Academic Search

New dense oxide glass scintillator has been discovered in the system: B2O3-SiO2-Al2O3- Gd2O3 doped with trivalence cerium. This scintillator has a unique combination of properties including high scintillating light output, high density and desirable emission wavelength, large radiation hardness, short radiation length, and easy to produce in large size and low price. Here we compare the properties with those of

Chun Jiang; Junzhou Zhang; Fu-Xi Gan

1999-01-01

195

Glass nanocomposite of strontium bismuth niobate and lithium borate: structural and dielectric investigations  

Microsoft Academic Search

Glass nanocomposites (GNC) in the system (100?x)Li2B4O7?xSrBi2Nb2O9 (0?x?30) were prepared by splat quenching technique. The as-quenched samples of all the compositions under study have been confirmed to be amorphous by X-ray powder diffraction (XRD) studies. Differential thermal analyses (DTA) suggest the glassy nature of the as-quenched samples. High-resolution transmission electron microscopic (HRTEM) studies carried out on heat-treated samples reveal the

N Syam Prasad; G. N Subbanna; K. B. R Varma

2001-01-01

196

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

PubMed

The low-temperature states of bosonic fluids exhibit fundamental quantum effects at the macroscopic scale: the best-known examples are Bose-Einstein condensation and superfluidity, which have been tested experimentally in a variety of different systems. When bosons interact, disorder can destroy condensation, leading to a 'Bose glass'. This phase has been very elusive in experiments owing to the absence of any broken symmetry and to the simultaneous absence of a finite energy gap in the spectrum. Here we report the observation of a Bose glass of field-induced magnetic quasiparticles in a doped quantum magnet (bromine-doped dichloro-tetrakis-thiourea-nickel, DTN). The physics of DTN in a magnetic field is equivalent to that of a lattice gas of bosons in the grand canonical ensemble; bromine doping introduces disorder into the hopping and interaction strength of the bosons, leading to their localization into a Bose glass down to zero field, where it becomes an incompressible Mott glass. The transition from the Bose glass (corresponding to a gapless spin liquid) to the Bose-Einstein condensate (corresponding to a magnetically ordered phase) is marked by a universal exponent that governs the scaling of the critical temperature with the applied field, in excellent agreement with theoretical predictions. Our study represents a quantitative experimental account of the universal features of disordered bosons in the grand canonical ensemble. PMID:22996552

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

2012-09-20

197

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

PubMed

(100-x) mol % B(2)O(3) x mol % Me(2)O (Me = Li,Na,K) glasses, exposed to gamma-(60)Co irradiation to produce paramagnetic states, were characterized by W-band (95 GHz) pulse electron-nuclear double resonance (ENDOR) spectroscopy in order to characterize local structures occurring in the range of compositions between x=16 and x=25 at which the "boron oxide" anomaly occurs. The high resolution of nuclear frequencies allowed resolving the (7)Li and (11)B ENDOR lines. In the samples with x=16 and x=20 glasses, (11)B hyperfine couplings of 16, 24, and 36 MHz were observed and attributed to the tetraborate, triborate, and boron oxygen hole center (BOHC) structures, respectively. The x=25 samples showed hyperfine couplings of 15 MHz for the tetraborate and 36 MHz for BOHC. Density functional theory (DFT) calculations predicted for these structures negative hyperfine couplings, which were confirmed by W-band ENDOR. This suggests that a spin polarization mechanism accounts for the negative hyperfine structure splitting. PMID:19045204

Kordas, George; Goldfarb, Daniella

2008-10-21

198

Electron Spin Resonance and optical absorption spectroscopic studies of manganese centers in aluminium lead borate glasses.  

PubMed

Electron Spin Resonance (ESR) and optical absorption studies of 5Al(2)O(3)+75H(3)BO(3)+(20-x)PbO+xMnSO(4) (where x=0.5, 1,1.5 and 2 mol% of MnSO(4)) glasses at room temperature have been studied. The ESR spectrum of all the glasses exhibits resonance signals with effective isotropic g values at ?2.0, 3.3 and 4.3. The ESR resonance signal at isotropic g?2.0 has been attributed to Mn(2+) centers in an octahedral symmetry. The ESR resonance signals at isotropic g?3.3 and 4.3 have been attributed to the rhombic symmetry of the Mn(2+) ions. The zero-field splitting parameter (zfs) has been calculated from the intensities of the allowed hyperfine lines. The optical absorption spectrum exhibits an intense band in the visible region and it has been attributed to (5)E(g)?(5)T(2g) transition of Mn(3+)centers in an octahedral environment. The optical band gap and the Urbach energies have been calculated from the ultraviolet absorption edges. PMID:23000927

SivaRamaiah, G; LakshmanaRao, J

2012-08-19

199

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

PubMed

All glass leakage channel fibers have been demonstrated to be a potential practical solution for power scaling in fiber lasers beyond the nonlinear limits in conventional large mode area fibers. The all glass nature with absence of any air holes is especially useful for allowing the fibers to be used and fabricated much like conventional fibers. Previously, double clad active all glass leakage channel fibers used low index polymer as a pump guide with the drawbacks of being less reliable at high pump powers and not being able to change fiber outer diameter independent of pump guide dimension. In this work, we demonstrate, for the first time, ytterbium-doped double clad all glass leakage channel fibers with highly fluorine-doped silica as pump cladding. The new all glass leakage channel fibers have no polymer in the pump path and have independent control of fiber outer diameters and pump cladding dimension, and, therefore, enable designs with smaller pump guide for high pump absorption and, at the same time, with large fiber diameters to minimize micro and macro bending effects, a much desired features for large core fibers where intermodal coupling can be an issue due to a much increased mode density. An ytterbium-doped double clad PM fiber with core diameter of 80 microm is also reported, which can be coiled in 76 cm diameter coils. PMID:19466146

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

2009-05-25

200

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

SciTech Connect

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

Hudgens, J.J.; Martin, S.W. [Department of Materials Science and Engineering, Iowa State University of Science and Technology, Ames, Iowa 50011 (United States)

1996-03-01

201

Influence of Ce 3+ doping on the structure and luminescence of Er 3+-doped transparent glass-ceramics  

Microsoft Academic Search

Transparent glass-ceramics possess high thermal and mechanical properties, easy shaping allowing fibers elaboration and easy synthesis. However, previously studied Yb:Er-doped glass-ceramics do not appear efficient enough for optical amplification at 1.5?m in the telecommunication window. So, the addition of Ce3+ doping ions was performed.Oxyfluoride glasses (GeO2–PbO–PbF2) doped with ErF3, YbF3 and CeF3 were prepared and heated above glass transition temperature

G. Dantelle; M. Mortier; D. Vivien; G. Patriarche

2006-01-01

202

Scintillating glass doped with organic activator p-TP and/or POPOP  

NASA Astrophysics Data System (ADS)

Two organic activators, p-TP(p-terphenyl) and POPOP (1,4-bis(5-phenyloxazol-2-yl) benzene), which are normally used to prepare the scintillating plastic, were doped in tin fluorephosphate glasses to develop a serial of scintillating glasses with different concentrations. The fluorescence spectra and the transmission spectra of some scintillating glass were explored and the actual concentration organic in scintillating glass was estimated by comparing the extracted solution from glass with standard solution. Results show that the organic materials can be doped into inorganic glass, however, the actual concentration of organics doped in the glass is very low. Compared with scintillating plastic, the emission peak of scintillating glasses move towards the longer wavelength and POPOP is not wavelength shift any more. Keywords: Scintillating glass, doping, organic activator, concentration

Zhu, Dogmei; Luo, Fa; Zhao, Hongsheng; Zhou, Wancheng

2006-01-01

203

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

204

AC Conductivity Studies in Lithium-Borate Glass Containing Gold Nanoparticles  

NASA Astrophysics Data System (ADS)

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

Shivaprakash, Y.; Anavekar, R. V.

2011-07-01

205

LaSr-manganate powders by crystallization of a borate glass  

NASA Astrophysics Data System (ADS)

(LaSr)MnO3 powders with perovskite structure were prepared in the basic system MnO2-SrO-La2O3- B2O3 for the first time by a modified glass crystallization method. The annealing temperature was changed between 600 and 950°C. X-ray diffraction, magnetic measurements, ESMA and particle size investigations (specific surface) were carried out. The influence of the annealing conditions on the phase composition, the cation contents and the magnetic properties of the powders is discussed. Powder samples prepared under optimized conditions show values of specific saturation magnetization between 48 and 53Am2/kg, a Curie temperature between 369 and 389K and specific surfaces of about 10m2/g corresponding to a mean particle size of 100nm. The powders reveal the magneto-resistive effect.

Müller, R.; Schüppel, W.; Eick, T.; Steinmetz, H.; Steinbeiß, E.

2000-07-01

206

Dy3+-doped zinc fluorophosphate glasses for white luminescence applications  

NASA Astrophysics Data System (ADS)

Dysprosium (Dy3+) ions doped zinc fluorophosphate (PKAZLFDy: P2O5-K2O-Al2O3-ZnF2-LiF-Dy2O3) glasses have been prepared and investigated their spectroscopic properties using absorption, emission and decay measurements. Judd-Ofelt analysis has been carried out to obtain the intensity parameters and in turn predicted radiative properties for the 4F9/2 level of 1.0 mol% of Dy2O3 doped glass. Visible luminescence spectra have been obtained due to 4F9/2 ? 6HJ (J = 11/2, 13/2, 15/2) transitions of Dy3+ ions under 385 nm excitation. The yellow-to-blue luminescence intensity ratios and chromaticity coordinates of Dy3+ ions in these glasses have been analyzed as a function of Dy3+ ion concentration. The decay profiles for the 4F9/2 level exhibit perfectly single exponential at lower concentrations (up to 1.0 mol%) and turn into non-exponential for higher concentrations (>1.0 mol%) due to energy transfer between donor (excited state Dy3+ ion) and acceptor (ground state Dy3+ ion). The results reveal that these glasses emit bright white light which is suitable for the development of W-LEDs.

Vijaya, N.; Upendra Kumar, K.; Jayasankar, C. K.

2013-09-01

207

XRD and IR Studies of Yb3+ Doped Tellurite Glass  

NASA Astrophysics Data System (ADS)

Ytterbium doped sodium-tellurite glasses having composition of (80-x) TeO2-20Na2O-(x)Yb2O3 (where x = 0.0-2.0 mol%) are prepared by melt quenching technique. The crystallinity of the glass has been examined using X-ray diffraction technique. All glass are found to be amorphous in nature. Meanwhile the transmission spectroscopy is determine by using Infrared Spectroscopy. It is found that the absorption vibrational spectra occurs at range 3405-3423 cm-1, 1632-1643 cm-1, 1377-1382 cm-1, 721-732 cm-1 and 589-606 cm-1 peaks. The predominant peaks around 700 cm-1 is due to the Te-O-Te vibration while peak at 600 cm-1 is due to the vibration of Yb3+ ions.

Sahar, M. R.; Isa, H. Noor

2011-03-01

208

High upconversion optical gain of Er3+-doped tellurite glass  

NASA Astrophysics Data System (ADS)

The upconversion technique of rare-earth-doped glasses or crystals is a potential route for achieving short-wavelength lasers (SWLs). The optical gain is an important parameter for evaluating lasing medium performance. Therefore, upconversion luminescence in glass with composition of 70TeO2-9PbF2-10AlF3-10BaF2-1Er2O3 was demonstrated, and the small-signal optical gain was measured via an amplified spontaneous emission technique when the sample was excited with a 980 nm laser. It was found that the optical gain was as large as 4.0 dB/cm, thus indicating that this glass may be a good medium for SWLs.

Fu, S. B.; Chen, B. J.; Zhang, J. S.; Li, X. P.; Zhong, H.; Tian, B. N.; Wang, Y. Z.; Sun, M.; Zhang, X. Q.; Cheng, L. H.; Zhong, H. Y.; Xia, H. P.

2013-10-01

209

Optical characteristics of silver-doped polarizing glass  

NASA Astrophysics Data System (ADS)

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.

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

2002-06-01

210

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

211

Effect of cerium on luminescence and irradiation resistance of Tb 3+ doped silicate glasses  

Microsoft Academic Search

The effect of cerium addition on luminescence and irradiation resistance of Tb3+ doped silicate glasses was investigated. Results showed that Tb3+ doped silicate glasses mainly emit weak blue (400–460nm) and strong green (480–570nm) fluorescences. Cerium addition has a significant effect on the luminescence of Tb3+ doped silicate glasses. Both the luminescent intensity at 550nm and the afterglow life quickly decreases

C. K. Zu; J. Chen; H. F. Zhao; B. Han; Y. H. Liu; Y. H. Wang

2009-01-01

212

Synthesis and characterization of low-melting scintillating glass doped with organic activator  

NASA Astrophysics Data System (ADS)

New colliders for high-energy physics studies require scintillators with short decay time, high density, good radiation hardness and low cost. It is possible to make glass scintillators that can meet these requirements by doping organic scintillating activators into an inorganic glass host. In this research, p-Terphenyl as the activator is doped into lead-tin-fluorophosphate glasses. There is no detectable change of the dopant on the densities and characteristic temperatures of the glass host. The hybrid scintillating glasses doped with p-TP possess 5 ns decay time and a broad fluorescence emission band, the peak of which is at about 545 nm. Although the light yields of the glasses are low, this research shows that it is possible to develop good hybrid scintillating glasses by doping organic activators into inorganic glass host.

Zhao, H.; Zhou, W.; Zhu, D.; Wu, J.

2000-07-01

213

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

Microsoft Academic Search

A glass belonging to the system SiO2–Al2O3–CaO–Na2O has been subjected to a patented ion-exchange treatment to induce surface antibacterial activity by doping with silver ions.\\u000a Doped samples have been characterized by means of X-Ray diffraction (XRD), scanning electron microscopy (SEM) observation,\\u000a energy dispersion spectrometry (EDS) analysis, in vitro bioactivity test, Ag+ leaching test by graphite furnace atomic absorption spectroscopy (GFAAS) analyses,

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

2009-01-01

214

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

PubMed

In Part I, the in vitro degradation of bioactivAR52115e glass scaffolds with a microstructure similar to that of human trabecular bone, but with three different compositions, was investigated as a function of immersion time in a simulated body fluid. The glasses consisted of a silicate (13-93) composition, a borosilicate composition (designated 13-93B1), and a borate composition (13-93B3), in which one-third or all of the SiO2 content of 13-93 was replaced by B2O3, respectively. This work is an extension of Part I, to investigate the effect of the glass composition on the in vitro response of osteogenic MLO-A5 cells to these scaffolds, and on the ability of the scaffolds to support tissue infiltration in a rat subcutaneous implantation model. The results of assays for cell viability and alkaline phosphatase activity showed that the slower degrading silicate 13-93 and borosilicate 13-93B1 scaffolds were far better than the borate 13-93B3 scaffolds in supporting cell proliferation and function. However, all three groups of scaffolds showed the ability to support tissue infiltration in vivo after implantation for 6 weeks. The results indicate that the required bioactivity and degradation rate may be achieved by substituting an appropriate amount of SiO2 in 13-93 glass with B2O3, and that these trabecular glass scaffolds could serve as substrates for the repair and regeneration of contained bone defects. PMID:20540099

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

2010-10-01

215

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

216

The role of V2O5 in the modification of structural, optical and electrical properties of vanadium barium borate glasses  

NASA Astrophysics Data System (ADS)

Vanadium barium borate glasses were prepared by a normal melt quench technique. The infrared spectra of these V2O5·BaO·B2O3 glasses were recorded over a continuous spectral range (400 4000 cm-1) in an attempt to study their structure systematically. The conversion from three- to four-fold coordinated boron took place. The fundamental absorption edge for all the glasses was analyzed in terms of the theory proposed by Davis and Mott. The position of the absorption edge and hence the value of the optical band gap was found to depend on the semiconducting glass composition. The absorption in these glasses is believed to be associated with indirect transitions. The origin of the Urbach energy is associated with phonon-assisted indirect transitions. The theoretical optical basicity has been calculated and is correlated with a change in the optical band gap. The variation in density and molar volume with composition has been investigated in terms of the structural modifications that take place in the glass matrix on addition of V2O5. The DC electrical conductivity as function of the V2O5:BaO and the V2O5:B2O3 ratio has been measured. The change in conductivity and activation energy with composition indicates that the conduction process varies from ionic to polaronic.

Sindhu, S.; Sanghi, S.; Agarwal, A.; Sonam; Seth, V. P.; Kishore, N.

2005-08-01

217

Glass composition dependence of Eu3+ polarization in oxide glasses  

Microsoft Academic Search

Eu3+-doped borate, silicate, and phosphate glasses were prepared by the melt-quenching method. Eu LIII-edge X-ray absorption spectra were measured to study the polarization of the Eu3+ ions in the glasses. The EXAFS analysis reveals that the nearest oxygen coordination number of the Eu3+ ions is 6, but the actual coordination number of Eu3+ ions is more than 6 with the

Noriyuki Wada; Kazuo Kojima; Kazuhiko Ozutsumi

218

Photon avalanche up-conversion in holmium doped fluoride glasses  

SciTech Connect

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

Chen, Y.H.; Liu, G.K.; Beitz, J.V. [Argonne National Lab., IL (United States). Chemistry Division; Jie Wang [Shanghai Institute of Optics and Fine Mechanics, Shanghai (China)

1996-08-01

219

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

2008-11-06

220

Er3+-doped tellurofluorophosphate glasses for lasers and optical amplifiers  

Microsoft Academic Search

Absorption, fluorescence and decay properties of erbium-doped alkali tellurofluorophosphate glasses (RTFP) with the molar compositions of 50 (NaPO3)6-10 TeO2-20 AlF3-19 RF-1 Er2O3 (R = Li,Na or K) have been investigated in order to utilize these materials for the development of fibre amplifiers and lasers. The Judd-Ofelt (JO) model was applied to the absorption intensities of Er3+ (4f11) transitions to determine

M. Jayasimhadri; L. R. Moorthy; K. Kojima; K. Yamamoto; Noriko Wada; Noriyuki Wada

2005-01-01

221

Energy upconversion in holmium doped lead-germano-tellurite glass  

SciTech Connect

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

Kamma, Indumathi; Reddy, B. Rami [Department of Physics, Alabama A and M University, P.O. Box 1268, Normal, Alabama 35762 (United States)

2010-06-15

222

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

223

Development of continuous glass melting for production of Nd-doped phosphate glasses for the NIF and LMJ laser systems  

NASA Astrophysics Data System (ADS)

The NIF and LMJ laser systems require about 3380 and 4752 Nd-doped laser glass slabs, respectively. Continuous laser glass melting and forming will be used for the first time to manufacture these slabs. Two vendors have been chosen to produce the glass: Hoya Corporation and Schott Glass Technologies. The laser glass melting systems that each of these two vendors have designed, built and tested are arguably the most advanced in the world. Production of the laser glass will begin on a pilot scale in the fall of 1998.

Campbell, John H.; McLean, M. J.; Hawley-Fedder, R.; Suratwala, Tayyab I.; Ficini-Dorn, G.; Trombert, Jean-Hugues

1999-07-01

224

Spectroscopic properties of Er doped and Er, Nd codoped fluoride glasses under simulated sunlight illumination  

Microsoft Academic Search

We investigated the fluorescence characteristics of Er codoped Nd doped ZBLAN glasses proposed for solar pumped fiber laser (SPFL) under simulated sunlight. Er is used as a sensitizer because it absorbs a part of the ultraviolet and visible light where is no absorption of Nd. Under simulated sunlight illumination, Er singly doped fluoride glass displayed four emission bands with peaks

Shintaro Mizuno; Hiroshi Ito; Kazuo Hasegawa; Hiroyuki Kawai; Hiroyuki Nasu; Mark A. Hughes; Takenobu Suzuki; Yasutake Ohishi

2011-01-01

225

Spectroscopic properties and laser emission of Tm doped ZBLAN glass at 1.8 ?m  

Microsoft Academic Search

A Tm doped ZBLAN glass is investigated to obtain a laser emission near 1.8 ?m instead of classical crystalline host materials. After a brief description of the basic optical properties of Tm doped ZBLAN glass, demonstration of an efficient laser emission in the bulk material is presented. The other investigations are focussed on its wavelength tunability, its tolerance versus the

J. L. Doualan; S. Girard; H. Haquin; J. L. Adam; J. Montagne

2003-01-01

226

Annular polishing of large-aperture Nd-doped metaphosphate glasses  

NASA Astrophysics Data System (ADS)

Large-aperture Nd-doped metaphosphate glasses are used in high-power/high-energy laser facilities. High transmission wave front accuracy of Nd-doped metaphosphate glasses is required to decrease beam distortion, which affects the focus ability and damages optical components. Elliptical shape astigmatism of the transmission wave front easily occurs when Nd-doped metaphosphate glasses are detected and utilized at Brewster incident angle compared with zero angle. The astigmatism is difficult to decrease for precision annular polishing because the surface profile adjustment of the polishing pitch plane has low accuracy. Non-uniform removal at different velocity rates between the pitch plane and Nd-doped metaphosphate glasses can be used to eliminate horizontal elliptical-shaped astigmatism. The improved process contributes to the production of high-efficiency Nd-doped metaphosphate glasses.

Shan, Haiyang; Xu, Xueke; He, Hongbo; Wu, Fulin; Yi, Kui; Shao, Jianda

2013-07-01

227

Concentration dependence of the fluorescence decay profile in transition metal doped chalcogenide glass  

Microsoft Academic Search

In this paper we present the fluorescence decay profiles of vanadium and titanium doped gallium lanthanum sulphide (GLS) glass at various doping concentrations between 0.01 and 1% (molar). We demonstrate that below a critical doping concentration the fluorescence decay profile can be fitted with the stretched exponential function: exp(-(t\\/?) ? ), where ? is the fluorescence lifetime and ? is

M. Hughes; D. W. Hewak; R. J. Curry

228

Nd2O3 doped low silica calcium aluminosilicate glasses: Thermomechanical properties  

Microsoft Academic Search

The effects of Nd2O3 doping on the thermal and mechanical properties of vacuum melted, low silica, calcium aluminosilicate glasses are presented. For the doped glasses, the vitrification limit was found to correspond to a maximum load of 5 wt % Nd2O3. The influence of the rare earth doping on the thermal diffusivity, thermal conductivity, and Vickers hardness was such that

M. L. Baesso; A. C. Bento; A. R. Duarte; A. M. Neto; L. C. M. Miranda; J. A. Sampaio; T. Catunda; S. Gama; F. C. G. Gandra

1999-01-01

229

Cerium doped soda-lime-silicate glasses: effects of silver ion-exchange on optical properties  

Microsoft Academic Search

Effects of silver ion-exchange on optical absorption (OA) and photoluminescence (PL) spectra of a cerium doped soda-lime-silicate glass at room temperature are investigated. The optical spectra are described in terms of the characteristic transitions 4f?5d originated in Ce3+ ions placed mainly in two different sites of the glass network. As Ag+ ions are introduced into the cerium doped glass, they

S. E Paje; M. A Garc??a; M. A Villegas; J Llopis

2001-01-01

230

Sol-gel preparation and phosphorescence property of Mn 2+ -doped zinc borosilicate glass thin films  

Microsoft Academic Search

Mn2+-doped zinc borosilicate (ZBSM) glass thin films were first synthesized by sol-gel method. In the experiment, a thin gel film\\u000a was deposited onto quartz glass substrates by dip-coating method and then heat-treated to form a Mn2+-doped zinc borosilicate glass thin film. Long lasting phosphorescence (LLP) and photo-stimulated long lasting phosphorescence\\u000a (PSLLP) were found in the film sample. According to fluorescence

Fengfeng Li; Mingxi Zhang; Guiqin Hou; Yi Shen; Zhigang Liu; Hongsheng Li

2011-01-01

231

Thermomechanical and optical properties of calcium aluminosilicate glasses doped with Er 3+ and Yb 3+  

Microsoft Academic Search

In this work a series of Er2O3 and Yb2O3 doped and Er2O3–Yb2O3 co-doped low silica calcium aluminosilicate glasses have been melted at 1470°C under vacuum conditions. Measurements of optical absorption coefficient, mass density, refractive index, Vickers micro-hardness, glass transformation temperature (Tg) and crystallization temperature (Tx) have been carried out. The results showed that these glasses dissolved ?1.5 mol% Er2O3 and

J. A Sampaio; T Catunda; A. A Coelho; S Gama; A. C Bento; L. C. M Miranda; M. L Baesso

2000-01-01

232

Spectroscopic characteristics of Sm3+-doped alkali fluorophosphate glasses.  

PubMed

Optical absorption, luminescence and lifetime measurements of Sm(3+)-doped alkali fluorophosphate glasses with molar compositions of 50(NaPO(3))(6)+10TeO(2)+20AlF(3)+19RF+1Sm(2)O(3) (R=Li, Na and K) are described. The variation of optical properties with glass composition plays a dominant role in the determination of efficient laser materials. From the experimental oscillator strengths of f-f electric dipole transitions, the phenomenological Judd-Ofelt parameters have been evaluated and are used to evaluate radiative parameters such as radiative transition probabilities (A(R)), branching ratios (beta(R)), lifetimes (tau(R)) and integrated absorption cross-section (sigma(a)) for various excited levels. The predicted values of tau(R) and beta(R) from the (4)G(5/2) excited level to its lower levels are compared with the experimentally measured values. Stimulated emission cross-sections (sigma(e)) were also determined for (4)G(5/2)-->(6)H(J) (J=5/2, 7/2, 9/2 and 11/2) emission transitions. From the emission transitions of Sm(3+) in these alkali tellurofluorophosphate glasses certain potential laser transitions have been identified. PMID:16530469

Jayasimhadri, M; Moorthy, L R; Saleem, S A; Ravikumar, R V S S N

2006-03-10

233

Combinatorial fluorescence lifetime measuring system for developing Er-doped transparent glass ceramics  

Microsoft Academic Search

Fluorescence lifetime of Er3+ was measured for F-doped tellurite glasses with parallel heat treatment under a temperature gradient atmosphere in order to find the annealing condition to make transparent glass ceramics in which Er3+ ions are located in the precipitated crystals. The preparation and annealing of the samples were performed in a vertical temperature gradient furnace, where molten glass was

S. Todoroki; S. Inoue

2004-01-01

234

Broad-Spectrum Bactericidal Activity of Ag2O-Doped Bioactive Glass  

Microsoft Academic Search

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

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

2002-01-01

235

Novel rare earth doped tellurite glasses for fiber lasers in the 2-micron wavelength region  

NASA Astrophysics Data System (ADS)

In this paper Tm-doped tellurite glasses (75TeO2-20ZnO-5 Na2O, mol%) were prepared and characterized, and codoping with Yb was investigated in order to improve pump efficiency and wavelength emission range. Emission spectra and lifetime measurements were obtained by pumping Tm-doped tellurite glasses at 800 nm and Yb-Tm co-doped tellurite glasses at 980 nm, thus exploiting the Yb-Tm energy transfer mechanism. Highly Yb-doped Tm-tellurite glasses were investigated (Yb2O3 concentrations up to 5 wt%) and an increase in 3F4 lifetime with Yb2O3 concentrations higher than 3% was observed. This showed that high amounts of Yb do not affect lifetime of the metastable state, thus allowing investigation of lasers in this range of doping concentrations.

Milanese, Daniel; Vota, Monica; Liao, Guihua; Ferraris, Monica; Coluccelli, Nicola; Taccheo, Stefano

2007-03-01

236

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

PubMed

Bioactive glass scaffolds with a microstructure similar to that of dry human trabecular bone but with three different compositions were evaluated for potential applications in bone repair. The preparation of the scaffolds and the effect of the glass composition on the degradation and conversion of the scaffolds to a hydroxyapatite (HA)-type material in a simulated body fluid (SBF) are reported here (Part I). The in vitro response of osteogenic cells to the scaffolds and the in vivo evaluation of the scaffolds in a rat subcutaneous implantation model are described in Part II. Scaffolds (porosity = 78-82%; pore size = 100-500 microm) were prepared using a polymer foam replication technique. The glasses consisted of a silicate (13-93) composition, a borosilicate composition (designated 13-93B1), and a borate composition (13-93B3), in which one-third or all of the SiO2 content of 13-93 was replaced by B2O3, respectively. The conversion rate of the scaffolds to HA in the SBF increased markedly with the B2O3 content of the glass. Concurrently, the pH of the SBF also increased with the B2O3 content of the scaffolds. The compressive strengths of the as-prepared scaffolds (5-11 MPa) were in the upper range of values reported for trabecular bone, but they decreased markedly with immersion time in the SBF and with increasing B2O3 content of the glass. The results show that scaffolds with a wide range of bioactivity and degradation rate can be achieved by replacing varying amounts of SiO(2) in silicate bioactive glass with B2O3. PMID:20544804

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

2010-10-01

237

Local precipitation of upconversion nanocrystals in rare-earth-doped oxyfluoride glasses by laser irradiation  

NASA Astrophysics Data System (ADS)

Rare earth-doped oxyfluoride glass of the 50SiO2 -50PbF2 -5ErF3 composition in molar ratio was developed. When the oxyfluoride glass is heat-treated at the first cystallization temperature, the glass gives the glass-ceramic in which rare earth-containing fluorite-type nanocrystals of about 20 nm in diameter uniformly precipitate in the glass matrices. The glass-ceramic is trasnparent to the naked eye like no heat-treated oxyfluoride glass. The glass-ceramic exhibits highly efficient upconversion luminescence under 800 and/or 980 nm laser light excitation. On the other hand, the oxyfluoride glass can be locally changed to glass-ceramic in the forms of dot, line, plane, letter, etc. by thermal energies generated from light absorption of various lasers. In the case of CO2 laser irradiation the formation of such glass-ceramic occurs near the surface of glass. In the case of 800 or 980 nm irradiation by Ti:sapphire laser or laser diodes, on the other hand, the formation of such glass-ceramic occurs near the surface and/or inside of glass. The glass-ceramic parts can be easily read by upconversion luminescence under laser excitation. Therefore, the presently developed rare earth-doped oxyfluoride glass can be utilized as optical devices of the writing and reading memory, which can be utilized as specific devices for security information.

Hashima, Hidekazu; Konishi, Akio; Tanigami, Yoshinori; Shibata, Daisuke; Kawamoto, Yoji

2004-06-01

238

Enhanced frequency upconversion in Er3+-doped sodium lead tellurite glass containing silver nanoparticles  

NASA Astrophysics Data System (ADS)

A series of silver nanoparticle embedded in erbium-doped tellurite glasses were synthesized using a one step melt-quenching method. Density and refractive index of glasses were measured. Thermal and optical characterizations were performed and plasmon bands of elliptical nanoparticles were observed. An enhancement of green (525 and 550 nm) and red (632 nm) lines in luminescence spectra of Er3+-doped silver-embedded tellurite glass was recorded and explained by energy transfer mechanism from silver nanoparticles to erbium ion in addition to enhanced local field in vicinity of metallic nanoparticles in the glass. The presence of nanoparticles was confirmed by transmission electron microscopy imaging and reduction of silver ions to silver neutral particles discussed through the redox potential estimation in probable reactions. Silver-erbium co-doped tellurite glass exhibits strong novel optical properties which nominate it as the promising glass for laser, color displays, and photonic applications.

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

2012-09-01

239

Properties of a new average power Nd-doped phosphate laser 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 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.; Wilke, G.D. [Lawrence Livermore National Lab., CA (United States); Hayden, J.S. [Schott Glass Technologies, Duryea, PA (United States)

1995-03-09

240

Influence of CeO2 addition on the electrical and optical properties of lithium borate glasses  

NASA Astrophysics Data System (ADS)

The glass series with general formula 15 Li2O-(85-X) B2O3-X CeO2 was prepared using the conventional melt quench technique. The electrical conductivity, the optical properties and the coefficient of thermal expansion were measured for the prepared glasses. The conductivity of the glasses decreases with the addition of CeO2 because the mobility of Li+ ions and the compactness of the glass structure decrease. The density and the refractive index of the glasses increase, whereas the optical band gap and the radiation length decrease because of the structural changes.

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

2013-10-01

241

Photoinduced second-harmonic generation in titanium and cerium-doped lead silicate glasses  

Microsoft Academic Search

Photoinduced second harmonic generation in titanium and cerium doped lead-silicate glasses at different infrared preparation intensities is reported. The influence of dopants on second harmonic conversion efficiency is discussed.

Evgeni M. Dianov; Dmitry S. Starodubov; Leonid B. Glebov; A. I. Ignat'ev; Nikolai V. Nikonorov; Ildar F. Salahetdinov

1996-01-01

242

Photoinduced second-harmonic generation in titanium and cerium-doped lead silicate glasses  

NASA Astrophysics Data System (ADS)

Photoinduced second harmonic generation in titanium and cerium doped lead-silicate glasses at different infrared preparation intensities is reported. The influence of dopants on second harmonic conversion efficiency is discussed.

Dianov, Evgeni M.; Starodubov, Dmitry S.; Glebov, Leonid B.; Ignat'ev, A. I.; Nikonorov, Nikolai V.; Salahetdinov, Ildar F.

1996-05-01

243

Luminescence of Yb2+, Yb3+ co-doped silica glass for white light source  

NASA Astrophysics Data System (ADS)

Yb2+, Yb3+ co-doped silica glasses were prepared by solid state reaction under vacuum condition for the first time. The luminescence properties of Yb2+-doped silica glass were investigated. There are four strong absorption bands in the Ultraviolet (UV) light region due to the 4f14-4f135d1 transition of the Yb2+ ions. The main emission wavelength of the Yb2+-doped silica glass was around 530 nm by the excited wavelength of 398 nm. The full width at half maximum (FWHM) of the excitation and emission bands were 137 nm, 165 nm respectively. The results suggest the Yb2+-doped silica glasses may be the potential medium for white light sources based on near UV LED chip.

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

2012-03-01

244

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

245

Influence of annealing on optical properties of cerium doped soda-lime–silicate glasses  

Microsoft Academic Search

Effects of annealing on optical absorption (OA) and photoluminescence (PL), emission and excitation spectra from a cerium doped soda-lime–silicate glass ion-exchanged with silver were investigated. Annealing experiments were performed at temperatures of 350 and 400°C, far below the 569°C transition temperature measured for the doped glass. Evidence of surface-plasmon resonance of metallic silver nanoparticles and its subsequent disappearance in the

M. A Garc??a; J Llopis; M. A Villegas; S. E Paje

2001-01-01

246

Synthesis, Absorption Spectra, and Luminescence of Potassium Aluminosilicophosphate Glass Doped with Mn(II) Compounds  

Microsoft Academic Search

Recently the interest in spectroscopic and luminescence properties of inorganic glasses doped with 3d elements (Ti, Cr, V, Cu, etc.) increased. These materials are used as active components in quantum electronics, optoelectronics, and fiber optics [1 7]. In this work we prepared potassium aluminosilicophosphate glass doped with Mn(II) and studied the spectroscopic properties of Mn(II) in this system. The potassium

I. M. Batyaev; A. M. Tinus; S. M. Begel'dieva

2001-01-01

247

Electrical conduction and dielectric properties of vanadium phosphate glasses doped with lithium  

Microsoft Academic Search

AC conductivity and dielectric studies on vanadium phosphate glasses doped with lithium have been carried out in the frequency range 0.2–100kHz and temperature range 290–493K. The frequency dependence of the conductivity at higher frequencies in glasses obeys a power relationship, ?ac=A?s. The obtained values of the power s lie in the range 0.5?s?1 for both undoped and doped with low

F. E. Salman; N. Shash; H. Abou El-Haded; M. K. El-Mansy

2002-01-01

248

Broadband optical amplification near 1300 nm in bismuth-doped germanate glass  

NASA Astrophysics Data System (ADS)

In this paper, we present the broadband optical amplification in bismuth-doped germanate glass, at the second telecommunication window when excited with 808 nm and 980 nm laser diodes, respectively. The amplification range is from 1272 nm to 1348 nm wavelength, which is within the O-band of silica fiber communication. This bismuth-doped glass can be used as ultra broadband amplification material for wavelength-division-multiplexing (WDM) at the second telecommunication window.

Ren, J.; Wu, B.; Jiang, X.; Dong, H.; Zeng, H.; Qiu, J.

2007-08-01

249

Effects of CuO co-doping on ?-ray irradiation resistance of active ions doped phosphate glasses  

NASA Astrophysics Data System (ADS)

The effect of copper ion doping on the ?-ray irradiation resistance of Mn2+ and Pr3+ doped phosphate glasses has been studied. UV–visible transmission spectra and photoluminescence spectra have been measured before and after ?-irradiation to characterize the radiation-induced defects. The electron paramagnetic resonance spectra of the irradiated samples with, and without Cu ions have been compared to show the ability of Cu ions to suppress the generation of radiation-induced color centers. The differential transmission spectra and the radiation-induced absorption coefficients have also been calculated for discussion of the observed phenomena. The much improved ?-irradiation resistance of Mn2+ and Pr3+ doped phosphate glasses has been demonstrated through CuO co-doping.

Zhang, Zhihuan; Baccaro, Stefania; Cemmi, Alessia; Shen, Wei; Chen, Guorong

2013-09-01

250

Concentration dependence of the fluorescence decay profile in transition metal doped chalcogenide glass  

Microsoft Academic Search

In this paper we present the fluorescence decay profiles of vanadium and titanium doped gallium lanthanum sulphide (GLS) glass at various doping concentrations between 0.01 and 1% (molar). We demonstrate that below a critical doping concentration the fluorescence decay profile can be fitted with the stretched exponential function: exp[-(t\\/tau)beta], where tau is the fluorescence lifetime and beta is the stretch

M. Hughes; D. W. Hewak; R. J. Curry

2007-01-01

251

Cobalt-Doped Transparent Glass Ceramic as a Saturable Absorber Q Switch for Erbium:Glass Lasers  

Microsoft Academic Search

A new saturable absorber Q switch for 1.54- m Er:glass lasers is presented. The saturable absorber is a transparent glass ceramic that contains magnesium -aluminum spinel nanocrystallites doped with tetrahedrally coordinated Co2 +ions. We obtained Q -switched pulses of up to 5.5 mJ in energy and 80 ns in duration at 1.54 m. The relaxation time of 4A2 4T1 (4F

Alexander M. Malyarevich; Igor A. Denisov; Konstantin V. Yumashev; Olga S. Dymshits; Alexander A. Zhilin; Uk Kang

2001-01-01

252

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

253

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

NASA Astrophysics Data System (ADS)

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

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

2012-12-01

254

Ion-exchanged waveguides in glass doped with PbS quantum dots  

Microsoft Academic Search

The lowest-loss (<~1 dB\\/cm) ion-exchanged waveguides in glass doped with PbS quantum dots are presented. Near-field mode profile and refractive index profile using the refracted near-field technique were measured for these waveguides. We demonstrate that the optical properties of this glass remain unchanged during the ion-exchange process.

Jason M. Auxier; Michael M. Morrell; Brian R. West; Seppo Honkanen; Axel Schülzgen; Nasser Peyghambarian; Sabyasachi Sen; Nicholas F. Borrelli

2004-01-01

255

Raman spectra of soda-lime-silicate glass doped with rare earth  

NASA Astrophysics Data System (ADS)

Soda-lime-silicate glasses doped with different rare earth oxides (La 2 O 3 , CeO 2 , Nd 2 O 3 , Gd 2 O 3 and Y 2 O 3 ) of 1 mol% content were prepared by the traditional melting-quenching methods. In order to reveal the effects of rare earth elements on the behavior of soda-lime-silicate glass the structures of soda-lime-silicate glasses doped with different rare earth oxides were determined using an INVIA confocal microRaman spectrometer equipped with a CCD detector, and viscosities of glass melts were measured using a rotating crucible viscometer; the melting temperature of the studied glasses was derived on the basis of the Arrhenius equation. Three expressions of the fraction of non-bridging oxygen (NBO/NBO+BO), average number of non-bridging oxygen (NBO) per tetrahedron (NBO/tetrahedron) and average number of bridging corners per tetrahedron (bridges/tetrahedron) for investigated soda-lime-silicate glasses were given, and the effect of rare earth dopants on the structure of soda-lime-silicate was characterized by the Raman shift, variation of the [SiO 4 ] tetrahedron structural unit Q n ( n =1,2,3,4), fraction of non-bridging oxygen and the average number of bridging corners per tetrahedron. The effect of doping rare earth oxides into glass on the viscosity and melting temperature was interpreted by changes in structure of soda-lime-silicate glasses doped with rare earth oxides.

Wang, Mitang; Cheng, Jinshu; Li, Mei; He, Feng

2011-10-01

256

Optical and structural investigation on rare-earth-doped aluminophosphate glasses  

Microsoft Academic Search

Aluminophosphate glasses belonging to the oxide system Li2O–BaO–Al2O3–La2O3–P2O5, un-doped and doped with rare-earth metal ions (Ce4+, Nd3+, Sm3+) were obtained by a wet non-conventional method. The influence of the doping ions on the optical properties of the phosphate glasses has been investigated in relation with structural features of the vitreous matrix. The optical behavior has been studied by ultra-violet–visible–near-infra-red (UV–VIS–NIR)

M. Elisa; I. Cristina Vasiliu; Cristiana E. A. Grigorescu; Bogdan Grigoras; Horatiu Niciu; Daniela Niciu; Aurelia Meghea; Nicoleta Iftimie; Maria Giurginca; H. J. Trodahl; M. Dalley

2006-01-01

257

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

258

Scintillation luminescence of cerium-doped borosilicate glass containing rare-earth oxide  

NASA Astrophysics Data System (ADS)

The properties of high rare-earth-containing borosilicate glasses have been investigated to assess the potential for using these materials to construct electromagnetic calorimeters for particle physics. We report here on measurements of scintillation yield, transmission and decay time, on large blocks of Ce3+-doped Gd2O3-based glasses. The samples were excited by a high energy X-ray beam and the associated scintillation yield and decay time was measured. The optical transmission of the samples was measured. It was observed that scintillation yield of present scintillation glass is 20% of BGO scintillation yield, decay time is in range of 50 - 80 ns, glass density is 5.50 g/cm3. It was concluded that higher light yield and density make this glass become promising candidate for cerium doped dense glass scintillator.

Jiang, Chun; Zeng, Qingji; Gan, Fuxi

2000-11-01

259

Erbium doped tellurite glasses with improved thermal properties as promising candidates for laser action and amplification  

NASA Astrophysics Data System (ADS)

The influence of composition on the thermal stability of tellurite glasses was investigated by using differential scanning calorimetry (DSC). The studied glasses were synthesized by conventional melting quenching method. The best thermal stability and poor crystallization tendency were obtained for the glass composed of 65TeO2-15ZnO-10Na2O-5BaO-3La2O3 doped with Er2O3 (2 mol %). This glass will be referred, in this article, as TZNBL: Er3+ glass.

Benmadani, Y.; Kermaoui, A.; Chalal, M.; Khemici, W.; Kellou, A.; Pellé, F.

2013-10-01

260

Influence of CeO 2 on scintillating properties of Tb 3+-doped silicate glasses  

Microsoft Academic Search

A series of Tb3+-, Ce3+-doped, and Tb3+\\/Ce3+-codoped silicate glasses were synthesized by melt-quenching technique. Some properties of the investigated glasses were characterized by X-ray photoelectron spectroscopy (XPS), photoluminescence (PL), X-ray excited luminescence (XEL) and thermoluminescence (TL) spectra. The result of XPS revealed that both Ce3+ and Ce4+ ions coexisted in these silicate glasses, and energy transfer from Ce3+ to Tb3+

Xinyuan SUN; Mu GU; Min ZHANG; Shiming HUANG

2010-01-01

261

Crystallization and fluorescence properties of Nd 3+-doped transparent oxyfluoride glass ceramics  

Microsoft Academic Search

Nd3+-doped transparent oxyfluoride glass ceramics containing CaF2 were prepared through controlled crystallization of melt-quenched glass. X-ray diffraction (XRD) analysis and transmission electron microscopy (TEM) observation revealed the precipitation of CaF2 crystallites with about 13nm in size among the glass matrix after heat-treatment at 650°C for 2h. Non-isothermal investigation on CaF2 crystallization kinetics showed that the apparent activation energy Ea and

Daqin Chen; Yuansheng Wang; Yunlong Yu; Zhongjian Hu

2005-01-01

262

Application of CdSe-nanocrystallite-doped glass for temperature measurements in fiber sensors  

Microsoft Academic Search

A temperature fiber sensor based on CdSe-nanocrystallite- doped phosphate glass as a sensing element is reported. This glass is shown to exhibit a reversible temperature-induced absorption edge shift at temperatures less than the annealing temperature of the glass (< 370 degree(s)C). A dual- wavelength detection scheme based on a reflective grating and bicell photodiode is employed to eliminate the effects

Claudia Sifuentes; Yuri O. Barmenkov; Andrey N. Starodumov; Valery N. Filippov; Andrey A. Lipovskii

2000-01-01

263

Nucleation and crystallisation of transparent, erbium III-doped, oxyfluoride glass-ceramics  

Microsoft Academic Search

A new Er3+-doped oxyfluoride glass-ceramic composition is reported, based on published compositions but with improved glass stability on reheating. A series of heat treatments up to 168 h at 394°C, close to Tg (glass transformation temperature), has been carried out and yielded visually transparent materials. X-ray diffractometry (XRD) has shown that a fluorite-structured phase with lattice parameter 0.574 nm has

L. L Kukkonen; I. M Reaney; D Furniss; M. G Pellatt; A. B Seddon

2001-01-01

264

Study on luminescent property of Tb(3+)-doped silicate nano-scintillating glass.  

PubMed

By optimizing a Tb(3+)-doped silicate nano-scintillating glass matrix, sensitizer and brightening agent components, the processing conditions such as the melting temperature, holding time, atmosphere, and heat treatment were improved, and the temperature of the heat treatment was changed to generate BaF2 nano-crystal in the glass. The resulting nanocrystals have a better rare earth solubility and a lower phonon energy; therefore the luminescent property of Tb(3+)-doped silicate nano-scintillating glass has been noticeably improved. PMID:20355612

Jingwen, Lv; Xu, Yang; Shengchun, Xiao; Tao, Zheng

2010-03-01

265

Raman spectra of soda–lime–silicate glass doped with rare earth  

Microsoft Academic Search

Soda–lime–silicate glasses doped with different rare earth oxides (La2O3, CeO2, Nd2O3, Gd2O3 and Y2O3) of 1mol% content were prepared by the traditional melting–quenching methods. In order to reveal the effects of rare earth elements on the behavior of soda–lime–silicate glass the structures of soda–lime–silicate glasses doped with different rare earth oxides were determined using an INVIA confocal microRaman spectrometer equipped

Mitang Wang; Jinshu Cheng; Mei Li; Feng He

2011-01-01

266

Structure and properties of soda lime silicate glass doped with rare earth  

Microsoft Academic Search

Soda-lime-silicate glasses doped with different rare-earth oxides (La2O3, CeO2, Nd2O3, Gd2O3 and Y2O3) of 1mol% content were prepared with the traditional melting–quenching methods. In order to reveal the effects of rare-earth elements on the behavior of soda-lime-silicate glass, the structure of soda-lime-silicate glasses doped with different rare-earth oxides were determined with Fourier transform infrared spectrometer using the KBr method, and

Mi-Tang Wang; Jin-Shu Cheng; Mei Li; Feng He

2011-01-01

267

Broadband near-infrared emission from transparent Ni{sup 2+}-doped silicate glass ceramics  

SciTech Connect

Transparent Ni{sup 2+}-doped MgO-Al{sub 2}O{sub 3}-TiO{sub 2}-SiO{sub 2} glass ceramics were prepared, and the optical properties of Ni{sup 2+}-doped glass ceramics were investigated. Broadband emission centered at 1320 nm was observed by 980 nm excitation. The longer wavelength luminescence compared with Ni{sup 2+}-doped Li{sub 2}O-Ga{sub 2}O{sub 3}-SiO{sub 2} glass ceramics is ascribed to the low crystal field hold by Ni{sup 2+} in MgO-Al{sub 2}O{sub 3}-TiO{sub 2}-SiO{sub 2} glass ceramics. The change in optical signals at the telecommunication bands with or without 980 nm excitation was also measured when the seed beam passes through the bulk gain host.

Zhou Shifeng; Dong Huafang; Zeng Heping; Wu Botao; Zhu Bin; Yang Hucheng; Xu Shiqing; Wan Zhiyu; Qiu Jianrong [State Key Laboratory of Silicon Materials, Zhejiang University, Hangzhou 310027 (China); Key Laboratory of Optical and Magnetic Resonance Spectroscopy, Department of Physics, East China Normal University, Zhongshan North Road 3663, Shanghai 200062 (China); Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Shanghai 201800 (China); State Key Laboratory of Silicon Materials, Zhejiang University, Hangzhou 310027 (China)

2007-09-15

268

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

269

Enhanced broadband near-infrared luminescence in Bi-doped glasses by co-doping with Ag  

NASA Astrophysics Data System (ADS)

Enhanced broadband near-infrared luminescence has been observed in Bi-doped oxyfluoride glasses excited from UV to near-infrared regions with the addition of AgCl. Enhancement factors depend greatly on excitation wavelength and maximal enhancement factor over three times occurs at the excitation wavelength around 320, 640, and 800 nm. Ag species play dual functions. The mechanism of the enhancement is discussed in depth combing the energy transfer from Ag+, molecular-like, nonplasmonic Ag species, Bi3+ and Bi2+ to near-infrared bismuth active centers, and the redox reaction of Bi species with Ag species. These results offer a valuable way to enhance the near-infrared luminescence efficiency of Bi-doped glasses, and the dual functions of Ag species may also be employed to enhance luminescence of rare-earth and transition metal ions doped materials.

Xu, Beibei; Chen, Ping; Zhou, Shifeng; Hong, Zhanglian; Hao, Jianhua; Qiu, Jianrong

2013-05-01

270

Preparation of Nd 2O 3-doped calcium aluminosilicate glasses and thermo-optical and mechanical characterization  

Microsoft Academic Search

The calcium aluminosilicate glass (CAS) is an important class of optical materials due to the many applications envisaged, including its use as active media for glass lasers. In order to study how Nd2O3 doping affects the mechanical and the thermo-optical properties of CAS glass, two series of CAS glass, doped with Nd2O3 up to 5wt%, were prepared in a vacuum

A. Steimacher; M. J. Barboza; A. M. Farias; O. A. Sakai; J. H. Rohling; A. C. Bento; M. L. Baesso; A. N. Medina; C. M. Lepienski

2008-01-01

271

Control of surface free energy in titanium doped phosphate based glasses by co-doping with zinc.  

PubMed

To significantly improve the biocompatibility of titanium doped phosphate based glasses, codoping with zinc has been attempted. This study investigated the effect of doping a quaternary 15Na(2)O:30CaO:5TiO(2):50P(2)O(5) glass with zinc oxide (1, 3, and 5 mol %) on bulk, structural, surface, and biological properties; the results were compared with glasses free from ZnO and/or TiO(2). ZnO as adjunct to TiO(2) was effective in changing density, interchain bond forces, degradation behavior, and ions released from the degrading glasses. Incorporation of both TiO(2) and ZnO in T5Z1, T5Z3, and T5Z5 glasses reduced the level of Zn(2+) release by two to three orders of magnitude compared with glasses containing ZnO only (Z5). (31)P NMR results for T5Z1, T5Z3, and T5Z5 glasses showed the presence of Q(3) species suggesting that the TiO(2) is acting as a network former, and the phosphate network becomes slightly more connected with increasing ZnO incorporation. Regardless of their relative lower hydrophilicity and surface reactivity compared with the control glass free from TiO(2) and ZnO (T0Z0), these glasses have significantly higher surface reactivity compared with Thermanox. This has been also reflected in the maintenance of >98% viable Osteoblasts, proliferation rate, and expression level of osteoblastic marker genes in a comparable manner to Thermanox and T5 glasses, particularly T5Z1 and T5Z3 glasses. However, T0Z0 and Z5 glasses showed significantly reduced viability compared to Thermanox. Therefore, it can be concluded that ZnO doped titanium phosphate glasses, T5Z1 and T5Z3 in particular, can be promising substrates for bone tissue engineering applications. PMID:18837445

Neel, Ensanya Ali Abou; O'Dell, Luke Austin; Chrzanowski, Wojciech; Smith, Mark Edmund; Knowles, Jonathan Campbell

2009-05-01

272

Towards a high-performance optical gain medium based on bismuth and aluminum co-doped germanate glass  

Microsoft Academic Search

In this paper we present the development process of glass based on bismuth and aluminum co-doped germanate (GAB) glass. We found the addition of PbO to this glass (GAPB glass) increased the quantum efficiency (QE). Excitation of GAPB glass at 808nm produced emission peaking at 1230nm with a width of 260nm, indicating the glass may be useful as a broadband

M. Hughes; T. Suzuki; Y. Ohishi

2010-01-01

273

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

274

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

PubMed

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

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

2010-07-01

275

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

NASA Astrophysics Data System (ADS)

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 (?=500fs, ?=1045nm, f=0.1-5MHz) from an Ybfiber laser is focused with a microscope objective in the volume of the glass materials and scanned below the surface with different scan velocities and pulse energies. Non-linear absorption processes like multiphoton- and avalanche absorption lead to localized density changes and the formation of color centers. The refractive index change is localized to the focal volume of the laser radiation and therefore, a precise control of the modified volume is possible. The width of the written structures is analyzed by transmission light microscopy and additionally with the quantitative phase microscopy (QPm) software to determine the refractive index distribution perpendicular to a waveguide. Structures larger than 50?m in width are generated at high repetition rates due to heat accumulation effects. In addition, the fabricated waveguides are investigated by far-field measurements of the guided light to determine their numerical apertures. Using interference microscopy the refractive index distribution of waveguide cross-sections in phosphate glass IOG is determined. Several regions with an alternating refractive index change are observed whose size depend on the applied pulse energies and scan velocities.

Esser, D.; Wortmann, D.; Gottmann, J.

2009-02-01

276

Upconverted fluorescence in Er-doped ZBLAN glasses for high efficiency solar cells  

NASA Astrophysics Data System (ADS)

Transparent erbium-doped fluorozirconate (FZ) glasses are attractive systems for upconversion-based solar cells. Upconverted fluorescence intensity vs. excitation power dependence was investigated for a series of erbium-doped FZ glasses. It was found that the ratio of the 2-photon upconverted emission in the near infrared at 980 nm to the 3-photon upconverted emissions in the visible at 530, 550, and 660 nm decreases with increasing excitation power. The integrated upconverted fluorescence intensity per excitation power shows "saturation" upon increasing the excitation power, while the point of saturation shifts to lower excitation power with increasing erbium doping level. To demonstrate the potential of these upconverters for photovoltaic applications, the external quantum efficiency (EQE) of a commercial monocrystalline silicon solar cell with an Er-doped FZ glass on top of it was measured. For an excitation power of 1 mW at a wavelength of 1540 nm an EQE of 1.6% was found for a 9.1 mol% Er-doped FZ glass. The samples investigated were not optically coupled to the solar cell and no optical coating was applied to the glass surface.

Henke, Bastian; Ahrens, Bernd; Johnson, Jacqueline A.; Miclea, Paul T.; Schweizer, Stefan

2009-08-01

277

Structure and distortion of lead fluoride nanocrystals in rare earth doped oxyfluoride glass ceramics.  

PubMed

A series of rare earth (RE) doped oxyfluoride glasses with the composition of (45-x) SiO2-5Al2O3-40PbF2-10CdF2-xRe2O3 (x = 1, 5, 10, 15) (mol%) were prepared by a traditional melt-quenching method. Glass ceramics (GCs) were obtained after thermal treatment and characterized by X-ray diffraction (XRD) to investigate the nanocrystal structure and distortion. Both the dopant type and the doping level play an important role in the distortion of the PbF2-RE lattice. It is found that a cubic Pb3REF9 phase forms in low doping GCs, a tetragonal PbREF5 phase forms in middle doping GCs and cubic PbRE3F11 forms in high doping GCs. Accordingly, the site symmetry of RE(3+) dopants in ?-PbF2 nanocrystal undergoes a transition of OhD4hOh with the increase of doping level. The change in the ligands coordinating the RE(3+) ions was further illustrated by the optical changes in Yb-doped GCs. This paper provides insights on the nanocrystal structure of RE at the atomic level and tries to make a complete description of the nanocrystal structure and distortion in these glass-ceramic materials, which will benefit the optimization of optical properties. PMID:24019159

Ge, Jin; Zhao, Lijuan; Guo, Hui; Lan, Zijian; Chang, Lifen; Li, Yiming; Yu, Hua

2013-09-25

278

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

279

Enhancement of upconversion luminescence due to the formation of nanocrystals in Er3+-doped tellurite glasses  

NASA Astrophysics Data System (ADS)

Optically transparent Er3+-doped tellurite-based nanocrystallized glasses with the composition of 70TeO2-15Li2O-15Nb2O5-0.5Er2O3 (mol) have been prepared by a conventional melting quenching and the subsequent heat treatment processes. The sizes of grown nanocrystals in glass matrix appear to be 35-50 nm from the X-ray diffraction (XRD) measurement. The microhardness measurement shows that the Vickers hardness values of the nanocrystallized tellurite glasses are larger (33%-62%) than those in the base glass. The Raman spectra imply that the maximum phonon energy of the based glass decreases and shifts from 668 to 638 /cm after heat-treatment. Visible upconversion luminescence and infrared luminescence of the base glass and heat-treated glasses under 980-nm laser diode (LD) excitation are investigated. The 524-, 546- and 656-nm upconversion intensities by 980-nm pumping increase significantly.

Zhou, Gang; Dai, Shixun; Yu, Chunlei; Zhang, Junjie; Wang, Guonian; Wen, Lei; Jiang, Zhonghong

2006-01-01

280

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

NASA Astrophysics Data System (ADS)

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

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

2012-05-01

281

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

SciTech Connect

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

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

2001-06-18

282

Nonlinear-optic and ferroelectric behavior of lithium borate-strontium bismuth tantalate glass-ceramic composite  

NASA Astrophysics Data System (ADS)

Transparent glasses in the system (100-x) Li2B4O7-xSrBi2Ta2O9 (0<=x<=20) were fabricated via a splat-quenching technique. The glassy nature of the as-quenched samples was established by differential thermal analyses. X-ray powder diffraction and transmission electron microscopic studies confirmed the amorphous nature of the as-quenched and crystallinity (40 nm) in the heat-treated (glass-ceramic) samples. The dielectric constant (?r) of the glass-ceramic composite (x=20, heat treated at 773 K/8 h) was in between that of the parent host glass (Li2B4O7) and strontium bismuth tantalate ceramics in the frequency range 100 Hz-40 MHz at 300 K. These exhibited intense second-harmonic generation and a ferroelectric hysteritic behavior (P vs E loops) at 300 K. The coercive field (Ec) and the remnant polarization (Pr) were 1053 V/cm and 0.483 ?C/cm2, respectively.

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

2001-06-01

283

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.

2012-02-01

284

Scintillation property of rare earth-free SnO-doped oxide glass  

NASA Astrophysics Data System (ADS)

The authors have demonstrated scintillation of rare earth (RE)-free Sn-doped oxide glass by excitation of ionizing radiation. It is notable that light emission is attained for RE-free transparent glass due to s2-sp transition of Sn2+ centre and the emission correlates with the excitation band at 20 eV. We have also demonstrated that excitation band of emission centre can be tuned by the chemical composition of the host glass. The present result is valuable not only for design of RE-free inorganic amorphous oxide scintillator but also for revealing the band structure of oxide glass by irradiation of ionizing radiation.

Masai, Hirokazu; Yanagida, Takayuki; Fujimoto, Yutaka; Koshimizu, Masanori; Yoko, Toshinobu

2012-11-01

285

Metastable defects induced by X-ray irradiation in Fe-doped soda-lime silicate glass  

NASA Astrophysics Data System (ADS)

Iron is the most important impurity in the commercial soda-lime silicate glasses. Defects induced by X-ray irradiation in the Fe-doped soda-lime silicate glass were studied by means of optical spectrophotometric and electron spin resonance measurements. The defects resulted in two absorption peaks at 610 and 425 nm which were observed in the Fe-doped glass after X-ray radiation. The induced defects were unstable at room temperature. The long-term fading of induced defects at 610 nm obeyed the first-order kinetics. The half-life time of absorption band at 610 nm for the base glass and Fe-doped glass were found to be about 8 and 20 years, respectively. The Fe-doped glass showed better long-term stability of induced color than the base glass.

Zhang, Jian; Sheng, Jiawei

2013-03-01

286

Quantum efficiency of Nd 3+-doped glasses under sunlight excitation  

Microsoft Academic Search

The internal quantum efficiencies under sunlight and laser excitation were measured directly by an integrating sphere method for tellurite, borosilicate and fluoride glasses. The radiative quantum efficiency was also obtained by Judd–Ofelt analysis. The radiative quantum efficiency was almost 100% for tellurite and fluoride glasses and 50% for borosilicate glasses. The quantum efficiency under laser excitation was 86%, 34% and

Takenobu Suzuki; Hiroyuki Kawai; Hiroyuki Nasu; Mark Hughes; Yasutake Ohishi; Shintaro Mizuno; Hiroshi Ito; Kazuo Hasegawa

2011-01-01

287

Blue upconversion luminescence in Tm^(3+)/Yb^(3+) co-doped new oxyfluoride tellurite glass  

NASA Astrophysics Data System (ADS)

The thermal stability, Raman spectrum and upconversion properties of Tm^(3+)/Yb^(3+) co-doped new oxyfluoride tellurite glass are investigated. The results show that Tm^(3+)/Yb^(3+) co-doped oxyfluoride tellurite glass possesses good thermal stability, lower phonon energy, and intense upconversion blue luminescence. Under 980-nm laser diode (LD) excitation, the intense blue (475 nm) emission and weak red (649 nm) emission corresponding to the 1G4 -> 3H6 and 1G4 -> 3F4 transitions of Tm^(3+) ions respectively, were simultaneously observed at room temperature. The possible upconversion mechanisms are evaluated. The intense blue upconversion luminescence of Tm^(3+)/Yb^(3+) co-doped oxyfluoride tellurite glass can be used as potential host material for the development of blue upconversion optical devices.

Xu, Shiqing; Ma, Hongping; Fang, Dawei; Zhang, Zaixuan; Hu, Lili; Jiang, Zhonghong

2005-09-01

288

Structural evaluation and shielding behavior of gamma irradiated vanadium doped silicophosphate glasses  

NASA Astrophysics Data System (ADS)

Ultraviolet and visible spectroscopic studies of base undoped and V2O5-doped sodium silicophosphate glasses were carried out in order to characterize the valence states of vanadium ions in such host mixed glass forming oxides. The same spectroscopic measurements were repeated after subjecting the glass to gamma irradiation with a dose of 8 Mrad (8 × 104 Gy). The base glass without V2O5 reveals an UV absorption band which is related to the presence of unavoidable trace iron impurities within the chemicals used for the preparation of this glass. V2O5-doped glasses exhibit extended UV-visible absorption spectra which are attributed to the collective presence of vanadium ions in three possible valencies V3+, V4+ and V5+ with the lower valence predominating.Infrared absorption spectra of the prepared samples indicate the combined presence of vibrational bands due to the sharing of both phosphate and silicate networks in the IR spectra. The addition of V2O5 in the doping level (0.1-3%) did not cause obvious changes in the IR spectra. Gamma irradiation produces noticeable but limited UV-visible spectral variations which show some shielding behavior in some cases. X-ray diffraction technique was applied to confirm the amorphous nature of the prepared glasses. ESR spectral data confirm the optical spectra results indicating the presence of both V3+ and V4+ ions in measurable percent.

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

2012-09-01

289

Structural, Dielectric, Pyroelectric and Ferroelectric Properties of Glass Nano Composite: Lithium Borate-Strontium Bismuth Vanadium Niobate  

Microsoft Academic Search

Transparent glasses in the system (100 ? x) (Li2O ? 2B2O3) ? x (SrO ? Bi2O3 ? 0.7 Nb2O5 ? 0.3 V2O5) (10 ? x ? 60, in molar ratio) were fabricated via the melt quenching technique. The as-quenched samples were X-ray amorphous. Differential thermal analysis (DTA) confirmed the glassy nature of the as-quenched samples. Strontium bismuth vanadium niobate nanorods

B. HARIHARA VENKATARAMAN; K. B. R. VARMA

2006-01-01

290

Electron, hole and exciton self-trapping in germanium doped silica glass from DFT calculations with self-interaction correction  

Microsoft Academic Search

Density functional theory (DFT) calculations were employed to understand the refractive index change in germanium doped silica glasses for the trapped states of electronic excitations induced by UV irradiation. Local structure relaxation and excess electron density distribution were calculated upon self-trapping of an excess electron, hole, and exciton in germanium doped silica glass. The results show that both the trapped

Jincheng Du; L. René Corrales; Kiril Tsemekhman; Eric J. Bylaska

2007-01-01

291

Model of laser cooling in the Yb3+ -doped fluorozirconate glass ZBLAN  

Microsoft Academic Search

A quantitative description of optical refrigeration in Yb3+ -doped ZBLAN glass in the presence of transition-metal and OH impurities is presented. The model includes the competition of radiative processes with energy migration, energy transfer to transition-metal ions, and multiphonon relaxation. Molecular dynamics calculations of pure ZBLAN and ZBLAN doped with transition-metal ions provide the structural information that, when combined with

Markus P. Hehlen; Richard I. Epstein; Hiroyuki Inoue

2007-01-01

292

Er3+- and Yb3+- doped phosphate glasses for eye-safe laser systems  

NASA Astrophysics Data System (ADS)

Erbium doped optical glasses are effective media for active lasers generating eye safe radiation of a wavelength 1.53 divided by 1.55 micrometers . Development of erbium glass laser systems requires investigations aimed at improvement in glass properties and increase in effectiveness of laser radiation generation. Phosphate glass samples with various Cr2O3, Yb2O3 and Er2O3 contents based upon P2O5-Al2O3-BaO-PbO- K2O oxide system were prepared. The obtained phosphate glasses are characterized by advantageously low thermal expansion coefficient what is important for increase of glass resistance to thermal shock, especially when they are applied as rods for lamp pumped lasers. The effect of changing concentrations of Er3+ and sensitizes Cr3+, Yb3+ as well as glass base compositions on luminescence properties were investigated. The spectral and spectroscopic properties were measured for these glasses. Absorption spectra of these Er3+, Yb3+ and Cr3+-doped glasses were measured in spectral range 190 nm divided by 25 micrometers at room temperature. The excitation and luminescence spectra were also recorded at room temperature on a spectro fluorometer using a diode laser as an excitation source. The presence of hydroxyl groups is an important factor influencing glass structure. In glasses having high concentration of hydroxyl ions, strong attenuation of a lifetime of excited Er3+ ions was stated. In such a case the absorption band around 3.3 micrometers was observed. Concentration of OH groups was reduced due to adequate special melting process of glass. Carried out investigations on thermal, optical, and spectroscopic properties of the obtained glasses showed their good quality, ensuring possibility of their application in laser systems.

Stepien, Ryszard; Jedrzejewski, Kazimierz P.; Kwasny, Miroslaw; Mierczyk, Zygmunt

2001-10-01

293

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

294

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

NASA Astrophysics Data System (ADS)

The increasing demand for energy and the necessity to overcome the depletion of fossil fuel supplies requires that alternative energy sources be developed. Solid Oxide Fuel Cells (SOFCs) are one of the alternative technologies to minimise our dependence on fossil fuel due to their numerous advantages including high efficiency, long-term stability, fuel flexibility and low emissions. However, the development of reliable sealing techniques remains a crucial challenge to overcome to allow usable efficiency and facilitate commercialization. Sealing technology has been object of research for several years. Nevertheless, the optimal solution is yet to be found. The use of a glass composite approach is attractive as it allows the possibility of engineering the properties of the seal, by independently adjusting the particle size distribution and volume fraction of the additives. In the present work, the interaction between various SiO2 based glasses with nickel and B2O3 based glasses with silver were studied. Results as a function of additive particle size distribution (7-100 microns) and volume fraction (0-18%) will be presented. Micrographs, X-ray patterns and CTE measurements showed that the proposed systems have adequate characteristics for usage as seal for fuel cells due to the inertness of the additive particles with the respective glass matrix and predictable long-term chemical and thermal stability. The use of DTMA as a technique to calculate the onset of residual stresses, explores the influence of the additive and its interfacial interactions on the dissipation of energy during deformation. The multi-frequency test lead to an activation energy for stress relaxation between 400 and 600 kJ/mol depending on the different additive content. Furthermore, the temperature difference between de Tg and the onset of residual stresses was calculated showing that increments on the additive content results on a larger temperature range that allows stress relaxation. The mechanical response under compression test was also investigated to identify the potential deformation of a stack during service. The results showed that the glass composites can experience large deformations during the entire service cycle and not only during the isothermal service hold. Moreover, the microstructure in terms of crystalline phase evolves with the test temperature and the applied force, showing an increase of the crystals volume fraction when either the temperature of the applied load increase. The microstructures showed that the additive is getting aligned during deformation, providing an increased resistance to compression against flow of the viscous glass composite. Finally the measurement of the residual stresses as function of cooling rate and additive content revealed that the residual stresses development is minimised for a combination of service conditions including cooling rate under 20 °C/min and glass composite containing a minimum of 12 %vol. Such operating conditions should contribute to maximise the service life of a SOFC stack.

Aguilar-Diaz, Yaneth

295

Luminescence of europium-doped BaOBi 2 O 3 B 2 O 3 glasses  

Microsoft Academic Search

We have prepared europium-doped BaO-Bi2O3-B2O3 glasses and investigated the doping effect on the main physicochemical properties and local structure of the glasses. Using\\u000a Judd-Ofelt analysis, we calculated intensity parameters (?2, ?4, and ?6), spontaneous emission probabilities, the radiative lifetime, luminescence branching factors, the quantum yield of luminescence,\\u000a and the stimulated emission cross sections for 5\\u000a D\\u000a 0 ? 7\\u000a F

A. V. Egorysheva; V. D. Volodin; A. A. Chistyakov; Yu. A. Kuzishchin; V. M. Skorikov; T. D. Dudkina

2010-01-01

296

Thermal stability and UV–Vis-NIR spectroscopy of a new erbium-doped fluorotellurite glass  

Microsoft Academic Search

A new transparent bulk glass from the system 76TeO2?·?10ZnO?·?9.0PbO?·?1.0PbF2?·?3.0Na2O doped with Er (TZPPN doped with Er) has been prepared using the conventional melt-quenching method. Results of differential thermal analysis (DTA) measurements indicate good thermal stability of this glass. The refractive indices at different wavelengths, the optical energy gap, the Sellmeier gap energy and the dispersion energy have been estimated. The

El Sayed Yousef; Kamel Damak; Ramzi Maalej; C. Rüssel

2012-01-01

297

Thermal stability and UV–Vis-NIR spectroscopy of a new erbium-doped fluorotellurite glass  

Microsoft Academic Search

A new transparent bulk glass from the system 76TeO2?·?10ZnO?·?9.0PbO?·?1.0PbF2?·?3.0Na2O doped with Er (TZPPN doped with Er) has been prepared using the conventional melt-quenching method. Results of differential thermal analysis (DTA) measurements indicate good thermal stability of this glass. The refractive indices at different wavelengths, the optical energy gap, the Sellmeier gap energy and the dispersion energy have been estimated. The

El Sayed Yousef; Kamel Damak; Ramzi Maalej; C. Rüssel

2011-01-01

298

Radiation damage studies of cerium-doped radiation-resistant lead glass detectors  

NASA Astrophysics Data System (ADS)

Optical absorption measurements have been made on unirradiated and irradiated samples of cerium oxide doped lead silicate particle detector glasses. The addition of CeO2 introduces one prominent and one weak absorption band near the ultraviolet transmission limit. However the CeO2 greatly reduces the rate of formation of the radiation induced absorption. Detector size blocks of lead glass with 0.0, 0.25, and 1.2 weight percent CeO2 were used to determine the energy resolution for 5 GeV electrons. The resolution deteriorates from 12 to 33% as the CeO2 changes from 0.0 to 1.2%. At these CeO2 levels, calculations indicate the yield of doped glass becomes superior to that of undoped glass for doses greater than 500 rad.

Adams, M. R.; Engelmann, R.; Grannis, P. D.; Horstkotte, J.; Godfrey, L.; Linn, S. L.; Marx, M. D.; Timms, J.; Tuts, P. M.; Willins, J.; Ahrens, L.; Aronson, S.; Levy, P. W.; Yamin, P.; Franzini, P.; Youssef, S.; Cutts, D.; Callas, J.

1985-08-01

299

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

2007-12-28

300

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

NASA Astrophysics Data System (ADS)

Rare earth doped glass-ceramics transparent in the infrared region up to 16 ?m have been prepared and studied. The enhancement of the emission of Er3+ ions at 1.54 ?m with increasing crystallinity was demonstrated in a selenium-based glass-ceramic having a composition of 80GeSe2-20Ga2Se3 + 1000 ppm Er. The optical transmission, microstructure and luminescence properties of a base glass and glass-ceramics were investigated. Luminescence intensities up to 7 times greater were obtained in glass-ceramics in comparison to the base glass. These materials are promising candidates for the production of new laser sources in the mid-infrared region.

Hubert, Mathieu; Calvez, Laurent; Zhang, Xiang-Hua; Lucas, Pierre

2013-10-01

301

Radiation damage studies of cerium-doped radiation-resistant lead glass detectors  

Microsoft Academic Search

Optical absorption measurements have been made on unirradiated and irradiated samples of cerium oxide doped lead silicate particle detector glasses. The addition of CeO2 introduces one prominent and one weak absorption band near the ultraviolet transmission limit. However the CeO2 greatly reduces the rate of formation of the radiation induced absorption. Detector size blocks of lead glass with 0.0, 0.25,

M. R. Adams; R. Engelmann; P. D. Grannis; J. Horstkotte; L. Godfrey; S. L. Linn; M. D. Marx; J. Timms; P. M. Tuts; J. Willins; L. Ahrens; S. Aronson; P. W. Levy; P. Yamin; P. Franzini; S. Youssef; D. Cutts; J. Callas

1985-01-01

302

Spectral properties of erbium-doped lead halotellurite glasses for 1.5 ?m broadband amplification  

Microsoft Academic Search

The spectral properties of the Er3+-doped lead halotellurite glasses, PbX2–TeO2 (X=F, Cl, Br), were measured and analyzed with Judd-Ofelt and McCumber theories. These glasses showed high refractive indices, high cross-sections for both absorption and stimulated emission, and very broad bandwidths for the 1.5 ?m band. The bandwidths of the 1.5 ?m band, which have substantial magnetic dipole transition component, increased

Yong Ding; Shibin Jiang; Bor-Chyuan Hwang; Tao Luo; Nasser Peyghambariana; Yusuke Himei; Tomoko Ito; Yoshinari Miura

2000-01-01

303

Radiative properties of Nd-doped transparent glass-ceramics in the lithium aluminosilicate system  

Microsoft Academic Search

We have studied the optical (absorption, luminescence) properties of Nd3+-doped transparent glass-ceramics obtained in the lithium aluminosilicate system. Phase composition of the glass-ceramics has been determined to affect their luminescent characteristics. We have found out that concentration quenching of neodymium fluorescence decreases upon recrystallization of ?-eucryptite solid solutions (SS) into ?-spodumene ones. The effect is due to partitioning of the

U. Kang; T. I Chuvaeva; A. A Onushchenko; A. V Shashkin; A. A Zhilin; Hee-Je Kim; Yung-Gi Chang

2000-01-01

304

Upconversion lasing of a thulium-ion-doped fluorozirconate glass microsphere  

Microsoft Academic Search

Blue and red upconversion lasing of a Tm3+-doped fluorozirconate glass microsphere was demonstrated. Tens-of-micrometer-sized, genuinely spherical glass particles were produced by a melting method with a burner. The single microsphere was pumped by a focused beam of a Nd:YAG laser operating at 1064 nm. Three-photon-excited lasing emission could be observed in 480 and 800 nm regions at room temperature, and

Hideki Fujiwara; Keiji Sasaki

1999-01-01

305

Blue lasing from a stilbenoid-compound-doped glass–clad polymer optical fibre  

Microsoft Academic Search

We report on blue lasing from a step index glass–clad polymer optical fibre doped with a novel fluorescent stilbenoid compound, 1,4-bis(4-diphenylamino-styryl)-benzene. The compound has a very high quantum yield of 0.85 in polystyrene and a relatively large Stokes shift of 50 nm. The glass–clad fibre is fabricated by drawing a liquid solution of polystyrene containing the compound along into a

Takeyuki Kobayashi; Werner J Blau; Hartwig Tillmann; Hans-Heinrich Hörhold

2002-01-01

306

Compositional investigation of YB(3+)-doped glasses for laser-induced fluorescent cooling applications  

Microsoft Academic Search

In this work, a compositional analysis of Yb3+-doped glasses and transparent glass-ceramics was undertaken to determine potential hosts for use in the development of a first-generation optical cryocooler for space-borne remote sensing applications. By pumping to the lower levels of the Yb 3+ 2F5\\/2 manifold, followed by a thermally-driven population redistribution to higher levels within both manifolds of Yb 3+,

Michael Thomas Murtagh

1999-01-01

307

Scintillation luminescence of cerium-doped borosilicate glass containing rare-earth oxide  

Microsoft Academic Search

The properties of high rare-earth-containing borosilicate glasses have been investigated to assess the potential for using these materials to construct electromagnetic calorimeters for particle physics. We report here on measurements of scintillation yield, transmission and decay time, on large blocks of Ce3+-doped Gd2O3-based glasses. The samples were excited by a high energy X-ray beam and the associated scintillation yield and

Chun Jiang; Qingji Zeng; Fuxi Gan

2000-01-01

308

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

SciTech Connect

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

Hehlen, Markus P [Los Alamos National Laboratory; Bennett, Bryan L [Los Alamos National Laboratory; Williams, Darrick J [Los Alamos National Laboratory; Muenchausen, Ross E [Los Alamos National Laboratory; Castro, Alonso [Los Alamos National Laboratory; Tornga, Stephanie C [Los Alamos National Laboratory

2009-01-01

309

Formation process of Cd and Zn chalcogenide-doped glasses via gels containing thiourea or selenourea complexes  

Microsoft Academic Search

The formation process of glasses doped with cadmium and zinc sulfide or selenide microcrystallites has been studied, along with the characterization of the glasses obtained. Sulfide microcrystallite-doped SiO2 glasses were prepared by the heat-treatment at around 400 degree(s)C of gels in which thiourea complexes were confined. The formation of thiourea complexes of Cd(NO3)2 and Zn(NO3)2 in the starting solutions to

Noboru Tohge; Tsutomu Minami

1992-01-01

310

Silver ion dynamics in silver borate glasses: spectra and multiple-time correlation functions from 109Ag-NMR.  

PubMed

The motion of silver ions in (AgI)x-(Ag2O-B2O3)1-x glasses with AgI concentrations of x=0.5 and 0.7 was studied using 109Ag-NMR. The NMR spectra were analyzed in terms of a superposition of two different contributions. These are associated with Ag ions, which hop on vastly different time scales. The existence of dynamic heterogeneity, i.e. the existence of slow and of fast contributions to the hopping dynamics was directly demonstrated using a four-time stimulated-echo experiment. The results are compatible with an intrinsically exponential response. From measurements of the spectra and of two-time correlation functions a Gaussian distribution of energy barriers, hindering the ionic motion, could be mapped out. PMID:15589733

Berndt, S; Jeffrey, K R; Küchler, R; Böhmer, R

2005-01-01

311

Compositional optimization of bismuth-doped yttria–alumina–silica glass  

Microsoft Academic Search

We fabricated three series of glasses in which the Y2O3, Bi2O3 and Al2O3 contents of Bi-doped Y2O3:Al2O3:SiO2 glass were varied. We optimized the content of each component based on quantum efficiency (QE) and other optical properties. The strength of the Bi absorption bands decreased with increasing Y2O3 content. The optimized composition was: 63.5SiO2:22.5Al2O3:13Y2O3:1Bi2O3. With 808nm excitation this glass had a

M. A. Hughes; T. Suzuki; Y. Ohishi

2009-01-01

312

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

NASA Astrophysics Data System (ADS)

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

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

2012-07-01

313

Long Fluorescence Lifetime of Ti3+-Doped Low Silica Calcium Aluminosilicate Glass  

NASA Astrophysics Data System (ADS)

This Letter reports the formation of Ti3+ in OH- free aluminosilicate glass melted under vacuum condition, with a very long lifetime (170?s) and broad emission band shifted towards the visible region. This lifetime value was attributed to the trapping of the excited electrons by the glass defects and detrapping by thermal energy, and it is 2 orders of magnitude higher than those published for Ti3+ doped materials. Our results suggest that this glass is a promising system to overcome the challenge of extending the spectral range of traditional tunable solid state lasers towards the visible region.

Andrade, L. H. C.; Lima, S. M.; Novatski, A.; Udo, P. T.; Astrath, N. G. C.; Medina, A. N.; Bento, A. C.; Baesso, M. L.; Guyot, Y.; Boulon, G.

2008-01-01

314

Long fluorescence lifetime of Ti3+-doped low silica calcium aluminosilicate glass.  

PubMed

This Letter reports the formation of Ti3+ in OH- free aluminosilicate glass melted under vacuum condition, with a very long lifetime (170 micros) and broad emission band shifted towards the visible region. This lifetime value was attributed to the trapping of the excited electrons by the glass defects and detrapping by thermal energy, and it is 2 orders of magnitude higher than those published for Ti3+ doped materials. Our results suggest that this glass is a promising system to overcome the challenge of extending the spectral range of traditional tunable solid state lasers towards the visible region. PMID:18232921

Andrade, L H C; Lima, S M; Novatski, A; Udo, P T; Astrath, N G C; Medina, A N; Bento, A C; Baesso, M L; Guyot, Y; Boulon, G

2008-01-18

315

Synthesis and evaluation of ultra-pure rare-earth-doped glass for laser refrigeration  

NASA Astrophysics Data System (ADS)

Significant progress has been made in synthesizing and characterizing ultra-pure, rare-earth-doped ZIBLAN (ZrF4-InF3- BaF2-LaF3-AlF3-NaF) glass capable of laser refrigeration. Yb3+-doped ZIBLAN glass was produced from fluoride precursors which were individually purified by solvent extraction and subsequently treated with hydrofluoric gas at elevated temperatures to remove oxygen impurities. We have developed two-band differential luminescence thermometry (TBDLT) as a new non-invasive, spectroscopic technique to evaluate the intrinsic quality of Yb3+ doped laser-cooling samples. TBDLT measures changes in the local temperature upon laser excitation via the small changes in the 2F5/2-->2F7/2 fluorescence spectrum. Two commercial band pass filters in combination with a balanced dual InGaAs photodetector are used to select and integrate regions of interest in the fluorescence spectrum with sub-millisecond resolution. The TBDLT technique successfully finds the zero-crossing temperature (ZCT), which is the minimum temperature to which a Yb3+ doped sample can cool, independent of surface heating. ZCT is a useful measure for the presence of impurities and the overall quality of the laser-cooling material. Favorable laser cooling results were obtained for several 1% Yb3+-doped glasses with varying degrees of purity.

Patterson, Wendy M.; Hehlen, Markus P.; Sheik-Bahae, Mansoor; Epstein, Richard I.

2009-02-01

316

Emission from a bismuth doped chalcogenide glass spanning from 1 mum to 2.7 mum  

Microsoft Academic Search

In this paper we report emission from Bi doped gallium lanthanum sulphide (Bi:GLS) glass with a full width at half maximum (FWHM) of 600 nm which is flattened and covers the entire telecommunications window. The excitation wavelength of this emission was 1020 nm, the quantum efficiency (QE) was 17%, the lifetime was 160 mus and product of the emission cross

M. A. Hughes; T. Suzuki; Y. Ohishi

2011-01-01

317

Multiphoton upconversion process in Tm3+ doped ZBLAN glass by CW laser irradiation  

NASA Astrophysics Data System (ADS)

Blue, even ultraviolet emissions and very strong red emissions have been observed in ZBLAN glass doped with Tm3+ under 800 nm CW laser excitation. The red emissions were demonstrated to be of sequential two-photon process, while the ultraviolet emissions be of three-photon process, according to the intensity dependence.

Li, Jianfu; Wang, Xiaoli; Jiang, Zhankui

2009-11-01

318

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

Microsoft Academic Search

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

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

2006-01-01

319

Waveguide fabrication in Nd3{plus} and Yb3{plus} doped phosphate glasses  

SciTech Connect

We report on planar waveguides formed by field assisted ion exchange in Nd{sup 3+} and Yb{sup 3+} doped phosphate glasses. Losses of 0.71 dB/cm are measured. Electron probe measurements confirm Ag{sup +} diffusion.

Patel, F.D.; Honea, E.C.; Krol, D.; Payne, S.A.; Hayden, J.S.

1998-03-02

320

Comparison of optical properties of pure and doped lithium tetraborate single crystals and glasses  

NASA Astrophysics Data System (ADS)

High optical quality Li2B4O7 (LTB) single crystals and glassy phases of pure, doped (Cu, Ag) and co-doped with Cu+Ag have been grown by Czochralski crystal pulling and melt quenching techniques respectively. They were characterized through photoluminescence (PL), thermoluminescence (TL), and UV-VIS-NIR transmission measurements. The PL of glass phase shows light yield comparable to that of single crystal. 80-85 % optical transmission in the range 350-800 nm revealed good optical quality of the glasses which is comparable to the single crystals though the glasses have higher cut off wavelength (lower energy). TL glow peaks of Cu doped LTB single crystal at 200 °C and for Cu+Ag co-doped LTB single crystals at around 170°C and 240°C are useful for the dosimetry applications and found to be linear in the range from 1mGy to 1kGy. However, in glasses no TL was observed in spite of a good PL yield.

Patra, G. D.; Singh, A. K.; Singh, S. G.; Tyagi, M.; Sen, S.; Tiwari, B.; Gadkari, S. C.

2012-06-01

321

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

SciTech Connect

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

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

2012-07-01

322

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

NASA Astrophysics Data System (ADS)

An investigation of donor-acceptor energy transfer kinetics in dual rare earths doped precursor oxy-fluoride glass and its glass-ceramics containing NaYF4 nano-crystals is reported here, using three different donor-acceptor ion combinations such as Nd-Yb, Yb-Dy, and Nd-Dy. The precipitation of NaYF4 nano-crystals in host glass matrix under controlled post heat treatment of precursor oxy-fluoride glasses has been confirmed from XRD, FESEM, and transmission electron microscope (TEM) analysis. Further, the incorporation of dopant ions inside fluoride nano-crystals has been established through optical absorption and TEM-EDX analysis. The noticed decreasing trend in donor to acceptor energy transfer efficiency from precursor glass to glass-ceramics in all three combinations have been explained based on the structural rearrangements that occurred during the heat treatment process. The reduced coupling phonon energy for the dopant ions due to fluoride environment and its influence on the overall phonon assisted contribution in energy transfer process has been illustrated. Additionally, realization of a correlated distribution of dopant ions causing clustering inside nano-crystals has also been reported.

Sontakke, Atul D.; Annapurna, K.

2012-07-01

323

Optical properties of samarium doped zinc-tellurite glasses  

Microsoft Academic Search

Glasses with the composition, (Sm2\\u000a O\\u000a 3)\\u000a x\\u000a (ZnO)(40-x)(TeO\\u000a 2)(60), were prepared by conventional melt quenching method. The density, molar volume, and optical energy band gap of these glasses\\u000a have been measured. The refractive index, molar refraction and polarizability of oxide ion have been calculated by using Lorentz-Lorentz\\u000a relations. Optical absorption spectra of these glasses were recorded in the range

B. Eraiah

2006-01-01

324

Optical and structural investigation on rare-earth-doped aluminophosphate glasses  

NASA Astrophysics Data System (ADS)

Aluminophosphate glasses belonging to the oxide system Li2O BaO Al2O3 La2O3 P2O5, un-doped and doped with rare-earth metal ions (Ce4+, Nd3+, Sm3+) were obtained by a wet non-conventional method. The influence of the doping ions on the optical properties of the phosphate glasses has been investigated in relation with structural features of the vitreous matrix. The optical behavior has been studied by ultra-violet visible near-infra-red (UV VIS NIR) spectroscopy, revealing electronic transitions specific for rare-earth ions. Structural information via optical phonons was provided by infrared (IR) absorption spectra in the range 400 4000 cm-1. Raman and fluorescence spectroscopy measurements have been performed. A strong fluorescence was observed in the visible spectrum, using 514.5 nm and 633 nm laser excitation.

Elisa, M.; Cristina Vasiliu, I.; Grigorescu, Cristiana E. A.; Grigoras, Bogdan; Niciu, Horatiu; Niciu, Daniela; Meghea, Aurelia; Iftimie, Nicoleta; Giurginca, Maria; Trodahl, H. J.; Dalley, M.

2006-05-01

325

1310- to 1320-nm emission in Nd3+-ion-doped fluoroaluminate glasses  

NASA Astrophysics Data System (ADS)

Nd3+-doped 1.3micrometers fiber amplifier has many inherent advantages, but two major problems must be overcome to achieve a device: signal excited-state absorption (ESA), and amplified spontaneous emission (ASE). Signal ESA around 1300 nm prevents gain in that region, and so red-shifts and gain out of the second telecom window. The ASE at 1050 nm has a branching ratio 5 time larger than the 1.3 micrometers transition; as a result it clamps signal gain at low values. Moreover, in many Nd3+-doped glass hosts the peak of emission lies at wavelengths above 1320 nm. In this paper we present new highly ionic fluoroaluminate glasses developed as hosts for the 1.3 micrometers -doped fiber amplifier and discuss aspects of glass design. Nd3+ 4F3/2-4I13/2 emission peaks between 1310 and 1317 nm were demonstrated in bulk glasses, and gain in the 1310-1320 nm region was measured in fiber. The gain and emission spectra show evidence of significantly reduced ESA. ASE filtering is discussed, focusing on Bragg grating filters and on absorbing co-dopants, such as Yb(superscript 3+. The paper also assesses thermal and viscous properties of the core and cladding glasses for fiber drawing.

Jha, Animesh; Naftaly, Mira; Taylor, Elizabeth R.; Samson, B. N.; Marchese, Diego; Payne, David N.

1998-09-01

326

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

SciTech Connect

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

Sato, M.; Honma, T.; Benino, Y. [Department of Materials Science and Technology, Nagaoka University of Technology, 1603-1 Kamitomioka-cho, Nagaoka 940-2188 (Japan); Komatsu, T. [Department of Materials Science and Technology, Nagaoka University of Technology, 1603-1 Kamitomioka-cho, Nagaoka 940-2188 (Japan)], E-mail: komatsu@mst.nagaokaut.ac.jp

2007-09-15

327

Thermal analysis, spectral characterization and refractive index studies of lithium doped PbO-ZnO-B2O3 glass  

NASA Astrophysics Data System (ADS)

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°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 [BO3] [BO4]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.

2012-06-01

328

Optimization of host glass composition to make soda borosilicate glasses doped with reduced rare earth ions  

Microsoft Academic Search

Soda borosilicate glasses with various compositions containing 1mol% of Sm3+ were prepared in a reductive atmosphere to reduce Sm3+ ions. For the glass preparation, a multi-sample glass-formation tester was adopted. This apparatus is capable of handling 24 samples at once. The existence of thermally reduced Sm2+ was confirmed by their fluorescent emission spectrum. By using compositional combinatorial approach, the glass-forming

Tomoya Konishi; Takehisa Matsumoto; Tetsuo Araki; Toshio Tsuchiya; Shin-ichi Todoroki; Satoru Inoue

2004-01-01

329

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

330

Low temperature laser cooling with a rare-earth doped glass  

NASA Astrophysics Data System (ADS)

A theoretical study of laser cooling at low temperature by anti-Stokes luminescence in a rare-earth doped glass is performed. A model is developed to evaluate the absorption and emission spectra of rare-earth ions in a glass matrix. This model allows the evaluation of the inhomogeneously broadened spectra at any temperature. It takes into account the saturation effects that occur at high excitation. The model is used to evaluate the cooling capability at low temperature of a ytterbium-doped fluorozirconate glass, the latter having been proposed in the literature as a good candidate for the cooling element of a cryocooler. Results are compared with previous estimations, confirming that one could expect a useful cooling efficiency from this material, but with smaller performances than previously estimated. Limitations to the cooling process are discussed. The reabsorption of luminescence is identified as one of the main limitations to the performance of a potential cryocooler.

Lamouche, G.; Lavallard, P.; Suris, R.; Grousson, R.

1998-07-01

331

Sb3+/Mn2+ co-doped tunable white emitting borosilicate glasses for LEDs.  

PubMed

Luminescent properties of Sb(3+)/Mn(2+) co-doped borosilicate glasses containing no rare earth ions were systematically investigated through absorption, excitation, emission spectra, and decay curves. Upon 250-340 nm light excitation, the glasses exhibit broad blue emission at 400 nm (Sb(3+)) and red emission at 615 nm (Mn(2+)). The varied emitted color from blue through white and eventually to red can be obtained by properly tuning the content of Mn(2+) ions due to energy transfer from Sb(3+) to Mn(2+). Our investigation shows that Sb(3+)/Mn(2+) co-doped glasses may provide a new platform to design and fabricate luminescent materials for UV LED chips in the future. PMID:23073435

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

2012-10-15

332

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

NASA Astrophysics Data System (ADS)

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

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

2013-09-01

333

Progress on up- and down-converted fluorescence in rare-doped fluorozirconate-based glass ceramics for high efficiency solar cells  

Microsoft Academic Search

Transparent glasses as up- or down-converters are attractive systems to increase the efficiency of solar cells. Er-doped fluorozirconate (FZ) glasses show an intense up-conversion upon excitation at 1540 nm. Transmission spectra show that the absorbance at 1540 nm grows linearly with the Er-doping level. In Eu-doped FZ glasses, which were additionally doped with chlorine ions, the growth of BaCl2 nanocrystals

Stefan Schweizer; Bastian Henke; Bernd Ahrens; Christian Paßlick; Paul T. Miclea; Johannes Wenzel; Eduard Reisacher; Wulf Pfeiffer; Jacqueline A. Johnson

2010-01-01

334

Spectroscopic properties of Er doped and Er, Nd codoped fluoride glasses under simulated sunlight illumination  

NASA Astrophysics Data System (ADS)

We investigated the fluorescence characteristics of Er codoped Nd doped ZBLAN glasses proposed for solar pumped fiber laser (SPFL) under simulated sunlight. Er is used as a sensitizer because it absorbs a part of the ultraviolet and visible light where is no absorption of Nd. Under simulated sunlight illumination, Er singly doped fluoride glass displayed four emission bands with peaks at 550, 848, 977 and 1533 nm attributed to the 4S3/2-4I15/2, 4S3/2-4I13/2, 4I11/2-4I15/2 and 4I13/2-4I15/2 electronic transitions of Er, respectively. The quantum efficiency measurement was carried out using an integrating sphere and under the simulated sunlight excitation showed a maximum of 73% for 0.5 mol.% of ErF3 in ZBLAN glass. In Nd, Er codoped fluoride glass, the 1.05 ?m emission of Nd was observed under 380 nm excitation what supposes the energy transfer from Er to Nd in ZBLAN glasses as Nd has no absorption at the wavelength. Er, Nd codoped fluoride glasses are promising as a sensitized laser media for solar pumped fiber lasers.

Mizuno, Shintaro; Ito, Hiroshi; Hasegawa, Kazuo; Kawai, Hiroyuki; Nasu, Hiroyuki; Hughes, Mark A.; Suzuki, Takenobu; Ohishi, Yasutake

2011-10-01

335

The tetragonal structure of nanocrystals in rare-earth doped oxyfluoride glass ceramics.  

PubMed

Rare-earth doped oxyfluoride glasses and nanocrystalline glass ceramics have been prepared and studied by energy dispersive X-ray spectroscopy (EDS) and X-ray diffraction (XRD) aiming at investigating the structure and the symmetry of the nanocrystal as well as the site of the rare-earth ion. To solve the problem encountered by previous researchers due to glass host interference, we etched off glass matrix and released the fluoride nanocrystal, which is more convenient for EDS measurement. A tetragonal phase model with the chemical formula as PbREF(5) proved by quantitative EDS and XRD analyses has been proposed in this paper for the first time. Two specific crystalline phases with the same space group have been observed at 460 °C-500 °C and 520 °C-560 °C, respectively. Moreover, a super "pseudo-cubic" cell based on our tetragonal model may give a good explanation to the probable previous cubic-symmetry misunderstanding by researchers. Additionally, the thermodynamic mechanism of phase transition and the thermal stability related to the structure of nanocrystals in glass ceramics have been studied and supported by ab initio calculations and experimental methods. The structure and thermal stability of the nanocrystal and clear environment of the rare-earth ion reported here have far-reaching significance with respect to the optical investigations and further applications of rare-earth doped oxyfluoride glass ceramics. PMID:21152548

Hu, Nan; Yu, Hua; Zhang, Ming; Zhang, Pan; Wang, Yazhou; Zhao, Lijuan

2010-12-09

336

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

NASA Astrophysics Data System (ADS)

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

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

2013-10-01

337

The Local Structure of Bismuth-Borates Characterized by 11B MAS NMR  

NASA Astrophysics Data System (ADS)

Bismuth-borate glasses and vitroceramics belonging to xBi2O3 . (100 - x) B2O3 system, 0 <= x <= 93, doped with 0.5 mol% MnO are investigated by 11B Magic Angle Spinning Nuclear Magnetic Resonance (MAS NMR). The 11B MAS NMR results indicate the presence of three- and tetra-coordinated boron in all investigated bismuth borates. While the fraction of the tetra-coordinated boron present a large maximum in the range 20 <= x <= 60 in the bismuth-borate glasses, this maximum is reduced to the range 20 <= x <= 37.5 in the samples obtained after heat treatment. Crystalline phases are developed in the samples with high bismuth content, x >= 60, by heat treatment at 550°C, in which two types of three-coordinated boron are identified. The mean values of the NMR parameters like chemical shift, asymmetry parameter and quadrupolar coupling constant are less influenced by the bismuth/boron ratio, showing that boron structural units are relatively stable on the entire investigated composition range.

Vasilescu, M.; Simon, S.

338

Spectroscopic characteristics of chromium doped mullite glass-ceramics  

SciTech Connect

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

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

1988-06-01

339

Low-power continuous-wave nonlinear optics in doped silica glass integrated waveguide structures  

NASA Astrophysics Data System (ADS)

Photonic integrated circuits are a key component of future telecommunication networks, where demands for greater bandwidth, network flexibility, and low energy consumption and cost must all be met. The quest for all-optical components has naturally targeted materials with extremely large nonlinearity, including chalcogenide glasses and semiconductors, such as silicon and AlGaAs (ref. 4). However, issues such as immature fabrication technology for chalcogenide glass and high linear and nonlinear losses for semiconductors motivate the search for other materials. Here we present the first demonstration of nonlinear optics in integrated silica-based glass waveguides using continuous-wave light. We demonstrate four-wave mixing, with low (5 mW) continuous-wave pump power at ? = 1,550 nm, in high-index, doped silica glass ring resonators. The low loss, design flexibility and manufacturability of our device are important attributes for low-cost, high-performance, nonlinear all-optical photonic integrated circuits.

Ferrera, M.; Razzari, L.; Duchesne, D.; Morandotti, R.; Yang, Z.; Liscidini, M.; Sipe, J. E.; Chu, S.; Little, B. E.; Moss, D. J.

2008-12-01

340

Spectroscopic properties of Er3+ doped lead phosphate glasses for photonic application 4-23-2009  

SciTech Connect

The spectroscopic characteristics of Er3+-doped lead phosphate glasses have been investigated, and Judd-Ofelt analysis was used to evaluate the effect of increasing the Er3+ content on the glass matrices. The intensity-dependent Judd=-Ofelt parameters: (4) and (6) remained constant while (2) decreased. Photoluminescence analysis revealed a low up-conversion efficiency through the weak green (530 and 550 nm) and red (660 nm) signals that were present under excitation at 800 nm. The concentration quenching effect on the lifetime of the Er3+: 4I13/2 4I15/2 (1530 nm) transition is also evaluated as a result of the addition of Er3+ to the lead phosphate glass composition. The observed relatively large reduction in the lifetime reflects the significant effects of non-radiative processes in this system. The potential use of these glasses as photonic devices is also discussed.

Santos, C. C. [Universidade Federal do Ceara, Ceara, Brazil; Guedes, I. [Universidade Federal do Ceara, Ceara, Brazil; Moura, A. L. Moura [Instituto de Fisica, Universidade Federal de Alagoas, Brazil; de Araujo, M. T. [Instituto de Fisica, Universidade Federal de Alagoas, Brazil; Jacinto, C. [Instituto de Fisica, Universidade Federal de Alagoas, Brazil; Vermelho, M. V. D. [Instituto de Fisica, Universidade Federal de Alagoas, Brazil; Loong, C. K. [Sun Yat-Sen University, Guangzhou, China; Boatner, Lynn A [ORNL

2010-01-01

341

High Photoluminescent Property of Low-Melting Sn-Doped Phosphate Glass  

NASA Astrophysics Data System (ADS)

The authors report on the quantum efficiency (QE) of UV-excited photoluminescence measured in SnO--ZnO--P2O5 glass developed as rare earth (RE)-free material for light emitting diode (LED) applications; we report what is, to the best of our knowledge, the highest value of QE ever reported. It is notable that the QE value of the present RE-free glass (˜90%) is comparable to that of RE-doped glass. For future LED applications, we have emphasized that the low-melting glass will be one of the most industrially favorable inorganic materials to replace organic sealants that suffer degradation by strong LED irradiation.

Masai, Hirokazu; Takahashi, Yoshihiro; Fujiwara, Takumi; Matsumoto, Syuji; Yoko, Toshinobu

2010-08-01

342

Optical properties of Ce3+-doped sol-gel silicate glasses  

NASA Astrophysics Data System (ADS)

The sol-gel technique has been considered for the preparation of Ce3+-doped silicate scintillating glasses. Ce3+ concentrations in the range 0.1-1mol% have been studied. The structural and optical properties of the glasses have been investigated by several techniques like Raman spectroscopy, radio-luminescence, time resolved luminescence, and wavelength resolved thermally stimulated luminescence. Particular attention has been paid to the influence of the concentration of dopant ions and to the different phases of the xerogel densification process governing the glass formation. The results achieved indicate that Ce3+ activators possess promising optical features in the considered glass matrix both for what concerns the luminescence efficiency and the scintillation decay time (of approximately 50ns under 22Na excitation).

Vedda, A.; Baraldi, A.; Canevali, C.; Capelletti, R.; Chiodini, N.; Francini, R.; Martini, M.; Morazzoni, F.; Nikl, M.; Scotti, R.; Spinolo, G.

2002-06-01

343

Bioactive glass in tissue engineering  

PubMed Central

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

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

2011-01-01

344

The third order optical nonlinear character of ZnSe nanocrystals doped silica glasses  

Microsoft Academic Search

ZnSe\\/SiO2 composites were fabricated with conventional sol–gel synthesis method. The absorption spectra of the semiconductor-doped\\u000a glasses (SDGs) were presented and compared among different ZnSe doping amounts. The energy gap (E\\u000a g) decreased distinctly as the content of ZnSe QDs increased. Nonlinear refractive indexes were measured by single beam Z-scan\\u000a technique. The results revealed that the third order nonlinear susceptibility was

Xing Wan; Xi Yao; Minqiang Wang; Haiyan Hao

2008-01-01

345

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

PubMed

Photodarkening experiments are performed on ytterbium-doped silicate glass samples. A strong charge-transfer (CT) absorption band near 230nm in aluminosilicate glass is found to be correlated to the mechanism of induced color center formation. Excitation into the CT-absorption band generates similar color centers as observed in ytterbium-doped fiber lasers under 915nm high power diode pumping. The position of the CT-absorption band is compositional dependent and is shifted to shorter wavelengths in ytterbium doped phosphosilicate glass. Very low levels of photodarkening is observed for the ytterbium doped phosphosilicate glass composition under 915nm high power diode pumping. Possible excitation routes to reach the CT-absorption band under 915nm pumping are discussed. PMID:18542200

Engholm, M; Norin, L

2008-01-21

346

Cobalt-Doped Transparent Glass Ceramic as a Saturable Absorber Q Switch for Erbium:Glass Lasers  

NASA Astrophysics Data System (ADS)

A new saturable absorber Q switch for 1.54- m Er:glass lasers is presented. The saturable absorber is a transparent glass ceramic that contains magnesium -aluminum spinel nanocrystallites doped with tetrahedrally coordinated Co2 +ions. We obtained Q -switched pulses of up to 5.5 mJ in energy and 80 ns in duration at 1.54 m. The relaxation time of 4A2 4T1 (4F ) transition bleaching was measured to be (450 -/+ 150) ns. Ground-state and excited-state absorption cross sections at 1.54- m wavelength were estimated to be (3.2 -/+ 0.4) x10-19 cm2 and (5.0 -/+ 0.6) x10-20 cm2 , respectively.

Malyarevich, Alexander M.; Denisov, Igor A.; Yumashev, Konstantin V.; Dymshits, Olga S.; Zhilin, Alexander A.; Kang, Uk

2001-08-01

347

Spectroscopic characterization of alkali modified zinc-tellurite glasses doped with neodymium.  

PubMed

Neodymium doped zinc-tellurite glasses of composition TeO(2)-ZnO-Na(2)O-Li(2)O have been prepared and characterized for their thermal, structural and optical properties. Differential thermal analysis revealed reasonably good forming tendency of the glass composition. FTIR spectra were used to analyze the functional groups present in the glass. Judd-Ofelt intensity parameters were derived from the absorption spectrum and used to calculate the radiative lifetime, branching ratio and stimulated emission cross-section for (4)F(3/2)-->(4)I(9/2, 11/2, 13/2) transitions. The quantum efficiency of the (4)F(3/2) level is comparable to the typical values obtained for the Nd(2)O(3)-doped glasses. The decay properties for higher concentration of Nd(2)O(3) were analyzed using Inokuti-Hirayama model to investigate the non-radiative relaxation of the (4)F(3/2) emitting level. The experimental values of branching ratio and saturation intensity of (4)F(3/2)-->(4)I(11/2) transition and calculated spectroscopic quality factor indicate the favourable lasing action in these glasses. PMID:20570210

Rajeswari, R; Babu, S Surendra; Jayasankar, C K

2010-05-06

348

Femtosecond measurement of enhanced optical nonlinearities of sulfide glasses and heavy-metal-doped oxide glasses  

NASA Astrophysics Data System (ADS)

Studies of the nonlinear absorption and refraction of a variety of heavy-metal oxide and sulfide glasses are reported. The third-order nonlinearities were measured with \\similar 100-fs pulses at wavelengths between 600 nm and 1.25 mu m, allowing for what we believe is the first systematic study of the dispersion of the third-order nonlinearities of these glasses. The results confirm that the nonlinearities of heavy-metal oxide glasses are determined by heavy-metal content, as reported previously. The measured nonlinear refractive indices are predicted reasonably well by the semiempirical Boling-Glass-Owyoung formula and include several results that are among the largest nonresonant nonlinearities reported. The measured dispersion of the nonlinearities is consistent with simple theoretical expectations. Finally, most of the glasses obey Kleinman's symmetry, from which we conclude that the origin of the femtosecond-time-scale nonlinearities is electronic. Copyright (c) 1995 Optical Society of America

Kang, I.; Krauss, T. D.; Wise, F. W.; Aitken, B. G.; Borrelli, N. F.

1995-11-01

349

Optical properties of HITC and oxazine-1-doped sol-gel gel glasses  

NASA Astrophysics Data System (ADS)

The lifetime of the near-infrared emission of oxazine-1 and 1,1',3,3,3',3'- hexamethylindotrycarbocyanine iodide (HITC) into gel-glasses prepared from TMOS or TEOS are studied by variable frequency phase and modulation data. Analysis of the lifetime by a fitting procedure to an assumed model revealed two lifetimes with a low value of the reduced chi-squared for the studied doped gel-glasses. The longer lifetime is attributed to the adsorbed species, while the shorter to species which are affected by the remaining solvent in the pores. The contributions of these species to the total fluroescence are also resolved.

del Monte, Francisco; Levy, David

1994-10-01

350

Rare-earth doped transparent glass-ceramics with high cross-sections  

Microsoft Academic Search

Erbium doped oxy-fluoride glass-ceramics (50GeO2,[50?x]PbO,xPbF2) have been prepared by thermal treatments of as-melted glass. The optical absorption and emission cross-sections were measured. The controlled crystallisation of the fluoride compounds by nucleation and growth in the oxide matrix produced crystallites ?10 nm in size and a filling factor of 10?2. The phase separation process was investigated using thermal and structural analysis.

Michel Mortier; Francois Auzel

1999-01-01

351

Optical absorption and luminescence study of cobalt-doped magnesium aluminosilicate glass ceramics  

NASA Astrophysics Data System (ADS)

Linear and nonlinear optical properties of cobalt-doped magnesium aluminosilicate transparent glass ceramics that were prepared under different conditions have been studied. It has been shown that absorption and luminescence spectra and absorption bleaching of these glass ceramics are defined mainly by tetrahedrally coordinated Co 2+ ions located in magnesium aluminum spinel nanocrystals. The lifetimes of the 4 T 1 ( 4 F) and 4 T 2 ( 4 F) excited states of the tetrahedral Co 2+ ions were found to be in the ranges 2540 and 120450 ns, respectively, depending on the Co concentration. 2002 Optical Society of America

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

2002-08-01

352

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

NASA Astrophysics Data System (ADS)

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

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

1996-04-01

353

Infrared to visible up-conversion study for erbium-doped zinc tellurite glasses  

Microsoft Academic Search

Optical absorption and photoluminescence properties of Er3+-doped 70TeO2-30ZnO glass are investigated. Judd-Ofelt intensity parameters of Er3+ have been determined to calculate the radiative transition probabilities and the radiative lifetimes of excited states. An infrared to visible up-conversion was observed at room temperature in this tellurite glass system using a 797 nm excitation line. A study of the 4S3\\/2-4I15\\/2 transition (554

N. Jaba; A. Kanoun; H. Mejri; A. Selmi; S. Alaya; H. Maaref

2000-01-01

354

Time-resolved up-converted luminescence in Er 3+-doped TeO 2–ZnO glass  

Microsoft Academic Search

Here is reported time-resolved up-converted luminescence of Er3+-doped 70TeO2–30ZnO glasses. The photoluminescence shows non-exponential decay. This behaviour is explained as due to a multi-configurational distribution of luminescent ions in a disordered medium. Green and red up-converted fluorescences are obtained under cw laser excitation. Its dynamics, in lightly doped glasses, are mainly explained by an excited-state absorption (ESA) process. In heavily

A. Kanoun; N. Jaba; A. Brenier

2004-01-01

355

Gain and noise characteristics of single-mode Er3+\\/Yb3+ Co-doped phosphate glass fibers  

Microsoft Academic Search

Single-mode highly Er3+\\/Yb3+ co-doped phosphate glass-fiber has been fabricated by rod-in-tube technique. Gain and noise measurements of the phosphate glass fiber have been performed by dual-pump configure with two 976 nm fiber-pigtail LDs using a highly Er3+\\/Yb3+ co-doped phosphate fiber with a length of 5.0 cm. Gain spectra and noise figures with different input signal powers of -30, -10, and

S. H. XU; Z. M. Yang; Z. M. Feng; Q. Y. Zhang; Z. H. Jiang; W. C. Xu

2008-01-01

356

Room-temperature hole-burning and sublinear hole-growth dynamics in an Sm 2+-doped aluminosilicate glass  

Microsoft Academic Search

Aluminosilicate glasses doped with Sm2+-ion can exhibit hole-burning at room temperature. In this paper, we investigate the hole-growth dynamics of Sm2+-ion-doped aluminosilicate glasses prepared by the sol–gel method to reveal the hole-formation at room temperature. We found that the spectral holes exhibit Lorenz profiles. Hole-growth dynamics can be well fitted by the function H(t)=?t?. The hole-growth rate Kt decreases with

Hongwei Song; Masayuki Nogami

2002-01-01

357

DC electrical conductivity study of cerium doped conducting glass systems  

NASA Astrophysics Data System (ADS)

The glass samples of composition 60V2O5-5P2O5-(35-x)B2O3-xCeO2, (1 <= x <= 5) were prepared by the conventional melt quench method. The samples were characterized by X-ray diffraction and thermo gravimetric-differential thermal analysis. The glass transition temperature and crystallization temperature determined from TG-DTA analysis. The DC electrical conductivity has been carried out in the temperature range 303-473 K. The maximum conductivity and minimum activation energy were found to be 0.039 Scm-1 and 0.15 eV at 473 K for x=1, respectively.

Barde, R. V.; Waghuley, S. A.

2013-06-01

358

Erbium-doped glasses for fiber amplifiers at 1500 nm  

Microsoft Academic Search

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

William J. Miniscalco

1991-01-01

359

Energy transfer based NIR to visible upconversion: Enhanced red luminescence from Yb3+/Ho3+ co-doped tellurite glass  

NASA Astrophysics Data System (ADS)

Yb3+-Ho3+: co-doped and Yb3+: singly doped tellurite glasses prepared by conventional melt quenching technique were studied for their sensitised NIR to vis-upconversion performance. The oscillator strength of an absorption transition of the sensitizer (Yb3+) ions was calculated by using the smakula equation from the base glass corrected absorption spectra of Yb3+ singly doped glass. A bright green upconversion emission of Ho3+ ions from the co-doped glass upon exciting Yb3+ ions with 980 nm laser diode and a simultaneous 12 fold decrease in 1.008 ?m emission intensity of Yb3+ ions has been attributed to the energy transfer from sensitizer (Yb3+) to the acceptor (Ho3+) ions. Donor, Yb3+ ion decay kinetics has been analysed by considering Inokuti-Hirayama and Burshtein theoretical models and confirmed the donor-donor hopping migration assisted energy transfer among Yb3+-Ho3+. The energy transfer efficiency estimated from the experimental lifetimes of the singly doped and co-doped system was found to be 85.8%. Further, the upconversion spectra recorded by varying the pump laser power revealed a two photon contribution for the green and red upconversion emission process with the prevalence of saturation. The phenomena of upconversion emissions in the co-doped system were explained with the partial energy level diagram. This glass has been found to be a promising material for the development of solid state upconversion green emitting laser.

Balaji, Sathravada; Mandal, Ashis K.; Annapurna, K.

2012-09-01

360

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

SciTech Connect

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

Oliveira, S. L.; Sousa, D. F. de; Andrade, A. A.; Nunes, L. A. O.; Catunda, T. [Instituto de Fisica de Sao Carlos, Universidade de Sao Paulo, CEP 13560-970, Sao Carlos-Sao Paulo (Brazil)

2008-01-15

361

Gamma-radiation-induced photodarkening in ytterbium-doped silica glasses  

NASA Astrophysics Data System (ADS)

Photodarkening phenomenon in ytterbium (Yb)-doped silica glasses was experimentally investigated by measurements such as electron spin resonance (ESR), X-ray absorption fine-structure (XAFS), and optical transmittance. A predominant increase of Al-oxygen hole center (OHC) was observed for Al-Yb co-doped silica glasses both by the incidence of pump light and by gamma-ray irradiation. It was also recognized that the optical transmission loss similarly increased in both cases. These results indicate that the formation of Al-OHC is the prime cause of the excess loss induced by photodarkening. XAFS measurement indicated that the second-nearest-neighbor atoms around Yb may be related to the mechanism of photodarkening phenomenon.

Arai, T.; Ichii, K.; Tanigawa, S.; Fujimaki, M.

2011-02-01

362

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

NASA Astrophysics Data System (ADS)

Superbroadband near-infrared (NIR) emission covering 1250 to 1680nm wavelength has been obtained in praseodymium (Pr3+) singly doped bismuth gallate glasses. The emission originates from the G41?H53 and D21?G41 transitions at 1330 and 1490nm wavelengths, respectively, and is due to the extremely low phonon energy (˜690cm-1) and the unique ligand field of the glasses. It is shown that the emission line shape can be modified by adjusting the Pr3+ concentration and the energy transfers involved. The results confirm that other than bismuth (Bi), chromium (Cr), nickel (Ni), and other chemical elements, Pr3+ singly doped system is a promising alternative in achieving superbroadband NIR emission.

Zhou, Bo; Yue-Bun Pun, Edwin

2011-08-01

363

Determination of the oxidation state and coordination of a vanadium doped chalcogenide glass  

Microsoft Academic Search

Vanadium doped chalcogenide glass has potential as an active gain medium, particularly at telecommunications wavelengths. This dopant has three spin allowed absorption transitions at 1100, 737 and 578nm, and a spin forbidden absorption transition at 1000nm. X-ray photoelectron spectroscopy indicated the presence of vanadium in a range of oxidation states from V+ to V5+. Excitation of each absorption band resulted

Mark A. Hughes; Richard J. Curry; Daniel W. Hewak

2011-01-01

364

Excitation wavelength dependence of quantum efficiencies of Nd-doped glasses for solar pumped fiber lasers  

Microsoft Academic Search

The quantum efficiencies of the emission from the 4F3\\/2(R) level of Nd doped in tellurite glass were measured with an integrating sphere using natural sunlight(?ns), simulated sunlight (?ns), and 808 nm laser light (?808), respectively. The radiative quantum efficiency (?r) was estimated from the fluorescence lifetime (tauf) and the radiative lifetime calculated by Judd-Ofelt analysis (taur). ?r was almost 100

Takenobu Suzuki; Hiroyuki Kawai; Hiroyuki Nasu; Mark Hughes; Shintaro Mizuno; Kazuo Hasegawa; Hiroshi Ito; Yasutake Ohishi

2010-01-01

365

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

Microsoft Academic Search

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.

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

2004-01-01

366

Non-destructive concentration measurements of erbium-doped ZBLAN fluorozirconate glass  

Microsoft Academic Search

The non-destructive method proposed for the measurements of neodymium concentrations in laser materials has been extended to erbium-doped fluorozirconate glass. It consists of comparing the intensity of a luminescence signal from the rare-earth ions with the intensity of a Raman line from the host matrix, both measured in a single geometry under a microscope. The investigations have been performed in

S. Rogard; A. Bulou; H. Poignant; M. Rousseau

1995-01-01

367

Bi-doped borosilicate glass as sealant for sodium sulfur battery  

Microsoft Academic Search

Bi-doped borosilicate glasses as sealants for sodium sulfur battery are developed. The joining properties involving hermeticity, wetting behavior, bonding strength, thermal shock resistance and corrosion resistance have been systematically investigated. As found, the joints achieve good hermeticity by bulk joining. The wetting behavior and bonding strength are governed by the joining temperature and Bi2O3 content. The higher temperature and higher

Shufeng Song; Zhaoyin Wen; Yu Liu; Xiangwei Wu; Jiu Lin

2011-01-01

368

Upconversion luminescence and mechanisms in Yb 3+-sensitized Tm 3+-doped oxyhalide tellurite glasses  

Microsoft Academic Search

Effect of Yb2O3 content on upconversion luminescence and mechanisms in Yb3+-sensitized Tm3+-doped oxyhalide tellurite glasses were investigated under 980nm excitation. Intense blue and relatively weak red upconversion emission centered at 476 and 649nm corresponding to the transitions 1G4?3H6 and 1G4?3H4 of Tm3+, respectively, are simultaneously observed at room temperature. The results show that upconversion blue and red emission intensities of

Shiqing Xu; Hongping Ma; Dawei Fang; Zaixuan Zhang; Zhonghong Jiang

2006-01-01

369

Structural modifications in Er-Yb doped phosphate glass induced by femtosecond laser waveguide writing  

Microsoft Academic Search

We have systematically studied femtosecond-laser fabrication of optical waveguides in an Er-Yb doped phosphate glass. Waveguides were written using the IMRA America FCPA muJewel D-400 femtosecond fiber laser system with pulse repetition rates ranging from 250 kHz to 2.2 MHz. At every pulse repetition rate a series of waveguides was written while varying scan speeds from 50 mum\\/s to 100

L. B. Fletcher; J. J. Witcher; W. J. Reichman; J. Bovatsek; A. Arai; D. M. Krol

2008-01-01

370

Upconversion luminescence in bismuth-doped germano-silicate glass optical fiber  

NASA Astrophysics Data System (ADS)

We report, for the first time, a broadband upconversion emission (800-1000 nm) in Bi-doped germano-silicate glass optical fibers with excitation in the range of 1515-1585 nm, which can explain the low laser efficiency at wavelengths longer than 1500 nm. The mechanism responsible for the emission is two-step upconversion process. The origin of this upconversion luminescence is discussed and new energy transition schemes are proposed.

Fan, Weiwei; Htein, Lin; Kim, Bok Hyeon; Watekar, Pramod R.; Han, Won-Taek

2013-12-01

371

Magneto-optical investigations of radiation defects in cerium-doped fluorozirconate glasses  

NASA Astrophysics Data System (ADS)

Measurements of the magnetic circular dichroism of the optical absorption (MCDA) on X-irradiated Ce-doped fluorozirconate glass showed an increased paramagnetic band in the range from 300 nm to 700 nm and a new paramagnetic band peaking at 570 nm. Electron paramagnetic resonance (EPR) detected in these MCDA bands yielded two different defect centres having resonances at g=1.90 and g=1.98, respectively.

Schweizer, S.; Assmann, S.; Edgar, A.; Spaeth, J.-M.

2000-05-01

372

Laser emission at 1077 nm in Nd3+-doped calcium aluminosilicate glass  

Microsoft Academic Search

Laser emission at 1077 nm ( 4 F 3\\/2? 4 I 11\\/2) was demonstrated in Nd 3+-doped low silica content calcium aluminosilicate (LSCA) glass under 810-nm pumping by a Ti:sapphire laser. The slope efficiency of the laser emission was found to be 34% with a 20-mW threshold power. The excited-state absorption (ESA) and stimulated emission were measured between 850 and 1520 nm.

D. F. de Sousa; L. A. O. Nunes; J. H. Rohling; M. L. Baesso

2003-01-01

373

Spectroscopic properties of water free Nd 2O 3-doped low silica calcium aluminosilicate glasses  

Microsoft Academic Search

In this work, low silica calcium aluminosilicate glasses (LSCA) doped with different concentrations of Nd2O3 were prepared under vacuum conditions and investigated through spectroscopic measurements. UV, visible and near IR optical absorption spectra, IR luminescence spectra, and fluorescent time decay were measured. Judd–Ofelt model was used in conjunction with these data to calculate intensity parameters (?2,?4 and ?6), emission cross-section,

E. Pecoraro; J. A. Sampaio; L. A. O. Nunes; S. Gama; M. L. Baesso

2000-01-01

374

Fluorescence quantum efficiency in Nd2O3-doped aluminosilicate glasses by multiwavelength thermal lens method  

NASA Astrophysics Data System (ADS)

In this work the multiwavelength thermal lens method is applied to determine the absolute value of fluorescence quantum efficiency of low silica calcium aluminosilicate glasses doped with different concentrations of neodymium dioxide melted under vacuum condition. The experiments were performed using five different excitation wavelengths: 514, 532, 750, 810 and 890 nm. The results were in agreement with those provided by the Judd-Ofelt model.

Astrath, N. G. C.; Rohling, J. H.; Bento, A. C.; Baesso, M. L.; Jacinto, C.; Lima, S. M.; Nunes, L. A. O.; Catunda, T.

2005-06-01

375

Rare earth doping effect on the elastic moduli of low silica calcium aluminosilicate glasses  

Microsoft Academic Search

Elastic moduli (E, G, K, ?) of calcium aluminosilicate glasses with <10 mol% of SiO2 doped with Er2O3 and Yb2O3, melted in air and under vacuum conditions, have been measured using the pulse echo ultrasonic technique. There was a decrease of the elastic properties, <5%, as rare earth oxide replaces Al2O3 from 0.2 to 1.5 mol% (about 8 wt%). The

J. A. Sampaio; M. L. Baesso; S. Gama; A. A. Coelho; J. A. Eiras; I. A. Santos

2002-01-01

376

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

377

Vibrational spectroscopy of OH-related groups in Ce 3+- and Gd 3+-doped silicate glasses  

Microsoft Academic Search

FTIR spectroscopy was applied in the 500–14,000cm?1 range to detect OH vibrational modes (stretching, bending, combination, first and second overtone) in Ce3+- and Gd3+-doped silicate glasses, prepared by means of the sol–gel technique and aimed to applications as scintillators. The presence of OH groups, belonging either to silanol (Si-OH) or to H2O should be limited, since they could cause radiative

A. Baraldi; R. Capelletti; N. Chiodini; C. Mora; R. Scotti; E. Uccellini; A. Vedda

2002-01-01

378

Resonant low-frequency Raman scattering in CdS-doped glasses  

Microsoft Academic Search

Resonant low-frequency Raman scattering experiments performed on CdS-doped glasses reveal two kinds of peaks: the first one is due to the entire nanoparticle distribution and is observed for excitation below the absorption structures of the nanoparticles. The second peak is observed when exciting resonantly the nanoparticles and is due to the resonantly excited nanoparticles only; this is a size selective

L. Saviot; B. Champagnon; E. Duval; A. I. Ekimov

1998-01-01

379

Flame Retardancy Behavior of Zinc Borate  

Microsoft Academic Search

The effect of boron chloride formation from zinc borate in burn ing PVC was elucidated. By thermodynamic calculation, experiment, and infra red spectrum analysis, the conditions for boron halide formation when PVC was burned were addressed. It is found that when boron halide is produced, the B2O3 glass layer is destroyed and boron is volatilized, which is unfavorable to flame

Youming Yang; Xichang Shi; Ruirong Zhao

1999-01-01

380

Spectroscopic characteristics of chromium-doped mullite glass-ceramics  

SciTech Connect

The chromium (3+) ion has been widely used as an optical activator in solid-state, tunable laser materials. High octahedral field-stabilization energy and resistance against both oxidation and reduction minimize the dependence of chromium (3+) on the solid-state host matrix. However, the high sensitivity of electronic structure on crystal field strength makes the appropriate choice of host the condition for success. Characteristics of chromium-doped mullite ceramics are discussed with reference to possible laser applications. Dominant features are attributed to large and inherent spectroscopic inhomogeneity of mullite. The spectroscopic data are analyzed using a generalized McCumber theory. The peak-stimulated emission cross section is 0.54 x 10 to the -20 sq cm. This together with preliminary single-pass measurements, indicate that gain for mullite is about 2.6 times smaller than gain for alexandrite.

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

1988-06-01

381

Electron, hole and exciton self-trapping in germanium doped silica glass from DFT calculations with self-interactions correction  

Microsoft Academic Search

We performed density functional theory (DFT) calculations of electron, hole and exciton self-trapping in germanium doped silica glass to understand the refractive index change in these glasses induced by UV irradiation. The local structure relaxation and excess electron density distribution upon trapping of the above species were calculated. The results show that both trapped exciton and electron are highly localized

Jincheng Du; Louis R. Corrales; Kiril L. Tsemekhman; Eric J. Bylaska

2007-01-01

382

Structure and properties of strontium-doped phosphate-based glasses  

PubMed Central

Owing to similarity in both ionic size and polarity, strontium (Sr2+) is known to behave in a comparable way to calcium (Ca2+), and its role in bone metabolism has been well documented as both anti-resorptive and bone forming. In this study, novel quaternary strontium-doped phosphate-based glasses, containing 1, 3 and 5?mol% SrO, were synthesized and characterized. 31P magic angle spinning (MAS) nuclear magnetic resonance results showed that, as the Sr2+ content is increased in the glasses, there is a slight increase in disproportionation of Q2 phosphorus environments into Q1 and Q3 environments. Moreover, shortening and strengthening of the phosphorus to bridging oxygen distance occurred as obtained from FTIR. The general broadening of the spectral features with Sr2+ content is most probably due to the increased variation of the phosphate–cation bonding interactions caused by the introduction of the third cation. This increased disorder may be the cause of the increased degradation of the Sr-containing glasses relative to the Sr-free glass. As confirmed from elemental analysis, all Sr-containing glasses showed higher Na2O than expected and this also could be accounted for by the higher degradation of these glasses compared with Sr-free glasses. Measurements of surface free energy (SFE) showed that incorporation of strontium had no effect on SFE, and samples had relatively higher fractional polarity, which is not expected to promote high cell activity. From viability studies, however, the incorporation of Sr2+ showed better cellular response than Sr2+-free glasses, but still lower than the positive control. This unfavourable cellular response could be due to the high degradation nature of these glasses and not due to the presence of Sr2+.

Abou Neel, Ensanya A.; Chrzanowski, Wojciech; Pickup, David M.; O'Dell, Luke A.; Mordan, Nicola J.; Newport, Robert J.; Smith, Mark E.; Knowles, Jonathan C.

2008-01-01

383

Effect of Al 3+ on the photoluminescence properties of Ni 2+-doped sol–gel SiO 2 glass  

Microsoft Academic Search

Ni2+-doped SiO2, Al2O3–99SiO2 glasses have been prepared by sol–gel method. The effect of Al3+ on the photoluminescence (PL) properties of Ni2+-doped SiO2 has been studied. Ni2+-doped sol–gel SiO2 glass shows an emission band at 510 nm, which is attributed to the d–d transition 1T2(1D)?3A2(3F) of Ni2+ in octahedral sites. The emission of Ni2+ ions is greatly enhanced by the addition

Chun Feng Song; Meng Kai Lü; Feng Gu; Su Wen Liu; Shu Fen Wang; Dong Xu; Duo Rong Yuan

2003-01-01

384

Study on 2.0 ?m fluorescence of Ho-doped water-free fluorotellurite glasses  

NASA Astrophysics Data System (ADS)

Ho3+-doped water-free fluorotellurite glasses with composition of 60TeO2-30ZnF2-10NaF (mol%, TZNF60) were made by using specially-designed physical and chemical dehydration technique. 2.04 ?m fluorescence (Ho3+: 5I7 ? 5I8) was observed experimentally and presented in this paper: A broad bandwidth of ˜149 nm, large simulated emission cross-section of 7.2 × 10-21 cm2, and the longest reported fluorescence lifetime of ˜10 ms among all the reported Ho3+-doped oxide glasses. Thanks to the absence of OH groups and low phonon energy with the addition fluorides into tellurite oxide glasses, 1.00Ho-TZNF60 glass demonstrates the maximum figure of merit (?em × ?f) of 7.13 × 10-27 m2 s, thus regarded as a promising optical material for the development of 2.0 ?m fiber lasers.

He, Jianli; Zhan, Huan; Zhou, Zhiguang; Zhang, Aidong; Lin, Aoxiang

2013-10-01

385

Optical transitions and visible upconversion in Er3+ doped niobic tellurite glass  

NASA Astrophysics Data System (ADS)

Er3+ doped Nb2O5-TeO2 (NT) glass suitable for developing optical fiber laser and amplifier has been fabricated and characterized. Intense and broad 1.53 ?m infrared fluorescence and visible upconversion luminescence were observed under 975 nm diode laser and 798 nm laser excitation. For 1.53 ?m emission band, the full width at half-maximum is 51 nm, the fluorescence lifetime is 2.6 ms, and the quantum efficiency is ~100%. The maximum emission cross section is 8.52×10-21 cm2 at 1.532 ?m, and is higher than the values in silicon and phosphate glasses. Under 798 nm excitation, efficient 531, 553, and 670 nm upconversion emissions are due to two-photon absorption processes. The ``standardized'' efficiency for the green upconversion light is 9.5×10-4, and this value is comparable to that reported for Er3+/Yb3+ codoped fluoride glasses. Intense visible upconversion fluorescence in Er3+ doped NT glass can be used in color display, undersea communication, and infrared sensor.

Lin, Hai; Meredith, Gerald; Jiang, Shibin; Peng, Xiang; Luo, Tao; Peyghambarian, Nasser; Pun, Edwin Yue-Bun

2003-01-01

386

Enhancement of cells proliferation and control of bioactivity of strontium doped glass  

NASA Astrophysics Data System (ADS)

Bioactivity and chemical reactivity of bioactive glass offer the ability to bond for soft and hard biological tissues. In this work, synthesis was carried out by using melting and rapid quenching. Strontium was introduced as trace element at different contents in the glass matrix, according to its concentration in the bone matrix. This chemical element presents a high interest in the bone metabolism activity. Investigations were conducted on the surface of biomaterials by using in vitro assay after immersion in SBF. Several physico-chemical methods such as SEM, FTIR, NMR, ICP-OES and MTT test were employed to highlight the effects of the Sr. The in vitro experiments showed that after soaking in SBF, the behaviour of pure glass is different compared to glass doped with Sr. NMR analyses showed in the 29Si MAS-NMR that glass matrix undergoes some changes after in vitro assays particularly the emergence of new components attributed to Q 3(OH). The presence of Sr slowed down the bioactivity of glass after immersion in SBF. The non toxic character of compounds was confirmed. Introduction of Sr at 0.1 wt % induce an enhancement of cells at about 14.3%.

Oudadesse, H.; Dietrich, E.; Bui, X. V.; Le Gal, Y.; Pellen, P.; Cathelineau, G.

2011-08-01

387

Electrical conductivity of gamma-irradiated V2O5 doped lithium disilicate glasses doped and their glass-ceramics derivatives  

NASA Astrophysics Data System (ADS)

Some physical properties of the lithium disilicate (Li2Si2O5) glasses doped with different ratios of V2O5 were investigated before and after gamma-rays irradiation. Increasing V2O5 ratio causes remarkable changes in the properties studied. The observed variations in the properties may be correlated with the changes in internal glass network with changes in the chemical composition. Vanadium ions are believed to be present in three possible valence states V3+, V4+ and V5+, and the ratios of these states depend on glass composition. Observed increase in electrical conductivity is assumed to be related to several parameters including the creation of localized state, which increase the charges carrier to conduction band, increase of the number of nonbridging oxygen’s and/ or electron hopping between vanadate ions in different valence states. However, the results indicate that the heat-treatment of amorphous samples accelerate the sequence of formation of lithium metasilicate crystals, causing a decrease in the electrical conductivity. The changes obtained due to gamma-irradiation are correlated to several factors, such as polarization and field strength of the respective cations and to the amount of induced defect centers created upon gamma-irradiation.

All, S. Abd El; Ezz-Eldin, F. M.

2010-01-01

388

Laser and gain parameters at 2.7 ?m of Er 3+-doped oxyfluoride transparent glass–ceramics  

Microsoft Academic Search

The room temperature emission spectrum at about 2.7?m corresponding to the laser transition 4I11\\/2?4I13\\/2 in Er3+-doped nano-scaled transparent oxyfluoride glass–ceramic has been measured and stimulated emission cross-section for the transition has been calculated. The intensity of the transition has been found to be 40 times stronger and lifetime 50 times longer in the glass–ceramics compared to the precursor glass, which

V. K. Tikhomirov; J. Méndez-Ramos; V. D. Rodríguez; D. Furniss; A. B. Seddon

2006-01-01

389

Self-starting KLM Ti:Al2O3 laser using semiconductor-doped glass structures  

Microsoft Academic Search

Summary form only given. We have demonstrated a novel and simple wedge-shaped saturable absorber structure based on commercial semiconductor-doped glass. We have successfully used this colored glass device to mode lock a Ti:sapphire laser and, for the first time to our knowledge, to initiate Kerr lens mode locking (KLM). Semiconductor colored glasses can potentially serve as simple and inexpensive devices

I. P. Bilinsky; B. E. Bouma; J. G. Fujimoto

1998-01-01

390

Assessment of nonradiative relaxation time and characteristic diffusion time of neodymium, erbium and cobalt doped low silica calcium aluminosilicate glasses  

NASA Astrophysics Data System (ADS)

Nonradiative relaxation time ( ?) and characteristic diffusion time (??) of Nd, Er and Co doped low silica calcium aluminosilicate (LSCA) glasses were assessed by means of photoacoustic spectroscopy. The results are interpreted in terms of frequency dependence predicted by the theory of Rosencwaig and Gersho. Whereas ? varied between 7.2 ms and 36 ms, the values of ?? lied between 0.25 ms and 0.7 ms. For the neodymium doped LSCA glass, a decrease in ?? was observed as the ion concentration was increased. The results indicates that rare earth ion acts as network modifier, disrupting the glass lattice.

Mota, L.; Sampaio, J. A.; da Silva, M. G.; Vargas, H.

2011-01-01

391

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

392

Effect of heat-treatment on luminescence and structure of Ag nanoclusters doped oxyfluoride glasses and implication for fiber drawing  

NASA Astrophysics Data System (ADS)

The effect of heat treatment on the structure and luminescence of Ag nanoclusters doped oxyfluoride glasses was studied and the implication for drawing the corresponding fibers doped with luminescent Ag nanoclusters has been proposed. The heat treatment results, first, in condensation of the Ag nanoclusters into larger Ag nanoparticles and loss of Ag luminescence, and further heat treatment results in precipitation of a luminescent-loss nano- and microcrystalline Ag phases onto the surface of the glass. Thus, the oxyfluoride fiber doped with luminescent Ag nanoclusters was pulled from the viscous glass melt and its attenuation loss was 0.19 dB/cm in the red part of the spectrum; i.e. near to the maximum of Ag nanoclusters luminescence band. The nucleation centers for the Ag nanoclusters in oxyfluoride glasses have been suggested to be the fluorine vacancies and their nanoclusters.

Kuznetsov, A. S.; Cuong, Ngo T.; Tikhomirov, V. K.; Jivanescu, M.; Stesmans, A.; Chibotaru, L. F.; Velázquez, J. J.; Rodríguez, V. D.; Kirilenko, D.; van Tendeloo, G.; Moshchalkov, V. V.

2012-02-01

393

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

394

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.

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

2013-11-01

395

A simple low-temperature laser-doping employing phosphosilicate glass and borosilicate glass films for the source and drain formation in poly-Si thin film transistors  

Microsoft Academic Search

A simple low-temperature laser-doping process employing phosphosilicate glass (PSG) and borosilicate glass (BSG) films as dopant sources is proposed in order to fabricate the source and drain in polycrystalline silicon thin film transistors (poly-Si TFTs). The sheet resistance and the dopant depth profile have been successfully controlled by the PH3\\/SiH4 flow ratio, the laser energy density and the number of

Cheon-Hong Kim; Sang-Hoon Jung; Jae-Hong Jeon; Min-Koo Han

2001-01-01

396

Optical spectroscopy and energy transfer in Tm3+-doped metaphosphate laser glasses  

NASA Astrophysics Data System (ADS)

Thulium-doped metaphosphate glasses with four concentrations (0.01, 0.1, 1.0 and 2.0 mol%) of Tm3+ have been prepared and investigated by Raman, absorption and photoluminescence spectral studies. The phonon sideband spectrum has been measured for 1.0 mol% Eu3+-doped metaphosphate glass of the same composition and compared with the Raman spectrum. From vibronic spectra, various bands associated with different structural groups have been identified and assigned. Absorption band positions have been used to simulate the complete energy level diagram for the Tm3+ ion using the model Hamiltonian. Judd-Ofelt parameters have been determined from the absorption bands. Using these parameters, transition probabilities, excited state lifetimes and transition branching ratios have been evaluated. The emission and decay curves of the 1D2 level have been measured for all four glass samples both at RT and 15 K. Lifetimes show a strong quenching for Tm3+ concentrations higher than 0.1 mol%. Fluorescence decay curves of the 1D2 level have been well fitted to the Inokuti-Hirayama model for S = 6, suggesting that the mechanism for energy transfer between Tm3+ ions is of dipole-dipole type.

Babu, P.; Seo, Hyo Jin; Jang, Kyoung Hyuk; Balakrishnaiah, R.; Jayasankar, C. K.; Joshi, A. S.

2005-08-01

397

Microscopic dynamics of the glass transition investigated by time-resolved fluorescence measurements of doped chromophores  

NASA Astrophysics Data System (ADS)

The microscopic dynamics of several monomeric and polymeric glass-forming materials has been investigated by time-resolved fluorescence measurements of doped malachite green molecules in a wide temperature region. For monomers, 1-propanol, propylene glycol, and glycerol, and a polymer without side chains, poly- butadiene, the temperature dependence of nonradiative decay time of doped malachite green molecules behaves in a similar way through the glass-transition region. Besides a kink around the calorimetric glass-transition temperature Tg, another crossover at a critical temperature Tc about 30-50 K above Tg has been clearly observed. This experimental finding is in agreement with the prediction of the mode-coupling theory that a dynamical transition exists well above Tg. On the other hand, for the complex polymers with side chains, poly(vinyl acetate), poly(methyl acrylate), and poly(ethyl methacrylate), the crossover at Tg is less pronounced than those for the monomers and the polymer without side chains. Moreover, although we could not distinguish any singularities above Tg for these complex polymers, we observed another kink below Tg, which may be attributed to the side-chain motions.

Ye, Jing Yong; Hattori, Toshiaki; Nakatsuka, Hiroki; Maruyama, Yoshihiro; Ishikawa, Mitsuru

1997-09-01

398

Optical evaluation on Nd3+-doped phosphate glasses for O-band amplification.  

PubMed

We have fabricated and characterized optically Nd3+-doped phosphate [Li2O-CaO-BaO-Al2O3-La2O3-P2O5 (LCBALP)] glasses for drawing single-mode glass fiber. The 4F3/2?4I13/2 transition emission from the Nd3+ is at the 1.327??m wavelength with a full width at half-maximum of 43?nm, and the spontaneous transition probability and quantum efficiency are calculated to be 1836?s-1 and 52%, respectively. The maximum stimulated emission cross sections for 4F3/2?4I11/2 and 4F3/2?4I13/2 transitions are derived to be 1.82×10(-20)?cm2 and 6.97×10(-21)?cm2, respectively, and the theoretical gain coefficient at the 1.327??m wavelength is evaluated to be 0.182?dB/cm when the fractional factor of the excited neodymium ions equals 0.6, which indicates that Nd3+-doped LCBALP phosphate glasses are potential candidates in developing O-band optical fiber amplifiers. PMID:21343962

Lei, Weihong; Chen, Baojie; Zhang, Xiangling; Pun, Edwin Yun Bun; Lin, Hai

2011-02-20

399

Er3+-doped phosphate glasses with improved gain characteristics for broadband optical amplifiers  

NASA Astrophysics Data System (ADS)

Optical properties of Erbium-doped sodium aluminum telluro-phosphate glasses with compositions of 48P2O5-21Na2O-23Al2O3-(8-x)TeO2-(x)Er2O3 (where x=2-7) were investigated. From the measured optical absorption spectra, Judd-Ofelt (JO) analysis has been carried out to predict radiative properties of doped Er3+ ion luminescent levels. The estimated emission cross sections were found to be more than other commonly available short-length optical amplifier (aluminosilicate) glasses. Relative emission intensity enhancement with the increase of Er3+ ion concentration is observed for the laser transition, 4I13/2?4I15/2 (at 1.53 ?m). Higher emission lifetimes (4.2-6.23 ms), higher quantum efficiencies (44-65%) relative at higher Er3+ ion concentrations, high gain bandwidth and gain per unit length at 1.5 ?m are the most notable features of these glasses for future optical amplifier applications.

Amarnath Reddy, A.; Surendra Babu, S.; Vijaya Prakash, G.

2012-11-01

400

Vibrational spectroscopy of OH-related groups in Ce3+- and Gd3+-doped silicate glasses  

NASA Astrophysics Data System (ADS)

FTIR spectroscopy was applied in the 500-14,000cm-1 range to detect OH vibrational modes (stretching, bending, combination, first and second overtone) in Ce3+- and Gd3+-doped silicate glasses, prepared by means of the sol-gel technique and aimed to applications as scintillators. The presence of OH groups, belonging either to silanol (Si-OH) or to H2O should be limited, since they could cause radiative emission quenching. The samples, doped with Ce3+ or Gd3+ (0.05-3% m.f.), were submitted to thermal treatments at 450°C, 750°C, and 1050°C, to remove water and organic groups for producing a dense glass. A large amount of H2O and Si-OH is still present in samples annealed at 450°C and 750°C, while only a reduced quantity of Si-OH (evaluated as <1% m.f.) is detected after annealing at 1050°C, i.e. in the final dense glasses (for all concentrations of both dopants).

Baraldi, A.; Capelletti, R.; Chiodini, N.; Mora, C.; Scotti, R.; Uccellini, E.; Vedda, A.

2002-06-01

401

Use of CsCl to enhance the glass stability range of tellurite glasses for Er3+ doped optical fiber drawing  

NASA Astrophysics Data System (ADS)

Tellurite glasses are important as a host of Er3+ ions because of their great solubility and because they present broader gain bandwidths than Er3+-doped silica, with promise to increase the bandwidth of communication systems. However, the small glass stability range (GSR) of tellurite glasses compromises the quality of the optical fibers. We show that the addition of CsCl to tellurite glasses can increase their GSR, making it easier to draw good quality optical fibers. CsCl acts as a network modifier in glass systems, weakening the network by forming Te-Cl bonds. We show that the thermal expansion coefficient mismatch is in the right direction for optical fiber fabrication purposes and that the Bi2O3 content can be used to control the refractive index of clad and core glasses. Single-mode and multi-mode Er3+-doped optical fibers were produced by the rod-in-tube method using highly homogeneous TeO2-ZnO-Li2O-Bi2O3-CsCl glasses. Far infrared spectra of the glass samples exhibit absorption bands of the Te-Cl bond.

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

2007-03-01

402

Spectroscopic study of ZnO doped CeO2-PbO-B2O3 glasses  

NASA Astrophysics Data System (ADS)

Glass samples of compositions xZnO-xCeO2-(30-x)PbO-(70-x)B2O3 with x varying from 2% to 10% mole fraction are prepared by the melt quench technique. The structural and optical analysis of glasses is carried out by XRD, FTIR, density and UV-visible spectroscopic measurement techniques. The FTIR spectral analysis indicates that with the addition of ZnO contents in glass network, structural units of BO3 are transformed into BO4. It has been observed in our previous work that band gap decreases from 2.89 to 2.30 eV for CeO2-PbO-B2O3 glasses with cerium content varying from 0% to 10% [Gurinder Pal Singh, Davinder Paul Singh, Physica B 406(3) (2011) 640-644]. With the incorporation of zinc in CeO2-PbO-B2O3 glasses, the optical band gap energy decreases further from 2.38 to 2.03 eV. This causes more compaction of the borate network, which results in an increase of density (3.39-4.02 g/cm3). Transmittance shows that ZnO in glass samples acts as a reducing agent thathelps to convert Ce4+?Ce3+ ions.

Pal Singh, Gurinder; Singh, D. P.

2011-09-01

403

Studies of Er 3+ doped germanate–oxyfluoride and tellurium–germanate–oxyfluoride transparent glass–ceramics  

Microsoft Academic Search

An erbium doped germanate–oxyfluoride glass 60GeO2·20PbO·10PbF2·10CdF2 (GPOF) and a tellurium–germanate–oxyfluoride glass 30TeO2·30GeO2·20PbO·10PbF2·10CdF2 (TGPOF) were prepared in the bulk form. By appropriate heat treatment of the as-prepared glasses above, transparent glass–ceramics were obtained with the formation of ?-PbF2 nanocrystals in the glass matrix confirmed by X-ray diffraction. Optical absorption and photoluminescence measurements were performed on as-prepared glass and glass–ceramics. The luminescence

Z. Pan; A. Ueda; M. Hays; R. Mu; S. H. Morgan

2006-01-01

404

Fluorescence properties and electron paramagnetic resonance studies of {gamma}-irradiated Sm{sup 3+}-doped oxyfluoroborate glasses  

SciTech Connect

The permanent photoinduced valence manipulation of samarium doped oxyfluoroborate glasses as a function of {gamma}-ray irradiation has been investigated using a steady-state fluorescence and electron paramagnetic resonance techniques. An increase in SrF{sub 2} 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 Sm{sup 3+} to Sm{sup 2+} ion. The energy transfer mechanism of induced permanent photoreduction of Sm{sup 3+} to Sm{sup 2+} 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 SrF{sub 2} content in the glass and also with the irradiation dose.

Babu, B. Hari; Ravi Kanth Kumar, V. V. [Department of Physics, Pondicherry University, Kalapet, Puducherry-605 014 (India)

2012-11-01

405

Advanced vapor-doping all-glass double-clad fibers  

NASA Astrophysics Data System (ADS)

We review the advanced attributes of double-clad optical fibers made by the Yb/Al-vapor-doped OVD (outside-vapor-deposition) method developed at Corning Incorporated. The method is characteristically completely synthetic in nature, which allows fiber composition flexibility for both the core and the claddings. Consequently, it has enabled some highly desirable fiber features, such as low-NA core (< 0.05), high-NA clad (> 0.32), high Yb-doping concentration (> 1.2wt %) and ultra-low passive background-loss (~1/~3dB/km for core/innerclad @1310nm), in addition to the unique all-glass double-clad structure by additional composition engineering for the outerclad. Further, a high performance SBS-mitigated double-clad fiber is presented as an example enabled by this versatile OVD methodology.

Wang, Ji; Gray, Stuart; Walton, Donnell T.; Li, Ming-jun; Chen, Xin; Liu, An-ping; Zenteno, Luis A.

2008-02-01

406

Superfluorescence from Yb- and Yb Er-doped phosphotellurite glass fibres  

NASA Astrophysics Data System (ADS)

Short length, air-clad, multimode fibres were fabricated using high concentration Yb- and Yb Er-doped phosphotellurite glass. Superfluorescent light sources are obtained by optically pumping the fibres using a 980 nm laser diode. Ytterbium-doped fibre showed amplified spontaneous emission (ASE) in the 1000 1100 nm wavelength region, whereas Yb Er-codoped fibre in both 1000 1100 nm (due to Yb3+ ions) and 1450 1650 nm (due to Er3+ ions) wavelength regions. The ASE spectra from the fibres are compared for different fibre lengths and pump powers. The observed change in the ASE spectral shape and the shift in peak wavelength with the length of the optical fibre is discussed.

Nandi, P.; Jose, G.

2008-10-01

407

Sm3+ effects in the Tm3+ doped tellurite glass for S-band amplification  

NASA Astrophysics Data System (ADS)

Thulium doped Samarium codoped tellurite-tungstate glasses were produced. Luminescence properties in the infrared region were investigated looking to observe improved properties for S-band amplification in the co doped samples. Thulium is well-known by the 3H4-3F4 radiative transition emitting around ~1.47?m, which is a self-terminating transition in tellurite hosts due the longer lifetime of the lower level in relation to the upper level of this transition. Analysis of absorption and emission spectra showed that we could quench the 3F4 level significantly, what improved the intensity of the emission at 1.49?m. However, the state 3H4 were also quenched due the cross relaxation process due the absorption bands of Sm3+ around 1.5?m.

Belançon, Marcos P.; Ferenz, Julio; Chillcce, Enver; Barbosa, Luis Carlos

2013-02-01

408

Thermal lens study of energy transfer in Yb3+/Tm3+-co-doped glasses  

NASA Astrophysics Data System (ADS)

Energy transfer (ET) and heat generation processes in Yb3+/Tm3+-co-doped low-silica calcium-aluminosilicate glasses were investigated using thermal lens and photoluminescence measurements. Stepwise ET processes from Yb3+ to Tm3+, with excitation at 0.976 ?m, produced efficient emission in the mid-infrared range at around 1.8 ?m, with high fluorescence quantum efficiency (~0.50) and relatively low thermal loading (?0.42). An equation was deduced for the description of the thermal lens results which provided the absolute value of the ET efficiency and optimal Tm3+ concentration that result in population of the 1.8 ?m Tm3+ emitting level. These results suggest that the studied co-doped system would be a promising candidate for the construction of high-power diode-pumped solid-state lasers in the mid-infrared range, which are especially important for the purpose of medical procedures.

Jacinto, C.; Vermelho, Marcos V.; de Araujo, M. T.; Udo, P. T.; Astrath, N. G.; Bento, A. C.; Catunda, T.; Baesso, M. L.

2007-07-01

409

Performance improvement of transparent germanium-gallium-sulfur glass ceramic by gold doping for third-order optical nonlinearities.  

PubMed

Transparent chalcogenide glass ceramics were prepared by thermally treating gold-doped germanium-gallium-sulfur glass. The gold, as nucleating agents, modified the crystallization process of the glass, resulting in the formation of nanocrystals belonging to a single ?-Ga2S3 phase. The crystalline grains increased in number with the treatment duration while their size remained constant, leading to a high infrared transmittance of the glass ceramics. Z-scan measurements revealed the performance improvement of the ?-Ga2S3 nanocrystals to third-order optical nonlinearities. PMID:24150328

Chen, Feifei; Dai, Shixun; Lin, Changgui; Yu, Qiushuang; Zhang, Qinyuan

2013-10-21

410

Correlation of ion dynamics and structure of superionic tellurite glasses  

SciTech Connect

Ion dynamics and structure of a series of superionic AgI-doped silver tellurite glasses have been investigated in this paper. The composition dependence of the dc conductivity and the activation energy of these glasses has been compared with those of AgI-doped silver phosphate and borate glasses. We have observed that the conductivity increases and the activation energy decreases with increase of AgI content and that the tellurite glasses have higher conductivity than those for phosphate or borate glasses. We have analyzed the ac electrical data in the framework of the power law and the electric modulus formalisms. We have established a correlation between the crossover rate of the mobile silver ions and the rearrangement of the structural units in tellurite glasses. The scaling of the conductivity spectra has been used to interpret the temperature and composition dependence of the relaxation dynamics. Analysis of the dielectric relaxation in the framework of modulus formalism indicates an increase in the ion-ion cooperation in the glass compositions with increasing AgI content.

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

2008-01-28

411

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

412

Quantum efficiency measurements on Nd-doped glasses for solar pumped lasers  

Microsoft Academic Search

Nd-doped SiO2–B2O3–Na2O–Al2O3–CaO–ZrO2 glasses were prepared and optical properties such as absorption, lifetime and quantum efficiencies (QEs) of the emission were characterized. QE measurement system with natural sunlight as an excitation source was constructed. The radiative QE (?r) obtained from the lifetime by Judd–Ofelt analysis, directly measured QEs using natural sunlight (?ns), simulated sunlight (?ss) and an 800nm laser (?800) were

Takenobu Suzuki; Hiroyuki Nasu; Mark Hughes; Shintaro Mizuno; Kazuo Hasegawa; Hiroshi Ito; Yasutake Ohishi

2010-01-01

413

Characterization of surface crystallization in Ge-doped graded-index silica glass.  

PubMed

Surface crystallization was induced in Ge-doped silica glass samples from a graded-index optical fiber preform by re-heating them at 1100 degrees C for several hours. X-ray diffraction and second-harmonic generation (SHG) microscopy have been utilized to investigate the crystalline phases formed. Experimental results indicate that the predominant crystalline phase is alpha-cristobalite. The cross-sectional distribution of the crystal particles has also been measured with the SHG microscopy and the result is in good agreement with that from traditional bright field light microscopy. PMID:19474921

An, Honglin; Tang, Ying; McNamara, Pam; Fleming, Simon

2004-03-22

414

Ultraviolet-induced permanent Bragg gratings in cerium-doped ZBLAN glasses or optical fibers.  

PubMed

A holographic method was used to write refractive-index gratings in ZBLAN fluoroziroconate glasses or fibers doped by a Ce concentration of 5000 or 10,000 parts-in-10(6) weight. Direct pumping of the (2)F(5/2)-5d transitions of Ce(3+) ions near 245 nm resulted in a change in the refractive index. The photoinduced change partly recovered on a time scale of several hours at room temperature. The remaining change in the refractive index looked stable on a time scale of a month. This permanent change reaches 2 x 10(-5) at 1560 nm. PMID:19855490

Taunay, T; Niay, P; Bernage, P; Xie, E X; Poignant, H; Boj, S; Delevaque, E; Monerie, M

1994-09-01

415

Energy-transfer processes in Er3+-doped and Er3+,Pr3+-codoped ZBLAN glasses  

Microsoft Academic Search

We present a detailed characterization of energy transfer processes in Er3+-doped and Er3+,Pr3+-codoped ZBLAN bulk glasses. For several Er3+ (0.25–8.75 mol%) and Pr3+ (0.25–1.55 mol%) concentrations, we investigate energy transfer upconversion (ETU) and cross relaxation in Er3+ as well as energy transfer (ET) from Er3+ to the Pr3+ codopant. The measured parameters of ETU from the Er3+ 4I13\\/2 and 4I11\\/2

P. S. Golding; S. D. Jackson; T. A. King; M. Pollnau

2000-01-01

416

Three-photon near-infrared quantum cutting in Tm3+-doped transparent oxyfluoride glass ceramics  

NASA Astrophysics Data System (ADS)

Efficient three-step sequential three-photon near-infrared (NIR) quantum cutting in Tm3+-doped transparent oxyfluoride glass ceramics has been demonstrated, where an absorbed blue photon could be cut into three NIR photons at 1190, 1460, and 1800 nm with quantum yield greater than unity. On the basis of static and dynamic photoemission, monitored excitation, and time-resolved fluorescence spectra, we investigate in detail the underlying optoelectronic mechanism. Further development of an efficient triply-cutting material might open up a path towards ultra-efficient photonic devices, which enables more photons emitted than absorbed in the excitation process.

Yu, D. C.; Zhang, J. P.; Chen, Q. J.; Zhang, W. J.; Yang, Z. M.; Zhang, Q. Y.

2012-10-01

417

Upconversion luminescence in transparent glass ceramics containing ?-PbF 2 nanocrystals doped with erbium  

Microsoft Academic Search

Frequency upconversion luminescence in erbium-doped PbGeO3–PbF2–CdF2-based transparent glass ceramics (TGC) under 980nm infrared excitation is investigated. Upconversion emission signals around 410, 525, 550, 660, and 850nm were generated and identified as due to the 2H9\\/2, 2H11\\/2, 4S3\\/2, and 4F9\\/2 transitions to the 4I15\\/2 ground-state, and 4S3\\/2–4I13\\/2, respectively. The erbium ions excited-state emitting levels were populated via a combination of stepwise

A. S Gouveia-Neto; E. B da Costa; L. A Bueno; S. J. L Ribeiro

2004-01-01

418

Temperature Effects in Up-Conversion Processes of Erbium - Ytterbium Doped Oxyfluoride Silicate Glass  

NASA Astrophysics Data System (ADS)

Er3+ - Yb3+ doped oxyfluoride glass has been synthesized and investigated. It was found that the up-conversion spectrum of the sample excited by a 980 nm laser diode is highly dependent on the temperature of the sample. Using fluorescence intensity ratio technique the green up-conversion emissions at 525 nm and 550 nm were studied in detail in the temperature range 120-600 K. The potential applicability of the obtained results in the field of the temperature sensing is discussed.

Grube, J.; Sarakovskis, A.; Dimitrocenko, L.; Springis, M.

2008-01-01

419

Visible and near infrared photoluminescence of Pr3+ doped oxy-chalcohalide glasses  

NASA Astrophysics Data System (ADS)

We observe the seldom reported near infrared (NIR) emissions at 870 nm (FWHM = 53 nm) and 1037 nm (FWHM = 67 nm) which are in the spectral response region of crystalline silicon photovoltaic solar cells. The emissions are much enhanced with the addition of GeO2, and the possible mechanisms for the photoluminescence spectra evolution are discussed. The decay curves are monitored at both the visible and NIR emissions of Pr3+ doped glasses and lifetimes are calculated using a second-order exponential decay model. Raman spectra are used to characterize some interesting structural evolutions which are responsible for the GeO2 induced luminescence property changes.

Zhang, Ran; Liu, Yinyao; Ren, Jing; Chen, Guorong

2013-05-01

420

Luminescence properties of Nd3+ and Er3+ doped glasses in the VUV region  

NASA Astrophysics Data System (ADS)

We report the vacuum ultraviolet (VUV) spectroscopy of APLF + Nd and APLF + Er glass, with composition 20Al(PO3)3-80LiF + 1NdF3 and + 1ErF3 (in mol%). APLF + Nd and APLF + Er have a dominant fluorescence peak at 185 nm and 168 nm with decay times of 4.5 ns and 5.8 ns, respectively. Fluorescence from APLF + Nd is attributed to 4f25d ? 4f3 transitions in neodymium (Nd) while fluorescence from APLF + Er is due to spin allowed transition in erbium (Er). This is the first report of VUV fluorescence from rare earth ions doped in glass hosts, which could provide the basis for mass production of VUV emitting materials. Our results also suggest the potential of using APLF + Nd and APLF + Er as neutron scintillators during inertial confinement fusion.

Yamanoi, Kohei; Murata, Takahiro; Arikawa, Yasunobu; Nakazato, Tomoharu; Cadatal-Raduban, Marilou; Shimizu, Toshihiko; Sarukura, Nobuhiko; Nakai, Mitsuo; Norimatsu, Takayoshi; Nishimura, Hiroaki; Azechi, Hiroshi; Fujino, Shigeru; Yoshida, Hideki; Yoshikawa, Akira; Satoh, Nakahiro; Kan, Hirofumi

2013-09-01

421

Structural modifications in Er-Yb doped phosphate glass induced by femtosecond laser waveguide writing  

NASA Astrophysics Data System (ADS)

We have systematically studied femtosecond-laser fabrication of optical waveguides in an Er-Yb doped phosphate glass. Waveguides were written using the IMRA America FCPA ?Jewel D-400 femtosecond fiber laser system with pulse repetition rates ranging from 250 kHz to 2.2 MHz. At every pulse repetition rate a series of waveguides was written while varying scan speeds from 50 ?m/s to 100 mm/s and pulse energies from 80 nJ to 320 nJ. The optical quality of the waveguides was evaluated by measuring the waveguide mode profile as well as the optical loss. Laser-induced defects and structural changes in the glass were characterized using confocal fluorescence and Raman microscopy.

Fletcher, L. B.; Witcher, J. J.; Reichman, W. J.; Bovatsek, J.; Arai, A.; Krol, D. M.

2008-03-01

422

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

423

Tunable Room Temperature Second Harmonic Generation in Glasses Doped with CuCI Nanocrystalline Quantum Dots  

SciTech Connect

Two-photon excited emission centered at 379-426 nm in photodarkening borosilicate glass doped with CuCl nanocrystalline quantum dots at room temperature has been observed. The emission is detected in the direction of the fundamental near-infrared beam. Time- and frequency-resolved measurements at room temperature and 77 K indicate that the emission is largely coherent light characteristic of second harmonic generation (SHG). An average conversion efficiency of ~10-10 is obtained for a 2 mm thick sample. The observed SHG can originate in the individual noncentrosymmetric nanocrystals, leading to a bulk-like contribution, and at the nanocrystal-glass interface, leading to a surface contribution. The bulk-like conversion efficiency is estimated using previously reported values of coherence length (5m) and bulk nonlinear susceptibility. This bulk-like conversion efficiency estimate is found to be smaller than the measured value, suggesting a more prominent surface contribution.

Thantu, Napoleon; Schley, Robert Scott; B. L. Justus

2003-05-01

424

Optical Characterization of Tb3+-Doped Gd2O3 Based Scintillating Glasses  

NASA Astrophysics Data System (ADS)

We prepared Tb3+-doped Gd2O3-based oxide glasses by high-temperature melting method and presented their density and optical characterization including transmission, emission and excitation spectra. Dependence of density and luminescence properties on the concentration of Tb3+ and Gd2O3 was also analyzed. The results show that rising Tb3+ ions concentrations would lead to the reduction of distance between Tb3+ ions, the increase of probabilities of energy resonate-transfer and a stronger luminous intensity. In addition, a high Gd2O3 concentration was beneficial to improve the glass samples density, but exerting a negative effect on Tb3+ ions and decreasing the luminous intensity of Tb3+ ions.

Lai, Fei; Zhang, Yue-Pin; Xia, Hai-Ping; Wang, Jin-Hao; He, Wei

2013-09-01

425

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

426

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

427

Relationship between laser-induced gratings and vibrational properties of Eu-doped glasses  

SciTech Connect

Four-wave-mixing techniques have been shown previously to produce permanent refractive index gratings in Eu-doped glasses by resonant excitation of the Eu/sup 3+/ ions. A variety of glass hosts were studied and it was found that permanent holographic gratings could be established in some of these but not in others. We report here an extension of our previous work which includes investigations of new materials, attempts to form gratings with different excitation wavelengths, and a comparison of the Raman and resonant Raman spectra of glasses which do and do not exhibit permanent holographic gratings. It was found that direct excitation into the /sup 5/D/sub 0/ level did not produce permanent gratings. It was also found that glasses which do exhibit permanent gratings have high-frequency vibrational modes which couple strongly to the Eu/sup 3+/ ions. These results help to verify the model proposed previously to explain the origin of the holographic grating in terms of structural changes caused by thermal effects arising from radiationless relaxation through high-frequency local modes.

Durville, F.M.; Behrens, E.G.; Powell, R.C.

1987-03-15

428

Broad-Spectrum Bactericidal Activity of Ag2O-Doped Bioactive Glass  

PubMed Central

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

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

2002-01-01

429

Broadband near-infrared luminescence and energy transfer in Bi singly-doped and Bi/Yb co-doped titanate glasses  

NASA Astrophysics Data System (ADS)

Super-broadband near-infrared (NIR) emission from 1100 nm to 1600 nm is observed in Bi-doped titanate glasses at the excitation of 808 nm laser diode (LD). The effects of Bi content on the optical spectra are investigated. It is also found that the Bi-related emission intensity can be enhanced by Yb3+ co-doping at the excitation of 980 nm LD. It should be ascribed to the energy transfer from Yb3+ to active Bi ions. The energy transfer processes are studied based on the Inokuti-Hirayama (I-H) model, and the energy transfer of electric dipole-dipole interaction is confirmed to be dominant in Bi/Yb co-doped glasses.

Tang, Han; Xia, Hai-ping

2012-11-01

430

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

Microsoft Academic Search

Homogeneous ZnSe nanocrystals doped SiO2 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 4–10nm 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

Haiyan Hao; Xi Yao; Minqiang Wang

2007-01-01

431

Mixed Former Effect: A Kind of Composition Adjusting Method of Er-Doped Glass for Broadband Amplification  

NASA Astrophysics Data System (ADS)

A compositional adjusting method called the mixed former effect is proposed to improve effectively optical properties such as the emission cross section, the fluorescence full width at half maximum (FWHM) and the lifetime of the 4I13/2 level of Er-doped glass. A kind of Er-doped bismuth-based glass illustrated high emission cross section (?ep = 0.66-0.90 pm2), large fluorescence FWHM (68-85 nm), and relatively long lifetime of the 4I13/2 level (?m = 1.6-4.3 ms) using this method. A comparison of spectroscopic parameters shows that bismuth-based glass is much better for broadband amplifiers than other glass hosts.

Yang, Jian-Hu; Dai, Shi-Xun; Wen, Lei; Liu, Zhu-Ping; Hu, Li-Li; Jiang, Zhong-Hong

2002-10-01

432

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

433

Time-resolved studies of emission properties of cerium-doped fluoro-hafnate glasses under VUV synchrotron radiation excitation  

NASA Astrophysics Data System (ADS)

The emission and excitation spectra as well as the decay kinetics of cerium-doped fluoro-hafnate glasses of various compositions have been studied using vacuum ultraviolet synchrotron radiation excitation. It has been found that iso-valent modifications of the glass composition do not strongly affect the decay kinetics of cerium emission while two-valent oxygen ions create additional quenching centres leading to a decrease of the light yield. It has been shown that the quenching of Ce emission in cerium-doped fluoro-hafnate glasses starts with a process of impact excitation of cerium emission centres. The results show that the dominant mechanism of energy transfer from the matrix to cerium emission centres in fluoride glasses is different for the 315 nm band and the 400 nm band.

Devitsin, E. G.; Kirikova, N. Yu.; Kozlov, V. A.; Makhov, V. N.; Potashov, S. Yu.; Dmitruk, L. N.; Terekhin, M. A.; Munro, I. H.; Mythen, C.; Shaw, D. A.; Bell, K. W.; Brown, R. M.; Flower, P. S.; Jeffreys, P. W.; Parker, J. M.

1998-02-01

434

Structural and spectroscopic studies on Er3+ doped boro-tellurite glasses  

NASA Astrophysics Data System (ADS)

Er3+ doped boro-tellurite glasses with the chemical composition (69-x)B2O3-xTeO2-15MgO-15K2O-1Er2O3 (where x=0, 10, 20, 30 and 40 wt%) have been prepared and their structural and spectroscopic behavior were studied and reported. The varying tellurium dioxide content in the host matrix that results, changes in structural and spectroscopic behavior around Er3+ ions are explored through XRD, FTIR, UV-VIS-NIR and luminescence measurements. The XRD pattern confirms the amorphous nature of the prepared glasses and the FTIR spectra explore the fundamental groups and the local structural units in the prepared boro-tellurite glasses. The bonding parameters (?¯ and ?) have been calculated from the observed band positions of the absorption spectra to claim the ionic/covalent nature of the prepared glasses. The Judd-Ofelt (JO) intensity parameters ?? (?=2, 4 and 6) were determined through experimental and calculated oscillator strengths obtained from the absorption spectra and their results are studied and compared with reported literature. The variation in the JO parameters ?? (?=2, 4 and 6) with the change in chemical composition have been discussed in detail. The JO parameters have also been used to derive the important radiative properties like transition probability (A), branching ratio (?R) and peak stimulated emission cross-section (?PE) for the excited state transitions 2H9/2?4I15/2 and 2H11/2 and 4S3/2?4I15/2 of the Er3+ ions and the results were studied and reported. Using Davis and Mott theory, optical band gap energy (Eopt) values for the direct and indirect allowed transitions have been calculated and discussed along with the Urbach energy values for the prepared Er3+ doped boro-tellurite glasses in the present study. The optical properties of the prepared glasses with the change in tellurium dioxide have been studied and compared with similar results.

Selvaraju, K.; Marimuthu, K.

2012-04-01

435

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

436

Influence of Er{sup 3+} doping on microstructure of oxyfluoride glass-ceramics  

SciTech Connect

Oxyfluoride glasses with composition of 45SiO{sub 2}.20Al{sub 2}O{sub 3}.30PbF{sub 2}.5ZnF{sub 2} by molar ratio with a high stability against crystallization have been obtained by melt quenching. After doping with x (x = 1, 2, 4) mol% of Er{sup 3+} transparent or translucent glass-ceramics could be formed. The structural transformations of these materials were investigated by thermal analysis, X-ray diffraction (XRD), transmission electron microscopy (TEM) and energy dispersive X-ray spectroscopy (EDS). Spherical polycrystalline aggregates comprised of many nanosized and randomly oriented {beta}-PbF{sub 2} grains were embedded separately among glassy matrix. On heating these nanosized grains merge with their neighbors to form bigger single crystals in a way like Ostwald ripening. The size modification of polycrystalline aggregates in the samples was found to be dependent on Er{sup 3+} doping.

Bao Feng [State Key Laboratory of Structural Chemistry, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences, Fuzhou, Fujian 350002 (China); Wang Yuansheng [State Key Laboratory of Structural Chemistry, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences, Fuzhou, Fujian 350002 (China)]. E-mail: yswang@fjirsm.ac.cn; Hu Zhongjian [State Key Laboratory of Structural Chemistry, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences, Fuzhou, Fujian 350002 (China)

2005-10-06

437

Effect of borate glass composition on its conversion to hydroxyapatite and on the proliferation of MC3T3-E1 cells.  

PubMed

Glasses containing varying amounts of B(2)O(3) were prepared by partially or fully replacing the SiO(2) in silicate 45S5 bioactive glass with B(2)O(3). The effects of the B(2)O(3) content of the glass on its conversion to hydroxyapatite (HA) and on the proliferation of MC3T3-E1 cells were investigated in vitro. Conversion of the glasses to HA in dilute (20 mM) K(2)HPO(4) solution was monitored using weight loss and pH measurements. Proliferation of MC3T3-E1 cells was determined qualitatively by assay of cell density at the glass interface after incubation for 1 day and 3 days, and quantitatively by fluorescent measurements of total DNA in cultures incubated for 4 days. Higher B(2)O(3) content of the glass increased the conversion rate to HA, but also resulted in a greater inhibition of cell proliferation under static culture conditions. For a given mass of glass in the culture medium, the inhibition of cell proliferation was alleviated by using glasses with lower B(2)O(3) content, by incubating the cell cultures under dynamic rather than static conditions, or by partially converting the glass to HA prior to cell culture. PMID:18306284

Brown, Roger F; Rahaman, Mohamed N; Dwilewicz, Agatha B; Huang, Wenhai; Day, Delbert E; Li, Yadong; Bal, B Sonny

2009-02-01

438

Frequency Dependent Conductivity of PbI2 Doped Silver Boro-Vanadate Super Ionic Glass System  

NASA Astrophysics Data System (ADS)

AC Conductivity measurements have been used to study the transport properties of PbI2 doped silver boro-vanadate glasses prepared by melt quenching technique. The samples are characterized by XRD and DSC measurements. A correlation between R?, the decoupling index and ?dc has been observed. The observed conductivity values suggest enhancement in conductivity by the introduction of PbI2 salt in the host glass matrix.

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

2010-12-01

439

LETTER TO THE EDITOR: Blue lasing from a stilbenoid-compound-doped glass-clad polymer optical fibre  

Microsoft Academic Search

We report on blue lasing from a step index glass-clad polymer optical fibre doped with a novel fluorescent stilbenoid compound, 1, 4-bis(4-diphenylamino-styryl)-benzene. The compound has a very high quantum yield of 0.85 in polystyrene and a relatively large Stokes shift of 50 nm. The glass-clad fibre is fabricated by drawing a liquid solution of polystyrene containing the compound along into

Takeyuki Kobayashi; Werner J. Blau; Hartwig Tillmann; Hans-Heinrich Hörhold

2002-01-01

440

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

PubMed

The spectroscopic properties and thermal stability of Er3+-doped Bi2O3-B2O3-Ga2O3 glasses are investigated experimentally. The effect of Ga2O3 content on absorption spectra, the Judd-Ofelt parameters Omega t (t=2, 4, 6), fluorescence spectra and the lifetimes of Er3+:4I 13/2 level are also investigated, and the stimulated emission cross-section is calculated from McCumber theory. With the increasing of Ga2O3 content in the glass composition, the Omega t (t=2, 4, 6) parameters, fluorescence full width at half maximum (FWHM) and the 4I 13/2 lifetimes of Er3+ first increase, reach its maximum at Ga2O3=8 mol.%, and then decrease. The results show that Er3+-doped 50Bi2O3-42B2O3-8Ga2O3 glass has the broadest FWHM (81nm) and large stimulated emission cross-section (1.03 x1 0(-20)cm2) in these glass samples. Compared with other glass hosts, the gain bandwidth properties of Er+3-doped Bi2O3-B2O3-Ga2O3 glass is better than tellurite, silicate, phosphate and germante glasses. In addition, the lifetime of 4I 13/2 level of Er(3+) in bismuth-based glass, compared with those in other glasses, is relative low due to the high-phonon energy of the B-O bond, the large refractive index of the host and the existence of OH* in the glass. At the same time, the glass thermal stability is improved in which the substitution of Ga2O3 for B2O3 strengthens the network structure. The suitability of bismuth-based glass as a host for a Er3+-doped broadband amplifier and its advantages over other glass hosts are also discussed. PMID:17350330

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

2006-12-22

441

Energy level decay and excited state absorption processes in dysprosium-doped fluoride glass  

NASA Astrophysics Data System (ADS)

The primary excited state decay processes relating to the 6H13/2-->6H15/2~3 ?m laser transition in singly Dy3+-doped fluoride (ZBLAN) glass have been investigated in detail using time-resolved fluorescence spectroscopy. Selective laser excitation of the 6F9/2, 6H7/2 energy levels at 1125 nm and 6F11/2, 6H9/2 energy levels at 1358 nm established that the energy levels above the 6H11/2 level, excluding the 4F9/2 level, are entirely quenched by multiphonon emission in ZBLAN glass. The 6H11/2 and 6H13/2 energy levels emit luminescence with peaks at ~1700 and ~2880 nm, respectively, but at low quantum (luminescence) efficiencies. The quantum efficiency of the 6H11/2 level and 6H13/2 level is ~9×10-5 and ~1.3×10-2, respectively, for [Dy3+]=0.5 mol % based on calculations of the radiative lifetimes using the Judd-Ofelt theory. Excited state absorption (ESA) was detected by monitoring the rise time of the 1700 nm luminescence after tuning the probe wavelength across the spectral range from 1100 to 1400 nm. As a result of nonradiative decay of the higher excited states, ESA contributes to the heating of ~3 ?m fiber lasers based on Dy3+-doped fluoride glass. For [Dy3+] up to 4 mol %, we found no evidence of energy transfer processes between Dy3+ ions that influence the decay characteristics of the 6H11/2 and 6H13/2 energy levels.

Gomes, Laércio; Librantz, André Felipe Henriques; Jackson, Stuart D.

2010-03-01

442

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

443

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 tun