共查询到20条相似文献,搜索用时 15 毫秒
1.
L.X. Yi M. Wang S.Y. Feng Y.K. Chen G.N. Wang L.L. Hu J.J. Zhang 《Optical Materials》2009,31(11):1586-1590
Emission properties of Ho3+ at 2.0 μm and the energy transfer mechanism between Yb3+, Er3+ and Ho3+ ions in fluorophosphate glasses are investigated. The measured emission spectra show that the 5I7 → 5I8 transition of Ho3+ upon 980 nm laser diode excitation is strong. Judd–Ofelt intensity parameters (Ωλ, λ = 2, 4, 6), spontaneous transition probability (Arad), radiative lifetime (τr), absorption cross section (σa), stimulated emission cross section (σe) and FWHM × for the transition of Ho3+: 5I7 → 5I8 are calculated and discussed. The obtained results show that the present Yb3+/Er3+/Ho3+ triply-doped fluorophosphate glass can be identified to be a promising material at 2.0 μm emission. 相似文献
2.
A.N. Moiseev V.V. Dorofeev A.V. Chilyasov I.A. Kraev M.F. Churbanov T.V. Kotereva V.G. Pimenov G.E. Snopatin A.A. Pushkin V.V. Gerasimenko A.F. Kosolapov V.G. Plotnichenko E.M. Dianov 《Optical Materials》2011,33(12):1858-1861
High-purity TeO2–ZnO–Na2O–Bi2O3 and TeO2–WO3–La2O3–MoO3 glasses were produced by melting the high-purity oxides mixtures in platinum or gold crucible at 800 °C in hermetic chamber in the purified oxygen atmosphere. The content of limiting impurities in the produced initial oxides and glasses, the optical properties as well as the stability to crystallization were investigated. The optical fibers were produced from high-purity tellurite glasses with losses at the level of several hundreds of dB/km.The total content of 3d-transition metals in the glasses was not more than 1 ppm wt and content of hydroxyl groups corresponded to the absorption level of 0.001–0.002 cm−1 at ∼3 μm. The absorption band, monotonically increasing with the increase in MoO3 content, was observed in dry TeO2–WO3–La2O3–MoO3 glasses with the maximum at about 3.7 μm. 相似文献
3.
Luciana Reyes Pires Kassab Mauricio Eiji Camilo Carlos Taveira Amâncio Davinson Mariano da Silva Jose Roberto Martinelli 《Optical Materials》2011,33(12):1948-1951
In the present work it is reported for the first time the effects of gold nanoparticles in the infrared-to-visible frequency upconversion of Er3+–Yb3+ co-doped TeO2–PbO–GeO2 glasses. Intense emission bands at 527, 550, and 660 nm were observed corresponding to the Er3+ transitions. It is shown that the combined effects of gold nanoparticles and the efficient Yb3+ → Er+3 energy transfer mechanism change the upconversion visible spectrum. It is then demonstrated that the enhanced local field contribution due to gold nanoparticles and the energy transfer processes between two different rare-earth ions can be used to control and improve the efficiency of luminescent glasses. 相似文献
4.
Yanmin Yang Zhiping Yang Panlai Li Xu Li Qinglin Guo Baojiu Chen 《Optical Materials》2009,32(1):133-138
Transparent and uniform tellurite–phosphate glasses were prepared and the reason why the substitution of NaPO3 for P2O5 can eliminate the coloration of tellurite–phosphate was discussed. The result of TDA indicated that introducing NaPO3 into tellurite glasses can improve thermal stability of glass hosts. The compositional dependence of absorption cross-sections of 4I13/2, 4I11/2 and 2H11/2 level, emission cross-section of 4I13/2 level, host phonon energy, up-conversion and 1.5 μm optical emission intensity as well as and quantum yield for 4I13/2 level in PTEr glasses were investigated too. By analyzing obtained data, authors believe that tellurite–phosphate glasses can be used as potential host material for developing optical amplifiers. 相似文献
5.
We report measurements of the energy transfer between Er3+ and Ce3+ in Y2O3. The transition between the Er3+ 4I11/2 and 4I13/2 excited states can be stimulated by energy transfer to Ce3+, augmenting the population in the 4I13/2 state at the expense of that in the 4I11/2 state. Experiments were performed on Y2O3 planar waveguides doped with 0.2 at.% erbium and 0–0.42 at.% cerium by ion implantation. From measurements of Er3+ decay rates as a function of cerium concentration we derive an energy transfer rate constant of 1.3×10−18 cm3/s. The efficiency of the energy transfer amounts to 0.47 at 0.42 at.% cerium. The energy transfer rate constant measured in Y2O3 is two times smaller for Er3+→Ce3+ than that for Er3+→Eu3+ in the same material. 相似文献
6.
In the present work, tellurite 20Li2O–80TeO2 glasses were prepared with identical nominal composition under different glass-forming histories to produce a stressed and stress-free samples. X-ray Diffraction (XRD) and Differential Scanning Calorimetry (DSC) techniques were used to study the effects of the glass-forming histories on the thermal and structural properties of these glasses. The γ-TeO2 (metastable), α-TeO2 and α-Li2Te2O5 phases were identified during the controlled devitrification in these glasses. The mestastable character of the γ-TeO2 phase was clearly observed in the glass under stress but this effect is not so clear in the stress-free glass. The γ-TeO2 and α-TeO2 phases crystallizes during the initial stages of crystallization in both studied glasses while the α-Li2Te2O5 phase crystallize in the final stages of the crystallization. The activation energies and Avrami exponent were calculated for both studied glasses with different particle size leading to E3 > E2 > E1 for stressed glass and E3 > E2 ≈ E1 for stress-free glass, where E1, E2 and E3 were associated to the γ-TeO2, α-TeO2 and α-Li2Te2O5 phases, respectively. The observed distinct in both glasses is an indicative that nucleation and growth takes place by more than one mechanism in the early stages of the crystallization. 相似文献
7.
A range of coloured electronic or mixed ionic–electronic glasses has been evidenced in the Na2O–MoO3–P2O5 system. The properties of these glasses have been studied along different composition lines corresponding either to a fixed Na2O content or a constant Mo/P ratio. An EPR spectroscopy investigation of these glasses has allowed to determine the Mo5+ ion percentages in these materials. The electrical properties of these glasses have been studied by impedance spectroscopy, and the electronic and ionic contributions have been evaluated. The properties of these sodium glasses have been compared with those of lithium glasses with the same compositions. 相似文献
8.
Phosphate glasses in the compositions of 70P2O5–15Al2O3–14Na2O–1RE3+ (RE = Sm, Dy, and Tm) (mol%) were prepared by melt-quenching technique and characterized optically. The differential thermal analysis (DTA) profile of the host glass was carried out to confirm its thermal stability. For all the glasses absorption, photoluminescence and decay measurements have also been carried out. These glasses have shown strong emission and absorption bands in visible and near-infrared (NIR) region. From the measured absorption spectra, Judd–Ofelt (J–O) intensity parameters (Ω2, Ω4 and Ω6) have been calculated for all the studied ions. For Sm3+ doped glass, four emission bands centered at 562 nm (4G5/2 → 6H5/2), 598 nm (4G5/2 → 6H7/2), 644 nm (4G5/2 → 6H9/2), and 704 nm (4G5/2 → 6H11/2) have been observed with 402 nm (6H5/2 → 4F7/2) excitation wavelength. Of them, 598 nm (4G5/2 → 6H7/2) has shown a bright orange emission. With regard to Dy3+ doped glass, a blue emission band centered at 486 nm (4F9/2 → 6H15/2) and a bright yellow emission at 575 nm (4F9/2 → 6H13/2) have been observed, apart from 662 nm (4F9/2 → 6H11/2) emission transition with an excitation at 388 nm (6H15/2 → 4I13/2,4F7/2) wavelength. Emission bands of 650 nm (1G4 → 3F4) and 785 nm (1G4 → 3H5) transitions for the Tm3+ doped glass, with an excitation wavelength at 466 nm (3H6 → 1G4), have also been observed. The stimulated emission cross-sections of all the emission bands of RE3+ glasses (RE = Sm, Dy, and Tm) have been computed based on their measured full-width at half maximum (FWHM, Δλ) and measured lifetimes (τm). 相似文献
9.
Xiaolin Zheng Haizheng Tao Changgui Lin Shaoxuan Gu Guoping Dong Xiujian Zhao 《Optical Materials》2009,31(10):1434
The infrared transmitting surface crystallized chalcohalide glasses containing nontoxic and excellent nonlinear optical AgGaGeS4 crystallites were fabricated by heat-treatment of the as-prepared 30GeS2 · 35Ga2S3 · 35AgCl chalcohalide glass at 350 °C (Tg −10 °C) for 24 h. An intensive second harmonic generation (SHG) was observed clearly using the Maker fringe technique, and the origin of SHG was mainly ascribed to the AgGaGeS4 nonlinear optical crystallites contained in the surface crystallized layer. The thickness of the surface crystallized layer showing SHG activation is approximate 50 μm. The χ(2) susceptibility of the prepared surface crystallized 30GeS2 · 35Ga2S3 · 35AgCl chalcohalide glass is calculated to be about 12.4 pm/V at a fundamental wavelength of 1064 nm, which indicates a promising nonlinear optical material in the infrared spectral region. 相似文献
10.
D. Kahler N.B. SinghD.J. Knuteson B. WagnerA. Berghmans S. McLaughlinM. King K. SchwartzD. Suhre M. Gotlieb 《Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment》2011,652(1):183-185
In this paper we report on the electrical characteristics of three novel ternary compounds, Tl3AsSe3 (TAS), TlGaSe2 (TGS), and Tl4HgI6 (THI), pertaining to their use as radiation detectors. The details for growth and material characterization are not presented. A semiconductor based gamma ray detector requires a material with high Z, high density, high resistivity, appropriate bandgap (1.5-2 eV), low energy/electron-hole pair, and a high μτ product. CZT is currently the best semiconductor material for room temperature gamma ray spectroscopy; however, it is extremely difficult to produce large volumes of detector grade material, making it expensive and in limited supply. DNDO/DHS began searching for other materials that might perform as well as CZT but be easier to grow and in the end lower the cost. For this purpose, we investigated the above three materials as possible replacements for CZT as gamma ray detectors. The bulk resistivity, I-V curves, X-ray response, and gamma ray response measurements for doped and undoped crystals are presented and discussed. TAS shows good X-ray and gamma ray response, but has poor resistivity, which results in large dark current and poor spectral response. TGS has good resistivity, but shows poor X-ray and gamma ray response. THI has excellent resistivity, shows some X-ray and gamma ray response, and has great potential as a gamma ray detector. 相似文献
11.
Nobuko MaedaNoriyuki Wada Hiroaki OnodaAkira Maegawa Kazuo Kojima 《Thin solid films》2003,445(2):382-386
Films of (x/2)Er2O3-100ZrO2 (x=0, 0.1, 1 and 5) were prepared by the sol-gel and dip-coating methods, and the influences of the type of ZrO2 phase on Er3+ spectroscopic properties were investigated. X-ray diffraction patterns show the existence of metastable tetragonal phase at low temperatures, which are probably caused by both the excess surface energy due to the small crystallite-size effect (J. Phys. Chem. 4 (1965) 1238) and the stabilization of ZrO2 with the addition of Er2O3 (J. Phys. Chem. B 106 (2002) 1909; J. Ceram. Soc. Jpn. 107 (1999) 1111). Under excitation at 488 nm, the green (525+545 nm) downconversion fluorescence due to the (2H11/2+4S3/2)→4I15/2 transition and the red (670 nm) downconversion fluorescence due to the 4F9/2→4I15/2 transition were observed, and their intensities increased with increasing the heat-treatment temperature regardless of the type of the ZrO2 phase. On the other hand, the intensity of red upconversion fluorescence also increased monotonically with the heat-treatment temperature under excitation at 780 nm, while the green upconversion fluorescence was hardly observed in the tetragonal phase (for the film with x=1, below 800 °C; x=5, below 700 °C), but was observed in the cubic (x=1, at 800 °C or above; x=5, at 700 °C or above) and monoclinic (x=0.1, at 600 °C or above) phases under excitations at 647 and 780 nm. The reason is probably that the f-f transition probability concerning the 4I13/2, from which the excited state absorption occurs, varied sensitively with the local structure of Er3+ ions in the different phase of ZrO2. 相似文献
12.
Bo Wang Lihong Cheng Haiyang Zhong Jiashi Sun Yue Tian Xiangqing Zhang Baojiu Chen 《Optical Materials》2009,31(11):1658-1662
Optical transition intensity parameters of Er3+ in ZBLAN were carefully calculated, and the obtained results were compared with those reported by others. The emission cross sections of 4S3/2 → 4I13/2 and 4I11/2 → 4I13/2 transitions were confirmed according to the Fuchtbauer–Ladenburg (FL) formula. The excited state absorption cross sections for 4I13/2 → 4S3/2 and 4I13/2 → 4I11/2 transitions were derived by using the reciprocity relationship in the framework of McCumber theory. The laser gain properties of 4S3/2 → 4I13/2 and 4I11/2 → 4I13/2 transitions were discussed. 相似文献
13.
Optical constants of vacuum-evaporated thin films in the Ge1 − xSe2Pbx (x = 0, 0.2, 0.4, 0.6) system were calculated from reflectance and transmittance spectra. It is found that the films exhibit a non-direct gap, which decreases with increasing Pb content. The variation in the refractive index and the imaginary part of the dielectric constant with photon energy is reported. The relationship between the optical gap and chemical composition in chalcogenide glasses is discussed in terms of the average heat of atomization. 相似文献
14.
Chyuan Haur Kao Chun Chi ChenChing Hua Huang Chuan Yu HuangChih Ju Lin Jiun Cheng Ou 《Thin solid films》2012,520(10):3857-3861
In this study, Ti-doped gadolinium oxide (Gd2TiO5) is investigated by X-ray diffraction, atomic force microscopy, and capacitance voltage curves (C-V) as the charge trapping layer in metal-oxide-high-k material-oxide-silicon structure memories. It was found that the Gd2TiO5 charge-trapping layer with an HfO2 blocking layer annealed at 900 °C had a larger window of 4.8 V in the C-V hysteresis loop, a faster program/erase speed and good retention without significant drift up to 104 cycles. This excellent performance was attributed to the well-crystallized Gd2TiO5 structure and the higher probability of charges being trapped in the deep trap energy level of the Gd2TiO5. This Gd2TiO5 memory device with post-annealing shows considerable promise for use in future flash memory applications. 相似文献
15.
In this paper, the aluminum borate whisker (ABOw) and BaPbO3 particles (BPOp)/Al hybrid composite with radiation protection function was fabricated by squeeze casting technique. The microstructure and properties of the hybrid composite were investigated. The test results show that BPOp and aluminum matrix have a reaction, and this reaction forms a coating on the surface of ABOw. The introduction of BPOp increases radiation protection function of the matrix evidently, at the same time, the hybrid composite has better mechanical properties compared with the aluminum matrix and ABOw/Al composite. 相似文献
16.
Morgan Cason Danilo Bersani Gianni Antonioli Pier Paolo Lottici Angelo Montenero Michela Cavalli 《Optical Materials》1999,12(4):447-452
The build-up time of the thermal lens effect induced by a Gaussian beam in the DO3-doped sol–gel system xTiO2 · (100 − x)SiO2 at different compositions, both in the liquid and gel phases has been measured in a Z-scan geometry. While the pure titania samples show a minimum of the thermal diffusivity, a maximum is found for x ≈ 30. The sol to gel transformation leads to an increase of the build-up times at all compositions. 相似文献
17.
In this paper, we report silica based planar waveguides doped with Er3+, and co-doped with GeO2 and Al2O3. These sol–gel derived planar waveguides were fabricated on SOS (silica on silicon) using multiple spin-coating and rapid thermal processing (RTP). Investigation has been made on their characteristics in terms of their application in optical amplification and lasing, including photoluminescence (PL), fluorescence lifetime, refractive index, propagation loss, surface roughness, Fourier transform infrared (FTIR) spectrum and X-ray diffraction (XRD) analysis. The propagation loss of a 20-layer planar waveguide was measured to be about 1.6 dB/cm for TE0 and 2.2 dB/cm for TM0 mode. A strong emission transition (4I13/2→4I15/2) at 1.536 μm with a lifetime of 3.6 ms has been obtained for an optimized molar composition of 90SiO2: 10GeO2: 20AlO1.5: 1ErO1.5. 相似文献
18.
Differential scanning calorimetry (DSC) was used in this work to study the effect of La2O3 addition on crystallization mechanism of barium-lead-zinc phosphate glasses. Bulk glasses from two different routes (using P2O5 and H3PO4 as starting materials) presented only one crystallization peak. An assessment of glass-forming ability (GFA) was performed from recent theory that is connected to glass stability (GS), and is also correlated to critical cooling rate, qcr. Systems with high La2O3 content presented some of the highest GS values and estimated critical cooling rates (qcr) lower than 0.079 K/s. For both routes were determined the activation enthalpies for crystallization, that were 126 ± 12 kJ/mol (for P2O5) and 110 ± 32 kJ/mol (for H3PO4). The calculated Avrami n parameters, based on exothermic crystallization peaks, were 3.50 ± 0.33 (for P2O5) and 3.09 ± 0.91 (for H3PO4), considering data from the lowest heating rate (5 K/min). These values suggest that the DSC peaks should be associated to volume crystallization, due to La2O3 influence, and crystallization did not change significantly using different routes. 相似文献
19.
R. Knizikevi?ius 《Vacuum》2012,86(12):1964-1968
The plasma chemical etching (PCE) of Si in CF4 + O2 plasma is considered. The concentrations of plasma components are calculated using values extrapolated from experimental data. Resulting calculations of plasma components are used for the calculation of Si etching rates. The concentrations of the adsorbed layer and surface components, obtained from analysis of PCE of silicon, are used for the comparison of site-balance and adsorbed-layer models. It is found that adsorbed-layer model predicts higher concentration of SiO2 molecules on the surface than site-balance model. The difference in SiO2 concentration is important during ion-beam-assisted etching and reactive ion etching processes as the models predict different etching rates due to different sputtering yields of Si atoms and SiO2 molecules. 相似文献
20.
Optical absorption and transmittance spectra of 60B2O3-(40-x)PbO-xMCl2 and 50B2O3-(50-x) PbO-xMCl2 (M = Pb, Cd) (10 ≤x ≤ 20) glasses of varying composition were recorded in the UV-visible region. Various optical parameters such as optical energy
gap (E
opt), Urbach energy (E
e), refractive index (n
0), optical dielectric constant (ε∞), and ratio of carrier concentration to the effective mass (N/m*;) were determined. The variation of optical energy gap with increase in the concentration of PbCl2 or CdCl2 is discussed. 相似文献