高能激光武器的发展及卫星激光防护膜的研究

现代战争中激光武器具有举足轻重的作用，激光武器对卫星实施的致盲攻击使抗激光损伤膜的研究成为关键。介绍了高能激光武器的种类及卫星防护膜的研究现状，总结了几种防护措施的优缺点，指出了卫星防护膜的发展趋势。     

激光对卫星的威胁及其防护

激光技术的广泛应用,由此带来的激光损伤和激光威胁日益严重.在现代高技术战争中,卫星的作用越来越重要,而激光反卫星武器的出现和发展,使卫星也面临着激光的威胁,因此,对卫星的激光防护材料和防护措施的研究具有重要的意义.介绍了激光反卫星武器的分类、性能、作用方式和关键技术;探讨了激光武器对星载光电传感器和材料的杀伤机理;总结了目前基于线性光学原理、非线性光学原理和相变光学原理的激光防护材料的性能、优缺点和改进措施,其中详细介绍了比较有发展潜力的富勒烯、卟啉和VO2薄膜激光防护材料;介绍了几种卫星结构材料的激光防护措施.这有助于对卫星的激光防护的重要性和技术手段的进一步认识.     

高质量CVD金刚石自支撑膜的连续激光损伤研究

利用HJ - 4型连续CO2 激光对金刚石膜进行了激光损伤阈值的研究,损伤后的金刚石膜用SEM和Raman进行了表征。研究结果表明,高质量CVD自支撑金刚石膜具有较高的 激光损伤阈值,金刚石膜抗连续激光损伤阈值的范围是在1. 15 ×106 ～2. 26 ×106W / cm2。金刚石膜激光损伤主要是由于热震损伤,其机制属于热- 力耦合机制。     

星载光学遥感仪器激光防护薄膜技术

激光武器的迅速发展使得激光防护技术研究成为必要，目前，破坏卫星上的遥感仪器是激光反卫星的一个主要可能途径。为了有效防护星载遥感仪器，利用光学薄膜方法，可以对氧碘激光进行防护的薄膜，在不影响遥感仪器正常工作的条件下，可将遥感仪器的激光损伤或致盲阈值提高80倍，大幅度提高了遥感仪器的生存能力。     

HfO2/SiO2多层高反膜脉冲YAG激光预处理机理的研究

本文研究了HfO2 /SiO2 多层高反膜脉冲YAG激光预处理提高抗激光损伤阈值的机理。通过分析和计算 ,我们提出了一种物理模型 ,即热扩散模型。由于扩散结果 ,导致HfO2 膜层的折射率增加 ,致使HfO2 、SiO2 膜层交界处光驻波波峰降低 ,从而提高了薄膜抗激光损伤阈值     

K9玻璃表面的1064nm激光损伤

K9玻璃是一种性能优异的光学材料，作为激光薄膜的基底，其抗激光损伤的特性和能力，直接影响高功率激光薄膜的性能，特别是对激光增透，偏振膜。本论文采用10ns的1064m激光，实验研究了K9玻璃前后的激光损伤特性，用Normski显微镜分析损伤图貌，结果显示玻璃前后表面的激光损伤表现不同。前表面主要表现为烧伤，后表面主要表现为破斑，前后表面的损伤阈值之比约为1．4。后表面的损伤形貌与前表面相比，基本为灾难性损伤，多次激光脉冲打击显示，后表面的激光损伤尺度随着激光脉冲数呈指数增长。     

高损伤阈值激光反射镜的设计方法

为了提高激光反射膜的光谱特性和抗激光损伤特性,提出了一种高损伤阈值激光反射镜的设计方法：采用HfO2-Nb2O5-SiO2多材料混合膜系结构,利用Nb2O5-SiO2折射率差值大的特点,在较少的膜层数下达到高反射率要求;利用HfO2-SiO2组合具有高的抗激光损伤特点,在Nb2O5-SiO2膜堆的最外部分叠加HfO2-SiO2膜堆,取长补短,做到采用较少的膜层数,达到高反射率要求,同时提高薄膜的抗激光损伤能力.该方法能灵活有效地按照不同膜系要求进行材料组合,具有很高的实用价值,达到工程最优化设计.     

1.06μm激光对光学薄膜的损伤

本文讨论光学薄膜的激光损伤类型及原因,探讨底板表面光洁度的影响,就减反膜和反射膜的激光损伤加以研究,提出几种提高抗激光能力的方法。     

全息激光防护薄膜的防护效果试验

研制成功了全息激光防护薄膜。本文报道了全息激光防护薄膜对强功率激光的防护效果试验。试验表明:薄膜对0.53μm波长激光的平均光密度D为4.11,有效防护角为15°,抗激光破坏能力强;在60mJ激光入射能量内,薄膜对兔眼的激光防护效果显着,眼损伤的发生率为百分之零。     

HfO2／SiO2光学薄膜激光损伤阈值的测量

参照国际标准ISO11254及其规范，组建了小口径1064nm激光的损伤阈值测量装置，能对各种光学元件，包括高反膜、偏振膜及增透膜等进行了1064nm激光损伤阈值测量，按损伤阈值测量国际标准的要求，测量了由HfO2/SiO2镀制的1064nm高反膜，偏振膜及增透膜的激光损伤阈值，分析了它们的激光损伤特性，对于10ns的1064nm激光脉冲，高反膜的损伤阈值为12.8J/cm^2，偏振膜为9.8J/cm^2，增透膜为9.2J/cm^2，对于20ns，1ns的激光脉冲，高反膜的损伤阈值分别为15.3J/cm^2和5.75J/cm^2，高反膜的损伤阈值对于ns激光脉冲符合时间定标率τ^0.35。     

Functional Perovskites – From Epitaxial Films to Nanostructured Arrays

Functional perovskite materials gain increasing significance due to their wide spectrum of attractive properties, including ferroelectric, ferromagnetic, conducting and multiferroic properties. Due to the developments of recent years, materials of this type can conveniently be grown, mainly by pulsed laser deposition, in the form of epitaxial films, multilayers, superlattices, and well‐ordered arrays of nanoislands. These structures allow for investigations of preparation–microstructure–property relations. A wide variation of the properties is possible, determined by strain, composition, defect contents, dimensional effects, and crystallographic orientation. An overview of our corresponding work of recent years is given, particularly focusing on epitaxial films, superlattices and nanoisland arrays of (anti)ferroelectric and multiferroic functional perovskites.     

光谱选择性激光隐身材料研究现状

综述了稀土上转换、光子晶体和有机体系光谱选择性激光隐身材料的光谱选择吸收机理,稀土上转换材料通过上转换原理、光子晶体材料通过膜系材料结构设计、有机体系材料通过特定官能团振动均可实现特定波段光谱能量的选择性吸收。分析了三种光谱选择吸收材料应用于激光隐身的可行性和激光隐身的实现方式,综述了材料的研究现状。指出,光谱选择性激...     

二氧化钒薄膜在激光防护上的应用研究

战场上激光武器的不断发展对激光防护提出了更高的要求。由于VO2薄膜的相变温度接近室温,具有良好的光电性能,成为相变材料中最有希望用于红外探测器的激光防护材料。介绍了VO2薄膜的光电特性,并探讨了其在激光防护应用方面的相关问题以及发展前景。     

Pulsed laser deposition and physical properties of carbon nitride thin films

Carbon nitride thin films were grown using an approach that combines pulsed laser deposition and atomic beam techniques. The composition and phases of the carbon nitride materials obtained from the reaction of laser ablated carbon and atomic nitrogen have been systematically investigated. The nitrogen composition was found to increase to a limiting value of 50% as the fluence was decreased for laser ablation at both 532 and 248 nm. Analysis of these experiments show that the growth rate determines the overall nitrogen composition, and thus suggests that a key step in the growth mechanism involves a surface reaction between carbon and nitrogen. Infrared spectroscopy has also been used to assess the phases present in the carbon nitride thin films. This spectroscopic measurement indicates that a cyanogen-like impurity occurs in films with nitrogen compositions greater than 30%. Investigations of the effects of thermal annealing have been carried out, and show that the impurity phase can be eliminated to yield a single phase material. In addition, systematic measurements of the electrical resistivity and thermal conductivity of the carbon nitride films were made as a function of nitrogen content. The implications of these results are discussed.     

Laser processing of high-Tc superconductingthin films

High-T_c superconducting thin films can be deposited and processed by pulsed and CW lasers, and a respectable materials technology for the Y-Ba-Cu-O superconductor is rapidly emerging. The pulsed laser deposition technique is simple because it produces films with compositions nearly identical to those of the target pellets. A larger variety of substrates can be used, compared to other deposition technologies, because of the relatively low temperature requirements. The laser deposition mechanism has been investigated. As-deposited superconducting films, epitaxial films with smooth surfaces, and multilayer structures with abrupt interfaces have been produced. The electrical transport properties can be changed locally using a focused argon-ion laser by modifying the oxygen stoichiometry. This laser writing can be erased by room-temperature exposure to an oxygen plasma. Other laser patterning methods such as material removal, melt-quench, and direct pattern transfer are being developed     

试验卫星激光反射器的设计和试验

MS1和MS2试验星是我国首批设计寿命10年的中高轨导航卫星,为提高在轨精度和实现卫星精密定位,作为舱外有效载荷,两颗卫星均标配搭载了激光反射器。卫星激光反射器光学设计应考虑远场衍射等物理光学影响,不能仅考虑几何光学理论设计。以试验星反射器为例,基于角反射器光学远场衍射能量分布理论为基础,采用最大雷达截面法进行反射器尺寸优化,利用角度补偿法进行速差补偿角设计,对反射器表面加工精度、反射表面特性、切割方式等光学参数进行优化分析计算,并通过合理的机械结构和材料设计,解决了高量级力学环境、330℃高低温度交变、10年空间辐照寿命等环境适应性问题。试验星光学测试结果表明:参数设计合理,可实现远场环带能量在预定观测区域的最大化,在轨观测数据表明反射器工作正常,测距精度、测距范围等指标满足预期设计,理论设计和实践相符,这对今后同类激光反射器的设计具有借鉴和指导意义。     

Structures for organic diode lasers and optical properties oforganic semiconductors under intense optical and electrical excitations

The challenges to realizing diode lasers based on thin films of organic semiconductors are primarily related to low charge carrier mobility in these materials. This not only limits the thickness of organic films to ⩽100 nm in electrically pumped devices, but it also leads to changes in the optical properties of organic films induced by the large number of carriers trapped in the materials subjected to an intense electrical excitation. We describe organic waveguide laser structures composed of thin organic films and transparent indium-tin-oxide electrodes. These waveguides allow for efficient injection of an electrical current into the organic layers and provide for low optical losses required in a laser. The changes in the optical properties of organic thin films induced by electrical excitation are studied using electroluminescence and pump and probe spectroscopy. Induced transparency and absorption observed in the organic materials may be related to triplet excitons or trapped charge carriers. Pump-induced absorption is also observed in organic films under quasi-CW optical excitation. These effects must be taken into account both in the design of organic diode laser structures and in the selection of charge transporting materials     

激光法制备二氧化钒军事防护薄膜研究

二氧化钒(VO2)具有热致半导体—金属相变特性, 其相变温度为 68益, 最接近室温, 可作为理想的光学功能材料, 在军事上有广泛应用前景。脉冲激光沉积法作为一种新型的制膜方法, 相比其他方法具有粒子能量高、可控性强等优点。介绍了 VO2薄膜的光电特性及其在军事上尤其是激光防护领域的应用前景, 并重点探讨了激光法制备 VO2薄膜的相关问题及解决措施。     

皮秒激光直写还原石墨烯氧化物薄膜的研究

利用皮秒激光直写还原绝缘石墨烯氧化物(GO) 薄膜,成功制备了图案化的导电石墨烯。先 通过旋涂法制备GO薄膜,再使用皮秒激光进行直写扫描,可以同步实现GO的还原和图案化 两个关键步 骤。光学显微镜成像显示,还原前后GO颜色发生明显变化,图案结构清晰,分辨率较高。结 合拉曼光谱和 X光电子能谱(XPS)进行表征分析的结果表明,激光直写区域石墨层缺陷程度和 含氧量均明显降低,GO还 原程度较高。图案化还原后GO(RP-GO)薄膜电学测试的结果表明,可以通过 改变皮秒激光 的输出功率对RP-GO的导电性能进行调控。本文技术一次性解决了石墨烯的大规模制备、图 案化成形和电学 性能调控三大难题,开辟了石墨烯基微电子器件生产制造的新道路。     

国外反狙击手光电探测技术与装备

目前反狙击手光电探测主要包括红外探测和激光探测两种手段.以美国、法国、以色列和俄罗斯等国为例,介绍了反狙击手红外和激光探测技术和装备的发展情况.从光电探测材料的进步、各种探测手段以及干扰对抗措施的综合应用、装备平台的拓展、多功能的融合、网络化探测能力的实现等方面,探讨了未来反狙击手光电探测技术和装备的发展方向.