Yb:Y2－2xLa2xO3激光透明陶瓷的光谱性能

对一种低温易烧结的Yb:Y_2-2xLa_2xO₃激光透明陶瓷的光谱性能进行了初步研究，Yb:Y_2-2xLa_2xO₃激光透明陶瓷具有宽的吸收带和大的吸收截面，在最强的吸收峰977nm处吸收截面达4.0×10^-20cm²；其荧光发射寿命为1.1ms，发射截面在1033nm处为1.0×10^-20cm²，在1077nm处为0.7×10^-20cm².Yb:Y_2-2xLa_2xO₃陶瓷的各项光学性能指标接近或达到单晶的指标. 关键词： 氧化镧钇 激光陶瓷 低温烧结 光谱性能     

Nd3+螯合物的含氢有机溶液光谱性能研究

研究了Nd(TTA)₃螯合物溶于二甲基甲酰胺溶剂的光谱性质，溶液中所有氢未置换为氘.测量了这种溶液体系的吸收谱、荧光谱和荧光寿命.在898和1058 nm波长处观察到明显的Nd³⁺荧光特征峰.用Judd-Ofelt理论对吸收谱进行分析计算，得到了三个强度参数Ω_t(t=2,4,6)分别为Ω₂=4.9×10^-20 cm², Ω₄=5.1×10^-20 cm²和Ω₆=2.5×10^-20 cm².利用强度参数计算了⁴F_3/2能级与⁴I_9/2和⁴I_11/2之间的跃迁强度S_ed、自发辐射系数A_ed以及荧光分支比β等，估算了⁴F_3/2能级的辐射跃迁寿命τ_r＝682 μs.实测1058和898 nm波长处荧光寿命τ大约为460和505 μs，因此荧光量子效率分别高达0.67和0.74.荧光量子效率高表明Nd³⁺在这种溶液中无辐射跃迁比较弱；强度参数Ω₂比较大，表明Nd³⁺在溶液中具有不对称配位场环境，不对称的配位场环境可大大促进Nd³⁺吸收激发能量.光谱质量因子Ω₄/Ω₆>1，使得898 nm的辐射强于1058 nm的辐射. 关键词： Nd 有机溶液 光谱性能 Judd-Ofelt理论     

Sr位Nd掺杂对SrBi$lt;sub$gt;2$lt;/sub$gt;Nb$lt;sub$gt;2$lt;/sub$gt;O$lt;sub$gt;9$lt;/sub$gt;性能的影响及机理研究

采用传统固相法制备了（Sr_1-3x/2A_x/2Nd_x）Bi₂Nb₂O₉（x=0,0.05,0.1和0.2）陶瓷,并系统研究了Nd离子取代Sr离子对SrBi₂Nb₂O₉性能的影响及其作用机理.研究结果表明：Sr_1-3x/2A_x/2Nd_xBi₂Nb₂O₉的介电常数和介电损耗随温度变化的行为具有明显的离子松弛极化特征.Nd³⁺对Sr²⁺的部分取代,导致Sr_1-3x/2A_x/2Nd_xBi₂Nb₂O₉剩余极化强度P_r稍有下降,但其压电系数d₃₃却有所增加,根据铁电热力学理论,这是Nd³⁺对Sr²⁺取代导致材料介电常数增大所致.Sr_1-3x/2A_x/2Nd_xBi₂Nb₂O₉的居里温度（T_C）没有随Nd含量的增加而变化,拉曼光谱技术分析表明这是其NbO₆八面体畸变程度没有发生变化所致.Nd³⁺取代Sr²⁺提高了材料的介电常数ε_r、压电系数d₃₃、机电耦合系数K_p,同时降低了机械品质因数Q_m,但是谐振频率温度系数C值没有改变. 关键词： 压电陶瓷 介电性能 压电性能 拉曼光谱     

La2O3对Yb:Y2O3透明陶瓷光谱性能的影响

研究了La₂O₃对Yb：Y₂O₃透明陶瓷光谱性能的影响，添加适量La₂O₃以后，Yb：Y₂O₃透明陶瓷的吸收峰和发射峰的位置不变，但由于La³⁺的离子半径大于Y³⁺的离子半径，在Y₂O₃中引入La³⁺离子后，导致Y₂O₃晶格常数变大，晶场强度变弱，同时降低了Y₂O₃晶体的有序度，致使发射峰强度有所下降，发射截面变小.过量的La₂O₃（x=0.16）造成Yb³⁺激活离子发射强度明显下降；其荧光寿命在添加La₂O₃后总体增大45%—60%. 关键词： 氧化镧 氧化钇 透明陶瓷 光谱性能     

808 nm/980 nm近红外光激发下CaSc2O4:Er,Nd纳米晶的上转换发光特性(英文)

通过水热法合成了一系列CaSc₂O₄:Er³⁺,Nd³⁺纳米晶。随着Nd³⁺浓度和激发波长的变化,详细研究了CaSc₂O₄:Er³⁺,Nd³⁺氧化物在可见光和近红外(NIR)区域的发光特性。在808 nm激发下,Er³⁺离子的发光强度随着Nd³⁺离子浓度的增加出现增强。相对的红色强度也有轻微的增强。在980 nm激发下,Nd³⁺离子几乎不吸收980 nm的光子,只有Er³⁺离子的吸收和发射被发现。相对的红色强度没有变化。此外,在近红外光谱中,只观察到Er³⁺离子的发射,这与可见光光谱一致。详细的研究揭示了新型CaSc₂O₄:Er³⁺,Nd³⁺纳米晶在808 nm和980 nm近红外激发下的上转换发...     

Ga2O3组分对Tm3+掺杂GeO2-Ga2O3-Li2O-BaO-La2O3玻璃的光谱性能影响

制备了Tm³⁺(8.0mol%)掺杂(77-x)GeO₂-xGa₂O₃-8Li₂O-10BaO-5La₂O₃(x=4,8,12,16)系列玻璃.系统地研究了Ga₂O₃从4mol%变化到16mol%时,玻璃的光谱性质与热学性质的变化规律.差热分析表明,随着Ga₂O₃含量的增加,锗酸盐玻璃的热稳定性增加.运用Judd-Ofelt(J_O)理论计算得到了Tm³⁺在不同Ga₂O₃含量的GeO₂-Ga₂O₃-Li₂O-BaO-La₂O₃玻璃中的J-O强度参数(Ω₂,Ω₄,Ω₆)及Tm³⁺各激发能级的自发跃迁概率、荧光分支比以及辐射寿命等光谱参量.在808nm激光二极管的激发下,测试并分析了Ga₂O₃对Tm³⁺荧光光谱特性的影响.随着Ga₂O₃从4mol%增加到16mol%,Tm³⁺在1.8μm处的荧光强度呈现先减弱后增强的特性.当Ga₂O₃含量大约在12mol%时,Tm³⁺在1.8μm处的荧光强度最弱,受激发射截面达到最小.还初步讨论了Ga₂O₃对玻璃结构与光谱参数的影响规律. 关键词： 3+掺杂锗酸盐玻璃')" href="#">Tm³⁺掺杂锗酸盐玻璃 光谱性能 Judd-Ofelt参数 热稳定性     

WO3对掺铒碲酸盐玻璃光谱性质的影响

制备了掺铒碲钨酸盐玻璃(80-x)TeO₂-(10+x)WO₃-8BaO-2Na₂O-0.5Er₂O₃(x=0,5,10,15,20)玻璃,研究了WO₃对掺铒碲钨酸盐玻璃的光谱性质. 研究发现：随着WO₃含量的增加,Ω₄,Ω₆先增加后减小,受 关键词： 碲钨酸盐玻璃 3+光谱性质')" href="#">Er³⁺光谱性质 Judd-Offelt理论     

Tm3+掺杂锗铌酸盐玻璃及其红外光谱特性

用高温熔融法制备了相同质量百分比浓度4%Tm₂O₃掺杂浓度下(90-x)GeO₂-xNb₂O₅-10Na₂O(其中数字为摩尔百分比x=1,2,4,6,8)以及Tm₂O₃掺杂浓度分别为质量百分比1%,2%,3%,4%下86GeO₂-4Nb₂O₅-10Na₂O(其中数字为摩尔分数)系列玻璃.研究了Nb₂O₅组分对玻璃热稳定性,荧光强度和J-O参数的影响.应用Judd-Ofelt理论,计算了Tm³⁺离子在Nb₂O₅浓度不同时的J-O强度参数(Ω₂,Ω₄,Ω₆)及Tm³⁺离子各激发态能级的自发跃迁概率、荧光分支比以及辐射寿命等光谱参量.根据McCumber理论,计算了Tm³⁺离子能级³F₄→³H₆(1.8 μm)跃迁的吸收截面和受激发射截面.从获得的吸收截面、发射截面与离子掺杂浓度计算了1.8 μm荧光波段的增益截面曲线.在808 nm波长光的激发下,研究了Tm³⁺掺杂玻璃在1.47与1.8 μm附近的荧光特性.发现当Tm₂O₃掺杂浓度为质量百分比3%时,在1.8 μm处的荧光强度达最大,然后随着掺杂浓度的增大,其荧光强度反而降低;当Nb₂O₅摩尔分数含量大约在2%时,Tm³⁺在1.8 μm处的荧光强度最强.并讨论了Nb₂O₅组分变化对玻璃结构与光谱特性的影响情况. 关键词： 3+掺杂锗铌酸盐玻璃')" href="#">Tm³⁺掺杂锗铌酸盐玻璃 红外光谱性质 交叉弛豫 2O₅')" href="#">Nb₂O₅     

自受激拉曼晶体Nd3+:SrMoO4的光谱性质研究

通过拉曼散射光谱，吸收光谱，荧光发射寿命和808 nm LD激发下的红外荧光光谱的实验测量，系统研究了Nd³⁺:SrMoO₄晶体的自受激拉曼光谱性质.分析指认了拉曼散射光谱中各拉曼峰所对应的晶格振动模式，得出了其SRS活性最强的声子频率约为898 cm^-1，对应于(MoO^2-₄)离子团的完全对称光学伸缩振动A_g模；通过J-O理论对晶体的吸收谱进行了全面的光谱参数计算，得出⁴F_3/2→⁴I_11/2跃迁的积分发射截面达0.57×10^-18 cm²，自发辐射概率为141.06 s^-1；同时，实验测得该跃迁的荧光发射寿命约为0.2 ms.最后，结合808 nm LD激发下的红外波段荧光光谱，论证了SrMoO₄晶体中Nd³⁺离子1068 nm发射通过拉曼频移获得1180 nm一级斯托克斯激光发射的可能性，为Nd³⁺:SrMoO₄晶体的自受激拉曼激光器研究提供了理论依据. 关键词： 3+离子')" href="#">d³⁺离子 4 晶体')" href="#">SrMoO₄ 晶体 自受激拉曼散射     

Cr3+:Al2O3透明多晶陶瓷光谱特性分析

对透光性良好的Cr³⁺:Al₂O₃透明多晶陶瓷的光谱性能 进行了研究，其吸收光谱中吸收峰与单晶红宝石相一致，按吸收光谱和Tanabe-Sugano能级 图，算出其晶场强度参数D_q及Racah参数B分别为1792cm^-1， 689cm ^-1，D_q/B=2.6，陶瓷中Cr³⁺离子所处格位的晶体场强 比单晶弱一些，但Cr³⁺:Al₂O₃透明陶瓷仍属于强场晶 体材料；当Cr³⁺掺杂浓度到达0.8wt%时，陶瓷的发射谱仍保持较好的R线发射 ；随Cr³⁺掺杂浓度的增大，激发峰位发生“红移”.在Cr³⁺:Al₂O₃透明多晶陶瓷的荧光谱上，发现一个波长为670nm的发射峰，经激发 谱确认为Cr³⁺的发射峰. 关键词： 氧化铝 透明陶瓷 离子格位 光谱性质     

Combustion synthesis of a nanoceramic and its transparent properties

La_0.1Nd_0.1Y_1.8O₃ transparent ceramics nanopowders were prepared using the combustion synthesis. To achieve such transparent ceramics, Y₂O₃ were used as matrix materials and La³⁺ and Nd³⁺ were used as dopants, polyethyleneglycol (PEG) as dispersants for the sintering under vacuum 10⁻³ Pa and 1600 °C for 6 h. The precursor and powders calcined at different temperatures were characterized using TG-DTA, XRD, BET and FESEM. The transmittance of the transparent ceramics was measured using the sub-photometer. Results showed that La³⁺ and Nd³⁺ were completely dissolved into the cubic lattice of Y₂O₃. The sizes of Y_1.8La_0.1Nd_0.1O₃ powders were uniform and spherical-like. The particle sizes of powders gradually increased with increasing the calcination temperature. The dispersant can effectively prevent the powders from the agglomeration, and the particle sizes of powders gradually increased with increasing citric acid. The transmittance of the Y_1.8La_0.1Nd_0.1O₃ transparent ceramics was close to its theoretical value (80%).     

Raman spectroscopic investigation of lanthana‐doped neodymium‐yttria transparent ceramics

Transparent ceramics of the formula (Nd_0.01La_xY_0.99−x)₂O₃ (x = 0, 0.05, 0.10) were made with nanopowders and sintered in H₂ atmosphere. The Raman spectra of Ln₂O₃ (Ln = Y, La, Nd) powders and (Nd_0.01La_xY_0.99−x)₂O₃ ceramics were investigated. The results show that both La₂O₃ and Nd₂O₃ powders are of hexagonal structure, and all (Nd_0.01La_xY_0.99−x)₂O₃ ceramics exhibit the same cubic Y₂O₃ crystal structure. Their lattice parameters were refined by the Rietveld method. The full‐widths at half‐maximum of Raman peaks increase with the increase in La₂O₃ content in transparent (Nd_0.01Y_0.99)₂O₃ ceramics, while their intensities decrease. At the same time, All Raman peaks shift to lower wavenumbers, and the phonon energy is slightly reduced. Copyright © 2010 John Wiley & Sons, Ltd.     

Lithium ion conductivity of the B-site substitution in Li3xLa0.67−xRE y III Ti1−2yPyO3 system (REIII=Sc3+, Y3+, Nd3+, Sm3+, Eu3+, Yb3+)

The B-site substituted perovskite solid solution systems Li_3xLa_0.67−xRE_yTi_1−2yP_yO₃ (RE=Sc, Y, Nd, Sm, Eu, Yb) have been investigated. Perovskite solid solutions formed in the range of x=0.10, y<0.10 for RE=Sc³⁺, Y³⁺, Yb³⁺, x=0.10, y≤0.05 for RE=Nd³⁺, Sm³⁺, Eu³⁺. Li_0.3La_0.57Nd_0.05Ti_0.9P_0.05O₃ has the highest bulk conductivity of 4.31×10⁻⁴ S·cm⁻¹ and the highest total conductivity of 2.52×10⁻⁴ S·cm⁻¹ at room temperature in all prepared compositions. The compositions have low activation energies of about 24–30 kJ/mol in the temperature ranges of 298–523 K. SEM studies showed that the sample made by solid-state reaction has a sphere-like morphology and a rough particle with particle size of about 50 μm. The research results also indicated that the reaction temperature decreases and the electrochemical stabilities of the titanate-based perovskite-type solid solutions are improved by using RE³⁺ and P⁵⁺ replaced Ti⁴⁺ on B-site in the Li_3xLa_0.67−xTiO₃ parent.     

Effect of iso- and heterovalent additives on characteristics of highly transparent Nd(Yb):Y<Subscript>2</Subscript>O<Subscript>3</Subscript> ceramics

The possibility of synthesis and characteristics of highly transparent Y₂O₃ ceramics doped with Nd³⁺ and Yb³⁺ were studied. The ceramics crystal structure was disordered for the first time by simultaneously substituting Y³⁺ cations by Lu³⁺ or Sc³⁺ isovalent ions and Zr⁴⁺ heterovalent ions. The developed technique allowed synthesis of highly transparent Nd³⁺:Y₂O₃, Nd³⁺: Y₂O₃ + 6 mol % ZrO₂, Nd³⁺: (Lu_0.25Y_0.75)₂O₃ + 6 mol % ZrO₂, Nd³⁺:(Sc_0.25Y_0.75)₂O₃ + 6 mol % ZrO₂, and Yb³⁺:(Sc_0.25Y_0.75)₂O₃ + 6 mol % ZrO₂ ceramics with transmittance to 82.2%. It was shown that introduction of iso- and heterovalent additives Sc₂O₃, Lu₂O₃, and ZrO₂ into Nd³⁺:Y₂O₃ decreases average crystallite sizes to ∼1 μm and reduces the pore content, thus making it possible to produce pore-free ceramics. These additives broaden the spectral band of the ⁴ F _3/2 → ⁴ I _11/2 transition of the neodymium ion to 40 nm.     

Spectroscopy and self-frequency doubling of the 4F3/2?→?4I13/2 laser channel in the La2CaB10O19:Nd3+ bi-functional crystal

Nd_xLa_2-xCaB₁₀O₁₉ crystals with different Nd³⁺ concentrations were grown by the high-temperature flux method and oriented for frequency doubling of 1340 nm wavelength radiation. The room temperature spectroscopy (absorption, emission and lifetimes) of the ⁴ F _3/2 → ⁴ I _13/2 Nd³⁺ laser channel was investigated. We have clearly shown that two inequivalent Nd³⁺ centers in the La³⁺ and Ca²⁺ positions are responsible for the spectroscopic properties. Self-frequency doubling can be obtained from these two centers at 661.1 and 671.5 nm. PACS 42.55.f; 42.65.Ky     

Effect of Nd concentration on structural and optical properties of Nd:Y2O3 transparent ceramic

Y₂O₃ transparent ceramics with different Nd concentration (0.1-7.0at%) were fabricated using ZrO₂ as additive. All the samples exhibit high transparency over a broad spectral region. The elements (Y, O and Nd) are uniformly distributed in the ceramic body, and the average grain size increases with Nd content. Based on the absorption spectrum, the Judd-Ofelt intensity parameters are calculated (Ω₂=4.364×10⁻²⁰ cm², Ω₄=3.609×10⁻²⁰ cm² and Ω₆=2.919×10⁻²⁰ cm²). The absorption coefficients increase linearly with Nd³⁺ doping concentration. The absorption cross-section at 804 nm and stimulated emission cross-section at 1078 nm are calculated to be 1.54×10⁻²⁰ and 7.24×10⁻²⁰ cm², respectively. All the emission bands exhibit the highest emission intensities with 1.0at% Nd³⁺ ion content, while the lifetime decreases dramatically from 321.5 μs (0.1at% Nd) to 17.9 μs (7.0at% Nd). According to the emission spectra and measured lifetime, the optimum doping concentration of Nd³⁺ ion in Y₂O₃ transparent ceramic might be around 1.0at%.     

Luminescence of neodymium-doped yttria

Pulsed cathodoluminescence of Nd³⁺: Y₂O₃ nanopowders of the cubic and monoclinic phases and the ceramics synthesized from these nanopowders has been investigated in the spectral range 350–850 nm. It is found that the IR emission band of neodymium ions in the Nd³⁺: Y₂O₃ cubic phase is located at λ₁ ≈ 825 nm. When there is a monoclinic phase admixture, two additional luminescence bands of Nd³⁺ arise in the spectrum at λ₂ ≈ 750 nm and λ₃ ≈ 720 nm. The emission spectrum of all Nd³⁺: Y₂O₃ materials also contains a wide intrinsic band of yttrium oxide at λ ≈ 485 nm; however, the presence of neodymium decreases the intensity of this band and increases the its structurization. It is suggested that the structure of this band in Nd³⁺: Y₂O₃ materials is mainly determined by local absorption (self-absorption) of neodymium ions.     

Intense visible luminescence from Nd-doped yttrium oxysulfide

We report on a novel luminescent phenomenon in Y₂O₂S doped with Nd³⁺. After irradiation by a 261 nm ultraviolet (UV) light into the Y₂O₂S host lattice, the Nd³⁺-doped Y₂O₂S phosphor emits intense blue luminescence in the visible light region. Moreover, this blue luminescence can also be obtained by exciting directly into the Nd³⁺ energy absorption itself. XRD, photoluminescence, and fluorescence decay curve are used to characterize the synthesized phosphor. The spectroscopic data indicate that all the visible emission peaks are originated from the electrical transitions of Nd³⁺, and the strong luminescence of the Nd³⁺ is considered to be due to an efficient energy transfer from the Y₂O₂S host lattice to the Nd³⁺ in Y₂O₂S:Nd³⁺. The optimum concentration for the luminescence Nd³⁺ is determined to be 1 mol% of Y³⁺ in Y₂O₂S host. The critical energy transfer distance has been calculated by the concentration quenching and the possible luminescent process of this blue luminescence-emitting phosphor is also investigated.