Bi-doped BaF2 crystal for broadband near-infrared light source

Bi-doped BaF2 crystal was grown by the temperature gradient technique and its spectral properties were investigated. The absorption, emission and excitation spectra were measured at room temperature. Two broadband emissions centered at 1070 and 1500 nm were observed in Bi-doped BaF2 crystal. This extraordinary luminescence should be ascribed to Bi-related centers at distinct sites. We suggest Bi2+ or Bi+ centers adjacent to F vacancy defects are the origins of the observed NIR emissions. (C) 2009 Optical Society of America

Photoluminescence of Ag nanoparticle embedded Tb3+/Ce3+ codoped NaYF4/PVP nanofibers prepared by electrospinning

Ag nanoparticle embedded NaYF4:0.05Tb center dot chi Ce/ PVP (PVP stands for poly(vinyl pyrrolidone)) composite nanofibers have been prepared by electrospinning. A field emission scanning electron microscope and x-ray diffraction have been utilized to characterize the size, morphology and structure of the as-prepared electrospun nanofibers. Obvious photoluminescence (PL) of NaYF4:0.05Tb center dot 0.05Ce/PVP electrospun nanofibers due to the efficient energy transfer from Ce3+ to Tb3+ ions is observed. The PL intensity of the electrospun nanofibers decreases gradually with the addition of Ag nanoparticles. No obvious surface plasmon resonance enhanced luminescence is observed. The reasons for the weakening of the emission intensity with the addition of Ag nanoparticles have also been discussed in this work.

Effect of cerium oxide on the precipitation of silver nanoparticles in femtosecond laser irradiated silicate glass

We investigated the effect of cerium oxide on the precipitation of Ag nanoparticles in silicate glass via a femtosecond laser irradiation and successive annealing. Absorption spectra show that Ce3+ ions may absorb part of the laser energy via multiphoton absorption and release free electrons, resulting in an increase of the concentration of Ag atoms and a decrease of the concentration of hole-trapped color centers, which influence precipitation of the Ag nanoparticles. In addition, we found that the formed Ag-0 may reduce Ce4+ ions to Ce3+ ions during the annealing process, which inhibits the growth of the Ag nanoparticles.

Optical properties of transparent alkali gallium silicate glass-ceramics containing Ni2+-doped beta-Ga2O3 nanocrystals

Broadband near-infrared (IR) luminescence in transparent alkali gallium silicate glass-ceramics containing N2+-doped beta-Ga2O3 nanocrystals was observed. This broadband emission could be attributed to the T-3(2g) (F-3) -> (3)A(2g) (F-3) transition of octahedral Ni2+ ions in glass-ceramics. The full width at half-maximum (FWHM) of the near-IR luminescence and fluorescent lifetime of the glass-ceramic doped with 0.10 mol% NiO were 260 nm and similar to 1220 mu s, respectively. It is expected that transparent Ni2+-doped beta-Ga2O3 glass-ceramics with this broad near-IR emission and long fluorescent lifetime have potential applications as super-broadband optical amplification media.

Fluorescent Ag nanoclusters in glass induced by an infrared femtosecond laser

We report a method for the selective introduction of fluorescent Ag nanoclusters in glass. Extinction and photoluminescence spectra show that a fraction of the Ag atoms are generated through femtosecond laser induced multiphoton reduction and then aggregate to form Ag nanoclusters after heat treatment. Red luminescence from the irradiated region is observed under blue or green laser excitation. The fluorescence can be attributed to interband transitions within Ag nanoclusters. This method provides a novel route to fabricate fluorescent nanomaterials in 3D transparent materials. (c) 2007 Elsevier B.V. All rights reserved.

Optical spectroscopy and energy transfer of Er3+/Ce3+ in B2O3-doped bismuth-silicate glasses

Ce3+ and B2O3 are introduced into erbium-doped Bi2O3-SiO2 glass to enhance the luminescence emission and optic spectra characters of Er3+. The energy transfer from Er3+ to Ce3+ will obviously be improved with the phonon energy increasing by the addition of B2O3. Here, the nonradiative rate, the lifetime of the I-4(11/2) -> I-4(3/2) transition, and the emission intensity and bandwidth of the 1.5 mu m luminescence with the I-4(13/2) -> I-4(5/2) transition of Er3+ are discussed in detail. The results show that the optical parameters of Er3+ in this bismuth-borate-silicate glass are nearly as good as that in tellurite glass, and the physical properties are similar to those in silicate glass. With the Judd-Ofelt and nonradiative theory analyses, the multiphonon decay and phonon-assisted energy-transfer (PAT) rates are calculated for the Er3+/Ce3+ codoped glasses. For the PAT process, an optimum value of the glass phonon energy is obtained after B2O3 is introduced into the Er3+/Ce3+ codoped bismuth-silicate glasses, and it much improves the energy-transfer rate between Er3+ I-4(11/2)-I-4(13/2) and Ce3+ F-2(5/2) -> F-2(7/2), although there is an energy mismatch. (c) 2007 Optical Society of America.

Strong visible up-conversion emission in Tb3+, Tm3+ and Tb3+-Tm3+ co-doped tellurite glasses sensitized by Yb3+

Up-conversion luminescence characteristics under 975 nm excitation have been investigated with Tb3+/Tm3+/Yb3+ triply doped tellurite glasses. Here, green (547 nm: D-5(4) --> F-7(4)) and red (660 nm: D-5(4) --> F-7(2)) up-conversion (UC) luminescence originating from Tb3+ is observed strongly, because of the quadratic dependences of emission intensities on the excitation power. Especially, the UC luminescence was intensified violently with the energy transfer from the Tm3+ ions involves in the Tb3+ excitation. To the Tb3+/Tm3+/Yb3+ triply doped glass system, a novel up-conversion mechanism is proposed as follows: the energy of (3)G(4) level (Tm3+) was transferred to D-5(4) (Tb3+) and the 477-nm UC luminescence of Tm3+ was nearly quenched. (C) 2006 Elsevier B.V. All rights reserved.

Cr^4＋：YAG被动调QNd：YAG陶瓷激光器的研究

介绍了近几年迅速发展的一种新型激光介质——透明Nd：YAG多晶陶瓷的发展状况，对比分析了多晶陶瓷与单晶的光谱特性、激光特性和连续实验研究情况。并对钛宝石激光器调谐至808nm，端面抽运Nd：YAG陶瓷被动调Q全固态激光器的脉冲运转进行了较为详细的理论分析和实验研究。采用初始透射率为90％的Cr^4＋：YAG可饱和吸收晶体，被动调Q的阈值功率为119mW，当端面抽运功率为465mW时，获得波长为1064nm，脉宽为16ns，重复频率为18．18kHz，单脉冲能量为3．4μJ，平均输出功率为61mW的稳定调Q

970nm抽运下Tm^3／Yb^3＋共掺氧氟玻璃的频率上转换发光

稀土离子掺杂的氧氟玻璃是一种新型上转换发光材料。制备了Tm^3／Yb^3＋单掺、共掺的摩尔分数为n（SiO2）-0．30，n（PbF2）-0．50，n=（Al2O3）=0．15，n（AlF3）=（0．049-x），n（TmF3）=y，n（YbF3）=x（x=0，0．001，0．010，0．015，0．020，y=0，0．001）系统氧氟玻璃，研究了其上转换发光特性、分析了其上转换发光机理。研究发现，在970nm抽运光源激发下，Tm^3＋单掺时没有可见光上转换发射；而加入Yb^3＋后产生了强的蓝光（452n

氟磷酸盐玻璃的应用研究进展

氟磷酸盐玻璃系统南于其特殊的光学性能和优良的机做与热学性能一直是特种光学玻璃材料领域的一个研究热点。总结了氟磷酸盐玻璃的分类及玻璃组分与其结构的关系，综述了氟磷玻璃在光学器件、高能高功率激光玻璃、光纤激光器、光纤放大器及上转换发光基质材料等领域上的应用，并对其未来的发展进行了展望。

卤化铅调整Tm^3＋／Yb^3＋共掺碲酸盐玻璃上转换发光研究

研究了卤化铅调整Tm^3+／Yb^3+共掺碲酸盐玻璃的热稳定性能、Raman光谱和上转换发光光谱，分析了Tm^3+／Yb^3+共掺氧卤碲酸盐玻璃的上转换发光机理．结果发现：混合卤化铅调整Tm^3+／Yb^3+共掺碲酸盐玻璃具有好的热稳定性能、低的声子能量、强的上转换蓝光．这表明混合卤化铅调整Tm^3+／Yb^3+共掺碲酸盐玻璃是一种上转换蓝光激光器的潜在基质材料．

三维立体显示用稀土掺杂氧卤碲酸盐玻璃

制备了一种新的Er^3+／Tm^3+/Yb^3+共掺氧卤碲酸盐玻璃。研究了基质玻璃的热稳定性能、Raman光谱和上转换发光。发现：氧卤碲酸盐玻璃具有好的热稳定性能和低的声子能量，在980nmLD激发下，可同时观察到明显的蓝色(476nm)、绿色(530nm和545nm)和红色(656nm)上转换发光。上转换蓝光(476nm)是由于Tm^3+离子1^G4→3^3H6跃迁，上转换的绿光(530nm和545nm)是由于Er^3+离子2^H11/2→4^I15／2和4^S3/2→4^I15/2跃迁，上转换红光(6

频率上转换掺稀土氧氟纳米微晶玻璃的研究进展

本文综述了近年来用于上转换发光的掺稀土离子氧氟微晶玻璃的研究概况，系统阐述了氧氟微晶玻璃中的上转换发光特性及其机理，提出了值得进一步研究的工作并对掺稀土离子氧氟微晶玻璃未来的前景做出了展望。

CE3+对ER3+/Yb3+共掺TeO2-WO3-ZnO玻璃发光性能的影响

Ce3+ ions were introduced into the Er3+/Yb3+ -codoped TeO2-WO3-ZnO glasses, and the effect of Ce3+ on the emission properties at 1.5 mu m band and the upconversion luminescence of Er3+ in the glasses was investigated. With the increasing of Ce3+ concentration, the emission intensity of Er3+ at 1.5 mu m band increases firstly, and then decreases. The optimal doping concentration of Ce3+ is about 2.07 x 10(20)/cm(3). As for the Er3+ emission at 1.5-mu m band, the fluorescence lifetime decreases a little from 3.4ms to 3.0ms, while the full width at half maximum (FWHM) hardly changes with the increase of Cc 3+ concentration. Due to the effective cross relaxation between Ce3+ and Er3+ : Er3+ (I-4(11/2)) + Ce3+ (F-2(5/2)) -> Er3+ (I-4(13/2)) + Ce3+ (F-2(7/2)), the upconversion emission intensity of Er3+ is reduced greatly. But when Ce3+ -doping concentration is too high, the other cross relaxation between Ce3+ and Er3+ : Er3+ (4I(13/2)) + Ce3+ (F-2(5/2)) -> Er3+ (I-4(15/2)) + Ce3+ (F-2(7/2)) happens, which depopulates the I-4(13/2) level of Er3+ and results in the decrease of the emission intensity and fluorescence lifetime of Er3+ at 1.5 mu m band.

掺铒氟（卤）磷碲酸盐玻璃的上转换发光性能研究

研究了掺铒氟（卤）磷碲酸盐玻璃的吸收光谱和上转换荧光光谱，探讨了Er^2＋在氟（卤）磷碲酸盐玻璃中的上转换发光机理．在975nm激光二极管抽运下产生强烈的上转换红光及绿光。且红光的发光强度要远远大于绿光．以PbCl2取代PbF2后，红光的发光强度下降，而绿光却没有明显变化；以ZnCl2取代ZnF2达5mol％时，红光和绿光的发光强度均明显增大．