Measuring the topological charge of optical vortices with a single plate

Measuring the topological charge(TC) of optical vortex beams by the edge-diffraction pattern of a single plate is proposed and demonstrated. The diffraction fringes can keep well discernible in a wide three-dimensional range in this method. The redundant fringes of the diffracted fork-shaped pattern in the near-field can determine the TC value, and the orientation of the fork tells the handedness of the vortex. The plate can be opaque or translucent, and the requirement of the translucent plate ...     

A Novel Ce3＋/Tb3＋ Codoped Phosphate Glass as Down-Shifting Materials for Enhancing Efficiency of Solar Cells

For the purpose of improving conversion efficiency of solar cells by applying the effect of the wavelength conversion of rare earth ions, photo-luminescence and excitation spectrums of Ce3＋-Tb3＋ doped phosphate glass are investigated. Results show that incorporating Ce3＋ ions to Tb3＋-doped phosphate glass can greatly increase the absorption coefficient in the range 300-400 nm and then the energy transfer （ET） from Ce3＋ to Tb3＋ occurs. In addition, increasing Tb3＋ concentration in Ce3＋/Tb3＋ co-doped phosphate glass can greatly enhance the ET efficiency and 545 nm emission intensity. This shows that Ce3＋/Tb3＋ co-doped phosphate glass would be a promising down-shifting material for enhancing the efficiency of solar cells.     

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.     

970 nm抽运下Tm3+/Yb3+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（452nm,476nm）、红光（647nm）及近红外光（791nm）发射,分别对应如下辐射跃迁：^1D2→^3F4、^1G4→^3H6、^1G4→^3F4和^3H4→^3H6;且随着Yb^3＋离子浓度的增加上转换发光增强。在970nm光源抽运下用Yb^3＋敏化Tm^3＋可以显著提高其上转换发光强度,且随着Yb^3＋离子浓度的增加,增强了对抽运光源的吸收并提高了Yb^3＋到T^3＋”的能量转移几率,从而增强了上转换发光强度。     

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

<正>Optically transparent Er~(3+)/Tm~(3+)/Yb~(3+) tri-doped oxyfluoride tellurite based nano-crystallized glass ceramics with the batching composition of 73TeO_2-15ZnO-7ZnF_2-3YF3-1.5YbF3-0.3ErF3-0.2TmF_3(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 microscope 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.     

锗酸盐玻璃中Yb3+/Tm3+/Ho3+掺杂浓度对2 μm发光的影响

为了研究锗酸盐玻璃中采用Yb3+/Tm3+/Ho3+三掺杂方式实现2 μm激光的可行性,研究了3种稀土离子的掺杂浓度对近2 μm发光的影响,从而对稀土离子掺杂浓度进行优化选择以确定理想的掺杂浓度.实验结果表明,在TmF3掺杂摩尔分数为1%时,随着Yb3+浓度的提高Ho3+的2 μm荧光强度增强;当TmF3掺杂摩尔分数为3%时,随着Yb3+浓度的提高Ho3+的2 μm荧光强度降低;随着Yb3+浓度的提高,Tm3+的近2 μm荧光发射会得到增强,且当Tm3+浓度较高时其发光更为明显,这相对削弱了Ho3+的2 μm荧光.Ho3+2 μm发光受Tm3+/Ho3+的浓度比值影响很大,即用980 nm光抽运三掺杂样品,无论Tm3+浓度单一提高还是Ho3+浓度单一降低,对于Ho3+的2μm荧光都是不利的.     

Yb^3+含量对掺Er^3+铝酸盐玻璃光谱性质的影响

采用高温熔融法制备百分比为(100-x)(23.6Al2O3-53CaO-7.7BaO-2.1Na2O-10.3Ga2O3-3.1B2O-0.2Er2O3)-xYb2O3(x=0,0.9,1.9,2.8,3.6,4.5)的铝酸盐玻璃。应用差示扫描量热法、吸收光谱、荧光光谱、红外光谱以及拉曼光谱等检测手段,系统研究了不同Yb^3+离子引入量对玻璃的物性、热稳定性、Er^3+离子光谱性质和结构的影响。结果表明,Yb2O3含量越高,玻璃的密度和折射率越大,抗析晶能力有所增强。随着Yb2O3的增加,玻璃在976 nm吸收系数增大,对应于Er^3+离子的2H11/2→4I15/2、4S3/2→4I15/2以及4F9/2→4I15/2跃迁的527,549,666 nm的上转换发光、红光与绿光发光强度比以及对应于4I13/2→4I15/2的1.53μm近红外荧光强度明显增加。当Yb2O3浓度为3.6%时,铝酸盐玻璃样品在近红外1.53μm荧光最强,此时Yb^3+→Er^3+正向能量传递效率η1最大,约为82.9%。该系列铝酸盐玻璃中Er3+离子1.53μm最大发射截面为0.77×10^-20 cm^2,荧光半高宽最大值为39.4 nm,荧光寿命最大值为4.46 ms。     

Enhancement of up-conversion Yb3＋/Tm3＋/Er3＋ tri-doped tellurite glass luminescence properties in transparent oxyfluoride 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.     

Thermal stability and frequency up-conversion properties of Er~(3+)-doped oxyfluoride tellurite glasses

The thermal properties of 68TeO2-15BaF2-5SrF2-10LaF3-2KF glass were measured by different temperature analysis (DTA). Up-conversion luminescence of Er3 ion in the obtained glass was investigated. Mechanism of up-conversion emission was discussed. The result shows that the obtained oxyfluoride tel-lurite glass 68TeO2-15BaF2-5SrF2-10LaF3-2KF has a good thermal stability (△T = 153.6℃) and strong up-conversion green emissions around 527 nm and 549 nm and red emission at 660 nm. This glass can be a promising host material for up-conversion fiber lasers.     

铈离子价态和OH~-根浓度对Tb~(3+)掺杂磷酸盐玻璃发光性能的影响

通过控制熔制气氛获得了Ce/Tb离子共掺磷酸盐玻璃样品,利用吸收光谱判断Ce离子在玻璃中的价态,并研究了不同Ce离子价态下的激发光谱和发射光谱,进而分析了Ce离子价态对Tb3+离子发光性能的影响。通过除水工艺的控制,获得不同OH-根浓度的Ce/Tb离子共掺磷酸盐玻璃样品,研究了OH-根浓度对Tb3+离子发光性能的影响。结果表明,在Ce/Tb离子共掺磷酸盐玻璃中,采用还原气氛熔制和通气除水工艺,可大大提高Tb3+离子在545 nm处的发光强度。