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Flaviu Turcu Simion Simon Serban Constantinescu Nicoleta Grecu Dinu Iuga 《Solid state nuclear magnetic resonance》2009,36(2):92-95
Experimental evidence that nuclear magnetic resonance (NMR) can detect structural changes of piezoelectric La3Ga5SiO14 induced by dilute paramagnetic ions is presented. Gd3+ and Eu3+ cations have been incorporated into La3Ga5SiO14 monocrystals. As expected, the line-width of the tetrahedral 29Si magic angle spinning (MAS) NMR spectra as well as the inverse of the T2 relaxation time of 71Ga increases with the concentration of the paramagnetic ions. A surprising result is shown by 71Ga multiple quantum (MQ) MAS NMR spectrum, which changes with the concentration of paramagnetic ions. The changes in the 71Ga MQMAS spectra can be explained by a more ordonated distribution of Ga ions inside the oxygen tetrahedra. The 71Ga MQMAS NMR spectra allow identification of the one octahedral and two tetrahedral Ga sites. 相似文献
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High optical quality Tm:La3Ga5SiO14 single crystals with dopant concentration of 1 at. % Tm3+ ions were grown by the Czochralski method. The structure was studied by the X-ray powder diffraction method. The absorption spectrum and fluorescence spectrum of Tm3+:La3Ga5SiO14 crystals were measured at room temperature. PACS 42.70.-a; 42.70.Hj; 61.10.Nz; 61.66.Fn; 78.20.-e; 78.90.+t; 81.10.-h 相似文献
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The ESR spectrum of La3Ga5SiO14 single crystals activated by chromium ions is investigated. It is shown that chromium ions are incorporated into the La3Ga5SiO14 crystal lattice in the trivalent state at laoctahedric positions. Orientations of the principal magnetic axes are determined,
and parameters of the spin Hamiltonian are estimated. The effect of disorder of the crystal structure of the matrix on line
widths and shapes of the ESR spectrum of impurity Cr3+ ions is discussed.
I. Franko L’vov State University, 50, Dragomilov St., L’vov, 290005, Ukraine. Translated from Zhurnal Prikladnoi Spektroskopii,
Vol. 65, No. 6, pp. 942–946, November–December, 1998. 相似文献
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Structure and photoluminescence properties of Er3+-doped TiO2-SiO2 powders prepared by sol-gel method 下载免费PDF全文
Er 3+-doped TiO 2-SiO 2 powders are prepared by the sol-gel method,and they are characterized by high resolution transmission electron microscopy (HR-TEM),X-ray diffraction (XRD) spectra,and Raman spectra of the samples.It is shown that the TiO 2 nanocrystals are surrounded by an SiO 2 glass matrix.The photoluminescence (PL) spectra are recorded at room temperature.A strong green luminescence and less intense red emission are observed in the samples when they are excited at 325 nm.The intensity of the emission,which is related to the defect states,is strongest at the annealing temperature of 800 C.The PL intensity of Er 3+ ions increases with increasing Ti/Si ratio due to energy transfer between nano-TiO 2 particles and Er 3+ ions. 相似文献
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S. GeorgescuO. Toma A.M. VoiculescuC. Matei R. BirjegaL. Petrescu 《Physica B: Condensed Matter》2012,407(7):1124-1127
Bright green (at 525 and 550 nm) and red (at 660 nm) luminescence in Er:Yb:La3Ga5.5Ta0.5O14 (LGT) powder synthesized by solid state reaction was obtained by pumping at 936 nm. Yb3+-Er3+ energy transfer processes accounting for population of the 2H211/2, 4S3/2 and 4F9/2 Er3+ levels are discussed. The dependence of ratio between the intensities of the green and red luminescence on pump intensity is analyzed. The rather high quantum efficiency (58%) of the (4S3/2, 2H211/2) Er3+ emitting level recommends LGT doped with erbium and ytterbium for upconversion applications. 相似文献
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Preparation of Er3+, Ho3+ and Tm3+ ions co-doped SiO2 nanoparticle phosphor powders by sol gel method is reported. The morphology and the particle size of the SiO2 host matrix were confirmed by field emission scanning electron microscopy (FESEM). Ultraviolet, visible (UV/VIS) and cathodoluminescence measurements were carried out in order to investigate the optical properties of our powder phosphors. Green emissions at 520 nm from Er3+ and 544 nm from Ho3+, and red emissions at 665 nm from both Er3+ and Ho3+ ions are reported. Another emission peak in the near infra-red (NIR) region at 875 nm from Er3+ was also measured. Blue emission at 460 nm, red at 705 nm and a NIR peak in the region of 865 nm from Tm3+ were observed. Red, green and blue (RGB) colours were measured from both SiO2:Er3+,Tm3+ and SiO2:Ho3+,Tm3+ systems. The change in the intensities of the emission peaks in both the SiO2:Ho3+,Tm3+ and SiO2:Er3+,Tm3+ systems with the change in accelerating beam voltage is shown. Energy transfer from Tm3+ ions to Er3+ and Ho3+ ions was observed. A mechanism explaining the increase and decrease behaviour of the emission with accelerating beam voltage from both systems is reported. 相似文献
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针对稀土Er掺杂Si光源中Er离子掺杂浓度低的问题,采用溶胶-凝胶(Sol-gel)法在Si(100)和SiO2/Si(100)基片上旋涂法制备Er2O3光学薄膜,Er离子浓度与以前掺杂方法相比提高了2个数量级.900 ℃热处理获得单一立方结构的Er2O3薄膜材料.光致发光(PL)特性研究表明在654 nm波长的激光泵浦下,Er2O3薄膜材料获得了1.535 μm的发光峰,并具有较小的温度猝灭1/5.在SiO2/Si(100)基体上制备的Er2O3薄膜材料的光致发光强度比Si(100)基体上制备的薄膜提高2-3倍.研究结果表明具有强光致发光特性的Er2O3薄膜是一种有前景的硅基光源和放大器材料. 相似文献
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采用共沉淀法制备了纳米晶ZrO2-Al2O3∶Er3+发光粉体.所制备的粉体室温下具有Er3+离子特征荧光发射,主发射在绿光,其中位于547 nm、560 nm的绿光最强,并得出稀土离子与基质之间有能量传递.对不同煅烧温度下的样品研究表明:因不同温度下所制得的样品晶相不同.研究了纳米晶ZrO2-Al2O3∶Er3+及ZrO2-Al2O3∶Er3+/Yb3+的上转换发光,并分析了上转换的跃迁机制.发现ZrO2-Al2O3∶Er3+的绿光为双光子过程,而ZrO2-Al2O3∶Er3+、Yb3+的上转换光谱中,红光和绿光也为双光子过程,而极弱的蓝光为三光子过程.讨论了Er3+的浓度猝灭现象.最适宜掺杂浓度的原子分数为2%(Er3+/Zr4+). 相似文献
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制备了系列Er3+/Yb3+共掺碲硼硅酸盐玻璃样品(85-x)TeO2-15B2O3-xSiO2 (TBS x=0,5,10,15,20 mol%).测试和分析了样品的吸收光谱、荧光光谱、能级寿命、红外透射光谱及差热特性.并通过对Er3+离子4I13/2→4I15/2跃迁发射谱线的高斯拟合,设计了一个简单的四能级结构估算了Er3+离子4I13/2和4I15/2能级在碲硼硅酸盐中的Stark分裂情况.研究表明SiO2的引入能有效地改善玻璃的热稳定性和光谱性能,玻璃析晶温度Tx与玻璃转变温度Tg之差(ΔT=Tx-Tg)可达178℃,说明碲硼硅酸盐是一种适合于光纤拉制的玻璃基质材料.比较了不同基质玻璃中Er3+离子的荧光半高宽和受激发射截面,结果表明TBS玻璃系统具有较好的带宽性能,是一种优良的宽带光纤放大器候选基质材料.
关键词:
碲硼硅酸盐
热稳定性
高斯拟合
-基')" href="#">OH-基 相似文献
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I. V. Kityk J. Wasylak D. Dorosz J. Kucharski S. Benet H. Kaddouri 《Optics & Laser Technology》2001,33(7)
Infra-red luminescence (at wavelengths about 1600 and 2500 nm) from Er3+ ions embedded in PbO–Bi2O3–Ga2O3–BaO glass hosts is reported for room and helium liquid temperatures. The substantial influence of energy transfer processes between the host and Er3+ ions is shown experimentally through the dependences of photoluminescence on light polarization and excitation wavelength. Only the application of the polarized pumping YAG–Nd laser beam (λ=1060 nm) stimulates substantial luminescence with quantum efficiency up to 24%. The role of phonon-relaxation subsystem in the observed luminescence is discussed. 相似文献
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测量了不同掺杂浓度下Er3+离子在碲酸盐玻璃中的吸收光谱、发射光谱和Er3+离子的荧光寿命,计算了Er3+离子的发射截面σe,分析 了Er 3+离子掺杂浓度对其发光强度和荧光寿命的影响.结果表明,Er3+离子掺 杂浓度较低时,对其荧光强度和荧光寿命没有显著的影响;掺杂浓度高时,出现了浓度猝灭 效应,使Er3+离 子荧光光强度降低,荧光寿命下降.实验确定了掺杂浓度最优值,同时对浓度猝灭机制进行 了分析.
关键词:
碲锌碱玻璃
3+离子')" href="#">Er3+离子
掺杂浓度
发光和荧光寿命 相似文献
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E2SiO5 thin films were fabricated on Si substrate by reactive magnetron sputtering method with subsequent annealing treatment. The morphology properties of as-deposited films have been studied by scanning electron microscope. The fraction of erbium is estimated to be 23.5 at% based on Rutherford backscattering measurement in as-deposited Er-Si-O film. X-ray diffraction measurement revealed that Er2SiO5 crystalline structure was formed as sample treated at 1100 °C for 1 h in O2 atmosphere. Through proper thermal treatment, the 1.53 μm Er3+-related emission intensity can be enhanced by a factor of 50 with respect to the sample annealed at 800 °C. Analysis of pump-power dependence of Er3+ PL intensity indicated that the upconversion phenomenon could be neglected even under a high photon flux of 1021(photons/cm2/sec). Temperature-dependent photoluminescence (PL) of Er2SiO5 was studied and showed a weak thermal quenching factor of 2. Highly efficienct photoluminescence of Er2SiO5 films has been demonstrated with Er3+ concentration of 1022/cm3, and it opens a promising way towards future Si-based light source for Si photonics. 相似文献
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Masaaki Yamazaki 《Solid State Communications》2004,130(9):637-639
Long-lasting afterglow due to Tb3+ ions has been observed in a Tb3+-doped SiO2-Ga2O3-CaO-Na2O glass, where a 4s empty orbital of Ga3+ probably works as an electron-trapping center. The sensitization effect of Yb3+ on the afterglow has been noticed. 相似文献
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A series of Er3+/Yb3+-co-doped 60Bi2O3-(40−x) B2O3 -xGa2O3 (BBGA x=0, 4, 8, 12, 16 mol%) glasses have been prepared. The absorption spectra, emission spectra, fluorescence lifetime of Er3+:4I13/2 level and thermal stability were measured and investigated. Three Judd-Ofelt intensity parameters Ωt (t=2,4,6) (Ω2=(4.67-5.93)×10−20 cm2, Ω4=(1.50-1.81)×10−20 cm2, Ω6=(0.92-1.17)×10−20 cm2) of Er3+ ions were calculated by Judd-Ofelt theory. It is found that the Ω6 first increases with the increase of Ga2O3 content from 0 to 8 mol% and then decreases, which is mainly affected by the number of non-bridging oxygen ions of the glass network. The high peak of stimulated emission cross-section () of Er3+: 4I13/2→4I15/2 transition were obtained according to McCumber theory and broad full width at half maximum (FWHM=69-76 nm) of the 4I13/2→4I15/2 transition of Er3+ ions were measured. The results indicate that these new BBGA glasses can be used as a candidate host material for potential broadband optical amplifiers. 相似文献
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K.D OskamK.A Kaspers A Meijerink H Müller-BunzTh Schleid 《Journal of luminescence》2002,99(2):101-105
The luminescence properties of Ce3+ in La3F3[Si3O9] are reported. Excitation and emission bands corresponding to 4f1→5d1 transitions of Ce3+ were identified. The center of gravity of the 5d states lies at remarkable high energy (43.2×103 cm−1) for Ce3+ in a silicate compound. This high value is attributed to the combined oxygen/fluoride coordination of the Ce3+ ion. Emission from the lowest 4f5d level to the 2F5/2 and 2F7/2 levels was found at 32.4×103 and 30.4×103 cm−1. These results are compared with literature data on silicates and fluorides. From the values found for Ce3+, predictions are made for the positions of the 4f5d bands of Pr3+ and Er3+ in La3F3[Si3O9]. For both ions, it is concluded that in this host lattice emission is expected from high lying 4fn energy levels. 相似文献