液相沉淀法制备VO2纳米粉及晶化过程研究

研究了以VOSO4为前驱体，应用液相沉淀法制取VO2纳米粉的制粉技术以及VO2粉末的晶化过程，采用TGA，DSC，XRD，TEM等测试手段对所得粉的物理特性进行了测试分析。试验结果表明：所制取的VO2粉末颗粒粒径介于10nm-30nm之间，该粉体经400％真空热处理10h可完全实现晶化，相变温度为65％。     

Ni~(2 )掺杂透明微晶玻璃的宽带发光和光放大

最近,Ni~(2-)掺杂透明微晶玻璃得到了广泛关注。这种材料结合了晶体材料的高的发光量子效率和玻璃材料的优良的成纤特性,在980 nm激光激发下能在光通讯波段(1200～1700nm)产生超宽带荧光(荧光半高宽>200 nm),同时具有较长的荧光寿命(τ>200μs),有望成为宽带光纤放大器的增益介质。本文介绍了Ni~(2-)掺杂微晶玻璃材料的光学性质、微观结构和发光机理及其最近的研究进展,展望了这类发光材料的应用前景和今后的研究方向。     

Cr~(4+)掺杂Zn_2SiO_4透明微晶玻璃光谱特性

采用高温熔融法和热处理制备了Cr~(4+)掺杂β-Zn_2SiO_4微晶玻璃。通过吸收光谱测试发现,Cr~(4+)在β-Zn_2SiO_4微晶玻璃中处于低的晶体场环境中。推导了Cr~(4+)在β-Zn_2SiO_4微晶玻璃的Racah参数,得到其能级位于~1E和~3T能级交点附近,在808 nm的二极管激发下,在Cr~(4+)掺杂β-Zn_2SiO_4微晶玻璃中可观察到中心波长位于1342nm,半高宽285nm的近红外宽带发射峰,该发射可归于Cr~(4+)在β-Zn_2SiO_4微晶低的晶体场格位的发射。     

TiO_2掺杂对SiO_2-Al_2O_3-MgO系玻璃结构和力学性能的影响

采用传统熔体冷却法制备TiO_2掺杂量为0~1.8wt%的TiO_2/SiO_2-Al_2O_3-MgO系玻璃,探讨了不同TiO_2质量分数对玻璃体积密度、弯曲强度、压缩强度、压缩模量和结构稳定性的影响规律。结果发现:当TiO_2含量小于1.5wt%时,TiO_2/SiO_2-Al_2O_3-MgO系玻璃的光学带隙随着TiO_2含量的增加而减小、玻璃结构更加稳定,其体积密度、弯曲强度、压缩强度以及压缩模量均随着TiO_2含量的增加而上升;当TiO_2含量超过1.5wt%后,该玻璃体系的结构稳定性和力学性能均随着TiO_2含量增加而下降;当TiO_2的质量分数为1.5wt%时,玻璃的光学带隙达到最小值为3.75eV,各项力学性能达到最优,其弯曲强度为110.36 MPa、压缩强度为240.18 MPa、压缩模量为115.03GPa。适量TiO_2的掺杂,减少了玻璃网络结构中非桥氧的数量,使孤立的岛状网络单元重新聚合,从而显著提高了玻璃的结构稳定性和力学性能;但过量的TiO_2迫使TiO_2/SiO_2-Al_2O_3-MgO系玻璃结构中的桥氧键断裂生成非桥氧,由此显著降低了其结构稳定性和力学性能。     

掺Er3+氟铅硅酸盐玻璃的光谱性质和热稳定性研究

制备了掺Er^3 氟铅硅酸盐玻璃，研究了玻璃的物理性质、热稳定性、吸收光谱、荧光光谱和荧光寿命，应用McCumber理论，计算了能级^4I13／2→^4I15／2跃迁的吸收和受激发射截面．结果表明：以PbF2等分子替代PbO含量，样品密度、折射率、热稳定性、吸收截面和受激发射截面降低，但荧光半高宽和荧光寿命增加，对Er^3 离子在不同玻璃基质中带宽特性的比较发现，Er^3 掺杂50SiO2—50PbF2玻璃的带宽特性与碲酸盐和铋酸盐玻璃相当，大于磷酸盐，锗酸盐和硅酸盐玻璃，表明掺Er^3 氟铅硅酸盐玻璃可作为宽带光纤放大器的基质材料。     

Highly Er3+/Yb3+ Co-Doped Fluoroaluminate Glasses for Microchip Laser at 1.54 μm

A series of highly Er3 /Yb3 co-doped fluoroaluminate glasses were investigated in order to develop a microchip laser at 1.54 μm under 980 nm excitation. Measurements of absorption, emission and up-conversion spectra were performed to examine the effect of concentration quenching on spectroscopic properties. In the glasses with Er3 concentrations below 10% (mol fraction), concentration quenching is low and the Er3 /Yb3 co-doped fluoroaluminate glasses gave stronger fluorescence of 1.54 μm from the 4I13/2→ 4I15/2 transition than those of Er3 singly-doped glasses. In the glass with Er3 concentrations above 10%, concentration quenching of 1.54 μm obviously occurs more than that of the Er3 singly-doped samples because of the back energy-transfer from Er3 to Yb3 . To obtain the highest emission efficiency at 1.54 μm, the optimum in mol fraction when the Er3 concentration is less than 10%.     

Upconversion Emission in Er^3＋ Doped Novel Bismuthate Glass

Novel Er3 -doped bismuth lead strontiam glass was fabricated and characterized, and the absorption spectrum and upconversion spectrum of the glass were studied. The Judd-Ofelt intensity parameters Ωt (t=2, 4, 6) were found to be Ω2＝3.27×10-20 cm2, Ω4＝1.15×10-20 cm2, and Ω6＝0.38×10-20 cm2. The oscillator strength, the spontaneous transition probabilities, the fluorescence branching ratios, and excited state lifetimes were also measured and calculated. The upconversion emission intensity varies with the power of infrared excitation intensity. A plot of log Iup vs log IIR yields a straight line with slope 1.86, 1.88 and 1.85, corresponding to 525, 546, and 657 nm emission bands, respectively, which indicates that a two-photon process for the red and green emission.     

超宽带光放大用新型发光材料

介绍了具有ns2np1电子构型的金属离子(原子)掺杂玻璃,过渡金属离子掺杂微晶玻璃和半导体量子点等在近红外光通讯波段具有超宽带发光的新型发光材料.具有ns2np1电子构型的铋掺杂玻璃的σem(发射截面)和σem·.FWHM(full width at half maximum)值分别是掺铒光纤放大器的2～3倍和10倍,σem·τ(荧光寿命)的值是掺钛蓝宝石的3倍.过渡金属离子掺杂微晶玻璃结合了玻璃的易加工性和透明晶体具有高效宽带发光的优点.半导体量子点可利用量子尺寸效应,具有可调节红外宽带发光中心波长等特点.上述材料可能用于宽带光纤放大器的增益介质.探讨了其发光机理并展望了今后的研究方向.     

用于WDM系统的掺稀土玻璃光纤

作为新的光纤放大器增益介质，掺稀土玻璃光纤近年来在WDM传输系统中发展迅速。在介绍了玻璃光纤用作光纤放大器增益媒质优点的基础上，综述了目前掺稀土玻璃光纤研究的要点、种类、性能及其应用实例。     

二氧化钒超细粉末制备技术及进展陕西省自然

对二氧化钒超细粉末的各种制备方法、应用及进展情况进行了综述,并指出了二氧化钒超细粉末制备技术的发展方向.