共查询到20条相似文献,搜索用时 31 毫秒
1.
Germanate laser glasses have received much attention as a promising host materials for mid-infrared fiber lasers in recent years because of the outstanding infrared transparency, low phonon energy, and high rare earth solubility of such glasses. However, the development of high-performance germanate laser glasses is usually based on intuition and a trial-and-error method, which can involve long experimental periods and high costs, and thus, this approach is highly inefficient. Recently, with proposals for materials genome engineering, the concept of the “glass genome” has grown of interest to us. Herein, the structures of Tm 3+-doped germanate laser glasses (BaO–GeO 2 and BaO–La 2O 3–GeO 2) were investigated by Fourier transform infrared spectra (FTIR) and Raman spectra analyses, which revealed that the resulting glass contains similar structural groups to the neighboring congruently melted glassy compounds (NCMGCs) in the composition diagram. What is more, the structure and properties of the resulting laser glasses largely depend on NCMGCs. Then, the glass-forming region, physical properties, and luminescence properties were calculated via the use of NCMGCs in Tm 3+-doped BaO–GeO 2 binary and BaO–La 2O 3–GeO 2 ternary laser glass systems. The calculated results were in good agreement with the experimental results, thus demonstrating that our approach is practical for predicting the glass-forming region, physical properties, and luminescence properties in Tm 3+-doped BaO–GeO 2 binary and BaO–La 2O 3–GeO 2 ternary laser glass systems. This work may provide an effective method to develop Tm 3+-doped germanate laser glasses rapidly and at low cost. 相似文献
2.
The near-infrared (NIR) luminescence in S+E+O bands of tellurite glasses doped with Nd 3+/Tm 3+ and Ag nanoparticles (NPs) was investigated. The tellurite glasses were prepared by melt-quenching and heat-treated techniques. Under the excitation of 808 nm laser, Nd 3+/Tm 3+ doped tellurite glasses produced three NIR luminescence bands of 1.33, 1.47 and 1.85 μm, originating from Nd 3+: 4F 3/2→ 4I 13/2, Tm 3+: 3H 4→ 3F 4 and Tm 3+: 3F 4→ 3H 6 transitions respectively. Interestingly, a broadband luminescence spectrum ranging from 1280 to 1550 nm with the FWHM (full width at half maximum) about 201 nm was obtained due to the overlapping of the first two NIR bands. Further, the peak intensity of this broadband luminescence was increased by 75% after the introduction of Ag NPs with diameter in 10–20 nm. The analysis of fluorescence decay shows that compared with the enhanced local electric field, the energy transfer from Ag species to Nd 3+ and Tm 3+ ions plays a major role in luminescence enhancement. The findings in this work indicate that tellurite glass co-doped with Nd 3+/Tm 3+ and Ag NPs is a potential gain material applied in the S+E+O-band photonic devices. 相似文献
3.
Nd 3+-doped phosphate laser glasses have been attracting much attention and widespread investigation due to their high solubility of rare earth (RE) ions, excellent spectroscopic properties, and large damage threshold. However, the narrow NIR emission bandwidth (less than 30 nm) of these Nd 3+-doped phosphate glasses limits their further application toward ultrahigh power field and efficient fiber laser in new region. Here, we demonstrate the broadening and enhancing of Nd 3+ NIR emission in laser glass of zinc aluminophosphate through tuning the glass structure and covalency of Nd-O bond without limiting the radiative properties of Nd 3+. The maximum bandwidth of 1.05 μm emission is broadened to 50 nm, which is comparable to that of Nd 3+-doped aluminate laser glasses. Simultaneously, the lifetime of 4F 3/2 level is elongated nearly by two times. Structural and optical properties of prepared glasses were discussed systematically to reveal the mechanism. Detailed analysis on optical spectra and glass structure indicates that the bandwidth is affected by not only the covalency of Nd-O but also the compactness of glass structure. Our results could enrich our understanding about the relationship between local glass structure and luminescence behaviors of active centers, and may be helpful in designing new RE-doped laser glass systems. 相似文献
4.
In this work, we revealed the possible mechanisms of the photodarkening in Pr 3+ ions singly doped and Pr 3+/Ce 3+ co-doped silicate glasses and fibers induced by X-ray and 488-nm laser radiations and studied the role of Ce 3+ in increasing radiation resistance in Pr 3+-doped silicate glasses and fibers. The absorption, emission, electron paramagnetic resonance (EPR), radiation induced attenuation spectra, and X-ray photoelectron spectroscopy (XPS) of Pr 3+ singly doped and Pr 3+/Ce 3+ co-doped silicate glasses before and after X-ray radiation were measured and analyzed. The fluorescence intensity and photoinduced attenuation of Pr 3+ singly doped and Pr 3+/Ce 3+ co-doped silicate fibers at visible wavelengths pumped by 488-nm laser were measured and analyzed. The influence of Ce 3+ ions co-doping on the spectroscopic properties of Pr 3+ ions as well as the radiation-induced defects in silicate glasses was studied. Results demonstrate that both X-ray and 488-nm laser radiations will induce photodamage in Pr 3+ ions-doped silicate glasses and fibers. Co-doping Ce 3+ (by up to 1 mol%) is efficient to suppress the darkening induced by both X-ray and 488-nm laser radiations without influence on the luminescence behavior of Pr 3+ ions in silicate glasses and fibers. Our studies demonstrate the promising potential of Pr 3+/Ce 3+ co-doped silicate glasses for visible lasing applications. 相似文献
5.
In the paper, the upconversion luminescence of 70GeO 2–30[Ga 2O 3–BaO–Na 2O] glass system co-doped with Yb 3+/Tm 3+ ions was investigated. Strong blue emission at 478 nm corresponding to the transition 1G 4 → 3H 6 in thulium ions was measured under the excitation of 976-nm diode laser. The dependence of the upconversion emission upon the thulium ion concentration was studied to determine the optimal conditions of energy transfer between energy levels of active dopants. The most effective energy transfer Yb 3+ → Tm 3+ was obtained in glass co-doped with molar ratio of dopant 0.7 Yb 2O 3/0.07 Tm 2O 3. The increase in thulium concentration more than 0.07 mol% results in the reverse energy transfer from Tm 3+ → Yb 3+, which leads to rapid quenching of the luminescence line at the wavelength 478 nm. In germanate glass co-doped with 0.7Yb 2O 3/0.07Tm 2O 3, the longest lifetime of 1G 4 level equal 278 μs was achieved. The presented results indicate that elaborated germanate glass co-doped with Yb 3+/Tm 3+ ions is a promising material that can be used to produce fiber lasers and superluminescent fiber sources generating radiation in the visible spectrum. 相似文献
6.
Tm 3+-singly-doped and Tm 3+-/Ho 3+-codoped TeO 2-Bi 2O 3-ZnO-Li 2O-Nb 2O 5 (TBZLN) tellurite glasses were successfully prepared by the melt-quenching technique. Emission characteristics and energy transfer mechanisms were studied upon 785-nm laser diode excitation. A significant enhancement of emission intensity at 1.81 μm with increasing concentration of Tm 3+ ions has been observed while increase in the emission intensity at 2.0 μm with increasing concentration of Ho 3+ has been observed up to the equal concentration of Tm 3+ (0.5 mol%) in TBZLN glasses. The stimulated emission cross section of Tm 3+: 3F 4→ 3H 6 (5.20×10 −21 cm 2) and Ho 3+: 5I 7→ 5I 8 (4.00×10 −21 cm 2) in 1.0 mol% Tm 3+-doped and 0.5 mol% Tm 3+/1.0 mol% Ho 3+-codoped TBZLN glasses are higher compared with the reported and are found to be excellent candidates for solid-state lasers operating at ~1.8 and 2.0 μm, respectively. The extension of near-infrared (NIR) emission of Tm 3+ with Ho 3+ ions provides the possibility of using these materials for broadband NIR amplifiers. 相似文献
7.
NaY(WO 4) 2 is one of the excellent host materials for high-efficient upconversion luminescence, but it is still challenging to obtain red emission via lanthanide doping. In this work, pure red emission was achieved in the heavily-Er 3+-doped NaY(WO 4) 2 by using a 1550 nm laser diode and introducing mediator Tm 3+ ions in the lattice. On basis of the analysis of steady-state and transient-state luminescence properties related to dopant concentration and excitation wavelength, all possible red emission mechanisms were discussed. Finally, it has been demonstrated that the high-purity red emission was due to the several energy transfer processes between Er 3+ and Tm 3+. Our results provide a convenient pathway to investigate the upconversion luminescence mechanisms. 相似文献
8.
Tellurite glasses doped with Tm 3+, Ho 3+ and Ce 3+ ions were prepared via melt-quenching to realise broadband and fluorescence enhancement in near-infrared (NIR) band. Under the pumping of a commercial 808 nm laser diode (LD), the emission bands at 2.0 μm, 1.85 μm, 1.47 μm, and 705 nm were observed in the Tm 3+/Ho 3+ co-doping glass samples, which originated from the transitions of Ho 3+: 5I 7→ 5I 8 and Tm 3+: 3F 4→ 3H 6, 3H 4→ 3F 4, 3F 2,3 → 3H 6, respectively. The existence of 2.0 μm band fluorescence is due to the energy transfer from the Tm 3+: 3F 4 level to the Ho 3+: 5I 7 level. This band overlaps with the 1.85 μm band which forms a broadband fluorescence spectrum in the range of 1600–2200 nm. In glass samples co-doped with Tm 3+/Ho 3+ with 0.085 mol% Ho 2O 3 and 1 mol% Tm 2O 3, the full width at half maximum (FWHM) of this broadband spectrum (1600–2200 nm) was as high as ∼370 nm. After introducing 0.6 mol% CeO 2, the emission intensity of broadband fluorescence increased by ∼50%, which was caused by the cross-relaxations between Ce 3+ and Tm 3+ ions. The lifetime of fluorescence decay was determined to prove the interactions among the doped rare-earth ions, the radiative parameters such as transition probability, branching ratio and radiative lifetime were calculated from the absorption spectra based on the Judd-Ofelt theory to better understand the observed luminescence phenomena. In addition, X-ray diffraction (XRD) confirmed the amorphous state structure of the synthesised glass samples, while Raman spectrum revealed the different vibrational structural units forming the glass network. 相似文献
9.
Eu 3+/Nd 3+ co-doped multicomponent borosilicate glasses (ND1E: 10BaO +10ZnF 2+10K 2O +20SiO 2+(49-x) B 2O 3+1Nd 2O 3+xEu 2O 3) were prepared by conventional melting and rapid quench technique to evaluate the effect of Eu 3+ ions in the Nd 3+ doped glasses. Thermal stability, structural and spectroscopic characteristics of the ND1E glasses were investigated by using DSC, XRD, FTIR, Optical absorption, excitation and emission measurements. The Judd – Ofelt (JO) analysis is implemented to the absorption spectrum of the prepared glassy matrix in order to identify their potential applicability in lasing devices. Enhancement of 7F 0 → 5L 6 band (394 nm) with the increasing concentration of Eu 3+ ion in the Nd 3+ excitation spectra (λ emi = 1060 nm) reveals the possibility of obtaining the characteristic fluorescence spectra of Nd 3+ ion with the typical excitation wavelengths (Nd 3+ = 584 nm and Eu 3+ = 394 nm) of both rare earth ions and it is further verified from the emission spectrum. This interesting luminescence effect of showing excellent visible and NIR emission under 394 nm excitation mainly attributes the energy transfer mechanism between the RE 3+ ions and the reason underlying this effect is discussed in detail with the help of partial energy level diagram. Energy transfer efficiency between the Eu 3+ and Nd 3+ ions were evaluated by using the radiative lifetimes of the prepared glasses. Also, a comparison of radiative properties and lasing characteristics of Eu 3+/Nd 3+ co-doped glasses with other Nd 3+ glasses are reported. The emission intensities were characterized using CIE chromaticity diagram and the observed CIE coordinates shows a shift towards reddish – orange region with the increase in Eu 3+ concentration. The quantum efficiency of the prepared glasses was determined experimentally. The obtained results suggest that the ND1E glassy system can be considered as a potential candidate for visible and NIR luminescence applications. 相似文献
10.
Lanthanide-doped upconversion photoluminescent nanoparticles with unique anti-Stokes spectroscopic properties excel in many fields of application. Ytterbium-based self-sensitized fluorides with rich Yb 3+ possess higher absorption efficiency of incident near infrared laser, and are more favorable for photoluminescence or optical heating applications. In this work, α-NaYbF 4:Tm 3+ crystalline nanoparticles are synthesized, which exhibit intense ultraviolet self-sensitized upconversion photoluminescence and highly efficient optical heating capability under 980 nm laser excitation. NaYbF 4:Tm 3+ nanocrystals emit multi-band luminescence with emission peaks located in the ultraviolet, blue and red spectral regions. The energy transfer mechanism and electronic transition pathways for the Upconversion luminescence are investigated based on the energy level scheme, and are further confirmed by luminescent dynamic analysis. Due to cross-relaxations between Tm 3+ and energy back transfer from Tm 3+ to Yb 3+ processes, the NaYbF 4: 1 mol% Tm 3+ nanoparticles possess the highest luminescence intensity. The luminescent dynamic characteristics, such as decay time and rise time, vary with Tm 3+ doping concentrations. Highly efficient optical heating effect is observed in the NaYbF 4:Tm 3+ nanoparticles with slope efficiency of photothermal conversion for 10 s laser irradiation is as high as 100.48 °C/W. 相似文献
11.
Melt-quenched Pr3+-doped phosphate glass containing Cu+ and Sn2+ as redox couple to induce Cu nanoparticle (NP) precipitation was subjected to heat treatment to develop nanocomposite glasses with plasmonic and dichroic character. The purpose was to examine the impact of Cu NPs producing dichroism on the near-infrared (NIR) emission from Pr3+. The parent and isothermally heat-treated glasses (520?°C: 20, 40, 60?min) were characterized by differential scanning calorimetry, Fourier transform-infrared spectroscopy, optical extinction, and photoluminescence spectroscopy with decay dynamics. From the samples, the heat-treated for 40 and 60?min showed broad plasmonic bands alongside dichroism wherein the glasses scatter red light but transmit blue. The Pr3+ NIR emission encompassing 1D2 → 3F4, 3F3,1G4 transitions was evaluated under 445 and 590?nm excitation. An increased emission was not exhibited, whereas a quenching effect became evident for samples heat-treated for 40 and 60?min. Different interactions involving Pr3+ ions and Cu NPs are discussed. 相似文献
12.
Glasses with ultra-wideband near-infrared emission and superior irradiation resistance are important for the potential applications in optical communications under harsh environments. Here, transparent 35La 2O 3-(65- x)Ga 2O 3- xTa 2O 5 (LGT) and Er 3+/Tm 3+/Pr 3+ tri-doped LGT glasses are fabricated using the levitation method. LGT glasses exhibit a wide glass-formation region, low largest vibration energy, high refractive indices, and excellent mechanical properties. Additionally, Er 3+/Tm 3+/Pr 3+ tri-doped LGT samples with varying Pr 3+ contents are characterized by possessing good thermal stability ( Tg>849°C), wide transparent optical window, strong radiation resistance, excellent compatibility between low wavelength dispersion ( vd>31.2), and large refractive index ( nd>2.048). By optimizing the doping content of Er 3+, Tm 3+, and Pr 3+ in an appropriate ratio, the ultra-wideband near-infrared luminescence ranging from 1250 to 1640 nm (FWHM = 251 nm) has been acquired under 808 nm pumping. Furthermore, decay curves are measured to reveal the fluorescence dynamics, and then the related emission mechanism is elaborated systematically. Meanwhile, the effects of gamma irradiation doses on microstructure, transmittance spectra, and fluorescence characteristics are studied. This work may offer a valuable reference for doping optimization and new design strategy of multifunctional materials. 相似文献
13.
Super broadband near-infrared (NIR) La 3Ga 5GeO 14(LGGO): Cr 3+ phosphor is in urgent needs for food testing. Unfortunately, it suffers from poor luminescence intensity in applications. Herein, the enhanced NIR luminescence performance can be realized in LGGO: Pr 3+, Cr 3+. The preferential crystallographic site of Cr 3+ is validated on the basis of EPR spectrum, Rietveld refinement, and the first-principles DFT calculations. It is of great importance that the as-prepared phosphors can be excited by blue light (460 nm), which is beneficial to the application of blue-pumped LEDs. The critical distance of Pr 3+ in LGGO host has been calculated by concentration-quenching method. For co-doped sample, it is observed that Cr 3+ luminescence intensity enhancement by a factor of 3 can be achieved by doping Pr 3+ owing to the energy transfer from Pr 3+ to Cr 3+. In addition, the introduction of Pr 3+ can also improve the Cr 3+ luminescence intensity at elevated temperature. Furthermore, using the optimized phosphor, a blue-based NIR phosphor-converted LEDs (NIR pc- LEDs) is fabricated, the forward voltage and the intensity of LED hardly change after thermal aging for 500 hours under high temperature/ high humidity condition, indicating its great reliability for NIR pc-LEDs. Therefore, LGGO:Pr 3+, Cr 3+ has great potential to serve as an attractive candidate in the application of blue light-excited NIR pc-LEDs in view of its capability for blue to enhanced broadband NIR conversion. 相似文献
14.
In contrast to Yb 3+ which is a well-investigated optically active ion, the spectroscopic properties of its divalent counterpart Yb 2+ in glasses are hardly investigated, although Yb 2+ might have a notable influence on the luminescence properties of Yb 3+-doped glasses even at low Yb 2+ concentrations because of its strong f-d transitions. In this paper, we report on the preparation and spectroscopic properties of Yb 2+-doped aluminosilicate glasses that were produced using the normal melt-quench technique. The glass composition is 20CaO·20Al 2O 3·60SiO 2 (mol%). To achieve a sufficient amount of Yb 2+ in the samples, different methods were applied to influence the red-ox equilibrium during glass melting: firstly, under argon atmosphere and additional argon bubbling, and secondly by the addition of metallic aluminum powder to the batch. The strongly reduced samples show a greenish to brownish yellow coloring which could be attributed to the strong absorption of Yb 2+ ions in the UV to blue spectral range. The absolute Yb 2+ concentration in the glass and the molar extinction coefficient of Yb 2+ was obtained by spectroscopic measurements. If irradiated with UV light, the Yb 2+-doped samples show a broad fluorescence emission in the wavelength range from 450 to 700 nm with a peak at around 515 nm. 相似文献
15.
In this work, Pr 3+ ion-doped Ge 20Ga 15−xSb xSe 65 ( x = 0, 5, 10, in mol%), Ge 20Sb 15−yIn ySe 65 ( y = 5, 10, in mol%), Ge 20Ga 15−zIn zSe 65 ( z = 0, 5, 10, in mol%), and Ge 20Ga 5Sb 10Se 60I 5 glasses were prepared. The structural units, thermal properties, and optical properties of these glasses were analyzed. In addition, a comprehensive comparison study of the effects of metal ions (Sb, Ga, and In), S/Se ratio, and I content on the mid-infrared (MIR) luminescence of Pr 3+ ions was conducted. Under a 1.55-μm laser pump, 0.2 mol% of Pr 3+ ion-doped chalcogenide glasses performed strong photoluminescence in the wavelength range of 3.5-5.5 μm. Results indicated that the Sb-containing glass performed the strongest emission intensity among the studied glasses. Moreover, halogen element I can reduce the phonon energy of the matrix, which is beneficial to the luminescence of Pr 3+ ions and provide significant possibilities for developing MIR lasers and amplifiers. 相似文献
16.
Rare‐earth‐doped oxyfluoride germanate and borate glasses were synthesized and next studied using spectroscopic methods. Influence of fluoride modifier on luminescence properties of rare earths in different glass hosts was examined. The excitation and emission spectra of Pr 3+ and Er 3+ ions in the studied glasses were registered. The emission spectra of Pr 3+ ions in germanate and borate glasses are quite different and depend strongly on the glass host. In samples doped with Er 3+ ions emission bands located around 1530 nm corresponding to the main 4I 13/2→ 4I 15/2 laser transition were registered, independently of the glass host. Quite long‐lived near‐infrared luminescence of Er 3+ ions was observed for germanate glasses with low BaF 2 content, while in borate glass systems influence of barium fluoride on luminescence lifetimes is not so evident. The Judd–Ofelt calculations were used in order to determine quantum efficiencies of excited states of rare‐earth ions in germanate and borate glasses. 相似文献
17.
In this paper, Tm 3+ doped pure tellurite glass, TiO 2 modified tellurite glass and TiO 2/GeO 2 co-modified tellurite glasses were prepared. The effects of the introduction of TiO 2 and GeO 2 oxides on the thermal, structural, optical properties of tellurite glasses were compared and analyzed intensively. Besides, the Judd-Ofelt intensity parameters and absorption and emission cross sections were calculated. DTA curves indicated the thermal stability of pure tellurite glass enhance obviously by GeO 2 modification. The introduction of TiO 2 and GeO 2 oxides in tellurite glasses arise a series of variation on the absorbance, luminescence peak position and fluorescence intensity which have been explained and analyzed in detail. Based on the analysis, the addition of TiO 2 in tellurite glass contributes to the improvement of 2 μm fluorescence performance, and the introduction of GeO 2 has great advantages in enhancing the thermal stability of glass. 相似文献
18.
Transparent Pr 3+ doped Ca 1-xGd xF 2+x (x = 0, 0.01, 0.03, 0.06, 0.10, 0.15) polycrystalline ceramics with fine-grained microstructures were prepared by the hot-pressing method. The dependence of microstructure, optical transmittance, luminescence performances and mechanical properties on the Gd 3+ concentrations for Pr 3+:Ca 1-xGd xF 2+x transparent ceramics were investigated. The Gd 3+ ions show positive effects on the microhardness of Pr 3+:Ca 1-xGd xF 2+x transparent ceramics as a result of the decrease in the grain sizes. Excited by the Xenon lamp of 444 nm, typical visible emissions located at 484 nm, 598 nm and 642 nm were observed. Furthermore, the incorporation of Gd 3+ ions can greatly enhance the photoluminescence performance owing to the improvement in the concentration quenching effect. The quenching concentration of Pr 3+ ions in CaF 2 transparent ceramics increased to 1 at.% as a result of the positive effect of Gd 3+ codoping. The energy transfer mechanism of Pr 3+ in the Pr 3+:Ca 1-xGd xF 2+x transparent ceramics has been investigated and discussed. 相似文献
19.
A new glass series with nominal molar composition of 60B 2O 3 + 30NaF + 10Al 2O 3 co-doped with Dy 3+ and Pr 3+, synthesized by melt quench was reported. The influence of Rare Earth (RE) ratio variation on prepared glasses was investigated by using Fourier Transform Infra-Red spectroscopy, UV–Vis–NIR absorption spectroscopy, Photoluminescence, Decay curves and Density measurements. Their X-Ray Diffraction and FTIR spectra revealed the glassy nature and confirmed that AlO 6, AlO 4, BO 3 and BO 4 units are the main structural units of that matrix. A non-linear variation following the same trend for tetragonal borate units (N 4), Band gap, non-linear optical properties, Density, Molar Volume etc. was observed. Different optical parameters were obtained by UV–Vis–NIR spectroscopy. The Bonding parameter obtained from Nephelauxetic study indicated ionic nature of Dy 3+ and covalent nature of Pr 3+ ions. Photoluminescence excitation and emission spectra were recorded under variety of excitation wavelengths and corresponding color parameters were calculated using 1931 CIE standards. A detailed yellow to blue ratio analysis was reported as a function of RE ion concentration and excitation wavelengths. Composition DPNAB( x = 0.7) displayed the best performance with CIE coordinates (0.33, 0.37). Existence of Energy transfer from Dy 3+ and Pr 3+ was evidenced by the spectral overlap diagram and lifetime values obtained from fitting of Decay curves. From the obtained results, prepared glasses can be suggested for solid-state lighting devices like WLEDs and display devices. 相似文献
20.
Er 3+ single doped fluoroaluminate-tellurite glasses were made by employing a conventional melt-quenching technique. A strong fluorescence around 3.1 μm was achieved from Er 3+-doped fluoride glasses, under a 980 nm laser diode pump, which was assigned to the Er 3+: 4S 3/2 → 4F 9/2 radiation transition process. The up-conversion and mid-infrared spectra of emission for fluoroaluminate-tellurite glasses with various concentrations of Er 3+ ions dopant was researched. In addition, the calculated fluorescence lifetime value about 3.1 μm reaches 0.48 ms. The findings indicate that fluoroaluminate-tellurite glasses doped with Er 3+ have prospects of being developed into 3.1 μm mid-infrared fiber and laser materials. 相似文献
|