激光威胁源告警定向技术研究

分析了来自战场的激光威胁源,主要有两方面:一是激光战术侦察,一是激光武器和激光制导武器.论述了激光辐射探测原理,其中包括激光辐射截获接收途径、探测原理分类、适于激光辐射探测光学系统的特点及用于激光辐射探测的敏感元件.深入分析了激光威胁源告警定向技术,并对两种适用的告警方案给予详细介绍.     

高精度激光差动共焦超长焦距测量方法与技术研究

<正>超长焦距透镜被广泛应用于激光聚变系统、空间光学系统和高能激光武器等大型光学系统研究领域中,超长焦距测量精度直接影响到大型光学系统的成像质量及使用性能。因此,开展高精度超长焦距的测量方法和技术研究对于大型光学系统具有重要应用价值。论文主要完成了以下工作:开展了一种具有参考镜焦距和组合透镜间隔自校准能力的激光差动共焦组合焦距测量方法研究,利用差动共焦精密定焦     

最亮手持激光器在美问世 亮度为阳光八千倍

从CD到DVD,激光技术的触角已经延伸到地球的每一个角落。科学家研制的激光器中绝大多数能量很小,与科幻作品中可怕的太空激光武器相差十万八千里。在研制激光器的道路上,美国Wicked激光公司又向前迈出一步,他们研制的S3氪激光器射程可达到85英里（约合136公里）,可以穿过房间点燃纸张,能够从地球大气层锁定地面上的物体。S3氪激光的亮度达到阳光的8000倍,是世界上亮度最高的手持激光器。目前,吉尼斯世界纪录组织正对这一激光器进行评估。     

激光喷丸技术及其应用

随着激光技术的发展，高能激光和材料相互作用产生的高幅冲击波技术已得到了广泛研究。激光喷丸技术就是利用强脉冲激光诱导产生的高能冲击波在金属材料表面改性和成形方面的一个应用。介绍了激光喷丸强化和激光喷丸成形的机理、特点和工业应用，并对应用前景作了分析。     

基于PC平台的激光加工数控系统

针对发展新型激光加工装备的需求，分析了激光加工控制的特殊性，研究了激光加工数控系统的体系结构，给出了关键环节的实现技术，在此基础上开发了基于PC平台的激光加工数控系统产品。这种新型数控系统具有可靠性高、性能好、功能强和成本低等显著特点，具有广阔的应用前景。     

呵护刚起步的精益研发

在经济全球化的今天,信息化与工业化融合已经成为当前我国工业化发展的鲜明的主旋律。在这个过程中,该用什么样的战略和战术来促进、支持企业做大做强？     

纳秒激光薄膜损伤机理和应用研究

根据我国强激光装置建设和工程任务对强激光薄膜元件的需求,基于对薄膜损伤机制的认识,同济大学提出了“全流程定量化”控制缺陷制备激光薄膜的思路。同济大学利用结构、性质可控人工小球制作定量化人工缺陷,系统研究了基板加工、超声清洗、电场模拟与调控、镀膜材料与工艺选择、镀后后处理、激光预处理、传递与保存等因素对薄膜元件激光损伤特性和损伤规律的影响。从损伤形貌和损伤规律上证实了节瘤缺陷电场增强理论模型的正确性,促进了研究人员对节瘤缺陷损伤机制的认知深度,提出了提升薄膜损伤性能的新途径,创建了新材料,实现了可兼顾环境稳定性、光谱特性和损伤特性的多功能强激光薄膜制备,有力支撑了我国强激光装置建设和激光技术的进一步提升。     

LNG接收站可燃气检测仪表选型及优化设计

该文介绍了可燃气体探测报警系统组成,并对常用的可燃气检测技术进行了综合比较;介绍了激光可燃气体检测技术的应用优势。实际应用表明,激光吸收光谱技术检测甲烷具有反应速度快、抗其他可燃气干扰能力强、安全性高等特点,对LNG接收站可燃气检测技术发展具有重要推广价值。     

激光冲击处理技术的最新发展

激光冲击处理技术(又称激光喷丸)是利用强脉冲激光产生的压力冲击波在金属材料表层产生应变硬化的一种新型表面强化技术。介绍了激光冲击处理技术的特点，分析了国内外最新发展状况，特别是LLNL，MIC，GE等公司应用激光冲击强化涡轮发动机零件的工艺，最后总结了该技术在改善疲劳性能方面的应用前景。     

CO_2连续激光焊接与切割

激光技术是六十年代发展起来的一项新技术,由于激光束具有单色性强、方向性好和能量密度高等特点,因此在工业、农业、医学、国防和科学研究中已开始得到广泛的应用。激光作为一种新型的热源,自然也被引用于焊接与切割,随着国民经济发展的需要,我所于1971年起开始对100W级CO_2连续激光焊接技术进行探讨,在试验过程中,发扬自力更生精种,自己动手搞成了一套100W级CO_2连续激光焊接设备,在此基础上进行焊接和切割试验。一、试验设备     

两维快速控制水冷反射镜装置设计

通过对高功率激光发射系统中,从激光器到发射系统的强激光通道内光束传输质量的分析,发现了影响光束传输精度的原因。设计了一种新型两维快速控制水冷反射镜装置,解决了强激光传输方向的精确实时控制和校正光束整体倾斜方向的问题,实现了减小镜面热畸变提高光束质量的功能。试验测试结果表明,两维快速控制水冷反射镜装置工作稳定、可靠;具有质量轻、转动惯量小、行程小、谐振频率高、响应速度快、动态滞后误差小等优点。此装置设计合理,具有应用推广价值。     

Apparatus for laser-assisted electron scattering in femtosecond intense laser fields

An apparatus for observation of laser-assisted electron scattering (LAES) in femtosecond intense laser fields was developed. The unique apparatus has three essential components, i.e., a photocathode-type ultrashort pulsed-electron gun, a toroidal-type electron energy analyzer enabling simultaneous detection of energy and angular distributions of scattered electrons with high efficiency, and a high repetition-rate data acquisition system combined with a high power 5 kHz Ti:sapphire laser system. These advantages make extremely weak femtosecond-LAES signals distinguishable from the huge elastic scattering signals. A precise method for securing a spatial overlap between three beams, that is, an atomic beam, an electron beam, and a laser beam, and synchronization between the electron and laser pulses is described. As a demonstration of this apparatus, an electron energy spectrum of the LAES signals with 1.4 × 10(12) W/cm(2), 795 nm, 50 fs laser pulses was observed, and the detection limit and further improvements of the apparatus are examined.     

Analysis and experiment on deformation of sheet metal by laser shock wave

The mechanism of laser shock deformation and the reason for the production of the shockwave are introduced. An evaluation formula of the detonation wave pressure in the system of laser, energy transferring-medium and sheet metal is built according to the theory of detonation wave and blasting gas-dynamics. The minimal energy of the laser pulse is evaluated on the basis of the formula of the laser shock pressure and evaluation of dynamic yielding strength. The experiment is also validated. The result shows that the quantity of sheet metal deforming is nonlinearly increased with laser energy, i.e., pressure of the laser shock wave. Under a laser-induced ultra-high pressure and high strain rate, structural steels and composite materials undergo plastic deformation. __________ Translated from Journal of Nanjing University of Aeronautics and Astronautic, 2005(S1) (in Chinese)     

激光喷丸强化系统协调控制方法与实现

针对复杂型面工件激光喷丸强化应用中对加工点位精度的要求以及激光脉冲触发时间点需要与工业机器人调姿到位时间点精确匹配,提出激光脉冲与工业机器人协调控制方法。通过脉冲能量检测实现出光快速反馈,并基于EKI接口通讯实现KUKA机器人运动控制及到位反馈,完成激光脉冲与工业机器人点位运动闭环匹配。在此基础上研制激光喷丸强化工艺系统,主要包含激光光源、工业机器人、传输光路、工艺辅助模块以及上位机控制平台。以平面点阵坐标进行协调控制实验及对整体叶盘进行激光喷丸强化实验。结果表明,本系统具备较好的激光脉冲-工业机器人协调控制精度,能自动完成激光喷丸强化工艺流程,具有对复杂型面工件的激光喷丸强化能力。     

准分子激光脉冲直写刻蚀速率与能量密度的关系

为了探索低成本、大深宽比加工方法,建立了实用的准分子激光微加工系统.以玻璃为实验靶材,用精密微动平台准确调节靶材位置,利用波长248nm的KrF准分子激光器,研究了准分子激光直写刻蚀过程中平均刻蚀速率与激光脉冲能量密度之间的关系.加工出的沟槽剖面形状均呈现锥型,单脉冲烧蚀速率随脉冲数的增加而减小,激光脉冲对材料的刻蚀具有能量阈值,加工槽的深度具有上限值.采用平行激光束或对加工过程进行动态控制还可实现矩形深槽或圆柱深孔的加工.     

高精度动载体激光发射系统光束控制反射镜

设计了一种适于车载等运动环境下的快速控制反射镜, 用于在具有振动和冲击的工作环境下控制激光发射系统的激光光束稳定及其精确校准。根据某光学系统的性能指标要求,阐述了用于高能激光的平面反射镜的物理性能以及控制反射镜负载应有的机械特性。采用大行程的音圈电机作为控制反射镜的驱动器,并设计了精度高、抗干扰能力强的角位移测量装置作为控制反射镜的位置传感器。对所采用的4个音圈电机和4个角位移测量装置进行了合理布局,既降低了系统的转动惯量又提高了系统的可靠性和环境适应性。实验结果表明：该快速控制反射镜的定位精度优于1.4″,满足高能激光发射系统对控制反射镜的精度要求。     

A TEA CO2 laser with a peak radiation power of 100 MW

A high-power pulse-periodic TEA CO₂ laser is used as a component of a long-range mobile differential absorption lidar. In order to reach the ultimate peak generation power, a system for laser excitation with a supply voltage of ±40 kV and efficient preionization was developed, allowing the laser to operate at high pressures of gas mixtures of various compositions. Energy, time, and spatial characteristics of laser radiation were studied. Laser pulses with an energy of >10 J and FWHM duration of ≈30 ns were obtained. The ultimate peak laser radiation power is 100 MW, and the maximum efficiency with respect to the discharge-consumed energy is 12.6%.     

New methods for high current fast ion beam production by laser-driven acceleration

An overview of the last experimental campaigns on laser-driven ion acceleration performed at the PALS facility in Prague is given. Both the 2 TW, sub-nanosecond iodine laser system and the 20 TW, femtosecond Ti:sapphire laser, recently installed at PALS, are used along our experiments performed in the intensity range 10(16)-10(19) W∕cm(2). The main goal of our studies was to generate high energy, high current ion streams at relatively low laser intensities. The discussed experimental investigations show promising results in terms of maximum ion energy and current density, which make the laser-accelerated ion beams a candidate for new-generation ion sources to be employed in medicine, nuclear physics, matter physics, and industry.     

Neural network modeling and analysis of the material removal process during laser machining

To manufacture parts with nano- or micro-scale geometry using laser machining, it is essential to have a thorough understanding of the material removal process in order to control the system behaviour. At present, the operator must use trial-and-error methods to set the process control parameters related to the laser beam, motion system, and work piece material. In addition, dynamic characteristics of the process that cannot be controlled by the operator such as power density fluctuations, intensity distribution within the laser beam, and thermal effects can significantly influence the machining process and the quality of part geometry. This paper describes how a multi-layered neural network can be used to model the nonlinear laser micro-machining process in an effort to predict the level of pulse energy needed to create a dent or crater with the desired depth and diameter. Laser pulses of different energy levels are impinged on the surface of several test materials in order to investigate the effect of pulse energy on the resulting crater geometry and the volume of material removed. The experimentally acquired data is used to train and test the neural network's performance. The key system inputs for the process model are mean depth and mean diameter of the crater, and the system outputs are pulse energy, variance of depth and variance of diameter. This study demonstrates that the proposed neural network approach can predict the behaviour of the material removal process during laser machining to a high degree of accuracy.