Luminescence and lasing properties of neodymium- and uranium-activated inorganic laser liquids

An attempt was made to describe and show the possibilities of new inorganic neodynium- and uranium-activated laser liquids: SO₂-GaCl₃-NdCl₄; SO₂Cl₂-GaCl₃-NdCl₃-UO₂Cl₂; POCl₂-MCl_n-NdCl₃-UO₂Cl₂ for development and synthesis of direct nuclear reaction-excited lasers. Luminescence data presented in the work were used to calculate the luminescence parameters of the laser liquids such as oscillator strengths f, probability of spontaneous radiation A, intermultiplet luminescence branching coefficient β, cross-section for induced radiation σ, luminescence decay time τ, quantum yield η, and others. It is shown that the oscillator strengths of the normal absorption bands of Na³⁺, which play the main part in the pumping processes, exceed the oscillator strengths of Na³⁺ for aqueous and many other nonaqueous systems. In the luminescence excitation spectra of the Na³⁺ ion, bands are isolated in the range 400–1000 nm atλ _rec =1.06 μm. With excitation, luminescence occurs through the⁴F_3/2→⁴I_{9/2,11/2.13/2} channels. Luminescence spectral data are related to the lasing parameters. The threshold lasing energy is∼18 J/cm³. For a resonator with mirros h₁=100% and h₂=20, 40, 56, and 80%, the lasing energy is∼20–120 MJ/cm³ in the pumping energy range 18–180 J/cm³. The differential efficiency is ∼0.2% The substantial angular radiation divergence (θ∼4·10⁻² rad) and strong thermostatic distortions that occur in the active element (dn/dT≈−1.9·10⁻⁴K⁻¹) are a disadvantage of laser liquids. It is shown that operation of neodymium- and uranium-activated inorganic liquid lasers is stable under the present conditions. A. I. Gertsen Russian State Pedagogical University, Moika Embankment, 48, St. Petersburg, 191186, Russia. Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 64, No. 5, pp. 607–619, September–October, 1997.     

Zn0.8Cd0.2Se-ZnSe应变层超晶格的激子发光和受激发射

本文用MOCVD技术在GaAs衬底上成功地制备了具有波导结构的Zn0.8Cd0.2Se-ZnSe应变层超晶格样品,在77K温度的光致发光光谱中观测到n=1的重空穴和轻空穴激子的辐射复合。在光泵浦下,在波导结构的F-P腔中观测到具有多模结构的受激发射,受激发射谱中的不同模具有不同的阈值功率密度;时间延迟衰减曲线的半宽度越窄,阈值光强越大.     

二氧化锆纳米材料中Eu3+的发光特性

研究了掺1mol%Eu³⁺的二氧化锆纳米材料随退火温度变化的发光性质，得到退火温度为600和800℃的样品中Eu³⁺的⁵D₀→⁷F₂发射在604nm处，这种现象不多见. 几种经不同退火温度处理的纳米材料样品在紫外光的照射下，稀土离子Eu³⁺的⁵D₀→⁷F₂发射的发光逐 关键词： 二氧化锆 纳米材料 3+')" href="#">Eu³⁺ 发光     

CaAl3BO7：RE(RE=Ce,Gd,Tb)中稀土离子的光谱特性

采用固相反应法合成了CaAl₃BO₇RE(RE=Ce,Gd,Tb),研究了Ce³⁺,Gd³⁺和Tb³⁺的光谱特性。发现铈离子周围存在较强的晶场,使基态的4f能级劈裂较大,从而导致铈离子的特征发射峰重叠较大;Ce³⁺的5d能级明显低于Gd³⁺的⁶I、⁶P能级;Ce³⁺和Tb³⁺之间存在有效的能量传递。     

Mixed iridium(III) and ruthenium(II) polypyridyl complexes containing poly(ε‐caprolactone)‐bipyridine macroligands

A hydroxy‐functionalized bipyridine ligand was polymerized with ε‐caprolactone utilizing the controlled ring‐opening polymerization of ε‐caprolactone in the presence of stannous octoate. The resulting poly(ε‐caprolactone)‐containing bipyridine was characterized by ¹H NMR and IR spectroscopy, and gel permeation chromatography, as well as matrix‐assisted laser desorption/ionization time‐of‐flight mass spectrometry, revealing the successful incorporation of the bipyridine ligand into the polymer chain. Coordination to iridium(III) and ruthenium(II) precursor complexes yielded two macroligand complexes, which were characterized by NMR, gel permeation chromatography, matrix‐assisted laser desorption/ionization time‐of‐flight MS, cyclic voltammetry, and differential scanning calorimetry. In addition, both photophysical and electrochemical properties of the metal‐containing polymers proved the formation of a trisruthenium(II) and a trisiridium(III) polypyridyl species, respectively. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 4153–4160, 2004     

阴极射线激发下ZnO薄膜室温紫外发光的超线性增长规律

研究了直接溅射ＺｎＯ薄膜在阴极射线激发下紫外光（约３９０ｎｍ）和绿光（约５２０ｎｍ）的发光与激发电子束电流密度的关系。随激发电流密度增加绿光相对下降，紫外光相对增强，使得ＺｎＯ薄膜的发光颜色从绿变蓝紫，ＺｎＯ薄膜绿光随电子束流密度的增长呈亚线性增长，并在不高的束流密度下达到饱和，而紫外发光随电子束流密度呈超线性增长，这是ＺｎＯ薄膜在室温阴极射线激发下紫外受激发光的迹象，是高密度激发下的一种超辐射受     

Absorption Spectra of Metal Atoms Adsorbed on the Surface of a Single Crystal

A method for obtaining the spectra of atoms adsorbed on a single crystal with an ion-covalent bond is suggested. A photostimulated burst of luminescence is used to record the spectra. The atoms are deposited in a vacuum by a mass-spectrometric technique. The absorption spectrum of silver atoms adsorbed on a silver chloride single crystal at concentrations comprising a millionth fraction of the surface monolayer has been obtained. It has been revealed that the optical ionization potential of an adsorbed silver atom is equal to 1.9 eV.     

Polarization of the Fluorescence Excited in the P- and R Branches of the Vibronic Lines of Jet-Cooled Complex Molecules

A model is suggested to calculate the degree of polarization of the fluorescence of jet-cooled polyatomic molecules excited within the P- and R branches of the rotational contour of the vibronic line by light not providing resolution of the rotational structure. These dependences are calculated and compared with experimental data for molecules belonging to different types of asymmetric tops with different intramolecular orientation of the fluorescence transition dipole moment: anthracene; anthracene + Ar; 1,4-diaminoanthraquinone; indole; tetracene, and triphendioxazine.     

以蓝色发光材料DPVBi为基质的白色发光器件

白色有机发光器件是实现彩色平板显示的重要方案之一。利用蓝色发光材料DPVBi[4，4′—(2，2—苯乙烯基)—1，1′—联苯]掺杂红光染料DCJTB[4—氰甲烯基—2—叔丁基—6—(1，1，7，7—四甲基久洛尼定基—9—烯炔基—4H—吡喃)]作发光层制备了白色发光器件。研究了DPVBi掺杂不同浓度IDCJTB薄膜的光致发光性质，根据光致发光结果，制备了以DPVBi掺杂不同浓度DCJTB作发光层的电致发光器件，其结构为ITO／GuPc／NPB／DPVBi：DCJTB／Alq3／LiF／Al。当DCJTB质量分数为0．0008时，器件实现了白色发光(色度x=0．25，y=0．32)，电致发光和光致发光的掺杂比例基本相符，表明器件的白色发光主要是由基质DPVBi向掺杂剂DCJTB的能量传递产生的。研究还发现：白色器件随电压升高，光谱中蓝色成分相对于红色成分的比例略有增加，文章对此现象进行了分析。该白光器件在14V时达到最高亮度7822cd／cm^2，在20mA／cm^2电流密度下的亮度为-489cd／cm^2，最大流明效率为1．75lm／W。