Luminescence Spectra of YGG：RE^3＋, Bi^3＋ （RE = Eu and Tb） and Energy Transfer from Bi^3＋ to RE^3＋

We investigate the luminescence properties of Bi^3＋ and RE^3＋ （RE = Tb or Eu） in a Y3Ga5O12 （YGG） host system. The additional doping of Bi^3＋ can enhance the luminescence of Th^3＋ or Eu^3＋ in this host. Energy transfer from Bi^3＋ to Tb^3＋ and Eu^3＋ is observed and the mechanism of energy transfer is investigated. Mechanism of energy transfer can be explained as electric multipole interaction since the Bi^3＋ emission band and Tb^3＋ or Eu^3＋ excitation band overlaps and the Bi^3＋ emission intensity decreases while the intensity of Tb^3＋ or Eu^3＋ increases with the increase of Tb^3＋ or Eu^3＋ concentration. Therefore, Bi^3＋ ion is a kind of efficient sensitizer to the Tb^3＋ and Eu^3＋ activators in the Y3Ga5O12 host.     

罗丹明-三嗪荧光探针对Al3+和Cr3+的识别

用罗丹明B乙二胺分步取代三聚氯氰环上两个氯原子,得到对称结构的罗丹明-三嗪衍生物。在pH 4～6的乙醇溶液中,衍生物能选择性识别Al3+和Cr3+,荧光发射和紫外-可见吸收显著增强。衍生物对Al3+ 和Cr3+识别不受共存金属离子干扰。在一定条件下,可作为高选择性和高灵敏的Al3+或Cr3+荧光和比色增强型光谱探针。     

螺吡喃光响应的汞、铬、银离子探针及相互作用光谱

合成并表征了1-羟乙基-3,3-二甲基-6′,8′-二叔丁基吲哚啉苯并螺吡喃配体1及其衍生物配体2。由于苯并螺吡喃6′,8′-二叔丁基斥电子基团的电子效应,开环体部花菁酚氧负离子上的负电荷难以分散,使其结构不稳定,配体1在紫外光照射下不直接开环,只有在极性较强的甲醇溶剂中受适当金属离子诱导才能形成有色开环体部花菁结构形式。配体1能较好地选择识别Hg2+,Cr3+和Ag+。当其相互作用时,不但紫外可见光谱及荧光光谱有明显“turn-on”变化,而且体系颜色明显地由无色变成黄色,目视识别效果直观明显。其他金属离子的存在对Ag+,Cr3+和Hg2+的识别几乎没有干扰。配体1与Ag+,Cr3+和Hg2+络合的化学计量比均为1∶1,检出限分别是：7.435 8×10-6, 6.126 8×10-6, 3.452 4×10-6 mol·L-1。通过配体2进一步证明了配体1和金属离子识别的结合模式。即螺吡喃结构中N1位取代侧链上的羟基,和其开环体酚氧负离子相互协调并与金属离子结合。     

Effects of Yb^3＋ in Er^3＋/Yb^3＋ Codoped Fluorophosphate Glasses

For the Er^3＋ /Yb^3＋ codoped fluorophosphate glasses, Judd-Ofelt theory is used to analyse the influence of YbF3 as not a sensitizer but an average component on the spectroscopic properties around 1530nm emission. The double roles of Yb^3＋, as a sensitizer and as an average component, are discussed. It is found that Yb^3＋ as an average component contributes to the increase of fluorescence lifetime, and Yb^3＋ as a sensitizer has the best sensitization when its concentration is 2.4 mol%.     

Characteristics of Cladding-Pumped Short Er3+/Yb3+ Codoped Single Mode Phosphate Glass Fibre

We experimentally investigate the laser characteristics of a series of short pieces of newly-developed Er³⁺/Yb³⁺ codoped single mode phosphate glass fibres via the cladding pump of a 976nm multimode laser diode. A stablecontinuous-wave single transverse mode laser with over 85mW at 1553nm is generated from a 5.5-cm-long active fibre. Single mode laser output power per unit length is up to 15mW/cm. Moreover, the slope efficiency is 11.8% when the pump power is below 940mW and the 3dB linewidth is 0.06nm at the maximum pump power. The numerical simulation results show that the laser emission slope efficiency can exceed 20% by means of increasing the coupling efficiency of the pump to the fibre core further.     

双包层Er3+/Yb3+共掺光纤激光器动态特性的分析

分析了弛豫振荡前上能级Er³⁺、Yb³⁺粒子数的变化和弛豫振荡时Er³⁺上能级粒子数的变化情况以及弛豫振荡时激光功率的变化规律,结果表明:弛豫振荡时的激光峰值功率远大于稳态时的激光功率.     

Efficient Fibre Amplifiers Based on a Highly Er3＋/Yb3＋ Codoped Phosphate Glass-Fibre

Highly Er3＋ /yb3＋-codoped single-mode phosphate glass fibre is fabricated by the rod-in-tube technique. The performances of high-concentration Er3＋ /yb3＋-codoped phosphate glass fibre amplifiers are investigated and discussed. An efficient optical fibre amplifier with a gain of 12.6 dB based on a 3.0 cm long Era＋ /ybe＋-codoped phosphate glass fibre is demonstrated under a dual-pump configuration with two 976 nm fibre-pigtail laser diodes, which make it attractive for compact Er3＋-doped fibre amplifiers. The obtedned noise figures of signal wavelength from 1525 to 1565nm are less than 6.0dB. Gain saturation behaviour at 1535nm is also investigated, and the obtained saturation output power is larger than 10 dBm.     

Er^3＋ and Yb^3＋ Codoped Phosphate Laser Glass for High Power Flashlamp Pumping

A novel yb^3＋-Er^3＋ codoped phosphate glass for high power flashlamp pumping and high repetition rate laser at 1.54μm, designated EAT5-2, is developed. The weight-loss rate of is 1.3 × 10^-5 gcm^-2h^-1 in boiling water, which is comparable to Kigre＇s QX-Er glass. Some spectroscopic parameters are analysed by Judd-Ofelt theory and McCumber theory. The emission cross section is calculated to be 0.73 × 10^-20 cm^2. The thermo-mechanical properties of EAT5-2 are modified after an ion-exchange chemical strengthening process in a KNO3/NaNO3 molten salt bath. The thresholds for optical damage from the flashlamp pumping are tested on glass rods. A repetition rate of 15 Hz is achieved for chemically strengthened glass. The laser experimental results at 1.54 μm from flashlamp pumping are also reported.     

LaOBr:Tb3+，Dy3+的发光特性及高压研究

 采用高温常压方法合成了稀土发光材料LaOBr:Tb³⁺，Dy³⁺，采用高温高压方法对材料进行了处理，研究了高温高压处理前后样品发光特性的变化，并进行了发光衰减测量。结果表明，Dy³⁺的掺杂可以将Tb³⁺的⁵D₃能级的激发能有效地驰豫到⁵D₄能级，从而使⁵D₄~⁷F_J（J＝0, 1,…,6）的发射，尤其是⁵D₄~⁷F₅的发射明显增强，使得样品的发光亮度大大提高。Dy³⁺，Tb³⁺间存在交叉驰豫共振能量传递。高压处理过程引入的杂质、材料氧化及压致晶场变化都对材料的发光特性产生影响。     

Cooperative Quantum Cutting of Nano-Crystalline BaF2：Tb^3＋, Yb^3＋ in Oxyfluoride Glass Ceramics

We report on cooperative quantum cutting in Tb^3＋- Yb^3＋ codoped glass ceramics. Precipitation of BaF2 nanocrystals is confirmed by XRD and HRTEM analysis. Near-infrared emission due to transition of Yb^3＋ ions under 485 nm excitation indicates cooperative energy transfer from Tb^3＋ to Yb^3＋. The quantum efficiency of this process reaches 145%. The realization of quantum cutting in glass ceramics may have promising applications in solar cells.     

Intrinsic Bistability and Critical Slowing in Tm^3＋/Yb^3＋ Codoped Laser Crystal with the Photon Avalanche Mechanism

We present theoretically a novel intrinsic optical bistability （IOB） in the Tm^3＋ /Yb^3＋ codoped system with a photon avalanche mechanism. Numerical simulations based on the rate equation model demonstrate distinct 10B hysteresis and critical slowing dynamics around the avalanche thresholds. Such an 10B characteristic in Tm^3＋ /Yb^3＋ eodoped crystal has potential applications in solid-state bistable optical displays and luminescence switchers in visible-infrared spectra.     

Er3+/Yb3+ Codoped Phosphate Glass Fibre with Gain per Unit Length Greater Than 3.0dB/cm

We experimentally study a novel fibre with high gain per unit length based on the homemade erbium--ytterbium codoped phosphate glass. The gain and noise characterizations with different pump powers at different wavelengths are investigated. The 1.8-cm-long fibre, dual-pumped by two single mode 980-nm fibre-pigtailed laser diodes, provides a gain per unit length greater than 3.0dB/cm and a noise figure less than 6.5dB. The gain saturation behaviour at 1535nm is obtained and the saturation output power (3dB compression) is greater than 5dBm.     

Er3+/Yb3+共掺TeO2-Li2O-B2O3-GeO2玻璃系统的光谱性质和热稳定性研究

制备了Er³⁺/Yb³⁺共掺的70TeO₂-5Li₂O-(25-x)B₂O₃-xGeO₂（x=0,5,10,15,20 mol%）系列玻璃, 研究了玻璃的热稳定性能, 测试了玻璃的吸收光谱、荧光光谱以及Er3+离子4I13/2能级荧光寿命, 并根据McCumber理论计算了Er³⁺离子4I13/2→4I15/2跃迁的受激发射截面. 结果表明：随着GeO₂含量的增加, 玻璃的热稳定性逐渐提高, 荧光谱线半高宽（FWHM）保持在70 nm左右, 而荧光强度和Er3+离子4I13/2能级荧光寿命逐渐提高, 研究表明这种玻璃系统是一种具有应用潜能的宽带光纤放大器用的基质材料.     

Interaction of O3+ Ions with Al2O3 Nanocapillaries

We investigate angular distributions of the transmitted 60 keV and 120 keV O^3＋ ions through nanocapillaries with 50hm diameter and 10μm length. The experimental results are in agreement with the ＇guiding effect＇ found by Stolterfoht et al. For different tilted angles of the nanocapillary membrane with respect to the beam, the angular distributions of the transmitted ions are measured by a one-dimensional micro-channel plate （MCP） detector. Moreover, the dependence of this guiding effect on the projectile energy is studied.     

Photoassociation Reactions H＋D^＋ and H^＋ ＋D in Ultrashort Pulse Laser Fields

The photoassociation reactions H＋D^＋ and H＋ ＋D induced by the one- and two-colour laser pulses are theoretically studied. The reactions occur through two channels： （i） H（1S）＋D^＋ →HD^＋, and （ii） H^＋ ＋D（1S）→HD^＋. The reaction probability through channel （ii） is higher than through channel （i）. The populations of the products H^＋ ＋D and HD＋ and the ratio of H^＋ ＋D to HD＋ can be controlled by laser pulses. The two-colour laser pulses can more efficiently lower the dissociation probability and therefore enhance the yield ratio of the product HD＋.     

Self-Starting Passively Mode-Locked Er^3＋/Yb^3＋ Codoped Phosphate Glass All-Fibre Ring Laser

A self-starting, passively mode-locked all-fibre ring laser based on the homemade Er^3＋/Yb^3＋ codoped phosphate glass fibre is reported. Dual-pump sources were used to achieve the mode-locked operation in the experiment. The fundamental mode-locked pulse repetition rate is 10.67MHz. The pulse duration, assumed as the fit of hyperbolic secant pulse shape, is 5.82ps. We also observe the multi-pulse output of the fibre laser.     

Relativistic Energies and Auger Widths of High-Lying Doubly-Excited States 1s^23lnl′ ^1De in Be-Like O^4＋ Ions

The saddle-point variational method and restricted variational method are used to calculate energies of doublyexcited singlet states 1s^23lnl′ （n =3-.） ^1 De in Be-like O^4＋ ions, including the mass polarization and relativistic corrections. The saddle-point complex-rotation method is used to compute the Auger widths and Auger transition rates. These results are compared with other theoretical and experimental data in the literature.     

连续波锁模Pr3+:YLF激光器

本文报导了采用氩离子激光器来泵浦Pr³⁺:YLF晶体,应用声光调制器实现了主动锁模;同时应用振动─高反射平面镜也实现了被动锁模,两种锁模均得到了ps光脉冲.据作者了解这是这种晶体材料的第一次锁模运转.     

Sol-gel法制备Er3+-Yb3+共掺杂Al2O3粉末光致发光特性

采用异丙醇铝[Al(OC₃H₇)₃]为前驱体,溶胶-凝胶(Sol-gel)法制备Er³⁺-Yb³⁺共掺杂Al₂O₃粉末.实验结果表明:900 ℃烧结的粉末为固溶Er³⁺、Yb³⁺的γ-(Al,Er,Yb)₂O₃相和少量θ-(Al,Er,Yb)₂O₃相的混合物.Er³⁺-Yb³⁺共掺杂Al₂O₃粉末具有中心波长为1.533 μm的光致发光(PL)特性.1 mol % Er³⁺和1 mol% Yb³⁺共掺杂的Al₂O₃粉末的PL强度较1 mol % Er³⁺掺杂提高2倍,半峰宽从53 nm增加到63 nm.随泵浦功率的提高,PL强度呈线性增加后渐呈饱和趋势.     

Ab Initio Calculations of Differential Cross Sections for Single Charge Transfer in ^3He^2＋ ＋ ^4He Collisions

The single charge transfer process in ^3He^2＋ ＋ ^4He collisions is investigated using the quantum-mechanical molecular- orbital close-coupling method, in which the adiabatic potentials and radial couplings are calculated by using the ab initio multireference single- and double-excitation configuration interaction methods. The differential cross sections for the single charge transfer are presented at the laboratorial energies E = 6 keV and lOkeV for the projectile ^3He^2＋. Comparison with the existing data shows that the present results are better in agreement with the experimental measurements than other calculations in the dominant small angle scattering, which is attributed to the accurate calculations of the adiabatic potentials and the radial couplings.