铒镱共掺磷酸盐玻璃的激光性质

制备了镱铒共掺的磷酸盐玻璃并研究了室温下LD泵浦的连续激光输出性质.在泵浦功率为496 mW时实现了最大输出功率77 mW.讨论了在不同玻璃样品厚度和谐振腔长度时的斜率效率的变化以及在不同玻璃样品厚度,泵浦功率和谐振腔长度时的不同激光模式竞争的动力学行为.结果表明:激光光谱受到光学增益和光学损耗相对大小的限制.     

Effect of Yb3+ concentration on the structures and upconversion luminescence properties of Y2O3:Er3+ ultrafine phosphors

Y2O3:Er3+ ultrafine phosphors with a varying Yb3+ ion concentration were prepared by a urea homogeneous precipitation method.The results of XRD show that all the samples are of a pure cubic structure and the average crystallite sizes can be calculated as 45,34,and 28 nm for Y2O3:Er3+ ultrafine phosphors with Yb3+ ion concentrations of 0,10%,and 20%,respectively.The lattice constant and cell volume of the ultrafine phosphors decrease with enhancing Yb3+ ion concentration.The upconversion luminescence spectra of all the samples were studied under 980 nm laser excitation.The strong green and red upconversion emission were observed,and attributed to the 2H11/2→4I15/2,4S3/2→4I15/2 and 4F9/2→4I15/2 transitions of Er3+,respectively.The intensity of red emission increases with increasing Yb3+ ion concentration.The effect of Yb3+ ion concentration on the structures and upconversion luminescence mechanism were discussed.     

Yb3+/Er3+/Tm3+共掺氧氟碲酸盐玻璃三基色上转换发光研究

制备了一种新的Yb3 /Er3 /Tm3 共掺氧氟碲酸盐玻璃.研究了ZnF2调整Yb3 /Er3 /Tm3 共掺氧氟碲酸盐玻璃的Raman光谱、吸收光谱和上转换荧光光谱.结果发现,该体系玻璃具有较低的声子能量,在980 nm LD激发下,可以同时观察到明显的蓝色(476nm)、绿色(530和545 nm)和红色(656nm)上转换发光.上转换蓝光(476 nm)是由于Tm3 离子1G4→3H6跃迁,上转换的绿光(530和545 nm)是由于Er3 离子2H11/2→4I15/2和4S3/2→4I15/2跃迁,上转换红光(656nm)是由于Er3 离子4F9/2→4I15/2跃迁.根据吸收光谱以及Yb3 、Er3 和Tm3 离子的能级,分析了Yb3 /Er3 /Tm3 共掺氧氟碲酸盐玻璃的上转换发光机理,发现上转换蓝光是一个三光子吸收过程,而上转换绿光和红光均为双光子吸收过程.研究结果表明,Yb3 /Er3 /Tm3 共掺氧氟碲酸盐玻璃是一种三维立体显示用激光玻璃的潜在基质材料.     

Yb3+-and Er3+-doped Y2O3 microcrystals for upconversion photoluminescence and energy transfer with enhancements of near-ultraviolet emission

Yb3+and Er3+were doped into Y2O3 to form Y2O3∶Yb3+,Er3+microcrystals.The effect of doping concentration of Yb3+was studied.The near-ultraviolet(UV)upconversion(...     

Synthesis and upconversion luminescent properties of Er doped and Er-Yb codoped GdOCl powders

Er³⁺ doped and Er³⁺-Yb³⁺ codoped GdOCl phosphors were prepared by modified solid state reaction. X-ray diffraction, scanning electron microscope, and Raman spectrum of the samples were studied. The result of Raman spectrum shows that the cutoff phonon energy of GdOCl is only 505 cm⁻¹, which is beneficial for upconversion luminescence. Infrared-to-visible upconversion emissions were observed under 980 nm diode laser excitation. It was found that the ratio of green to red upconversion emission intensity varies with concentration of the Er³⁺ or Yb³⁺ ion. Laser power and doping concentration dependence of upconversion luminescence were studied to understand the upconversion mechanisms. Excited state absorption and energy-transfer processes are proposed to be the possible mechanisms for the visible emissions.     

Er3+掺杂位置对Er3+:BaTiO3薄膜上转换发光的影响

采用溶胶-凝胶法在LaNiO3/Si衬底上制备Er3+掺杂BaTiO3薄膜.通过XRD、AFM和PL图谱分别研究薄膜的晶体结构、形貌以及上转换发光性能.结果表明,薄膜的微观结构和发光性能与Er3+掺杂晶格的位置有关.A位掺杂薄膜较B位掺杂薄膜具有较小的晶格常数和较好的结晶.PL光谱表明:A位掺杂的薄膜和B位掺杂的薄膜都于528 nm和548nm处获得较强的绿色上转换发光以及在673 nm处获得较弱的红光,分别对应Er3+离子的2H11/2→4I15/2,4S3/2→4I15/2和4F9/2→4I15/2能级跃迁.相对于B位掺杂的薄膜,A位掺杂样品有较强的绿光发射积分强度以及较弱的红光发射相对强度.这种差异可以通过薄膜的结晶状况和交叉弛豫机制来进行解释.     

TSSG法生长Er^3＋／Yb^3＋：KY（WO4）2激光晶体及性能表征

采用TSSG法生长出尺寸为15 mm×18 mm×25 mm的Er3+/Yb3+KY(WO4)2晶体,XRD分析表明所生长的晶体为β-Er/YbKYW.对晶体进行了TG-DTA分析,结果表明晶体的相转变温度和熔点分别为1031℃和1067℃.测得晶体的红外和拉曼光谱,并对峰值与相应的原子基团振动进行了指认.测得样品的吸收光谱,结果表明晶体在380 nm,525 nm,933 nm和981 nm处都存在较强的吸收峰,并计算出主峰981 nm的吸收截面积σabs=3.2×10-20cm2.分别用激发源为488 nm和978 nm对晶体进行了荧光光谱测试,并测得978 nm激发时荧光寿命为4.8 ms.对比分析表明在ErKYW中掺入Yb3+作为敏化离子是可行的,能够提高对泵浦光吸收,有利于得到更强的1540 nm的激光.     

Up-conversion of Nd3+/Yb3+/Tm3+ tri-doped CaTeO3 compound under excitation of 808 nm

Nd3+/Yb3+/Tm3+ tri-doped CaTeO3 compounds were prepared by a solid-state reaction method.Bright blue up-conversion (UC) luminescence at around 476 nm,which corr...     

Thermal, mechanical, and upconversion properties of Er/Yb co-doped titanate glass prepared by levitation method

A novel Er³⁺/Yb³⁺ co-doped titanate glass sphere with diameter of 3.5 mm has been successfully fabricated by levitation method. Its thermal stability, mechanical property and upconversion behavior were investigated. The glass transition temperature T_g, onset crystallization temperature T_c, and peak crystallization temperature T_p, are as high as 820, 895 and 902 °C, respectively. Its Vickers hardness is found to be up to 7.85 GPa. Intense green and red upconversion emissions were obtained in this glassy sample upon 980 nm excitation. The results illustrate good potential of this class of material for practical application in frequency upconversion device. In addition, it is found that heating treatment above T_p can reduce the efficiency of upconversion fluorescence as well as deteriorate the mechanical property, due to the occurrence of La₄Ti₉O₂₄ crystals.     

White luminescence of Ho3+/Tm3+/Yb3+-codoped CaWO4 synthesized via citrate complex route assisted by microwave irradiation

The nanocrystalline Ho³⁺/Tm³⁺/Yb³⁺ co-doped CaWO₄ upconversion (UC) phosphors were successfully synthesized by a modified citrate complex method using microwave irradiation. The citrate complex precursors were heat-treated at temperature ranging from 300 to 700 °C for 3 h. Crystallization of the Ho³⁺/Tm³⁺/Yb³⁺ co-doped CaWO₄ was detected at 400 °C, and entirely completed at 600 °C. The Ho³⁺/Tm³⁺/Yb³⁺ co-doped CaWO₄ heat-treated at 600 °C showed primarily spherical and homogeneous morphology. Under the laser excitation of 980 nm, Ho³⁺/Tm³⁺/Yb³⁺ co-doped CaWO₄ shows the bright white upconversion (UC) emission visible to the naked eye, which is composed of a blue emission at 475 nm from Tm³⁺, and green and red emissions at 543 and 651 nm respectively from Ho³⁺. The coordinates of Ho³⁺/Tm³⁺/Yb³⁺ co-doped CaWO₄ in the Commission International De'eclairage (CIE) chromaticity diagram could be controlled from a cool to a warm white color depending on the Tm³⁺ and Ho³⁺ concentrations. The UC luminescent properties on Tm³⁺ and Ho³⁺ concentrations and related mechanism based on laser pump power were discussed in detail.     

Effect of Yb concentration on the structures and upconversion luminescence properties of Y2O3:Er ultrafine phosphors

Y₂O₃:Er³⁺ ultrafine phosphors with a varying Yb³⁺ ion concentration were prepared by a urea homogeneous precipitation method. The results of XRD show that all the samples are of a pure cubic structure and the average crystallite sizes can be calculated as 45, 34, and 28 nm for Y₂O₃:Er³⁺ ultrafine phosphors with Yb³⁺ ion concentrations of 0, 10%, and 20%, respectively. The lattice constant and cell volume of the ultrafine phosphors decrease with enhancing Yb³⁺ ion concentration. The upconversion luminescence spectra of all the samples were studied under 980 nm laser excitation. The strong green and red upconversion emission were observed, and attributed to the ²H_11/2 → ⁴I_15/2, ⁴S_3/2 → ⁴I_15/2 and ⁴F_9/2 → ⁴I_15/2 transitions of Er³⁺, respectively. The intensity of red emission increases with increasing Yb³⁺ ion concentration. The effect of Yb³⁺ ion concentration on the structures and upconversion luminescence mechanism were discussed.     

Er~(3+)掺杂位置对Er~(3+):BaTiO_3薄膜上转换发光的影响(英文)

采用溶胶-凝胶法在LaNiO3/Si衬底上制备Er3+掺杂BaTiO3薄膜。通过XRD、AFM和PL图谱分别研究薄膜的晶体结构、形貌以及上转换发光性能。结果表明,薄膜的微观结构和发光性能与Er3+掺杂晶格的位置有关。A位掺杂薄膜较B位掺杂薄膜具有较小的晶格常数和较好的结晶。PL光谱表明:A位掺杂的薄膜和B位掺杂的薄膜都于528nm和548nm处获得较强的绿色上转换发光以及在673nm处获得较弱的红光,分别对应Er3+离子的2H11/2→4I15/2,4S3/2→4I15/2和4F9/2→4I15/2能级跃迁。相对于B位掺杂的薄膜,A位掺杂样品有较强的绿光发射积分强度以及较弱的红光发射相对强度。这种差异可以通过薄膜的结晶状况和交叉弛豫机制来进行解释。     

Structure and upconversion luminescence properties of BaYF5:Yb, Er nanoparticles prepared by different methods

BaYF₅:Yb³⁺, Er³⁺ (BYF) upconversion (UC) luminescence nanoparticles have been prepared using co-precipitation and hydrothermal techniques, respectively. Two different fluoride sources were used to synthesize BYF by the hydrothermal method, and the sizes of the as-prepared spherical particles were about 30 nm (NH₄BF₄ as a fluoride source) and 100 nm (NH₄HF₂ as a fluoride source), respectively. While the nanoparticles prepared by the co-precipitation method are irregular, many clusters and agglomerates can be seen. The UC fluorescence has been realized in all the as-prepared BYF samples upon 980 nm excitation. It is found that their luminescence spectra depend strongly upon the preparation method. Factors affecting the upconversion fluorescent intensity have been also studied. The UC emission transitions for ⁴F_9/2-⁴I_15/2 (red), ²H_11/2-⁴I_15/2 (green) and ⁴S_3/2-⁴I_15/2 (green) in the Yb³⁺/Er³⁺ codoped BYF nanoparticles depending on pumping power have also been discussed.     

Spectra and energy levels of Er3+ in Er2O3 powder

The emission and absorption spectra of Er³⁺ ions in Er₂O₃ powder are investigated at room temperature. The crystal field splitting of ⁴I_15/2, ⁴I_13/2, ⁴I_9/2 and ⁴S_3/2 multiplets of Er³⁺ was calculated using a parameterized Hamiltonian including crystal field terms. A final standard deviation of 5.3 cm⁻¹ is obtained between 22 calculated and experimental Stark. The strength crystal field parameters of Er₂O₃ powder are compared to those of erbium doped Y₂O₃ single crystal. In addition, the location of the ground and the first excited states of Er³⁺ in Er₂O₃ powder is determined. The ⁴I_15/2 ground state of Er³⁺ is located at 12750 cm⁻¹ below the valence band edge. The ⁴I_13/2 and ⁴I_11/2 multiplets are set in resonance with the valence band. A configuration coordinate diagram is proposed for Er³⁺ in Er₂O₃ powder.     

A study on microstructure and luminescent properties of oxyfluoride silicate glass-ceramics with (Ho,Yb):NaYF4 crystallites

Glass-ceramics containing NaYF₄ nanocrystals were prepared by heat-treatment from oxyfluoride silicate-based glass doped with Ho³⁺ and Yb³⁺ ions. The formation of crystalline fluoride phase was confirmed by X-ray diffraction and transmission electron microscopy. Absorption and emission spectra revealed that a fraction of Ho³⁺ and Yb³⁺ ions is incorporated into the NaYF₄ ordered lattice influencing spectroscopic features of glass-ceramics in comparison with those of precursor glass. Green up-conversion emission (545 nm) originating in the ⁵S₂ level in glass-ceramics and up-converted red emission (650 nm) originating in the ⁵F₅ level in as-melted glass were observed under optical pumping into Yb³⁺ absorption band and analyzed. Although both emissions in both materials are achieved by two-photon excitations, the relation between green and red emission intensity in glass-ceramics and glass implies that processes relevant to up-conversion phenomena are different. Based on a careful analysis of relaxation dynamics of Ho³⁺ and Yb³⁺ excited states, the mechanisms involved in conversion of the infrared radiation into the visible emission in these materials are proposed and discussed.     

Yb3+对氟磷玻璃结构影响的研究

研究了YbF3对二元系统氟磷玻璃和多元系统氟磷玻璃结构的影响.结果表明,YbF3在氟磷玻璃中不仅作为掺杂体,也作为玻璃基本组成参与网络构筑.随着YbF3含量的增加,YbF3对二元氟磷玻璃结构的影响大于对多元氟磷玻璃结构的影响,同时多元氟磷玻璃具有较好的玻璃结构完整性,Yb3 离子掺杂多元氟磷玻璃有利于获得更好的光谱激光性能.     

Qst32-3超低碳钢显微组织与扭转性能的关系

以经不同工艺退火的Qst32-3超低碳钢为研究对象,利用金相显微镜、硬度计等研究扭转变形过程中显微组织和性能的演化,利用扫描电镜对扭转断口进行形貌观察。结果表明,扭转变形可促进不充分静态再结晶进行。这主要与温度升高促进溶质原子扩散,降低再结晶激活能以及促进位错运动,缩短再结晶形核时间等因素有关。与退火不充分的试样相比,再结晶充分的样品经扭转变形后,其断口宏观呈平齐状。微观断口形貌显示,前者扭转后心部孔洞较大,撕裂棱明显,后者断口心部孔洞小而浅,韧窝呈剪切状,且无明显的撕裂棱存在。表明,充分退火后材料具有更优的扭转性能。     

Gd2O3：Yb，Er纳米材料的制备及上转换发光研究

利用Triton X-100／正己醇／环己烷／正己烷／水制成W／O微乳反胶团体系制备Gd2O3：Yb，Er上转换材料。利用扫描电镜观察氧化物粉体的颗粒形貌均为球形；通过改变掺杂元素Yb和Er的比例，在980nm的红外光激发下，观察研究氧化物颗粒的发光性质。该粉体在波长为980nm的半导体激光器激发下发射出绿色和红色的上转换荧光，分别对应于Er^3＋离子的。^S3／2／^2H11／2→^4I15／2跃迁和。^F9／2→^I15／2跃迁。