共查询到20条相似文献,搜索用时 15 毫秒
1.
Tirtha Som 《Journal of luminescence》2008,128(12):1989-1996
A new antimony-based glass system (K2O-B2O3-Sb2O3) having low phonon energy (about 600 cm−1) doped with Sm3+ ions has been developed. Infrared reflection spectroscopic (IRRS) studies have been employed to establish its low phonon energy. Ultraviolet-Visible-near infrared (UV-Vis-NIR) absorption and photoluminescence upconversion properties with the spectrochemistry of the 15K2O-15B2O3-70Sb2O3 (mol%) glasses have been studied doping with different concentrations (0.1-1.0 wt%) of Sm2O3. UV-Vis-NIR absorption band positions have been justified with quantitative calculation of nephelauxetic parameter and covalent bonding characteristics of the host. NIR to visible upconversion has been investigated by exciting at 949 nm at room temperature. Three upconverted bands originating from the 4G5/2→6H5/2, 4G5/2→6H7/2 and 4G5/2→6H9/2 transitions are found to be centered at 566 (green, weak), 602 (orange, weak) and 636 (red, remarkably strong) nm, respectively. These bands have been explained from the evaluation of the absorption, normal (downconversion) fluorescence and excitation spectra. The upconversion processes have been explained by the excited state absorption (ESA), energy transfer (ET) and cross-relaxation (CR) mechanisms involving population of the metastable (storage) energy level (4G5/2) by multiphonon deexcitation effect. It is evident from the IRRS study that the upconversion phenomena are expedited by the low multiphonon relaxation rate in antimony glasses owing to their low phonon energy (602 cm−1, the main and highest intensity Sb-O-Sb stretching band) which is very close to that of fluoride glasses (500-600 cm−1). 相似文献
2.
Broadband and upconversion properties were studied in Er3+/Yb3+ co-doped fluorophosphate glasses. Large Ω6 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 Ω6 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 Yb3+:Er3+ ratio and Er3+ concentration, and the corresponding calculated lifetime of 4F9/2 and 4S3/2 states for red and green upconversion samples proves this conclusion. The upconversion mechanism is also discussed. 相似文献
3.
In this paper, we report the near-infrared luminescence from the Er3+/Yb3+, Tm3+/Yb3+, Er3+/Tm3+ and Nd3+ ions-doped TeO2-ZnO-B2O3-Li2O-Na2O glasses for optical amplification. The X-ray diffraction (XRD) and differential scanning calorimetry (DSC) profiles of the host glass matrix have been carried out. From the DSC thermogram, glass transition (Tg), crystallization (Tc) and melting (Tm) temperatures have been evaluated. The near-infrared spectra of Er3+/Yb3+, Tm3+/Yb3+, Er3+/Tm3+ and Nd3+ ions-doped glasses have shown full-width at half-maxima (FWHM) around 58, 127, 87 and 35 nm, respectively. These glasses with better thermal stability and broad near-infrared emissions should have potential applications in broadly tunable laser sources and broadband optical amplification at low-loss telecommunication windows. 相似文献
4.
We investigate the energy transfer between Er3+/Ho3+ in tellurite glasses. The main channels of energy transfer between Er3+/Ho3+ are analyzed in detail. The microscopic interaction parameters of resonant and non-resonant (phonon-assisted) energy transfer parameters via Er3+→Ho3+ are calculated. The result shows that the resonant energy transfers Er3+(2H11/2(4S3/2))→Ho3+(5F4(5S2)) and Er3+(4F9/2)→Ho3+(5F5) are very efficient and non-resonant energy transfers Er3+(4I13/2)→Ho3+(5I7) and Er3+(4I11/2)→Ho3+(5I6), which are a phonon-assisted energy transfer process because of energy mismatch are also existed and cannot be neglected. 相似文献
5.
Hongtao Sun Junjie Yang Junjie Zhang Zhonghong Jiang 《Solid State Communications》2005,133(12):753-757
Er3+-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 PbCl2 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 2H11/2→4I15/2, 4S3/2→4I15/2, and 4F9/2→4I15/2, respectively, were observed at room temperature. With increasing PbCl2 content, the intensity of green (525 and 546 nm) emissions increases significantly, while the red (657 nm) emission increases slowly. The results indicate that PbCl2 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. 相似文献
6.
Thermal stability, Raman spectra and blue upconversion luminescence properties of Tm3+/Yb3+-codoped halide modified tellurite glasses have been studied. The results showed that the mixed halide modified tellurite glass (TFCB) has the best thermal stability, the lowest phonon energies and the strongest upconversion emissions. The effect of halide on upconversion intensity is observed and discussed and possible upconversion mechanisms are evaluated. The intense blue upconversion luminescence of Tm3+ in TFCB glass may be a potentially useful material for developing upconversion optical devices. 相似文献
7.
Tm3+/Yb3+-codoped germanate-niobic (GN) and germanium-bismuth (GB) glasses have been synthesized by conventional melting and quenching method. Intense blue and weak red emissions centered at 477 and 650 nm, corresponding to the transitions 1G4→3H6 and 1G4→3H4, respectively, were observed at room temperature. The possible up-conversion mechanisms are discussed and estimated. GN glass showed a weaker up-conversion emission than GB glass, which is inconsistent with the prediction from the difference of maximum phonon energy between GN and GB glasses. In this paper, Raman spectroscopy was employed to investigate the origin of the difference in up-conversion luminescence in the two glasses. Compared with phonon side-band spectroscopy, Raman spectroscopy extracts more information including both phonon energy and phonon density. For the first time, our results reveal that, besides the maximum phonon energy, the phonon density of host glasses is also an important factor in determining the up-conversion efficiency. 相似文献
8.
Hongtao Sun Chunlei Yu Liyan Zhang Dongbin He Lili Hu 《Solid State Communications》2005,134(9):595-599
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 PbCl2 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 1G4→3H6 and 1G4→3H4, 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. 相似文献
9.
Feng Song Lin Han Hao Tan Jing Su Jia Yang Jian-guo Tian Guang-yin Zhang Zhen-xiang Cheng 《Optics Communications》2006,259(1):179-186
Using Czochralski (CZ) pulling method, an Er3+/Yb3+-codoped NaY(WO4)2 crystal was prepared. Absorption spectra, emission spectra and excitation spectra of this crystal were measured at room temperature. Some optical parameters, such as intensity parameters, spontaneous emission probabilities and lifetimes, were calculated from absorption spectra with Judd-Ofelt (J-O) theory. Upconversion luminescence excited by a 970 nm diode laser was studied. In this crystal, green upconversion luminescence is particularly intensive. Energy transfer mechanisms that play an important role in upconversion processes were analyzed. Two cross-relaxation processes: 4G11/2 + 4I9/2 → 2H11/2 (or 4S3/2) + 2H11/2 (or 4S3/2), and 4G11/2 + 4I15/2 → 2H11/2 (or 4S3/2) + 2I13/2, which contribute to the intensive green luminescence under 378 nm excitation, were put forward. Background energy transfer 4G11/2(Er3+) + 2F7/2(Yb3+) → 4F9/2(Er3+) + 2F5/2(Yb3+) was also demonstrated. 相似文献
10.
Energy transfer has been studied from Er3+ to Eu3+ ions on excitation with NIR photons (796 and 980 nm) with and without Yb3+ ions. It is found that in one case the presence of Yb3+ enhances the fluorescence yield (980 nm excitation) whereas in the other case it quenches (796 nm excitation). Energy transfer from Er3+ ion's levels 4S3/2 and 2H11/2 is verified by decay curve analysis in both the cases. The nature of interaction between the donor (Er) and the acceptor (Eu) ions is found to be dipole-dipole. The energy transfer parameters viz. transfer probability, critical distance etc. have been calculated. 相似文献
11.
制备了Tm3+/Yb3+共掺TeO2-PbO-ZnO-La2O3玻璃,研究了玻璃红外吸收光谱和980 nm激光抽运下上转换发光光谱,分析了上转换发光机制.基于Tm3+和Yb3+的能级图及上转换机制建立了速率方程,得出了稀土离子各能级的粒子数分布密度以及Tm3+与Yb3+之间的能量转移系数Cbi(i=0,1,3).结果表明,随着PbO加入,Yb3+:2F5/2与Tm3+:3H4间的能量转移不断增加,上转换蓝光的发光强度明显增强. 相似文献
12.
Hongtao Sun Zhongchao Duan Gang Zhou Junjie Zhang Zhonghong Jiang 《Solid State Communications》2005,135(3):174-178
Tm3+-doped oxide-chloride germanate and tellurite glasses have been synthesized by conventional melting method. Intense up-conversion luminescence emissions were simultaneously observed at room temperature in these glasses. The possible up-conversion mechanisms are discussed and estimated. However, in these Tm3+-doped glasses, tellurite glass showed weaker up-conversion emissions than germanate glass, which is inconsistent with the prediction from the difference of maximum phonon energy between tellurite and germanate glasses. In this paper, Raman spectroscopy was employed to investigate the origin of the difference in up-conversion luminescence in the two glasses. Our results confirm that, besides the maximum phonon energy, the phonon density of host glasses is also an important factor in determining the up-conversion efficiency. 相似文献
13.
The Tm3+/Er3+:NaGd(MoO4)2 crystal with dimensions of Φ22×30 mm3 was grown by Czochralski method. Polarized spectra and fluorescence lifetime for the 4I13/2(Er3+)→4I15/2(Er3+) transition at room temperature were investigated. Based on the Judd-Ofelt theory, the spontaneous transition probabilities, the fluorescent branching ratios and the radiative lifetimes were calculated. The fluorescence lifetime was measured to be 1.81 ms. The detailed excited-transition mechanism with 800 nm radiation is also discussed. 相似文献
14.
Yujin Chen 《Solid State Communications》2004,132(8):533-538
Yb3+-doped La2(WO4)3 single crystals were grown by the Czochralski technique. Absorption and fluorescence spectra of the crystal were recorded at the room temperature. The stimulated emission cross-sections of Yb3+ ions were calculated using the reciprocity method and Fuchtbauer-Ladenburg formula, respectively. The fluorescence decay curves of 2F5/2 manifold of Yb3+ ions were recorded at room temperature for both crystal and powder samples. The effect of radiation trapping on the spectroscopic properties is discussed. Comparison with other Yb3+-doped laser crystals is made. The results show that Yb3+:La2(WO4)3 crystal is a promising laser material. 相似文献
15.
P. Sourková P. Nemec V. Nazabal V. Moizan R. Moncorgé 《Journal of luminescence》2009,129(10):1148-1153
Electronic transitions of Pr3+ ions in Ga-Ge-Sb-Se glasses corresponding to emissions in the infrared region were studied by means of absorption and emission spectroscopies and fluorescence lifetimes measurements. Transition probabilities, radiative lifetimes, branching ratios, and quantum efficiencies of most of the emission transitions including the infrared ones occurring around 1.3, 1.7, and 2.4 μm were estimated based on a standard Judd-Ofelt analysis. 相似文献
16.
Yu Yang 《Optics Communications》2008,281(20):5218-5221
Laser dyes such as pyrromethene 567 (PM567), perylene red (P-red) and coumarin 540A (C540A) were doped into zirconia-organically modified silicate (ORMOSIL) materials prepared by low temperature sol-gel technique. Narrow line-width distributed feedback (DFB) laser actions were induced in the PM567 and/or P-red doped sol-gel planar waveguide. Tuning of the output wavelength was achieved by varying the period of the gain modulation generated by a nanosecond Nd:YAG laser at 532 nm. Compared with those of PM567 and P-red solely doped thin films, tuning range of C540A, PM567 and P-red co-doped sol-gel planar waveguide was greatly extended, from 564.5 nm to 635.1 nm. 相似文献
17.
In a three-components fluorophosphate glass system, the introduction of H3BO3 brings some valuable influence to the spectroscopic and thermal properties of the glasses. With H3BO3 increases from 2 to 20 mol%, Ω6, Sed4I13/2, FWHM, Tg and fluorescence lifetime change from 3.21×10−20 cm2, 1.77×10−20 cm2, 45 nm, 480 °C and 8.8 ms to 4.66×10−20 cm2, 2.11×10−20 cm2, 50 nm, 541 °C and 7.4 ms, respectively. σabs, σemi, FWHM×τf×σemi has a maximum when H3BO3 is 11 mol%. Tg and Tx−Tg increases with H3BO3 introduction. Results showed that in fluorophosphate glasses, proper amount of B2O3 can be used as a modifier to suppress upconversion and improve spectroscopic properties, broadband property and crystallization stability of the glasses while keeps the fluorescence lifetime relatively high. 相似文献
18.
Hongtao Sun Liyan Zhang Shilong Zhao Junjie Zhang Dongbing He Zhongchao Duan Lili Hu 《Solid State Communications》2005,133(6):357-361
Structural and infrared-to-visible upconversion fluorescence properties of Er3+/Yb3+-codoped oxychloride lead-germanium-bismuth glass have been studied. The Raman spectrum investigation indicates that PbCl2 plays an important role in the formation of glass network, and has an important influence on the upconversion luminescence owing to lower phonon energy. Intense green and red emissions centered at 525, 546, and 657 nm, corresponding to the transitions 2H11/2→4I15/2, 4S3/2→4I15/2, and 4F9/2→4I15/2, respectively, were observed at room temperature. The quadratic dependence of the 525, 546, and 657 nm emissions on excitation power indicates that a two-photon absorption process occurs under 975 nm excitation. 相似文献
19.
The ultraviolet upconversion luminescence of Tm3+ ions sensitized by Yb3+ ions in oxyfluoride glass when excited by a 975 nm diode laser was studied in this paper. One typical ultraviolet upconversion luminescence lines positioned at 362.3 nm was found. It can be attributed to the five-photon upconversion luminescence transition of 1D2 → 3H6. Several visible upconversion luminescence lines at 451.1 nm, (477.9 nm, 462.5 nm), 648.7 nm, (680.5 nm, 699.5 nm) and (777.5 nm, 800.7 nm) were found also, which results from the fluorescence transitions of five-photon 1D2 → 3F4, three-photon 1G4 → 3H6, three-photon 1G4 → 3F4, two-photon 3F3 → 3H6 and two-photon 3H4 → 3H6 of Tm3+ ion, respectively. The theoretical analysis suggests that the upconversion mechanism of the 362.3 nm 1D2 → 3H6 upconversion luminescence is the cross energy transfer of {3H4(Tm3+) → 3F4(Tm3+), 1G4(Tm3+) → 1D2(Tm3+)} and {1G4(Tm3+) → 3F4(Tm3+), 3H4(Tm3+) → 1D2(Tm3+)} between Tm3+ ions. In addition, the upconversion luminescence of 1G4 and 3H4 state results from the sequential energy transfer {2F5/2(Yb3+) → 2F7/2(Yb3+), 3H4(Tm3+) → 1G4(Tm3+)} and {2F5/2(Yb3+) → 2F7/2(Yb3+), 3F4(Tm3+) → 3F2(Tm3+)} from Yb3+ ions to Tm3+ions, respectively. 相似文献
20.
Various coumarin dyes are co-doped with perylene red (P-red) and pyrromethene 567 (PM567) into vinyltriethoxysilane-derived solid media, respectively. Energy transfer among laser dyes has been observed, and the effect of coumarin dye concentration on the laser properties has been investigated. With the presence of coumarin dye and pyrromethene 567, enhanced laser performances based on energy transfer of perylene red have been exhibited. The laser efficiency can be improved by two-fold and broad tunable range as wide as 80 nm can be achieved. At the pump intensity of 1.0 J/cm2, the laser output of co-doping perylene red decreases less than 30% after 30,000 pulses. 相似文献