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1

Spectroscopic studies of tantalum doped borate glasses  

NASA Astrophysics Data System (ADS)

Glasses with formula 30Li2O 60B2O3xTa2O5 (10-x) Bi2O3 for x=0, 2, 4, 6 and 8 were prepared via normal melt quenching technique and characterized by refractive index and MDSC. Refractive index (?) and glass transition temperature (Tg) are found to increase with increase in dopant concentration. Impedance spectra of the samples were recorded in the frequency range 100 Hz-5 MHz in the temperature range 175-275 °C. The plots are typical of those recorded for disordered systems. Conductivities and relaxation times are found to follow Arrhenius type of relation and activation energies are calculated. Optical absorption spectra were recorded in the wavelength range 200-900 nm range from which cutoff wavelength (?c) and optical band gap energy (Eg) are evaluated. ?c is found to decrease while Eg to increase with increase in composition. FTIR spectra of the samples were recorded in the frequency range 400-1500 cm-1 which exhibit characteristic bands corresponding to BO3, BO4 stretching vibrations and BO bending vibration. Tightening of the structure is indicated by increase in the vibration of BO3 at the cost of BO4 for 8 mol% of Ta2O5. This is in support of the highest value of Tg for this sample among the series. Raman spectra of the samples were recorded in the frequency range 200-1200 cm-1. With successive addition of Ta2O5, increase in the vibration of Ta-O groups TaO6 groups to be responsible for observed increase in ? and Tg. An attempt is made to prepare tantalum doped borate glasses and study them by spectroscopic techniques.

Sharada, M.; Suresh Babu, D.

2012-10-01

2

Synthesis and structural studies of praseodymium doped silver borate glasses  

NASA Astrophysics Data System (ADS)

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

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

2013-02-01

3

Synthesis and structural studies of praseodymium doped silver borate glasses  

SciTech Connect

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

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

2013-02-05

4

Elastic properties of Li+ doped lead zinc borate glasses  

NASA Astrophysics Data System (ADS)

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

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

2014-04-01

5

Structural studies of lead lithium borate glasses doped with silver oxide  

Microsoft Academic Search

Silver oxide doped lead lithium borate (LLB) glasses have been prepared and characterized. Structural and composition characterization were accessed by XRD, FTIR, Raman, SEM and EDS. Results from FTIR and Raman spectra indicate that Ag2O acts as a network modifier even at small quantities by converting three coordinated to four coordinated boron atoms. Other physical properties, such as density, molar

João Coelho; Cristina Freire; N. Sooraj Hussain

6

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

NASA Astrophysics Data System (ADS)

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

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

2014-12-01

7

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

NASA Astrophysics Data System (ADS)

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

Sathish, M.; Eraiah, B.

2013-06-01

8

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

PubMed

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

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

2012-02-01

9

Structural studies of lead lithium borate glasses doped with silver oxide  

NASA Astrophysics Data System (ADS)

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

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

2012-02-01

10

Physical, structural, and luminescence studies of Nd3+ doped MgO-ZnO borate glass  

NASA Astrophysics Data System (ADS)

A series of borate glass of the system xNd2O3-5MgO-20ZnO-(75 - x)B2O3, where x = 0.5, 1.0,1.5, 2.0, and 2.5 was successfully fabricated using melt quench method. The properties of the glass were characterized using X-ray diffraction (XRD), Fourier transform infrared (FTIR), absorption and luminescence spectra. The upconversion properties of Nd3+ doped borate glass were observed by using 574 nm excitation wavelength corresponding to 4 I 15/2 ? 2 H 114/2 transition. The emission bands centered at 460, 500 and 620 nm which corresponding to the Nd3+ transitions, 4 F 7/2 ? 4 I 15/2, 2 H 11/2 ? 4 I 15/2, and 4 F 9/2 ? 4 I 15/2 respectively were observed at room temperature. The presence of Nd3+ in borate based glass could intensify the upconversion luminescence spectra as it can potentially be used as host materials for upconversion lasers.

Razali, W. A. W.; Azman, K.; Hashim, S.; Alajerami, Yasser Saleh Mustafa; Syamsyir, S. A.; Mardhiah, A.; Ridzwan, M. H. J.

2013-11-01

11

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

NASA Astrophysics Data System (ADS)

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

Wen, Hongli; Tanner, Peter A.

2011-09-01

12

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

NASA Astrophysics Data System (ADS)

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

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

2013-09-01

13

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

14

Elastic properties of silver borate glasses doped with praseodymium oxide  

SciTech Connect

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

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

2014-04-24

15

Optical properties of Nd3+ doped bismuth zinc borate glasses  

NASA Astrophysics Data System (ADS)

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

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

2014-03-01

16

Optical properties of Nd3+ doped bismuth zinc borate glasses.  

PubMed

Glasses with compositions of (100-x) (Bi2ZnOB2O6) -x Nd2O3 (where x=0.1, 0.3, 0.5, 1 and 2 mol%) were prepared by melt quenching method and characterized through optical absorption, emission and decay curve measurements. Optical absorption spectra have been analyzed using Judd-Ofelt theory. The emission spectra exhibit three peaks at 919, 1063 and 1337 nm corresponding to (4)F3/2 to (4)I9/2, (4)I11/2 and (4)I13/2 transitions in the near infrared region. The emission intensity of the (4)F3/2 to (4)I11/2 transition increases with increase of Nd(3+) concentration up to 1 mol% and then concentration quenching is observed for 2 mol% of Nd(3+) concentration. The lifetimes for the (4)F3/2 level are found to decrease with increase in Nd2O3 concentration in the glasses. The decay curves of the glass up to 0.3 mol% of Nd(3+) exhibit single exponential nature and thereafter the curves become nonexponential nature (0.5, 1 and 2 mol%). The nonexponential curve has been fitted to the Inokuti-Hirayama model to understand the nature of energy transfer process. PMID:24326260

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

2014-03-25

17

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

NASA Astrophysics Data System (ADS)

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

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

2014-10-01

18

The Preparation and Characterization of Nd{sub 2}O{sub 3} Doped Borate Glass  

SciTech Connect

The Nd{sup 3+} doped borate glass of Nd{sub 2}O{sub 3}-MgO-ZnO-B{sub 2}O{sub 3} glass system is successfully been prepared by melt-quenched technique. Batches of 15g were prepared from certified reagent grades of B{sub 2}O{sub 3}(99.95% purity), MgO (97%), ZnO (98% purity), and Nd{sub 2}O{sub 3}(99.99%). The measured glass densities are found varies from 5683.2 kgm{sup -3} to 5724.0 kgm{sup -3}. The increment in density implies that an addition of Nd{sub 2}O{sub 3} with higher atomic masses than B{sub 2}O{sub 3} tend to increase the packing density of the glass structures since the atomic masses of B{sub 2}O{sub 3} and Nd{sub 2}O{sub 3} are 69.62 and 336.42 respectively. From the density values obtained, the molar volume of glasses was calculated. From the results, it is found that the molar volume of these glasses decreases slightly from 22.50 cm{sup 3} to 27.54 cm{sup 3} with respect to Nd{sub 2}O{sub 3} content.

Razali, Wan Aizuddin Wan; Kasim, Azman; Mohamed, Ruziana [Optical Material Group, Universiti Teknologi MARA Pahang, Bandar Jengka, Pahang (Malaysia)

2010-07-07

19

The Preparation and Characterization of Nd2O3 Doped Borate Glass  

NASA Astrophysics Data System (ADS)

The Nd3+ doped borate glass of Nd2O3-MgO-ZnO-B2O3 glass system is successfully been prepared by melt-quenched technique. Batches of 15g were prepared from certified reagent grades of B2O3 (99.95% purity), MgO (97%), ZnO (98% purity), and Nd2O3 (99.99%). The measured glass densities are found varies from 5683.2 kgm-3 to 5724.0 kgm-3. The increment in density implies that an addition of Nd2O3 with higher atomic masses than B2O3 tend to increase the packing density of the glass structures since the atomic masses of B2O3 and Nd2O3 are 69.62 and 336.42 respectively. From the density values obtained, the molar volume of glasses was calculated. From the results, it is found that the molar volume of these glasses decreases slightly from 22.50 cm3 to 27.54 cm3 with respect to Nd2O3 content.

Razali, Wan Aizuddin Wan; Kasim, Azman; Mohamed, Ruziana

2010-07-01

20

Spectroscopic investigations of Nd3+ doped flouro- and chloro-borate glasses.  

PubMed

Spectroscopic and physical properties of Nd3+ doped sodium lead flouro- and chloro-borate glasses of the type 20NaX-30PbO-49.5B2O3-0.5Nd2O3 (X=F and Cl) have been investigated. Optical absorption spectra have been used to determine the Slater Condon (F2, F4, and F6), spin orbit xi4f and Racah parameters (E1, E2, and E3). The oscillator strengths and the intensity parameters Omega2, Omega4 and Omega6 have been determined by the Judd-Ofelt theory, which in turn provide the radiative transition probability (A), total transition probability (A(T)), radiative lifetime (tauR) and branching ratio (beta) for the fluorescent level 4F3/2. The lasing efficiency of the prepared glasses has been characterized by the spectroscopic quality factor (Omega4/Omega6), the value of which is in the range of 0.2-1.5, typical for Nd3+ in different laser hosts. Nephelauxetic effect results in a red shift in the energy levels of Nd3+ for chloroborate glass. The radiative transition probability of the potential lasing transition 4F3/2-->4I11/2 of Nd3+ ions is found to be higher for flouroborate as compared to chloroborate glass. PMID:18068421

Mohan, Shaweta; Thind, Kulwant Singh; Sharma, Gopi; Gerward, Leif

2008-10-01

21

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

NASA Astrophysics Data System (ADS)

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

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

2014-07-01

22

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

PubMed

Characteristics of lithium potassium borate glasses with various copper concentrations are reported. The glasses were prepared by the melt quenching method and irradiated with photons to doses in the 0.5-4.0 Gy range. Glowing curves, dose response curves, reproducibility of the response, dose threshold, thermal fading and optical bleaching were studied. PMID:24681645

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

2014-08-01

23

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

PubMed

UV-visible and FT infrared spectra were measured for prepared samples before and after gamma irradiation. Base undoped barium borate glass of the basic composition (BaO 40%-B2O3 60mol.%) reveals strong charge transfer UV absorption bands which are related to unavoidable trace iron impurities (Fe(3+)) within the chemical raw materials. 3d transition metal (TM)-doped glasses exhibit extra characteristic absorption bands due to each TM in its specific valence or coordinate state. The optical spectra show that TM ions favor generally the presence in the high valence or tetrahedral coordination state in barium borate host glass. Infrared absorption bands of all prepared glasses reveal the appearance of both triangular BO3 units and tetrahedral BO4 units within their characteristic vibrational modes and the TM-ions cause minor effects because of the low doping level introduced (0.2%). Gamma irradiation of the undoped barium borate glass increases the intensity of the UV absorption together with the generation of an induced broad visible band at about 580nm. These changes are correlated with suggested photochemical reactions of trace iron impurities together with the generation of positive hole center (BHC or OHC) within the visible region through generated electrons and positive holes during the irradiation process. PMID:24983922

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

2014-12-10

24

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

NASA Astrophysics Data System (ADS)

UV-visible and FT infrared spectra were measured for prepared samples before and after gamma irradiation. Base undoped barium borate glass of the basic composition (BaO 40%-B2O3 60 mol.%) reveals strong charge transfer UV absorption bands which are related to unavoidable trace iron impurities (Fe3+) within the chemical raw materials. 3d transition metal (TM)-doped glasses exhibit extra characteristic absorption bands due to each TM in its specific valence or coordinate state. The optical spectra show that TM ions favor generally the presence in the high valence or tetrahedral coordination state in barium borate host glass. Infrared absorption bands of all prepared glasses reveal the appearance of both triangular BO3 units and tetrahedral BO4 units within their characteristic vibrational modes and the TM-ions cause minor effects because of the low doping level introduced (0.2%). Gamma irradiation of the undoped barium borate glass increases the intensity of the UV absorption together with the generation of an induced broad visible band at about 580 nm. These changes are correlated with suggested photochemical reactions of trace iron impurities together with the generation of positive hole center (BHC or OHC) within the visible region through generated electrons and positive holes during the irradiation process.

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

2014-12-01

25

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

NASA Astrophysics Data System (ADS)

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

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

2015-04-01

26

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

NASA Astrophysics Data System (ADS)

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

Ottomeyer, Megan

27

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

SciTech Connect

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

Abdel-Baki, Manal [Glass Department, National Research Centre, Dokki 12311 Giza (Egypt); Abdel-Wahab, Fathy A.; El-Diasty, Fouad [Physics Department, Faculty of Science, Ain Shams University, Abbasia, 11566 Cairo (Egypt)

2012-04-01

28

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

NASA Astrophysics Data System (ADS)

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

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

2014-09-01

29

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

PubMed

Lithium potassium borate (LKB) glasses co-doped with TiO2 and MgO were prepared using the melt quenching technique. The glasses were cut into transparent chips and exposed to gamma rays of (60)Co to study their thermoluminescence (TL) properties. The TL glow curve of the Ti-doped material featured a single prominent peak at 230 °C. Additional incorporation of MgO as a co-activator enhanced the TL intensity threefold. LKB:Ti,Mg is a low-Z material (Z(eff)=8.89) with slow signal fading. Its radiation sensitivity is 12 times lower that the sensitivity of TLD-100. The dose response is linear at doses up to 10(3) Gy. The trap parameters, such as the kinetics order, activation energy, and frequency factor, which are related to the glow peak, were determined using TolAnal software. PMID:24929526

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

2014-09-01

30

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

SciTech Connect

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

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

2011-10-15

31

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

NASA Astrophysics Data System (ADS)

The present paper aims at reporting the optical absorption and emission properties of Dy3+ doped alkali (Li, Na, K) and mixed alkali (Li-Na, Li-K, Na-K) heavy metal borate glasses. For these glasses X-ray diffraction (XRD), differential scanning calorimetry (DSC), optical absorption, emission and lifetime decay measurements were carried out. Glass transition temperatures are obtained from the DSC spectra. Judd-Ofelt theory has been used to derive the spectral intensities (f), Judd-Ofelt intensity parameters (?2, ?4 and ?6) and certain radiative properties. Using the Judd-Ofelt intensity parameters, radiative lifetimes (?R), branching ratios (?), integrated absorption cross-sections (?) and emission cross-sections (?P) were obtained. The variations in these parameters with the variation of glass matrix are discussed in detail. The decay lifetime of the 4F9/2 level has been measured from the decay profiles and compared with calculated lifetimes. From the emission spectra, chromacity color coordinates are calculated and indicated the white light emission for potassium glass matrices. It was observed that among various glass matrices, potassium glass matrix has exhibited large emission cross-section for 6F9/2 ? 6H13/2 transition.

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

2013-06-01

32

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

33

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

NASA Astrophysics Data System (ADS)

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

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

2013-07-01

34

Spectroscopic properties and luminescence behaviour of europium doped lithium borate glasses  

NASA Astrophysics Data System (ADS)

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

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

2014-12-01

35

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

36

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

NASA Astrophysics Data System (ADS)

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

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

2011-03-01

37

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

PubMed

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

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

2011-03-28

38

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

39

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

40

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

SciTech Connect

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

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

2011-08-01

41

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

PubMed

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

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

2014-08-14

42

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

NASA Astrophysics Data System (ADS)

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

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

2007-02-01

43

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

Microsoft Academic Search

We have investigated the effect of gamma irradiation on the optical properties of Li2O B2O3 containing two concentrations (0.2 or 0.5 g) of each one of the following transition metals, V, Mn, Fe or Ni oxide glass samples. We studied the impacts of gamma irradiation in terms of the mechanism by which radiation-induced defects are generated. A resolution of the

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

2006-01-01

44

Structural and physical properties of vanadium doped copper bismuth borate glasses  

SciTech Connect

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

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

2013-02-05

45

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

46

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

PubMed

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

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

2015-06-01

47

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

NASA Astrophysics Data System (ADS)

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

Fatokun, Stephen O.

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

Effect of MoO3 on electron paramagnetic resonance spectra, optical spectra and dc conductivity of vanadyl ion doped alkali molybdo-borate glasses  

NASA Astrophysics Data System (ADS)

Alkali molybdo-borate glasses having composition xMoO3·(30 - x)M2O·70B2O3 and xMoO3·(70 - x)B2O3·30M2O (M = Li, Na, K) with 0 ? x ? 15 (mol%) doped with 2.0 mol% of V2O5 have been prepared in order to study the influence of MoO3 on electrical conductivity, electron paramagnetic resonance (EPR) and optical spectra. From EPR studies it is observed that V4+ ions in these samples exist as VO2+ ions in octahedral coordination with a tetragonal compression and belong to C4V symmetry. The tetragonal nature and octahedral symmetry of V4+O6 complex increase as well as decrease depending upon the composition of glasses with increase in MoO3 but 3dxy orbit of unpaired electron in the VO2+ ion expands in all the glasses. The decrease in optical band gap suggests that there is an increase in the concentration of non-bridging oxygen's. From the study of optical transmission spectra it is observed that for all the glasses the degree of covalency of the ?-bonding decreases with increase in MoO3 content and the degree of covalency of the ?-bonding also varies. These results based on optical spectroscopy are in agreement with EPR findings. It is found that dc conductivity decreases and activation energy increases with increase in MoO3:M2O (M = Li, Na, K) ratio in MoO3·M2O·B2O3 glasses, whereas the conductivity increases and activation energy decreases with increase in MoO3:B2O3 ratio in xMoO3·B2O3·M2O glasses, which is governed by the increase in nonbridging oxygen's. The variation in theoretical optical basicity, ?th is also studied.

Agarwal, A.; Khasa, S.; Seth, V. P.; Sanghi, S.; Arora, M.

2014-02-01

50

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

SciTech Connect

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

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

2013-02-05

51

Structural properties of Zinc Lithium borate glass  

NASA Astrophysics Data System (ADS)

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

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

2014-09-01

52

Interfacial reactions between titanium and borate glass  

SciTech Connect

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

Brow, R.K. [Sandia National Labs., Albuquerque, NM (United States); Saha, S.K.; Goldstein, J.I. [Lehigh Univ., Bethlehem, PA (United States). Dept. of Materials Science

1992-12-31

53

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

NASA Astrophysics Data System (ADS)

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

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

2014-05-01

54

UNCORRECTEDPROOF 2 Optical properties of bismuth borate glasses  

E-print Network

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

Osnabrück, Universität

55

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

NASA Astrophysics Data System (ADS)

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

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

2014-10-01

56

Impact of vanadium ions in barium borate glass  

NASA Astrophysics Data System (ADS)

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

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

2015-02-01

57

Impact of vanadium ions in barium borate glass.  

PubMed

Combined optical and infrared spectral measurements of prepared barium borate glasses containing different concentrations of V2O5 were carried out. Vanadium containing glasses exhibit extended UV-visible (UV/Vis.) bands when compared with base binary borate glass. UV/Vis. spectrum shows the presence of an unsymmetrical strong UV broad band centered at 214 nm attributed to the presence of unavoidable trace iron impurities within the raw materials used for the preparation of such glass. The calculated direct and indirect optical band gaps are found to decrease with increasing the vanadium content (2.9:137 for indirect and 3.99:2.01 for direct transition). This change was discussed in terms of structural changes in the glass network. Infrared absorption spectra of the glasses reveal the appearance of both triangular and tetrahedral borate units. Electron spin resonance analyses indicate the presence of unpaired species in sufficient quantity to be identified and to confirm the spectral data. PMID:25194319

Abdelghany, A M; Hammad, Ahmed H

2015-02-25

58

The leaching behavior of borate waste glass SL-1  

SciTech Connect

Vitrification is an attractive approach for treatment of the borate waste from nuclear power plants. SL-1 glass is a suitable borosilicate glass form to solidify the borate waste containing relatively high quantities of B and Na. The leaching behavior of SL-1 glass in deionized water has been investigated. Compared to the HLW-glass, the network structure of SL-1 glass is weak. It was found that the ion-exchange reactions dominated the glass corrosion process with water in low temperature leading conditions. The ion-exchange and network hydrolysis reactions together controlled the glass dissolution in high temperature leaching conditions. There was a peak in leach rate at about 70 C and a valley at about 100 C. The surface layer thickness was about 25 [micro]m. Na was almost totally depleted in the surface layer. At low temperature, the glass corrosion increases with leaching time. The glass corrosion remains about constant with leaching time at 90 C. The surface layer formed at 90 C is protective, which is less porous than the surface layer formed at 40 and 70 C.

Sheng, J. (Kyoto Univ., Osaka (Japan)); Luo, S.; Tang, B. (China Inst. of Atomic Energy, Beijing (China))

1999-01-01

59

The leaching behavior of borate waste glass SL-1  

SciTech Connect

Vitrification is an attractive approach for treatment of the borate waste from nuclear power plants. SL-1 glass is a suitable borosilicate glass form to solidify the borate waste containing relatively high quantities of B and Na. The leaching behavior of SL-1 glass in deionized water has been investigated. Compared to the HLW-glass, the network structure of SL-1 glass is weak. It was found that the ion-exchange reactions dominated the glass corrosion process with water in low temperature leading conditions. The ion-exchange and network hydrolysis reactions together controlled the glass dissolution in high temperature leaching conditions. There was a peak in leach rate at about 70 C and a valley at about 100 C. The surface layer thickness was about 25 {micro}m. Na was almost totally depleted in the surface layer. At low temperature, the glass corrosion increases with leaching time. The glass corrosion remains about constant with leaching time at 90 C. The surface layer formed at 90 C is protective, which is less porous than the surface layer formed at 40 and 70 C.

Sheng, J. [Kyoto Univ., Osaka (Japan)] [Kyoto Univ., Osaka (Japan); Luo, S.; Tang, B. [China Inst. of Atomic Energy, Beijing (China)] [China Inst. of Atomic Energy, Beijing (China)

1999-11-01

60

Temperature dependence of elastic properties in alkali borate binary glasses  

NASA Astrophysics Data System (ADS)

The elastic properties of alkali borate glasses, xM 2O·(100 - x)B 2O 3 (M = Li, Na, K, Rb, Cs, x = 14, 28), have been investigated by Brillouin scattering spectroscopy from room temperature up to 1100 °C. Above the glass transition temperature, Tg, the longitudinal sound velocity, VL, decreases markedly on heating. Such significant changes of the elastic properties result from the breakdown of the glass network above Tg. Alkali borate family with the same x shows the similar behavior in the temperature variations of VL up to around Tg. The absorption coefficient, ?L, increases gradually above Tg. With the increase of the size of an alkali ion, the slope of VL just above Tg decreases. Since the fragility is related to the slope, the present results suggest that the fragility of alkali borate glasses increases as the size of alkali ion decreases. Such an alkali dependence of the fragility is discussed on the basis of the fluctuation of the boron coordination number.

Kawashima, Mitsuru; Matsuda, Yu; Kojima, Seiji

2011-05-01

61

XRD and FTIR studies the effect of heat treatment and doping the transition metal oxide on LiNbO3 and LiNb3O8 nano-crystallite phases in lithium borate glass system  

NASA Astrophysics Data System (ADS)

Glasses of various compositions in the system 90 Li2B4O7sbnd 10 Nb2O5 mixed with T.M ions (where T.M is the transition metal) were prepared by quenching technique. Heat-treatment of the parent glasses was performed at 540, 570 and 620 °C, for 5 and 16 h. The glass structure evolution during the controlled crystallization was examined by XRD and FT-IR spectroscopy analysis. The crystalline phases present in the glass ceramics were identified via X-ray diffraction as a function of heat treatment. The FT-IR data propose for these glasses and heat-treated glass network structures mainly built by: di-, tri-, tetra-, penta-and ortho-borate groups. It was found that the quantitative evolution of these various borate species in the glass structures is influenced by the transition metal. A detailed discussion relating to the N4 evolution with the T.M content was made.

Kashif, Ismail; Soliman, Ashia A.; Sakr, Elham M.; Ratep, Asmaa

2013-09-01

62

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

63

Third order nonlinear optical properties of bismuth zinc borate glasses  

SciTech Connect

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

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

2013-12-28

64

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

NASA Astrophysics Data System (ADS)

Combined optical and infrared absorption spectra of V2O5-doped cadmium borate glasses were investigated before and after gamma irradiation with a dose of 8 Mrad (=8 × 104 Gy). The undoped base cadmium borate glass reveals a spectrum consisting of strong charge transfer UV absorption bands which are related to the presence of unavoidable contaminated trace iron impurities (mainly Fe3+). The V2O5-doped glasses reveal an extra band at 380 nm and the high V2O5-content glass also shows a further band at about 420 nm. The observed optical spectrum indicates the presence of vanadium ions mainly in the pentavalent state (d0 configuration). The surplus band at 420 nm shows that some trivalent vanadium ions are identified at high V2O5 content. The optical spectra of the glasses after gamma irradiation show small decrease of the intensity of the UV absorption which are interpreted by assuming the transformation of some Fe3+ ions by photochemical reactions with the presence of high content (45 mol%) of heavy massive CdO causing some shielding behavior. FT infrared absorption spectra of the glasses show vibrational bands due to collective presence of triangular and tetrahedral borate groups in their specific wavenumbers. The FTIR spectra are observed to be slightly affected by both the V2O5-dopants being present in modifying low percent or gamma irradiation due to the presence of high content heavy CdO.

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

2014-10-01

65

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

NASA Technical Reports Server (NTRS)

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

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

1998-01-01

66

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

67

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

SciTech Connect

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

Jiao, Qing; Yu, Xue; Xu, Xuhui; Zhou, Dacheng; Qiu, Jianbei, E-mail: qiu@kmust.edu.cn

2013-06-15

68

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

NASA Astrophysics Data System (ADS)

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

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

2012-12-01

69

Synthesis and studies on microhardness of alkali zinc borate glasses  

SciTech Connect

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

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

2014-04-24

70

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

71

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

72

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

NASA Astrophysics Data System (ADS)

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

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

2014-11-01

73

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

PubMed

We have synthesized TiO2 doped strontium borate glasses, 70B2 O3 -(30-x)SrO-xTiO2 and 70B2 O3 -20SrO(10-x)Na2 O-xTiO2 . The composition dependence of glass structure, density, thermal properties, durability, and cytotoxicity of degradation products was studied. Digesting the glass in mineral acid and detecting the concentrations of various ions using an ICP provided the actual compositions that were 5-8% deviated from the theoretical values. The structure was investigated by means of (11) B magic angle spinning (MAS) NMR spectroscopy. DSC analyses provided the thermal properties and the degradation rates were measured by measuring the weight loss of glass disc-samples in phosphate buffered saline at 37°C in vitro. Finally, the MTT assay was used to analyze the cytotoxicity of the degradation products. The structural analysis revealed that replacing TiO2 for SrO or Na2 O increased the BO3 /BO4 ratio suggesting the network-forming role of TiO2 . Thermal properties, density, and degradation rates also followed the structural changes. Varying SrO content predominantly controlled the degradation rates, which in turn controlled the ion release kinetics. A reasonable control (2-25% mass loss in 21 days) over mass loss was achieved in current study. Even though, very high concentrations (up to 5500 ppm B, and 1200 ppm Sr) of ions were released from the ternary glass compositions that saturated the degradation media in 7 days, the degradation products from ternary glass system was found noncytotoxic. However, quaternary glasses demonstrated negative affect on cell viability due to very high (7000 ppm) Na ion concentration. All the glasses investigated in current study are deemed fast degrading with further control over degradation rates, release kinetics desirable. © 2014 Wiley Periodicals, Inc. J Biomed Mater Res Part A, 2014. PMID:25366812

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

2014-11-01

74

The effect of europium oxide impurity on the optical and physical properties of lithium potassium borate glass  

NASA Astrophysics Data System (ADS)

The most hosts that is utilized in scientific application is borate glass. By using melt-quenching technique, five samples of lithium potassium borate (LKB) doped with different concentration of europium oxide (Eu2O3) were prepared. To investigate the influence of dopant on the optical and physical characteristics of the proposed glass, two methods have been applied (XRD, PL). The amorphous nature was confirmed by X-ray diffraction (XRD). The physical parameters of the glass matrix doped by different oxidation state have been analyzed, these parameters are density, molar volume, ion concentration, inter-nuclear distance, and polaron radius. The exchange in the concentration of Eu3+ indicated the influence of Eu as a dopant on the photoluminescence (PL) emission of LKB glasses. The emission spectrum of LKB:Eu3+ show a chain of emission bands, which are attributed to 5 D 0-7 F r ( r = 1-4) transition of Eu3+. The luminescence studies showed four peaks 590 (yellow), 613 (orange), 650 (red), and 698 nm (red) for all samples except sample 0, the high luminescence efficiency is in emitting orange light at 613 nm.

Maqableh, M. M. A.; Hashim, S.; Alajerami, Y. S. M.; Mhareb, M. H. A.; Dawwud, R. S.; Saidu, A.

2014-07-01

75

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

PubMed

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

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

2015-03-01

76

Novel method for early investigation of bioactivity in different borate bio-glasses  

NASA Astrophysics Data System (ADS)

Some ternary borate glasses were prepared and corrosion behavior of such ternary borate glasses after immersion in aqueous dilute phosphate solution was studied using different immersion times. Fourier transform infrared (FTIR) absorption spectral measurements were done before and after immersion in the mentioned solution for extended times up to 2 days to justify the appearance of the characteristic FTIR bands due to calcium phosphate (hydroxyapatite (HA)) which is considered as the potential indication of bioactivity. Experimental IR data confirm the beginning of the appearance of FTIR bands at about 580 and 620 cm-1 after 3 days and the complete resolution with its characteristic split form after 1 week and more. Deconvolution analysis technique (DAT) of the FTIR spectrum was employed to investigate the bioactivity of such ternary borate system after a short period of immersion. The corrosion behavior of such glasses is explained in relation to a suggested hydrolysis followed by direct dissolution mechanism. The ease of dissolution of all the borate glasses constituents explains the formation of calcium phosphate and conversion to crystalline hydroxyapatite within the borate glass matrix. X-ray diffraction may be used to retrace the structural changes and degree of crystallinity of the prepared glasses.

Abdelghany, A. M.

77

Novel method for early investigation of bioactivity in different borate bio-glasses.  

PubMed

Some ternary borate glasses were prepared and corrosion behavior of such ternary borate glasses after immersion in aqueous dilute phosphate solution was studied using different immersion times. Fourier transform infrared (FTIR) absorption spectral measurements were done before and after immersion in the mentioned solution for extended times up to 2 days to justify the appearance of the characteristic FTIR bands due to calcium phosphate (hydroxyapatite (HA)) which is considered as the potential indication of bioactivity. Experimental IR data confirm the beginning of the appearance of FTIR bands at about 580 and 620 cm(-1) after 3 days and the complete resolution with its characteristic split form after 1 week and more. Deconvolution analysis technique (DAT) of the FTIR spectrum was employed to investigate the bioactivity of such ternary borate system after a short period of immersion. The corrosion behavior of such glasses is explained in relation to a suggested hydrolysis followed by direct dissolution mechanism. The ease of dissolution of all the borate glasses constituents explains the formation of calcium phosphate and conversion to crystalline hydroxyapatite within the borate glass matrix. X-ray diffraction may be used to retrace the structural changes and degree of crystallinity of the prepared glasses. PMID:22455957

Abdelghany, A M

2013-01-01

78

Factors affecting optical dispersion in borate glass systems  

NASA Astrophysics Data System (ADS)

Series of ternary glass systems namely, Na2O, B2O3, and RO (R=Ba or Mg) doped with TiO2 are synthesized. The present glasses are dictated by requirement for a small refractive index and a small nonlinear coefficient needed for waveguide and laser fabrication requirements. The effect of MgO and BaO as alkaline earth metals on the optical properties of the glass systems is investigated. The dependence of the refractive index and extinction coefficient dispersion curves on composition is carried out over a wavelength range of 0.3 2.5?m. Applying a genetic algorithm technique, the parameters of Sellmeier dispersion formula that fit index data to accuracy consistent well with the measurements are given. The zero material dispersion-wavelength (ZMDW) and group velocity are also determined using the refractive index data. The Fermi level is calculated exploiting the extinction coefficient dispersion curves. The absorption coefficient, both direct and indirect optical energy gaps, and Urbach energy are evaluated using the absorption edge calculations. The different factors that play a role for controlling the refractive indices such as coordination number, electronic polarizability, field strength of cations, bridging and nonbridging oxygen, and optical basicity are discussed in accordance with the obtained index data. IR spectroscopy is used as a structural probe of the nearest-neighbor environment in the glass network.

Abdel-Baki, Manal; Abdel-Wahab, F. A.; Radi, Amr; El-Diasty, Fouad

2007-08-01

79

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

SciTech Connect

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

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

2007-05-09

80

In vitro evaluation of cytotoxicity of silver-containing borate bioactive glass.  

PubMed

The cytotoxicity of silver-containing borate bioactive glass was evaluated in vitro from the response of osteoblastic and fibroblastic cells in media containing the dissolution products of the glass. Glass frits containing 0-2 weight percent (wt %) Ag were prepared by a conventional melting and quenching process. The amount of Ag dissolved from the glass into a simulated body fluid (SBF), measured using atomic emission spectroscopy, increased rapidly within the first 48 h, but slowed considerably at longer times. Structural and microchemical analysis showed that the formation of a hydroxyapatite-like layer on the glass surface within 14 days of immersion in the SBF. The response of MC3T3-E1 and L929 cells to the dissolution products of the glass was evaluated using SEM observation of cell morphology, and assays of MTT hydrolysis, lactate dehydrogenase release, and alkaline phosphatase activity after incubation for up to 48 h. Cytotoxic effects were found for the borate glass containing 2 wt % Ag, but not for 0.75 and 1 wt % Ag. This borate glass containing up to ?1 wt % Ag could provide a coating material for bacterial inhibition and enhanced bioactivity of orthopaedic implant materials such as titanium. PMID:20878930

Luo, Shi-Hua; Xiao, Wei; Wei, Xiao-Juan; Jia, Wei-Tao; Zhang, Chang-Qing; Huang, Wen-Hai; Jin, Dong-Xu; Rahaman, Mohamed N; Day, Delbert E

2010-11-01

81

Effects of borate-based bioactive glass on neuron viability and neurite extension.  

PubMed

Bioactive glasses have recently been shown to promote regeneration of soft tissues by positively influencing tissue remodeling during wound healing. We were interested to determine whether bioactive glasses have the potential for use in the treatment of peripheral nerve injury. In these experiments, degradable bioactive borate glass was fabricated into rods and microfibers. To study the compatibility with neurons, embryonic chick dorsal root ganglia (DRG) were cultured with different forms of bioactive borate glass. Cell viability was measured with no media exchange (static condition) or routine media exchange (transient condition). Neurite extension was measured within fibrin scaffolds with embedded glass microfibers or aligned rod sheets. Mixed cultures of neurons, glia, and fibroblasts growing in static conditions with glass rods and microfibers resulted in decreased cell viability. However, the percentage of neurons compared with all cell types increased by the end of the culture protocol compared with culture without glass. Furthermore, bioactive glass and fibrin composite scaffolds promoted neurite extension similar to that of control fibrin scaffolds, suggesting that glass does not have a significant detrimental effect on neuronal health. Aligned glass scaffolds guided neurite extension in an oriented manner. Together these findings suggest that bioactive glass can provide alignment to support directed axon growth. PMID:24027222

Marquardt, Laura M; Day, Delbert; Sakiyama-Elbert, Shelly E; Harkins, Amy B

2014-08-01

82

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

NASA Astrophysics Data System (ADS)

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

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

2013-04-01

83

Evolution of the spectral characteristics upon annealing of lithium borate glasses containing europium and aluminum  

NASA Astrophysics Data System (ADS)

The spectral and structural characteristics of lithium borate glasses containing europium and aluminum have been investigated upon annealing at different temperatures. It has been found that the spectral characteristics of the studied system change nonmonotonically with an increase in the annealing temperature. After annealing at a temperature of 600°C, the luminescence spectra of the glasses exhibit broad structureless bands that are specific for the amorphous phase containing Eu3+ ions. Then, after annealing at T = 700°C, narrow lines appear in the wavelength ranges 585-595 and 610-620 nm, which correspond to the luminescence of the Eu(BO2)3 and EuAl3(BO3)4 borates. A further increase in the annealing temperature ( T = 800-900°C) leads to the disappearance of europium aluminum borate. In the luminescence spectra of these samples, there are narrow bands in the wavelength range ? = 585-595 nm, which are typical of europium metaborate. Finally, at a temperature of 1050°C, these bands disappear and narrow lines appear again in the wavelength range 610-620 nm, which are characteristic of the EuAl3(BO3)4 borate. Thus, the temperature annealing makes it possible to purposely change the spectral characteristics of the studied system in the wavelength range 590-615 nm.

Shmurak, S. Z.; Kedrov, V. V.; Kiselev, A. P.; Zver'kova, I. I.

2013-02-01

84

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

NASA Astrophysics Data System (ADS)

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

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

2003-10-01

85

Gamma-ray attenuation coefficients in bismuth borate glasses  

Microsoft Academic Search

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

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

2002-01-01

86

Complex Heat Capacity of Lithium Borate Glasses Studied by Modulated DSC  

NASA Astrophysics Data System (ADS)

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

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

2006-05-01

87

Physical, optical, structural and gamma-ray shielding properties of lead sodium borate glasses  

Microsoft Academic Search

Lead sodium borate glasses with compositions xPbO:20Na2O:(80?x)B2O3 (where x=5, 10, 15, 20, 25, 30, 35, 40, 45, 50 and 55mol%) have been prepared using melt-quenching method and investigated on their optical, physical, structural and gamma-rays shielding properties. The densities of these glass samples were increased with increase in PbO concentration. The FTIR spectra and molar volumes indicate that PbO acts

P. Limkitjaroenporn; J. Kaewkhao; P. Limsuwan; W. Chewpraditkul

2011-01-01

88

Study of Electrical Conductivity and Dielectric Behaviour of Molybdenum containing Bismuth Borate Glasses  

NASA Astrophysics Data System (ADS)

Bismuth borate glasses containing MoO3 content have been synthesized by the standard melt-quenching technique. The samples have been characterized by X-ray diffraction and scanning electron microscopy. Frequency and temperature dependent conductivity measurements have been carried out in the range of 20Hz to 1MHz and in the temperature range of 373K to 623K respectively. The frequency dependent conductivity has been studied using both conductivity and modulus formalisms. The dielectric permittivity (?' and ?"), electrical modulus (M*) and dielectric loss were also studied of the prepared glasses. The values of ?' and ?'' are found to decrease with increase in frequency.

Kishore, N.; Sanjay; Agarwal, A.; Dahiya, Sanjay; Pal, Inder

2015-02-01

89

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

NASA Astrophysics Data System (ADS)

In a Ce3+-Yb3+ system, two mechanisms are proposed so far namely, the quantum cutting mechanism and the electron transfer mechanism explaining Yb3+ infrared luminescence under Ce3+ excitation. Among them, the quantum cutting mechanism, where one Ce3+ photon (ultraviolet/blue) gives rise to two Yb3+ photons (near infrared) is widely sought for because of its huge potential in enhancing the solar cell efficiency. In present study on Ce3+-Yb3+ codoped borate glasses, Ce3+ sensitized Yb3+ luminescence at ˜1 ?m have been observed on Ce3+ 5d state excitation. However, the intensity of sensitized Yb3+ luminescence is found to be very weak compared to the strong quenching occurred in Ce3+ luminescence in Yb3+ codoped glasses. Moreover, the absolute luminescence quantum yield also showed a decreasing trend with Yb3+ codoping in the glasses. The overall behavior of the luminescence properties and the quantum yield is strongly contradicting with the quantum cutting phenomenon. The results are attributed to the energetically favorable electron transfer interactions followed by Ce3+-Yb3+ ? Ce4+-Yb2+ inter-valence charge transfer and successfully explained using the absolute electron binding energies of dopant ions in the studied borate glass. Finally, an attempt has been presented to generalize the electron transfer mechanism among opposite oxidation/reduction property dopant ions using the vacuum referred electron binding energy (VRBE) scheme for lanthanide series.

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

2015-01-01

90

Molecular Dynamics Simulation of Lead Borate and Related Glasses in Multicomponent Systems for Low Melting Vitrification of Nuclear Wastes  

Microsoft Academic Search

Glasses based on lead oxide have excellent properties in general such as low melting point, high chemical durability and high stability of glassy form, which are suitable for the preservation of volatile nuclear wastes in a permanent vitrified form. In order to confirm the long-term performance of lead borate based glasses it is necessary to establish dissolution and diffusion processes

S. Kato; S. Sakida; Y. Benino; T. Nanba

2011-01-01

91

Study of lithium borate glasses containing Bi2O3  

NASA Astrophysics Data System (ADS)

The effect of Bi2O3 addition on the properties of 30Li2O:(70-x)B2O3:xBi2O3 (0?x?35 mol %) has been studied. Density and molar volume are increasing with Bi2O3 content. The observed decrease in glass transition temperature and optical band gap has been explained on the basis of increase in non bridging oxygen which is supported by infrared spectroscopy. From the optical transmittance spectra it is observed that the cut off wavelength increases with Bi2O3 content which is related to the structural changes.

Deshpande, A. V.; Raut, V. D.

2014-04-01

92

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

PubMed

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

Deliormanl?, Aylin M

2015-02-01

93

ESR studies of Mo 5+ ions in potassium-borate and soda-phosphate glasses  

NASA Astrophysics Data System (ADS)

The local symmetry and the interaction between metallic ions in potassium-borate and soda-phosphate glasses with molybdenum were investigated by the ESR method. The coordination polyhedra geometry is distorted from the almost Oh symmetry to C4 v with the increase of molybdenum content in B 2O 3?K 2O glasses. Also, the MoO 2 oxide becomes a former of the network at high content ( x > 40 mol%) together with B 2O 3 oxide, molybdenum ions occupyi the network-former sites. Mo[ 5+ ions are essentially coordinated in P 2O 5?Na 2O glasses by five oxygen ligands in a C4 v symmetry with a Mo?O double bond. The values of bonding coefficients (?2,?1, ?) were estimated using an appropriate LCAO-MO scheme.

Cozar, O.; Ardelean, I.; Simon, S.; David, L.

1993-02-01

94

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

95

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

96

Optical harmonic transformations in borate glasses with Li2B4O7, LiKB4O7, CaB4O7, and LiCaBO3 compositions  

NASA Astrophysics Data System (ADS)

A series of un-doped borate glasses with Li2B4O7, LiKB4O7, CaB4O7, and LiCaBO3 compositions of high optical quality and chemical purity were obtained from corresponding polycrystalline compounds using standard glass synthesis and technological conditions developed by authors. The optically thermopoled second harmonic generation (SHG) effect in the Li2B4O7, LiKB4O7, CaB4O7, and LiCaBO3 glasses were investigated and analyzed.

Padlyak, B. V.; Adamiv, V. T.; Burak, Ya. V.; Kolcun, M.

2013-03-01

97

Molecular Dynamics Simulation of Lead Borate and Related Glasses in Multicomponent Systems for Low Melting Vitrification of Nuclear Wastes  

NASA Astrophysics Data System (ADS)

Glasses based on lead oxide have excellent properties in general such as low melting point, high chemical durability and high stability of glassy form, which are suitable for the preservation of volatile nuclear wastes in a permanent vitrified form. In order to confirm the long-term performance of lead borate based glasses it is necessary to establish dissolution and diffusion processes based on a reliable model of the glass structure. In the present study molecular dynamics (MD) simulation of lead borate based glasses was carried out introducing a dummy negative point charge to reproduce asymmetric PbOn units. Parameters for the dummy charge were optimized based on the comparison between calculated radial distribution function and experimental one. Asymmetric coordination around Pb, for example trigonal bipyramid, was successfully reproduced in the MD simulated binary and ternary glass models. The simple model using the dummy charge was confirmed to be valid for further simulations of multicomponent glasses containing nuclear wastes and heavy elements.

Kato, S.; Sakida, S.; Benino, Y.; Nanba, T.

2011-03-01

98

Coordination and ion-ion interactions of chromium centers in alkaline earth zinc borate glasses probed by electron paramagnetic resonance and optical spectroscopy  

NASA Astrophysics Data System (ADS)

Electron paramagnetic resonance (EPR), optical absorption and FT-IR studies have been carried out on chromium ions incorporated in alkaline earth zinc borate glasses. The EPR spectra exhibit two resonance signals with effective g values at g ? 1.99 and ?1.97. The resonance signal at g ? 1.99 is attributed to the contribution from both the exchange coupled Cr3+-Cr3+ ion pairs and the isolated Cr3+ ions and the resonance signal at g ? 1.97 is due to Cr5+ ions. The paramagnetic susceptibility (?) was calculated from the EPR data at various (123-303 K) temperatures and the Curie temperature (?p) was calculated from the 1/?-T graph. The optical absorption spectra exhibit three bands at ˜360 nm, ˜440 nm and a broad band at ˜615 nm characteristic of Cr3+ ions in an octahedral symmetry. From the observed band positions, the crystal-field splitting parameter Dq and the Racah parameters (B and C) have been evaluated. From the ultraviolet edges, the optical band gap energies (Eopt) and Urbach energy (?E) are calculated. The theoretical optical basicity (?th) of these glasses has also been evaluated. Chromium ions doped alkaline earth zinc borate glasses show BO3 and BO4 structural units in the FT-IR studies.

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

2013-05-01

99

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

PubMed

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

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

2015-02-01

100

Experimental and theoretical studies of the structure of tellurate-borate glasses network.  

PubMed

The structural properties of the xTeO(2) x (1-x)B(2)O(3) glasses (x = 0.6; 0.7) were investigated by FT-IR spectroscopy. From the analysis of the FTIR spectra, it is reasonable to assume that by the increasing of boron ions content, the tetrahedral [BO(4)] units are gradually replaced by the trigonal [BO(3)] units. The increase in the number of non-bridging oxygen atoms would decrease the connectivity of the glass network and will yield the depolymerization of the borate chains. The molecular structure and vibrational frequencies of the proposed structural models have been studied by exploring the density functional theory (DFT) calculations. The FTIR spectra of the xTeO(2) x (1-x)B(2)O(3) vitreous systems were compared with the calculated spectrum. This procedure allowed us to assign most of the observed IR bands. PMID:20127395

Rada, Simona; Culea, Eugen; Neumann, Manfred

2010-08-01

101

Complex Heat Capacity of Lithium Borate Glasses Studied by Modulated DSC  

SciTech Connect

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

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

2006-05-05

102

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

PubMed Central

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

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

2014-01-01

103

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

NASA Astrophysics Data System (ADS)

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

Olumoroti, Akinloluwa T.

104

Effect of modifier ions on the covalency of Nd 3+ ions in cadmium borate glasses  

NASA Astrophysics Data System (ADS)

An investigation of the optical absorption spectra of 1 mol% Nd 3+ ions in cadmium borate glass and effect of network modifiers, alkali ions, Li, Na and K is presented. Special emphasis is laid on the position, intensity parameters, ? ?,? =2,4,6, of the 4I 9/2 ? 4F 7/2, 4S 3/2, and hypersensitive 4I 9/2 ? 4G 5/2 transitions. The effect of covalency of the rare earth ion sites on the transition probabilities was estimated from the variation of the profiles of the absorption spectra in terms of the nephelauxetic effect. The variation of intensity ratio and the Judd-Ofelt parameter, ? 2, with composition depended on the Nd-O covalency.

Ravi Kanth Kumar, V. V.; Bhatnagar, Anil K.

1998-11-01

105

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

NASA Technical Reports Server (NTRS)

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

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

1985-01-01

106

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

NASA Astrophysics Data System (ADS)

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

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

2014-11-01

107

Sensitized red luminescence from Bi 3+ co-doped Eu 3+: ZnO-B 2O 3 glasses  

NASA Astrophysics Data System (ADS)

Photoluminescence properties of Bi 3+ co-doped Eu 3+ containing zinc borate glasses have been investigated and the results are reported here. Bright red emission due to a dominant electric dipole transition 5D 0? 7F 2 of the Eu 3+ ions has been observed from these glasses. The nature of Stark components from the measured fluorescence transitions of Eu 3+ ions reveal that the rare earth ions could take the lattice sites of C s or lower point symmetry in the zinc borate glass hosts. The significant enhancement of Eu 3+ emission intensity by 346 nm excitation ( 1S 0? 3P 1 of Bi 3+ ions) elucidates the sensitization effect of co-dopant. The energy transfer mechanism between sensitizer (Bi 3+) and activator (Eu 3+) ions has been explained.

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

2009-11-01

108

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

NASA Astrophysics Data System (ADS)

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

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

2012-12-01

109

Spectroscopic, mechanical and magnetic characterization of some bismuth borate glasses containing gadolinium ions  

NASA Astrophysics Data System (ADS)

The ultrasonic parameters, the optical parameters along with the IR spectroscopy and magnetic susceptibility studies have been employed to explore the role of Gd 2O 3 in the structure of the glasses xGd 2O 3-60B 2O 3-10MoO 3-(30- x)Bi 2O 3, with 0 ? x ? 7 mol %. IR analysis indicates that Gd 2O 3 is preferentially incorporated into the borate network-forming BO 4 units. It is assumed that Bi 2O 3 and MoO 3 enter the structure as modifiers in the form of BiO 6 and MoO 6 only. The compositional dependence of the mechanical and the optical parameters are interpreted in terms of the transformation of the structural units BO 3 into BO 4, the increase in the number of bridging oxygen atoms, and the substitution of high bond strength Gd-O, in the place of low bond strength Bi-O bond. The results of the magnetic susceptibility reveal the paramagnetic behavior as described by the Curie-Weiss law and indicating the presence of weak antiferromagnetic exchange interactions between Gd 3+ ions. The magnetic entropy change of the glasses was determined according to the temperature and magnetic field dependence of magnetization.

Saddeek, Yasser B.; Yahia, I. S.; Aly, K. A.; Dobrowolski, W.

2010-08-01

110

Structural and morphological transformations of BaTiO3 nanocrystals in thin layers of borate oxide glasses  

NASA Astrophysics Data System (ADS)

The influence of thin layers (2-15 ?m) of some oxide glass melts on BaTiO3 nanocrystallites has been investigated using X-ray diffractometry and scanning electron microscopy. It has been shown that lead borate and sodium borate glass melts bring about the dissolution of BaTiO3 nanocrystallites and the subsequent crystallization in glasses of lead titanate PbTiO3 and sodium titanate Na2TiO3, respectively. It has been found that thin layers of melts of these glasses have a strong orientation effect on crystallites of the PbTiO3 and Na2TiO3 compounds newly synthesized from barium titanate. The orientation effect exerted by these glass layers results in the formation of a pronounced texture of the perovskite crystallites with the texture axes oriented along the [100] and [001] directions parallel to the surface normal of the substrate for lead titanate and the orientation of the planes of the film surface for the sodium titanium oxide.

Kedrov, V. V.; Shmyt'ko, I. M.

2015-02-01

111

Spectroscopy of erbium in La3+-doped tellurite glass & fibres  

Microsoft Academic Search

We study the spectroscopic properties of erbium doped tellurite glass and the effect of co-doping with lanthanum. This is a route towards the development of versatile fibre lasers for the mid-infrared.

M. R. Oermann; H. Ebendorff-Heidepriem; Yahua Li; T. M. Monro

2008-01-01

112

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

113

Defect formation of gamma irradiated MoO3-doped borophosphate glasses.  

PubMed

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

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

2013-10-01

114

Study on visible luminescence of the Tm 3 + : 1D 2 ? 3 F 4 emission state in lead borate titanate aluminumfluoride glasses  

NASA Astrophysics Data System (ADS)

This paper reports the visible luminescence properties of 1D 2 state of Tm 3 + -doped lead borate titanate aluminumfluoride (LBTAFTm) glasses. The absorption and luminescence was analyzed within the frame work of Judd-Ofelt model. The reliability of J-O intensity parameters obtained from the experimental oscillator strengths have satisfactorily been correlated with the calculated oscillator strengths with small r.m.s deviation of ± 0.12 × 10 -6 by the least square fit analysis. Upon 359 nm excitation, the luminescence spectra show only one emission band at 458 nm (blue) corresponding to the 1D 2 ? 3 F 4 transition in the spectral region 400-500 nm. No luminescence quenching has been observed with the increase of Tm 3 + concentration. The decay profiles of the 1D 2 level have shown single-exponential nature for all the concentrations and the decay times were found to decrease with the increase of concentration. The stimulated emission cross-section ( ?e) for the observed emission transition has also been computed. The large quantum efficiency (?) of the 1D 2 level suggests the utility of LBTAFTm glass as a potential host for optical device applications at 458 nm emission wavelength.

Suhasini, T.; Jamalaiah, B. C.; Sasikala, T.; Reddy, G. V. Lokeswara; Moorthy, L. Rama

2012-03-01

115

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

SciTech Connect

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

Lee, Sung Keun; Eng, Peter J.; Mao, Ho-kwang; Meng, Yue; Shu, Jinfu (SNU); (CIW); (UC)

2008-06-16

116

Spectroscopic properties of Ho3+ ions doped in tellurite glass.  

PubMed

Spectroscopic properties of Ho3+ doped tellurite glass (1 mol.% of Ho3+) have been studied. The absorption and fluorescence spectra have been recorded and analysed using the Judd-Offelt theory. The analysis indicates that Ho doped tellurite glasses can show lasing on the 5F4 (5S2)-5I8 transition (548.0 nm). PMID:14607219

Rai, S B; Singh, Anant Kumar; Singh, Shiv Kumar

2003-12-01

117

Fabrication and characterization of neodymium-doped glass waveguides  

Microsoft Academic Search

Waveguides prepared in neodymium-doped lithium-silicate glass by silver-ion exchange are discussed. Refractive index change and diffusion coefficient due to ion exchange are determined. It is observed that silver-ion exchange does not influence the emission wavelength of neodymium-doped glass

S. I. Najafi; W.-J. Wang; J. F. Currie; R. Leonelli; J. L. Brebner

1989-01-01

118

Effect of Co(2+) and Ni(2+)-doped zinc borate nano crystalline powders by co-precipitation method.  

PubMed

A simple co-precipitation method has been used for the synthesis of Co(2+) and Ni(2+)-doped zinc borate nanopowders. X-ray diffraction (XRD), Fourier transform infrared (FT-IR), UV/Vis absorption, Scanning electron microscope (SEM) with EDS and photoluminescence (PL) spectroscopies techniques has been employed for their characterization. Powder X-ray diffraction data reveals that the crystal structure belongs to monoclinic for both as-prepared samples. SEM images showed surface morphology of the prepared samples. Optical absorption spectra showed the characteristic bands of doped ions in octahedral site symmetry. From the optical absorption data crystal field and inter-electronic repulsion parameters are evaluated. The FT-IR spectra showed the characteristic vibrational bands related to ZnO, BO3 and BO4 molecules. Photoluminescence spectra exhibited the emission bands in ultraviolet and blue regions. PMID:25706597

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

2015-05-01

119

IR luminescence in bismuth-doped germanate glasses and fibres  

SciTech Connect

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

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

2013-02-28

120

Characterization of new erbium-doped tellurite glasses and fibers  

E-print Network

of their excellent optical and chemical properties. The emission spectrum from erbium in tellurite glasses is almost. Introduction Erbium-doped tellurite glasses have optical and chemical properties suitable for optical applica, many valence states of tellurium, a low-bonding strength of Te­O, low glass transition and chemi- cal

Dierolf, Volkmar

121

Effect of B2O3 on luminescence of erbium doped tellurite glasses.  

PubMed

The B2O3 was introduced into the Er3+ doped TeO2-ZnO-Na2O glass to increase the phonon energy of the host. The effect of B2O3 on the non-radiative rate of the 4I11/2-->4I13/2 transition of Er3+, the lifetime of the 4I11/2 and 4I13/2 levels, the green and red upconversion emissions intensity, and the 4I13/2-->4I15/2 emission intensity was discussed. The results show that the phonon energy of boro-tellurite glass is close to that of germanate glass and is quite smaller than that of borate glass. The lifetime of 4I11/2 level and the upconversion emissions decrease with increasing B2O3 concentration. The higher OH group concentration presented in the boro-tellurite glass may shorten the lifetime of 4I13/2 level and also reduce the quantum efficiency of 4I13/2-->4I15/2 emission. The future dehydrating procedures are suggested to enhance the efficiency of amplification at 1.5 microm band. PMID:16843711

Shen, Xiang; Nie, Qiuhua; Xu, Tiefeng; Dai, Shixun; Wang, Xunsi

2007-02-01

122

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

PubMed

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

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

2011-09-21

123

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. PMID:20680413

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

2010-01-01

124

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

125

Study on borate glass system containing with Bi 2O 3 and BaO for gamma-rays shielding materials: Comparison with PbO  

Microsoft Academic Search

In this work, the mass attenuation coefficients and shielding parameters of borate glass matrices containing with Bi2O3 and BaO have been investigated at 662keV, and compare with PbO in same glass structure. The theoretical values were calculated by WinXCom software and compare with experiential data. The results found that the mass attenuation coefficients were increased with increasing of Bi2O3, BaO

J. Kaewkhao; A. Pokaipisit; P. Limsuwan

2010-01-01

126

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

NASA Astrophysics Data System (ADS)

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

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

2009-06-01

127

Effect of SiO2 and Al2O3 addition on the density, Tg and CTE of mixed alkali - alkaline earth borate glass  

NASA Astrophysics Data System (ADS)

Mixed alkali — alkaline earth borate glasses, with the addition of silica and alumina, have been studied for their density, Tg and CTE with a view of exploring the applicability of these glasses in glass to metal sealing applications. It has been observed that silica addition results in an increase in density and Tg while the alumina addition decreases the density and Tg. The variation in CTE exhibits minima with the addition of both, silica and alumina. An attempt is made here to explain the observed variations in the properties on the basis of different mass of the additives, number of non bridging oxygens (NBOs) and other changes in the glass network.

Deshpande, A. M.; Deshpande, V. K.

2009-07-01

128

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

NASA Astrophysics Data System (ADS)

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

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

2014-11-01

129

Photoinduced phenomena in chalcogenide glasses doped with metals  

E-print Network

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

Boolchand, Punit

130

Gamma rays interaction with copper doped lithium phosphate glasses  

NASA Astrophysics Data System (ADS)

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

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

2013-12-01

131

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

132

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

PubMed

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

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

2012-12-01

133

Erbium-Doped Fibers Based on Cesium-Silicate Glasses  

NASA Astrophysics Data System (ADS)

Using modified chemical vapor deposition and solution doping techniques, erbium-doped fibers (EDFs) were prepared based on cesium-silicate glasses. The possibility of manufacturing high-concentration (1-13 wt%) EDFs was shown, and a fiber structure was realized by means of direct doping of cesium-silicate glass with erbium ions. The optical, fluorescence, and gain properties of prepared samples were examined. A maximum gain of 25 dB at 1538 nm was achieved in the fiber at an optimum length of 30 cm at a pump power of 50 mW at 979 nm.

Belov, A. V.; Dianov, E. M.; Devy'atykh, G. G.; Khopin, V. F.; Gur'yanov, A. N.; Zverev, Yu. B.

2000-01-01

134

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

NASA Astrophysics Data System (ADS)

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

Tonooka, Kazuhiko; Shimokawa, Katsuyoshi; Nishimura, Okio

2001-04-01

135

Composition and concentration dependence of spectroscopic properties of Nd 3+-doped tellurite and metaborate glasses  

NASA Astrophysics Data System (ADS)

The spectroscopic properties of tellurite glasses of composition (in mol%) TNKNd: (70 - x)TeO 2-15Nb 2O 5-15K 2O- xNd 2O 3 ( x = 0.1, 1.0, 1.5, 2.0 and 2.5) and TNLNd10: 69TeO 2-15Nb 2O 5-15Li 2O-1.0Nd 2O 3 and lithium metaborate glass of composition LBNNd10: 89LiBO 2-10Nb 2O 5-1.0Nd 2O 3 have been investigated using absorption and emission spectra and decay curve analysis. An energy level analysis has been carried out considering the experimental energy positions of the absorption and emission bands, using the free-ion Hamiltonian model. The spectral intensities have been calculated by using the Judd-Ofelt theory and in turn the radiative properties such as radiative transition probabilities, emission cross-sections, branching ratios and radiative lifetimes have been estimated. The decay curves at the lower concentrations are exponential while they show a non-exponential behavior at higher concentrations (?1.0 mol%) due to energy transfer processes. The effective lifetimes for the 4F 3/2 level are found to decrease with increase in Nd 2O 3 concentration for all the glasses under investigation. The non-exponential decay curves have been well-fitted to the Yokota-Tanimoto model with S = 6, indicating that the nature of energy transfer is of dipole-dipole type and energy migration also plays an important role. The results obtained have been compared with Nd 3+-doped phosphate, fluorophosphate, lead borate, tellurite, germanate and silicate glasses and Nd 3+-doped YAG ceramic and Ca 2Nb 2O 7 crystals.

Jyothi, L.; Venkatramu, V.; Babu, P.; Jayasankar, C. K.; Bettinelli, M.; Mariotto, G.; Speghini, A.

2011-04-01

136

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

SciTech Connect

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

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

2014-04-24

137

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

PubMed

Er(3+) doped Barium tellurofluoroborate glasses (BTFBxE) with the chemical composition (30-x)TeO2+30B2O3+20BaO+20BaF+xEr2O3 (where x=0.01, 0.05, 0.1, 0.5, 1.0 and 2.0 in wt%) were prepared following the melt quenching technique. The different vibrational modes of borates and tellurites in the prepared glasses were explored through FTIR and Raman spectra. The optical absorption spectra have been used to determine the ionic/covalent nature of the metal-ligand bond in the prepared glasses with the help of Nephelauxetic ratio (?) and bonding parameter (?) studies. The optical band gap of direct and indirect allowed transitions were determined from Tauc's plot and the variations of band gap energy with structural arrangements were discussed. The Urbach energy values were determined and the relatively lower values of the Urbach's energy reveal the minimal degree of disorderness in the prepared glasses. The oscillator strengths (fexp and fcal) and Judd-Ofelt (JO) intensity parameters (?2, ?4 and ?6) were calculated with the application of JO theory and the trends of the JO intensity parameters are found to be ?2>?6>?4 for all the prepared glasses with a minimum variation in ?2 intensity parameter values. A bright green emission was observed from the (2)H11/2+(4)S3/2? (4)I15/2 transition and the radiative properties such as transition probability (A), stimulated emission cross-section (?P(E)), branching ratio (?r) and radiative lifetime (?) were calculated using the JO parameters. The suitability of the prepared glasses for the fabrication of photonic devices were also discussed and reported in the present work. PMID:25173526

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

2015-01-25

138

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

NASA Astrophysics Data System (ADS)

Er3+ doped Barium tellurofluoroborate glasses (BTFBxE) with the chemical composition (30 - x)TeO2 + 30B2O3 + 20BaO + 20BaF + xEr2O3 (where x = 0.01, 0.05, 0.1, 0.5, 1.0 and 2.0 in wt%) were prepared following the melt quenching technique. The different vibrational modes of borates and tellurites in the prepared glasses were explored through FTIR and Raman spectra. The optical absorption spectra have been used to determine the ionic/covalent nature of the metal-ligand bond in the prepared glasses with the help of Nephelauxetic ratio (?) and bonding parameter (?) studies. The optical band gap of direct and indirect allowed transitions were determined from Tauc's plot and the variations of band gap energy with structural arrangements were discussed. The Urbach energy values were determined and the relatively lower values of the Urbach's energy reveal the minimal degree of disorderness in the prepared glasses. The oscillator strengths (fexp and fcal) and Judd-Ofelt (JO) intensity parameters (?2, ?4 and ?6) were calculated with the application of JO theory and the trends of the JO intensity parameters are found to be ?2 > ?6 > ?4 for all the prepared glasses with a minimum variation in ?2 intensity parameter values. A bright green emission was observed from the 2H11/2 + 4S3/2 ? 4I15/2 transition and the radiative properties such as transition probability (A), stimulated emission cross-section (?PE), branching ratio (?r) and radiative lifetime (?) were calculated using the JO parameters. The suitability of the prepared glasses for the fabrication of photonic devices were also discussed and reported in the present work.

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

2015-01-01

139

Investigation of structural properties of lead strontium borate glasses for gamma-ray shielding applications  

Microsoft Academic Search

Glasses of the system PbO–SrO–B2O3 with the value of molar ratio R (=PbO\\/B2O3) in the region 0.14?R?2.0 were prepared using the melt quenching technique. In order to evaluate gamma-ray shielding properties for glass samples, mass attenuation coefficients have been calculated with the XCOM computer program. The longitudinal velocities of ultrasonic waves were measured in these glass samples at room temperature

R. S. Kaundal; Sandeep Kaur; Narveer Singh; K. J. Singh

2010-01-01

140

Structural and optical properties of barium titanate modified bismuth borate glasses  

NASA Astrophysics Data System (ADS)

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

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

2014-11-01

141

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

142

Impedance spectroscopic characterization of Sm2O3 containing lithium borate glasses  

NASA Astrophysics Data System (ADS)

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

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

2014-12-01

143

Bi-doped glasses for broadband fiber light source  

NASA Astrophysics Data System (ADS)

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

Fujimoto, Yasushi

2009-02-01

144

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

SciTech Connect

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

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

2014-04-24

145

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

NASA Astrophysics Data System (ADS)

The DC Conductivity and Differential Thermal Analysis of glasses with composition (30-x)Li2O?xV2O5?20Bi2O3?50B2O3(x=15, 10, 5) has been carried out in order to study the effect of replacing the Transition Metal Oxide (TMO) with alkali oxide. A significant increase in the DC conductivity has been observed with increase in alkali content. Again the thermal measurements have shown the decrease in both glass transition temperature (Tg) and crystallization temperature (Tx). The Glass Stability (GS) and Glass Forming Ability (GFA) have also been calculated and these also were found to decrease with increase in alkali oxide content at the cost of TMO.

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

2014-04-01

146

Magnetic behaviour of some potassium-borate glasses with vanadium and manganese ions  

NASA Astrophysics Data System (ADS)

The temperature dependence of the magnetic susceptibility of x(MnO· yV 2O 5)·(1- x) [2B 2O 3·K 2O] glasses with 0 < x ? 50 mol% and y = 1, 2, 5, have been investigated. The valence states and distribution mode of the transition metal ions in the glass matrix depend on the concentration of these ions.

Ilonca, Gh.; Ardelean, I.; Cozar, O.

1986-02-01

147

Optical properties of Er3+-doped fluoride glass channel waveguides  

NASA Astrophysics Data System (ADS)

The latest results on the preparation and characterization of Er3+-doped fluoride glass channel waveguides are presented. The waveguides are prepared by means of ion exchange between fluoride and chloride ions, through a silica mask, on ZBLA (ZrF4-BaF2-LaF3-AlF3) fluoride glass substrate. Single mode propagation is demonstrated at 1.55 ?m for a 10-mm long, 5-?m wide waveguide. Propagation losses are found to be not greater than 0.28 dB/cm. An "on/off' gain of 3.9 dB is measured at the output of a 1% Er3+-4% Ce3+-doped fluoride waveguide, with about 240 mW incident pump power at 980 nm. Modelisation studies show that net gain could be achieved in (Er3+, Ce3+) doubly-doped and (Er3+, Ce3+, Yb3+) triply doped fluoride waveguides.

Haquin, Herve; Vasilief, Ion; Fonteneau, Gilles; Nazabal, Virginie; Adam, Jean-Luc; Guy, Stephan; Jacquier, Bernard; Couchaud, Maurice; Rabarot, Maurice; Fulbert, Laurent

2004-06-01

148

Broadband saturable absorber with cobalt-doped tellurite glasses.  

PubMed

A robust solid-state saturable absorber was developed with cobalt-ion-doped tellurite glasses that has a broad saturable-absorption band in the near-infrared. A nonlinear optical absorber was measured by the Z-scan technique. Numerically fitting the Z-scan experimental data yields excited-state absorption cross sections at a 1064-nm laser wavelength of sigma(es) = 1.45 x 10(-20) and sigma(es) = 1.15 x 10(-20) cm2 for 1.0- and 2.5-at. % Co2+-doped glasses, respectively. PMID:13677539

Wu, E; Chen, Hao; Sun, Zhenrong; Zeng, Heping

2003-09-15

149

Neptunium concentrations in solutions contacting actinide-doped glass  

SciTech Connect

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

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

1982-07-01

150

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

SciTech Connect

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

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

2010-01-15

151

Investigations on spectral features of tungsten ions in sodium lead alumino borate glass system  

NASA Astrophysics Data System (ADS)

Na2O-PbO-Al2O3-B2O3 (NPAB) glasses mixed with different concentrations of WO3 (ranging from 0 to 2.5 mol%) are synthesized by conventional melt quenching method. The samples are characterized by X-ray diffraction (XRD), optical absorption, Electron paramagnetic resonance (EPR) and Fourier transform infrared (FT-IR) spectroscopic techniques. Glass formation is confirmed by X-ray diffraction spectra. The optical absorption spectra of these glasses exhibited a predominant broad band peak at about 850-870 nm is identified due to dxy-dx2-y2 transition of W5+ ions. From the optical absorption spectral data, optical band gap (Eopt) and Urbach energy (?E) are evaluated. From EPR spectra the strength of the signal is increased and hyperfine splitting is resolved with increasing concentration of WO3 in the glass matrix. The FT-IR spectral studies have pointed out the existence of conventional BO3, BO4, B-O-B, PbO4, WO4 and WO6 structural units of these glasses. Various physical properties and optical basicity are also evaluated with respect to the concentration of WO3 ions.

Madhuri, V.; Kumar, J. Santhan; Rao, M. Subba; Cole, Sandhya

2015-03-01

152

White light generation from Dy3+ doped tellurite glass  

NASA Astrophysics Data System (ADS)

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

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

2014-02-01

153

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

154

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

155

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

NASA Astrophysics Data System (ADS)

A new series of Er3+:Yb3+ co-doped Lithium telluroborate glasses were prepared following the melt quenching technique. The structural analyzes were made through XRD, Raman, FTIR spectra to explore the different vibrations of borate and tellurite network. The absorption spectra have been used to determine the nature of the metal-ligand and further Band gap and Urbach's analysis have also been carried out. The oscillator strength value of the 2H11/2?4I15/2 hypersensitive transition is found to be higher and increases as the concentration of the RE ion increases which emphasis the asymmetry nature of the glasses. The magnitude of the JO intensity parameters follow the trend as ?2>?4>?6 uniformly for all the prepared glasses. A bright green emission corresponding to the 2H11/2+4S3/2? 4I15/2 transition and luminescence from 4I13/2?4I15/2 in eye safe region have also been observed. The radiative parameters such as radiative transition probability, stimulated emission cross-section, branching ratios, radiative lifetime, gain bandwidth and gain linewidth for the 4S3/2 and 4I13/2 level of the title glasses have also been determined. The absorption and emission cross-section corresponding to the 4I13/2 level has been calculated using McCumber theory. Lifetime measurements were made under 980 nm excitation and the quantum efficiency were also calculated to evaluate the appropriateness of the host matrix for the fabrication of laser materials and broad band amplifiers.

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

2015-01-01

156

Photosensitivity of germanium-doped silica glass and fibers  

NASA Astrophysics Data System (ADS)

Germanium-doped silica glass changes its refractive index when it is exposed with UV light. This effect is caused by intrinsic defects of germanosilicate glass called germanium oxygen-deficient centers (GODC). The photosensitivity of glass allows fabrication of various refractive-index gratings in germanosilicate optical fibers. These gratings are basic elements used by the telecommunication industry. Nevertheless, the physical mechanisms causing the index change in glass are still unclear. In this thesis we discuss some aspects of the photosensitivity of germanium-doped glass and optical fibers. First, we present a historic overview of the previous work on defects in glass and their role for photosensitivity. The photoionization and densification theories of photosensitivity are reviewed. We then consider the transformations of defects in glass caused by UV radiation. We show that an index change can be produced by exciting either 240-nm or 330-nm absorption bands of GODC. We prove that the excitation of GODC to their triplet state is essential to produce a change in the glass structure. We also show that UV radiation forms a new defect with a luminescence band at 650 nm. We study the nature of the increase in glass photosensitivity caused by saturating glass with molecular hydrogen before exposing it to UV light. Hydrogen-loading the glass increases the saturated value of its index change by at least an order of magnitude and allows the use of high-coherence lasers at 275-305 nm for efficient and high-precision fiber grating fabrication. We also show that the stability of the refractive index change in hydrogen-loaded fibers is correlated with the water content of the glass. The difference between the spectral dependencies of photosensitivity in hydrogen-loaded and hydrogen-free glass suggests that different mechanisms are responsible for the index change in these two cases. We propose possible photoinduced reactions of hydrogen with germanium-doped glass. Finally, we analyze the properties and new applications of long-period fiber gratings. Using specially designed quadratic-dispersion gratings, we make high-sensitivity sensors with variable transmission but fixed resonant wavelength. We also present fixed-wavelength intensity modulators and bandpass filters based on long-period gratings.

Grubsky, Victor

157

Fluorescence properties of Nd3+-doped tellurite glasses.  

PubMed

The compositional and concentration dependence of luminescence of the (4)F(3/2)-->(4)I(J) (J=13/2, 11/2 and 9/2) transitions in four Nd(3+)-doped tellurite based glasses has been studied. The free-ion energy levels obtained for 60TeO(2)+39ZnO(2)+1.0Nd(2)O(3) (TZN10) glass have been analysed using the free-ion Hamiltonian model and compared with similar results obtained for Nd(3+):glass systems. The absorption spectrum of TZN10 glass has been analysed using the Judd-Ofelt theory. Relatively longer decay rates have been obtained for Nd(3+)-doped phosphotellurite glasses. The emission characteristics of the (4)F(3/2)-->(4)I(11/2) transition, of the Nd(3+):TZN10 glass, are found to be comparable to those obtained for Nd(3+):phosphate laser glasses. The non-exponential shape of the emission decay curves for the (4)F(3/2)-->(4)I(11/2) transition is attributed to the presence of energy transfer processes between the Nd(3+) ions. PMID:17027327

Kumar, K Upendra; Prathyusha, V A; Babu, P; Jayasankar, C K; Joshi, A S; Speghini, A; Bettinelli, M

2007-07-01

158

LaSr-manganate powders by crystallization of a borate glass  

Microsoft Academic Search

(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

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

2000-01-01

159

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

SciTech Connect

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

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

1985-11-01

160

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

SciTech Connect

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

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

2013-11-13

161

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

NASA Astrophysics Data System (ADS)

X-ray diffraction (XRD) and Fourier transform infrared (FTIR) spectroscopy measurements have been employed to investigate the (Gd2O3)x?(B2O3)(60-x)?(ZnO)40 glass ceramics system, with 0 ? x ? 15 mol%. After heat treatment applied at 860 °C for 2 h, some structural changes were observed and new crystalline phases appeared in the structure of the samples. In these glass ceramics four crystalline phases were identified using powder diffraction files (PDF 2), namely ZnB4O7, Zn4O(B6O12), Zn3(BO3)2 and GdBO3. From the XRD data, the average unit-cell parameter and the quantitative ratio of the crystallographic phases in the studied samples were evaluated. FTIR data revealed that the BO3, BO4 and ZnO4 are the main structural units of these glass ceramics network. The compositional dependence of the different structural units which appear in the studied samples was followed.

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

2013-11-01

162

XANES studies on Eu-doped fluorozirconate based glass ceramics  

PubMed Central

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

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

2012-01-01

163

Spectroscopic properties of lead fluoroborate glasses doped with ytterbium.  

PubMed

A new lead fluoroborate glass (PbO-PbF2-B2O3) doped with ytterbium (Yb:PbFB) is presented. Samples with different concentrations of Yb3+ were produced and had their emission cross-sections, fluorescence lifetimes and minimum pump intensities determined. They have high refractive index of 2.2 and a density of 4.4 g/cm3. For a doping level of 1.153x1020 ions/cm3, the fluorescence lifetime, after excitation at 968 nm, is 0.81 ms, which is comparable to Yb:tellurite laser glass. Also, an emission band at 1022 nm is measured with emission cross-section of approximately 1.07x10-20 cm2 and fluorescence effective linewidth of 60 nm, which is comparable to Yb:phosphate laser glass. PMID:19417856

Kassab, L; Tatumi, S; Morais, A; Courrol, L; Wetter, N; Salvador, V

2001-05-01

164

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

NASA Astrophysics Data System (ADS)

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

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

2014-11-01

165

Spectral studies of Erbium doped heavy metal borophosphate glass systems  

NASA Astrophysics Data System (ADS)

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

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

2012-02-01

166

IR and EPR studies on some lithium-borate glasses with vanadium ions  

NASA Astrophysics Data System (ADS)

The IR spectra of the xV 2O 5(100- x)[2B 2O 3·Li 2O] glasses contain the bands characteristic for B 2O 3( ?(B-O-B)=700 cm -1, ?¯(B-O)=1250 cm -1), Li 2O ( ?¯(Li-O)=415 cm -1) and V 2O 5( ?¯(V-O)=950 cm -1) groups. EPR spectra for the glasses with small contents of V 2O 5(x?5 mol%) show a well-resolved hyperfine structure typical for isolated vanadyl ions in a ligand field of near octahedral ( Oh) symmetry. For x>20 mol% the EPR spectra may be considered as a superposition of two signals: one with the resolved hyperfine structure for isolated VO 2+ ions in a C4 v symmetry and another broad line without structure at g?1.96 for associated vanadium ions. The clustered ions are due to the dipole-dipole interactions between V 4+ ions and their number increases with the V 2O 5 content. The spectroscopic studies indicate that the V 2O 5 oxide becomes a former of the network at high concentration (x>20 mol%) together with B 2O 3.

Cozar, O.; Ardelean, I.; Bratu, I.; Simon, S.; Craciun, C.; David, L.; Cefan, C.

2001-05-01

167

Pr3+-doped phosphate glasses for fiber amplifiers operating at 1.38-1.53 ?m of the fifth optical telecommunication window  

NASA Astrophysics Data System (ADS)

Effective near-infrared emission covering the fifth optical telecommunication window (1380-1525 nm) has been observed in Pr3+-doped phosphate (LCBALP) glasses. Judd-Ofelt parameters ?2 (9.17 × 10-20 cm2), ?4 (16.50 × 10-20 cm2) and ?6 (2.41 × 10-20 cm2) indicate a high inversion asymmetrical and strong covalent environment in the optical glasses. The effective bandwidth (??eff) of the corresponding 1D2 ? 1G4 transition emission is obtained to be 148 nm, and the maximum stimulated emission cross-section (?em) at 1467.5 nm is derived to be 1.29 × 10-20 cm2. The quantum efficiency of Pr3+:1D2 level is identified to be 85.36%. The broad effective bandwidth and the large emission cross-section profile indicate that Pr3+-doped LCBALP glass fiber is promising in the realization of effective broadband amplification, especially at E- and S-band. As an expectation, the mature oxide glasses with Pr3+-doping, such as borate, phosphate and silicate glasses, are expected to be attractive candidates for broadband signal amplifiers operating at the fifth optical telecommunication window.

Han, Xiaozhe; Shen, Lifan; Pun, Edwin Yue Bun; Ma, Tiecheng; Lin, Hai

2014-05-01

168

Nuclear Magnetic Resonance Structural Studies of Barium Borosilicate Glasses, Fluorine-Doped Silicate Glasses, and Glasses Containing Selenium-Oxide and Mercuric -  

Microsoft Academic Search

The study of BaO-B_2O _3-SiO_2 glasses presented in this thesis utilizes ^{11} B and ^{29}Si nuclear magnetic resonance spectroscopy in measuring directly the amounts of boron species involved in tetrahedral and trigonal units as a function of BaO and SiO_2 contents. Analysis and interpretation of the data incorporates the use of a glass structure model which quantifies all borate and

Phillip Elton Stallworth

1989-01-01

169

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

SciTech Connect

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

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

2014-04-24

170

LaSr-manganate powders by crystallization of a borate glass  

NASA Astrophysics Data System (ADS)

(LaSr)MnO 3 powders with perovskite structure were prepared in the basic system MnO 2-SrO-La 2O 3-B 2O 3 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 53 Am 2/kg, a Curie temperature between 369 and 389 K and specific surfaces of about 10 m 2/g corresponding to a mean particle size of 100 nm. The powders reveal the magneto-resistive effect.

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

2000-07-01

171

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

172

Ytterbium-doped glass-ceramics for optical refrigeration.  

PubMed

We report for the first time the characterization of glass-ceramics for optical refrigeration. Ytterbium-doped nanocrystallites were grown in an oxyfluoride glass matrix of composition 2YbF3:30SiO2-15Al2O3-25CdF2-22PbF2-4YF3, forming bulk glass-ceramics at three different crystalisation levels. The samples are compared with a corresponding uncrystalised (glass) sample, as well as a Yb:YAG sample which has presented optical cooling. The measured X-ray diffraction spectra, and thermal capacities of the samples are reported. We also report for the first time the use of Yb:YAG as a reference for absolute photometric quantum efficiency measurement, and use the same setup to characterize the glass and glass-ceramic samples. The cooling figure-of-merit was measured by optical calorimetry using a fiber Bragg grating and found to depend on the level of crystallization of the sample, and that samples with nanocrystallites result in higher quantum efficiency and lower background absorption than the pure-glass sample. In addition to laser-induced cooling, the glass-ceramics have the potential to serve as a reference for quantum efficiency measurements. PMID:25836500

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

2015-02-23

173

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

174

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

E-print Network

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

Boyer, Edmond

175

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

E-print Network

Erbium-doped transparent glass ceramic optical fibres: Characterization using mass spectroscopy) doped silica-based optical fibres with transparent glass ceramic (TGC) core were fabricated through amplifiers and laser sources. Keywordst; Optical fibres, Rare-earth-doped materials; Silica; Spectroscopy

Boyer, Edmond

176

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

E-print Network

Bose Glass of Quasiparticles in Doped Quantum Magnet Gregory S. Boebinger, National High Magnetic. This BEC can localize in the presence of disorder caused by Br- doping to form a Bose Glass. The BEC-Bose Glass (BEC-BG) transition can be carefully controlled by magnetic field, allowing us to sensitively

Weston, Ken

177

Ytterbium-doped glass waveguide laser fabricated by ion exchange  

Microsoft Academic Search

A ytterbium-doped, glass, channel waveguide laser, fabricated by ion exchange, is reported. The 2.2 cm long device, using broad-band 4% output couplers, lased in the vicinity from 1020 to 1030 nm when pumped by a Ti:sapphire laser operating at 910 nm. A lasing threshold of 50 mW (launched pump) and a slope efficiency of 5% were measured. Device parameters, including

Catalin Florea; Kim A. Winick

1999-01-01

178

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

179

Thermal and optical properties of Tm3+ doped tellurite glasses.  

PubMed

Ultraviolet, visible (UV/VIS) and differential thermal analysis (DTA) measurements were carried out in order to investigate the optical and thermal properties of various 0.5 mol.% Tm2O3 containing (1 - x)TeO2 + xLiCl glasses in molar ratio. The samples were prepared by fusing the mixture of their respective reagent grade powders in a platinum cricuble at 750 degrees C for 30 min. DTA curves taken in the 23-600 degrees C temperature range with a heating rate of 10 degrees C/min reveal a change in the value of the glass transition temperature, Tg, while melting was not observed for the glasses containing LiCl content less than 50 mol.%. These glasses were found to be moisture-resistant. However, the glasses with LiCl content higher than 50 mol.%, in which a melting peak was observed at Tc = 401 degrees C, were moisture-sensitive. Absorption measurements in the UV/VIS region of the glasses without Tm2O3 content show that the Urbach cutoff occurs at about 320 nm and, is relatively independent of the LiCl content. Six absorption bands were observed in the Tm2O3 doped glasses corresponding to the absorption of the 1G4, 3F2, 3F3 and 3F4, 3H5 and 3H4 levels from the 3H6 ground level of Tm3+ ions. The spectra also show that the integrated absorption cross-section of each band depends on the glass composition. Judd-Ofelt theory was used to determine the Judd-Ofelt parameters as well as the radiative transition probabilities for the metastable levels of Tm3+ ions in (0.3)LiCl + (0.7) TeO2: 0.01 Tm2O3 glass which is moisture-resistant. PMID:11206561

Ozen, G; Demirata, B; Oveço?lu, M L; Genç, A

2001-02-01

180

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

181

Dy(3+)-doped zinc fluorophosphate glasses for white luminescence applications.  

PubMed

Dysprosium (Dy(3+)) 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 (4)F9/2 level of 1.0 mol% of Dy2O3 doped glass. Visible luminescence spectra have been obtained due to (4)F9/2?(6)HJ (J=11/2, 13/2, 15/2) transitions of Dy(3+) ions under 385 nm excitation. The yellow-to-blue luminescence intensity ratios and chromaticity coordinates of Dy(3+) ions in these glasses have been analyzed as a function of Dy(3+) ion concentration. The decay profiles for the (4)F9/2 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 Dy(3+) ion) and acceptor (ground state Dy(3+) ion). The results reveal that these glasses emit bright white light which is suitable for the development of W-LEDs. PMID:23719414

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

2013-09-01

182

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.

2014-06-01

183

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

SciTech Connect

Graphical abstract: The blocking effect of the crystal–glass interface on the carrier transport behavior in the lanthanum doped barium strontium titanate glass–ceramics: preparation and characterization. - Highlights: • La{sub 2}O{sub 3} addition promotes the crystallization of the major crystalline phase. • The Z? and M? peaks exist a significant mismatch for 0.5 mol% La{sub 2}O{sub 3} addition. • The Z? and M? peaks separate obviously for 1.0 mol% La{sub 2}O{sub 3} addition. • Crystallite impedance decreases while crystal–glass interface impedance increases. • La{sub 2}O{sub 3} addition increases blocking factor of the crystal–glass interface. - Abstract: The microstructures and dielectric properties in La{sub 2}O{sub 3}-doped barium strontium titanate glass–ceramics have been investigated by scanning electron microscopy (SEM) and impedance spectroscopy. SEM analysis indicated that La{sub 2}O{sub 3} additive decreases the average crystallite size. Impedance spectroscopy revealed that the positions of Z? and M? peaks are close for undoped samples. When La{sub 2}O{sub 3} concentration is 0.5 mol%, the Z? and M? peaks show a significant mismatch. Furthermore, these peaks separate obviously for 1.0 mol% La{sub 2}O{sub 3} addition. With increasing La{sub 2}O{sub 3} concentration, the contribution of the crystallite impedance becomes smaller, while the contribution of the crystal–glass interface impedance becomes larger. More interestingly, it was found that La{sub 2}O{sub 3} additive increases blocking factor of the crystal–glass interface in the temperature range of 250–450 °C. This may be attributed to a decrease of activation energy of the crystallite and an increase of the crystal–glass interface area.

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

2013-10-15

184

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

E-print Network

is similar to the standard float glass widely used in the glass industry: mol. % 13Na2O­10CaO­6MgO­71SiO2Microwave response near zero magnetic field in transition-metal-doped silicate glasses R. R- and iron-doped Na2O­CaO­MgO­SiO2 glasses with phase opposite to the normal Mn 2 and Fe 3 paramagnetic

Glebov, Leon

185

Oxyfluorotellurite glasses doped by dysprosium ions. Thermal and optical properties  

NASA Astrophysics Data System (ADS)

The paper shows results of investigation of thermal and optical properties of oxyfluorotellurite (65 - x)TeO2-20ZnF2-12Pb2O5-3Nb2O5-xDy2O3 (x = 0.5, 2 and 5) glass systems. Thermal stability and the onset of crystallization of the materials were monitored by differential thermal analysis (DTA). It was found that characteristic parameters, namely glass transition temperatures (Tg), onset of crystallization temperatures (Tc) and thermal stability criteria ?T and H' increased with increasing Dy2O3 content indicating that the incorporation of dysprosium ions improves substantially thermal stability of glass system under study. Optical absorption and emission spectra of Dy3+ ions in oxyfluorotellurite glass were investigated at room temperature in the visible (VIS) and near-infrared (NIR) region. Oscillator strengths, phenomenological Judd-Ofelt (JO) intensity parameters ?2,4,6, radiative transition probabilities, branching ratios and radiative lifetimes of luminescent levels were determined. Decay curves of the 4F9/2 luminescence of incorporated Dy3+ ions were recorded and analysed. Lifetimes and the luminescence dynamics were studied as a function of the Dy2O3 concentration. It was concluded that good thermal stability combined with desirable spectroscopic parameters of investigated dysprosium-doped oxyfluorotellurite glass point at the suitability of this material for the design of UV-excited visible phosphors.

Klimesz, Barbara; Ryba-Romanowski, Witold; Lisiecki, Rados?aw

2015-04-01

186

Optical properties of Dy 3+-doped phosphate and fluorophosphate glasses  

NASA Astrophysics Data System (ADS)

Optical properties of Dy 3+-doped phosphate (P 2O 5 + K 2O + BaO + Al 2O 3) and fluorophosphate (P 2O 5 + K 2O + BaO + BaF 2 + Al 2O 3) glasses have been investigated. The observed bands in absorption spectra of 1.0 mol% Dy 3+-doped glasses have been assigned and analyzed using the parametric free-ion Hamiltonian model. Judd-Ofelt (JO) intensity parameters have been obtained from the optical absorption spectra. The sensitiveness of the ?2 JO parameter to the hypersensitive transition has been demonstrated. Using these JO parameters radiative properties of some of the excited states of Dy 3+ ions have been calculated. A strong yellow emission was observed from the 4F 9/2 ? 6H 13/2 transition of Dy 3+ ions in these glasses. The peak stimulated emission cross-section for the 4F 9/2 ? 6H 13/2 transition is found to be comparable with those of other Dy 3+: systems. The decay curves of the 4F 9/2 level have been measured and are found to deviate from exponential nature with increase in Dy 3+ ions concentration. The non-exponential decay curves have been fitted with the Inokuti-Hirayama model which revealed that dipole-dipole mechanism is responsible for the energy transfer processes through Dy 3+-Dy 3+ interactions.

Babu, S. Surendra; Babu, P.; Jayasankar, C. K.; Tröster, Th.; Sievers, W.; Wortmann, G.

2009-02-01

187

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

NASA Astrophysics Data System (ADS)

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

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

2014-08-01

188

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

NASA Astrophysics Data System (ADS)

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

Lisiecki, Rados?aw; Augustyn, El?bieta; Ryba-Romanowski, Witold; ?elechower, Micha?

2011-09-01

189

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

E-print Network

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

Hughes, M; Rutt, H; Hewak, D

2014-01-01

190

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

191

IR optical limiting in europium and thulium doped oxide glasses  

NASA Astrophysics Data System (ADS)

IR-induced two-photon absorption in PbO-Ga 2O 3-Bi 2O 3-CdO (PGBC) glasses doped by Eu 3+ and Tm 3+ rare earth (RE 3+) ions is reported. A pulsed CO laser ( ?=5.5 ?m, power density up to 3.8 GW/cm 2 per pulse) was applied as a photoinducing IR-light beam. An optical parametrical generator cut from a proustite crystal was used as a source of the fundamental TPA beam within the 3-7.5 ?m spectral range. Absolute values of the TPA coefficients were more than 13% higher compared to corresponding value for other similar glasses: As 2Te 3-CaCl 2-PbCl 2 [J. Appl. Phys. 85 (1999) 425; Phys. Rev. B 60 (1999) 942; Opt. Lasers Technol. 33 (3) (2001) 157; Mater. Lett. 54 (2002)] or Sb 2Se 3-BaCl 2-PbCl 2 [J. Mater. Sci. 35 (1) (2000) 215; Mater. Lett. 49 (2001) 272; J. Non-Cryst. Solids 297 (2002) 285]. The PGBC system possesses a shorter time response (about 12 ps), compared with other IR non-linear optical glasses. We have also established that all non-linear optical susceptibilities are crucially dependent on the type of RE 3+ ion. A maximal value of the TPA is achieved for the PGBC glasses doped by Tm 3+. The TPA values increase significantly below 45 K. We have carried out molecular dynamics and quantum chemical simulations in order to evaluate contribution of electron-phonon anharmonic interactions to the TPA.

Wasylak, J.; Ozga, K.; Kityk, I. V.; Kucharski, J.

2004-07-01

192

Synthesized rare-earth doped oxide glasses for nonlinear optics  

NASA Astrophysics Data System (ADS)

Photostimulated nonlinear optical effects in synthesized PbO-Ga2O3-Bi2O3-CdO (PGBC) glasses doped by Yb3+, Er3+, and Dy3+ rare-earth (RE3+) ions were discovered. Temperature-dependent measurements of optical photoinduced second-harmonic generation (PISHG) and two-photon absorption were performed in the infrared (IR) range. CO pulse laser (lambda=5.5 mum, energy power density up to 3.8 GW/cm2 per pulse) was applied as a source of IR-photoinducing and probing (fundamental) light. Absolute values of the PISHG were more than 22% higher than corresponding values obtained for other glasses: As2Te3-CaCl2-PbCl2 1 or Sb2Se3-BaCl2-PbCl2 2 type. The investigated PGBC system possesses a shorter time response (about 18 ps), compared with other IR nonlinear optical glasses. We have also established that all nonlinear optical susceptibilities are dependent on the type of RE3+ ion. A maximal value of the PISHG is achieved for the glasses doped by Yb3+. The PISHG values increase significantly below 25 K. We have carried out ab initio molecular dynamics and quantum chemical simulations in order to evaluate the possible contribution of electron-phonon anharmonic interactions in the observed phenomena. We have modeled the influence of the external CO photoinduced beam through the photoinduced anharmonic electron-phonon interactions. A decrease of the delaying time response is achieved. To obtain independent confirmation of the observed dependencies, we have carried out measurements of the epsilon2)(E during the external IR pumping. We have also compared the measured and theoretically calculated dependencies of the IR-induced effects.

Kityk, I. V.; Wasylak, J.; Benet, S.; Dorosz, D.; Kucharski, J.; Krasowski, J.; Sahraoui, B.

2002-09-01

193

Photoluminescence of Eu(3+)-doped glasses with Cu(2+) impurities.  

PubMed

Glasses activated with Eu(3+) ions are attractive as luminescent materials for various photonic applications. Co-doping with copper has been proposed for enhancing material optical properties, but the quenching effect of Cu(2+) impurities on Eu(3+) emission in glass remains largely unexplored. In this work, Eu2O3/CuO-containing barium-phosphate glasses have been prepared by the melt-quench method, and the Eu(3+) photoluminescence (PL) quenching resulting from Eu(3+)?Cu(2+) energy transfer was evaluated. Optical absorption spectroscopy showed that with the increase in CuO concentration the Cu(2+) absorption band resonant with Eu(3+) emission (e.g. (5)D0?(7)F2 transition around 615nm) developed steadily. As a result, Eu(3+) PL was progressively quenched. Evaluation of the quenching constants as a function of temperature in the 298-673K range showed differences basically within experimental error, consistent with a resonant transfer and lack of phonon-assisted processes. Moreover, analysis of the Eu(3+) emission decay dynamics revealed a strong correlation between the decay rates and Cu(2+) impurity levels. Results imply that for practical applications the levels of Cu(2+) in Eu(3+)/Cu(+)-activated glasses should be reduced if not removed as these will significantly limit device efficiency. PMID:25797222

Jiménez, José A

2015-06-15

194

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

NASA Astrophysics Data System (ADS)

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

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

2013-12-01

195

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

NASA Astrophysics Data System (ADS)

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

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

2014-05-01

196

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

SciTech Connect

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

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

2014-05-21

197

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

2006-07-01

198

Spectroscopic characteristics of Sm 3+-doped alkali fluorophosphate glasses  

NASA Astrophysics Data System (ADS)

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 + 19 RF + 1Sm 2O 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 ( AR), branching ratios ( ?R), lifetimes ( ?R) and integrated absorption cross-section ( ?a) for various excited levels. The predicted values of ?R and ?R from the 4G 5/2 excited level to its lower levels are compared with the experimentally measured values. Stimulated emission cross-sections ( ?e) were also determined for 4G 5/2 ? 6H 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.

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

2006-07-01

199

Pr3 + -doped GeSx-based glasses for fiber amplifiers at 1.3 µm  

NASA Astrophysics Data System (ADS)

The photoluminescence properties of Pr3+ -doped GeS x -based glasses are studied and compared with those of other sulfide and fluoride glasses. The possibility of highly pump-power-efficient fiber amplifiers based on these GeSx-containing glasses in the telecommunications window at 1.3 mu m is discussed.

Simons, D. R.; Faber, A. J.; de Waal, H.

1995-03-01

200

Index matching between passive and active tellurite glasses for use in microstructured fiber lasers: erbium doped lanthanum-tellurite glass.  

PubMed

Active and passive variants of La-containing tellurite glasses have been developed with matched refractive indices. The consequences of adding lanthanum to the glass was studied through measurements of the crystallization stability, glass viscosity and the loss of unstructured fibers. Doping the glass with erbium allowed for any spectroscopic changes to be observed through measurements of the absorption and energy level lifetimes. The fluorescence emission spectra were measured at 1.5 microm and, to the best of our knowledge, for the first time in tellurite glass at 2.7 microm. PMID:19724556

Oermann, Michael R; Ebendorff-Heidepriem, Heike; Li, Yahua; Foo, Tze-Cheung; Monro, Tanya M

2009-08-31

201

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

202

Laser beam irradiation of silver doped silicate glasses  

NASA Astrophysics Data System (ADS)

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

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

2010-10-01

203

Synthesis and Structural Characterization of Niobium Doped Lead-Telluride Glass-Ceramics  

NASA Astrophysics Data System (ADS)

The basic glasses with composition (70-x) TeO2-30PbO-xNb2O5 (where x=0.1 mol % and 0.2 mol %) were prepared by melt quenching method and heat treated at 280°C for 30 min. The samples becoming glass ceramics was confirmed by SEM. The XRD parameters such as crystallite size of these glass ceramics decreases as increase the impurity and is the order of 184-109A°. However, micro strain (?) and dislocation density (?) increases. Glass transition and thermal stability estimated from DSC measurements and it has been found that both increase with increasing of impurity. Infrared Absorption spectra were measured for TeO2 glass and glass ceramic doped with Nb2O5. The recorded bands attributed to the different modes of vibration and stretching of Te-O band. Optical Absorption spectra of TeO2-PbO- Nb2O5 system shows that the absorption edge has a tail extending towards the lower energies and shifts towards for higher energies for rare earths-doped glass-ceramics. The degree of the edge shift was found to depend on the structural rearrangement and the relative concentrations of the glass basic units. The general appearance of the absorption spectra of these rare earth doped TeO2 glasses are similar to the spectra observed for other glasses doped with the same kind of rare earth oxides.

Sathish, M.; Eraiah, B.

2015-02-01

204

Gamma-ray attenuation coefficients in some heavy metal oxide borate glasses at 662 keV  

Microsoft Academic Search

The linear attenuation coefficient (mu) and mass attenuation coefficients (mu\\/rho) of glasses in three systems: xPbO(1-x)B2O3, 0.25PbO.xCdO(0.75-x)B2O3 and xBi2O3(1-x)B2O3 were measured at 662 keV. Appreciable variations were noted in the attenuation coefficients due to changes in the chemical composition of glasses. In addition to this, absorption cross-sections per atom were also calculated. A comparison of shielding properties of these glasses

A. Khanna; S. S. Bhatti; K. J. Singh; K. S. Thind

1996-01-01

205

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

NASA Astrophysics Data System (ADS)

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

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

2014-11-01

206

Fluorescence characteristics and energy transfer of ytterbium-sensitized erbium-doped fluorophosphate glass for amplifier applications  

NASA Astrophysics Data System (ADS)

Yb3+/Er3+ codoped fluorophosphate glass has been investigated for developing broadband waveguide amplifier application. Spectroscopic properties and energy transfer microparameters of prepared glasses have been discussed. The spectral components of 1.55 ?m emission are analyzed and an equivalent four-level system is proposed to estimate the stark splitting for the 4I15/2 and 4I13/2 levels in Er3+ doped fluorophosphate glass. The results indicate that highly doped Yb3+ ions could transfer energy to Er ions efficiently in fluorophosphate glass and Er3+/Yb3+ doped fluorophosphate glass is preferable for broadband Er3+-doped waveguide amplifier application.

Tian, Ying; Wei, Tao; Chen, Fangze; Jing, Xufeng; Zhang, Junjie; Xu, Shiqing

2014-01-01

207

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

SciTech Connect

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

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

2011-01-24

208

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

NASA Astrophysics Data System (ADS)

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

Nogata, Kohei; Suzuki, Takenobu; Ohishi, Yasutake

2013-09-01

209

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

210

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

PubMed

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

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

2014-01-01

211

Gamma-ray attenuation coefficients in some heavy metal oxide borate glasses at 662 keV  

Microsoft Academic Search

The linear attenuation coefficient (?) and mass attenuation coefficients (??) of glasses in three systems: xPbO(1 ? x)B2O3, 0.25PbO · xCdO(0.75 ? x)B2O3 and xBi2O3(1 ? x)B2O3 were measured at 662 keV. Appreciable variations were noted in the attenuation coefficients due to changes in the chemical composition of glasses. In addition to this, absorption cross-sections per atom were also calculated.

Atul Khanna; S. S. Bhatti; K. J. Singh; K. S. Thind

1996-01-01

212

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

NASA Technical Reports Server (NTRS)

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

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

1997-01-01

213

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

NASA Astrophysics Data System (ADS)

Chalcogenide glasses have wide applications in optical device technology. But it has some disadvantages like thermal instability. Among them Tellurite glasses exhibits high thermal Stability. Doping of rare earth elements into the Tellurite glasses improve its optical properties. To improve its mechanical properties composites of this Tellurite glasses with polymer are prepared. Bulk samples of Er2O3 doped TeO2-WO3-La2O3 Tellurite glasses are prepared from high purity oxide mixtures, melting in an alumina crucible in air atmosphere. Composites of this Tellurite glasses with polymer are prepared by powder mixing method and the thin films of these composites are prepared using polymer press. Variations in band gap of these composites are studied from the UV/Vis/NIR absorption.

Sushama, D.

2014-10-01

214

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

NASA Astrophysics Data System (ADS)

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

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

2012-04-01

215

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

SciTech Connect

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

Sushama, D., E-mail: sushasukumar@gmail.com [Research Awardee, LAMP, Dept. of Physics, Nit, Calicut, India and Dept. of Physics, M.S.M. College, Kayamkulam, Kerala (India)

2014-10-15

216

Electron Spin Resonance measurements on Er-doped chalcogenide glasses  

NASA Astrophysics Data System (ADS)

Er doped Ge_33As_12Se_55 bulk glasses were studied by X-band electron spin resonance (ESR) measurements at low temperatures. The Er-related ESR signal is very broad, with intensity from zero magnetic field to higher than 1.4 T. At low field a relatively narrow peak exists at g \\cong 13.5 with a low field wing extended to zero field. The low field wing is due to the hyperfine structure arising from the isotope ^167Er with nuclear spin I=7/2, which is 22.9% abundant. As is the case in most crystalline hosts, the Er ESR line becomes broader with increasing temperature. Simulation of the powder pattern shows that the main peak at low field results from g_? \\cong 13.5. The high field part of the ESR spectrum is very broad and featureless and corresponds to values of g_allel that approach 0.5. This measurement is the first accurate evaluation of the spin-Hamiltonian parameters for Er in a glassy host. The Er ESR spectrum results from distortions due to the disorder in the host matrix. A second ESR signal was observed at around g=2. A line-shape analysis indicates that this signal mainly comes from an As-related defect with g_allel = 2.0023, g_? = 2.066; A_allel = 200 Gauss, A_? = 50 Gauss.

Yan, Baojie; Taylor, P. C.

1997-03-01

217

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

218

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

Microsoft Academic Search

Oxyfluoride transparent glass–ceramics combine some features of glasses (easier shaping or lower than single crystals cost of fabrication) and some advantages of rare-earth doped single crystals (narrow absorption\\/emission lines and longer lifetimes of luminescent levels). Since the material seems to be promising candidate for efficient fiber amplifiers, the manufacturing as well as structural and optical examination of the oxyfluoride glass–ceramic

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

219

Optical absorption and near infrared emissions of Nd3+ doped fluorophosphate glass.  

PubMed

Fluorophosphate glass doped with Nd(3+) has been synthesized with low OH content. Near infrared emissions centered around 0.9, 1.06, and 1.3 ?m have been successfully obtained in present glass excited by a conventional 800 nm laser diode. Based on the absorption spectrum, radiative properties were calculated and discussed using the Judd-Ofelt theory. The luminescence characteristics and energy transfer mechanism were investigated. Desirable low OH(-) concentration and spectroscopic characteristics of Nd(3+)-doped fluorophosphate glass indicate that it is a promising material for near-infrared lasers. PMID:22995468

Tian, Ying; Zhang, Junjie; Jing, Xufeng; Xu, Shiqing

2012-12-01

220

Optical absorption and near infrared emissions of Nd3+ doped fluorophosphate glass  

NASA Astrophysics Data System (ADS)

Fluorophosphate glass doped with Nd3+ has been synthesized with low OH content. Near infrared emissions centered around 0.9, 1.06, and 1.3 ?m have been successfully obtained in present glass excited by a conventional 800 nm laser diode. Based on the absorption spectrum, radiative properties were calculated and discussed using the Judd-Ofelt theory. The luminescence characteristics and energy transfer mechanism were investigated. Desirable low OH- concentration and spectroscopic characteristics of Nd3+-doped fluorophosphate glass indicate that it is a promising material for near-infrared lasers.

Tian, Ying; Zhang, Junjie; Jing, Xufeng; Xu, Shiqing

2012-12-01

221

Fabrication of F-Doped Silica Glasses by the Sol-Get Method  

NASA Astrophysics Data System (ADS)

Fluorine-doped silica glasses have been successfully fabricated by the sol-get method. Fluorine was incorporated into dry gels during the sintering process under an inert gas flow containing SF6. The F-content in the silica glasses strongly depends on the get property, especially on the specific surface area. The maximum minus relative index difference of the F-doped silica glass made from the dry gets is 1.5 times greater than that made from the VAD soot.

Shibata, Shuichi; Kitagawa, Takeshi; Hanawa, Fumiaki; Horiguchi, Masaharu

1986-11-01

222

Theory of the Bose-glass states in Br-doped Nickel-Tetrakis Thiourea (DTN)  

NASA Astrophysics Data System (ADS)

We present extensive Quantum Monte Carlo calculations on bond-disordered coupled spin chains with strong single-ion anisotropy, modeling the behavior of Br-doped Nickel-Tetrakis Thiourea (DTN). Our model quantitatively describes the phase diagram of the experimental compound - in particular the low-temperature magnetization curve and the critical temperature for magnetic Bose-Einstein condensation as a function of the field. Hence it provides fundamental insight into the nature of the Bose-glass phases appearing at low temperature close to the two critical fields for condensation. Br-doped bonds act as nucleation centers of magnetic quasiparticles in the low-field Bose glass, while at high fields the Br-doped bonds represent the localization centers of magnetic quasiholes. The quantitative understanding of Br-doped DTN opens the way to a detailed investigation of Bose-glass physics in quantum magnets.

Yu, Rong; Haas, Stephan; Roscilde, Tommaso

2011-03-01

223

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

NASA Astrophysics Data System (ADS)

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

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

2014-12-01

224

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

NASA Astrophysics Data System (ADS)

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

Veeranna Gowda, V. C.

2015-01-01

225

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

NASA Astrophysics Data System (ADS)

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

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

2014-11-01

226

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

NASA Astrophysics Data System (ADS)

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

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

2015-03-01

227

Structure and properties 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 2O 3, CeO 2, Nd 2O 3, Gd 2O 3 and Y 2O 3) of 1 mol% 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 viscosity of glass melts were measured by the rotating crucible viscometer, the melting temperature of the studied glasses were derived on the basis of Arrhenius Equation, moreover the density, bending strength and molar volume were measured and calculated. The effect of rare-earth dopants on the structure of soda-lime-silicate was analyzed by a shift of peak position and variation in the full-width at half-maximum. The effect of doping rare-earth oxides into glass on the viscosity, density and bending strength was interpreted by changing in structure of soda-lime-silicate glasses doped with rare-earth oxides.

Wang, Mi-tang; Cheng, Jin-shu; Li, Mei; He, Feng

2011-01-01

228

Electron transport studies in single transition metal ions doped borophosphate glasses  

NASA Astrophysics Data System (ADS)

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

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

2009-07-01

229

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

230

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

231

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

NASA Astrophysics Data System (ADS)

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

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

2012-01-01

232

Manifestation of microinhomogenous structure of doped fluorophosphate glasses in ?-induced optical spectra  

NASA Astrophysics Data System (ADS)

One of the main problems that should be solved to design prospective materials as fluorophosphates glasses for optical fiber amplifiers is spatial distribution of rare-earth ions in glass matrix. Doped fluorophosphate glasses 5 Ba(P0 3) II 95 MgCaSrBaA1 IIF 14 compositions are studied by means of ?-induced ESR and optical absorption spectra. Analysis of radiation center behavior in these glasses makes it possible to elucidate local environment composition of small concentration of RE-ions.

Bocharova, Tatyana V.; Karapetyan, Garegin O.; Tagil'tseva, Natal'ya O.; Vlasova, Anna N.

2007-04-01

233

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

PubMed

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

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

2010-02-01

234

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

NASA Astrophysics Data System (ADS)

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

Sasikala, T.; Rama Moorthy, L.

2014-11-01

235

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

PubMed Central

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

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

2007-01-01

236

Spectroscopic investigations on ?-irradiated Eu3+ and Dy3+ doped oxyfluoride glasses  

NASA Astrophysics Data System (ADS)

Changes in the UV-visible spectra of undoped and Dy/Eu singly doped oxyfluoride glasses with varying PbF2/CdF2 content were studied under high doses of gamma irradiation. The unirradiated undoped and doped glasses exhibited strong UV absorption and characteristic absorption bands due to the presence of rare earth ions. Gamma irradiation caused loss of transmission and red shift in the cut-off wavelength for the undoped and doped samples. The radiation induced absorption coefficient and energy band gap depicted variation due to the nature of rare earth as well as the host matrix. The rare earth addition affected the physical properties (density, refractive index, molar volume) and the structure of the studied glasses revealed by Fourier Transform Infrared Spectroscopy.

Sharma, G.; Bagga, R.; Cemmi, A.; Falconieri, M.; Baccaro, S.

2015-03-01

237

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

SciTech Connect

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

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

2010-01-01

238

Determining the 6Li Doped Side of a Glass Scintillator for Ultra Cold Neutrons  

E-print Network

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

Jamieson, Blair

2015-01-01

239

Optical properties of Er 3+ doped alkali chlorophosphate glasses for optical amplifiers  

NASA Astrophysics Data System (ADS)

A new class of Erbium doped glasses with compositions xNa 2O-(60 - x) PbCl 2-40P 2O 5 ( x = 0, 10, 20 and 30) were fabricated and characterized for optical properties. Absorption spectra were analyzed for important Judd-Ofelt parameters from the integrated intensities of various Er 3+ absorption bands. A systematic correlation between the Judd-Ofelt parameter ?2 and the covalent nature of the glass matrix was observed, due to the increased role of bridging oxygens in the glass network. Photoluminescence (PL) and its decay behavior studies were carried out for the transition 4I 13/2 ? 4I 15/2. The PL broadness and life times were typically in the range of 40-60 nm and 2.13-2.50 ms, respectively. These glasses show high transparency, high refractive index, shorter life times and, most importantly, these glasses were capable of being doped with larger concentrations of Er 3+ (up to 4 wt%). Optical performance of these doped phosphate glasses suggesting the suitability of these glasses for optical fibre/waveguide amplifiers.

Pradeesh, K.; Oton, C. J.; Agotiya, V. K.; Raghavendra, M.; Prakash, G. Vijaya

2008-10-01

240

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

SciTech Connect

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

Liu Hao [Key Laboratory for Silicate Materials Science and Engineering of Ministry of Education, Wuhan University of Technology, Wuhan, Hubei 430070 (China); Liu Qiming [Key Laboratory for Silicate Materials Science and Engineering of Ministry of Education, Wuhan University of Technology, Wuhan, Hubei 430070 (China); Zhao Xiujian [Key Laboratory for Silicate Materials Science and Engineering of Ministry of Education, Wuhan University of Technology, Wuhan, Hubei 430070 (China)]. E-mail: zhaoxj@public.wh.hb.cn

2007-01-15

241

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

NASA Astrophysics Data System (ADS)

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

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

2014-03-01

242

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

PubMed Central

The structure/property relationships of fluorochlorozirconate glass ceramics as a function of divalent and trivalent europium (Eu) co-doping and thermal processing have been investigated; the influence of doping ratio on the formation of barium chloride (BaCl2) nanocrystals therein was elucidated. X-ray absorption near-edge structure spectroscopy shows that the post-thermal annealing changes the Eu valence of the as-poured glass slightly, but during the melting process Eu3+ is more strongly reduced to Eu2+, in particular, when doped as a chloride instead of fluoride compound. The Eu2+-to-Eu3+ doping ratio also plays a significant role in chemical equilibrium in the melt. X-ray diffraction measurements indicate that a higher Eu2+ fraction leads to a BaCl2 phase transition from hexagonal to orthorhombic structure at a lower temperature. PMID:22275772

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

2011-01-01

243

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

SciTech Connect

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

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

2011-12-01

244

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

SciTech Connect

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

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

2012-10-10

245

International Workshop on Photonics and Applications. Hanoi, Vietnam. April 5-8, 2004 Wavelength shifts in Erbium doped glass microspherical  

E-print Network

Wavelength shifts in Erbium doped glass microspherical Whispering Gallery Mode lasers Carole Arnaud, Mohamed13/2 4 I15/2 transition of Er3+ ions around 1550 nm in microspheres fabricated with Erbium doped fluoride "ZBLALiP" and phosphate "Schott" glasses. The microsphere lasers have been studied under pumping

Paris-Sud XI, Université de

246

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

E-print Network

1251 Magnetic-field effect on the phonon echoes in a rare-earth-doped glass F. Lerbet and G field increases from 0 to 60 kOe. Relaxation of the tunnelling states by the rare-earth ions.50K Photon echoes in a rare-earth-doped glass have shown that the optical dephasing rates are enhanced

Boyer, Edmond

247

Spectroscopic properties of Tm3+/Al3+ co-doped sol-gel silica glass  

NASA Astrophysics Data System (ADS)

Tm3+/Al3+ co-doped silica glass was prepared by sol-gel method combined with high temperature sintering. Glasses with compositions of xTm2O3-15xAl2O3-(100 - 16x) SiO2 (in mol%, x = 0.1, 0.3, 0.5, 0.8 and 1.0) were prepared. The high thulium doped silica glass was realized. Their spectroscopic parameters were calculated and analyzed by Judd-Ofelt theory. Large absorption cross section (4.65 × 10-21 cm2 at 1668 nm) and stimulated emission cross section (6.00 × 10-21 cm2 at 1812 nm), as well as low hydroxyl content (0.180 cm-1), long fluorescence lifetime (834 ?s at 1800 nm), large ?em × ?rad (30.05 × 10-21 cm2 ms) and large relative intensity ratio of the 1.8 ?m (3F4 ? 3H6) to 1.46 (3H4 ? 3F4) emissions (90.33) are achieved in this Tm3+/Al3+ co-doped silica glasses. According to emission characteristics, the optimum thulium doping concentration is around 0.8 mol%. The cross relaxation (CR) between ground and excited states of Tm3+ ions was used to explain the optimum thulium doping concentration. These results suggest that the sol-gel method is an effective way to prepare Tm3+ doped silica glass with high Tm3+ doping and prospective spectroscopic properties.

Wang, Xue; Lou, Fengguang; Wang, Shikai; Yu, Chunlei; Chen, Danping; Hu, Lili

2015-04-01

248

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

NASA Astrophysics Data System (ADS)

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

Shahin, David I.

249

Upconversion studies in Tm, Ho co-doped alumino-zirco-fluoride glass  

Microsoft Academic Search

Tm, Ho co-doped alumino-zirco-fluoride (AZF) glass is an attractive candidate for an optical pre-amplifier around two microns. In Tm, Ho doped materials, however, upconversion from the upper laser levels of Tm 3F4 and Ho 5I7 occurs which reduces the gain coefficient and efficiency. Therefore it is important to determine the upconversion rate constants in order to estimate optimum performance of

M. Doshida; K. Teraguchi; M. Obara; K. Ota; H. Saito

1994-01-01

250

Rare-earth doped transparent nano-glass-ceramics: a new generation of photonic integrated devices  

NASA Astrophysics Data System (ADS)

We report on optical properties and prospect applications on rare-earth doped oxyfluoride precursor glass and ensuing nano-glass-ceramics. We find out the spectral optical gain of the nano-glass-ceramics and show that its flatness and breadth are advantageous as compared to contemporary used erbium doped optical amplifiers. We present the possibility of flat gain cross-section erbium doped waveguide amplifiers as short 'chip', all-optical, devices capable of dense wavelength division multiplexing, including the potential for direct writing of these devices inside bulk glasses for three-dimensional photonic integration. We carried out a comparative study of the up-conversion luminescence in Er 3+-doped and Yb 3+-Er 3+-Tm 3+ co-doped samples, which indicates that these materials can be used as green/red tuneable up-conversion phosphors and white light simulation respectively. Observed changes in the spectra of the up-conversion luminescence provide a tool for tuning the colour opening the way for producing 3-dimensional optical recording.

Rodríguez-Armas, Vicente Daniel; Tikhomirov, Victor K.; Méndez-Ramos, Jorge; Yanes, Angel C.; Del-Castillo, Javier; Furniss, David; Seddon, Angela B.

2007-05-01

251

Synthesis and characterization of cerium-doped glasses and in vitro evaluation of bioactivity  

Microsoft Academic Search

The results of preparation, characterization and in vitro bioactivity evaluation of phosphosilicate glasses based on Bioglass® 45S5 (SiO2 45; Na2O 24.5; CaO 24.5; P2O5 6 wt%) doped during melting with (1.5–13.5 wt%) cerium dioxide (CeO2), has been reported. The choice of cerium was related to its low toxicity associated with bacteriostatic properties; cerium-doped bioactive glasses could be useful when implantation

C. Leonelli; G. Lusvardi; G. Malavasi; L. Menabue; M. Tonelli

2003-01-01

252

Physical and optical properties of Pr6O11 doped zinc fluoroborate glass  

NASA Astrophysics Data System (ADS)

Praseodymium (Pr3+) doped zinc fluoroborate glasses with the chemical composition [(mol%)30ZnF2-20TeO2-(50-x)B2O3-xPr6O11] (where x = 0.0, 0.1, 0.5, 1.0 and 1.5 mol %) have been prepared by conventional melt quenching technique. The physical and optical parameters like density, refractive index, molar volume, and oscillator strength of these glasses were calculated as a function of dopant concentration. The densities and refractive indices of these glasses were found to be in the range 2 g/cm3 - 2.67 g/cm3 and 1.644 - 1.73 respectively. Stability of glass doped with 1 mol % of Pr3+ was found to be 120.

PrajnaShree, M.; Wagh, Akshatha; Raviprakash, Y.; Bhat, Sangeetha G.; Kamath, Sudha D.

2013-06-01

253

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

PubMed

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

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

2008-11-01

254

Comparative investigation on the spectroscopic properties of Pr³?-doped boro-phosphate, boro-germo-silicate and tellurite glasses.  

PubMed

We report on the spectroscopic properties of Pr(3+)-doped boro-phosphate, boro-germo-silicate and tellurite glasses. The stimulated absorption and emission cross sections were estimated. Only one emission at 596 nm and 605 nm is observed in Pr(3+)-doped boro-phosphate and boro-germo-silicate glasses, respectively, while three emissions at 605 nm, 612 nm and 645 nm are observed in Pr(3+)-doped tellurite glass when excited at 467 nm. The fluorescence lifetime at 600 nm in Pr(3+)-doped boro-phosphate, boro-germo-silicate and tellurite glasses is 137 ?s, 73 ?s and 51 ?s, respectively. The emissions from Pr(3+)-doped boro-phosphate, boro-germo-silicate and tellurite glasses show different decay behaviors and can be well explained by multiphonon relaxation theory. PMID:22484255

Zhang, Liaolin; Dong, Guoping; Peng, Mingying; Qiu, Jianrong

2012-07-01

255

[Molecular aggregation and spectrum properties of stilbene 3 doped lead-tin-fluorophosphate glass].  

PubMed

Lead-tin-fluorophosphate (PTFP) glasses with different concentrations of organic dye stilbene 3 were prepared by low temperature melting. The molecular aggregation and spectrum properties of stilbene 3 doped lead-tin-fluorophosphate glass were studied by means of emission spectra, excitation spectra and absorption spectra measurements. The results show that stilbene 3 dimers coexist with its monomers in inorganic glass. Compared with the excitation peak of stilbene 3 monomer, the excitation peak of stilbene 3 dimer is in the range of shorter wave band. As the concentration of stilbene 3 in the doped PTFP glass increased, the emission peak was red shifted and the concentration quenching of stilbene 3 was observed in the emission spectra. Compared stilbene 3 in PTFP glass with that in ethanol, a remarkable red shift of the absorption and emission spectra in the glass was found. The phenomenon is explained by the bond effect between stilbene 3 and matrix glass by hydrophilic interaction. And a much higher fluorescence intensity of stilbene 3 in the inorganic glass than that in ethonal is attributed to the "cage" effect. PMID:18536395

He, Xiao-Ling; Gu, Mu; Zhao, Zhi-Wei; Huang, Shi-Ming; Liu, Xiao-Lin; Liu, Bo; Ni, Chen; Ouyang, Xiao-Ping

2008-03-01

256

Spectroscopic study of chromium-doped transparent calcium germanate glass-ceramics  

NASA Astrophysics Data System (ADS)

The optical properties of transparent chromium-doped glass-ceramics with the chemical composition similar to that of cunyite (Cr 4+:Ca 2GeO 4) laser crystal were investigated. Room and low temperature absorption, excitation, fluorescence and Raman spectroscopy, as well as lifetime measurements were used to develop a model for the optical centers in the glass and nanocrystals. Parent (as quenched) glass does not exhibit any fluorescence; after the heat treatment Cr 4+ fluorescence band appears at ˜1280 nm. Optical properties of nanocrystals formed in the glass-ceramics differ from those in the bulk single crystal Ca 2GeO 4. By comparison of Ca 2GeO 4 - like glass-ceramics with the Ca 2GeO 4 bulk single crystals and Mg 2SiO 4 - glass-ceramics we concluded that the nanocrystal phase is a modified Ca 2GeO 4 structure. Broadband fluorescence and a high quantum efficiency of new glass-ceramics make the new Cr-doped glass-ceramics promising medium for fiber lasers and amplifiers.

Sharonov, M. Yu.; Bykov, A. B.; Myint, T.; Petricevic, V.; Alfano, R. R.

2007-07-01

257

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

258

[Mid-infrared emission and multiphonon relaxation in Tm3+-doped Ge-Ga-Se glasses].  

PubMed

A series of chalcogenide glasses based on the composition Ge30 Ga5 Se65 (at. %) doped with the different Tm3+ ions were synthesized by melt-quenching technique. The refractive indexes, Raman spectra, absorption spectra, near-and mid-infrared fluorescence, and lifetimes of glass samples under 800 nm laser excitation were measured. The intensity parameters omega(i) (i = 2, 4, 6), transition probabilities, branching ratios and radiative lifetimes have been predicted for Tm3+ ions in samples by using the Judd-Ofelt theory. The near-infrared emission spectra at 1.23, 1.48 and 1.8 microm were observed and their quantum efficiencies were evaluated respectively in glass doped with 1 Wt% Tm(3+)-ions under 800 nm excitation. The mid-infrared fluorescence spectra were investigated with the different Tm3+ ion concentration under 800 nm excitation. The multiphonon relaxation rate of Tm3+ : 3 H5 --> 3F4 by the measured and calculated lifetimes, and the relative parameters of W(0) and a in Ge30 Ga5 Se65 glass were evaluated. Results show that the multiphonon relaxation rates were significantly lower than other glasses due to the lower maximum phonon energy, so the selenide glasses are promising as host materials for doping by rare earth ions and for preparation of mid-infrared optical elements. PMID:20707130

Zhang, Peng-Jun; Dai, Shi-Xun; Le, Fang-Da; Peng, Bo; Xu, Tie-Feng; Nie, Qiu-Hua; Zhang, Xiang-Hua

2010-06-01

259

Erbium environment on Er-doped silica and alumino-silicate glass films: An EXAFS study  

NASA Astrophysics Data System (ADS)

Er-doped dielectric films are characterized by the emission of a photoluminescence signal at ? = 1.54 ?m, the main used in the optical telecommunications. The efficiency of the radiative emission is strongly related to the characteristics of the Er 3+ environment. Er-doped SiO 2 films (synthesized by rf-magnetron co-sputtering) and 87SiO 2:10Al 2O 3:3Na 2O silicate glass films doped with 0.5 mol% of Er (prepared by sol-gel route and subsequently doped with silver by Ag + ? Na + field-assisted solid-state ion exchange) were studied by extended X-ray absorption fine structure spectroscopy performed at Er L III-edge (Italian beamline GILDA of the ESRF). In the silica samples the Er coordinates about 4.5 O atoms at a short distance ( R = 2.07-2.13 Å), similar to the one observed in Er-doped glasses when the preparation conditions are far from the thermodynamical equilibrium. In alumino-silicate samples the first shell of atoms is formed of 5.5-7.5 O atoms at a distance of about 2.31 Å, showing a local structure similar to other Er-doped sol-gel glasses and glass-ceramics. A comparison between the first shell structure around Er ions and the different intensity of the photoluminescence emission suggests that the increase of the radiative emission upon thermal annealing is mainly related to the decrease of the defects number in the glass structure as a consequence of the annealing.

Cattaruzza, E.; Maurizio, C.; Visentin, L.; Trave, E.; Martucci, A.; Ali, S.; Battaglin, G.; Gonella, F.

2010-02-01

260

Novel approach to fabrication of highly doped nanporous glasses  

Microsoft Academic Search

The possibility of efficient modification of nanoporous glasses by supercritical fluid (SCF) impregnation of erbium and copper organometallics to pores and subsequent thermal annealing of glass is shown. Experiments demonstrate unambiguously the advantage of SCF impregnation approach over liquid impregnation -- much higher rate of impregnation and absence of residual solvents: supercritical fluid -- sc-CO2-releases through pores. It was shown

Nodar V. Bagratashvili; Vladimir K. Popov; Svetlana I. Tsypina; Alexey O. Rybaltovski; Pavel V. Chernov

2003-01-01

261

Hyperpolarized cesium ions doped in a glass material.  

PubMed

Hyperpolarized (HP) (133)Cs nuclear magnetic resonance signals were measured from borosilicate glass cell walls during optical pumping of cesium vapor at high magnetic field (9.4T). Significant signal enhancements were observed when additional heating of the cell wall was provided by intense but non-resonant laser irradiation, with integrated HP (133)Cs NMR signals and line widths varying as a function of heating laser power (and hence glass temperature). Given that virtually no Cs ions would originally be present in the glass, absorbed HP Cs atoms rarely met thermally-polarized Cs ions already at the surface; thus, spin-exchange via nuclear dipole interaction cannot be the primary mechanism for injecting spin polarization into the glass. Instead, it is concluded that the absorption and transport of HP atoms into the glass material itself is the dominant mechanism of nuclear spin injection at high temperatures-the first reported experimental demonstration of such a mechanism. PMID:25462952

Ishikawa, Kiyoshi

2014-10-17

262

Hyperpolarized cesium ions doped in a glass material  

NASA Astrophysics Data System (ADS)

Hyperpolarized (HP) 133 Cs nuclear magnetic resonance signals were measured from borosilicate glass cell walls during optical pumping of cesium vapor at high magnetic field (9.4 T). Significant signal enhancements were observed when additional heating of the cell wall was provided by intense but non-resonant laser irradiation, with integrated HP 133 Cs NMR signals and line widths varying as a function of heating laser power (and hence glass temperature). Given that virtually no Cs ions would originally be present in the glass, absorbed HP Cs atoms rarely met thermally-polarized Cs ions already at the surface; thus, spin-exchange via nuclear dipole interaction cannot be the primary mechanism for injecting spin polarization into the glass. Instead, it is concluded that the absorption and transport of HP atoms into the glass material itself is the dominant mechanism of nuclear spin injection at high temperatures-the first reported experimental demonstration of such a mechanism.

Ishikawa, Kiyoshi

2014-12-01

263

1.8 ?m emission of highly thulium doped fluorophosphate glasses  

NASA Astrophysics Data System (ADS)

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

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

2010-10-01

264

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

SciTech Connect

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

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

2012-07-15

265

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

SciTech Connect

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

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

2005-04-18

266

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

267

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

E-print Network

solar energy to electricity [1-3]. In order for PVs to play a major role in future energy generation and the spectral response of Si solar cells accounting for ~70% energy loss is one of the main factors limitingHighly efficient near-infrared quantum cutting in Ce3+ /Yb3+ co-doped chalcohalide glasses Bing Gao

Boyer, Edmond

268

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

E-print Network

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

Moshchalkov, Victor V.

269

2 ?m Emission of Ho 3+-doped fluorophosphate glass sensitized by Yb 3+  

NASA Astrophysics Data System (ADS)

Two micrometer emission of Ho 3+-doped new fluorophosphate glass sensitized by Yb 3+ upon excitation of a conventional 980 nm laser diode is reported. Based on the measured absorption spectra, the Judd-Ofelt parameters and radiative properties were calculated and discussed. For Yb 3+/Ho 3+ codoped fluorophosphate glass, the predicted spontaneous transition probability and emission cross-section of Ho 3+: 5I 7? 5I 8 reaches 73.54 s -1 and 4.66 × 10 -21 cm 2 , respectively, are much higher than other reported glasses. Larger product of emission cross-section ( ? em) and radiative lifetime ( ? rad) in the prepared glass shows the prepared glass is expected to be better laser material. In addition, the ? em and maximum gain coefficient of Ho 3+ in Yb 3+/Ho 3+ codoped fluorophosphate glass is 12.02% and 12.12% larger than those of Ho 3+ singly-doped sample, respectively. The results suggest Yb 3+/Ho 3+ fluorophosphate glass is a good candidate for efficient 2 ?m laser.

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

2010-09-01

270

[Luminescence properties of silane coupling agent modified stilbene 3 doped lead-tin-fluorophosphate glass].  

PubMed

In the present work, the SnF2 powder was modified by silane coupling agent KBM403. The Fourier transform infrared spectrum (FTIR) of the modified powder showed that KBM403 was absorbed on the surface of SnF2 particles through physical absorption besides a weak chemical absorption. Then the SnF2 powder was modified by the solution dissolved with stilbene 3. The modified SnF2 powder could improve the decentralization of stilbene 3 dopant. An organic-inorganic hybrid luminescence glass was prepared by doping the modified SnF2 powder with stilbene 3 into the low melting lead-tin-fluorophosphate (PTFP) glass. The excitation, emission and transmission (absorption) spectra were used to characterize the hybrid glass. The results showed that introducing KBM403 could improve solubility and decentralization of stilbene 3 in PTFP glass, reduce the concentration of stilbene 3 dimers, and increase the transparency and homogeneity of the glass. Meanwhile, the luminescence intensity of stilbene 3 in this hybrid glass increased evidently compared with that of the stilbene 3 doped glass. The effect was assumed to be the reduction of the quenching of luminescence from stilbene 3 dimer and the enhancement of the rigidity of stilbene 3 molecules due to the interaction between KBM403 and stilbene 3. PMID:20384113

Gu, Mu; Zhao, Zhi-Wei; Liu, Xiao-Lin; Ni, Chen; Huang, Shi-Ming; Liu, Bo; Ouyang, Xiao-Ping

2010-02-01

271

Photo-thermo-refractive glass co-doped with Nd 3+ as a new laser medium  

NASA Astrophysics Data System (ADS)

Photo-thermo-refractive (PTR) glass demonstrates refractive index change after exposure to UV radiation followed by a thermal treatment that enables recording of high efficiency holographic optical elements. This work demonstrates feasibility of function of this material as a complex optical medium which posseses both photosensitive and luminescent properties and paves a way for creation of monolythic solid state lasers where resonator components can be holographically recorded inside of a laser medium. It was found, that incorporating of Nd 3+ ions in PTR glass does not affect photosensitivity required for hologram recording. It was demonstrated that emission wavelength, spectral width, and cross section of Nd 3+ luminescence in PTR glass are typical for silicate laser glasses and Nd-doped PTR glass can be considered as a promising laser medium for monolithic solid state lasers.

Glebova, Larissa; Lumeau, Julien; Glebov, Leonid B.

2011-10-01

272

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

NASA Astrophysics Data System (ADS)

Aluminophosphate glasses belonging to the oxide system Li 2O-BaO-Al 2O 3-La 2O 3-P 2O 5, un-doped and doped with rare-earth metal ions (Ce 4+, Nd 3+, Sm 3+) 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

273

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

NASA Astrophysics Data System (ADS)

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

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

2009-01-01

274

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

NASA Astrophysics Data System (ADS)

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

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

2012-04-01

275

Visible emission of Tb 3+-Yb 3+ co-doped fluorophosphate glasses  

NASA Astrophysics Data System (ADS)

Visible lasers and amplifiers have potential applications in the fields of optical data storage, spectroscopy, biomedical and optical local area networks. In this study, Tb 3+-Yb 3+ co-doped fluorophosphate glasses were synthesized and properties of the visible emission at 0.54 µm were investigated. A upconversion excitation efficiency from Yb 3+ to Tb 3+ was studied by evaluations of a cooperative energy transfer efficiency from Yb 3+ to Tb 3+ (?CET) and a back-transfer efficiency from Tb 3+ to Yb 3+ (?BT ) which give positive and negative contribution to upconversion excitation, respectively. The ?CET was as high as 25 %, and the ?BT was less than 1 % in the fluorophosphate glass. This indicates that Tb 3+-Yb 3+ co-doped fluorophosphate glass is promising as new laser and gain media in the 0.54 ?m band.

Arai, Yusuke; Yamashita, Tatsuya; Horiguchi, Shin; Suzuki, Takenobu; Ohishi, Yasutake

2008-02-01

276

Bioactive glass in tissue engineering  

PubMed Central

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

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

2011-01-01

277

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

PubMed

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

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

2011-02-01

278

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

PubMed

Structural, spectroscopic and thermal properties of SiO?-Al?O?-Sb?O?-Na?O glass system doped with 0.2 mol% Tm?O? have been presented. Synthesis of antimony-silicate glasses with relatively low phonon energy (600 cm(-1), which implicates a small non-radiative decay rate) was performed by conventional high-temperature melt-quenching methods. The effect of SiO?/Sb?O? ratio in fabricated Tm(3+) doped glass on thermal, structural and luminescence properties was investigated. On the basis of structural investigations decomposition of absorption bands in the infrared FTIR region was performed, thus determining that antimony ions are the only glass-forming ions, setting up the lattice of fabricated glasses. Luminescence band at the wavelength of 1.8 ?m corresponding to (3)F??(3)H? transition in thulium ions was obtained under 795 nm laser pumping. It was observed that combination of relatively low phonon energy and greater separation of optically active centers in the fabricated glasses influenced in decreasing the luminescence intensity at 1800 nm. PMID:25049172

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

2015-01-01

279

Long-term results from unsaturated testing of actinide-doped DWPF and WVDP waste glasses  

SciTech Connect

Results from durability drip tests designed to simulate the unsaturated conditions in the proposed Yucca Mountain Repository are reported for two actinide-doped glasses used as model waste forms. These tests are being conducted with reference glass compositions doped with neptunium, plutonium, and americium from the Defense Waste Processing Facility (DWPF) and the West Valley Demonstration Project (WVDP), and have been ongoing for over 8 years. Solution compositions, including transuranics, have been periodically determined, and selected analyses of colloid formation and composition, glass corrosion layers, and solid alteration phases have been obtained by scanning and analytical transmission electron microscopies. The importance of integrated testing has been demonstrated, as complex interactions among the glass, the groundwater, and the sensitized stainless steel have been observed. The cumulative releases of both glass-forming and dopant elements are presented along with identification of reaction phases and their partitioning between solution and solid phases. Alteration phases, including smectite clay, iron silicates, uranium silicates, and calcium thorium phosphate, have been observed forming on the glass and stainless steel and have occasionally been found suspended in solution as colloids. Actinides, except neptunium, concentrate into alteration phases or sorb onto the stainless steel. The subsequent transport of the actinides is then controlled by these phases.

Fortner, J.A.; Bates, J.K. [Argonne National Lab., IL (United States)

1995-11-01

280

Long-term results from unsaturated testing of actinide-doped DWPF and WVDP waste glasses  

SciTech Connect

Results from drip tests designed to simulate the unsaturated conditions in the proposed Yucca Mountain Repository are reported for two actinide-doped glasses used as model waste forms. These tests are being conducted with reference glass compositions doped with neptunium, plutonium, and americium from the Defense Waste Processing Facility (DWPF) and the West Valley Demonstration Project (WVDP), and have been ongoing for over 8 years. Solution compositions, including transuranics, have been periodically determined, and selected analyses of colloid formation and composition, glass corrosion layers, and solid alteration phases have been obtained by scanning and analytical transmission electron microscopies. The importance of integrated testing has been demonstrated, as complex interactions among the glass, the groundwater, and the sensitized stainless steel have been observed. The cumulative releases of both glass-forming and dopant elements are presented along with identification of reaction phases and their partitioning between solution and solid phases. Alteration phases, including smectite clay, iron silicates, uranium silicates, and calcium thorium phosphate, have been observed forming on the glass and stainless steel and have occasionally been found suspended in solution as colloids. Actinides, except neptunium, concentrate into alteration phases or sorb onto the stainless steel. The subsequent transport of the actinides is then controlled by these phases.

Fortner, J.A.; Bates, J.K.

1995-12-31

281

in "Properties, Processing and Applications of Glass and Rare Earth-Doped Glasses for Optical Fibres" ed. D. Hewak, INSPEC, The Institution of Electrical Engineers, London, UK, 1998.  

E-print Network

of Silica Fibres M. J. Matthewson May 1998 A INTRODUCTION The total length of silica optical fibre now optical fibres n a 2n i f Bt , (1) where B and n are fatigue parameters that are determinedin "Properties, Processing and Applications of Glass and Rare Earth-Doped Glasses for Optical

Matthewson, M. John

282

Performance of Er3+-doped chalcogenide glass MOF amplifier applied for 1.53 ?m band  

NASA Astrophysics Data System (ADS)

A model of Er3+-doped chalcogenide glass (Ga5Ge20Sb10S65) microstructured optical fiber (MOF) amplifier under the excitation of 980 nm is presented to demonstrate the feasibility of it applied for 1.53 ?m band optical communications. By solving the Er3+ population rate equations and light power propagation equations, the amplifying performance of 1.53 ?m band signals for Er3+-doped chalcogenide glass MOF amplifier is investigated theoretically. The results show that the Er3+-doped chalcogenide glass MOF exhibits a high signal gain and broad gain spectrum, and its maximum gain for small-signal input (-40 dBm) exceeds 22 dB on the 300 cm MOF under the excitation of 200 mW pump power. Moreover, the relations of 1.53 ?m signal gain with fiber length, input signal power and pump power are analyzed. The results indicate that the Er3+-doped Ga5Ge20Sb10S65 MOF is a promising gain medium which can be applied to broadband amplifiers operating in the third communication window.

Zheng, Yuan-hui; Zhou, Ya-xun; Yu, Xing-yan; Qi, Ya-wei; Peng, Sheng-xi; Wu, Li-bo; Yang, Feng-jing

2014-05-01

283

Nd3+, Yb3+ and Nd3+/Yb3+: doped borosilicate glasses for luminescent thermometry  

NASA Astrophysics Data System (ADS)

The article presents influence of temperature on luminescent properties of borosilicate glasses with molar composition: SiO2-B2O3-Al2O3-Na2O-K2O doped with Nd3+, Yb3+ and co-doped with Nd3+/Yb°3+ ions. In the range from 60 to 300°C the quenching of luminescence signal versus increase of temperature was observed. In case of glasses doped with Nd3+ and Yb3+ ions the sensitivity was determinated to be 0.0016 [1/K] at 1.06?m and 0.001 [1/K] at 1.02?m, respectively. Fabricated glass co-doped with Nd3+/Yb3+ ions is characterized by the highest sensitivity and maximum value 0.003 [1/K] was observed at the wavelength of 1020nm, corresponding to the Yb3+: 2F5/2 --> 2F7/2 transition in energy levels structure of ions.

Bykowski, Kamil; Bruszewski, Artur; Cimaszewski, Dominik; Zmojda, Jacek; Kochanowicz, Marcin; Dorosz, Dominik

2014-11-01

284

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

NASA Astrophysics Data System (ADS)

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

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

2014-11-01

285

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

NASA Astrophysics Data System (ADS)

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

Czerska, E.; ?widerska, M.

2014-11-01

286

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

NASA Astrophysics Data System (ADS)

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

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

2013-11-01

287

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

E-print Network

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

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

2015-01-01

288

Theory of magnetic Bose glass in Br-doped dichloro-tetrakis-thiourea-nickel (DTN)  

NASA Astrophysics Data System (ADS)

We will review here the microscopic model allowing to describe quantitatively the physics of Br-doped DTN. The magnetic Hamiltonian of Br-DTN describes S=1 spins coupled through bimodally distributed antiferromagnetic bonds, and with a correlated bimodal distribution of single-ion anisotropies. A spin-boson mapping leads to a description in terms of a Bose-Hubbard-like model with random hoppings and random on-site interactions for magnetic quasiparticles, whose density is controlled by the applied magnetic field. This model features an extended gapless and compressible Bose-glass phase in low fields, extending down to zero field, at which the compressibility vanishes, corresponding to a Mott-glass phase. We will present extensive quantum Monte Carlo results for the thermodynamic signatures of the Bose glass, and for the quantum critical signatures of the magnetic ordering transition occurring at stronger field, which corresponds to a remarkable realization of the Bose-glass/superfluid transition.

Haas, Stephan; Yu, Rong; Roscilde, Tommaso

2012-02-01

289

Intense upconversion luminescence in ytterbium-sensitized thulium-doped novel oxychloride bismuth germanium glass  

NASA Astrophysics Data System (ADS)

Structural and up-conversion fluorescence properties in ytterbium-sensitized thulium-doped novel oxychloride bismuth-germanium glass have been studied. The structure of novel bismuth-germanium glass was investigated by peak-deconvolution of Raman spectrum, and the structural information was obtained from the peak wave numbers. The Raman spectrum investigation indicates that PbCl 2 plays an important role in the formation of glass network, and has an important influence on the up-conversion luminescence. Intense blue and weak red emissions centered at 477 and 650 nm, corresponding to the transitions 1G 4? 3H 6 and 1G 4? 3H 4, respectively, were observed at room temperature. The possible up-conversion mechanisms are discussed and estimated. This novel oxychloride bismuth-germanium glass with low maximum phonon energy (˜730 cm -1) can be used as potential host material for up-conversion lasers.

Sun, Hongtao; Yu, Chunlei; Zhang, Liyan; Duan, Zhongchao; He, Dongbin; Zhang, Junjie; Hu, Lili; Jiang, Zhonghong

2005-06-01

290

Intense upconversion luminescence in ytterbium-sensitized thulium-doped oxychloride germanate glass  

NASA Astrophysics Data System (ADS)

Structural and upconversion fluorescence properties in ytterbium-sensitized thulium-doped oxychloride germanate glass have been studied. The structure of oxychloride germanate glass was investigated by peak-deconvolution of Raman spectrum, and the structural information was obtained from the peak wavenumbers. The Raman spectrum investigation indicates that PbCl 2 plays an important role in the formation of glass network, and has an important influence on the upconversion luminescence. Intense blue and weak red emissions centered at 477 and 650 nm, corresponding to the transitions 1G 4? 3H 6 and 1G 4? 3H 4, respectively, were observed at room temperature. The possible upconversion mechanisms are discussed and estimated. Intense upconversion luminescence indicates that oxychloride germanate glass can be used as potential host material for upconversion lasers.

Sun, Hongtao; Zhanga, Liyan; Zhang, Junjie; Wen, Lei; Yu, Chunlei; Duan, Zhongchao; Dai, Shixun; Hu, Lili; Jiang, Zhonghong

2005-04-01

291

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

SciTech Connect

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

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

2005-01-31

292

Devitrification of Nd 3+ -doped glasses in the akermanite-gehlenite system  

Microsoft Academic Search

The devitrification of glasses in the akermanite-gehlenite system [(C2Al2?2yMgySi1+yO7 (0?y?1)] doped with Nd3+ (2% mol) has been studied. DTA was used to determine the kinetics of the process. The Avrami law ?=1-exp(?kt\\u000a n) withn=1 was found to hold for doped gehlenite. For pure gehlenite, parametern was determined to be 1.5. The activation energy of the devitrification process is independent of

A. Ma?ecki; A. M. Lejus; B. Viana; D. Vivien; R. Collongues

1995-01-01

293

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

294

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

E-print Network

in nanoparticles, clusters, or more complex structures, giving rise to a kind of self- assembled metamaterial.1. reported that initially isotropic silver- doped glasses become birefringent under strong laser illumination

Marrucci, Lorenzo

295

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

E-print Network

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

Sokolov, V O; Dianov, E M

2011-01-01

296

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

PubMed

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

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

2010-01-01

297

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

NASA Astrophysics Data System (ADS)

Optically active glass-ceramics (GC) with the low-phonon phases of fluorides, doped with Er3+ was studied. Glass based on SiO2-Al2O3-Na2F2-Na2O-GdF3-BaO system was obtained. Dopant were introduced to the glass in an amount of 0.01 mol Er2O3 per 1 mol of glass. DTA/DSC study shows multi-stage crystallization. XRD identification of obtained phases did not confirm the presence of pure GdF3 phase. Instead of that ceramization process led to formation of NaGdF4 and BaGdF5. The structural changes were studied using FT-IR spectroscopic method. The study of luminescence of the samples confirmed that optical properties of the obtained GC depend on crystallizing phases during ceramization. Time resolved spectroscopy of Er-doped glass showed the 3 and 8 times increase of lifetime of emission from 4S3/2 and 4F9/2 states, respectively. It confirms the erbium ions have ability to locate in the low phonon gadolinium-based crystallites. The results give possibility to obtain a new material for optoelectronic application.

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

2015-01-01

298

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

2010-09-15

299

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

NASA Astrophysics Data System (ADS)

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

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

2012-04-01

300

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

PubMed

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

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

2015-01-01

301

Evidence of coordinate field index influence on upconversion properties in Er3+ doped tellurite glasses.  

PubMed

Tellurite glasses doping the same concentration of Er3+ were prepared by conventional melting procedure, and their upconversion luminescences were measured. Two green emission bands at 521 nm and 550 nm and one red emission band at 657 nm were observed. This paper reported on the deduction of coordinate field index, which was proposed by deducing from Pauling's rules on the basis of Zachaiasen's random network theory, it was defined to the qualitative index that stand for the deviation of a given truly coordinate polyhedron from the hypothetical one. It can be used to rationalize the remarkable and regularity variation in the upconversion intensity in our prepared tellurite glasses. PMID:16794871

Su, Fangning; Deng, Zaide

2006-07-01

302

Tm-doped silicate glass fibre lasers: the foundation technology for high-power mid-infrared light generation  

NASA Astrophysics Data System (ADS)

The Tm-doped silicate glass fibre laser that operates in the 2 micron region of the spectrum is fast becoming a mature technology with output powers already exceeding 1 kW. In this paper, I will review a number of current and future experiments that involve lasers pumped with the output from Tm-doped silicate glass fibre lasers including linear systems e.g., the optical excitation of rare earth ions and nonlinear systems e.g., Raman fibre lasers.

Jackson, S. D.

2011-02-01

303

On the analogy between photoluminescence and carrier-type reversal in Bi- and Pb-doped glasses.  

PubMed

Reaction order in Bi-doped oxide glasses depends on the optical basicity of the glass host. Red and NIR photoluminescence (PL) bands result from Bi(2+) and Bin clusters, respectively. Very similar centers are present in Bi- and Pb-doped oxide and chalcogenide glasses. Bi-implanted and Bi melt-doped chalcogenide glasses display new PL bands, indicating that new Bi centers are formed. Bi-related PL bands have been observed in glasses with very similar compositions to those in which carrier-type reversal has been observed, indicating that these phenomena are related to the same Bi centers, which we suggest are interstitial Bi(2+) and Bi clusters. PMID:23571900

Hughes, Mark A; Gwilliam, Russell M; Homewood, Kevin; Gholipour, Behrad; Hewak, Daniel W; Lee, Tae-Hoon; Elliott, Stephen R; Suzuki, Takenobu; Ohishi, Yasutake; Kohoutek, Tomas; Curry, Richard J

2013-04-01

304

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

PubMed

Chalcogenide glasses doped with silver have many applications including their use as a novel radiation sensor. In this paper, we undertake the first atomistic simulation of radiation damage and healing in silver-doped Germanium-selenide glass. We jointly employ empirical potentials and ab initio methods to create and characterize new structural models and to show that they are in accord with many experimental observations. Next, we simulate a thermal spike and track the evolution of the radiation damage and its eventual healing by application of a simulated annealing process. The silver network is strongly affected by the rearrangements, and its connectivity (and thus contribution to the electrical conductivity) change rapidly in time. The electronic structure of the material after annealing is essentially identical to that of the initial structure. PMID:25426005

Prasai, Kiran; Drabold, David A

2014-01-01

305

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

306

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

PubMed Central

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

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

2013-01-01

307

Effects of chloride introduction on up-conversion luminescence in Tm3+ -doped tellurite glasses.  

PubMed

Blue up-conversion luminescence properties in Tm3+ -doped lead chloride tellurite glasses have been studied under 980 nm excitation. The intense blue and relatively weak red emissions centered at 476 and 649 nm corresponding to the transitions 1G4 --> 3H6 and 1G4 --> 3H4 of Tm3+, respectively, are simultaneously observed at room temperature. The effect of PbCl2 on up-conversion intensity is observed and discussed, and possible up-conversion mechanisms are evaluated. The intense blue up-conversion luminescence of Tm3+ -doped lead chloride tellurite glasses may be a potentially useful material for developing up-conversion optical devices. PMID:15477139

Xu, Shiqing; Yang, Zhongmin; Wang, Guonian; Zhang, Junjie; Dai, Shixun; Hu, Lili; Jiang, Zhonghong

2004-11-01

308

Upconversion luminescence of Yb 3+/Tb 3+ co-doped tellurite glasses  

NASA Astrophysics Data System (ADS)

In the article the upconversion luminescence ofTeO2- GeO2 - PbO - PbF2- BaO - Nb2O5 - LaF3 glass system co-doped withYb 3+ /Tb 3+ under 976 nm laser diode excitation was investigated. The influence of Tb2O3concentration on the luminescent properties was determined. Measured strong luminescence at492, 547, 588, 622 nm correspond to 5D4?7FJ (J=6, 4, 3) transitions. Energy transfer (ET) mechanism involved in observed emission was discussed. The highest upconversion emission intensity was obtained in the tellurite glass co-doped with 0.5 Yb2O3/0.5 Tb2O3 (mol%).

Kochanowicz, Marcin; Zmojda, Jacek; Dorosz, Dominik; Miluski, Piotr; Dorosz, Jan

2014-05-01

309

Single-mode waveguides generated in Nd3+-doped silicate glass by nickel ion irradiation  

NASA Astrophysics Data System (ADS)

Single mode waveguide in Nd3+-doped silicate glass substrate was fabricated by ion implantation technique. Nd3+-doped silicate glass is irradiated with 3 MeV Ni ions at a fluence of 5 × 1014 ions/cm2. The prism-coupling method is used to measure the effective refractive indices of the waveguide dark modes. Only one mode is found, in which its effective index (neff = 1.5207) is higher than the substrate index (nsub = 1.5202). The refractive index distribution of the waveguide was reconstructed; and the near-field intensity distribution is in a good agreement with simulated modal profiles. Propagation losses of the light in the waveguides were measured by the back-reflection method. It is found that after annealing the propagation loss of waveguide is effectively reduced.

Fu, Gang; Li, Shiling; Qin, Xifeng; Zhang, Xiuquan

2013-11-01

310

Effects of chloride introduction on up-conversion luminescence in Tm 3+-doped tellurite glasses  

NASA Astrophysics Data System (ADS)

Blue up-conversion luminescence properties in Tm 3+-doped lead chloride tellurite glasses have been studied under 980 nm excitation. The intense blue and relatively weak red emissions centered at 476 and 649 nm corresponding to the transitions 1G4? 3H6 and 1G4? 3H4 of Tm 3+, respectively, are simultaneously observed at room temperature. The effect of PbCl 2 on up-conversion intensity is observed and discussed, and possible up-conversion mechanisms are evaluated. The intense blue up-conversion luminescence of Tm 3+-doped lead chloride tellurite glasses may be a potentially useful material for developing up-conversion optical devices.

Xu, Shiqing; Yang, Zhongmin; Wang, Guonian; Zhang, Junjie; Dai, Shixun; Hu, Lili; Jiang, Zhonghong

2004-11-01

311

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

PubMed

This work focuses on the structural changes of barium chloride (BaCl2) nanoparticles in fluorochlorozirconate-based glass ceramics when doped with two different luminescent activators, in this case rare-earth (RE) ions, and thermally processed using a differential scanning calorimeter. In a first step, only europium in its divalent and trivalent oxidation states, Eu(2+) and Eu(3+), is investigated, which shows no significant influence on the crystallization of hexagonal phase BaCl2. However, higher amounts of Eu(2+) increase the activation energy of the phase transition to an orthorhombic crystal structure. In a second step, nucleation and nanocrystal growth are influenced by changing the structural environment of the glasses by co-doping with Eu(2+) and trivalent Gd(3+), Nd(3+), Yb(3+), or Tb(3+), due to the different atomic radii and electro-negativity of the co-dopants. PMID:23745010

Paßlick, C; Johnson, J A; Schweizer, S

2013-07-01

312

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

SciTech Connect

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

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

2014-02-14

313

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

NASA Astrophysics Data System (ADS)

Tellurite glasses doped Er3+ ions and containing Silver nanoparticles (Ag NPs) are prepared using melt quenching technique. The nucleation and growth of Ag NPs were controlled by a thermal annealing process. The X-ray diffraction pattern shows no sharp peak indicating an amorphous nature of the glasses. The presence of Ag NPs is confirmed from transmission electron microscopy micrograph. Absorption spectra show typical surface plasmon resonance (SPR) band of Ag NPs within the 510-550 nm range in addition to the distinctive absorption peaks of Er3+ ions. The Judd-Ofelt (J-O) intensity parameters, oscillator strengths, spontaneous transition probabilities, branching ratios, and radiative lifetimes were successfully calculated based on the experimental absorption spectrum and the J-O theory. It was found that the presence of silver NPs nucleated and grown during the heat annealing process improves both of the photoluminescence (PL) intensity and the PL lifetime relative to the 4I13/2 ? 4I15/2 transition. Optimum PL enhancement was obtained after 10 h of heat-treatment. Such enhancements are mainly attributed to the strong local electric field induced by SPR of silver NPs and also to energy transfer from the surface of silver NPs to Er3+ ions, whereas the quenching is ascribed to the energy transfer from Er3+ ions to silver NPs. Using the Mc Cumber method, absorption cross-section, calculated emission cross-section, and gain cross-section for the 4I13/2 ? 4I15/2 transition were determined and compared for the doped and co-doped glasses. The present results indicate that the glass heat-treated for 10 h has good prospect as a gain medium applied for 1.53 ?m band broad and high-gain erbium-doped fiber amplifiers.

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

2014-09-01

314

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

NASA Astrophysics Data System (ADS)

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

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

2014-02-01

315

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

NASA Technical Reports Server (NTRS)

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

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

1991-01-01

316

DBR and DFB lasers in neodymium- and ytterbium-doped photothermorefractive glasses.  

PubMed

The first demonstration, to the best of our knowledge, of distributed Bragg reflector (DBR) and monolithic distributed feedback (DFB) lasers in photothermorefractive glass doped with rare-earth ions is reported. The lasers were produced by incorporation of the volume Bragg gratings into the laser gain elements. A monolithic single-frequency solid-state laser with a linewidth of 250 kHz and output power of 150 mW at 1066 nm is demonstrated. PMID:24686699

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

2014-04-01

317

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

318

Characterization of Undoped and Cu-Doped ZnO Thin Films Deposited on Glass Substrates by Spray Pyrolysis  

NASA Astrophysics Data System (ADS)

Undoped and copper doped zinc oxide (ZnO) thin films have been prepared on glass substrates by spray pyrolysis technique. The films were doped with copper using the direct method by addition of a copper salt (CuCl2) in the spray solution of ZnO. Variation of structural, electrical, optical and thermoluminescence (TL) properties with doping concentrations is investigated in detail.

Metin, Bedir; Mustafa, Öztas; A. Necmeddin, Yazici; E. Vural, Kafadar

2006-04-01

319

CRYSTALLINE THORIUM BORATE  

Microsoft Academic Search

Crystalline thorium borate (ThBâOâ) was synthesized by the ; reaction of thoria with boric oxide at elevated temperatures; crystals suitable ; for single-crystal x-ray studies were grown in molten boric oxide at 1300 deg C. ; Crystallographic, chemical, and some physical properties of thorium borate ; crystals are presented as well as the results of a preliminary phase study of

Y. Baskin; Y. Harada; J. H. Handwerk

1961-01-01

320

The research of properties of Eu3+-doped cadmium aluminium silicate glass  

NASA Astrophysics Data System (ADS)

We have prepared (40SiO2-14Al2O3-(40-x) CdO-2Li2O-2K2O-2Na2O -x Eu2O3) cadmium aluminium silicate glasses doped with europium by high temperature solid-state reaction method. The absorption spectra, excitation spectra, emission spectra are obtained. With the increase of Eu2O3, the absorption peaks are founded increasing to the best doped concentration and then reducing, which is nonlinear relationship. The charge-transfer band is moved to 320 nm due to the addition of Cd2+. We can see that the ratio of peak in 591 nm and 615 nm is 0.6-0.75 in general, and is unrelated to doped concentration. By changing concentration of Eu3+.We can adjust and mix different intensity of light according to the demand.

Chen, Yue-e.; Hou, Lan-tian; Song, Zhao-yuan

2008-11-01

321

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

NASA Astrophysics Data System (ADS)

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

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

2014-09-01

322

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

SciTech Connect

Rare earth (RE) doped materials have been widely exploited as the intriguing electronic configuration of RE ions offers diverse functionalities from optics to magnetism. However, the coupling of magnetism with photoluminescence (PL) in such materials has been rarely reported in spite of its fundamental significance. In the present paper, the effect of high pulsed magnetic field on the photoluminescence intensity of Eu{sup 3+}-doped nano-glass-ceramics has been investigated. In our experiment, Eu-doped oxyfluoride glass and glass ceramic were prepared by the conventional melt-quenching process and controlled heat treatment. The results demonstrate that the integrated PL intensity of Eu{sup 3+} decreases with the enhancement of magnetic field, which can be interpreted in terms of cooperation effect of Zeeman splitting and magnetic field induced change in site symmetry. Furthermore, as a result of Zeeman splitting, both blue and red shift in the emission peaks of Eu{sup 3+} can be observed, and this effect becomes more prominent with the increase of magnetic field. Possible mechanisms associated with the observed magneto-optical behaviors are suggested. The results of the present paper may open a new gate for modulation of luminescence by magnetic field and remote optical detection of magnetic field.

Jiang, Wei; Chen, Weibo; Chen, Ping; Xu, Beibei; Zheng, Shuhong; Guo, Qiangbing; Liu, Xiaofeng, E-mail: xfliu@zju.edu.cn, E-mail: qjr@zju.edu.cn [State Key Laboratory of Silicon Materials, Department of Materials Science and Engineering, Zhejiang University, Hangzhou, Zhejiang 310027 (China); Zhang, Junpei; Han, Junbo [Wuhan National High Magnetic field Center, Huazhong University of Science and Technology, Wuhan, Hubei 430074 (China); Qiu, Jianrong, E-mail: xfliu@zju.edu.cn, E-mail: qjr@zju.edu.cn [State Key Laboratory of Silicon Materials, Department of Materials Science and Engineering, Zhejiang University, Hangzhou, Zhejiang 310027 (China); State Key Laboratory of Luminescent Materials and Devices, South China University of Technology, Guangzhou, Guangdong 510640 (China)

2014-09-28

323

Optical and luminescent properties of Sm3+ doped tellurite glasses  

NASA Astrophysics Data System (ADS)

Glasses with chemical composition of (62-x) TeO2 + 25 ZnO + 8 K2O + 5 CaO + x Sm2O3 (TZKCSmx; x = 0.1, 0.5, 1.0, 1.5 mol%) were prepared by melt quenching technique. The absorption spectrum was recorded in the UV-visible and NIR regions. The oscillator strengths of absorption bands were obtained by measuring the area under the bands. Judd-Ofelt analysis has been carried out to estimate the host dependent J-O intensity ?? (? = 2, 4, 6) parameters by least squares fitting approach. Photoluminescence spectra recorded in the visible region revealed intense green, orange and red emission bands in all the glasses, corresponding to the 4G?6H, 4G?6H and 4G?6H transitions respectively. From the emission spectra and J-O intensity parameters, various radiative parameters were calculated from the excited 4G to the lower lying 6 state decrease with the increase of the Sm3+ ions concentration. The energy transfer mechanism that leads to the quenching of 4G state lifetime has been discussed. Inokuti-Hirayama (I-H) model was used to evaluate various energy transfer parameters, which are the qualitative indicators for the interaction among Sm3+ ions.

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

2013-03-01

324

Fabrication of uniformly dispersed nanoparticle-doped chalcogenide glass  

NASA Astrophysics Data System (ADS)

The dispersion of metallic nanoparticles within a chalcogenide glass matrix has the potential for many important applications in active and passive optical materials. However, the challenge of particle agglomeration, which can occur during traditional thin film processing, leads to materials with poor performance. Here, we report on the preparation of a uniformly dispersed Ag-nanoparticle (Ag NP)/chalcogenide glass heterogeneous material prepared through a combined laser- and solution-based process. Laser ablation of bulk silver is performed directly within an arsenic sulfide/propylamine solution resulting in the formation of Ag NPs in solution with an average particle size of less than 15 nm as determined by dynamic light scattering. The prepared solutions are fabricated into thin films using standard coating processes and are then analyzed using energy-dispersive X-ray spectroscopy and transmission electron microscopy to investigate the particle shape and size distribution. By calculating the nearest neighbor index and standard normal deviate of the nanoparticle locations inside the films, we verify that a uniformly dispersed distribution is achieved through this process.

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

2014-12-01

325

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

326

Intense red upconversion emission of Yb/Tm/Ho triply-doped tellurite glasses.  

PubMed

By conventional melting and quenching methods, 3Yb2O3-0.2Tm2O3-xHo2O3 (wt%, x=0.2~1.2) was doped into an easily fiberized tellurite glass with composition of 78TeO2-10ZnO-12Na2O (mol%) to form YTH-TZN78 glasses. Under 976 nm excitation, the direct sensitizing effect of Yb ions (Yb?Ho) and indirect sensitizing and self-depopulating effects of Tm ions (Yb?Tm?Ho) were found to present intense red upconversion emission at 657 nm (Red, Ho:5F5?5I8) and were responsible for the absence of the usually observed 484 nm emission (Blue, Tm:1G4?3H36). Regardless of the dopant concentration of Ho ions, the intensity of the red emission at 657 nm (Red, Ho:5F5?5I8) is about three times stronger than that of the green one at 543 nm (Green, Ho:5S2?5I8). For this certain red emission at 657 nm, 0.4 wt% Ho2O3-doped YTH-TZN78 glass was found to present the highest emission intensity and is therefore determined as a promising active tellurite glass for red fiber laser development. PMID:22614614

Zhan, Huan; Zhou, Zhiguang; He, Jianli; Lin, Aoxiang

2012-05-20

327

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

NASA Astrophysics Data System (ADS)

Structure and thermal properties of xTiO2·(90 - x) (60P2O5-40Fe2O3)?10CaF2 (x = 0, 5, 10, 15, 20 and 25 mol%) glasses are investigated in detail by Fourier Transform Infrared Spectrum (FTIR) and Differential Thermal Analysis (DTA), respectively. It is found that incorporation of TiO2 increase the density and glass transition temperature of iron phosphate system glass. The increment of doped-TiO2 can also strengthen phosphate network chains due to increasing O/P ratios and more orthophosphate (Q0) units formed in the glass structure at expense of pyrophosphate (Q1) units and metaphosphate (Q2) groups. Moreover, the structure of iron phosphate glass with TiO2 content contain distorted octahedral [TiO6] linked to phosphate unit through Psbnd Osbnd Ti bonds, thus enhanced structure cohesion and increased density obtained. The knowledge provides an improved understanding of the role of TiO2 in the structure of iron phosphate glasses.

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

2015-02-01

328

Tm3+-doped ion-exchanged aluminum germanate glass waveguide for S-band amplification  

NASA Astrophysics Data System (ADS)

K+-Na+ ion-exchanged channel waveguide amplifiers have been fabricated in Tm3+-doped acid-resistant aluminum germanate glasses. The optical and relative gains of a 3.15-cm-long waveguide channel were achieved to be 4.05 and 2.29 dB at 1.482 ?m wavelength under 110 mW 793 nm laser excitation, respectively. After compensating the propagation loss, an internal gain of 1.50 dB and a remarkable gain coefficient of 0.48 dB/cm were obtained, which reveals a definite S-band signal amplification in the low phonon energy glass waveguide. As an expectation, UV-radiation-sensitive glass waveguide should promote the developments of gain-flatten S-band waveguide amplifiers, infrared UV-writing grating waveguide lasers, and compact multifunctional integrated optical devices.

Yang, D. L.; Pun, E. Y. B.; Lin, H.

2009-10-01

329

Intense 2.7 µm emission of Er3+-doped water-free fluorotellurite glasses.  

PubMed

By physical and chemical dehydration techniques, a group of Er3+-doped water-free fluorotellurite glasses with a composition of 60TeO2-30ZnF2-10NaF(TZNF60,mol%)+x Er2O3(wt%,x=0~1.5) were fabricated. Under 978 nm excitation, the 4I(11/2)?4I(13/2) emission of Er3+ ions in TZNF60-glass was investigated: ?(f) is of 1.07~1.93 ms and emission bandwidth is about 163 nm at 2.71 µm, which benefits from the absence of OH groups and the decreased phonon energy with the addition of fluorides. In contrast, 1.25Er-TZNF60 glass is proposed to be a promising material for mid-infrared fiber lasers at around 2.7 µm. PMID:23381273

Zhan, Huan; Zhou, Zhiguang; He, Jianli; Lin, Aoxiang

2012-08-15

330

Broadband amplification and upconversion luminescence properties of Er 3+/Yb 3+ co-doped fluorophosphate glass  

NASA Astrophysics Data System (ADS)

Broadband and upconversion properties were studied in Er 3+/Yb 3+ co-doped fluorophosphate glasses. Large ?6 and Sed/( Sed+ Smd) values and the flat gain profile over 1530-1585 nm indicate the good broadband properties of the glass system. And a premise of using ?6 as a parameter to estimate the broadband properties of the glasses is proposed for the first time to our knowledge. Results showed that fluorescence intensity, upconversion luminescence intensity, the intensity ratio of red/green light (656 nm/545 nm) are closely related to the Yb 3+:Er 3+ ratio and Er 3+ concentration, and the corresponding calculated lifetime of 4F 9/2 and 4S 3/2 states for red and green upconversion samples proves this conclusion. The upconversion mechanism is also discussed.

Zhang, Liyan; Sun, Hongtao; Xu, Shiqing; Li, Kefeng; Hu, Lili

2005-08-01

331

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

NASA Astrophysics Data System (ADS)

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

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

2004-07-01

332

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

NASA Astrophysics Data System (ADS)

The Dy3+ doped Zinc borophosphate glasses with the chemical composition (79-x)B2O3+xP2O5+10Li2O+10ZnO+1Dy2O3 (where x=0, 10, 20, 30 and 50 in wt%) have been prepared by melt quenching technique. The prepared glass samples were characterized through optical absorption, emission and decay measurements. The bonding parameters, optical band gap and Urbach's energy values were calculated from the optical absorption spectra to explore the bonding nature of the Dy-O metal ligand and electronic band structure of the studied glasses. Judd-Ofelt (JO) intensity parameters were calculated from the absorption spectra by using the JO theory and it gives information about symmetry of the ligand environment around the Dy3+ ion site. The Y/B intensity ratio and radiative properties were obtained from the emission spectra and the results were compared with the reported literature. The x, y chromaticity color coordinates of the studied glasses were analyzed using a CIE 1931 color chromaticity diagram and found that the x, y coordinates lie in the white light region. The decay curve measurements of the prepared glasses exhibit non-exponential behavior and are well fitted to Inokuti-Hirayama (IH) model to understand the energy transfer mechanism between Dy3+ ions. The Q, R0 and CDA values of the prepared Dy3+ doped glasses were obtained from the IH model and the results were discussed and compared with the reported literature.

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

2015-01-01

333

Analysis of structure origin and luminescence properties of Yb(3+)-Er(3+) co-doped fluorophosphate glass.  

PubMed

The near infrared luminescence properties of Yb(3+)-Er(3+) co-doped fluorophosphate glasses have been investigated. The various effects on structure and 1.53 ?m emission were analyzed as a function of Yb(3+) concentration. The energy transfer mechanism was proposed. High measured lifetime (10.75 ms), large effective full widths at half maximum (73.71 nm) and large gain per unit length (62.8 × 10(-)(24)cm(2)s) have been achieved in prepared glass. The present glass co-doped with 6mol% YbF3 and 2 mol% ErF3 showed magnificent luminescence properties for telecommunication application. PMID:24747331

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

2014-08-14

334

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

PubMed Central

Eu2+-doped fluorochlorozirconate (FCZ) glasses and glass ceramics, which are being developed for medical and photovoltaic applications, have been analysed by Mössbauer spectroscopy. The oxidation state and chemical environment of the europium ions, which are important for the performance of these materials, were investigated. Routes for maximizing the divalent europium content were investigated. By using EuCl2 instead of EuF2 in the starting material a fraction of about 90% of the europium was maintained in the Eu2+ state as opposed to about 70% when using EuF2. The glass ceramics produced by subsequent thermal processing contain BaCl2 nanocrystals in which Eu2+ is incorporated, as shown by the narrower linewidth in the Mössbauer spectrum. Debye temperatures of 147 K and 186 K for Eu2+ and Eu3+, respectively, were determined from temperature dependent Mössbauer measurements. The f-factors were used to obtain the Eu2+/Eu3+ ratio from the area ratio of the corresponding absorption lines. PMID:23603535

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

2013-01-01

335

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

NASA Astrophysics Data System (ADS)

Eu2+-doped fluorochlorozirconate (FCZ) glasses and glass ceramics, which are being developed for medical and photovoltaic applications, have been analysed by Mössbauer spectroscopy. The oxidation state and chemical environment of the europium ions, which are important for the performance of these materials, were investigated. Routes for maximizing the divalent europium content were also investigated. By using EuCl2 instead of EuF2 in the starting material a fraction of about 90% of the europium was maintained in the Eu2+ state as opposed to about 70% when using EuF2. The glass ceramics produced by subsequent thermal processing contain BaCl2 nanocrystals in which Eu2+ is incorporated, as shown by the narrower linewidth in the Mössbauer spectrum. Debye temperatures of 147 K and 186 K for Eu2+ and Eu3+, respectively, were determined from temperature dependent Mössbauer measurements. The f-factors were used to obtain the Eu2+/Eu3+ ratio from the area ratio of the corresponding absorption lines.

Pfau, C.; Paßlick, C.; Gray, S. K.; Johnson, J. A.; Johnson, C. E.; Schweizer, S.

2013-05-01

336

Spectroscopic study of Er:Sm doped barium fluorotellurite glass.  

PubMed

In this paper, we report the physical and spectroscopic properties of Er(3+), Sm(3+) and Er(3+):Sm(3+) ions codoped barium fluorotellurite (BFT) glasses. Different Stokes and anti-Stokes emissions were observed under 532 nm and 976 nm laser excitations. Energy transfer from Er(3+) ion to Sm(3+) ion was confirmed on the basis of luminescence intensity variation and decay curve analysis in both the cases. Under green (532 nm) excitation emission intensity of Sm(3+) ion bands improves whereas on NIR (976 nm) excitation new emission bands of Sm(3+) ions were observed in Er:Sm codoped samples. Ion interactions and the different energy transfer parameters were also calculated. PMID:20510646

Bahadur, A; Dwivedi, Y; Rai, S B

2010-09-15

337

Optical and luminescent properties of Sm³+ doped tellurite glasses.  

PubMed

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

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

2013-03-01

338

Effect of SiO2 on the thermal stability and spectroscopic properties of Er3+-doped tellurite glasses  

NASA Astrophysics Data System (ADS)

Er3+-doped tellurite glass (TeO2-ZnO-Na2O) prepared using the conventional melt-quenching method is modified by introducing the SiO2, and its effects on the thermal stability of glass host and the 1.53 ?m band spectroscopic properties of Er3+ are investigated by measuring the absorption spectra, 1.53 ?m band fluorescence spectra, Raman spectra and differential scanning calorimeter (DSC) curves. It is found that for Er3+-doped tellurite glass, besides improving its thermal stability, introducing SiO2 is helpful for the further improvement of the fluorescence full width at half maximum (FWHM) and bandwidth quality factor. The results indicate that the prepared Er3+-doped tellurite glass containing an appropriate amount of SiO2 has good prospect as a candidate of gain medium applied for 1.53 ?m broadband amplifier.

Zheng, Shi-chao; Zhou, Ya-xun

2014-05-01

339

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

NASA Astrophysics Data System (ADS)

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

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

2014-03-01

340

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

341

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

PubMed

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

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

2014-01-28

342

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

SciTech Connect

In this work, Judd-Ofelt analysis is applied to rare-earth (RE = Nd{sup 3+}) doped cadmium bismuth silicate (20CdO?xSiO{sub 2}?(79.5?x)Bi{sub 2}O{sub 3}?0.5Nd{sub 2}O{sub 3} (CSBN)) glasses in order to evaluate their potential as well as both glass laser systems and optical materials. The phenomenological Judd-Ofelt parameters (?{sub 2}, ?{sub 4}, ?{sub 6}) are determined for RE ions with their quality factors and compared with the equivalent parameters for several other hosts. The calculated value of stimulated emission cross-section for {sup 4}F{sub 3/2}?{sup 4}I{sub 11/2} has high and varies 14.72×10{sup ?20} to 9.66×10{sup ?20} cm{sup 2} with Bi{sub 2}O{sub 3} content in the host glass. The results point out that the glass system is good candidate for the development of photonics devices which are operating near infrared spectral range. Further, the FTIR results reveal that the glasses have BiO{sub 6}, SiO{sub 4} and non-bridging oxygen as local structure.

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

2014-04-24

343

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

PubMed

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

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

2009-02-01

344

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

NASA Astrophysics Data System (ADS)

In this work, Judd-Ofelt analysis is applied to rare-earth (RE = Nd3+) doped cadmium bismuth silicate (20CdO?xSiO2?(79.5-x)Bi2O3?0.5Nd2O3 (CSBN)) glasses in order to evaluate their potential as well as both glass laser systems and optical materials. The phenomenological Judd-Ofelt parameters (?2, ?4, ?6) are determined for RE ions with their quality factors and compared with the equivalent parameters for several other hosts. The calculated value of stimulated emission cross-section for 4F3/2?4I11/2 has high and varies 14.72×10-20 to 9.66×10-20 cm2 with Bi2O3 content in the host glass. The results point out that the glass system is good candidate for the development of photonics devices which are operating near infrared spectral range. Further, the FTIR results reveal that the glasses have BiO6, SiO4 and non-bridging oxygen as local structure.

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

2014-04-01

345

Spectroscopic studies of copper doped alkaline earth lead zinc phosphate glasses  

NASA Astrophysics Data System (ADS)

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

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

2014-02-01

346

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

NASA Astrophysics Data System (ADS)

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

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

2013-05-01

347

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

NASA Astrophysics Data System (ADS)

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 Ce 3+ ions placed mainly in two different sites of the glass network. As Ag + ions are introduced into the cerium doped glass, they are reduced to elementary silver (Ag 0) which are favoured by the reaction Ce 3++Ag +?Ce 4++Ag 0. Then, the number of Ce 3+ ions decrease inversely with depth from the surface contrarily to Ce 4+ ions does, and elementary silver diffuses and aggregates to form nanoparticles. As a consequence of these changes, the OA spectra of exchanged samples increase substantially in the UV range and the luminescence decreases significantly. The high sensitivity of PL together with deconvolution analysis of spectra, however, allows us to detect changes in the excitation and emission spectra from the earlier stages of ion-exchange. This indicates that during the ion-exchange we deal with fast processes (much shorter than 1 min). In fact, transmission electron microscopy observations of samples from the glass exchanged for a short time as 1 min at 325°C show the presence of a scanty number of silver nanoparticles, which confirms this point. Furthermore, with increasing the length of time of ion-exchange, PL spectra exhibit a progressive red shift indicative in part of a covalence increment in the oxygen-cerium coordinated bonding. We observe no luminescence from Ag + ions and other silver molecular species in contrast with other preliminary PL studies on silver ion-exchange in soda-lime-silicate glasses free of cerium. The effect is discussed on the basis of a supplementary increase in the number of Ce 4+ ions mainly due to the reaction Ce 3++Ag +?Ce 4++Ag 0, which prevents efficiently the luminescence of the silver centers.

Paje, S. E.; García, M. A.; Villegas, M. A.; Llopis, J.

2001-09-01

348

Spectroscopic study of ZnO doped CeO 2-PbO-B 2O 3 glasses  

NASA Astrophysics Data System (ADS)

Glass samples of compositions xZnO- xCeO 2-(30- x)PbO-(70- x)B 2O 3 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 BO 3 are transformed into BO 4. It has been observed in our previous work that band gap decreases from 2.89 to 2.30 eV for CeO 2-PbO-B 2O 3 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 CeO 2-PbO-B 2O 3 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/cm 3). Transmittance shows that ZnO in glass samples acts as a reducing agent thathelps to convert Ce 4+?Ce 3+ ions.

Pal Singh, Gurinder; Singh, D. P.

2011-09-01

349

Broadband near-infrared emission from Cr 4+-doped transparent glass-ceramics based on lithium silicate  

NASA Astrophysics Data System (ADS)

Cr 4+-doped transparent glass-ceramics containing Li 4SiO 4 nanocrystals were prepared by heat-treatment on as-made glasses. It was confirmed from absorption spectra that the energy levels of Cr 4+-doped the glass-ceramics is close to the cross point 1E and 3T states. The broadband infrared emission centered at 1230 nm with the full width at half maximum (FWHM) of more than 240 nm was observed by exciting the glass-ceramics with excitation of an 808 nm laser diode. The lifetime was about 230 ?s at room temperature. The observed infrared emission could be attributed to Cr 4+ ions at low-field sites in Li 4SiO 4 glass-ceramics.

Deng, Degang; Xu, Shiqing; Ju, Haidong; Zhao, Shilong; Wang, Huanping; Li, Chenxia

2010-02-01

350

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

NASA Astrophysics Data System (ADS)

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

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

2012-08-01

351

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

NASA Astrophysics Data System (ADS)

In this study, ZnTe (II-VI) semiconductor and Eu+3-ion co-doped borosilicate glass has been prepared in the SiO2-K2O-CaO-BaO-B2O3 glass system followed by controlled heat-treatment to produce glass nanocomposites. Glass transition temperature and crystallization peak temperature have been evaluated using DSC analysis. Dilatometric studies were carried out to evaluate thermal expansion co-efficient, glass transition temperature, and dilatometric softening temperature and found to be 10.7 × 10-6/K, 580° C and 628° C, respectively. TEM micrographs demonstrate formation of nano sized crystallites of less than 50 nm. The ZnTe crystal formation also established through selected area electron diffraction (SAED) analysis and high resolution images obtained through TEM studies. With increasing heat treatment time, optical transmission cut-off wavelength (?cut-off) shifted towards higher wavelength. Excitation spectra were recorded by monitoring emission at 613 nm corresponding to the 5D0 ? 7F2 transition. An intense 394 nm excitation band corresponding to the 7F0 ? 5L6 transition was observed. Emission spectra were then recorded by exciting the glass samples at 394 nm. When the glass is heat-treated for 30 min at 610° C, a 6-fold increase in the intensity of the red emission at 612 nm has been observed, which is attributed to the segregation of Eu3+ ions into the low phonon energy ZnTe crystallites and as the size of the nanocrystals is smaller than the size of the exciton, quantum confinement effect is visible. Further increase in heat-treatment duration led to decrease in luminescence intensity due to the growth of larger size crystals. 5D1 ? 7F0 transition is visible only in the samples heat-treated for 30 min and 1 h, which is a characteristic of presence of Eu3+ ions in the low phonon energy ZnTe crystal sites. The micro hardness of the precursor glass and glass nanocomposites was evaluated; base glass shows hardness of 6.7 GPa and hardness of heat-treated glass nanocomposites has been found to decrease with increase in heat-treatment duration (5.5-5.3 GPa). However, mechanical properties are found to be suitable for device applications.

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

2014-10-01

352

Structural and optical properties of Tb-doped Na-Gd metaphosphate glasses and glass-ceramics  

NASA Astrophysics Data System (ADS)

The optical and structural properties of terbium doped sodium gadolinium phosphate glasses of three different compositions subjected to a crystallization process were studied and compared with those of the parent glassy samples. The structural characteristics of the glassy and crystallized phases were determined by Raman spectroscopy and the results showed a remarkable reduction in the full width at half maximum of the Raman peaks after crystallization. Radio-luminescence measurements revealed the emissions of both Gd3+ and Tb3+ ions. Their intensities strongly increased and their intensity ratio was modified by the crystallization. The luminescence temperature dependence investigated by radio-luminescence measurements in the temperature interval from 10 to 310 K became more complicated after crystallization. The role of free carrier trapping phenomena in the modification of the radio-luminescence efficiency was also studied by thermally stimulated luminescence.

Moretti, F.; Vedda, A.; Nikl, M.; Nitsch, K.

2009-04-01

353

Structural and optical properties of Tb-doped Na-Gd metaphosphate glasses and glass-ceramics.  

PubMed

The optical and structural properties of terbium doped sodium gadolinium phosphate glasses of three different compositions subjected to a crystallization process were studied and compared with those of the parent glassy samples. The structural characteristics of the glassy and crystallized phases were determined by Raman spectroscopy and the results showed a remarkable reduction in the full width at half maximum of the Raman peaks after crystallization. Radio-luminescence measurements revealed the emissions of both Gd(3+) and Tb(3+) ions. Their intensities strongly increased and their intensity ratio was modified by the crystallization. The luminescence temperature dependence investigated by radio-luminescence measurements in the temperature interval from 10 to 310 K became more complicated after crystallization. The role of free carrier trapping phenomena in the modification of the radio-luminescence efficiency was also studied by thermally stimulated luminescence. PMID:21825356

Moretti, F; Vedda, A; Nikl, M; Nitsch, K

2009-04-15

354

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

355

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

NASA Technical Reports Server (NTRS)

A study was made on two commercially available terbium-doped silicate glasses. There is an increased interest in silicate glasses doped with rare-earth ions for use in high-energy particle detection and radiographic applications. These glasses are of interest due to the fact that they can be formed into small fiber sensors; a property that can be used to increase the spatial resolution of a detection system. Following absorption of radiation, the terbium ions become excited and then emit photons via 4f-4f electronic transitions as they relax back to the ground state. The lifetime of these transitions is on the order of milliseconds. A longer decay component lasting on the order of minutes has also been observed. While radiative transitions in the 4f shell of rare-earth ions are generally well understood by the Judd-Olfelt theory, the pr'esence of a longer luminescence decay component is not. Experimental evidence that the long decay component is due, in part, to the thermal release of trapped charge carriers will be presented. In addition, a theoretical model describing the time evolution of the radiation-induced luminescence will be presented.

West, Michael S.; Winfree, William P.

1996-01-01

356

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

NASA Astrophysics Data System (ADS)

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

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

2015-01-01

357

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

SciTech Connect

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

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

2012-06-05

358

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

359

Sol-gel synthesis and in vitro bioactivity of copper and zinc-doped silicate bioactive glasses and glass-ceramics.  

PubMed

Metal doping of bioactive glasses based on ternary 60SiO2-36CaO-4P2O5 (58S) and quaternary 60SiO2-25CaO-11Na2O-4P2O5 (NaBG) mol% compositions synthesized using a sol-gel process was analyzed. In particular, the effect of incorporating 1, 5 and 10?mol% of CuO and ZnO (replacing equivalent quantities of CaO) on the texture, in vitro bioactivity, and cytocompatibility of these materials was evaluated. Our results showed that the addition of metal ions can modulate the textural property of the matrix and its crystal structure. Regarding the bioactivity, after soaking in simulated body fluid (SBF) undoped 58S and NaBG glasses developed an apatite surface layer that was reduced in the doped glasses depending on the type of metal and its concentration with Zn displaying the largest inhibitions. Both the ion release from samples and the ion adsorption from the medium depended on the type of matrix with 58S glasses showing the highest values. Pure NaBG glass was more cytocompatible to osteoblast-like cells (SaOS-2) than pure 58S glass as tested by 3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide (MTT) assay. The incorporation of metal ions decreased the cytocompatibility of the glasses depending on their concentration and on the glass matrix doped. Our results show that by changing the glass composition and by adding Cu or Zn, bioactive materials with different textures, bioactivity and cytocompatibility can be synthesized. PMID:25760730

Bejarano, Julian; Caviedes, Pablo; Palza, Humberto

2015-01-01

360

Luminescence properties of Sm(3+)-doped P(2)O(5)-PbO-Nb(2)O(5) glass under high pressure.  

PubMed

Samarium doped lead phosphate glass modified with niobium having a composition (in mol%) of 55P(2)O(5)+39.5PbO+5Nb(2)O(5)+0.5Sm(2)O(3) has been prepared by the conventional melt quenching technique. The emission spectra and the decay curves for the (4)G(5/2) level of Sm(3+) ions have been measured as a function of pressure up to 23.6 GPa at room temperature. A discontinuity in the observed shifts and crystal-field splittings as a function of pressure around 9-10 GPa suggests that a phase transition is taking place in the glass matrix. The [Formula: see text], (6)H(7/2) and (6)H(9/2) transitions are shifted towards the lower energy side with magnitudes of -7.1, -7.6 and -5.5 cm(-1) GPa(-1) up to 8.9 GPa (phase 1) and -5.6, -4.9 and -4.4 cm(-1) GPa(-1) beyond 10.3 GPa (phase 2), respectively. A much stronger increase in the splitting of the [Formula: see text] and [Formula: see text] Stark levels with pressure is observed in phase 1 than in phase 2. The lifetime of the (4)G(5/2) level decreases from 2.29 ms (0 GPa) to 0.64 ms (23.6 GPa) with pressure. The decay curves of the (4)G(5/2) level exhibit non-exponential behavior for all the pressures and were fitted by the generalized Yokota-Tanimoto model to probe the nature of the energy transfer process. The best fits with S = 6 indicate that the energy transfer between donor and acceptor is of dipole-dipole type. The crystal-field splitting experienced by the Sm(3+) ions in the title glass are found to be larger than those found in borate, K-Ba-Al phosphate and tellurite glasses. PMID:21817267

Praveena, R; Venkatramu, V; Babu, P; Jayasankar, C K; Tröster, Th; Sievers, W; Wortmann, G

2009-01-21

361

Nd3+-doped soft glass double-clad fibers with a hexagonal inner cladding  

NASA Astrophysics Data System (ADS)

The stack-and-draw technique was used to fabricate Nd3+-doped silicate and phosphate glass double-clad step-index fibers with a non-circular inner cladding. For the silicate fiber, a maximum output power of 7.7?W was obtained from a 94?cm fiber. An output power of 1.25?W was also realized with a short length fiber of 8?cm, confirming the application potential of this fiber in single frequency lasers and pulsed amplifiers where an efficient rare-earth-doped fiber with short length is desirable. For the phosphate fiber, a maximum output power of 2.78?W was obtained from a single-mode fiber with a core diameter of up to 35??m.

Wang, Longfei; He, Dongbing; Hu, Lili; Chen, Danping

2015-04-01

362

Optical properties and energy transfer processes in (Tm3+, Nd3+) doped tungstate fluorophosphate glass  

NASA Astrophysics Data System (ADS)

We investigate the linear optical properties and energy transfer processes in tungstate fluorophosphate glass doped with thulium (Tm3+) and neodymium (Nd3+) ions. The linear absorption spectra from 370 to 3000 nm were obtained. Transitions probabilities, radiative lifetimes, and transition branching ratios were determined using the Judd-Ofelt [Phys. Rev. 127, 750 (1962); J. Chem. Phys. 37, 511 (1962)] theory. Frequency up-conversion to the blue region and fluorescence in the infrared were observed upon pulsed excitation in the range of 630-700 nm. The excitation spectra of the luminescence were obtained to understand the origin of the signals. The temporal decay of the fluorescence was measured for different concentrations of the doping ions. Energy transfer rates among the Tm3+ and Nd3+ ions were also determined.

Branda~O, Marconi J. S.; de Araújo, Cid B.; Poirier, Gael; Messaddeq, Younes; Poulain, M.

2006-06-01

363

Photocatalytic antibacterial performance of Sn(4+)-doped TiO(2) thin films on glass substrate.  

PubMed

Pure anatase, nanosized and Sn(4+) ion doped titanium dioxide (TiO(2)) particulates (TiO(2)-Sn(4+)) were synthesized by hydrothermal process. TiO(2)-Sn(4+) was used to coat glass surfaces to investigate the photocatalytic antibacterial effect of Sn(4+) doping to TiO(2) against gram negative Escherichia coli (E. coli) and gram positive Staphylococcus aureus (S. aureus). Relationship between solid ratio of TiO(2)-Sn(4+) in coatings and antibacterial activity was reported. The particulates and the films were characterized using particle size analyzer, zeta potential analyzer, Brunauer-Emmett-Teller (BET), X-ray diffractometer (XRD), SEM, AAS and UV/VIS/NIR techniques. The results showed that TiO(2)-Sn(4+) is fully anatase crystalline form and easily dispersed in water. Increasing the solid ratio of TiO(2)-Sn(4+) from 10 to 50% in the coating solution increased antibacterial effect. PMID:18656312

Sayilkan, Funda; Asiltürk, Meltem; Kiraz, Nadir; Burunkaya, Esin; Arpaç, Ertu?rul; Sayilkan, Hikmet

2009-03-15

364

Optical transition and upconversion luminescence in Er 3+ doped and Er 3+-Yb 3+ co-doped fluorophosphate glasses  

NASA Astrophysics Data System (ADS)

Fluorophosphates glasses YF 3-BaF 2-Ba(PO 3) 2 doped with Er 3+ and Er 3+-Yb 3+ were prepared and the structures of the samples were briefly investigated. The experimental intensity parameters were calculated according to the Judd-Ofelt theory, from which the radiative transition probabilities, fluorescence branching ratios, and radiative lifetimes of Er 3+ were obtained. Bright green and red upconversion emissions was observed in Er 3+-Yb 3+ co-doped samples excited by 980 nm laser diode, and two-photons absorption processes were determined for the emissions by examining the dependence of the emission intensity on the excitation power. The concentration effects on the intensity and decay time of the upconversion emission revealed that growing Er 3+ concentration declined the probability of sequential energy transfer from Yb 3+ to Er 3+, and thus increasing the intensity ratio of the red emission to the green ones. The temperature effects on the intensity ratios of different emission bands showed that the maximum transducer sensitivity based on the fluorescence intensity ratio (FIR) was calculated to be 0.0015/°C at 6 °C.

Lai, Boyuan; Feng, Li; Wang, Jing; Su, Qiang

2010-07-01

365

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

NASA Astrophysics Data System (ADS)

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

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

2013-12-01

366

Hall effect in Zr-Ni and Zr-Cu metallic glasses doped with hydrogen  

NASA Astrophysics Data System (ADS)

We have studied the effect of hydrogen doping on the Hall resistivity of paramagnetic Zr76Ni24, Zr40Ni60, Zr70Cu30, and Zr60Cu40 metallic glasses. All the alloys have positive Hall coefficients except the Zr40Ni60. The hydrogen dopant increases the absolute value of the Hall coefficient irrespective of its sign, except in the case of (Zr70Cu30)1-xHx, where the Hall coefficient decreases for low hydrogen concentrations (x<0.04) and increases at higher ones, while staying positive all the time. The results are explained as being due to the enhanced s-d hybridization.

Kokanovi?, I.; Leonti?, B.; Lukatela, J.; Ivkov, J.

1990-12-01

367

Proton-implanted optical planar waveguides in Yb3+-doped silicate glasses  

NASA Astrophysics Data System (ADS)

We report on the characterization of planar waveguides in Yb3+-doped silicate glasses fabricated by double-energy proton implantation at a total dose of 3 × 1016 ions/cm2. The dark mode spectroscopy and near-field mode profile were evaluated by the prism coupling and end-face coupling methods, respectively. The results indicate that a refractive index enhanced region as well as an optical barrier has been created after the beam process. We propose the ion exchange mechanism between the proton and Na+ ions to illustrate the optical barrier and discuss its influence.

Liu, Chun-Xiao; Cheng, Shu; Guo, Hai-Tao; Li, Wei-Nan; Liu, Xiu-Hong; Wei, Wei; Peng, Bo

2012-10-01

368

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

PubMed

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

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

2014-05-15

369

Study of upconversion fluorescence property of novel Er3+/Yb3+ co-doped tellurite glasses.  

PubMed

Er3+/Yb3+ co-doped TeO2-B2O3-Nb2O5-ZnO (TBN) glasses were prepared. The absorption spectra and upconversion luminescence spectra of TBN glasses were measured and analyzed. The upconversion emission bands centered at 530, 546 and 658 nm were observed under the excitation at 975 nm, corresponding to the transitions of 2H11/2-->4I15/2, 4S3/2-->4I15/2 and 4F9/2-->4I15/2 respectively. The ratio of red emission to green emission increases with an increasing of Yb3+ ions concentration. According to the quadratic dependence on excitation power, the possible upconversion mechanisms and processes were discussed. PMID:16458052

Xu, Tie-Feng; Li, Guang-Po; Nie, Qiu-Hua; Shen, Xiang

2006-06-01

370

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

371

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.

2008-02-01

372

Ho3+ doped fluorophosphate glasses sensitized by Yb3+ for efficient 2 ?m laser applications  

NASA Astrophysics Data System (ADS)

In this paper, new Ho3+/Yb3+ co-doped fluorophosphate glasses with superior thermal stability against crystallization have been synthesized. Intense 2 ?m emissions have been observed when pumped by a conventional 980 nm laser diode. High infrared transmittance (82%) and low hydroxyl concentration (16.7 ppm) can be realized according to the analysis of infrared transmittance spectrum. Based on the measured absorption spectra, a thorough calculation of the Judd-Ofelt parameters and radiative properties has been carried out. The predicted spontaneous transition probability, emission cross section and gain coefficient of Ho3+:5I7?5I8 can reach to 74.11 s-1, 4.53×10-21 cm2, and 0.8 cm-1, respectively. Besides, the energy transfer coefficients from Yb3+ to Ho3+ have also been calculated and discussed. The results suggest the prepared glass is a good candidate for efficient 2 ?m laser.

Chen, Hongfei; Chen, Fangze; Wei, Tao; Liu, Qunhuo; Shen, Ruixu; Tian, Ying

2014-06-01

373

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

NASA Astrophysics Data System (ADS)

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

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

2011-09-01

374

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

SciTech Connect

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

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

2011-09-19

375

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

PubMed

In the work the new glass compositions in the GeO2-GaO-BaO system have been prepared and thermal, structural properties of in germanate glasses co-doped with Yb(3+)/Tb(3+)ions were studied. Glasses were obtained by conventional high-temperature melt-quenching technique. The study of the crystallization kinetics processes of glasses co-doped with 0.7Yb2O3:0.7Tb2O3 was performed with DSC measurements. The activation energies have been calculated using Freedman analysis and verified with the Flynn-Wall-Ozawa method. In this order, the DSC curves have been registered with different heating rates, between 5 and 15 degrees/min. The structure of fabricated glasses has been studied by infrared and Raman spectroscopes. The effect of heat treatment on the structural properties was determined. In all glass samples the dominated infrared absorbance band at 800cm(-1) corresponds to asymmetric stretching motions of GeO4 tetrahedra containing bridging (Ge-O(Ge)) and non-bridging (Ge-O(-)) oxygens. Additionally, the influence of heat treatment on the luminescent properties was evaluated. Strong luminescence at 489, 543, 586 and 621nm corresponding to (5)D4?(7)FJ (J=6, 5, 4, 3) transitions was measured. The highest upconversion emission intensity was obtained in the germanate glass co-doped with 0.7Yb2O3/0.7Tb2O3. PMID:24928347

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

2014-10-15

376

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

NASA Astrophysics Data System (ADS)

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

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

2014-12-01

377

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

NASA Astrophysics Data System (ADS)

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

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

2014-05-01

378

Composition dependent frequency upconversion luminescence in Er 3+-doped oxychloride germanate glasses  

NASA Astrophysics Data System (ADS)

Er 3+-doped oxychloride germanate glasses have been synthesized by conventional melting and quenching method. Structural and thermal stability properties were obtained based on the Raman spectra and differential thermal analysis, indicating that PbCl 2 plays an important role in the formation of glass network and has an important influence on the maximum phonon energy and thermal stability of host glasses. Intense green and red emissions centered at 525, 546, and 657 nm, corresponding to the transitions 2H 11/2? 4I 15/2, 4S 3/2? 4I 15/2, and 4F 9/2? 4I 15/2, respectively, were observed at room temperature. With increasing PbCl 2 content, the intensity of green (525 and 546 nm) emissions increases significantly, while the red (657 nm) emission increases slowly. The results indicate that PbCl 2 has more influence on the green emissions than the red emission in oxychloride germanate glasses. The possible upconversion luminescence mechanisms has also been estimated and discussed.

Sun, Hongtao; Yang, Junjie; Zhang, Liyan; Zhang, Junjie; Hu, Lili; Jiang, Zhonghong

2005-03-01

379

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

NASA Astrophysics Data System (ADS)

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

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

2015-02-01

380

Eu3+ ion doped sodium-lead borophosphate glasses for red light emission  

NASA Astrophysics Data System (ADS)

Sodium-lead borophosphate glasses doped with different concentrations of Eu3+ ion are prepared by using the melt quenching technique to study their physical, XRD FTIR and luminescence properties to understand the lasing potentialities of these glasses. The XRD studies confirm the amorphous nature of the glasses. FTIR spectrum indicates the presence of BO3 and PO4 structural units. From the emission spectra, Judd-Ofelt (J-O) intensity parameters have been evaluated from the transition 5D0 ? 7FJ (J = 2 and 4). The evaluated (J-O) intensity parameters have been used to calculate the radiative transition probabilities, luminescence branching ratio and radiative decay times. The intensity ratio (R) value due to 5D0 ? 7F2/5D0 ? 7F1 transition intensity of Eu3+ ions, increase with increasing concentrations suggesting higher asymmetry and covalent bonding character between rare earth ion and oxygen ligands. The chromaticity coordinates were calculated and analyzed with Commission International deI'Eclairage color diagram. The lifetimes of 5D0 metastable state for the samples with different concentrations were also measured and discussed. The predicted and experimental lifetimes for the 5D0 level in sodium lead borophosphate glasses were compared and discussed in detail.

Kiran, Nallamala

2014-05-01

381

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

NASA Astrophysics Data System (ADS)

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

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

2015-01-01

382

Formation of Al-doped ZnO thin films on glass by sol-gel process and characterization  

NASA Astrophysics Data System (ADS)

In this study, pure ZnO and Al-doped ZnO thin films were developed on glass by sol-gel process followed by drying and annealing in air at 170 and 400 °C, respectively. The surface morphology and structural characteristics were determined through scanning electron microscopy, atomic force microscopy and X-ray diffraction. The Fourier transform infrared spectroscopy validated the formation of Al-doped ZnO film on glass substrate. It was evaluated that 1 at% aluminum (Al) doping in ZnO film showed low electrical resistivity and higher charge carrier concentration due to uniformly dispersed regular shape crystallites as compared to pure ZnO and 2 at% `Al'-doped thin films.

Shahid, M. U.; Deen, K. M.; Ahmad, A.; Akram, M. A.; Aslam, M.; Akhtar, W.

2015-03-01

383

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

SciTech Connect

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

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

2005-07-15

384

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

385

2 ?m emission performance in Ho 3+ doped fluorophosphate glasses sensitized with Er 3+ and Tm 3+ under 800 nm excitation  

NASA Astrophysics Data System (ADS)

The spectroscopic properties and energy transfer mechanisms in Ho 3+ doped fluorophosphate glasses sensitized by Er 3+ and Tm 3+ at the 2 ?m region are investigated. The absorption spectra and fluorescence spectra of the Tm-Ho doubly-doped glass system and Er-Tm-Ho triply-doped glass system are measured. According to the absorption spectra, the Judd-Ofelt parameters and spontaneous transition probability are calculated and compared with those of other glass hosts. From the fluorescence spectra, the fluorescence intensity of Er-Tm-Ho glass system at 2.0 ?m is 0.95 and larger than that of the Tm-Ho glass system, which is 0.69. Meanwhile, the 2.0 ?m to 1.8 ?m and 2.0 ?m to 1.53 ?m peak intensity ratios in the Er-Tm-Ho glass system are 8.63 and 22.79, respectively, suggesting sufficient energy transfer between Er 3+, Tm 3+ and Ho 3+ ions. In addition, the pumping schemes and energy transfer mechanisms of Tm-Ho doubly-doped and Er-Tm-Ho triply-doped glasses are discussed. The study indicates that the Er-Tm-Ho triply-doped glass system is a significant sensitized way pumped at 800 nm in fluorophosphate glasses for 2 ?m applications.

Wang, Meng; Yi, Lixia; Wang, Guonian; Hu, Lili; Zhang, Junjie

2009-08-01

386

Optical and spectroscopic characterization of Er3+-Yb3+co-doped tellurite glasses and fibers  

NASA Astrophysics Data System (ADS)

Optical and spectroscopic properties of Er3+-Yb3+ co-doped TeO2-WO3-Nb2O5-Na2O-Al2O3 glasses and fibers were investigated. Emission spectra and fluorescence lifetimes of 4I13/2 level of Er3+ion as a function of rare earth concentration and fiber length were measured in glasses. Results show that the self-absorption effect broadens the spectral bandwidth of 4I13/2?4I15/2 transition and lengthens the lifetime significantly from 3.5 to 4.6 ms. Fibers were fabricated by the rod-in-tube technique using a Heathway drawing tower. The emission power of these Er3+-Yb3+ co-doped Step Index Tellurite Fibers (SITFs; lengths varying from 2 to 60 cm) were generated by a 980 nm diode laser pump and then the emission power spectra were acquired with an OSA. The maximum emission power spectra, within the 1530-1560 nm region, were observed for fiber lengths ranging from 3 to 6 cm. The highest bandwidth obtained was 108 nm for 8 cm fiber length around 1.53 µm.

Narro-García, R.; Desirena, H.; Chillcce, E. F.; Barbosa, L. C.; Rodriguez, E.; De la Rosa, E.

2014-04-01

387

Superbroadband near-IR photoluminescence from Pr3+-doped fluorotellurite glasses.  

PubMed

Praseodymium(Pr3+)-doped fluorotellurite glasses were synthesized and broadband photoluminescence (PL) covering a wavelength range from 1.30 to 1.67 ?m was observed under both 488 and 590 nm wavelength excitations. The broadband PL emission is mainly due to the radiative transition from the manifolds Pr3+: 1D2 to 1G4. The PL line-shape, band width, and lifetime were modified by the Pr3+ dopant concentration, and a quantum efficiency as high as 73.7% was achieved with Pr3+ dopant in a low concentration of 0.05 mol%. The good spectroscopic properties were also predicted by the Judd-Ofelt analysis, which indicates a stronger asymmetry and covalent bonding between the Pr3+ sites and the matrix lifgand field. The large stimulated emission cross-section, long measured lifetime, and broad emission bandwidth confirm the potential of the Pr3+-singly doped fluorotellurite glass as broadband luminescence sources for the broadband near-infrared optical amplifications and tunable lasers. PMID:22418137

Zhou, Bo; Tao, Lili; Tsang, Yuen H; Jin, Wei; Pun, Edwin Yue-Bun

2012-02-13

388

Magnetooptics and magnetic ordering in ferrite nanoparticles in glass doped with iron and rare-earth elements  

Microsoft Academic Search

Magnetic circular dichroism and X-ray diffraction were used to investigate the structure and magnetooptical properties of\\u000a nanoparticles formed in potassium-aluminum-germanium-boron glass doped with iron and rare-earth elements. It is demonstrated\\u000a that in thermally processed glass, the main magnetic phase of the formed nanoparticles is ?-Fe2O3 maghemite.

O. S. Ivanova; I. S. Edelman; R. D. Ivantsov; V. N. Zabluda; S. A. Stepanov; S. M. Zharkov; G. M. Zeer; Ya. V. Zubavichus; A. A. Veligzhanin; J. Curely

2011-01-01

389

Erbium\\/ytterbium co-doped optical waveguide amplifier in soda-lime glass by silver ion exchange  

Microsoft Academic Search

We have described the experimental results of the gain characteristics of Er\\/Yb co-doped optical waveguide amplifiers in soda-lime glasses fabricated by the silver ion exchange method. Silica glasses are attractive because of their superior chemical resistance and compatibility to optical fibers. Measured absorption and fluorescence spectra are shown. A net gain of 4.34 dB and gain coefficient of 1.55 dB\\/cm

K. Iiyama; K. Hongo; F. Demura; S. Takamiya

1999-01-01

390

Formation of Pt\\/Pb nanoparticles by electrodeposition and redox replacement cycles on fluorine doped tin oxide glass  

Microsoft Academic Search

A two-stage approach that combines electrodeposition with redox replacement has been used to deposit Pt\\/Pb nanoparticles on fluorine doped tin oxide (FTO) glass. The deposition takes place by cycling between the two steps in a single electrolyte bath containing both Pb2+ and Pt2+ ions. In the first step, Pb is electrodeposited on FTO glass at a potential E1 and in

K. a b Yliniemi; D. b Wragg; B. P. a Wilson; H. N. b McMurray; D. A. b Worsley; P.c Schmuki; K. a Kontturi

2013-01-01

391

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

NASA Astrophysics Data System (ADS)

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

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

2014-05-01

392

Structure and luminescence spectra of lutetium and yttrium borates synthesized from ammonium nitrate melt  

Microsoft Academic Search

Lutetium and yttrium borates doped with europium, terbium, gadolinium, etc. have been synthesized by dissolving initial oxides and nitrates in ammonium nitrate melt and thermal decomposition of the solvent. Annealings in the range of 500–1100°C modified the dimensions of the grains from 2 to 3nm to more than 100nm. Significant dependence of the structure of lutetium borate on slight doping

Nikolay V. Klassen; Semion Z. Shmurak; Ivan M. Shmyt’ko; Galina K. Strukova; Stephen E. Derenzo; Marvin J. Weber

2005-01-01

393

Towards mid-infrared fiber-lasers: rare earth ion doped, indium-containing, selenide bulk glasses and fiber  

NASA Astrophysics Data System (ADS)

Chalcogenide glasses are promising materials for mid-infrared (IR) fiber lasers (i.e. 3 - 25 ?m wavelength range). These glasses exhibit low phonon energies, together with large refractive indices, rare earth (RE-) ion solubility and sufficient mechanical and chemical robustness. Optical quality of the fiber is key. Gallium is known to promote RE-ion solubility in chalcogenide glasses, probably forming a [Pr(III)] - Se - [Ga(III)] associated type complex. Here, indium is investigated as an alternative additive to gallium in Pr3+-doped Ge-As-Se chalcogenide glasses. Indium has the same outer electronic structure as gallium. Moreover, indium has the advantage of being heavier than gallium, potentially promoting a lower phonon-energy, local environment of the RE-dopant. Zero to ~2000 ppmw (nominal parts per million by weight) Pr3+- doped Ge-As-In-Se bulk glasses are prepared using the melt-quench method. ~500 ppmw Pr3+- doped Ge-As-In-Se, optically-clad fiber is realized via fiber-drawing of extruded fiberoptic preforms. Fiber absorption and emission spectra are collected and compared with those of the bulk glasses.

Sakr, H.; Tang, Z.; Furniss, D.; Sojka, L.; Moneim, N. A.; Barney, E.; Sujecki, S.; Benson, T. M.; Seddon, A. B.

2014-02-01

394

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

PubMed

The spectroscopic properties and thermal stability of Er3+-doped Bi2O3-B2O3-Ga2O3 glasses are investigated experimentally. The effect of Ga2O3 content on absorption spectra, the Judd-Ofelt parameters Omega t (t=2, 4, 6), fluorescence spectra and the lifetimes of Er3+:4I 13/2 level are also investigated, and the stimulated emission cross-section is calculated from McCumber theory. With the increasing of Ga2O3 content in the glass composition, the Omega t (t=2, 4, 6) parameters, fluorescence full width at half maximum (FWHM) and the 4I 13/2 lifetimes of Er3+ first increase, reach its maximum at Ga2O3=8 mol.%, and then decrease. The results show that Er3+-doped 50Bi2O3-42B2O3-8Ga2O3 glass has the broadest FWHM (81nm) and large stimulated emission cross-section (1.03 x1 0(-20)cm2) in these glass samples. Compared with other glass hosts, the gain bandwidth properties of Er+3-doped Bi2O3-B2O3-Ga2O3 glass is better than tellurite, silicate, phosphate and germante glasses. In addition, the lifetime of 4I 13/2 level of Er(3+) in bismuth-based glass, compared with those in other glasses, is relative low due to the high-phonon energy of the B-O bond, the large refractive index of the host and the existence of OH* in the glass. At the same time, the glass thermal stability is improved in which the substitution of Ga2O3 for B2O3 strengthens the network structure. The suitability of bismuth-based glass as a host for a Er3+-doped broadband amplifier and its advantages over other glass hosts are also discussed. PMID:17350330

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

2007-11-01

395

Structural and luminescence studies on Dy3+ doped lead boro-telluro-phosphate glasses  

NASA Astrophysics Data System (ADS)

This paper reports results obtained on the structural and luminescence properties of Dy3+doped lead boro-telluro-phosphate glasses prepared following the melt quenching technique. FTIR spectra exhibit the presence of B-O vibrations, P-O-P symmetric vibrations and Te-O stretching modes of TeO3 and TeO6 units. The metal-ligand bond was identified through UV-vis-NIR absorption spectra and to determine the band tailing parameter, direct and indirect band gap energy of the prepared glasses. The Judd-Ofelt (JO) intensity parameters (?2, ?4 and ?6), experimental and theoretical oscillator strengths were also determined and reported. Luminescence measurements were made to determine the transition probability (A), stimulated emission cross-section (?PE) and branching ratio (?R) for the transitions that include 4F9/2?6H11/2, 6H13/2 and 6H15/2 bands. The effect of Dy3+ ion concentration on the intensity ratio of yellow to blue emission bands has also been studied and reported. The lifetime corresponding to the 4F9/2 level of the title glasses has been found to decrease with the increase in Dy3+ ion concentration. The chromaticity coordinates (x,y) have been estimated from the luminescence spectra and the suitability of title glasses for white light applications has been analyzed using CIE chromaticity diagram. The variation of optical properties with the concentration of dysprosium oxide content in the glasses have been studied and reported.

Selvi, S.; Venkataiah, G.; Arunkumar, S.; Muralidharan, G.; Marimuthu, K.

2014-12-01

396

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

PubMed Central

Objectives Our goal was to characterize the response of human mesenchymal stem cells (hMSCs) to a niobium-doped fluorapatite-based glass-ceramic (FAp). Methods The glass was prepared by twice melting at 1525°C for 3h, and cast into cylindrical ingots later sectioned into discs and heat-treated to promote crystallization of fluorapatite submicrometer crystals. Tissue culture polystyrene (TCP) was used as control. The surface of the FAp discs was either left as-heat treated, ground or etched. Initial cell attachment was assessed at 3h. Proliferation and alkaline phosphatase (ALP) expression data was collected at days 1, 4, and 8. Cell morphology was examined using SEM, at days 2 and 4. Mineralization was evaluated by Alizarin Red staining and SEM. Results Initial cell attachment on as heat-treated, etched, or ground surfaces was similar to that of the positive control group (p>0.05). The percentage of area covered by living cells increased significantly on as heat-treated, etched, or ground surfaces between days 1 and 8 (p<0.05). There was no significant difference amongst groups in cell coverage at day 8, compared to TCP control. SEM revealed well spread polygonal cells with numerous filopodia, either attached to the ceramic surface or connected to neighboring cells. ALP expression at day 8 was significantly higher in osteogenic media compared to growth media on both FAp and control. FAp discs stained positively with alizarin red and calcium-rich mineralized granules associated with fibrils were observed by SEM at day 35. Significance hMSCs displayed excellent attachment, proliferation, and differentiation on niobium-doped FAp glass-ceramic. PMID:22078764

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

2011-01-01

397

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

PubMed Central

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

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

2013-01-01

398

[Influence of erbium ion concentration on Judd-Ofelt parameters of Er3+ -doped tellurite glass].  

PubMed

Er3+ -doped tellurite glasses with four different concentrations were fabricated, and the oscillator strength of Er3+ in the tellurite glasses were calculated through the absorption spectra of the glasses. The Judd-Ofelt intensity parameter omega i, spontaneous transition probability A, fluorescence branching ratio beta, and radiative lifetime tau rad of Er3+ were calculated on the basis of Judd-Ofelt theory, and the effect of the erbium ion concentration on the above optical parameters was also discussed. The fluorescence spectra of Er3+: (4)I(13/2)--> (4)I(15/2) transition and the lifetime of Er3+: (4)I(13/2) level of the samples were measured. The stimulated emission cross-section of (4)I(13/2)--> (4)I(15/2) transition of the samples was finally calculated by using McCumber theory. The results show that with the increase in the Er3+ concentration, the oscillator strength and spontaneous transition probability A of Er3+ increase, while the fluorescence branching ratio beta of Er3+ shows little difference. The stimulated emission cross-section of Er3+: (4)I(13/2)--> (4)I(15/2) transition of the samples changes slightly with the increase in the Er3+ concentration. All the fluorescence effective line widths for the four different Er3+ concentration samples are nearly 50 nm. PMID:16830740

Zhou, Gang; Dai, Shi-xun; Yu, Chun-lei; Zhang, Jun-jie; Hu, Li-li; Jiang, Zhong-hong

2006-03-01

399

Fluorescence dynamics of Tb 3+ and Tb 3+/Ho 3+ doped phosphate glasses  

NASA Astrophysics Data System (ADS)

UV absorption and fluorescence analysis of Tb 3+ in phosphate glass is carried out by Judd-Ofelt method with emphasis on the 5D?7F lasing transition. Branching ratios, peak emission cross-sections for 5D?7( level of Tb 3+ are calculated using Judd-Ofelt intensity parameters. Furthermore, fluorescence dynamics of the 5D level of Tb 3+ ion in phosphate glasses co-doped with Ho 3+ were experimentally investigated with classical Forster-Dexter model for direct cross-relaxation type energy transfer between Tb 3+ (donor) and Ho 3+ (acceptor). The energy transfer rates between Tb 3+ and Ho 3+ in phosphate glasses were calculated on the basis of experimental measurements. These measurements were performed for 1 wt.% of Tb 3+ and Ho 3+ concentration ranging from 0 to 3 wt.%. The results show that energy transfer occurs between the 5D 4 terbium and 5F 3 holmium levels and is a phonon-assisted dipole-dipole interaction.

Rai, S.; Hazarika, S.

2008-05-01

400

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

SciTech Connect

Radiometrically calibrated spectroscopic techniques employing an integrating-sphere detection system have been used to determine the fluorescence quantum efficiencies for two commercially available Nd{sup 3+}-doped phosphate laser glasses, LG-750 and LG-760. Quantum efficiencies and fluorescence lifetimes were measured for samples with various neodymium concentrations. It is shown that the effects of concentration quenching are accurately described when both resonant nonradiative excitation hopping (the Burshtein model) and annihilation by cross relaxation are accounted for by Foerster--Dexter dipole--dipole energy-transfer theory. The Foerster--Dexter critical range for nonradiative excitation hopping was found to be {ital R}{sub DD}=11 A, while the critical range for cross relaxation was close to {ital R}{sub DA}=4 A in these glasses. The quantum efficiency at low Nd{sup 3+} concentrations was (92{plus minus}5)%, implying a nonradiative relaxation rate of 210{plus minus}150 s{sup {minus}1} for isolated ions. Improved values for the radiative lifetimes and the stimulated emission cross sections for these glasses were also deduced from the measurements.

Caird, J.A.; Ramponi, A.J.; Staver, P.R. (Lawrence Livermore National Laboratory, University of California, P.O. Box 808, Livermore, California 94551-0808 (US))

1991-07-01

401

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

PubMed Central

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

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

2012-01-01

402

Structural and spectroscopic properties of Eu3+-doped zinc fluorophosphate glasses  

NASA Astrophysics Data System (ADS)

Zinc fluorophosphate (ZFPEu: P2O5-K2O-Al2O3-ZnF2-LiF-Eu2O3) glasses doped with different Eu3+ ion concentrations have been prepared and characterized through DTA, Raman, absorption, luminescence, excitation, phonon side band spectra and decay measurements at room temperature. An intense red luminescence has been observed due to 5D0 ? 7F2 transition of Eu3+ ions in these glasses. Raman and phonon side band spectroscopic techniques have been used to investigate the local structure around Eu3+ ions and phonon energy of the host, respectively. The analysis of optical intensities based on absorption and luminescence spectra has been performed under different constraints using Judd-Ofelt (JO) theory. The JO intensity parameters have been used to predict the radiative properties such as radiative lifetime, branching ratio, and stimulated emission cross-section for the 5D0 ? 7FJ (J = 0-6) transitions. Decay rates for the 5D0 level of Eu3+ ions has been found to be single exponential for all concentrations. Luminescence properties of the 5D0 ? 7F2 transition of Eu3+ ion revealed that the present ZFPEu glasses may be useful for developing visible red lasers as well as optical display devices at around 611 nm.

Vijaya, N.; Jayasankar, C. K.

2013-03-01

403

Application of Cu2O-doped phosphate glasses for bandpass filter  

NASA Astrophysics Data System (ADS)

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

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

2014-09-01

404

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

NASA Astrophysics Data System (ADS)

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

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

2009-11-01

405

Spectral investigations of Sm3+ doped lead bismuth magnesium borophosphate glasses  

NASA Astrophysics Data System (ADS)

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

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

2012-09-01

406

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

NASA Astrophysics Data System (ADS)

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

Dorosz, Dominik; Zmojda, Jacek; Kochanowicz, Marcin

2014-07-01

407

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

NASA Astrophysics Data System (ADS)

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

Gong, Hui; Li, Chengfu

1997-07-01

408

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

PubMed

We investigate the relation of ion-exchange treatment and laser conditioning of a glass surface. The surface of Nd-doped phosphate laser glass was preirradiated with a cw CO(2) laser and strengthened by the ion-exchange treatment. It is shown that residual compressive stress occurs on the surface as peak-to-valley roughness and the appearance of microcracks decreases. Damage threshold of the glass surface increases by a factor of 1.7-3. The mechanism of laser conditioning is consistent with that of the ion-exchange treatment. PMID:18259298

Gong, H; Li, C

1997-07-20

409

Study of luminescence properties of novel Er3+ single-doped and Er3+/Yb3+ co-doped tellurite glasses.  

PubMed

The novel Er(3+) single-doped and Er(3+)/Yb(3+) co-doped tellurite glasses were prepared. The effect of Yb(2)O(3) concentration on absorption spectra, emission spectra and upconversion spectra of glasses were measured and investigated. The emission intensity, fluorescence full width at half maximum (FWHM) and upconversion luminescence of Er(3+) go up with the increasing concentration of Yb(3+) ions. The maximum FWHM of (4)I(13/2) --> (4)I(15/2) transition of Er(3+) is approximate 77 nm for 1.41 x 10(21)ions/cm(3) concentration of Yb(3+)-doped glass. The visible upconversion emissions at about 532, 546 and 659 nm, corresponding to the (2)H(11/2) --> (4)I(15/2), (4)S(3/2) --> (4)I(15/2) and (4)F(9/2) --> (4)I(15/2) transitions of Er(3+), respectively, were simultaneously observed under the excitation at 970 nm. Subsequently, the possible upconversion mechanisms and important role of Yb(3+) on the green and red emissions were discussed and compared. The results demonstrate that this kind of tellurite glass may be a potentially useful material for developing potential amplifiers and upconversion optical devices. PMID:15741130

Gao, Yuan; Nie, Qiu-Hua; Xu, Tie-Feng; Shen, Xiang

2005-04-01

410

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

SciTech Connect

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

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

1996-05-01

411

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

NASA Astrophysics Data System (ADS)

The Sm3+-doped lead barium zinc lithium fluoroborate (LBZLFB) glasses of composition 20PbO + 5BaO + 5ZnO + 10LiF + (60 - x) B2O3 + xSm2O3, (where x = 0.1, 0.5, 1.0, 1.5 and 2.0 mol%) have been prepared by conventional melt quenching technique and their structural and spectroscopic behavior were studied and reported. The amorphous nature of these glass samples was confirmed with XRD studies. The FT-IR and FT-Raman spectra reveal that, the glasses contain BO3, BO4, non-bridging oxygen and strong OH bonds. The bonding parameters and the oscillator strengths were determined from the absorption spectra. These parameters have been used to obtain the Judd-Ofelt intensity parameters. Using these intensity parameters various radiative and laser properties were predicted. The values of J-O intensity parameters suggested an increase in the degree of symmetry of the local ligand field at Sm3+ sites. The decay rates for the 4G5/2 level of Sm3+ ions have been measured and are found to be single exponential at lower concentrations (<1.0 mol%) and turn into non-exponential at higher concentrations (?1.0 mol%), due to energy transfer through cross-relaxation. From the emission characteristic parameters of 4G5/2 level, it is concluded that the LBZLFB glasses could be useful for photonic devices like visible lasers, fluorescent display devices and optical amplifiers, operated in the visible region.

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

2013-02-01

412

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

NASA Astrophysics Data System (ADS)

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

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

2014-05-01

413

Stability against crystallization and spectroscopic properties of Tm 3+ doped fluorophosphate glasses  

NASA Astrophysics Data System (ADS)

Fluorophosphate glasses with various content of Al(PO 3) 3 were prepared. With the increment of Al(PO 3) 3 content, density decreases while refractive index increases, and transition temperature, crystallization peak temperature and melt temperature increase which were suggested by differential scanning calorimetry. These glasses exhibit the best stability against crystallization with 7-9 mol% Al(PO 3) 3 content. Normalized Raman spectra were used to analyze structure and phonon state. The increment of Al(PO 3) 3 content does not affect phonon energy but results in the augment of phonon density. Absorption spectra were measured. 3H 6 ? 3F 4 transition exhibits absorption at L band of the third communication window. Compared with the energy of Tm 3+ excited states in other glass system, 3F 4 energy of Tm 3+ in these glasses is considerable higher and 3H 4 energy is considerable lower, and it can be predicted that emission band of 3H 4 ? 3F 4 transition is close to the amplified band of gain-shift Tm 3+ doped fiber amplifier. Analyses of Judd-Ofelt theory suggest when Al(PO 3) 3 content is no more than 7 mol%, Judd-Ofelt parameters ?t and the lifetime of 3H 4 energy level of Tm 3+ vary little with the increment of Al(PO 3) 3 content, and when Al(PO 3) 3 content is more than 7 mol%, ?2 and ?6 increase and radiative lifetime of 3H 4 energy level of Tm 3+ drops sharply with the increment of Al(PO 3) 3 content.

Liao, M. S.; Fang, Y. Z.; Sun, H. T.; Hu, L. L.

2007-03-01

414

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

NASA Astrophysics Data System (ADS)

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

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

2014-11-01

415

Effect of Ce2O3 on the 1.53 ?m spectroscopic properties in Er3+-doped tellurite glasses  

NASA Astrophysics Data System (ADS)

Er3+/Ce3+ co-doped tellurite-based glasses with composition of TeO2-ZnO-Na2O are prepared by high- temperature melt-quenching technique. Effects of Ce2O3 content on the 1.53 ?m band fluorescence spectra and fluorescence lifetime of Er3+ are measured and investigated. It is found that the tellurite glass containing Ce2O3 with molar concentration of 0.25% exhibits an increment of 13% in 1.53 ?m fluorescence intensity and an increment of 15% in the 4I13/2 level lifetime. The results indicate that the prepared tellurite-based glass with a suitable Er3+/Ce3+ codoping concentration is an excellent gain medium applied for broadband Er3+-doped fiber amplifier (EDFA) pumped with a 980 nm laser diode.

Zheng, Shi-chao; Zhou, Ya-xun; Xue, Rui

2015-03-01

416

Effects of F- on the optical and spectroscopic properties of Yb3+/Al3+-co-doped silica glass  

NASA Astrophysics Data System (ADS)

Yb3+/Al3+-co-doped silica glasses with different F- content were prepared in this work by sol-gel method combined with high temperature sintering. XRF, FTIR and XPS methods were used to confirm the presence of F-. The effects of F- on the optical and spectroscopic properties of these glasses have been investigated. It is worth to notice that the F-/Si4+ mass ratio equal to 9% is a significant value showing a real change in the variation trends of numerous following parameters: refractive index, UV absorption edge, absorption and emission cross sections, scalar crystal-field NJ and fluorescent lifetimes. Furthermore, introduction of F- can adjust the refractive index of Yb3+/Al3+-co-doped silica glass and it is useful for large mode area (LMA) fibers.

Xu, Wenbin; Yu, Chunlei; Wang, Shikai; Lou, Fengguang; Feng, Suya; Wang, Meng; Zhou, Qinling; Chen, Danping; Hu, Lili; Guzik, Malgorzata; Boulon, Georges

2015-04-01

417

Survey and research on up-conversion emission character and energy transition of Yb3+/Er3+/Tm3+ co-doped phosphate glass and glass ceramic  

NASA Astrophysics Data System (ADS)

By conventional high-temperature melting method, Yb3+/Er3+/Tm3+ co-doped phosphate glass was synthesized. After annealing the precursor glass, the phosphate glass ceramic (GC) was obtained. By measuring the X-ray diffraction (XRD) spectrum, it is proved that the LiYbP4O12 and Li6P6O18 nano-crystals have existed in the phosphate GC. The up-conversion (UC) emission intensity of the GC is obvious stronger compared to that of the glass. The reason is that the shorter distance between rare earth ions in the glass ceramic increases the energy transitions from the sensitized ions (Yb3+) to the luminous ions (Er3+ and Tm3+). By studying the dependence of UC emissions on the pump power, the 523 and 546 nm green emissions of Er3+ ions in the glass are two-photon processes. But in the glass ceramic, they are two/three-photon processes. The phenomenon implies that a three-photon process has participated in the population of the two green emissions. Using Dexter theory, we discuss the energy transitions of Er3+ and Tm3+. The results indicate the energy transition of Tm3+ to Er3+ is very strong in the GC, which changes the population mechanism of UC emissions of Er3+.

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

2012-11-01

418

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

NASA Astrophysics Data System (ADS)

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

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

2014-06-01

419

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

SciTech Connect

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

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

2012-11-15

420

Study of spatial rings in TPPOH4 doped in boric acid glass  

NASA Astrophysics Data System (ADS)

Single beam optical nonlinearity is studied in TPPOH4 doped in boric acid sandwiched films between two microscope glass slides at three different molar concentrations (4×10?4M, 1×10?4M, 5×10?5M). It shows absorption peak at 700nm with bandwidth of 70nm. We have used diode laser output at 671nm to probe resonant optical nonlinearities. We have observed interesting phenomena of formation of spatial concentric rings centered on the z-axis of the sample. To our knowledge this is first such observation of spatial rings in these systems. We have carried out studies to separate the contribution to the ring formation due to absorptive/refractive optical nonlinearity and the thermal nonlinearity.

Rao Allam, Srinivasa; Dar, Mudasir H.; Venkatramaiah, N.; Venkatesan, R.; Sharan, Alok

2015-02-01