Trends in microdisk laser research and linear optical modelling

Research into microdisk lasers demonstrates new achievements both in the technology and in the associated physical effects and applications. Melting and rounding of the disk edge boosts the Q-factors due to improved surface smoothness. In-plane cavity shape is widely used as a design instrument. Optimal shaping of pumped area lowers the threshold power. Photonic molecules made of several microdisks as “photonic atoms” show lasing at several closely spaced frequencies. A microdisk with a single quantum dot as an active region is considered as the most promising system for realisation of a single photon emitter necessary for quantum computing. These new effects and devices can be simulated with accurate numerical techniques, developed recently for “warm-cavity” linear modelling, that are able to bring a new vision of the physics of lasing.     

光/电激发方式对AlGaInP及GaN基LED电学特性的影响

采用光激励与电激励的方式对AlGaInP与InGaN/GaN基LED的电学特性进行了表征,并重点比较分析了两种激励方式的下理想因子这一重要参数的差异.探讨了影响LED理想因子的因素,确定理想因子的适宜注入强度范围.研究结果表明:结温与注入强度是影响LED理想因子的重要因素;对于特定类型的发光二极管,空间电荷区起主导作用...     

微型光学偶极阱中单原子相干操控Rabi振荡的实现及其应用

文章综述了Rabi振荡的基本原理以及微型光学偶极阱中单原子相干操控Rabi振荡的研究进展,同时介绍了其在单光子源、量子寄存器、量子计算等方面的应用,并简要介绍了作者所在小组在微型光学偶极阱中单原子操控方面的实验进展.     

基于GaSe和GaSe_(0.7)S_(0.3)单晶的单脉冲CO_2激光倍频器(英文)

描述了使用电感储能发生器和半导体转换开关泵浦的工作波长为10.6μm的高效CO2激光器。给出了激光泵浦的非线性晶体GaSe和GaSe0.7S0.3的二次谐波振荡的实验数据和理论估算结果。结果显示,GaSe晶体在输入能量为180mJ时,最大能量转换效率为0.38%,倍频激光的峰值功率为8 kW。     

Metrological orientation-confirmation of Si(h h k) using scanning tunneling microscopy

For the periodicity-modulation of the Si(h h k) template between (0 0 1) and (1 1 1), it is necessary to prepare the surface with any orientation within this range, most especially for fabricating useful one-dimensional nanostructures. Especially, when there are no strong X-ray signals using the standard Cu K-α source in the vicinity of any arbitrarily chosen (H H K), it turns out that the line-profile analysis on the topographic image of scanning tunneling microscopy can be a unique way for confirming the orientation of the prepared surface. Though there are a number of small-width facets on the reconstructed surface, if any of well-defined facets, such as (1 1 1), (3 3 7), (1 1 2), and (3 3 5), are included in these facets it is possible to determine the orientation using the weighted-average method.     

远场超分辨随机光重建显微镜(STORM)研究进展

了解细胞内分子尺度的动态和结构的特征是生命科学迫切需要解决的问题,要求远场光学成像要求纳米或亚纳米量级的空间分辨率.介绍了一种实现打破衍射极限的远场荧光显微成像技术--随机光重建显微术(STORM),其分辨率可以达到横向分辨率20 nm,轴向分辨率50 nm,理论上这种方法的空间分辨率可以达到单分子定位的精度.具体介绍...     

Thermally Conducting Partially Ionized Plasma in a Variable Magnetic Field

An infinitely extending homogenous partially ionized plasma endowed with several physical mechanisms and permeated by a variable magnetic field is considered. The combined effect of these parameters, namely, Hall currents, finite conductivity, ion viscosity, collision with neutrals and thermal conductivity on the gravitational instability of the plasma is studied. It is found that the several mechanisms play different physical roles in the perturbed problem. Jeans' Criterion is analyzed in the framework of Tsallis' statistics for possible modifications due to the presence of nonextensive effects. A simple generalization of the Jeans' criterion is obtained and the standard values are obtained in the limiting case q = 1, q being the nonextensive parameter. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)