Er3+/Yb3+共掺Bi2O3-GeO2-Na2O玻璃的上转换发光

研究了不同Er3 /Yb3 掺杂比46Bi2O3-44GeO2-10Na2O(B46G44N10)(摩尔分数)玻璃的吸收光谱、红外吸收谱和上转换光谱性质,分析了玻璃中Yb3 敏化Er3 的上转换发光机制。测试了Er3 离子在不同Yb3 浓度下玻璃中的上转换荧光强度,得到最佳的掺杂质量比Er3 ∶Yb3 =1∶6。计算了在980 nm激发下Er2O3质量分数为0.5%和Yb2O3质量分数为3.0%的Er3 /Yb3 共掺B46G44N10玻璃的绿光上转换效率为2.27×10-4。比较了不同基质材料玻璃的上转换效率,结果表明B46G44N10玻璃是一种良好的上转换基质材料。     

Er3+单掺和Er3+/ Yb3+共掺碲钨酸盐玻璃光谱性能

制备了Er3 + 单掺和Er3 + /Yb3 + 共掺碲钨酸盐玻璃 ,测量了Er3 + 在玻璃中的吸收光谱和 970nmLD激发下的荧光光谱和荧光寿命 ,计算了Er3 + 离子 1 5 μm波段的吸收和发射截面 ,研究了其荧光强度和发射带宽与掺Yb3 + 浓度间的关系。结果表明 ,共掺Yb3 + 可明显提高Er3 + 离子 1 5 μm荧光发射强度 ,并有利于提高其发射带宽。实验所得最佳掺Yb3 + 离子浓度为 3 6 6× 10 2 0 ions/cm3 ,Er3 + 离子 1 5 μm发射最大FWHM值为 81nm。     

Upconversion fluorescence modulation of CaTiO3:Yb3+/ Er3+ nanocubes via Zn2+ introduction

rials, CaTiO3:Yb3+/Er3+/Zn2+ nanocubes with uniform size were prepared by solvothermal method in this paper. They were respectively characterized by X-ray diffractometer (XRD), scanning electron microscope (SEM), photoluminescence (PL) spectroscopy and their fluorescence lifetimes. The results show that the average size of the nanocubes is about 550 nm×650 nm×850 nm with good upconversion luminescence (UCL) properties. Under 980 nm laser excitation, the effects of the ratio between activator Er3+ and sensitizer Yb3+ and Zn2+ doping on the upconversion fluorescence properties were investigated, and the optimal ion ratio was obtained. The results of steady-state spectra show that the strongest fluorescence intensity of CaTiO3:Yb3+/Er3+ was obtained with the addition of 10 mol% Zn2+ at a Yb3+/Er3+ molar doping ratio of 3:0.3, which was attributed to the crystal field asymmetry generated by the introduction of Zn2+ ions. The energy transfer and upconversion mechanism between Yb3+ and Er3+ ions in CaTiO3 nanocubes were investigated by analyzing the upconversion fluorescence kinetics.     

Yb3+对掺铒碲酸盐玻璃红外和上转换发光的影响

研制了Er3+/Yb3+共掺TeO2-ZnO-La2O3玻璃,测试了Er3+离子的吸收谱、荧光谱和上转换发光谱,系统研究了975 nm抽运下Yb3+离子对于Er3+离子1.5 μm波段荧光性能及其上转换发光性能的影响.结果表明,随着碲酸盐玻璃中Yb2Os含量的增加,Yb3+离子对Er3+离子的能量传递增强,Er3+离子1.5 μm波段的荧光强度和上转换发光强度相应增大,但后者相对于前者增加更为迅速.通过对粒子数速率方程的理论模拟,计算结果与实验测量结果较为一致,表明Er3+/Yb3+共掺碲酸盐玻璃是一种优良的潜在上转换激光器增益介质.对上转换发光分析表明,强烈的绿光和红光激发是基于双光子的吸收过程.     

Anomalous Raman Scattering of Colloidal Yb3+,Er3+ Codoped NaYF4 Nanophosphors and Dynamic Probing of the Upconversion Luminescence

Size‐dependent Raman spectra of the hexagonal (β)‐phase Yb³⁺,Er³⁺ codoped NaYF₄ nanophosphors and dynamic probing of the upconversion luminescence (UCL) are reported. Raman scattering results show the normal red shifts of Raman peaks but anomalous line narrowing with decreasing the particle sizes. The phonon confinement effects are believed to be dominated by the surface vibrational energies in affecting UCL. Dynamic decay data are then applied to quantitatively verify the surface effects and size‐dependent UCL. Dynamic probing is shown to be an efficient tool to both qualitatively and quantitatively characterize the upconversion nanophorphors (UCNPs) that have no “quantum efficiency.” The findings are relevant to the engineering of the nanostructures of the UCNPs for the applications of the bioimaging and photodynamic therapy.     

Er3+/Yb3+共掺光纤激光器中能量上转换的抑制

通过对掺Er^3 和Er^3 /Yb^3 共掺光纤激光器的输出功率进行数值模拟发现：高浓度的Er^3 /Yb^3 共掺光纤激光器的最大量子转换效率比同等浓度下的掺Er^3 光纤激光器的最大量子转换效率高出一倍。说明由于Yb^3 的加入，Er^3 /Yb^3 共掺光纤激光器有效地抑制了能量上转换，提高了受激转换效率。     

Er3+/Yb3+共掺碲酸盐玻璃的上转换低温特性研究

研究了低温下Er3+/Vb3+共掺碲酸盐玻璃在975 nm激光激发下的上转换光谱与温度的关系.通过上转换光谱测量观察到3处上转换荧光,它们依次为529 nm(2H11/2→4I15/2),546 nm(4S3/2→4I15/2)和669 nm(4F9/2→4I15/2),上转换绿光(546 nm)和红光(669 nm)荧光强度在80 K左右达到了最大值,与300 K温度下相比分别提高了2.198和1.556倍.而529 nm上转换绿光强度随着温度的降低逐渐减弱,直至消失.研究了4S3/2能级和2H11/2能级之间的粒子数分布与温度的关系,并通过理论模型拟合了实验测量的4S3/2能级和2H11/2能级之间的粒子数分布,测量了8～300 K温度范围下,4Sa/2能级和4F9/2的寿命和温度的变化关系以及通过高斯拟合研究了4S3/2能级和2H11/2能级Stark分裂与温度的关系.     

Gd_2O_3:Yb~(3+),Er~(3+)上转换纳米纤维的制备与表征

采用溶胶-凝胶法与静电纺丝技术相结合制备了PVA/[Gd(NO3)3+Yb(NO3)3+Er(NO3)3]复合纳米纤维,将其进行热处理,得到Gd2O3:Yb3+,Er3+上转换纳米纤维.采用XRD、SEM、TG-DTA、FTIR和荧光光谱对样品进行了表征.结果表明:复合纳米纤维为无定型,Gd2O3:Yb3+,Er3+上转换纳米纤维属于体心立方晶系,空间群为Ia3.复合纳米纤维的平均直径约为140nm,经过600℃焙烧后,获得了直径约60nm的Gd2O3:Yb3+,Er3+上转换纳米纤维.当焙烧温度高于600℃时,复合纳米纤维中水分、有机物和硝酸盐分解挥发完毕,样品不再失重,总失重率为81%.复合纳米纤维的红外光谱与纯PVA的红外光谱一致,600℃以上时,生成了Gd2O3:Yb3+,Er3+上转换纳米纤维.该纤维在980nm激光激发下发射出中心波长为522nm、560nm的绿色和659nm的红色上转换荧光,对应于Er3+离子的2H11/2/4S3/2→4Il5/2跃迁和4F9/2→4Il5/2跃迁.在Gd2O3:Yb3+,Er3+上转换纳米纤维形成过程中,PVA分子起到了导向模板作用.PVA/[Gd(NO3)3+Yb(NO3)3+Er(NO3)3]复合纳米纤维在热处理过程中,PVA分解挥发,稀土硝酸盐分解并氧化生成Gd2O3:Yb3+,Er3+纳米颗粒,这些纳米颗粒相互联结起来形成了Gd2O3:Yb3+,Er3+上转换纳米纤维.     

Synthesis of Hexagonal Yb3+,Er3+‐Doped NaYF4 Nanocrystals at Low Temperature

Nanocrystals of NaYF₄ doped with Yb³⁺ and Er³⁺ are synthesized in oleylamine using Y₂(CO₃)₃, Yb₂(CO₃)₃, Er₂(CO₃)₃, Na₂CO₃, and NH₄F as precursors. In contrast to other starting materials normally used for such syntheses, these precursors react even at room temperature to form hexagonal‐phase (β‐phase) NaYF₄:Er,Yb nanoparticles. Cubic‐phase (α‐phase) NaYF₄:Yb,Er particles are formed only at elevated temperatures (>250 °C). The formation of the cubic phase at high temperatures can be suppressed by replacing pure oleylamine with oleic acid/oleylamine mixtures. Under optimized reaction conditions, particles with an average particle size of about 7 nm are generated in 84% yield. Heat treatment (30 min, 280 °C) of the particles significantly increases the luminescence efficiency. A transparent solution of the heat‐treated, nanometer‐sized phosphor in toluene shows intense visible light emission upon excitation in the near infrared.     

Synthesis of Hexagonal‐Phase NaYF4:Yb,Er and NaYF4:Yb,Tm Nanocrystals with Efficient Up‐Conversion Fluorescence

IR‐to‐visible up‐conversion fluorescent nanocrystals of hexagonal‐phase NaYF₄:20 %Yb,2 %Er and NaYF₄:20 %Yb,2 %Tm have been synthesized by decomposition of multiprecursors of CF₃COONa, (CF₃COO)₃Y, (CF₃COO)₃Yb, and (CF₃COO)₃Er/(CF₃COO)₃Tm in oleylamine at 330 °C. The average particle size is 10.5 ± 0.7 nm (from random measurements of 200 particles from five transmission electron microscopy images) and 11.1 ± 1.3 nm (from dynamic‐light‐scattering measurements). The up‐conversion fluorescence intensity of the hexagonal nanocrystals in this work is much higher than that of other cubic‐phase NaYF₄:Yb,Er nanocrystals, including the ones in this work (by a factor of 7.5). Mechanisms for nucleation and growth of the hexagonal‐phase nanoparticles are proposed. These nanocrystals are easily dispersed in organic solvents, producing a transparent colloidal solution. The hydrophobic surfaces of the particles are made hydrophilic using a bipolar surfactant. These nanoparticles and their dispersions in various media have potential applications in optical nanodevices and bioprobes.     

用于波导放大器的Er3+/Yb3+共掺磷酸盐玻璃的性能研究

通过优化熔融条件和玻璃组份,成功开发出一种新的Er3+/Yb3+ 共掺磷酸盐玻璃,其在沸水和熔盐中均表现出很好的化学稳定性.通过分析室温下Er3+/Yb3+ 共掺磷酸盐玻璃的吸收光谱,计算得到了Er3+ 离子在波长1533 nm处的峰值发射截面和杜得奥菲而特强度参数;其中Er3+ 离子在波长1533 nm 处的峰值发射截面为0 72×10-20 cm2,大于Schott的IOG1玻璃中Er3+离子的峰值发射截面0 67×10-20 cm2.通过改变离子交换的条件,获得了1 55μm单模光波导的制作条件;制作的波导传输损耗均小于1 dB/cm.初步的离子交换实验表明,Er3+/Yb3+共掺磷酸盐玻璃WM4完全适合波导放大器的制作.     

双包层Er3+/Yb3+共掺光纤放大器

详细描述了双包层Er^3＋／Yb^3＋共掺光纤放大器的基本原理和基本结构,介绍了此类光纤放大器在提高输出功率、提高增益、降低噪声及增益平坦等方面的研究进展,并报道了最新的实验结果：采用双包层Er^3＋／Yb^3＋共掺光纤放大器,实现了中心波长位于1561nm、3dB带宽为8nm、输出功率达1．16w超荧光输出,光光转换效率可达32％。     

Large Upconversion Enhancement in the “Islands” Au–Ag Alloy/NaYF4: Yb3+, Tm3+/Er3+ Composite Films,and Fingerprint Identification

The surface plasmon (SP) modulation is a promised way to highly improve the strength of upconversion luminescence (UCL) and expand its applications. In this work, the “islands” Au–Ag alloy film is prepared by an organic removal template method and explored to improve the UCL of NaYF₄: Yb3+, Tm³⁺/Er³⁺. After the optimization of Au–Ag molar ratio (Au_1.25–Ag_0.625) and the size of NaYF₄ nanoparticles (NPs, ≈7 nm), an optimum enhancement as high as 180 folds is obtained (by reflection measurement) for the overall UCL intensity of Tm³⁺. Systematic studies indicate that the UCL enhancement factor (EF) increases with the increased size of metal NPs and the increase of diffuse reflection, with the decreased size of NaYF₄ NPs, with the decreased power density of excitation light and with improving order of multiphoton populating. The total decay rate varies only ranging of about 20% while EF changes significantly. All the facts above indicate that the UCL enhancement mainly originates from coupling of SP with the excitation electromagnetic field. Furthermore, the fingerprint identification based on SP‐enhanced UCL is realized in the metal/UC system, which provides a novel insight for the application of the metal/UC device.     

Er3+/Yb3+共掺光波导激光玻璃的光谱特性研究

制备了以P2O5,Nb2O5,Na2O,Ga2O3为基质的Er3+/Yb3+共掺铌磷酸盐玻璃样品,差热分析显示其转变温度高达560℃,表明PNNG玻璃具有较高的热稳定性和离子交换特性.应用Judd-Ofelt理论计算了PNNG玻璃中Er3+离子的自发跃迁几率、荧光分支比和辐射寿命等光谱参量.同时利用McCumber原理研究了PNNG玻璃在1.53 μm处的受激发射截面和带宽,其值分别为σe(λ)=6.9×10-21cm2,△λ=55.7nm,结果表明重金属氧化物Nb2O5的加入提高了PNNG玻璃的折射率,从而提高了玻璃的发射截面和带宽,改善了光学特性.     

掺Er3+及Er3+/Yb3+石英有源光纤的制作与应用

综述了掺Er^3 及Er^3 /Yb^3 石英有源光纤的材料特性，制作工艺及应用，并展望了这两种光纤材料的发展前景。     

Influence of Input Pulse Durations on Properties of Er^3＋/Yb^3＋ Co-doped DCFA

Based on propagation-rate equations, the influence of different input pulse durations on the properties of Er^3＋/Yb^3＋ co-doped double-clad fiber amplifier at dynamic equilibrium was analyzed. The change characteristic of output power sag with pulse duration and repetition rate was shown. Whether single or multichannel input pulses are amplified, the shorter the input pulse duration is, the smaller the power sags of output pulse will be. At low repetition rate, upper gain values（Gupper） of gain swing are almost the same for different input pulse durations, which tend to the small signal gain, but lower gain value（Glower） of short input pulse is larger than that of long input pulse. At highrepetition rate, lower gain value（Glower） approaches to upper gain value（Glower）.     

Spectral properties and energy transfer in Er3+/Yb3+ co-doped LiYF4 crystal

Laser crystals of LiYF4 (LYF) singly doped with Er3+ in 2.0% and co-doped with Er3+/Yb3+ in about 2.0%/1.0% molar fraction in the raw composition are grown by a vertical Bridgman method. X-ray diffraction (XRD), absorption spectra, fluorescence spectra and decay curves are measured to investigate the structural and luminescent properties of the crystals. Compared with the Er3+ singly doped sample, obviously enhanced emission at 1.5 μm wavelength and green and red up-conversion emissions from Er3+/Yb3+ co-doped crystal are observed under the excitation of 980 nm laser diode. Meanwhile, the emission at 2.7 μm wavelength from Er3+ singly doped crystal is reduced. The fluorescence decay time ranging from 18.60 ms for Er3+ singly doped crystal to 23.01 ms for Er3+/Yb3+ co-doped crystal depends on the ionic concentration. The luminescent mechanisms for the Er3+/Yb3+ co-doped crystals are analyzed, and the possible energy transfer processes from Yb3+ to Er3+ are proposed.     

铒镱共掺波导放大器的增益特性

在忽略放大自发辐射(ASE)及均匀掺杂和稳态的情况下,在初始能量转移效率的基础上从速率方程和传输方程出发,推导出了用于分析铒镱共掺波导放大器(EYCDWA)的新公式.利用这些公式分析了泵浦光功率、信号光功率、掺杂浓度、波导长度对放大器增益特性的影响,并与单掺铒波导放大器(EDWA)进行了比较,得到了一些具有实用价值的模拟结果.     

Ho3+/Yb3+/Ce3+三掺钽酸锂上转换绿光的研究

在三掺Ce3+的Ho3+/Yb3+/LiTaO3多晶粉中,发现增强上转换绿光并同时抑制上转换红光的新途径,能有效提高上转换发光的单色性.XRD衍射谱结果表明制备粉体仍为三方晶系.980 nm LD激发下,上转换绿光发光强度随Ce3+掺杂浓度增加而增强,并在Ce3+掺杂摩尔分数达15％时,上转换绿光发光效率达到最大,并同时抑制了上转换红光.Ce3+将2F7/2能级上的能量传递给H03+的516能级来增加上转换绿光.并在高掺Ce3+时,新的交叉弛豫过程使Ce3将2 F7/2能级上的能量传递给H03+的5F4/5S2能级,增强了上转换绿光并同时抑制了上转换红光.     

铒/镱共掺光纤的超荧光研究

研究了铒/镱共掺光纤的超荧光特性,用4.5 m长铒/镱共掺光纤在248 mW的1 064 nm Nd∶YAG激光泵浦下,在峰值波长1 534.96 nm处,光谱3 dB带宽为1.76 nm.其输出光功率达23 mW,斜率效率为12.9%,输出功率稳定性为±0.05 dB.