Er掺杂氟碲酸盐玻璃的制备和上转换发光性能的研究

结合氟化物玻璃和碲酸盐玻璃的各自优势,在空气气氛下通过熔融法制得了光学性能良好的氟碲酸盐玻璃,该体系玻璃具有较低的声子能量,Er掺杂和Er/Yb共掺氟碲酸盐玻璃在980 nm激光的激发下可实现上转换发光,能观察到明显的绿光和红光。对稀土掺杂玻璃进行吸收光谱的分析,并利用J-O理论计算了振子强度参数和光谱品质因数,有较好的发光能力。通过分析可见光光谱,结合Er的能级结构,得出了实现可见光发光的能量传递过程,并利用速率方程证明该过程是线性衰变和上转换的共同作用。     

蓝绿光上转换荧光输出的稀土掺杂玻璃研究进展

上转换光纤激光器由于在医疗、生命科学等领域应用逐步加强,近年来受到了广泛的重视.本文简要回顾了上转换发光的发展历程,归纳了能够实现蓝绿光输出的稀土离子的种类,详细阐述了近年来具有蓝绿光输出的上转换发光的不同基质玻璃(氟化物玻璃、硫化物玻璃、碲酸盐玻璃、锗酸盐玻璃、铋酸盐玻璃、卤氧化物玻璃)的研究进展,最后,对稀土离子掺杂的玻璃上转换发光的研究动向进行了展望.     

Ho3+/Yb3+掺杂铋镓酸盐光学玻璃的上转换发光

制备了高折射率Ho3 /Yb3 掺杂铋镓酸盐玻璃,用Brewster原理测量玻璃的折射率为2.296.用倒易法计算Yb3 的发射截面面积为2.109×10-20 cm2.在室温,用974nm激光器激发玻璃样品,观察并记录到强烈的双光子上转换荧光.分析认为:铋镓酸盐玻璃中Yb3 直接敏化Ho3 的上转换发光的激发机理是Yb3 到Ho3 的高效能量传递.上转换过程中红光相对强度较强的原因为:玻璃声子能量特性、最大能量声子密度降低和玻璃绿光区强吸收3方面因素增加了5F5能级上的粒子数布居,使5F5→5I8能级的跃迁几率升高,导致红光强度大于绿光强度.     

掺铒钨碲酸盐玻璃光谱性质的研究

研究了掺铒钨碲酸盐玻璃的吸收光谱和荧光光谱。应用JuddOfelt理论计算了Er3+的光谱强度参数Ωt(t=2,4,6)、自发辐射跃迁几率、荧光分支比和辐射寿命。从光谱强度参数的计算说明掺铒钨碲酸盐玻璃中Er—O键的共价性强于碲酸盐玻璃中Er—O键的共价性。玻璃的荧光半高宽为52nm,大于Er3+在磷酸盐和硅酸盐玻璃中的荧光半高宽。应用McCumber理论,计算了钨碲酸盐玻璃中Er3+离子在峰值波长1532nm的受激发射截面,为0.91×10-20cm2,大于Er3+在碲酸盐玻璃中的受激发射截面0.75×10-20cm2。由于掺铒钨碲酸盐玻璃的玻璃转变温度高、有较大的声子能量、较宽的荧光半高宽和较大的受激发射截面,是制作高增益的光波导放大器的理想材料。     

Er3+掺杂氧氟锗硅酸盐玻璃的频率上转换研究

研究了基质玻璃成分对Er^3 掺杂氧氟锗硅酸盐玻璃上转换光谱和Raman光谱的影响,分析了氧氟锗硅酸盐玻璃中Er^3 的上转换发光机理。结果表明：通过975nm的激光二极管激发,在室温下同时观察到强烈的绿光(529,545nm)和红光(657nm)发射,分别是由于Er^3 的。H11/2→^4I15/2,^4S3/2→^4I15/2,和^4F9/2→^4I15/2跃迁,且均为双光子吸收过程。与545nm的绿光发射相比,657nm的红光发光强度比较微弱。随GeO2浓度的增加,基质玻璃的最大声子能量下降,导致无辐射跃迁几率降低,因此绿光和红光的发光强度都增强,但是其对绿光的影响大于红光。     

稀土离子掺杂的多组分玻璃光纤

稀土离子掺杂的多组分玻璃光纤在宽带光纤放大器与上转换光纤激光器中具有重要的应用。本文介绍了稀土离子掺杂多组分玻璃光纤宽带光纤放大器与上转换光纤激光器的工作机理,综述了其最新相关研究进展,并对目前研究中需进一步解决的问题及未来的发展提出了建议与展望。从当前的研究现状来看,碲酸盐玻璃和铋基玻璃应是今后宽带玻璃光纤放大器光纤基质材料的研究重点。对上转换光纤激光器基质材料而言,如何获得更好的具有低声子能量和优良物化性能的玻璃基质,还需进一步探索。     

中红外碲酸盐玻璃及光纤研究进展

近/中红外激光和超连续光源在红外光电对抗、生物医疗、遥测感知和激光探测及测距(LIDAR)等领域具有十分重要的应用价值。近年来,基于软玻璃光纤来产生和传输高亮度近/中红外(特别是2～5μm)激光方面的研究取得了显著进展。在中红外软玻璃基质中,具有相对较低声子能的碲酸盐玻璃对于设计近红外和中红外激光器和放大器、高功率中红外激光传输和传感应用无源光纤具有特别的吸引力。本文重点总结了低损耗碲酸盐玻璃的关键制备技术,并综述了碲酸盐玻璃及光纤在稀土掺杂中红外发光方面的研究进展,最后对碲酸盐玻璃及光纤应用存在的问题和发展趋势进行了总结和展望。     

光学碱度与铋离子掺杂锗酸盐玻璃近红外发光性质之间的关系

制备了铋离子掺杂的碱金属和碱土金属锗酸盐玻璃,并研究了玻璃光学碱度与铋离子近红外发光性质之间的关系。结果表明:铋离子的宽带近红外发光的强度、峰位以及荧光半高宽可以通过锗酸盐玻璃的光学碱度进行调控:随着玻璃光学碱度的增加,红外发光强度下降,半高宽增大,同时发光峰红移;玻璃中Bi~(3+)/Bi~(2+)的摩尔比变化趋势与Duffy光学碱度理论相符。而铋离子近红外发光强度与光学碱度的依存关系表明,近红外宽带发光可能源于低价态铋离子。     

铋碲酸盐玻璃中三价铕离子多通道跃迁发射的三维荧光光谱分析

在初步观察到三价铕离子多通道跃迁发射的基础上,测定了Eu3 掺杂铋碲酸盐玻璃的三维荧光光谱。三维光谱显示,罕见的铕离子5D3、5D2、5D1向下能级跃迁的蓝光和绿光多通道发射在较宽的激发范围内均可被有效地观察和记录到。通过对铕离子能级结构和玻璃基质声子能量的综合分析,认定最大声子能量较低是铋碲酸盐玻璃中获得铕离子多通道跃迁发射主要原因。激发光谱表明,紫色光源可有效激发样品,获得由蓝到红的多峰发射;对于始于5D0态的Eu3 常规发射,氩离子激光器,紫色、蓝色和绿色激光二极管及发光二极管均为有效泵浦光源。     

氟化物玻璃——透过红外线的新材料

<正> 硅酸盐、硼酸盐、磷酸盐、锗酸盐以及它们的混合物所形成的含氧酸玻璃早为人所熟知。这些玻璃都含有MO_4(M=Si, B, P, Ge)四面体的结构单元,强的M-O共价键振动频率很高,从而引起多声子吸收,红外透过截止波长一般在2～3μm处,锗酸盐玻璃能透过     

Preparation of Er3+/Yb3+ co-doped zeolite-derived silica glass and its upconversion luminescence property

A novel upconversion luminescence transparent glass has been successfully synthesized from Er³⁺/Yb³⁺ co-doped zeolite powder by Spark Plasma Sintering (SPS) method through the order–disorder transition process. XRD was used to detect the order–disorder transition process of each phase after SPS. These zeolite-derived silica glasses showed enhanced upconversion luminescence under the excitation of 980 nm diode laser, which was caused by the change of phonon energy according to the results of Raman spectrum, and the corresponding energy transfer mechanism was also discussed in detail.     

An Upconversion Niobium Pentoxide Bulk Glass Codoped with Er3+/Yb3+ Fabricated by Aerodynamic Levitation Method

(82?x)NbO_2.5–17.4LaO_1.5–xZrO₂(NLZ) (x = 7.5, 10, 12.5, 15, 17.5, and 20) bulk glasses codoped with Er³⁺/Yb³⁺ were successfully fabricated by aerodynamic levitation method for the first time. The structure, thermal stability, and luminescent properties of the samples were investigated systemically by XRD, differential scanning calorimetry, and upconversion spectra. Under 980 nm laser excitation, all samples exhibited green and red upconversion emissions centered at 531, 546, and 674 nm. Results showed that the sample with 15 mol% ZrO₂ obtained the most efficient upconversion luminescence and good thermal stability with the glass‐transition temperature as high as 743 °C. The effect of the addition of ZrO₂ on the structure behavior and the phonon density in the glass was investigated by Raman spectra, which are the key factors for the upconversion luminescence intensity.     

掺稀土氟化物玻璃上转换发光材料发展概况

和传统的氧化物玻璃相比,氟化物玻璃具有声子能量低的特点,因此无辐射跃迁几率小,上转换量子效率高,使得掺稀土离子的氟化物玻璃具有高的发光效率.且稀土离子的能级在氟化物玻璃中具有较长的寿命,形成更多的介稳能级,有丰富的激光跃迁.利用稀土离子在氟化物光纤中的上转换特性,可以获得性能优良的光纤激光器.本文简述了掺稀土氟化物玻璃上转换激光材料的发光机理和研究进展.     

Dy~(3+)在ZnO–SiO_2玻璃中的发光特性(英文)

通过溶胶–凝胶法制备xZnO–(100–x)SiO2(x=0,5,10,20,摩尔分数)玻璃,研究ZnO含量对Dy3+发光强度的影响,并且研究Dy3+在紫外光和飞秒激光激发下的发光特性。结果表明:当ZnO摩尔(下同)含量为0、5%和10%,Dy3+的发光强度几乎不变,当ZnO含量达到20%时,Dy3+的发光强度显著增强,归因于基质微结构的明显改变。研究了飞秒激光激发时,Dy3+在ZnO–SiO2玻璃中的上转换发光特性。在飞秒激光(800nm)激发下,观察到强Dy3+的上转换发光。Dy3+的发光强度与泵浦光强度的依赖关系表明:上转换发光过程为双光子机制为主,根据Dy3+的能级,Dy3+在SiO2和ZnO–SiO2玻璃中的上转换发光的机制归因于激发态吸收。     

Temperature and composition dependent excitonic luminescence and exciton-phonon coupling in CdSeS nanocrystals

ABSTRACT: The yellow- and red-emitting CdSeS nanocrystals (NCs) synthesized through one-step organometallic synthesis method are uniformly assembled in polymethyl methacrylate (PMMA). A higher-energy emission band originates from band-edge excitonic state appeared at low temperature. With the Se dopant concentration increasing, the luminescent spectra of CdSeS NCs have a red-shifted emission peak and a shorter luminescent lifetime, which is attributed to the existence of trapping state caused by surface defect and Se dopant. CdSeS NC shows a shorter luminescence lifetime and higher energy emission peak in PMMA matrix than that in toluene, indicating that the former is more favorable to transfer energy through exciton-phonon coupling. The upconversion luminescence (UCL) is observed using 800nm femtosecond laser excitation. The pump power dependence demonstrated UCL spectra of yellow-emitting CdSeS NCs has a slope of 2.2, while that of red-emitting CdSeS NCs has a slope of 1.4. The results demonstrate that the two-photon absorption plays a dominating role when Se concentration of CdSeS NCs is lower, while phonon-assisted UCL by one-photon excitation gradually takes place with the amount of Se dopants increasing.     

Plasmon enhanced upconversion luminescence of NaYF(4):Yb,Er@SiO(2)@Ag core-shell nanocomposites for cell imaging

NaYF(4):Yb,Er@SiO(2)@Ag core-shell nanocomposites were prepared to investigate metal-enhanced upconversion luminescence. Two sizes (15 and 30 nm) of Ag nanoparticles were used. The emission intensity of the upconversion nanocrystals was found to be strongly modulated by the presence of Ag nanoparticles (NPs) on the outer shell layer of the nanocomposites. The extent of modulation depended on the separation distance between Ag NPs and upconversion nanocrystals. The optimum upconversion luminescence enhancement was observed at a separation distance of 10 nm for Ag NPs with two different sizes (15 and 30 nm). A maximum upconversion luminescence enhancement of 14.4-fold was observed when 15 nm Ag nanoparticles were used and 10.8-fold was observed when 30 nm Ag NPs were used. The separation distance dependent emission intensity is ascribed to the competition between energy transfer and enhanced radiative decay rates. The biocompatibility of the nanocomposites was significantly improved by surface modification with DNA. The biological imaging capabilities of these nanocomposites were demonstrated using B16F0 cells.     

Photoluminescence, γ-irradiation and X-ray induced luminescence studies of Sm3+-doped oxyfluorosilicate glasses and glass-ceramics

Sm³⁺-doped oxyfluorosilicate glasses were fabricated through traditional melt quenching technique. After the heat treatment of the prepared glass, transparent SrF₂ nanocrystalline glass-ceramics (GC) were obtained. The amorphous nature of the prepared glasses and crystalline phase (SrF₂) of the GC were confirmed by XRD analysis. Abbe number was calculated for all the prepared glasses by measuring refractive index at different wavelengths. In the framework of Judd-Ofelt (JO) theory, the JO intensity parameters were obtained from the absorption spectra of 1.0 mol% Sm₂O₃-doped glass. The photoluminescence spectrum was recorded with 401 nm excitation. From the analysis of optical spectra and JO parameters, the radiative properties like radiative transition probabilities, branching ratios and radiative lifetimes for the fluorescent levels of Sm³⁺ ions were determined. The effect of γ-irradiation on luminescence properties and X-ray induced luminescence properties were also studied. The emission intensity was increased for GC where as it decreases with increase of γ-irradiation dosages. There are no noticeable changes in the position as well as intensity in photoluminescence and X-ray induced luminescence spectra for GC sample but after the γ-irradiation, the emission intensity was decreased moderately. The luminescence decay profiles for ⁴G_5/2 level were recorded and it is changed from exponential to non-exponential nature for higher Sm³⁺ ion concentrations. The decay profiles which exhibit non-exponential nature are well fitted to the Inokuti-Hirayama model and determined the energy transfer parameters. By using the integrating sphere, the quantum yield values were obtained for all the prepared glasses. The detailed study of the present glasses reveals that these glasses could be useful for radiation shielding and scintillation applications.     

掺Bi的MgO-CaO-Al_2O_3-SiO_2玻璃的吸收和近红外发光特性

研究了4种不同Bi_2O_3掺杂量(0.5%,1%,2%和3%,摩尔分数)的23MgO-11CaO-15Al_2O_3-51SiO_2(摩尔比)玻璃的发光特性。测量了吸收光谱、荧光光谱和荧光寿命。通过电子顺磁共振图谱观察了玻璃受γ辐射前后结构的变化,探讨了玻璃颜色变化和近红外发光的机理。结果表明:在500nm激发下,随着Bi_2O_3掺杂量从1%到3%的逐渐增加,发光波长发生红移,荧光半高宽从312nm增加到352 nm;最优的Bi_2O_3掺杂量为1%,玻璃的受激发射截面和荧光寿命的乘积为3.10×10~(-24)cm~2·s;γ辐射后发光强度的增加和玻璃颜色加深的现象说明Bi掺杂玻璃的近红外发光中心可能是低价态的Bi离子或者Bi团簇。