独居石微晶玻璃中玻璃相含量的红外光谱定量测定

独居石微晶玻璃由偏磷酸盐玻璃和独居石两相组成。玻璃和独居石的红外吸收谱带彼此不相重叠,且1275和616cm~(-1)谱带的吸收强度随玻璃相的含量变化而变化。两谱带的对数吸光度比值与玻璃相含量(w％)的相关系数r=0.9975,其回归方程为y=48.356 25.93x。合成独居石的IR谱中952和616cm~(-1)谱带的吸光度比值也随不同的Ce_2O_3/La_2O_3比值规律变化。其r=0.9917,回归方程为y=0.2211exp(0.0221x)。高的相关性表明IR技术可在磷酸盐微晶玻璃物相定量分析中得到实际应用。     

掺铒铋酸盐玻璃的光谱性质和热稳定性研究

测试了铋酸盐玻璃(85-x)Bi2O3-(10+x)B2O３-5Na2O(x=0，5，10，15，20，25 mol%)中Er3+离子的吸收光谱、荧光光谱、荧光寿命及热稳定性.应用Judd-Ofelt理论计算了铋酸盐玻璃中Er3+离子的强度参数(Ω2=(352—386)×10-20cm2,Ω4=(138—152)×10-20cm2,Ω6=(093—117)×10-20cm2),应用McCumber理论计算了Er3+离子的受激发射截面(σe=(70—95)×10-21cm2)及Er3+离子4I13/2→4I15/2发射谱的荧光半高宽(FWHM=57—79nm)，测得了Er3+离子４I13/2能级荧光寿命(τm=265—159ms)，分析了玻璃的热稳定性能.研究了Er3+离子各种光谱参数对成分的依赖性，发现随着玻璃中B2O3含量的增加，强度参数Ωt(t=2,4,6)、荧光半高宽(FWHM)、热稳定性均相应增加，而测得的荧光寿命却减小.比较了不同基质玻璃中Er3+离子的光谱特性，结果表明掺铒铋酸盐玻璃更适合于掺Er3+光纤放大器实现宽带和高增益放大. 关键词： 铋酸盐玻璃 光谱性质 成分依赖性 Er3+离子     

具有高机械强度的掺Er3+∶TeO2-Nb2O5玻璃的光谱性质研究

熔制了掺铒碲铌玻璃样品(100-XTeO2-XNb2O5(X=5,10,15,20 mol%),测试了其密度、折射率、转变温度、析晶温度、维氏机械强度、吸收光谱、荧光光谱、荧光寿命等参量。利用Judd-Ofelt和McCumber理论分别计算了铒离子强度参量Ωt (t=2, 4, 6)和受激发射截面σemi的大小,研究了掺铒碲铌玻璃样品光谱参量对Nb2O5成分的依赖性,并与典型的碲锌钠玻璃（75TeO2-20ZnO-5Na2O）在热学、机械强度、光谱性质和放大品行四个方面进行了比较.     

掺铒碲-钨-钠玻璃基质的光谱性质研究

制备了用于离子交换法制备光波导器件的掺铒碲-钨-钠玻璃基质。应用扎得-奥菲而特(Judd—Ofelt)理论计算了玻璃样品的三个强度参量,由强度参量计算了Er^3 离子的自发跃迁几率、荧光分支比等光谱参量;应用麦克库玻(McCumber)理论,计算了Er^3 离子在1．5μm的受激发射截面,荧光测试发现Er^3 离子的荧光半峰全宽可达65nm。比较了Er^3 离子在不同玻璃基质中的光谱特性。结果表明,Er^3 离子在碲-钨-钠玻璃中具有较高的受激发射截面和较宽的荧光半峰全宽,可以用于宽带光波导器件的制备。     

掺钕镉铝硅酸盐玻璃的Judd-Ofelt理论分析与光谱特性

以掺杂光子晶体光纤为介质的光纤激光器一直受到科研工作者的广泛关注,应用于光子晶体光纤纤芯的掺稀土元素玻璃的制备成为研制掺杂光子晶体光纤的关键问题。利用高温熔融工艺制备钕离子掺杂的40SiO_2-14Al_2O_3-(40-x)CdO-2Li2O-2K2O-2Na_2O-xNd_2O_3(x=0.07,0.14,0.21,0.35,0.42,0.56mol)重金属硅酸盐玻璃系统,测试了其吸收光谱和荧光光谱。采用Judd-Ofelt理论,计算了玻璃样品的强度参数Ωt(t=2,4,6)以及钕离子的自发辐射概率、荧光分支比、荧光辐射寿命等参数。利用测得的荧光光谱计算了钕离子能级跃迁4 F3/2→4 I11/2的受激发射截面及荧光有效线宽。结果表明:当掺Nd_2O_3的摩尔分数为0.42时,制备的镉铝重金属硅酸盐玻璃具有较大的受激发射截面和比较宽的荧光有效线宽,且与相关文献中的钕离子掺杂玻璃相比,具有良好的激光性能和增益性能,有望在研制掺杂光子晶体光纤中得到应用。     

Nd3+离子掺杂氧化物玻璃的光谱性质

高温熔融法制备了69.5B2O3-20Li2O-(10-χ)CaO-χPbO-0.5Nd2O3(χ=1,3,5,7,mol%)和68.5Li2O-(29-φ)CaO-φAl2O3-2La2O3-0.5Nd2O3(φ=3,7,10,15,mol%)玻璃,测量了玻璃样品的吸收和发射光谱(800nm激光二极管激发),从吸收光谱出发,应用Judd-Ofelt理论获得了Nd3+光学跃起的强度参数。根据强度参数和发射光谱,计算了Nd3+离子4F3/2→4I11/2跃迁的荧光发射截面σe。结果显示,在B2O3-Li2O-CaO-PbO-Nd2O3系统中随着CaO的减少和PbO的增加,Nd3+离子的强度参数Ω2增大,表明样品的对称性降低;强度参数Ω6也增大,说明玻璃样品中Nd-O键的共价性和键强降低;同时,Nd3+离子4F3/2→4I11/2跃迁的荧光发射截面σe的大小和荧光强度都减小。在Li2O-CaO-Al2O3-La2O3-Nd2O3系统中,随着CaO的减少和Al2O3的增加,Nd3+离子的强度参数Ω2减小,说明样品的对称性增加;强度参数Ω6减小,说明玻璃样品中Nd-O键的共价性和键强增强;同时,Nd3+离子4F3/2→4I11/2跃迁的荧光发射截面的大小和荧光强度也都减小。     

ZnNb2-xTaxO6（x=0～2.0）材料电子结构与光学性质的第一性原理计算

采用基于密度泛函理论的赝势平面波第一性原理方法,理论研究了不同计量Ta掺入ZnNb2O6材料的光电特性。通过对ZnNb2-xTaxO6(x=0~2.0)材料键结构和态密度的计算,并结合带间电子跃迁分析了材料的介电函数、折射率、反射率以及吸收系数。计算结果显示:(1)ZnNb2-xTaxO6(x=0~2.0)为间接半导体,带隙随着Ta原子的掺入呈下降趋势(x=0,Eg=3.51eV;x=2,Eg=2.916eV),随着Ta掺入量的增加导带顶逐渐移向费米面。态密度主要由O2p、Zn3d、Nb4d、Ta5d轨道组成;(2)ZnNb2-xTaxO6(x=0~2.0)价电子态呈现为非对称,具有很强的局域性,对材料整体的电子结构和键特性有重要的影响;(3)介电函数的计算表明,ZnNb2-xTaxO6(x=0~2.0)材料各向异性,最大吸收峰在3.02×105cm-1附近,消光系数在带边表现出较强的吸收特性,进一步以带结构和态密度为出发点,探讨了电子带间跃迁的光电机理。该结果为研制高性能光电器件用新型功能材料提供了理论依据。     

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。     

Er3+掺杂的锗铋酸玻璃光谱性质的研究

制备了一种新型掺Er3 锗铋酸盐玻璃。分析了吸收光谱和上转换荧光光谱,并应用Judd-Ofelt理论计算了锗铋酸盐玻璃的3个强度参量tΩ(t=2,4,6),分别为Ω2=3.35×10-20cm2,Ω4=1.34×10-20cm2以及Ω6=0.67×10-20cm2。研究了在两种不同的激发光下(980和808 nm)锗铋酸盐玻璃的发光机制。根据McCumber理论,分析了在1.55μm光通讯窗口的光谱性质,计算了能级4I13/2→4I15/2跃迁的受激发射截面,结果显示掺Er3 锗铋酸盐玻璃具有较宽的荧光半高宽和较大的受激发射截面。因此有希望成为高效的上转换发光材料和1.55μm光通讯材料。     

Spectroscopic properties of Yb~(3+)-doped TeO_2–BaO–BaF_2–Nb_2O_5-based oxyfluoride tellurite glasses

A series of oxyfluoride glasses with the compositions of 75 mol% TeO2, 10 mol% Nb2O5,(15 mol%-x) BaO, x BaF2(x = 0 mol%, 5 mol%, 10 mol%, 15 mol%) doped with Yb2O3 were prepared by the melt-quenching method. Their emission cross-sections, fluorescence lifetimes, and gain properties were investigated by using the absorption spectra and the fluorescence decay curves. The results show that by substituting BaF2 for BaO, the emission cross-section decreases from 1.37 pm2 to 1.21 pm2, and the fluorescence lifetime increases from 0.71 ms to 0.96 ms. These properties indicate that this oxyfluoride tellurite glass may have potential uses as the Yb2O3-doped gain medium in a solid laser.     

新型GeSe2-In2Se3-AgI玻璃性能研究

采用传统熔融-淬冷法制备了一系列新型(100-x)(4GeSe2-In2Se3)-xAgI(x=20,30,40mol%)硫系玻璃样品.利用X射线衍射分析、差热分析、可见-近红外吸收光谱、红外透过光谱、喇曼分析等技术手段研究了该玻璃系统的组成、结构、热稳定性和光学特性等.利用Tauc方程计算出了样品的间接带隙;测试了部分样品在不同升温速率下的差示扫描量热曲线,并采用Kissinger法计算了玻璃样品的析晶活化能.X射线衍射数据表明,该玻璃体系在较宽的组分范围内有良好的非晶特性,成玻范围较宽;差热分析和析晶动力学研究表明,玻璃样品70(4GeSe2-In2Se3)-30AgI具有较好的热稳定性(ΔT=114℃)和较高的活化能(Ea=320.4kJ/mol).随着AgI含量的增加,玻璃的短波吸收限蓝移,并且光学带隙有增大的趋势.此外,红外透过光谱分析表明该玻璃体系具有良好的红外透过性能,其红外截止波长不会随着AgI含量的增加而发生明显变化,皆为16μm左右.     

偏磷酸根(PO-3)对氟铝酸盐玻璃透光性能影响

在氟铝酸盐玻璃（AMCSBY）中引入Ba(PO3）2替代BaF2,替代公式为10MgF2-20CaF2-(10-x)BaF2-10SrF2-15YF3-35AlF3-xBa(PO3)2(x=,2,4,6,8)。对玻璃进行了差热分析，结果表明，在氟铝酸盐玻璃中引入偏磷酸盐使玻璃形成能力大大提高；测量了玻璃从紫外到红外的透过光谱和紫外吸收光谱，在玻璃中引入偏磷酸钡使玻璃中红外透过能力下降，红外吸收边带移向短波段，玻璃紫外透过能力得到提高。紫外吸收边带移向紫外波段，由于PO3^-的影响，O－H吸收峰由2830nm移到3145nm。     

Evidence of spin glass dynamics in dilute LiHoxY1-xF4

ac susceptibility measurements are presented on the dilute, dipolar coupled, Ising magnet LiHoxY1-xF4 for a concentration x=0.045. The frequency and temperature dependences of the susceptibility show characteristic glassy relaxation. The absorption spectrum is found to broaden with decreasing temperature suggesting that the material is behaving as a spin glass and not as an exotic spin liquid as was previously observed. A dynamical scaling analysis suggests a spin glass transition temperature of 43+/-2 mK with an exponent znu=7.8+/-0.2.     

Theoretical Study of Collision-Induced Double Transitions in CO(2)-X(2) (X(2) = H(2), N(2), and O(2)) Pairs

The double vibrational collision-induced absorptions CO(2) (nu(3) = 1) + X(2) (nu(1) = 1) <-- CO(2) (nu(3) = 0) + X(2) (nu(1) = 0), for X(2) = H(2), N(2), and O(2) are studied on the basis of quantum lineshapes computed using isotropic potentials and dipole-induced dipole functions. The linestrengths and energies of the vibration-rotation transitions are treated explicitly for X(2) and utilizing the HITRAN database for CO(2). From the frequency-dependent absorption profiles, the integrated absorption intensities are determined to be 7.2 +/- 1.2, 1.2 +/- 0.1, and 1.1 +/- 0.2 (10(-4) cm(-2) amagat(-2)) for the H(2), N(2), and O(2) collision partners, respectively. The integrated intensities for H(2) and N(2) agree well with previously measured and calculated results, while the value for O(2), which represents the first theoretical determination for this absorption, is approximately four times greater than the only experimental measurement (0.29 x 10(-4) cm(-2) amagat(-2)). Copyright 2001 Academic Press.     

新型GeS_2-Ga_2S_3-KI玻璃性能的研究

用传统熔融淬冷法制备了新型硫卤玻璃(100-x)(80GeS2-20Ga2S3)-xKI(x=0,10,20mol%).利用差热分析、可见/近红外吸收光谱、红外透射光谱等技术对准三元硫卤玻璃体系GeS2-Ga2S3-KI的组成、结构和性能关系进行了研究.分析结果表明:GeS2-Ga2S3-KI三元系统玻璃具有较宽的玻璃形成区;当KI的含量为10mol%时,玻璃热稳定性最好;随着KI的加入,玻璃的红外截止波长无明显变化,皆为12.5μm;然而随着局域电位场的增大,玻璃的短波吸收限向短波方向发生了移动,光学带隙存在增大趋势.     

掺铒重金属氧氟硅铋酸盐玻璃的光谱性质

研究了重金属氧氟硅铋酸盐玻璃 (50-x)SiO2 xBi2O3 50PbF2(x=0, 3, 5, 8, 10, 13, 15 mol%)中Er3+离子的吸收光谱、荧光光谱、荧光半高宽、荧光 寿命和热稳定性能.应用Judd Ofelt理论计算了玻璃的强度参数Ωt(t=2,4,6)，应用 McCumber计算了能级4I13/2→4I15/2跃迁的受激发射截面. 结果发现荧光半高宽与Ω6有较大联系，Ω6越大，荧光半高宽越宽.对Er3+ 关键词： 重金属氧氟硅铋酸盐玻璃 光谱性质 Er3+离子 Judd Ofelt参数     

载银多孔抗菌玻璃的研制

采用Na2O-B2O3-SiO2系统玻璃制备了多孔玻璃,多孔玻璃的气孔率为30%左右,比表面积82-92m2/g,孔径3.4-4.6nm,采用离子导入法制备了多孔抗菌玻璃,研究了在多孔抗菌玻璃的制备过程中,多孔玻璃的孔隙率、溶液的温度、反应时间、溶液的pH值、Ag+的浓度对吸附的影响。制得了Ag+含量在30mg/g以上的多孔抗菌玻璃。经检测所制备的多孔抗菌玻璃对大肠杆菌菌种具有良好的抗菌性能。     

Anomalously large oxygen-ordering contribution to the thermal expansion of untwinned YBa2Cu3O6.95 single crystals: A glasslike transition near room temperature

We present high-resolution thermal expansion data from 5-500 K of untwinned YBa2Cu3Ox (Y123) single crystals for x approximately 6.95 and x = 7.0. Large contributions to the thermal expansivities due to O ordering are found for x approximately 6.95, which disappear below a kinetic glasslike transition near 280 K. The kinetics at this glass transition is governed by an energy barrier of 0.98+/-0.07 eV, in very good agreement with other O-ordering studies. Using thermodynamic arguments, we show that O ordering in the Y123 system is particularly sensitive to uniaxial stress along the chain axis and that the lack of well-ordered chains in Nd123 and La123 is most likely a consequence of a chemical-pressure effect.     

Flexible and rapidly configurable femtosecond pulse generation in the mid-IR

We demonstrate a new experimental approach for flexible femtosecond pulse generation in the mid-IR by use of difference-frequency generation from two tightly synchronized Ti:sapphire lasers. The resultant mid-IR pulse train can be easily tuned, with an adjustable repetition frequency up to 100 MHz, a pulse energy of approximately 1.5 x 10(-13) J, and an intensity noise similar to that of the Ti:sapphire. Rapid switching of the mid-IR wavelength and programmable amplitude modulation are achieved by precision setting of the time delay between two original pulses.     

UV–VIS and mid-IR ellipsometer characterization of layers used in OLED devices

We report on the analysis of layer materials commonly used for the fabrication of organic light-emitting diodes (OLEDs) by means of spectroscopic ellipsometry operating in the ultraviolet–visible (UV–VIS) and in the mid-infrared (mid-IR) range of the electromagnetic spectrum. On covering a wide spectral range, these non-destructive, non-contact techniques offer a huge potential in characterizing thin films in terms of layer thickness values, optical indices, absorption properties modified by incorporating optically active dopant molecules, and, finally, electrical layer properties. Individual absorption bands of single organic films can significantly affect the luminance and performance efficiency of OLEDs when building multi-layer stacks. Using mid-IR spectroscopic ellipsometry, the resistance of as-deposited and annealed indium–tin oxide (ITO) layers on glass is determined and compared with values obtained by four-point probe techniques.