Qiuhong Yang

Spectroscopic properties and near-infrared broadband luminescence of Bi-doped SrB4O7 glasses and crystalline materials.

Spectroscopic properties of Bi-doped SrB(4)O(7) glasses, sintered compounds, polycrystalline materials, and single crystals were investigated. Broadband near-infrared luminescence was realized in Bi-doped SrB(4)O(7) glasses with basicity and polycrystalline materials with non-bridging oxygens. In Bi:SrB(4)O(7) single crystals, only visible luminescence of Bi(3+) and Bi(2+) was observed, but no near-infrared. The rigid three-dimensional network of SrB(4)O(7) crystal is proved to be unfavorable for accommodation of Bi(+) ions.

Synthesis and luminescence characterization of cerium doped Lu2O3-Y2O3-La2O3 solid solution transparent ceramics

Ce3+:(Lu0.7Y0.25La0.05)2O3 transparent ceramics were fabricated with nanopowders and sintered in H2 atmosphere. The spectral properties of Ce3+:(Lu0.7Y0.25La0.05)2O3 transparent ceramics were investigated and the luminescence of Ce3+ in the solid solution of Lu2O3, Y2O3 and La2O3 has been found. The ceramics has high density of 8.10 g/cm(3) and short fluorescence lifetimes of 7.15 ns and 26.92 ns. It is expected to be a good fast response high temperature inorganic scintillating materials.

Spectral Properties of Er3+/Tm3+ Co-Doped ZBLAN Glasses and Fibers

A series of Er3+/Tm3+ co-doped fluoride (ZBLAN) glasses and fibers was prepared and their fluorescence spectra was measured under excitation at 793 nm and 980 nm. Correlation between the self-absorption effect of rare-earth ions and the shift of the emission peak was investigated. With the increasing length of fiber, the emission peaks red-shift when self-absorption occurs at the upper level of emission transition or blue-shift when that occurs at the lower level. As a result of the strong self-absorption effect, Er3+/Tm3+ co-doped fibers mainly yield 1390–1470, 1850–1980, and 2625–2750 nm emissions when excited at 793 nm, and 1480–1580, 1800–1980, and 2625–2750 nm emissions when excited at 980 nm. Further, a broadband emission in the range of 1410–1580 nm covering the S + C communication band was obtained by the dual-pumping scheme of 793 nm and 980 nm. Results suggest that the dual-pumping scheme would be more effective and important for an Er3+/Tm3+ co-doped fiber amplifier working in the S + C communication band.

Optical and thermoluminescence properties of Lu2Si2O7:Pr single crystal

Single crystal of Lu2Si2O7:Pr was grown by Czochralski method. Transmittance, photoluminescence excitation (PLE) and photo- luminescence (PL) spectra, X-ray excited luminescence (XEL) and fluorescence decay time spectra of the sample were measured and dis- cussed to investigate its optical characteristics. The crystal structure of the as grown Lu2Si2O7:Pr was confirmed to be C2/m. There was a broad absorption peaking at 245 nm in the region from 200-260 nm. The PL spectrum was dominated by fast 3 PJ� 3 HJ band peaking at 524 nm. The XEL spectrum was dominated by the fast 5d 1 4f 1 �4f 2 emission peaking at 265 nm. The 2D (temperature-intensity) and 3D (tem- perature-wavelength-intensity) thermally stimulated luminescence (TSL) spectra were measured. The Pr 3+ ion was found to be the recombina- tion center during the TSL process. Three obvious traps were detected in LPS:Pr single crystal with energy depth at 1.06, 0.78 and 0.67 eV.

Laser operation in Nd:Sc 2 SiO 5 crystal based on transition 4 F 3/2 → 4 I 9/2 of Nd 3+ ions

Laser operation based on energy transition 4F3/2→4I9/2 of Nd3+ ions in 1at.% Nd:Sc2SiO5 (Nd:SSO) crystal is reported. By using output coupler of Toc = 2.5% and 808 nm laser diode pump source, laser operation at 914 nm was preliminarily obtained with output power of 581 mW.

Spectroscopic Characteristics and Laser Performance of

(Nd_xY_0.9-xLa_0.1)₂O₃ (x=0.005-0.04) transparent ceramics were fabricated by conventional solid-state processing. The radiative spectral properties of the ceramic samples were evaluated by fitting the Judd-Ofelt model with the absorption and emission data. (Nd_xY_0.9-xLa_0.1)₂O₃ ceramics have broad absorption and emission bands with a radiative decay time of 328 μs. The absorption cross section at 806 nm and stimulated emission cross section at 1078 nm are calculated to be 1.53 ×10^-20 and 5.22 × 10^-20 cm², respectively. The product of quantum efficiency and the ionic concentration (ηN) exhibited a peak value at 1.5 at% Nd³⁺ ion concentration, while the lifetime decreases dramatically from 300 μs (0.5 at% Nd) to 49 μs (4.0 at% Nd). With 1.0 at% Nd:Y_1.8La_0.2O₃ ceramics acting as a laser medium, continuous-wave output power of 1.03 W was obtained at 1079.5 nm under an absorbed pump power of 7.2 W, corresponding to a slope efficiency of 18.4%.

{\rm Nd}{:}{\rm Y}_{1.8}{\rm La}_{0.2}{\rm O}_{3}

Highly transparent Yb, Ho doped (YLa)(2)O-3 ceramic was fabricated by conventional ceramic processing with nanopowders. The absorption and emission spectra of the ceramic was investigated. The energy transfer mechanism between Yb3+ and Ho3+ was also discussed. The strong emission band around 2 mu m indicated that the Yb-Ho: (Y(0.9)0La(0.10))(2)O-3 transparent ceramic is a promising gain medium for the generation of 2 mu m laser emissions. The laser operation of Yb-Ho co-doped (YLa)(2)O-3 ceramic at 2.1 mu m is first reported.

Transparent Ceramics

Lu2Si2O7 (LPS) single crystals doped with 0.05%Ce and co-doped with 0.05%Ce, 0.05%Pr were grown by floating zone method. The segregation coefficients of Pr and Ce in LPS host were estimated through ICP-OES method. The VUV-UV excitation and emission spectra at 150 K, X-ray excited luminescence, fluorescence decay time of Ce3+ emission at room temperature and thermally stimulated luminescence (TSL) spectra of LPS:Ce and LPS:Ce,Pr were measured. The energy transfer from Pr3+ to Ce3+ in LPS host was observed through the VUV-UV spectra and possible transfer pathways are discussed. The luminescence intensity of Ce3+ can be improved by about 20% after Pr3+ co-doping. Defects in LPS host are studied through TSL spectra.

Spectral and laser properties of Yb and Ho co-doped (YLa)2O3 transparent ceramic

通过浮区法制备得到LPS:0.5%Ce单晶样品, 并对其包裹体、开裂、闪烁和光学性能进行了研究,获得了晶体的电子探针谱、透过谱、77~500 K下的紫外激发发射谱、X射线激发发射谱和77~500 K下的衰减时间谱。研究发现晶体中存在解理开裂和热应力开裂, 同时存在两种类型的包裹体, 分别包含[Si 3 O 9 ] 6- 、阴离子团和过量的SiO 2 。由于采用空气为生长气氛, 样品中部分Ce 3+ 被氧化为Ce 4+ 。浮区法LPS:0.5%Ce表现出较高的发光效率, 约为32000 ph/MeV。随着温度的升高, 样品的紫外激发发射谱逐渐向长波方向移动, 发射谱谱线随着温度的升高展宽, 导致自吸收的增加。衰减时间的温度转变点位于450 K, 表明LPS:Ce闪烁晶体适用于高温环境, 是一种性能优异的闪烁晶体。通过浮区法制备得到LPS:0.5%Ce单晶样品, 并对其包裹体、开裂、闪烁和光学性能进行了研究,获得了晶体的电子探针谱、透过谱、77~500 K下的紫外激发发射谱、X射线激发发射谱和77~500 K下的衰减时间谱。研究发现晶体中存在解理开裂和热应力开裂, 同时存在两种类型的包裹体, 分别包含[Si 3 O 9 ] 6- 、阴离子团和过量的SiO 2 。由于采用空气为生长气氛, 样品中部分Ce 3+ 被氧化为Ce 4+ 。浮区法LPS:0.5%Ce表现出较高的发光效率, 约为32000 ph/MeV。随着温度的升高, 样品的紫外激发发射谱逐渐向长波方向移动, 发射谱谱线随着温度的升高展宽, 导致自吸收的增加。衰减时间的温度转变点位于450 K, 表明LPS:Ce闪烁晶体适用于高温环境, 是一种性能优异的闪烁晶体。

Energy Transfer and Defects Study in

The effects of Nd3+ concentration on the visible fluorescence spectroscopic properties of Nd:(Y0.9La0.1)2O3 transparent ceramics are investigated. Under 270 nm excitation, three emission peaks are observed at 396, 426, and 633 nm. When the Nd3+ concentration is increased, intensities of the peaks at 396 and 426 nm increase while the 633 nm peak become weak due to the fluorescence re-absorption effect. Broad luminescence band centered at 426 nm is observed from the fluorescence spectrum stimulated at 358 nm. The emission intensity increases with the increase of Nd3+ ion content firstly, then decreases owing to the concentration quenching of Nd3+ ions.