共查询到20条相似文献,搜索用时 15 毫秒
1.
R. Rajaramakrishna Safakath Karuthedath R.V. Anavekar H. Jain 《Journal of Non》2012,358(14):1667-1672
Synthesis, characterization and optical nonlinearity of lead lanthanum borate glass embedded with gold nanoparticles have been investigated. DSC thermogram shows characteristics glass transition temperature at Tg = 775 K. Glasses doped with Au were subjected to heat treatment at 823 K with different annealing time and then, slowly cooled to room temperature show striking ruby color. SAED and TEM analyses have confirmed that f.c.c. Au nanoparticles of ~ 40 nm size are present in these glasses. An absorption peak centered on 563 nm has been observed in heat treated samples, which is attributed to surface plasmon resonance of gold nanoparticles. Nonlinear optical studies with open aperture Z-Scan technique show saturable absorption for heat treated samples at low intensity and reverse saturable absorption in samples without heat treatment at high intensity. 相似文献
2.
Rong Yang Mengfei Mao Yang Zhang Yixi Zhuang Ke. Zhang Jianrong Qiu 《Journal of Non》2011,357(11-13):2396-2399
Bi–Er–Tm co-doped germanate glasses and Bi, Er, Tm singly doped glasses were prepared and characterized through absorption spectra, NIR emission spectra and decay lifetime. A super broadband near-infrared emission from 1000 nm to 1600 nm, covering the whole O, E, S, C, and L bands, was observed in the Bi–Er–Tm co-doped samples due to the result of the overlapping of the Bi related emission band (centered at 1300 nm), the emission from Er3+ 4I13/2 → 4I15/2 transition (centered at 1534 nm) as well as the emission from Tm3+ 3H4 → 3F4 transition (centered at 1440 nm), which is essential for broadly tunable laser sources and broadband optical amplifiers. The energy transfer process was also discussed at the end of the paper. 相似文献
3.
Enhanced mid-IR luminescence of Tm3+ ions in Ga2S3 nanocrystals embedded chalcohalide glass ceramics
Shixun Dai Changgui Lin Feifei Chen Xianghua Zhang Chao Liu Kai Xu Jong Heo Xiang Shen Xunsi Wang 《Journal of Non》2011,357(11-13):2302-2305
Chalcohalide glass with a composition of 65GeS2–25Ga2S3–10CsI (in mol%) doped with 0.6 wt% Tm3+ ions was prepared by conventional melt–quench method. By heat treating the precursor glass at 20 °C above its glass transition temperature Tg for different durations, IR transparent glass ceramics were obtained. X-ray diffraction (XRD) and scanning electron microscope (SEM) showed that Ga2S3 crystallites were precipitated after heat treatment and their grain sizes were in nano-scale and increased with the elongation of heat treated time. Mid-IR luminescence properties of the glass and transparent glass ceramic samples were investigated. The emissions at 2.3 and 3.8 μm corresponding to optical transitions of 3H4 → 3H5 and 3H5 → 3F4 of Tm3+ ions were significantly enhanced by the presence of Ga2S3 nanocrystals and reached a maximum after 8 hours treatment. 相似文献
4.
Nengli Dai Huaixun Luan Bing Xu Lvyun Yang Yubang Sheng Zijun Liu Jinyan Li 《Journal of Non》2012,358(2):261-264
We have studied the effects of Si doping on the near infrared (NIR) luminescence observed in low Bi doped ( 0.1 mol% ) glasses and the energy transfer from Yb3+ to Bi. The broadband near infrared can only be observed when Si is introduced in the Bi-doped glass. The origin of this fluorescence can be attributed to Bi ions at low valence. Efficient energy transfer from Yb3+ to Bi NIR active ions is achieved by co-doping of Si. There is an increment of about ~ 29 times of the emission intensity from Bi-related active center as the Yb3+ concentration varies from 0 to 2.0 mol% and the amount of Si is 0.05 mol% under 980 nm excitation. The possible mechanism of energy transfer from Yb3+ to Bi is also discussed. 相似文献
5.
M. Reza Dousti M.R. Sahar S.K. Ghoshal Raja J. Amjad R. Arifin 《Journal of Non》2012,358(22):2939-2942
The melt quenching method was used to synthesize the Ag0 nanoparticles and Er3 + ions co-doped zinc tellurite glass. The glasses were characterized by differential thermal analyzer, UV–VIS-IR absorption, photoluminescence spectroscopy and TEM imaging. Heat treatment at different annealing time intervals above the glass transition temperature was applied to reduce the Ag+ ions to Ag0 NPs. The influence of heat treatment on structural and optical properties is examined. Intense and broad up-conversion emissions of silver are recorded in the visible region. Up-conversion luminescence spectra revealed three major emission peaks at 520, 550 and 650 nm originating from 2H11/2, 4S3/2 and 4F9/2 levels, respectively. An efficient enhancement in visible region is observed for samples containing silver NPs. The absorption plasmon peaks are evidenced around 560 and 594 nm. The effect of localized surface plasmon resonance and the energy transfer from the surface of silver NP to trivalent erbium ions are described as the sources of enhancement. 相似文献
6.
《Journal of Non》2006,352(38-39):4062-4068
Glasses with the base composition 16Na2O · 10CaO · 74SiO2 doped with copper and iron or copper and manganese were studied by high temperature UV–vis–NIR spectroscopy. The spectra exhibited distinct absorption bands attributed to the respective transition metal ions present (Cu2+, Fe2+, Fe3+, Mn3+). In glasses doped with only one polyvalent element, the absorption decreases linearly with increasing temperature, the absorption bands are shifted to smaller wave numbers and get broader. In glasses doped with two types of transition metals, the situation is the same up to a temperature of around 550 °C. At larger temperature, the Cu2+-absorption in glasses also co-doped with iron increases again, while in glasses doped with both copper and manganese the absorption is approximately the same as in glasses solely doped with copper. It is shown that this is due to redox reactions between polyvalent species. These reactions are frozen in at temperatures <550 °C. 相似文献
7.
Tb3+ doped X-ray conversion glassy screen with an industrial scale (50 mm × 50 mm × 12 mm) was successfully fabricated, and its luminescent properties and applications in CCD imaging system were investigated. Results showed that Tb3+ doped silicate glasses mainly emit weak blue (400–460 nm) and strong green (480–570 nm) fluorescence. With the increase of Tb3+ ion concentration, the intensity of green emission increases, but that of blue emission decreases. Gd3+ ions can sensitize the luminescence of Tb3+ ions among silicate glasses. With the increase of CeO2 concentration, the luminescent intensity of Tb3+ doped silicate glasses at 550 nm quickly decreases. However, the irradiation resistance of Tb3+ doped silicate glasses can be effectively improved by CeO2 addition. The imaging quality of the luminescent glass screen is more excellent than that of Gd2O2S polycrystalline screens. 相似文献
8.
Tb3 + and Yb3 + co-doped oxyfluoride glasses were fabricated in a lithium–lanthanum–aluminosilicate matrix (LLAS) by a melt-quench technique. Glass-ceramics were obtained by appropriate heat treatment of the as-prepared glasses. Visible to near-infrared down-conversion luminescence was studied for glass and glass-ceramic samples with different Yb3 + concentrations. It has been found that the luminescence intensity at 940–1020 nm from Yb3 + ions increases while the emission lifetime of Tb3 + ions decreases in the glass-ceramic compared to that in the as-prepared glass, which indicates that the energy transfer efficiency increases in the glass-ceramics compared to that in the as-prepared glass. The down-conversion luminescence also increased for increasing Yb3 + concentration from 1 mol% to 2 mol%, but decreased for the sample with a high Yb3 + co-doping concentration of 8 mol%, which is attributed to the concentration quenching. 相似文献
9.
《Journal of Non》2005,351(49-51):3699-3703
Thermally stimulated luminescence (TSL) properties of cerium and terbium doped SiO2 sol–gel glasses were studied after X-ray irradiation in the temperature range 10–700 K. The role of Ce3+ and Tb3+ as recombination centers was shown. The existence of a distribution of trap levels was observed; the activation energies of such a distribution were calculated to extend from about 8 × 10−3 eV up to 1.8 eV for both cerium and terbium doped sol–gel glasses. The effect of a post-densification thermal treatment on TSL properties was also analyzed. 相似文献
10.
《Journal of Non》2005,351(6-7):523-529
Glasses doped either with chromium or manganese or with both chromium and manganese were melted from the raw materials and studied by UV–vis–NIR spectroscopy. The measurements were carried out at temperatures in the range from 25 to 800 °C. In the glasses doped with only one transition metal oxide, the intensity of the absorption lines decreases and the full width at half maximum increases with increasing temperatures. Simultaneously, the peaks were shifted to larger wave numbers. In glasses doped with both chromium and manganese, the same behaviour was observed up to a temperature of 600 °C. At larger temperatures, the absorption band at 27 500 cm−1 due to Cr6+ increases again, while the absorption band at 20 300 cm−1 caused by Mn3+ decreases more strongly than in glasses solely doped with manganese. The behaviour observed was explained by the redox reaction Cr6+ + 3Mn2+ ⇄ Cr3+ + 3Mn3+ which is shifted to the left while increasing the temperature. 相似文献
11.
Various fluoride, phosphate and borosilicate glasses with known properties and global structure have been doped with Dy3+ (4f9) and Sm3+ (4f5) between 1018 and 1021 cm?3 and their time resolved fluorescence in the visible range in combination with characteristic physical properties were studied. Different fit procedures were carried out. Although both ions differ in their intrinsic fluorescence lifetime, with 1.5 ms for Dy3+ and 6.5 ms for Sm3+, their dependence on glass matrix is remarkable similar. Fluoroaluminate glasses with varying phosphate content between 0 and 20 mol% (FPx), a pure phosphate glass (P100), and two borosilicate glasses with low (DURAN®-like) and high optical basicity (NBS1) were used for investigations. A strongly ionic surrounding by fluorine ligands, as in fluoroaluminate glass samples, provides the longest fluorescence lifetime. It decreases with increasing phosphate content by increasing oxygen surrounding and with increasing RE3+ doping. Large differences were detected in the two borosilicate glasses depending on their optical basicity mainly due to differences in the Na2O/B2O3 ratio. Duran-like samples with low Na2O content have shown phase separation with higher doping concentration. The RE3+ ions are accumulated in the borate-rich droplets. Surprisingly only very low concentration-quenching effects were observed. In the opposite of NBS1 samples with high Na2O content this generated extremely high quenching effect. 相似文献
12.
V.N. Rai B.N. Raja Sekhar P. Tiwari R.J. Kshirsagar S.K. Deb 《Journal of Non》2011,357(22-23):3757-3764
Ultra violet-visible (UV-Vis) and Fourier transform infrared (FT-IR) spectra of Nd doped phosphate glasses have been studied before and after gamma irradiation in order to understand the changes in the optical properties of glasses as well as to find the characteristics frequencies of the vibrational modes of chemical bonds, which decide the structural and spectral changes. UV, Vis, IR absorption and photoluminescence spectra of these glasses show changes depending on the composition of glass matrix. These changes are correlated on the basis of oxygen (O) and neodymium (Nd) concentration ratio obtained from energy dispersive X-ray spectroscopic (EDX) measurement. Gamma irradiation shows decrease in transmission below 700 nm for all the Nd3+ absorption lines from all the samples. Differential absorption spectra (UV-vis) of the samples before and after gamma irradiation show generation of some new bands below 700 nm along with dips (decrease) in the spectrum at the location of main Nd3+ absorption lines. This is attributed to the generation of different types of defects in the glass matrix along with possibility of change in the valence state of Nd3+ to Nd2+. IR absorption spectra of these glasses are found dominated mainly by the characteristics phosphate groups and water (OH) present in the glass network. The effects of gamma irradiation on IR absorption are observed in the form of bond breaking and possible re-arrangement of bonding. EDX and X-ray photoelectron spectroscopic (XPS) measurements indicate decrease in the relative concentration of oxygen in the glass samples after γ-irradiation. 相似文献
13.
N.G.C. Astrath A.N. Medina A.C. Bento C. Jacinto T. Catunda S.M. Lima L.M. da Silva F.G. Gandra M.L. Baesso 《Journal of Non》2008,354(2-9):574-579
In this work, the thermal lens spectrometry was applied to measure the thermo-optical properties of Nd2O3-doped low silica calcium aluminosilicate glasses as a function of temperature, between 4.3 and 300 K. The thermal relaxation calorimetry was used to determine the specific heat, cp. The results showed a decrease of the thermal diffusivity of about one order of magnitude from 4.3 K up to 300 K, with a T?1 dependence in the interval between 20 and 70 K and a T?0.35 between 4.3 and 20 K. The fluorescence quantum efficiencies of the doped samples were calculated down to 50 K, showing a variation of the order of 12% and 25% for the samples with 0.6 and 1.04 mol% of Nd2O3, respectively. In addition, the temperature corresponding to the maximum in cp/T3, the so-called boson peak, was observed at about 17 K for the undoped sample and at lower temperatures for the doped glasses. In conclusion, our results showed the ability of the time resolved thermal lens to determine the thermo-optical properties of glasses at temperatures lower than 300 K, bringing new possibilities for experiments in a wide range of optical materials. 相似文献
14.
15.
《Journal of Non》2006,352(32-35):3647-3652
The aim of this paper is to present a study of the thermal lens technique in quantifying the thermo optical coefficients: ds/dT (optical path change with temperature), thermal diffusivity and conductivity of PbO–Bi2O3–Ga2O3–BaO glasses doped with Yb3+. The thermal lens results indicate that the heat generation, as a function of the incident wavelength, resembles the absorption band 2F7/2 → 2F5/2 of Yb3+. Thermal diffusivity of 2 × 10−3 cm2/s and thermal conductivity of 4.5 × 10−3 W/K cm were obtained and are similar to other glasses already reported in previous literature. The results emphasize that the thermal lens technique can be a powerful tool to study the heat generation of new glassy systems. 相似文献
16.
《Journal of Non》2007,353(5-7):506-509
We report on fabrication of Er3+-activated LaF3 nanocrystals in transparent glasses using an original technique, which combines both heat treatment, below glass crystallization temperature, and ultraviolet laser irradiation at 244 nm. The main advantage of this method is to control the spatial localization of the nanoparticles in the glass sample, whereas annealing solely at the crystallization temperature leads to a fully crystallized glass sample. Thermal differential analysis was used to determine the crystallization temperature of the sample. The photoluminescence spectra behaviour of Er3+ ions, collected from the UV-irradiated and unirradiated regions, allowed us to follow and to distinguish the structural changes in the glass network under heat treatment and ultraviolet exposure. 相似文献
17.
Weidong Xiang Haijun Zhao Jiasong Zhong Yuqing Guo Zhaoping Chen Hongyan Luo Xiuli Zhao Xiaojuan Liang Xinqi Yang 《Journal of Non》2012,358(18-19):2641-2649
The sodium borosilicate glass doped with Cu7.2S4 quantum dots was prepared by using both sol–gel and atmosphere control methods. The formation mechanism and the microstructure of the glass were examined using differential thermal analysis and thermal gravimeter (TG-DTA), X-ray powder diffraction (XRD), X-ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM), scanning transmission electron microscopy (STEM), energy dispersive X-ray spectra (EDX), high-resolution transmission electron microscopy (HRTEM), and selected area electron diffraction (SAED). The results revealed that Cu7.2S4 quantum dots in orthorhombic crystal system had formed in the glass, and the size ranged from 9 nm to 21 nm. In addition, Z-scan technique was used to measure the third-order optical nonlinearities of the glass. The results indicated that the third-order optical nonlinear refractive index γ, the absorption coefficient β, and the susceptibility χ(3) of the glass were 1.11 × 10? 15 m2/W, 8.91 × 10? 9 m/W, and 6.91 × 10? 10 esu, respectively. 相似文献
18.
Jianrong Qiu Mingying Peng Jinjun Ren Xiangeng Meng Xiongwei Jiang Congshan Zhu 《Journal of Non》2008,354(12-13):1235-1239
Broadband infrared luminescence is observed in various Bi-doped oxide glasses prepared by conventional melting-quenching technique. The absorption spectrum of the Bi-doped germanium oxide glass consists of five broad peaks at below 370, 500, 700, 800 and 1000 nm. The fluorescence spectrum exhibits a broad peak at about 1300 nm with full width at half maximum (FWHM) of more than 300 nm when excited by an 808 nm laser diode. The fluorescence lifetime at room temperature decreases with increasing Bi2O3 concentration. Influence of the glass composition and melting atmosphere on the fluorescence lifetime and luminescent intensity is investigated. The mechanism of the broadband infrared luminescence is suggested. The product of stimulated emission cross-section and lifetime of the Bi-doped aluminophosphate glass is about 5.0 × 10?24 cm2 s. The glasses might be promising for applications in broadband optical fiber amplifiers and tunable lasers. 相似文献
19.
In searching for new kind of photoelectric material, chalcogenide glasses in the GeS2–Sb2S3–CdS system have been studied and their glass-forming region was determined. The system has a relatively large glass-forming region that is mainly situated along the GeS2–Sb2S3 binary side. Thermal, optical and mechanical properties of the glasses were reported and the effects of compositional change on their properties are discussed. These novel chalcogenide glasses have relatively high glass transition temperatures (Tg ranges from 566 to 583 K), good thermal stabilities (the maximum of deference between the onset crystallization temperature, Tc, and Tg is 105 K), broad transmission region (0.57–12 μm) and large densities (d ranges from 2.99 to 3.34 g cm?3). These glasses would be expected to be used in the field of rare earth doped fiber amplifiers and nonlinear optical devices. 相似文献
20.
《Journal of Non》2006,352(6-7):534-538
Copper ruby glasses are commonly produced by dissolving copper in glass (also containing a reducing agent) under relatively reducing conditions to stabilize Cu+, followed by a heat treatment to generate the characteristic red color attributed to a colloidal dispersion of Cu0 particulates. This study produced copper ruby glasses in a one-step synthesis; 0.1–0.2 wt% copper was included in an alkali borosilicate glass that was synthesized at a very reducing atmosphere. The classic red coloration was directly generated by the colloidal dispersion of elemental copper nanoparticles, (Cu0)n, that formed without further heat treatment. Addition of europium to the copper-containing glass melts led to dramatic spectral changes, with the europium addition not only affecting the amount of elemental copper but also the size of these copper particulates. The net result was the production of a dichroic glass that was ruby red in reflected light and blue in transmitted light. This dichroism was stable only over a certain range of copper nanoparticle sizes, unique to particular Cu/Eu ratios in the glass and optimized at 1150 °C in the alkali borosilicate composition. 相似文献