Effect of aluminum co-doping on the formation of Yb2+ in Ytterbium-doped high silica glass

Yb3+ singly doped and Yb3+/Al3+ co-doped high silica glass samples are prepared,and their luminescent properties are investigated.Al3+ is considered as a beneficial activator for Yb3+-doped glass.However,the experimental result shows that the addition of Al3+ results in the transformation from Yb3+ to Yb2+ and the improvement in the photon luminescence of Yb2+.These characteristics indicate the role of Al3+ in Yb3+-doped glass.     

Effects of charge compensation on red emission in CaYAl3OT7：Eu3＋ phosphor

Monovalent ions Li＋, Na＋, and K＋, as charge compensators, are introduced into CaYA1307： M （M = Eu3＋, Ce~＋） in this letter. Their crystal phases and photoluminescence properties of different alkali metal ions doped in CaYA1307 are investigated. In addition, the influence of charge compensation ion Li＋ which has a more obvious role in improving luminescence intensity on CaYA1307： Eu3＋ phosphor is intentionally discussed in detail and a possible mechanism of charge compensation is given. The enhancement of red emission centered at 618 nm belonging to Eu3＋ is achieved by adding alkali metal ion Li＋ under 393-nm excitation.     

红外飞秒激光诱导Ce3+掺杂闪烁晶体的上转换发光研究

本文研究了红外飞秒激光照射下Ce3 掺杂的YAP和LSO两种闪烁晶体的上转换发光现象。实验发现在飞秒激光泵浦下,这两种晶体的荧光均来自于Ce3 离子的5d-4f跃迁。荧光强度与泵浦光功率之间的依赖关系揭示了Ce3 :YAP和Ce3 :LSO晶体的上转换过程皆由三光子吸收过程所主导。分析表明,Ce3 :YAP和Ce3 :LSO晶体中的三光子吸收是三光子同时吸收。     

离子液体在导电高分子中的应用

综述了离子液体作为介质，在导电高分子合成及其电化学性能测试，以及导电高分子电化学器件中（电化学电容、发光电化学池、驱动器、太阳能电池）的最新研究进展。在此基础上。展望了离子液体在导电高分子中的应用前景。     

272 W quasi-single-mode picosecond pulse laser of ytterbium-doped large-mode-area photonic crystal fiber

A large-mode-area(LMA) ytterbium-doped photonic crystal fiber(PCF) with core NA of 0.034 and core diameter of 50 μm was made by the stack-and-draw technique. The core is formed by Yb~(3+)/Al~(3+)/F-/P~(5+) co-doped silica glass containing 0.09 mol% Yb_2O_3 with an absorption coefficient at 976 nm up to 3.2 d B/m. The core glass with homogeneous distribution of Yb~(3+) ions and refractive index difference of 4 × 10~(-4) compared with pure silica was prepared by the sol-gel method and heat homogenization at 2000°C. Laser power amplification of this LMA PCF was studied using a seed source of 21 ps pulse duration and 48.7 MHz repetition rate at 1030 nm wavelength. With pump power of 520 W, a maximum 272 W(266 k W peak power) quasi-single-mode laser output with M~2 of 2.2 was achieved in a 4.7 m fiber length bent at a diameter of 47 cm with slope efficiency of 52%, and no obvious mode instability, stimulated Raman scattering, or thermal damage on the end facet of the fiber were observed.     

Watt-level Yb-doped silica glass fiber laser with a core made by sol-gel method

A Yb-doped silica glass fiber laser with a core made by sol-gel method is reported. The maximum power of 1.14 W is obtained with a pump power of 5.46 W at a wavelength of 976 nm. The slope efficiency is 34%. The refractive index fluctuation across the core is below 5×10^-4 at a doping level of Yb 0.15 mol%, A203 4.0 mol%, and P2O5 2.0 mol%. High background attenuation of 6 dB/m at 1 053 nm limites the slope efficiency and maximum output power.     

Ultra-broad near-infrared emission of Bi-doped SiO2 Al2O3 GeO2 optical fibers

Bi-doped SiO 2 –Al 2 O 3 –GeO 2 fiber preforms are prepared by modified chemical vapor deposition (MCVD) and solution doping process. The characteristic spectra of the preforms and fibers are experimentally investigated, and a distinct difference in emission between the two is observed. Under 808-nm excitation, an ultra-broad near-infrared (NIR) emission with full-width at half-maximum (FWHM) of 495 nm is observed in the Bi-doped fiber. This observation, to our knowledge, is the first in this field. The NIR emission consists of two bands, which may be ascribed to the Bi 0 and Bi + species, respectively. This Bi-doped fiber is promising for broadband optical amplification and widely tunable laser.     

Bi_2O_3-Li_2O玻璃的热致变色研究

发现氧化和氧化锂所形成的玻璃有着明显的热致变色现象 .温度系数随氧化含量的增加而上升 ,反映了热致变色现象主要来源于氧化 .这种热致变色现象与半导体同样 ,来源于玻璃中的电子 声子相互作用而产生的随温度变化的光学能隙 .氧化重金属氧化物玻璃中高电子密度和低声子能量的化学键是产生强电子 声子相互作用的主要原因     

Energy transfer mechanism in Er3＋ doped fluoride glass sensitized by Tm3＋ or no3＋ for 2.7-μm emission

Enhanced 2.7 μm emission is obtained in Er3＋/Tma＋ and Era＋/Ho3＋ codoped ZBYA glasses. Absorp- tion and emission spectra are tested to characterize the 2.7 μm emission properties of Era＋/Tm3＋ and Era＋/Ho3＋ doped ZBYA glasses and a reasonable energy transfer mechanism of 2.7 μm emission between Er3＋ and Tm3＋Ho3＋） ion is proposed. Codoping of Tm3＋ or Ho3＋ significantly reduces the lifetime of the Era＋： 4I13/2 level due to the energy transfer of Er3＋：4I13/2 →Tm3＋：3F4 or Er3＋：4I13/2 →Ho3＋： 5I7. Thus, the 2.7μm emission is strengthened and the 1,5μm emission is decreased accordingly especially in the Era＋/Tma＋ sample. The upconversion effects between the Er3＋/Tm3＋ and Er3＋/Ho3＋ doped ZBYA glasses are different attribute to the different energy transfer efficiencies. Both of the two codoped samples possess nearly equal large emission cross section （16.6 × 10 -21 cm-2） around 2.7 μm. The results indicate that this Er3＋/Tm3＋ or Er3＋/Ho3＋ doped ZBYA glass has potential applications in 2.7 μm laser.     

Li2O-Nb2O-SiO2系统非晶态离子导体的结构与电学性能

本文采用红外吸收光谱法、X射线散射法和EXAFS方法研究了LiO-Nb₂O-SiO₂系统非晶态离子导体的结构,认为Nb⁵⁺在非晶结构网络中主要是以[NbO₆]形式存在。非晶结构随Nb₂O₅含量的多少而变化。低Nb₂O₅含量时,[NbO₆]相互间以边相连,并与[SiO₄]组成多元环后,形成非晶网络结构。高Nb₂O₅含量时,非晶网络结构主要是以角顶相连的[NbO₆]所组成。根据电导测试结果,讨论了结构与电学性能的关系,认为Li₂O含量在0.45左右,Nb₂O₅,含量在0.3左右组成的非晶材料有最高的电导率。 关键词：