溶剂对激光染料DCM的荧光衰变过程的影响

采用时间相关单光子计数技术测量了激光染料DCM在17种质子化和非质子化溶剂中的荧光衰变时间常数。所观察到的溶剂效应可被认为主要是由于激发态分子构型改变和氢键络合物生成所引起。并据此预言:选用高极性、但不能参与生成氢键的非质子化溶剂,是改善DCM染料激光体系输出特性的有效措施之一。     

碘分子高激发态光谱研究

卤素分子的高激发态光谱与结构的研究一直是原子、分子物理及光谱学研究的重要课题．碘分子的高位激发态，尤其是与厂（旬十I＋（’P，‘D仅离子组合相关的三组离子对态，多年来一直是激光光谱研究的重要对象之一。其中较低的几个高于对态已经被仔细研究和标识，而对于高位离子对态，由于态与态之间的相互作用较为复杂，其特性了解得并不完善，尚需做大量的研究工作。研究表明，碘分子各高于对态校间距（典型值几一0．36n叫较基态（R。。0．26urn）大得多，单步激发受到lhanckCondon因于限制，一般很难实现。而采用光学一光学双共振多光子…     

激发态酯类取代基季铵盐水溶铜卟啉与DNA相互作用的共振拉曼研究

本文采用４００ｎｍ和４４５ｎｍ脉冲激光激发测量了４－Ｎ－乙酸乙酯基──吡啶基铜卟啉和镍卟啉［简称Ｃｕ（ＮＥＡＥ）和Ｎｉ（ＮＥＡＥ）］及它们与ＤＺＡ复合物的共振拉曼光谱。分析表明，Ｃｕ（ＮＥＡＥ）与ＤＮＡ形成了电子激发态复合物而Ｎｉ（ＮＥＡＥ）则不能；激发态卟啉π电子与ＤＮＡ碱基π电子间的相互作用比基态时强得多，使卟啉骨架出现了明显畸变，而卟啉的吡啶取代基团变化较小。     

富勒烯-高分子共聚物和富勒烯-金属络合物的飞秒非线性光学研究

富勒烯分子由于其离域的三维。电子结构而表现出较高的三阶非线性系数（对于ｑ。：Ｘ（’）～１０－“ＸＳＳ）．Ｌａｓｃｏｌａ报道Ｃ而离子的三阶非线性极化率比中性Ｃ。。分子高６５倍左右．将Ｃ。。分子与其他非线性材料（如高分子材料）组合使其形成电荷转移材料,从而可望提高材料的非线性极化率．在富勒烯／高分子体系中,由于富勒烯分子和有机聚合物的电子亲和势的差异而使富勒烯分子较容易作为体系的电子受体,而有机聚合物为电子的给体．而在富勒烯／高分子体共聚物体系中,同时存在基态电荷转移和激发态电荷转移过程．电荷转移过…     

266nm激光下硝基苯的多光子电离解离研究

在266nm波长激光下,通过激光质谱仪获得气相硝基苯的共振增强多光子电离/飞行时间质谱（REMPI-TOFMS）。根据质谱图中出现的主要离子峰信息,对硝基苯的光解离过程进行了分析。硝基苯与266nm激光的作用过程为三光子过程,其首先吸收两个光子跃迁至激发态,一部分处于激发态的分子,因内转换导致结构重排,生成分子异构体。处于激发态的硝基苯分子或分子异构体共振吸收一光子后发生解离,并给出其可能的解离通道。     

激光染料的时间分辨光谱研究——香豆素系列荧光衰变过程的溶剂效应

采用时间分辨光谱技术(时间分辨率为0.15ns)系统地研究了两种典型香豆素激光染料(C311和 C102)的荧光衰变过程的溶剂效应。测量结果表明,这类香豆素激光染料的荧光寿命溶剂效应具有“反常”特性,即随着溶剂极性的增大其荧光寿命加大。基于香豆素激光染料处于激发态时发生电荷转移而使分子偶极矩有很大增加这一事实,作者认为处于激发态的染料分子将使溶剂分子进行重新排列,即发生了溶剂“结构化”过程,极性越大,“结构化”程度越高。这种“结构化”效应将阻止染料分子弛豫到基态,从而加大了荧光寿命。但对具有可能转动端基(CH_3)_2N—     

用吸收光谱和共振拉曼光谱研究水溶卟啉Cu（NACN）与DNA相互作用

本文用紫外一可见光谱和共振拉曼交谱发水溶金属卟啉４－Ｎ－乙腈基一吡啶基铜卟啉与ＤＮＡ的相互作用。分析表明，Ｃｕ（ＮＡＣＮ）以光沟槽方式与ＤＷＡ作用；与ＤＮＡ作用后，Ｃｕ（ＮＡＣＮ）的吡啶基团向垂直于卟啉环平面方向转过一个小的角度；在４４５ｎｍ的脉冲激光激发下，Ｃｕ（ＮＡＣＮ）与ＤＮＡ形成激发态复合物，而且Ｃｕ（ＮＡＣＮ）的激发态分子比基态分子现ＤＮＡ作用强。     

MOCVD生长GaAs／AlxGa1—xAs多量子阱子带间红外吸收特性

对ＭＯＣＶＤ生长的ＧａＡｓ（４０Ａ）／ＡｌｘＧａ１－ｘＡｓ（３００Ａ）多量子阱结构观察到阱内电子从基态到第一激态跃迁引起的红外吸收。用Ｂｒｕｋｅｒ红外光谱仪测量，发现了一个峰值在９８６ｃｍ＾－１（１０．１μｍ）带宽为２３７ｃｍ＾－１（９～１１．５μｍ）的强吸收峰，该峰位置与阱内电子从基态到第一激发态跃迁所计算的吸收峰位置基本一致。     

含硫芴基的三苯胺多枝衍生物的光限幅特性

强双光子吸收有机分子在激光光限幅领域具有重要应用价值。通过测量纳秒脉冲下输入/输出光强的变化、纳秒/飞秒抽运下分子的双光子吸收以及单光子荧光衰减曲线,研究了一系列含硫芴基的三苯胺衍生物对纳秒激光的限幅特性与机制。结果表明,分子激发态寿命与激光脉宽在同一量级有助于激发态再吸收;具有长激发态寿命的多枝形分子其激发态再吸收更明显、表观双光子吸收截面显著增大,有利于提高分子的激光限幅效率。     

肉桂醛衍生物的分子二阶非线性光学效应的理论研究

采用ＣＮＤＯ／Ｓ—ＣＩ方法结合引入外场的微扰理论．计算了一系列内桂醛衍生物的分子二阶极化率，并且从微观上探讨了该类化合物取代基的电子性质、取代基位置及其取代数目对分子二阶非线性光学系数的影响。结果表明，该类化合物有较高的分子二阶极化率；取代基的电子性质和取代方式对其有明显的影响。     

Effect of quenching of molecular triplet states in organic dye lasers

The effect of quenching of metastable triplet states upon the efficiency of organic dye lasers is considered in detail by solving the coupled differential equations describing the laser process. It is shown that specific quenching agents for excited triplet states can 1) cause a dramatic increase in the laser efficiency, 2) negate the previous requirements of very fast pumping sources, and 3) permit the use of dyes with relatively small fluorescence quantum yields. The addition of quenching agents that quench both singlet and triplet states (such as molecular oxygen) generally improves the efficiency although not as dramatically. Steady-state solutions were developed that lead to analytical expressions for the laser efficiency and the concentrations of the excited states as a function of time.     

电致磷光及其有机El的量子效率提高

一般有机电致发光（ＯＥＬ）器件仅利用了单重态发射,因而效率较低,为了提高有机ＥＬ效率,人们设法利用三重态的发射提高其量子效率。本文评述了如何利用三重态发射产生的电致磷光提高有机ＥＬ效率问题。     

On One More Property of the Ideal Array Element Pattern

An infinite planar array of controlled elements in the form of overlapped subarrays excited through a multiport circuit is considered. It is analytically shown that the contour element (subarray) pattern with an ideal contour shape corresponding to the absence of backward mutual coupling and, as a consequence, to the 100% element efficiency can be exactly formed at a definite amplitude distribution over the densely arranged small ideal subarray radiators in spite of the fact that each such a radiator in the subarray has low efficiency caused by the presence of backward mutual coupling. If the small ideal radiators are controlled directly (without the multiport circuit), the contour pattern can be formed with 100% array efficiency for any shape of the contour. If the radiators are not ideal, then the efficiency of the array shaping the contour pattern is determined by averaging the mismatch efficiency of the uniformly excited array scanning over the region bounded by the contour pattern.     

Theoretical and experimental investigation of amplified spontaneous emission in electron-beam-pumped semiconductor lasers

Linear and nonlinear theories of amplified spontaneous emission in longitudinally-pumped semiconductor lasers have been developed. Spatial inhomogeneity in three dimensions and spectral inhomogeneity of gain and spontaneous emission are taken into account. Experiments to investigate the dependency of lasing threshold and differential efficiency of electron-beam-pumped semiconductor lasers on excited region diameter have been performed. The results of threshold measurements have agreed well with the linear theory calculations, while accounting for the results of differential efficiency measurements has required the development of a nonlinear theory. The data for non-linear calculations were provided by experiments on saturation of spontaneous emission. The results of experiments have definitely proved the inhomogeneity of gain. Based on the data obtained from experiments, the nonlinear calculations have explained the dependence of differential efficiency on the excited region diameter.     

半电极压电纤维能量收集动力学建模与仿真

半电极含金属芯压电纤维能将环境振动通过弯曲变形转换成电能。运用分析力学方法建立了半电极含金属芯压电纤维能量收集装置的理论模型,推导了在谐波激励下,经过AC-DC转换后的归一化能量表达形式,分析了能量收集效率受金属芯与压电层的半径比、柔度系数比、压电材料的机电耦合系数及外界激励方向的影响,分析结果表明,当半径比达到2.4,材料机电耦合系数达到0.4,能量收集效率会接近相对最大值。本研究结果适用于压电纤维能量收集装置的分析与优化设计。     

GaAs激光器激发带球面透镜圆柱套层光波导纤维的理论分析与计算

本文分析和计算了GaAs激光器对带球面透镜圆柱套层光波导纤维的模式激发效率,给出了获取最佳耦合的参数,得到基模的激发效率可高达90％以上。     

SAW陀螺新型接收电极

该文在理论上分析了声表面波(SAW)陀螺中两列相向传播SAW形成的驻波在哥氏力作用下的相位分布及传播规律,设计出一种新型的接收电极.此电极能将陀螺效应激发的表面波同种电荷积累到一起,改进了原有电极中同根电极上正负相互抵消的缺点,增强了由陀螺效应激发出SAW的接收效率,本结果可对SAW陀螺的设计提供相关参考.     

无声放电辅助激励CO2激光器的研究

用具有扁平放电截面的等离子体管设计一种新颖的 CO2 激光器 ,并用纵向辉光放电和横向无声放电同时激励。阐述了这种激光器的设计原理 ,理论上讨论了激光管内电子浓度的横向分布 ,实验研究了它的工作特性 ,并与仅用辉光放电激励的情况进行比较。实验表明 ,由于横向无声放电的作用使这种激光器的激光功率、工作气压和工作气体中氮的比例有明显的提高 ,激光效率也有所提高 ,而且放电电流能兼顾最大激光输出功率和最佳效率。     

Excitation of the PE20 and PM11 modes in a dielectric-loaded trough waveguide by a dielectric-loaded rectangular waveguide

Theoretical results are obtained for the launching efficiency of the dominant PE20 and PM11 dielectric-loaded trough-waveguide modes excited by a dielectric-loaded rectangular waveguide.     

Off-axis launching into a fibre-optical waveguide

The launching efficiency is calculated for the HE11 mode in an optical-fibre waveguide excited by an off-axis Gaussian laser beam. The dependence of the launching efficiency on small displacements of the fibre is discussed, and possible methods of easing the problem of positional alignment are suggested. Some recent experimental work is described.