Tm3+/Yb3+/Er3+共掺氟氧硅酸盐玻璃的上转换发光特性

利用熔融法制备了Tm3+/Yb3+/Er3+共掺氟氧硅酸盐玻璃.在980nm LD激发下,研究了Tm3+离子和Er3+离子之间的能量传递和Tm3+离子的上转换荧光,分析了Tm3+离子的上转换机理,发现蓝色上转换荧光是三光子过程对应于1 G4→3 H6的跃迁,而红色上转换荧光是双光子过程对应于1 G4→3 F4的跃迁.比较不同掺杂摩尔分数的样品的荧光强度,发现Tm3+离子的最佳掺杂摩尔分数为0.2%.     

Ligand hyperfine Yb3+ interaction in CsCaF3 and Cs2NaYF6 crystals

The operator, which determines the contribution of processes including the polarization of central ion core to the ligand hyperfine interaction (LHFI), has been obtained in the second quantization representation in the basis of partially nonorthogonal orbitals. The contributions of the impurity Yb³⁺ ion to the LHFI parameters have been also calculated in Cs₂NaYF₆ and CsCaF₃ crystals, which are determined by the mechanisms studied earlier. The single-particle orbital basis has been extended as compared to the previous work. There is a sufficiently good agreement with the experiment.     

Comparison of selected optical properties of oxyfluoride glass fibers doped with Er3+ and co-doped with Er3+ Yb3+

The method of manufacturing and spectroscopic evaluation of the Er³⁺ ions doped and Er³⁺–Yb³⁺co-doped SiO₂–Al₂O₃–Na₂CO₃–CaO–PbO–PbF₂ oxyfluoride glass fibers is presented in the paper. Both optically active elements erbium and ytterbium were introduced into the batch in the form of fluorides. The X-ray diffraction (XRD) technique was applied at each stage of fibers manufacturing in order to control an amorphous structure of the preforms and fibers. Optical studies of glass preforms and fibers (reflection/transmission, absorption, emission, and excited state absorption (ESA)) were directed to examine their suitability as fiber amplifiers at 1.55 μm band.     

Crystal field splittings and luminescence properties for Nd3+, Er3+ and Dy3+ in yttrium orthoaluminate (YAlO3)

This report contains information appropriate for a theoretical analysis of the optical spectra of triply ionized lanthanides in YAlO₃. Starting with the best-fit crystal field parameters, the crystal field splitting schemes, multiplet-to-multiplet line strengths, radiative lifetimes, branching ratios, line-to-line square matrix elements and g-factors for the triply ionized Nd, Er and Dy in YAlO₃ have been calculated. In this paper detailed discussions were made on the luminescence properties of the principal transitions of Nd-doped YAlO₃ emanating from the metastable ⁴F_{$\text{3}\text{2}$} state to Stark components of multiplets of the ground ⁴I_J term and compared to similar results of Y₃Al₅O₁₂ (YAG). The line-to-line branching ratios were calculated including J-mixing effects. In the calculations, only electric dipole transitions were considered because of odd-parity. The results predicted some interesting differences in the optical behavior of Nd³⁺ in these two host materials. It has been observed that there is a reasonable agreement between the theoretical data and those reported experimentally for YAlO₃ and YAG. The theoretical studies undertaken here were chosen to supplement or extend the optical data for these two host materials.     

Luminescence kinetics of LiNbO3:Yb3+-Er3+, LiNbO3:Er3+, and LiNbO3:Yb3+ crystals under selective excitations in the impurity subsystem

The results of investigations of luminescent radiations’ kinetic characteristics for LiNbO₃:Yb³⁺-Er³⁺, LiNbO₃:Er³⁺, and LiNbO₃:Yb³⁺ crystals under optical excitations at 532 nm and 1064 nm wavelengths are presented. The shapes and times of rise and damping of luminescent signals at 550 nm, 980 nm and 1555 nm wavelengths under selective excitations in the impurity subsystem of the investigated materials are determined. Comparison of the temporal characteristics of luminescent responses of LiNbO₃ crystals doped separately with Yb³⁺ and Er³⁺ ions with those of the LiNbO₃:Yb³⁺-Er³⁺ crystal allows identifying the contributions from different energy transfer processes of optical excitation taking place in the impurity subsystem of the material.     

Crystal field measurement for Tb3+ in gold

The crystal field parameters for 0.01 at.% Tb³⁺ in gold have been determined by gamma-ray anisotropy measurements as a function of magnetic field. The values of the parameters are X = 0.90 ± 0.01 and W = -0.19 ± 0.002 K.     

The sign of Fe3+OCr3+ superexchange determined from Fe57 hyperfine field measurements

The sign of the super-transferred hyperfine field at an impurity site is shown to depend on the sign of the impurity-host superexchange interaction. This fact is used to determine that the Fe³⁺OCr³⁺ superexchange in YCrO₃ is antiferromagnetic.     

Direct Sensitization Up-conversion Mechanism in Er3+:Yb3+ Co-doped Fluoride Materials

Up-conversion luminescence have been studied on Yb3+-Er3+ co-doped fluoride samples. Two infrared lasers with wavelength of 930 nm and 858 nm are carefully chosen as excitation sources. The experimental results suggest direct cooperation sensitization up-conversion rather than two-step sensitization up-conversion is responsible for the increased population of 2H11/2 (Er3+) and thus the increased green emission in the region 514～574 nm in Yb3+-Er3+ co-doped system.     

Er~(3+)浓度对Er~(3+)/Yb~(3+)共掺氟氧化物玻璃陶瓷上下转换发光的调控(英文)

在980nm激光激发下,Er3+/Yb3+共掺的发光材料既可以在可见光范围产生上转换发光,也可以在近红外波段产生下转换发光,二者存在竞争关系。本文利用熔融淬火法制备了一系列掺杂不同Er3+/Yb3+浓度的氟氧化物玻璃陶瓷,测量了样品在980 nm激光激发下的上转换及下转换发射光谱。研究发现,改变Er3+的掺杂浓度可以调控上下转换的发光强度。在此基础上,提出了上下转换发光的能量传递模型。本文的研究结果有利于该类材料在不同领域中的应用。     

Enhancement of upconversion intensity in Er3+ doped tellurite glass in presence of Yb3+

TeO₂–PbO glasses doped/codoped with Er³⁺/Er³⁺-Yb³⁺ ions have been fabricated by melting and quenching method. Efficient frequency upconversion emissions spanning from blue to red regions corresponding to the ²H_11/2, ⁴S_3/2→⁴I_15/2 and ⁴F_9/2→⁴I_15/2 transitions, respectively, upon excitation with 976 nm diode laser radiation have been observed. The variations observed in the intensity of whole upconversion emission spectra due to the presence of the Yb³⁺ ions are reported and discussed in detail.     

Er~(3+),Yb~(3+)共掺杂的NaYF_4荧光粉的制备及下转换发光研究

采用高温固相法合成了Er3+、Yb3+共掺杂的NaYF4荧光粉。XRD测量数据表明合成的样品为纯相。测量了样品的激发谱和发射谱,证明377 nm的紫外光通过量子剪裁的形式将能量传递给一个Yb3+,发射一个975 nm的红外光子,再从4F9/2能级跃迁到基态发射一个红外光子。测量了377 nm激发下,监测541 nm的发光寿命曲线,计算得到最大的量子效率为126.35%。通过监测Yb3+的975 nm的近红外发射,证明了Er3+的4F7/2和2H11/2能级通过下转换的形式将吸收的485 nm和519 nm的能量传递给Yb3+。这种将Er3+在可见光波段的多种光子能量传递给Yb3+发射975 nm的近红外光子的思想在以前的研究中从未被提出。     

Crystal field effect on the paramagnetic properties of Dy3+ ion in dysprosium gallium garnet

Magnetization and susceptibility measurements have been performed on single crystals of dysprosium gallium garnet along different axes. The isothermal magnetization curves in the temperature range 1.2K – 4.2K with applied fields up to 70 kOe are well interpreted using a crystal field hamiltonian appropriate for the D₂-symmetry of the rare earth sites. The lowest four levels in the ${}^6\text{H}{}_{\mathrm{<mtext>15</mtext><mtext>2</mtext>}}$ manifold calculated with our nine crystal field parameters are in agreement with both the absorption data of Grünberg et al. and the Raman data of Wadsack et al. The calculated g-factors confirm a strong quasi-planar type anisotropy.Between 1.5K and 15K the temperature dependance of the magnetic susceptibility is well account for with our crystal field calculation ; below 5K the Curie-Weiss law was added to take account of magnetic interactions between rare earth ions.     

氟化物对Er~(3+)/Yb~(3+)共掺的碲酸盐玻璃上转换和红外发光性能的影响

Er3+/Yb3+共掺的碲酸盐玻璃由于其良好的上转换发光性能而得到广泛的研究。本文将氟化物引入碲酸盐玻璃中,通过熔融法制备了量比为70TeO2-(30-x)ZnO-xZnF2-0.15Er2O3-1.5Yb2O3(x=0,5,10,15,20)的碲酸盐氧氟玻璃样品,并测试其热稳定性、拉曼光谱以及受激发射光谱。实验结果表明,随着氟化物含量的提高,Er3+离子的410,555,670 nm上转换发光和2~3μm波段中红外发光得到增强,并且红光提高强度比绿光和蓝光更明显。在分析了氟离子引入后对上转换与近中红外波段发光的内在影响机制发现:碲酸盐玻璃系统中的氟化物一方面促进能量传递过程中Er3+离子的双光子吸收,促进粒子跃迁至相应的高能级;另一方面,引入氟化物后的碲酸盐玻璃的最大能量声子态密度下降也是降低无辐射跃迁概率、提高上转换和中红外发射强度的重要原因。     

Study of the optical characteristics of TZLB glass activated by Er3+ and Yb3+ ions

The transmission spectra of glass based on tellurium oxide (TeO₂), of the TeO₂-ZnO-Li₂OBi₂O₃ composition (TZLB), which is highly stable to crystallization, have been measured. The concentration dependences of the luminescence (1.53 μm) intensity and kinetics of erbium ions under 975-nm excitation have been investigated. Based on the experimental results, a fundamental possibility of using TZLB glasses activated by Er³⁺ and Yb³⁺ ions for active elements of fiber and integrated optics is shown.     

Mesoporous silica-coated NaYF4:Yb3+, Er3+ particles for drug release

NaYF₄:Yb³⁺, Er³⁺ nanoparticles were successfully prepared by a polyol process using diethyleneglycol (DEG) as solvent. These NaYF₄:Yb³⁺, Er³⁺ nanoparticles can be coated with mesoporous silica using nonionic triblock copolymer EO₂₀PO₇₀EO₂₀ (P 123) as structure-directing agent and other materials. The composites can load ibuprofen and release the drug in the phosphate buffer solution (PBS). The composites were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), nitrogen absorption/desorption isotherms, fluorescence spectra, and UV/Vis absorption spectra, respectively. The composites have the mesoporous structure. In addition, the composites emit red fluorescence (from Er³⁺) under 980 nm near infrared laser excitation, which can be used as fluorescent probes in the drug-delivery system.     

Magnetic field effects on the fluorescence of Cr3+ in GdAlO3

The fluorescence spectrum of Cr³⁺ in GdAlO₃ has been examined at 4.2 K as a function of magnetic field up to 60 kG. The resulting splitting of the ²E → ⁴A₂ emission lines are explained in terms of a modified molecular field approximation, which incorporates the effect of the spin fluctuations. The exchange constant in the relaxed excited state is found to be 1.2 cm^-1, which differs from that reported from absorption data. It is suggested that the difference may be related to the Frank-Condon effect.     

Lu_(2)O_(3)∶Er^(3+)/Yb^(3+)荧光材料的上转换发光及其温度传感特性EI北大核心CSCD

采用CO_(2)激光区熔法制备了Lu_(2)O_(3)∶0.5%Er^(3+)/x%Yb^(3+)(x=1,3,5)上转换荧光材料。X射线衍射结果表明,所制备的Lu_(2)O_(3)∶Er^(3+)/Yb^(3+)荧光材料具有纯Lu_(2)O_(3)晶相。在980 nm激光激发下,样品发出明亮的上转换荧光。光谱测试结果表明,样品上转换荧光强度和荧光中绿光与红光比例随Yb^(3+)离子浓度改变,当Er^(3+)和Yb^(3+)离子浓度分别为0.5%和3%时,样品上转换荧光强度最强。通过荧光强度比(FIR)技术研究了样品Lu_(2)O_(3)∶0.5%Er^(3+)/3%Yb^(3+)在298~873 K温度范围内上转换荧光温度传感特性,在532.8 K时最大绝对灵敏度为0.0060 K^(-1),在298 K时最大相对灵敏度为0.0090 K^(-1)。结果表明,Lu_(2)O_(3)∶Er^(3+)/Yb^(3+)荧光材料非常适合用于宽温度范围荧光温度传感。     

高Yb~(3+)/Er~(3+)掺杂的磷基有源光纤材料的光谱性质

研究了Yb3+/Er3+共掺60P2O5-15BaO-10Al2O3-5ZnO-10R2O(R=Na,K)以P2O5为主体的磷基有源光纤材料的光谱性质,以及不同Yb3+/Er3+掺杂浓度对光谱性质的影响规律。当Er3+浓度为9.100×1019/cm3、Yb3+的掺杂浓度为5.407×1020/cm3、Yb3+/Er3+浓度比为6∶1时,玻璃样品在1 531 nm处的受激发射截面最大,为6.17×10-21cm2。同时,其荧光寿命为9.73 ms,荧光半高宽为53.16 nm,发射截面与半高宽的乘积为3.28×10-32m3,综合性能最佳。     

Vaaisible upconversion emission of Er3+-doped and Er3+/Yb3+-codoped LiInO2

Lithium-indium oxide is a high-density (5.9 g·cm⁻³), wide band-gap semiconductor with promising applications for scintillating detection of solar neutrinos as well as for efficient phosphorescence when doped with Er³⁺ or Sm³⁺ ions. In this report, we demonstrate visible upconversion emission of Er³⁺-doped LiInO₂ synthesized by a simple solid-state chemistry procedure and discuss mechanisms responsible for pumping the Er³⁺ ions to upper levels. Intense upconversion emission is observed in the green and red spectral regions under near-infrared excitation, and it is greatly enhanced by co-doping with Yb³⁺ ions. We also examined the upconversion intensity change as a function of temperature, and, consequently, possible applications of this material as a low-temperature sensor.