Upconversion luminescence of Tm^3＋/Yb^3＋ codoped oxyfluoride glasses

Novel oxyfluoride glasses are developed with the composition of 30SiO2-15Al2O3-28PbF2-22CdF2-0.1TmF3 - xYbF3 - （4.9 - x） AlF3（x=0, 0.5, 1.0, 1.5, 2.0） in tool fraction, Furthermore, the upconversion luminescence characteristics under a 970nm excitation are investigated. Intense blue, red and near infrared luminescences peaked at 453nm, 476nm, 647nm and 789nm, which correspond to the transitions of Tm^3＋： ^1D2 →^3F4, ^1G4 →^3H6, ^1G4 →^3F4, and ^3H4 →^3H6, respectively, are observed. Due to the sensitization of Yb^3＋ ions, all the upconversion luminescence intensities are enhanced considerably with Yb^3＋ concentration increasing. The upconversion mechanisms are discussed based on the energy matching rule and quadratic dependence on excitation power. The results indicate that the dominant mechanism is the excited state absorption for those upconversion emissions.

Tm(0.1)Yb(10.9)氟氧化物玻璃陶瓷的直接上转换敏化发光

本文首次研究了掺杂Ｔｍ （０．１）Ｙｂ（１０．９）氟氧化物玻璃陶瓷在９６６ ｎｍ 半导体激光激发下的直接上转换敏化发光现象。测量发现存在很强的１Ｇ４ →３Ｈ６ 的４７７ ｎｍ 三光子和３Ｆ４ →３Ｈ６ 的７９９．５ ｎｍ 双光子上转换荧光以及较弱的１Ｄ２ →３Ｈ６ 的３６１ ｎｍ ，１Ｄ２→３Ｈ４ 的４４９．５ ｎｍ ，１Ｇ４→３Ｆ４ 的６４７．０ ｎｍ 和３Ｆ３→３Ｈ６ 的（６７９．５ ｎｍ ，６９８．５ ｎｍ ）的多个上转换发光。

Tm(0.1)Yb(10.9)氟氧化物玻璃的直接上转换敏化发光

本文首次研究了Tm(0 1)Yb(10 9)氟氧化物玻璃在 96 6nm半导体激光激发下的直接上转换敏化发光现象。测量发现存在很强的 1G4 → 3 H6的 474nm三光子和较弱的1D2 →3 H6的 36 2nm ,1D2 →3 F4 的 45 2nm ,1G4 → 3 F4 的 6 5 0nm三光子以及3 F3 → 3 H6的 6 81nm二光子上转换发光。

Tm^3＋-Yb^3＋共掺氧氟硅酸盐玻璃热学性能和上转换发光特性研究

稀土掺杂氧氟玻璃是一种优良的上转换发光材料，制备了组分为35SiO2—15AlO1.5-（45-x）PbF2-xCdF2—0．1TmF3—1．5YbF3（x=0，10，20，30）的氧氟硅酸盐玻璃，系统研究了CdF2含量对其热学性能和光学性能的影响。研究表明用CdF2部分替代PbF，可以提高玻璃的热稳定性、使紫外吸收截至边向短波方向移动；随着CdF2含量的增加，开始Tm^3＋蓝光和红光上转换发光增强缓慢，而后迅速增强．而近红外上转换发射先显著增强后增强放缓；由于蓝光和近红外发光强度远大于红光发光强度，所以该氧氟玻璃更适合于蓝光和近红外发光材料。最后，探讨了Tm^3＋的上转换发光机理。

Tm^3＋／Yb^3＋共掺碲镓酸盐玻璃上转换光谱研究

研究了808nm和977nm激光二极管泵浦下铥／镱共掺TeO3～Ga2O3-BaO-ZnO玻璃光谱特性并讨论了Tm^3＋离子浓度对上转换光谱的影响。在977nm激光二极管泵浦下，观测到Tm^3＋／Yb^3＋共掺碲镓酸盐玻璃强476nm上转换蓝色（^1G4→^3H6）和较弱的650nm上转换红色（^1G4→^3F4和^3F2．3→^3H6）荧光。分析表明476nm蓝光辐射为三光子吸收过程．650nm红光为双光子和三光子混合吸收过程；在808nm激光二极管泵浦下，上转换蓝色荧光为双光子吸收过程。实验发现．随Tm^3＋离子掺杂浓度的增加，Tm^3＋离子的上转换荧光强度也随之增加，当Tm2O3掺杂浓度超过0．2mol％时，荧光强度开始下降，出现明显荧光猝灭现象；当Tm^3＋为0．3mol％时，蓝光对红光的强度比为8倍。

Tm^(3+)-Yb^(3+)共掺杂的碲酸盐玻璃和光纤的光谱特性

研究了Tm3+-Yb3+共掺杂的碲酸盐玻璃和光纤在980nm激光二极管激发下的可见与近红外光谱性质。室温下,Tm3+-Yb3+共掺杂的碲酸盐玻璃在480,800nm处观测到了很强的上转换发光,在650nm观测到一较弱的上转换发光,它们分别来自Tm3+离子的1G4→3H6,3H4→3H6和1G4→3F4跃迁;在1020,1810nm处观测到近红外发射,它们分别属于Yb3+离子的2F5/2→2F7/2跃迁和Tm3+离子的3F4→3H6跃迁。研究了其发光特性与Tm3+及Yb3+的浓度的依赖关系。此外,在980nm激光激发下,还观测到Tm3+-Yb3+共掺杂的碲酸盐玻璃光纤在1060,1470,1910nm附近的近红外发射。详细讨论了其发光机制,该材料可望用于制作蓝色上转换光纤激光器、S-波段光纤放大器以及在医疗诊断和遥感中有着广泛的应用的1.9μm光纤激光器。

Research on upconversion luminescence in new Er^(3+)/Yb^(3+) codoped oxyfluoride borosilicate glass ceramics

The upconversion luminescence of Er^3＋/Yb^3＋ ions is researched in a novel transparent oxyfluoride borosil- icate glass and glass ceramics under 980-nm excitation. Fluoride nanocrystals Ba2YF7 are successfully precipitated in glass matrix, which is affirmed by the X-ray diffraction results. Compared with the parent glasses, significant enhancement of upconversion luminescence is observed in the Er^3＋/Yb^3＋ codoped transparent glass-ceramics, which may be due to the variation of coordination environment around Er^3＋ and Yb^3＋ ions after crystallization. The possible upconversion mechanism is also discussed.

Intense upconversion luminescence of Er^(3+)/Yb^(3+) codoped oxyfluoride borosilicate glass ceramics containing Ba_2GdF_7 nanocrystals

Er3+/Yb3+-codoped transparent oxyfluoride borosilicate glass ceramics containing Ba2GdF7 nanocrystals were prepared and spectroscopic properties of rare earth ions were investigated. Fluoride nanocrystals Ba2GdF7 were successfully precipitated in glass matrix, which was confirmed by X-ray diffraction (XRD) and transmission electron microscopy (TEM) results. In comparison with the as-made precursor, significant enhancement of upconversion luminescence was observed in the Er3+/Yb3+ codoped oxyfluoride glass ceramics, which may be due to the variation of coordination environment around Er3+ and Yb3+ ions after crystallization. The transition mechanisms of the green and red upconversion luminescence were ascribed to a two-photon process, and that of the blue upconversion luminescence was a three-photon process.

Enhancement of up-conversion luminescence properties in Yb^(3+)/Tm^(3+)/Er^(3+) tri-doped transparent oxyfluoride tellurite glass ceramics

Optically transparent Er3＋/Tm3＋/Yb3＋ tri-doped oxyfluoride tellurite based nano-crystallized glass ceramics with the batching composition of 73TeO2-15ZnO-7ZnF2-3YF3-1.5YbF3-0.3ErF3-0.2TmF3 （mol%） is prepared by a conventional melting quenching and the subsequent heat treatment processes. The sizes of grown nano-crystals in glass matrix appear to be smaller than 100 nm from the scanning electron mi- croscope measurement. Visible up-conversion luminescence of the as melted glass and glass ceramics is investigated. The three-color up-conversion luminescence intensities by 980-nm pumping are increased significantly due to the heat treatment, and the blue intensity increases with a higher magnitude than other wavelengths after heat treatment.

Spectroscopic investigations on Er^(3+)/Yb^(3+)-doped oxyfluoride glass ceramics containing YOF nanocrystals

Spectroscopic properties of Er3＋/Yb3＋-doped transparent oxyfluoride borosilicate glass ceramics containing YOF nanocrystals were systematically investigated. X-ray diffraction （XRD） confirmed the formation of YOF nanocrystals in the glassy matrix. Based on the Judd-Ofelt theory, the intensity parameters Ωi （i=2, 4, 6）, spontaneous emission probability, radiative lifetime, radiative quantum efficiency and the effective emission bandwidth were investigated. The upconversion luminescence intensity of Er3＋ ions in the glass ceramics increased significantly with the increasing crystallization temperature. The transition mechanisms of the green and red upconversion luminescence were ascribed to a two-photon process, and the blue upconversion luminescence was a three-photon absorption process.

Tm^(3+)Yb^(3+)共掺铋碲酸盐玻璃中的高效蓝色上转换荧光

制备了高折射率Tm3+Yb3+共掺杂铋碲酸盐玻璃,利用棱镜耦合法测量出玻璃在632.8和1550nm波长处的折射率分别为2.0365和1.9795.对玻璃的吸收、荧光和红外透过光谱展开了测试与分析,根据JuddOfelt理论对吸收光谱进行拟合,求得Tm3+的振子强度参数Ωt(t=2,4,6)分别为3.90×10-20,2.03×10-20和9.03×10-21cm2,并进一步计算了Tm3+在玻璃中各能级跃迁的振子强度、自发辐射跃迁概率、辐射寿命和荧光分支比等光谱参数.在980nm激光激发下测得强的蓝色三光子上转换和近红外双光子上转换荧光.宽的红外透过窗口、高的折射率和强的蓝色上转换荧光表明,Tm3+Yb3+共掺铋碲酸盐玻璃有希望成为高效的上转换发光和激光材料.

Yb^(3+)敏化Tm^(3+)掺杂氧卤碲酸盐玻璃的上转换发光研究

研究了Yb2O3浓度对Tm3+/Yb3+共掺氧卤碲酸盐玻璃的上转换发光的影响,分析了上转换发光机理。结果发现,通过980 nm的激光二极管激发,在室温下同时观察到强烈的蓝光(475 nm)和微弱的红光(649 nm),分别是由于Tm3+离子1G4→3H6和1G4→3F4跃迁产生的;上转换机理分析表明,上转换蓝光和红光都是由于双光子吸收过程。随Yb2O3浓度增加,Yb3+离子寿命降低,Yb3+到Tm3+的能量转移效率增加,上转换蓝光和红光强度先增加,在Yb2O3摩尔比为3时达到最大,然后降低。分析认为,Yb3+的浓度猝灭主要是由于3H4(Tm3+)→2F5/2(Yb3+)反向能量转移的结果。结果表明Yb3+敏化Tm3+掺杂氧卤碲酸盐玻璃是一种上转换蓝光激光器的潜在基质材料。

Tm^3＋/Yb^3＋共掺氟氧硅铝酸盐玻璃陶瓷蓝色上转换发光研究

按摩尔百分比制备了组分为30SiO2-(20-x-y)Al2O3-40PbF2-10CdF2-xTm2O3-yYb2O3的两组Tm3+/Yb3+共掺杂氟氧硅铝酸盐上转换蓝色发光玻璃陶瓷材料,测量了其在980 nm激光激发下的上转换发光光谱,分析了此材料中Tm3+/Yb3+发光体系的上转换发光机理,并系统地研究了Tm3+离子和Yb3+离子的浓度对该材料上转换发光性能的影响.研究表明:由于Tm3+离子之间存在着交叉弛豫作用使得蓝光(477 nm)发光强度随Tm3+离子浓度增加而减弱,实验获得的最佳掺杂浓度为x=0.025(mol%);另外,在Tm3+/Yb3+上转换发光体系中,Yb3+离子合作上转换能量传递过程和三光子过程是共同存在的,随着Yb3+离子浓度的增加,Tm3+离子3H4能级到Yb3+离子2F5/2能级的反向能量传递增强使3H4能级上粒子布居数不断减少,三光子过程作用减弱;但是Yb3+离子合作上转换能量传递过程则发挥越来越大的作用,使上转换蓝光强度总体上不断增加.

Bi_2O_3对Tm^(3+)/Ho^(3+)/Yb^(3+)共掺碲酸盐玻璃三基色上转换发光的影响

用高温熔融法制备了Tm3+/Ho3+/Yb3+共掺碲酸盐玻璃样品,在TeO2-ZnO-La2O3玻璃组分的基础上,引入声子能量较低的重金属氧化物Bi2O3,研究了Bi2O3组分对基质样品拉曼光谱和Tm3+/Ho3+/Yb3+共掺样品上转换发光光谱的影响。结果发现,在975 nm波长激光二极管(LD)激励下,制备的碲酸盐玻璃样品中可以观察到强烈的红光(662 nm)、绿光(546 nm)和蓝光(480 nm)三基色上转换发光。随着重金属氧化物Bi2O3组分含量的增加,玻璃基质的最大声子能量降低,Tm3+/Ho3+/Yb3+共掺样品的三基色上转换发光强度均有所提高,且Bi2O3组分的引入对上转换蓝光发光强度的影响要大于其对绿光和红光的影响。

Tm^(3+)-Er^(3+)-Yb^(3+)共掺的氟氧化物玻璃陶瓷的发光特性

制备了Tm3+-Er3+-Yb3+共掺含NaYF4纳米晶的透明氟氧化物玻璃陶瓷。根据X射线粉末衍射结果确认玻璃中包含NaYF4纳米晶。测量了样品的吸收光谱和在980 nm LD红外光激发下的荧光光谱。同时观察到了明亮蓝光(475 nm)、绿光(530,550 nm)和红光(651,668 nm)。上转换蓝光是由于Tm3+离子1G4→3H6跃迁,上转换绿光是由于Er3+离子的2H11/2→4I15/2和4S3/2→4I15/2跃迁,上转换红光分别是由于Tm3+离子1G4→3H4和Er3+离子4I9/2→4I15/2跃迁。在Tm3+和Yb3+浓度比一定的情况下,通过改变Er3+的浓度来研究红、绿、蓝光的光强积分与Tm3+-Er3+-Yb3+浓度比的变化关系。为了得到上转换荧光的发光机制,基于稀土离子的能级图,研究了上转换发光强度与激发功率的对数关系。

激光二极管抽运下铥/镱共掺碲镓酸盐玻璃光谱特性研究

研究了808nm和977nm激光二极管抽运下铥/镱共掺TeO2-Ga2O3-R2O(R=Li,Na,K)玻璃光谱特性.利用Judd-Ofelt理论计算了Tm3+离子在碲镓酸盐玻璃中自发辐射跃迁概率、荧光分支比和辐射寿命等光谱参数.在977nm激光二极管抽运下,观测到Tm3+/Yb3+共掺碲镓酸盐玻璃很强的476nm上转换蓝光(1G4→3H6)和较弱的650nm上转换红光(1G4→3H4和3F2,3→3H6).分析表明476nm蓝光发射为三光子吸收过程,650nm红光发射为双光子和三光子混合吸收过程;而在808nm激光二极管抽运下,玻璃上转换蓝色荧光为双光子吸收过程.实验发现,随着碱金属离子半径的增大,977nm激光二极管抽运下蓝光上转换发光强度增强,而用808nm激光二极管抽运蓝光上转换发光无明显的变化.