钕4,4′-二甲基-2,2′-联吡啶配合物液体激光介质的合成及其光学特性(英文)

合成并用元素分析、红外光谱法表征了一种4,4′-二甲基-2,2′-联吡啶五氟丙酸钕配合物—Nd(C2F5COO)3·Dmbp(Dmbp:4,4′-二甲基-2,2′-联吡啶).将该配合物溶解在N,N-二甲基甲酰胺中获得了液体介质,依据液体介质的吸收和荧光光谱,通过Judd-Ofelt理论计算获得了钕离子的谱线强度参数(Ω2,Ω4,Ω6)和受激发射截面.计算得到该配合物中钕离子4F3/2→4I11/2跃迁的受激发射截面为5.2×10-20 cm2,表明该钕配合物在液体基质中具有较好的发光特性.通过荧光发射光谱分析可知,Nd(C2F5COO)3·Dmbp将是一种有前途的光学增益材料.     

四磷酸钕锂晶体荧光弱猝灭现象的研究

五磷酸钕(Nd PP)的荧光弱猝灭现象已经研究得很详细了[1-3].对于四磷酸钕锂(LNP)晶体,至今尚缺乏这方面的研究.LNP的猝灭机制并不十分清楚.本文通过实验与分析指出,LNP的猝灭机制是4F3/2→、4I15/2和4I9/2→4I15/2的交叉弛豫,并有频率约200cm-1的声子参与.一、实 验 四磷酸钕锂分子式为LiNdP4Q12简写为LNP.为了观察钕荧光的浓度猝灭和温度效应,我们用钇稀释钕,生长了各种浓度的 LiNdx·Y1-xP4O12晶体(简写LNP相似文献   

掺钕TeO_2-Al_2O_3-Cs_2O玻璃的Judd-Ofelt理论分析与光谱特性

采用高温熔融法制备了组分为80TeO2-10Al2O3-10Cs2O-xNd2O3(x=0,0.5,1.0)(mol%)的掺钕碲酸盐玻璃,测试了玻璃样品的折射率、吸收光谱、荧光光谱和荧光寿命曲线.利用Judd-Ofelt理论计算得到光谱强度参数Ωλ(λ=2,4,6),Nd3+从4F3/2能级到4IJ(J=9/2、11/2、13/2、15/2)能级跃迁的荧光有效线宽Δλeff,4F3/2能级跃迁几率AJ,荧光分支比β,相应的荧光寿命τrad和量子效率η及受激发射截面σemi.在该碲酸盐体系中,Nd3+离子掺杂浓度为0.5mol%时,样品在1 060nm波长处的σemi·τmeas为6.21×10-24cm2·s,荧光有效线宽为31.4nm,量子效率达到89%.光谱特性对比分析结果表明,该掺钕碲酸盐玻璃是一种性能优良的固体激光材料.     

掺钕BGO单晶的光谱研究

本文详细分析研究了掺钕BGO单晶的光谱特性.测量了Nd(3+)离子在BGO单晶中的吸收谱、荧光谱(4F3/2→4I9/2、11/2、13/2)及荧光寿命,并研究了荧光谱的温度效应.计算了跃迁几率、发射截面、分支比和Ω2、4、6等光谱参数,和YAG:Nd3+作了比较.     

掺钕镉铝硅酸盐玻璃的Judd-Ofelt理论分析与光谱特性

以掺杂光子晶体光纤为介质的光纤激光器一直受到科研工作者的广泛关注,应用于光子晶体光纤纤芯的掺稀土元素玻璃的制备成为研制掺杂光子晶体光纤的关键问题。利用高温熔融工艺制备钕离子掺杂的40SiO_2-14Al_2O_3-(40-x)CdO-2Li2O-2K2O-2Na_2O-xNd_2O_3(x=0.07,0.14,0.21,0.35,0.42,0.56mol)重金属硅酸盐玻璃系统,测试了其吸收光谱和荧光光谱。采用Judd-Ofelt理论,计算了玻璃样品的强度参数Ωt(t=2,4,6)以及钕离子的自发辐射概率、荧光分支比、荧光辐射寿命等参数。利用测得的荧光光谱计算了钕离子能级跃迁4 F3/2→4 I11/2的受激发射截面及荧光有效线宽。结果表明:当掺Nd_2O_3的摩尔分数为0.42时,制备的镉铝重金属硅酸盐玻璃具有较大的受激发射截面和比较宽的荧光有效线宽,且与相关文献中的钕离子掺杂玻璃相比,具有良好的激光性能和增益性能,有望在研制掺杂光子晶体光纤中得到应用。     

稀土钕-丙烯酸-草酸配合物的合成、表征及荧光性能

合成了钕-草酸-丙烯酸三元固体配合物。利用元素分析、红外光谱(FT-IR)、紫外-可见光谱(UV-Vis)、热重分析(TGA)和荧光光谱等手段研究了配合物的结构和性质。结果表明配合物的组成为[Nd(OOC—COO)(CH2CH—COO)].3H2O,热分析结果表明该配合物具有较好的热稳定性。荧光光谱表明配合物都具有较好的荧光特性,且发射谱线很窄,主发射峰为钕离子的4G5/2 2G7/2-4I9/2跃迁,表明合成的新型稀土配合物可用作光致发光材料。     

掺钕锂铝硅玻璃陶瓷制备和发光性能研究

采用传统熔融及退火技术,引入合适的添加剂于相对低温下成功制备出掺钕锂铝硅玻璃,通过控制成核和析晶工艺制备出锂铝硅玻璃陶瓷。采用差热分析、X射线衍射、扫描电镜、紫外可见近红外分光光度计和荧光光谱仪对材料进行表征。三个发光谱带中心波长位于890 nm,1065 nm和1330 nm处,分别对应于4F3/2→4I9/2,4F3/2→4I11/2和4F3/2→4I13/2跃迁。玻璃陶瓷晶相及晶粒大小对Nd3 离子发光性能影响很大。当Nd3 离子进入晶粒尺寸为10~20 nm的β--锂霞石固溶体时,发光强度与基质玻璃相比明显增强,在1065 nm处的受激发射截面iσn达1.931×10-21cm2,比基质玻璃受激发射截面提高了约8%。当β--锂霞石固溶体晶粒尺寸接近可见光波长时钕离子发生荧光猝灭。而当β--锂霞石固溶体晶型转变为β--黝辉石固溶体时,荧光猝灭消失。     

全氟羧酸钕2,2’-联吡啶配合物的合成及其光学特性

合成了一系列全氟羧酸钕2,2’-联吡啶配合物:Nd(CF3COO)3.Dipy,Nd(C2F5COO)3.Dipy和Nd(C3F7COO)3.Dipy,并通过红外光谱、元素分析、热分析、紫外可见近红外吸收光谱和荧光光谱对其进行了表征。配合物的分解温度都高于260℃,最大失重温度超过340℃,说明它们具有良好的热稳定性。全氟羧酸的碳链长度和钕离子配位结构的差异,引起配合物的吸收跃迁强度的变化。根据紫外可见近红外吸收图谱,计算获得了Judd-Ofelt参数和受激辐射跃迁特性。配合物的受激发射面积分别为:3.63×10-20,2.36×10-20和1.49×10-20 cm2,可以和文献报道的无机材料媲美,它们将是非常有潜力的液体激光介质。     

羧酸类钕(Ⅲ)配合物的合成、热稳定性和荧光性能研究

为了开发稀土有机配合物作为激光工作物质,分别以均苯三甲酸(H3BTC)、苯六甲酸(H6MTA)和1,2,3,4,5,6-环己六甲酸(H6CCA)为配体合成了三种Nd(Ⅲ)的二元发光配合物。通过元素分析、等离子体原子发射光谱和红外光谱对其化学组成进行了结构表征,确定其化学结构依次为Nd(BTC)·4H2O,Nd2(MTA)·6H2O和Nd2(CCA)·4H2O,并对其热稳定性和荧光性能进行了分析测试。三种配合物的发射谱均有三个带状谱带,位于近红外区,其对应于Nd(Ⅲ)离子的特征跃迁4F3/2→4I9/2,4F3/2→4I11/2和4F3/2→4I13/2。结果表明,羧酸类钕(Ⅲ)配合物在近红外区具有明显的特征发射,具有良好的热稳定性和较好的发光性能,可以作为潜在的激光介质。     

荧光猝灭法测定茶叶中的钐和钕

在pH为3.20~3.40的弱酸性介质中,稀土金属元素钐(Ш)与钕(Ш)均能使刚果红的荧光显著猝灭。实验表明:刚果红的最大发射波长(λem)为419nm,在钐(Ш)和钕(Ш)的存在下,刚果红荧光猝灭程度(ΔF)与钐(Ш)和钕(Ш)的浓度呈线性关系。钐(Ш)和钕(Ш)的检出限分别为0.0826#g/mL和0.1088#g/mL,线性范围为0.004~2.8mg/mL和0.004~1.6mg/mL。文中优化了反应条件的影响,据此发展了以刚果红为荧光探针的灵敏、简便、快速测定钐(Ш)与钕(Ш)的新方法。将方法用于茶叶中钐(Ш)与钕(Ш)含量的快速测定,结果满意。     

Comparison of the Absorption Spectra of Nd3+ Ions in the NdFe3(BO3)4, Nd0.5Gd0.5Fe3(BO3)4, and Ho0.75Nd0.25Fe3(BO3)4 Crystals

Physics of the Solid State - The polarized optical absorption spectra in the region of a series of the f–f  transitions of Nd3+ ions in the Ho0.75Nd0.25Fe3(BO3)4,...     

Spectroscope studies of YAlO_3: (Lu~(3 )Nd~(3 ))

An increase of the Nd~(3 ) doping concentration and an enhancement of the laser induced fluorescence in the single crystal of YAlO_3: (Lu~(3 ), Nd~(3 )) have been observed and are attributed to the size compensation effect. The low temperature (4.2K) fluorescence spectra indicate that the structure of the sharp lines arising from the radiative transitions of Nd~(3 ) ions is not changed by the existence of Lu~(3 ) ions, but the emission lines are inhomogeneously more broadened. Besides, it has been observed that the fluorescence due to the radiative transition from the Stark's sublevel R_2 of the metastable level ~4F_(3/2) to the sublevels Y_1 of the manifold ~4I_(11/2) decreases with decreasing temperature and the fluorescence arising from the transitions R_1→Y_1 is relatively increased. The experimental fact is qualitatively interpreted.     

Intracavity frequency-doubled diode-pumped Nd : LaSc3(BO3)4 lasers

 An intracavity frequency-doubled 10%Nd : LaSc₃(BO₃)₄ (Nd : LSB) laser was investigated in different resonator configurations and in different operation modes under continuous wave (cw) and quasi-cw laser-diode pumping. With a Cr⁴⁺ : YAG passive modulator and a KTP crystal the second-harmonic output power at 531 nm amounted to 190 mW in Q-switched TEM₀₀ mode at 750 mW of pump power. In a sandwich resonator, when all the optical elements were in direct contact with each other, 0.8 W of green output power was obtained in cw mode under 2.7 W of pump power with a slope efficiency of 44%. In the same setup under fiber-coupled diode-laser array pumping (5.6 W of incident power), 1.2 W of green output power was achieved in cw mode and 1.4 W in quasi-cw mode. Received: 30 April 1996/Revised version: 1 July 1996     

High-power diode-pumped picosecond Nd(3+):YVO(4) laser

A diode-pumped Nd(3+):YVO(4) laser passively mode locked by a nonlinear mirror based on second-harmonic generation has been developed. Pumping with a fiber-coupled 10-W diode array, we generated nearly diffraction limited, linearly polarized 11-ps pulses at 1064nm, with average power of 2.7 W at a 150-MHz repetition rate. Pulses as short as 7.9 ps were measured with reduced output power (1.35 W) by optimal focusing in the nonlinear crystal.     

900-nm Nd:Ti:LiNbO(3) waveguide laser

We report what is to our knowledge the first laser operation of Nd(3+) -doped LiNbO(3) near 900 nm. An absorbed power threshold of 26 mW was obtained when the device was pumped at 814 nm. The design of the waveguide geometry to favor laser operation at this wavelength is demonstrated.     

Low temperature properties of (La,Nd)Sn3 alloys

Dilute (La_1–x Nd _x )Sn₃ alloys with 0.01<x<0.15 are characterized by determination of the superconducting transition temperatureT _c as well as low temperature measurements of the specific heat and inelastic neutron scattering. As an important result of these experiments we found that the Nd impurities in LaSn₃ exist as stable trivalent ions, in contrast to all other light rare earths. In addition, specific heat and neutron scattering results revealed the scheme of crystal field (CF) levels of Nd³⁺.Using this level scheme, the concentration dependence of the superconducting transition temperature,T _c (x), could be quantitatively fitted up tox9 at % by the theory of Keller and Fulde [J. Low. Temp. Phys.4, 289 (1971)]. From the relatively high initial slope ofT _c (x) we inferred that — besides isotropic spin exchange — other pair-breaking processes are important.In contrast toT _c (x), the reduced specific heat jumpsC/C ₀ as a function ofT _c /T _c0 (whereT _c0 andC ₀ refer to LaSn₃) were found to lie considerably below the theoretical curve for isolated Nd³⁺ ions. This is explained by Nd—Nd interactions resulting in a mean Zeeman splitting (<k _B T _c ) of the CF ground state, which could be directly observed in the form of broadened Schottky humps in the normal state specific heats.     

Spectroscopic investigation of rare-earth chromium borates RCr3(BO3)4 (R = Nd, Sm)

The optical absorption spectra of single crystals of neodymium and samarium chromium borates are studied. A magnetic phase transition in NdCr₃(BO₃)₄ (at T _c = 8 ± 1 K) and SmCr₃(BO₃)₄ (at T _c = 5 ± 1 K) is observed. The effective magnetic field acting on the Nd³⁺ ion from the side of the ordered magnetic subsystem of chromium is estimated.     

New green self-frequency-doubling diode-pumped Nd:Ca4GdO(BO3)3 laser

3+ :Ca₄GdO(BO₃)₃ (Nd:GdCOB). 21 mW of green cw laser emission for an absorbed pump power of 820 mW were achieved under laser diode-pumping. 64 mW of green cw laser output were obtained with 1 W of absorbed pump power under titanium-sapphire pumping. Its availability in large-size crystals with good optical quality makes Nd:GdCOB a true challenger to the best SFD laser crystal reported so far: Nd:YAl₃(BO₃)₄ (Nd:YAB or NYAB). Received: 2 March 1998/Revised version: 20 May 1998     

Role of Nd/Ba disorder on the penetration depth of Nd(1+x)Ba(2-x)Cu(3)O(7-delta) thin films

We report on a study on the effect of Nd/Ba disorder on the ab-plane penetration depth of epitaxial Nd(1+x)Ba(2-x)Cu(3)O(7-delta) thin films. While in stoichiometric samples lambda(T) at low temperature is linear, Nd-rich films exhibit a quadratic law. For low Nd excess (x<0.04), a satisfying fit is obtained using the "dirty" d-wave model assuming that Nd ions at Ba sites act as strong scattering centers. At high x (x>0.15) the data are explained if Nd/Ba disorder becomes less effective as a source of scattering. The effect of localization has been discussed to account for the experimental results.