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Sodium borate and fluoroborate glasses doped with trivalent samarium (Sm3+) were prepared and their detailed spectroscopic analysis was carried out. The FTIR spectra reveal that, the glasses contain BO3, BO4, non-bridging oxygen and strong OH− bonds. From the optical absorption spectra, Judd-Ofelt intensity parameters (Ωλ, λ=2, 4 and 6) have been evaluated and are in turn used to predict radiative properties such as radiative transition probability (A), stimulated emission cross section () and branching ratios (βR) for the excited levels of Sm3+ ions in sodium borate and sodium fluoroborate glasses. The dependence of the spectral characteristics of Sm3+ ions due to compositional changes have been examined and reported. The value is found to decrease with the decrease in the sodium content in the glass. The decay from the 4G5/2 level is found to be non-exponential indicating a cross-relaxation among the Sm3+ ions. 相似文献
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Boro-tellurite glasses with the composition (69-x)H3BO3+xTeO2+15MgCO3+15K2CO3+1Sm2O3 (where x=0, 10, 20, 30 and 40 wt%) doped with trivalent samarium have been prepared and their structural and spectroscopic behavior were studied and reported. The FTIR spectra reveal the presence of BO3 and BO4 non-bridging oxygen as well as strong OH− bonds in the prepared glasses. Through the optical absorption spectra, Judd-Ofelt intensity parameters (Ωλ, λ=2, 4 and 6) have been evaluated and the same is in turn used to predict radiative properties such as radiative transition probability (A), stimulated emission cross-section () and branching ratios (βR) for the excited levels of Sm3+ ions corresponding to 4G5/2→6H5/2, 4G5/2→6H7/2, 4G5/2→6H9/2 and 4G5/2→6H11/2 transitions. Structural and spectral dependence of the Sm3+ ions due to the compositional changes have been examined and reported. The lifetime of the 4G5/2 level is found to be non-exponential for all the prepared glasses indicating a cross-relaxation among the Sm3+ ions. The structural and spectroscopic results corresponding to compositional changes have been compared with the similar studies and reported. 相似文献
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R.R. Reddy Y. Nazeer Ahammed K. Rama Gopal S. Buddhudu 《Journal of Quantitative Spectroscopy & Radiative Transfer》2003,77(2):149-163
Absorption and photoluminescence spectra of Sm3+ and Dy3+ doped alkali fluoroborate glasses of the composition 90.5% B2O3+4% AlF3+5% MF+0.5% LnF3 (M=Li, Na, K and Ln=Sm, Dy) have been reported. On excitation, with , the Sm3+ glasses are found to be orange fluorescent in color and richness of that color is high in the Na+ glass, compared to Li+ and K+ glasses. Similarly, on excitation with , the Dy3+ glasses are fluorescent yellow in color and that color is richer in the K+ glass. 相似文献
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Y.C Ratnakaram D Thirupathi Naidu J.L Rao 《Journal of Physics and Chemistry of Solids》2003,64(12):2487-2495
The effect of mixed alkalis on the optical absorption spectra of Tm3+ in xNa2O·(30−x)K2O·70B2O3 glasses has been studied. The optical band gap values (Eopt) for both direct and indirect transitions have been obtained using Davis and Mott theory. Spectroscopic parameters like Racah (E1, E2 and E3), spin-orbit (ξ4f) and Judd-Ofelt intensity parameters (, and ) have been calculated for different x values. Radiative transition probabilities (Arad), radiative lifetimes (τR), branching ratios (β), integrated absorption cross sections (Σ) and multiphonon relaxation rates (WMPR) are calculated for certain excited states of Tm3+ ion. The observed trends in the above parameters as a function of x in these borate glasses have been discussed keeping in view the effect of mixed alkalies in borate glasses. Certain potential lasing transitions have been identified for laser action among the various transitions of Tm3+ in these mixed alkali borate glasses. 相似文献
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R.T. Karunakaran K. Marimuthu S. Surendra Babu S. Arumugam 《Journal of luminescence》2010,130(6):1067-7433
Thermal, structural and optical properties of Dy3+-doped alkali fluoroborate glasses with composition (in mol%), 49B2O3+25XO+25NaF+1Dy2O3 (where X=Li2, Na2, K2, Mg and Ca), have been investigated. Thermal analysis revealed the homogeneous formation of the glasses. The FTIR spectra reveal that the glasses contain BO3, BO4 non-bridging oxygen atoms and strong OH− bonds. From the optical absorption spectra, Judd-Ofelt intensity parameters (Ωλ, λ=2, 4 and 6) have been evaluated and are in turn used to predict radiative properties such as radiative transition probability (A), stimulated emission cross-section () and branching ratios (βR) for the excited levels of Dy3+ ions in alkali fluoroborate glasses. The dependence of the spectral characteristics of Dy3+ ions due to compositional changes has been examined and reported. 相似文献
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Qinghua Zeng 《Journal of luminescence》2003,101(3):167-174
The temperature-dependent luminescence of Sm2+ ions in MBPO5 was studied. At low temperature, Sm2+ in this series shows 4f6→4f6 luminescence with only a single emission line observed for the transition, revealing that only one crystallographic cationic site is available for Sm2+ in all the hosts. With increasing temperature, the emission intensity of the transition increases whereas that of the transitions decreases. The transitions of Sm2+ were observed in BaBPO5 and its intensity increases with increasing temperature. At , a broad band of the 4f55d→4f6 luminescent transition of Sm2+ in SrBPO5 and BaBPO5 with maximum at appears due to the thermal population. The lifetime of the transition was recorded at different temperatures, showing a single exponential decay for Sm2+ in SrBPO5 and BaBPO5 but a non-single-exponential decay in CaBPO5. 相似文献
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Sm3+-doped calcium fluoride bismuth borate glasses were prepared and characterized optically and the oscillator strengths and Judd–Ofelt parameters for the glass containing 1.5 mol% of Sm2O3 were calculated. Density and optical absorption, transmission and the emission spectra were measured. The values of Judd–Ofelt parameters suggested an increase in the degree of asymmetry the local ligand field at Sm3+ sites. The optical band gap energy, band tailing parameter and Urbach's energy were calculated for all glass samples. It was found that with increasing the concentration of Sm2O3 content the values of the optical band gap energy decrease whereas Urbach's energy increases. Absorption and excitation spectra indicate that commercial UV and blue laser diodes, blue and bluish-green LEDs and Ar+ optical laser are powerful excitation sources for Sm3+ visible fluorescence in the glass. 相似文献
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Infrared-to-visible upconversion processes and Judd Ofelt intensity parameters were analyzed for Ho3+ singly doped and Ho3+/Yb3+ co-doped Al(NO3)3-SiO2 glasses with a fixed Ho3+ and Yb3+ concentrations prepared by sol-gel method. Blue and intense green upconversion emissions centered at 467 and 538 nm, corresponding to the and transitions, respectively, were observed under 800 nm excitation. The analysis of the dynamics of upconversion emissions suggest excited state absorption, energy transfer and back transfer as the possible causes for the observed transitions. Significant enhancement of upconversion intensities in Ho3+/Yb3+ co-doped glass compared to the Ho3+ singly doped one confirms efficient energy transfer between Yb3+ and Ho3+ ions. Intense upconversion emissions shown by the glasses in the present study indicate their potential in upconversion device applications. 相似文献
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Erbium-doped (GeS2)x(Ga2S3)100−x (x=75, 80, 85, 90 mol%) glasses have been characterized by some basic parameters, which are important from a practical point of view. The influence of Er by introduction of 0.3, 0.6, and 0.9 mol% Er2S3 on the properties has been studied. The glasses have relatively high glass transition temperatures and high thermal stability, the maximal being at x=80 (the difference between the crystallization and glass transition temperatures has been found to be 150 °C. The values of Vickers microhardness and density increase with increasing GeS2 content, slightly depending on the presence of the Er3+ ions. The distribution and changes of the structural units, caused by addition of Ga2S3 and Er2S3 to GeS2, have been specified by the Raman scattering in the range 50-550 cm−1. The intensity dependence of the luminescence on glass composition has been evaluated. The glasses have shown a good chemical durability and their resistance to the moisture is relatively high. The obtained results have supported possible applications of these glasses in rare-earth doped devices. 相似文献
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K. Naito 《Solid State Communications》2004,131(5):289-294
Transparent Er3+-doped bulk nanocrystallized (size of nanocrystals: ∼40 nm) glasses of 15K2O·15Nb2O5·70TeO2·0.5Er2O3 and 10BaO·10Gd2O3·80TeO2·0.5Er2O3 are prepared, and the Judd-Ofelt parameters, (t=2, 4, 6), of Er3+ are evaluated from optical absorption spectra. The change in the molar polarizability due to the nanocrystallization is small in both samples, but a clear decrease in the mean atomic volume due to the nanocrystallization, i.e. more close atom packing, is observed. In both systems, a large decrease is observed in the parameter due to the nanocrystallization, indicating that the degree of the site symmetry of Er3+ ions in nanocrystallized glasses is much higher than that in the precursor glasses. The decrease in the and parameters due to the crystallization is small, suggesting that the covalency of Er3+-O bonds in nanocrystals is not so different from that in the precursor glasses. 相似文献
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A. Thulasiramudu 《Journal of Quantitative Spectroscopy & Radiative Transfer》2006,97(2):181-194
We have developed a new series of zinc lead borate (ZLB) glasses by varying ZnO content, to enhance UV transmission, in the chemical composition of xZnO-15PbO-(85−x)B2O3, where x=0, 5, 10, 15, 20, 25, 30, 35, 40 and 45 mol% ZnO. From the measurement of UV absorption spectra both the direct and indirect band gaps have been evaluated. Also different physical properties of a reference glass of 45ZnO-15PbO-40B2O3 have been studied. From the measurement of refractive indices at six different wavelengths, Cauchy's constants (A=1.578743209; and ) have been computed and a satisfactory correlation has been achieved between the theoretical and the experimental results. Absorption spectra of Cu2+(45−x)ZnO-15PbO-40B2O3 (where x=0.1, 0.2, 0.5 and 1.0 mol%) have shown two absorption bands at 428 nm (2B1g→2Eg) and 777 nm (2B1g→2B2g). Emission spectra of (1.0 mol%) Cu2+:ZLB have revealed two emission transitions at 400 and 493 nm with excitations at 288 and 316 nm. 相似文献
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Peimin Guo 《Journal of luminescence》2003,105(1):61-67
Novel phosphors of or Bi3+ doped Gd2GeO5 were synthesized and their photoluminescent and cathodoluminescent properties were investigated. (Gd1−xEux)2GeO5 and (Gd1−xTbx)2GeO5 formed continuous solid solution in the range of x=0.0-1.0. Gd2GeO5:Eu3+ and Gd2GeO5:Bi3+ presented bright red and blue luminescence for both UV and cathode ray excitation, respectively. While Gd2GeO5:Tb3+ gave bright green cathodoluminescence. In all three phosphors, the energy transfer from Gd3+ to activators (e.g. or Bi3+) occurred. 相似文献
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