用半导体环形激光器产生混沌信号

提出了一种由一个分布式反馈激光器为主激光器和一个半导体环形激光器为从激光器组成的主从式激光混沌系统方案,主激光器产生的光单向注入到从激光器中,通过调整注入系数、主从激光器的失谐频率和从激光器的偏置电流,使从激光器工作在混沌状态,输出混沌信号。从基于光注入条件下的环形激光器的速率方程组入手,数值模拟了主从激光器的失谐频率、注入系数和从激光器的偏置电流3个工作参量对从激光器输出动态的影响。研究表明:外光注入条件下,半导体环形激光器可以产生混沌信号。通过分析得出:当失谐频率为3.9 GHz、注入系数为0.07、偏置电流为81 mA时,环形激光器可以产生功率谱平坦、带宽较宽的高质量混沌信号。     

高能激光技术进展与面临的挑战

文章分析和比较了几种高能激光器技术发展现状和面临的挑战,以及各自可能适用的范围.特别对二极管抽运固体激光器和光纤激光器的几种束相干合成方法和光束质量评价方法进行了分析和讨论.二极管抽运固体激光器和光纤激光器近十年来异军突起,被人们看作是继化学激光器后的第二代高能激光器.光纤激光器进展要比二极管抽运固体激光器滞后5到10年.对几十万瓦以上的激光器来说,在相当长的时间内仍然要靠化学激光器.     

光纤激光器

分别论述稀土掺杂光纤激光器、单晶光纤激光器、塑料光纤激光器、非线性光纤激光器，并展望了光纤激光器的未来。     

光纤激光宽温度范围运行研究进展

简要回顾了高功率掺镱光纤激光器的发展历程,指出宽温运行光纤激光器的需求与应用场景。综述已有关于光纤激光器在变温条件下的研究成果,在高功率光纤激光器的发展中,工作温度对光纤激光器造成的影响将进一步显现。介绍了利用现有光纤器件以及传统光纤激光器设计的宽温运行光纤激光器案例。通过系统设计和结构优化,本课题组已成功实现千瓦级的宽温运行光纤激光器,整机运行温度从常温拓展到-30℃。进一步的功率提升和温度范围拓展还需要对光纤激光器工作机理、光纤器件温度特性等方面进行深入研究。此外,展望了宽温运行光纤激光器的发展趋势,研究结果为高功率宽温运行光纤激光器的发展提供了参考。     

大功率半导体激光器研究进展

对半导体激光器的发展历史和发展现状进行了综述,并具体介绍了长春光学精密机械与物理研究所近年来在大功率半导体激光器方面所取得的主要进展,特别是在大功率半导体激光器的激光光源、垂直腔面发射激光器和新型激光器芯片等方面。     

高能掺镱离子光纤激光器的研究

从激光器的速率方程出发,对光纤激光器的工作原理以及输出特性进行了研究,得到了光纤激光器在稳态条件下阈值条件和激光器输出功率的表达式.利用数值模拟结果对光纤激光器基本参量进行分析和论证.为光纤激光器的优化设计提供理论依据.并提出了全光纤型光纤激光器的实验方法.获得了最大功率7.5 W、波长1080 nm、峰值半宽0.11 nm的连续单模激光输出.     

线性调频半导体激光器自混频干涉理论模型

使用半导体激光器在弱反馈条件下的动力学理论,建立了线性调频半导体激光器的自混频干涉理论模型.基于该模型,分析了激光器振荡频率偏移与输出功率变化特性.通过测量激光器输出功率谱,可以得到激光器前端面与被测目标之间的距离.     

封面说明

激光器是20世纪最重大的技发明之一,今年是激光器发明50周年.第一台激光器是梅曼(T.Maiman)制成的红宝石激光器,于1960年5月16日开始运转.     

眼睛安全激光器及军事应用

描述眼睛安全激光器的发展近况及军事应用。详细介绍眼睛安全的激光测距机。所述眼睛安全激光器包括CO_2激光器、GaAs半导体二极管激光器、Q开关Er玻璃激光器、Nd:YAG喇曼激光器、中红外激光器和KPT光学参量振荡器。     

大功率全固态激光数控加工机床

工业焊接切割使用的大功率激光器主要经历了CO．激光器、灯泵浦Nd：YAG固体激光器阶段,现在正向全固态激光器的应用方向发展。全固态激光器集半导体激光器和固体激光器的优势于一体,具有体积小、重量轻、效率高、性能稳定、可靠性好、寿命长、光束质量高等优点,近年来已成为激光学科的重点发展方向之一,大功率全固态激光器在工业加工、军事和科研等领域中有着十分重要的应用前景。     

A perfect centrifuge

The theory of separation in a Zippe gas centrifuge based on the radial averaging method has been developed. A more general way of deriving the one-dimensional diffusion equation is proposed. The applicability of the averaging method for an arbitrary distribution of the circulation flow along the centrifuge axis has been demonstrated. The general solution has been obtained, and the optimal internal circulation, that is, a perfect centrifuge, has been defined. The maximum separative power of the perfect centrifuge is expressed as a function of the external parameters.     

A microwave photon detector

The possibility of the implementation of a single-photon detector in the microwave range has been discussed. It has been shown that, for these purposes, it is possible to use an unshunted Josephson junction, which is switched from the superconducting state into a finite-voltage state at the presence of an external signal. The sensitivity of this detector is determined by the distribution of switchings in the absence of an external signal. It has been demonstrated that there is a Josephson junction with a noise temperature below 60 mK at a nominal external temperature of 10 mK. A specific detector intended for the measurement of external microwave signals has been proposed, designed, and fabricated. The first experimental results have been presented.     

一种新型选通象增强高速电影系统

为了实现对“弱、小、多、快”目标的跟踪测量,我们研制了一种选通象增强高速电影摄影系统。它是集激光象增强技术、激光照明技术、电子选通技术及高速电影摄影技术于一体的新型系统,它具有光增益高,成象质量好,可探测距离远等特点。 该系统采用了带选通的二代象增强器;采用了电子快门,其曝光时间在1μs—300μs可调,频率在1—100帧/秒可调;采用了非透镜耦合的方式,解决了胶片与耦合面板之间的静电放电问题,以及高速运转时它们之间的磨擦问题,采用了小数值孔径耦合面板,改善了耦合分辨率,采用了高性能的间歇输片机构,实现了胶片的高速间歇运动。 本文还介绍了该系统的静态和动态测试结果,以及在激光照明下的测试结果。     

漫射光宽视场光学天线的设计

利用光线追迹的方法分析了半球光学天线及另外两种截取角小于90°的欠半球和大于90°的超半球光学天线的光学增益和接收视场,提出了选择合适截取角的原则,并确认半球形光学天线是一种很合适的漫射光宽视场光学天线;同时分析了均匀能量环境下半球光学天线圆截面上接收到光功率的分布,并提出了设计半球形光学天线基本参量的原则;用光学理论推导出了采用半球形光学天线时能够到达光敏面的光线所应满足的条件,分析了它对光学滤波设计的意义.     

A cosmological study in massive gravity theory

A detailed study of the various cosmological aspects in massive gravity theory has been presented in the present work. For the homogeneous and isotropic FLRW model, the deceleration parameter has been evaluated, and, it has been examined whether there is any transition from deceleration to acceleration in recent past, or not. With the proper choice of the free parameters, it has been shown that the massive gravity theory is equivalent to Einstein gravity with a modified Newtonian gravitational constant together with a negative cosmological constant. Also, in this context, it has been examined whether the emergent scenario is possible, or not, in massive gravity theory. Finally, we have done a cosmographic analysis in massive gravity theory.     

A COAXIAL MAGNETRON INJECTION GUN (CMIG) FOR A 2 MW, 170 GHz COAXIAL CAVITY GYROTRON

An electron gun (80 kV / 75 A) for a 170 GHz coaxial cavity gyrotron has been designed, fabricated and tested. Special care has been devoted to the design of the technical part of the electron gun in order to avoid trapping of electrons, which may result in a limitation of the high voltage performance due to built-up of a Penning discharge which may limit the high voltage performance. The performance of the electron gun and electron beam has been found to be well in agreement with the design objective. A stable operation up to I_b = 80 A and U_c = 80 kV has been obtained without any observable beam instabilities. No limitations in high voltage performance due to built-up of a Penning discharge occurred. The influence of the type of electron flow on gyrotron performance has been studied experimentally. The maximum output power has been obtained for an intermediate type of flow.     

双稳液晶电光调制器

本文介绍了一种新的液晶混合双稳光学装置(LCBOD),观察到了液晶BOD两种运用方式的光学双稳态,描述了液晶BOD在光学逻辑元件和超线性调制上的应用,还研究了液晶BOD的瞬态响应,观察到了“临界延迟”现象,测量了开关时间,实验结果与Garmire的理论相符。 关键词：     

等离子体中的颗粒成长模型

研究等离子体环境下的带电微小颗粒的成长过程．在收集离子和颗粒间凝合两种成长机制中,后者起主要作用,使生成的颗粒粒度接近．基于能量均分定理提出一个简化的模型,推导出颗粒粒度分布函数的动力方程．初步的数值模拟结果证实了上述成长机制的设想. 关键词：     

A Personal Journey Through Hadronic Exotica

The search for exotic hadrons has been forever fascinating and challenging. A review of many such searches, successful and unsuccessful, in which the author has been involved, is presented.     

A simple model of triton

A model of triton has been considered in which three interactions between nucleons have been approximated by harmonic oscillator forces of different strengths. The parameters have been determined by fitting the mass radius, the charge radius and the binding energy of the triton. The model involves an exact solution of the threebody problem. The wave function parameters and various physical parameters of the triton have been calculated. The assessment of the neutron-neutron interaction has been obtained irrespectively of the charge independence of nuclear forces. The model provides the possibility of testing the fulfilment of charge independence using the neutron-proton interaction only.