Tm3+掺杂光纤激光制冷的理论分析

近年来，掺Tm³⁺：ZBLANP玻璃已成为固体材料激光冷却领域中最有希望的新材料之一，但有关掺Tm³⁺：ZBLANP光纤的激光冷却尚未见到理论研究与实验报道.本文采用一个简单的理论模型，就Tm³⁺：ZBLANP光纤的激光冷却进行了理论研究与分析，讨论了量子效率、抽运功率、背景吸收、出射荧光波长变化和环境黑体辐射等对激光制冷效果的影响，得到了一些有趣的重要结果，可为掺Tm³⁺：ZBLANP光纤的激光冷却实验提供可靠的理论 关键词： 固体激光冷却 反斯托克斯荧光 3+：ZBLANP光纤')" href="#">掺Tm³⁺：ZBLANP光纤     

Yb3+/Ho3+/Tm3+三掺杂LiTaO3多晶材料的上转换发光特性

采用高温固相合成法制备了多组Yb³⁺/Ho³⁺/Tm³⁺不同物质的量分数掺杂的LiTaO₃多晶材料,测试了双掺Yb³⁺/Ho³⁺,Yb³⁺/Tm³⁺和三掺Yb³⁺/Ho³⁺/Tm³⁺的LiTaO₃多晶的X射线衍射图谱、紫外-可见吸收谱和上转换荧光发射谱。X射线衍射(XRD)结果显示,稀土离子掺杂没有改变LiTaO₃多晶的物质结构,这表明稀土离子以取代基质离子的方式进入了晶格中。样品的紫外吸收边显示,增加Ho³⁺或Tm3⁺物质的量分数会导致吸收边先红移再蓝移。在980 nm泵浦光激发下,可见光区域中出现上转换蓝光(475 nm)、绿光(545 nm)和红光(663 nm和650 nm)发射,通过改变LiTaO₃中的激活离子Ho^3+<...     

Tm3+,Yb3+共掺Bi2WO6上转换发光材料的制备及其温度传感性质

用高温固相法制备了不同浓度的Tm³⁺和Yb³⁺共掺杂Bi₂WO₆上转换发光材料.对合成粉末的微结构、上转换发射光谱,以及材料的光学温度传感性质进行了表征和分析.X射线衍射谱结果显示,Tm³⁺和Yb³⁺离子的掺杂基本不影响Bi₂WO₆基质材料的正交晶系结构.在980 nm激发下,Tm³⁺和Yb³⁺掺杂摩尔分数分别是1%和6%时获得样品中Tm³⁺发射强度最大.随激发泵浦功率从199 mW增加到400 mW,1%Tm³⁺,6%Yb³⁺:Bi₂WO₆样品中Tm³⁺的4个发射峰强度均增强.199—400 mW激发功率下,样品光强I和激发功率Pn呈现线性关系.计算该范围激发泵浦功率和Tm³⁺发射强度的关系,得到Tm^3+<...     

Dy3+、Tm3+共掺杂Ca2MgSi2O7的发光特性

采用高温固相法合成了系列Ca₂MgSi₂O₇：Dy³⁺,Tm³⁺发光材料。对样品进行了XRD结构表征,测量了激发光谱、发射光谱、色温和荧光寿命。研究结果表明,Ca₂MgSi₂O₇：Tm³⁺在355 nm激发下显示出蓝色发光,在CIE1931中的色坐标为x=0.165 9,y=0.082 2,色纯度为89%。通过Dy³⁺和Tm³⁺的叠加激发谱带激发,即在349,353,365 nm激发下,Ca₂MgSi₂O₇：Dy³⁺,Tm³⁺显示出青白、冷白和暖白光,相关色温值分别为5 193,9 672,4 685 K。300~500 nm区域间可以有效地激发Ca₂MgSi₂O₇：Dy³⁺,Tm³⁺,并在400~600 nm之间产生蓝光和黄光复合产生的白光,表明该体系可用作白光LED的发光材料。     

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     

Tm3+/Ho3+共掺镓铋酸盐玻璃1.47μm发光特性和能量传递的研究

报道了Tm³⁺/Ho³⁺共掺的镓铋酸盐玻璃14Ga₂O₃-25Bi₂O₃-20GeO₂-31PbO-10PbF₂玻璃1.47μm(S波段)发光和能量传递特征，应用Judd-Ofelt理论计算了玻璃的强度参数Ω_t(t=2，4，6)，自发辐射概率A、荧光分支比β，荧光辐射寿命τ等各项光谱参数以及有效荧光线宽Δλ_eff和峰值发射截面σ^peak_e.通过测量荧光光谱和荧光寿命研究了Ho³⁺离子掺杂浓度对Tm³⁺离子1.47μm波段发光性能的影响，分析了Tm³⁺和Ho³⁺之间的能量传递过程.结果表明一定浓度内Ho³⁺的共掺迅速降低了Tm³⁺：³F₄能级的粒子数，而对³H₄能级粒子数影响不大，从而降低了³F₄和³H₄能级间布居数反转的难度，极大地提高了1.47μm发光效率.研究表明镓铋酸盐玻璃是适用于S波段光纤放大器的一种潜在基质材料，而掺杂一定浓度的Ho³⁺离子有利于提高Tm³⁺离子在1.47μm波段的发光效率. 关键词： 重金属氧化物玻璃 光谱性质 3+/Ho³⁺离子')" href="#">Tm³⁺/Ho³⁺离子 能量传递     

Eu3+,Tm3+共掺GaN薄膜的发光特性和能量传递机制

采用离子注入的方法制备了Eu³⁺,Tm³⁺离子共掺杂GaN薄膜。通过温度依赖光致发光光谱研究了GaN:Eu³⁺薄膜中Eu³⁺的发光特性,发现了三类具有不同温度依赖特性的Eu³⁺发射峰。利用阴极荧光光谱探究了GaN:Eu³⁺,Tm³⁺薄膜的光谱性质,发现随着Tm³⁺剂量的增加,Eu³⁺发射强度以及Tm³⁺的I₄₈₀/I₈₀₆强度比值均发生降低,分析表明存在Eu³⁺→Tm³⁺离子的能量传递,并通过计算分析证明其能量传递机制主要为电偶极子-电偶极子相互作用。通过改变Eu³⁺、Tm³⁺离子在GaN薄膜中的剂量比例,实现了材料发光颜色的有效调控。     

Tm3+掺杂光纤激光制冷的理论分析

近年来,掺Tm3+:ZBLANP玻璃已成为固体材料激光冷却领域中最有希望的新材料之一,但有关掺Tm3+:ZBLANP光纤的激光冷却尚未见到理论研究与实验报道.本文采用一个简单的理论模型,就Tm3+:ZBLANP光纤的激光冷却进行了理论研究与分析,讨论了量子效率、抽运功率、背景吸收、出射荧光波长变化和环境黑体辐射等对激光制冷效果的影响,得到了一些有趣的重要结果,可为掺Tm3+:ZBLANP光纤的激光冷却实验提供可靠的理论依据.     

Yb3+,Tm3+离子掺杂浓度对NaYF4：Yb3+,Tm3+发光光谱的影响

利用高温热溶剂法合成了不同Yb³⁺和Tm³⁺掺杂浓度的NaYF₄：Yb³⁺,Tm³⁺上转换发光纳米粒子。利用扫描电子显微镜、X射线衍射分析、荧光光谱对样品进行形貌和发光性质的表征。结果表明,不同Yb³⁺和Tm³⁺离子掺杂浓度对纳米粒子的上转换发光性质有很大影响。随着Tm³⁺离子浓度的提高,Tm³⁺离子之间的浓度猝灭和交叉弛豫效应对发光强度的影响愈来愈显著,导致纳米粒子的发光猝灭;同样,随着Yb³⁺浓度的提高,纳米粒子的发光强度也是先增大后减小,这是因为Yb³⁺离子浓度掺杂过高导致发光猝灭。     

利用Er3+光学温度传感特性研究Tm3+/Yb3+掺杂NaY(WO4)2微米球的激光辐照热效应

采用微波水热方法合成了Er³⁺/Yb³⁺及Tm³⁺/Yb³⁺两个共掺杂的绣球花状NaY（WO₄）₂微米球样品。XRD结果表明所获得的产物为纯相体心结构的NaY（WO₄）₂,利用SEM观察发现产物粒子结构为纳米片组装成的绣球花状。考虑到红外激光辐照对样品产生加热效应,采用380 nm激发下不同温度的发射光谱获得了Er³⁺/Yb³⁺共掺杂NaY（WO₄）₂微米球的温度传感特性曲线和灵敏度曲线。把Er³⁺/Yb³⁺共掺杂NaY（WO₄）₂与Tm³⁺/Yb³⁺共掺杂的NaY（WO₄）₂按质量比1：10进行混合,采用980 nm激发测量了混合物的上转换发光光谱,研究了激光持续辐照对Tm³⁺/Yb³⁺掺杂NaY（WO₄）₂样品的加热效应和Tm³⁺的¹G₄→³H₆ 跃迁发光强度随激光辐照时间的变化。实验发现980 nm激光辐照使Tm³⁺/Yb³⁺掺杂NaY（WO₄）₂样品的温度持续升高并达到某一平衡温度,Tm³⁺的蓝色上转换发光也随着激光辐照时间的延长而增强,最后达到饱和。此外,在相同条件下,Tm³⁺/Yb³⁺共掺杂样品的激光辐照热效应比Er³⁺/Yb³⁺共掺杂样品的热效应更为显著。     

Dielectric properties and temperature stability of BaTiO3 co-doped La2O3 and Tm2O3

The influence of La₂O₃ and Tm₂O₃ co-doping on the dielectric properties and the temperature stability of BaTiO₃ was investigated. BaTiO₃ ceramics were prepared with the compositional formula of (Ba_1−xLa_x)(Ti_1-x/4−yTm_y)O₃. La₂O₃ and Tm₂O₃ co-doping in BaTiO₃ mainly had effects on an increase in the dielectric constant and the temperature stability, respectively. The increase of La₂O₃ concentration and the decrease of Tm₂O₃ concentration in BaTiO₃ resulted in a decrease of lattice parameter and tetragonality because La³⁺ ion substituting for Ba site is smaller than Ba²⁺ ion and Tm³⁺ ion substituting for Ti site is larger than Ti⁴⁺ ion. With the increase of La₂O₃ and the decrease of Tm₂O₃, the dielectric constant of BaTiO₃ was enhanced in spite of the reduction of tetragonality. P-E hysteresis measurements revealed that this phenomenon was based on the improvement of remanent polarization with the increase of La₂O₃ concentration. The introduction of excess Tm₂O₃ in BaTiO₃ suppressed the grain growth and BaTiO₃ ceramics showed higher temperature stability due to the stable tetragonal structure and the small grain size with the increase of Tm₂O₃ concentration.     

FLUORESCENCE MECHANISMS OF Tm3+- AND Yb3+/Tm3+ DOPED AlF3-BASED FLUORIDE GLASS

A complete set of spectroscopic parameters, including Judd-Ofelt parameters, radiative transition probabilities, radiative lifetime, branching ratios and integrated absorption cross section, have been calculated for Tm³⁺- doped fluoroaluminate (AYF) glass, based on the measured absorption spectra. The mechanism of Tm³⁺→Tm³⁺ and Yb³⁺\Leftrightarrow Tm³⁺ energy transfers and fluorescence properties have been investigated in both Tm³⁺ single-doped and Yb³⁺/Tm³⁺ double-doped AYF glasses. The cross-relaxation process, ³F₄+³H₆→2³H₄, is proved, which makes the optimum Tm³⁺ concentration of 1.77μm fluorescence (³H₄→³H₆) much higher than 1.45μm fluorescence (³F₄→³3H₄) in Tm³⁺:AYF glasses. In Yb³⁺/Tm³⁺:AYF glasses, a stronger concentration quenching is found for the 476nm emission than that for the 797nm emission, and is discussed under the 970nm-excitation.     

Photoluminescence and energy transfer of Tm doped LiIn (WO4)2 blue phosphors

Room temperature steady and time resolved emission spectra of LiIn_1−xTm_x(WO4)2 (where thulium concentration is 0, 0.5, 1, 5 and 10 at%) blue phosphors, under UV excitation energy have been investigated. The concentration quenching effect on the blue emission, due to the (WO₄)⁻² groups and ¹G₄→³H₆ emission transition of Tm³⁺ were studied. Two energy transfer mechanisms are shown. The first takes place between excited (WO₄)⁻² groups and the ¹G₄ energy level of Tm³⁺, and is mainly analyzed by phonon-assisted energy transfer. The second mechanism is due to an energy transfer from the excited Tm³⁺ ions to the surrounding ground state Tm³⁺ ions. The non-exponential decay curves of the ¹G₄ level observed for higher concentrations are analyzed by the Inokuti–Hirayama model. We think that the quenching effect between Tm³⁺ ions is mainly linked to the dipole–dipole interactions.     

Er3+，Tm3+共掺的NaY(WO4)2晶体的光谱分析和上转换发光

在室温下，测量了Er:Tm:NaY(WO₄)₂晶体的吸收光谱、激发光谱、发射光谱以及上转换发光，并运用J-O理论对测量的结果进行了计算，得出了Er:Tm:NaY(WO₄)₂晶体的强度参数.报道了Tm，Er离子间特殊的能量传递和相关上转换，解释了离子间的能级跃迁过程.同时，对于Er增强Tm离子近红外发光的特性也作了充分研究. 关键词： 4)₂晶体')" href="#">Er:Tm:NaY(WO₄)₂晶体 吸收光谱 发射光谱 激发光谱 上转换     

Study on up-conversion emissions of Yb/Tm co-doped GdF3 and NaGdF4

The Yb³⁺/Tm³⁺ co-doped GdF₃ and NaGdF₄ samples were synthesized through a combination method of a co-precipitation and an argon atmosphere annealing procedures. X-ray diffraction analysis indicated that the Yb³⁺/Tm³⁺ co-doped GdF₃ sample crystallized well and was orthorhombic phase, and the Yb³⁺/Tm³⁺ co-doped NaGdF₄ sample was hexagonal phase. With a 980-nm semiconductor continuous wave laser diode as the excitation source, the up-conversion emission spectra of the two samples in the wavelength range of 240-510 nm were recorded. In the up-conversion emissions of the samples, Yb³⁺ transferred energies to Tm³⁺ resulting in their ultraviolet, violet, and blue up-conversion emissions. And, Tm³⁺ simultaneously transferred energies to Gd³⁺, which finally resulted in ultraviolet up-conversion emissions of Gd³⁺. The study on the excitation power dependence of up-conversion fluorescence intensity indicated that there were multi-photon (three-, four-, five-, and six-) processes in the up-conversion emissions of the samples. And the up-conversion emissions of Gd³⁺ and Tm³⁺ in the Yb³⁺/Tm³⁺ co-doped GdF₃ and NaGdF₄ samples were compared studied, too.     

Upconversion emission enhancement of TiO2 coated lanthanide-doped Y2O3 nanoparticles

To investigate the upconversion emission,this paper synthesizes Tm3+ and Yb3+ codoped Y2O3 nanoparticles,and then coats them with TiO2 shells for different coating times.The spectral results of TiO2 coated nanoparticles indicate that upconversion emission intensities have respectively been enhanced 3.2,5.4,and 2.2 times for coating times of 30,60 and 90 min at an excitation power density of 3.21×102 W.cm 2,in comparison with the emission intensity of non-coated nanoparticles.Therefore it can be concluded that the intense upconversion emission of Y2O3:Tm3+,Yb3+ nanoparticles can be achieved by coating the particle surfaces with a shell of specific thickness.     

Role of Al2O3 in upconversion and NIR emission in Tm and Er codoped calcium fluoro phosphorous silicate glass system

In this study, the principal role of Al₂O₃ on the features of the photoluminescence spectra of Tm³⁺ ion and upconversion phenomenon in Tm³⁺ and Er³⁺ codoped CaF₂−Al₂O₃−P₂O₅−SiO₂ glass system has been investigated. The concentration of Al₂O₃ is varied from 2 to 10 mol% while that of Er³⁺ and Tm³⁺ is fixed. IR and Raman spectral studies have indicated that there is a gradual increase in the degree of disorder in the glass network with increase in the concentration of Al₂O₃ up to 6.0 mol%. This is attributed to the presence of Al³⁺ ions in octahedral positions in larger proportions. When the glasses are doped with Tm³⁺ ions, the blue and red emissions were observed, whereas in Er³⁺ doped glasses blue, green and red emissions were observed. When the glasses are codoped with Tm³⁺ and Er³⁺ ions and excited at 790 nm, all the three emission lines were observed to be reinforced, especially in the glasses mixed with 6.0 mol% of Al₂O₃. The IR emission band detected at about 1.8 μm due to ³F₄→³H₆ transition of Tm³⁺ ions is also observed to be strengthened due to codoping. The reasons for enhancement in the intensity of various emission bands due to codoping have been identified and discussed with the help of rate equations for various emission transitions.