超高速行波电吸收调制器的k值设计方法

介绍了一种用于超高速行波电吸收调制器(TW-EAM)设计的“k值带宽法”.该方法考虑了影响调制器带宽的阻抗失配、相速度失配、微波衰减等因素,说明一个优化设计的TW-EAM其带宽可达到140 GHz.     

一种多用途的光电自动微调器

本文介绍一种多用途光电自动微调器,它是由单片微机控制的具有自动反馈功能的光电子器件,适用于各种利用微调方式对光路进行实时自动反馈式平衡准直和精密测量.     

GaN薄膜的蓝光和红光发射机理研究

由于生长工艺的不完善，非掺杂GaN薄膜中通常存在未知的杂质和缺陷，产生与这些未知杂质和缺陷能级相关的发光。报道了非掺杂GaN薄膜的692nm红色发光．并研究了非掺杂GaN薄膜的蓝、红色发光的发射机理；利用作者提出的吸收归一化光致发光激发光谱，直接测量出了非掺杂GaN薄膜的蓝、红色发光的初始态能级，确定蓝色发光为施主-价带跃迁复合，而红色发光为施主-受主跃迁复合；给出了黄、蓝、红光的发射模型。所取得的结果对于确定未知杂质和缺陷的种类具有重要的参考价值。     

EFFECTS OF BANDGAP SHRINKAGE IN FEMTOSECOND ABSORPTION SATURATION MEASUREMENTS OF GaAs FILM

Using CPM dye laser and self-mode-locked Ti sapphire laser as pump-probe optical sources, the effects of bandfilling and bandgap shrinkage on the femtosecond absorption saturation spectra of GaAs film have been studied, For exciting photon energy of 1.97eV and carrier density of 1×10¹⁸cm^-3, an optical-induced absorption increase is observed and is attributed to bandgap shrinkage, The dependence of the absorption coefficient change on the carrier temperature and the carrier densities is discussed.     

RELAXATION DYNAMICS OF PHOTOINDUCED EXCITON BLEACHING IN POLYMERS

Presented in this paper are systematic studies of photoiuduced exciton bleaching dynamics in the polymers with nondegenerate ground state, such as polydiacetylene, polythiophene and polyaniline. From a three-level model, the photoexcitation and relaxation of the exciton bleaching in the polymers are simulated. The results show that the exciton bleaching decay is composed of two components, the fast component and the slow component. For the fast component, the speed of exciton bleaching decay depends on the way in which the excitons relax. When the relaxation of the exciton to the ground state is dominant, the polymers exhibit an ultrafast initial bleaching relaxation; when the relaxation of the exciton to the self-trapped exciton state is dominant, the polymers exhibit a slower initial bleaching relaxation than that in the former case, For the slow component, the exciton bleaching decay is due to the relaxation of the self-trapped excitons to the ground state. Using femtosecond time-resolved pump-probe technology, we measured the relaxation dynamics of the photoinduced exciton bleaching in the emeraldine base form of polyaniline. Fitting the experimental data to the theoretical model indicates that the fast component arises from the relaxation of excitons to the ground state (～100fs) and the slow component arises from the relaxation of self-trapped excitons to the ground state (～30 ps).     

8-羟基喹啉铝高分子复合物薄膜的瞬态荧光特性与机理

对 8 -羟基喹啉铝 (Alq3)高分子复合物薄膜的的瞬态荧光特性和机理进行了研究 ,发现复合物薄膜的荧光寿命比 Alq3样品的寿命明显缩短 ,荧光峰值波长紫移 ,高分子基质引起的淬灭过程可能是导致复合物薄膜寿命降低的主要原因 ,而 Alq3分子与基质分子间的互作用则引起荧光峰值波长的移动。     

GaAs中电子g因子的温度和能量依赖性的飞秒激光吸收量子拍研究

采用时间分辨椭圆偏振光抽运-探测光谱研究磁场作用下本征GaAs中电子自旋弛豫动力学，观察到吸收量子拍现象.这种吸收量子拍起源于电子自旋的拉莫尔进动，因而其拍频成为高精度测量电子g因子的一种新方法.利用这种新方法研究了本征GaAs中电子g因子的温度和能量依赖特性，发现g因子随电子的温度和能量增加而增加，但与k·p理论预测相差甚大.基于实验结果拟合，我们给出了一个g因子的温度和能量依赖的经验公式. 关键词： 椭圆偏振光抽运-探测光谱 自旋量子拍 g因子 GaAs     

无干涉条纹的光谱位相相干直接电场重构法

提出一种新的诊断飞秒脉冲振幅与位相的高精度测量方法.该方法发展了传统的SPIDER方法，保留了原方法对脉冲信息可以实时、有效和全面地测取的优点，并能克服其不能测量脉宽较大或位相信息复杂的脉冲的缺点.在新方法中和频后的脉冲对没有相对延时，形成无干涉条纹的剪切干涉图.在调节一个小量延时于某些特定值，可去掉剪切干涉图的歧义性.给出数值模拟结果，证明此方法无需经过傅里叶变换滤波，可直接由干涉图唯一地提取出脉冲的振幅与位相信息. 关键词： 光谱位相相干直接电场重构法 飞秒脉冲测量 超快信息光学     

飞秒激光与超快现象(Ⅰ)

文章第Ⅰ部分介绍飞秒激光的发展过程和应用概况，讨论了飞秒脉冲产生和测量的基本原理，以及近年来在物理和技术上的新进展．特别介绍了在飞秒激光器全固体化、小型化、高效化方面的进步．有关飞秒激光技术在超快现象研究中的应用将在第Ⅱ部分介绍．