Sm:GdVO_4晶体的生长及光谱性能研究

应用中频感应提拉法生长出掺杂浓度为2%原子分数的Sm:GdVO4晶体,研究了室温下c轴方向Sm:GdVO4晶体的吸收和荧光光谱。通过J-O理论计算出强度参数(Ωt),同时计算了对应于4G5/2能级的自发跃迁几率、荧光分支比和辐射寿命。通过荧光光谱计算了对应于566、604和646nm三个发射峰对应的发射截面,结果表明,Sm:GdVO4在604nm的发射截面最大,是掺Sm:YAP在607nm处发射截面的4.4倍。

Growth and spectral properties of Er:Gd2SiO5 crystal

Er3+ -doped Gd2SiO5 (Er:GSO) single crystal with dimensions of circle divide 35 x 40 mm(3) has been grown by the Czochralski method. The absorption and fluorescence spectra of the Er:GSO crystal were measured at room temperature. The spectral parameters were calculated based on Judd-Ofelt theory, and the intensity parameters Omega(2), Omega(4) and Omega 6 are obtained to be 6.168 x 10(-20), 1.878 x 10(-20), and 1.255 x 10(-20) cm(2), respectively. The emission cross-section has been calculated by Fuechtbauer-Ladenbury formula. (c) 2007 Elsevier B.V. All rights reserved.

利用窄得-奥菲特理论研究Tm:Lu_2SiO_5晶体的光谱特性

采用丘克拉斯基(Czochralski)技术生长了掺铥硅酸镥(Tm∶Lu2SiO5,Tm∶LSO)晶体;测量了LSO晶体在室温下的非偏振吸收光谱和非偏振荧光光谱;利用窄得-奥菲特(Judd-Ofelt)理论计算了Tm∶LSO晶体的窄得-奥菲特强度参数、振子强度、自发辐射概率、辐射寿命、积分吸收截面和积分发射截面.Tm∶LSO晶体的强度参数为Ω2=9.1355×10-20cm2,Ω4=8.4103×10-20cm2,Ω6=1.5908×10-20cm2;Tm∶LSO晶体在1.9μm附近有明显的发射峰(3F4→3H6跃迁),相应的辐射寿命为2.03 ms,积分发射截面为5.81×10-18cm2,半峰全宽(FWHM)为250 nm.用Tm∶LSO晶体在77 K温度下实现了激光运转.利用792 nm的激光二极管(LD)作为抽运源,获得中心波长为1960 nm的激光输出,抽运阈值为2.13 kW/cm2.

Polarized spectral analysis of Ho3+ ions in biaxial YAlO3 crystal for 2 mu m lasers

An Ho3+-doped YAlO3 (Ho : YAP) single crystal has been grown by the Czochralski technique. The polarized absorption spectra, polarized fluorescence spectra and fluorescence decay curve of the crystal are measured at room temperature. The spectroscopic parameters are calculated based on Judd-Ofelt theory, and the effective phenomenological intensity parameters Omega(2,eff), Omega(4,eff) and Omega(6,eff) are obtained to be 2.89 x 10(-20), 2.92 x 10(-20) and 1.32 x 10(-20) cm(2), respectively. The room-temperature fluorescence lifetime of the Ho3+ 5I(7) -> I-5(8) transition is measured to be 8.1 ms. Values of the absorption and emission cross-sections with different polarizations are presented for the I-5(7) manifold, and the polarized gain cross-section curves are also provided and discussed.

Spectroscopic properties of anisotropic absorption in a neodymium-doped YAlO3 laser crystal

Absorption spectra of YAlO3:Nd for the three crystallographic axes are investigated at room temperature, The spectral strengths indicate that the absorption coefficient of YAlO3:Nd is anisotropic. The anisotropy of the local electric field acting on the rare-earth ion in a laser crystal is considered, An extended Judd-Ofelt theory is applied to calculate the absorption cross sections and oscillator strengths of the electric-dipole transitions in the different principal directions. Three groups of the phenomenological parameters are derived from a least-squares-fitting procedure. We also analyze theoretically the anisotropy of the optical absorption of YAlO3:Nd crystal in detail. (C) 1997 American Institute of Physics.

Concentration effects of Er3+ ion in YAG : Er laser crystals

Laser crystals of (Y1-xErx)(3)Al5O12, (YAG:Er) have been grown by the Czochralski method and the spectral properties have been studied for different Er3+ concentrations. The effects of various Er3+ concentrations on the structural distortions, luminescence quenching Of F-4(9/2), H-2(11/2), S-4(3/2) and red shift in laser wavelength have been discussed for the YAG:Er laser crystals. By using absorption spectra and Judd-Ofelt theory the experimental oscillator strengths, Omega(lambda), parameters and the excited state integrated absorption cross sections of Er3+ ion are reported and some variation regularities of these parameters have been observed. (C) 2000 Published by Elsevier Science S.A. All rights reserved.

Optical properties and frequency upconversion fluorescence in a Tm3+-doped alkali niobium tellurite glass

Optical spectroscopic properties of Tm3+-doped 60TeO(2)-10GeO(2)-10K(2)O-10Li(2)O-10Nb(2)O(5) glass are reported. The absorption spectra were obtained and radiative parameters were determined using the Judd-Ofelt theory. Characteristics of excited states were studied in two sets of experiments. Excitation at 360 nm originates a relatively narrow band emission at 450 nm attributed to transition D-1(2)-->F-3(4) of the Tm3+ ion with photon energy larger than the band-gap energy of the glass matrix. Excitation at 655 nm originates a frequency upconverted emission at 450 nm (D-1(2)-->F-3(4)) and emission at 790 nm (H-3(4)-->H-3(6)). The radiative lifetimes of levels D-1(2) and H-3(4) were measured and the differences between their experimental values and the theoretical predictions are understood as due to the contribution of energy transfer among Tm3+ ions. (C) 2003 American Institute of Physics.

Raman scattering, differential scanning calorimetry and Nd3+ spectroscopy in alkali niobium tellurite glasses

Alkali niobium tellurite glasses have been prepared and some of their properties measured by differential scanning calorimetry and Raman scattering. The vitreous domain was established in the pseudo ternary phases diagram for the system TeO2-Nb2O5-(0.5K(2)O-0.5Li(2)O). Raman scattering shows that for samples in the TeO2 rich part of the phase diagram the vitreous structure is composed essentially of (TeO4) units connected by the vertices, as in the alpha-TeO2 crystal. The addition of alkali and niobium oxides causes depolymerization to occur with structures composed essentially of (TeO3) and (NbO6) units. Samples with the composition (mol%) 80TeO(2)-10Nb(2)O(5)-5K(2)O-5Li(2)O, stable against crystallization, were prepared containing up to 10% mol Nd3+. The addition of this oxide increases the rigidity of the vitreous network shifting characteristic temperatures to higher temperatures. For the 10% Nd3+ sample amorphous phase separation is assumed to exist from the observation of two glass transition temperatures. Spectroscopic properties such as Judd-Ofelt Omega(lambda) intensity parameters, radiative emission probabilities, and induced emission cross sections were calculated. From these results and also from the emission quenching observed as a function of Nd3+ concentration, we suggest that these glasses could be utilized in optical amplifying devices. (C) 1999 Elsevier B.V. B.V. All rights reserved.

Dynamics of energy transfer and frequency upconversion in Tm3+ doped fluoroindate glass

The spectroscopic properties of Tm3+-doped fluoroindate glasses (FIG) were described by single wavelength pumping in the red region. The Judd-Ofelt (J-O) theory was used to obtain the quantum efficiency of the 4f-4f transitions and other spectroscopic parameters. The dynamics of the fluorescence was investigated and energy transfer (ET) processes among Tm3+ ions were studied. The results indicate that a two-step one-photon absorption process is responsible for the ultraviolet upconversion (UC) emissions, and dipole-dipole interaction provides the main contribution for ET rate is equal to the decay rate of noninteracting among active ions.

A polymeric europium complex with the ligand thiophene-2-carboxylic acid: Synthesis, structural and spectroscopic characterization

A polymeric complex [Eu(α-tpc)3(α-Htpc) 2]n and its characterization by single crystal X-ray and thermal analysis, infrared and photoluminescence spectroscopies are described. The compound crystallizes in the monoclinic Cc space group. The asymmetric unit is formed from a europium ion bonded to one carboxyl oxygen of five different thiophene carboxylic moieties. Three of these moieties are deprotonated and bridge between neighboring europium ions giving rise to an infinite polymer along the c axis. Besides the europium characteristic emission lines, the emission spectra show unambiguously the crystal size effect on the 5D0 → 7F0 transition. The complex thermal decomposition at 220 C leads to a stable luminescent complex in which the 5D0 → 7F4 transition reveals a monomeric characteristic. The Judd-Ofelt intensity parameters to the polymeric and the monomeric compound with the same ligand and coordination number were compared. © 2013 Published by Elsevier Ltd.

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Effect of the vanadium(V) concentration on the spectroscopic properties of nanosized europium-doped yttrium phosphates

Nanosized rare earth phosphovanadate phosphors (Y(P,V)O-4:Eu3+) have been prepared by applying the organic-inorganic polymeric precursors methodology. Luminescent powders with tetragonal structure and different vanadate concentrations (0%, 1%, 5%, 10%, 20%, 50%, and 100%, with regard to the phosphate content) were then obtained for evaluation of their structural and spectroscopic properties. The solids were characterized by scanning electron microscopy, X-ray diffractometry, vibrational spectroscopy (Raman and infrared), and electronic spectroscopy (emission, excitation, luminescence lifetimes, chromaticity, quantum efficiencies, and Judd-Ofelt intensity parameters). The solids exhibited very intense D-5(0) -> F-7(J) Eu3+ transitions, and it was possible to control the luminescent characteristics, such as excitation maximum, lifetime and emission colour, through the vanadium(V) concentration. The observed luminescent properties correlated to the characteristics of the chemical environments around the Eu3+ ions with respect to the composition of the phosphovanadates. The Eu3+ luminescence spectroscopy results indicated that the presence of larger vanadium(V) amounts in the phosphate host lattice led to more covalent and polarizable chemical environments. So, besides allowing for control of the luminescent properties of the solids, the variation in the vanadate concentration in the obtained YPO4:Eu3+ phosphors enabled the establishment of a strict correlation between the observable spectroscopic features and the chemical characteristics of the powders.

含纳米晶颗粒的Yb^3＋/Er^3＋共掺透明碲酸盐玻璃陶瓷的光谱性质研究

在组成为15Li2O-15Nb2O5-70TeO2-0.1Er2O3-0.4Yb2O3（%, 摩尔分数）的碲酸盐玻璃基础上, 采用两步热处理法制备了透明的含纳米晶颗粒碲酸盐玻璃陶瓷. 通过X射线衍射（XRD）测试表明, 玻璃陶瓷中的晶体颗粒组成为Yb6Te5O19.2或Er6Te5O19.2, 晶粒尺寸约为55 nm. 根据Judd-Ofelt理论计算了Er^3＋离子在基质玻璃和玻璃陶瓷中的光谱参数Ωt（t＝2, 4, 6）以及Er^3＋：4I15/2→4I13/2跃迁自发辐射几率, 根据McCumber

OH^-根对掺铒碲酸盐玻璃光谱性质的影响

制备了5种浓度下系列不同OH^-根含量的掺铒碲酸盐玻璃样品，测试了样品的红外吸收光谱，分析了在不同通氧除水时间下玻璃的红外吸收系数变化情况．测试了样品的吸收光谱，利用Judd-Ofelt理论计算了不同铒掺杂浓度和OH^-根含量样品的光谱参量Ωi（i=2，4，6）．根据McCumber理论计算了铒离子在1532nm处的吸收截面和Er^3＋：^4I13／2→^4I15/2跃迁峰值发射截面．测试了样品中Er^3＋：^4I13／2→^4I15/2跃迁对应的荧光光谱和^4I13／2能级荧光寿命，讨论了OH^-根对不

掺铥氟磷玻璃的结构、热学性质和光谱性质

制备了不同Al（PO3）3含量的掺铥系列氟磷玻璃，研究了其结构、热稳定性和光谱性质。随着Al（PO3）3含量的增加，该系列玻璃的密度降低，折射率增加，差热分析表明，转变温度、析晶起始温度、析晶峰温度和熔化温度增加。Al（PO3）3摩尔浓度在7％～9％时析晶稳定性最佳。采用归一化的拉曼光谱分析了材料的结构和声子状况，对于该系列氟磷玻璃，Al（PO3）3含量的增加不会影响声子能量，但使声子密度增大。测试了样品的吸收光谱，Tm^3＋的^3H6→^3F4在第三通信窗口的L波段有明显吸收。与在其它玻璃基质中相比，T