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.     

荧光俘获效应对掺铒氧化物玻璃光谱性质的影响

测试了不同掺杂浓度和样品厚度下掺铒磷酸盐和碲酸盐玻璃的吸收光谱、荧光光谱和荧光寿命,计算了Er3+离子在1.53 μm处的吸收截面(σa)、发射截面(σe)、自发辐射跃迁概率(Arad)、辐射跃迁寿命(τrad)、以及辐射跃迁量子效率(η)等光谱参数.讨论了荧光俘获效应对掺铒磷酸盐和碲酸盐玻璃光谱性质及光谱参数的影响.结果表明即使在铒离子低掺杂浓度(0.1 mol% Er2O3)下,荧光俘获效应也普遍存在于掺铒玻璃材料中,使得荧光寿命(τf)和荧光半高宽(FWHM)随样品的厚度和铒离子掺杂浓度增加而增大,导致碲酸盐和磷酸盐玻璃中τf分别增加11%-37%和6%-17%,FWHM分别增加15%-64%和11%-55%,使得掺铒玻璃材料的放大品性参数(σe×FWHM) 也相应被估高.由于铒离子在碲酸盐玻璃中在1.53 μm处吸收和发射截面重叠面积较大,加之铒离子在前者基质中的发射截面高于后者,使得掺铒碲酸盐玻璃中的荧光俘获效应高于磷酸盐玻璃.     

Blue upconversion luminescence in Tm~(3+)/Yb~(3+) co-doped new oxyfluoride tellurite glass

Solid-state blue and green light sources are desirablefor high-density optical storage, color displays, optoelec-tronics, and medical diagnostics[1-4]. Tm3+ is the moststudied in rare-earth ions for blue laser operation basedupon upconversion[5,6]. One approach to improving theluminescence efficiency of Tm3+ is to co-dope it withother rare-earth ions[7]. The choice of host materials is avery important factor to obtain high efficient upconver-sion emission. In this case, the main goal of the c…     

Intense frequency upconversion fluorescence of Er~(3+)/Yb~(3+) co-doped lithium-strontium-lead-bismuth glasses

Infrared-to-visible upconversion fluorescence of Er3+/Yb3+ co-doped lithium-strontium-lead-bismuth (LSPB) glasses for developing potential upconversion lasers has been studied under 975-nm excitation. Based on the results of energy transfer efficiency and upconversion spectra, the optimal Yb3+-Er3+ concentration ratio is found to be 5:1. Intense green and red emissions centered at 525, 546, and 657 nm, corresponding to the transitions 2H11/2→4 I15/2, 4S3/2→4 I15/2, and 4F9/2→4 I15/2, respectively, were observed. The quadratic dependence of the 525-, 546-, and 657-nm emissions on excitation power indicates that a two-photon absorption process occurs under 975-nm excitation. The high-populated 4I11/2 level is supposed to serve as the intermediate state responsible for the upconversion processes. The intense upconversion luminescence of Er3+ /Yb3+ co-doped LSPB glasses may be a potentially useful material for developing upconversion optical devices.     

Upconversion fluorescence spectroscopy of Er~(3+)-doped lead oxyfluorosilicate glass

Upconversion fluorescence emission of Er3+-doped oxyfluorosilicate glass excited at 975 nm is experimentally investigated. The results reveal that the intense green and red emission, and weak blue emission centered at 525, 543, 655, and 410 nm, respectively. A two-photon upconversion process is assigned to the green and red emission while a three-photon process is responsible for blue upconversion. The possible upconversion mechanisms are discussed based on excited state absorption and energy transfer between excited Er3+ ions. The intense upconversion fluorescence of Er3+-doped lead oxyfluorosilicate glass may be a potentially useful material for developing upconversion optical devices.     

High Efficiency Infrared to Visible Upconversion in Er3＋／yb3＋—Doped Lead Halide Tellurite Glass

Strong upconversion luminescence of Er3 /Yb3 -doped lead halide tellurite glass under 976nm excitation is demonstrated. Three emission bands centred at 525 nm, 545 nm, and 655 nm resulting from the transitionsfrom the excited states 2H11/2, 4S3/2, and 4F9/2 to the ground state 4I15/2, respectively, are observed evenat 60mW pumping power. The power dependent intensity and the upconversion mechanisms responsible forthe luminescence are evaluated and discussed. The obtained results might provide useful information for thedevelopments of upconversion lasers.     

Spectroscopic Properties of Yb^3＋-doped Germano-Silicate Glasses

We investigate the absorption, stimulated emission cross section and potential laser parameters of Yb^3 doped gernano-silicate glasses (GSY glass). The emission cross section is evaluated by using the measured absorption spectra and the principle of reciprocity. It is found that Yb^3 in GSY glasses has high stimulated emission cross section of 0.5-0.65pm^2 near 1020nm and exists long measured fluorescence lifetime of 1.20-2.00ms. Compared with other glass hosts, the GSY glass exhibits excellent general spectroscopic properties for Yb^3 -doped double-cladding fibres.     

Yb3+掺杂铝氟磷酸盐玻璃的光谱和激光性能

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后处理对离子交换磷酸盐玻璃平面光波导的影响

研究了退火和二次离子交换对Er3+/Yb3+共掺的磷酸盐玻璃平面光波导传输特性的影响。在退火过程中，由于热效应和波导层Ag+离子的浓度差使得Ag+离子重新分布；随着退火时间的延长和温度的升高，光波导模式数目逐渐增加，波导层深度加深，且波导表面折射率与玻璃基质折射率差减小，退火扩散深度与退火时间的平方根成正比。电子探针结果显示在二次离子交换后形成了掩埋式的光波导，Ag+离子浓度接近二次方分布，而掩埋式的光波导有助于降低光波导的传输损耗。