"猫眼"目标回波功率的影响因素分析

光电系统广泛存在着所谓的"猫眼效应",针对"猫眼"目标的反射特性,建立了正负离焦时"猫眼"目标回波发散角数学模型,采用几何光学方法对正入射条件下具有"猫眼效应"光学系统的回波发散角进行了推导,总结出离焦条件下"猫眼"目标的回波功率计算公式,分析了各因素对"猫眼"目标回波功率的影响,并对理论分析的结果进行了验证.结果表明:"猫眼"目标的回波功率受发射激光参数、大气透过率、"猫眼"目标光学系统参数等诸多因素影响,其中压缩激光发散角、提高发射功率能够显著增强回波功率,增加大气能见度和"猫眼"目标反射面反射率同样增加回波功率,而离焦量的增大则会引起回波功率的衰减.     

激光主动侦察技术研究

介绍了“猫眼”效应及激光主动侦察原理,给出了激光主动侦察条件下回波功率计算公式,分析了侦察系统的作用距离,讨论了光学系统离焦量对反射回波的影响,为激光主动侦察问题的深入研究作了有益的探索．     

激光主动侦察作用距离的研究

基于猫眼效应的激光主动侦察技术有效地结合了激光技术、成像传感技术和微弱目标的信息处理技术,可实现对远距离微弱目标的主动探测和识别,是光电对抗领域的一项重要技术,其中作用距离是侦察系统的主要参量之一。为了评估激光主动侦察系统的作用距离,以猫眼目标的光学窗口所反射的激光回波功率为基础,分析了影响作用距离的因素,建立了最大作用距离的数学物理模型,数值模拟了发射激光峰值功率、发射激光束散角、大气能见度、探测器灵敏度以及等效反射面离焦量对最大作用距离的影响。结果表明,通过减小发射激光束散角,提高探测器灵敏度可以有效提高系统的作用距离;为满足不同情况的天气需求,可选择不同波长的激光光源。这一结果可用于指导激光主动侦察的系统设计或者作为衡量系统性能的标准。     

激光主动侦察技术的原理研究

分析激光对“猫眼”类光学镜头的作用距离。推导出激光对“猫眼”类光学镜头的距离方程。阐述激光主动侦察原理：应用脉冲激光测距原理测量目标的距离；光学目标识别的方法包含激光回波信号强度识别法、回波信号脉宽识别法和回波信号追踪识别法。     

猫眼光学窗口反侦测能力影响因素分析

为了提高我军光电对抗能力,达到攻防兼备的目的,必须在开展猫眼主动侦测研究的同时,开展猫眼光学窗口的反侦测策略研究。以探测激光回波功率为主要判断依据,利用数值仿真的方法对反侦测能力影响因素进行了定性和定量分析。结果表明,猫眼回波功率会随着探测器入射光功率、接收光学系统光学窗口面积、发射光学系统透过率、发射激光束发散角、猫眼物镜口径、焦距及反射元件失调量的改变而变化,且受漫反射背景和系统工作波长的影响。对影响因素的分析为反侦测策略的研究提供了理论依据。     

基于"猫眼"效应的激光回波功率理论分析

激光主动侦察技术是利用光电系统的光学窗口对入射激光具有很强的反射回波的"猫眼"效应来实现对复杂漫反射背景中的光学窗口侦察、定位.对基于"猫眼"效应的激光回波功率从理论上给出了详细的公式推导,并进行了应用分析和定量计算.这对激光主动侦察中的激光器功率、作用距离等参数选择有着重要的意义.     

基于APD的“猫眼”目标主动探测系统信噪比分析

信噪比是表征激光主动探测系统性能的重要指标,通过分析雪崩光电二极管(APD)的噪声来源和离焦“猫眼”目标回波功率,建立了APD探测器的信噪比模型,分析了离焦量、目标距离、激光发散角对APD探测器信噪比的影响,并进行了数值模拟分析,结果表明:离焦量的增大会引起“猫眼”目标回波功率变小,进而使APD探测器信噪比减小;“猫眼...     

基于“猫眼效应”的激光主动探测技术应用研究

基于“猫眼效应”的激光主动探测技术,是对无人机光电系统实施强激光干扰较为有效的探测和效果评估方法。基于对光学探测系统参数理论分析,建立了因离焦量而引起的回波发散角及回波功率计算模型。从激光发散角、入射角、反射角等方面研究了激光主动探测技术所受影响因素,为判别干扰是否有效,对激光回波探测功率的影响因素进行细化分析,在仿真条件下计算出激光干扰有效的入射角度范围。     

“猫眼”目标探测距离方程

利用矩阵光学方法对探测过程进行了建模,对探测距离方程进行了推广,使方程适用于猫眼光学系统离焦、探测光束斜入射的一般情况,通过室外探测实验对探测距离方程进行了验证。理论分析和数值计算表明:回波方向相对于入射光方向存在微小的回波方向偏差角,但相同条件下回波发散角要远大于回波方向偏差角,使回波足以形成对探测系统的覆盖;在相同的探测参数条件下,回波功率只与猫眼光学系统焦距和离焦量有关,而与探测光束入射角、猫眼光学系统接收孔径无关。     

红外点源导引头的激光回波分析

为了研究用激光主动扫描法侦察远方飞航导弹来袭方位的原理及实验技术,以红外点源导引头光学系统为例,运用矩阵光学追迹法对影响"猫眼"效应回波强度的因素作定性、定量分析。研究结果表明,回波强度受导引头光路中光学镜头相对孔径、摄像管靶面倾斜和离焦的影响较大,扫描激光光束的入射角等因素对回波强度也有一定影响。在主动扫描装置距被探测导引头约10000m、扫描光束的入射角为0.08rad条件下,反射面离焦及倾斜使得侦察装置接收到的回波能量与发射脉冲能量之比由理想条件下的43.80%分别下降到1.53%和0%。这一结果对"猫眼"效应用于主动式侦察的原理在导弹来袭告警系统中的应用是有帮助的。     

Resolution Enhancement Technology:Integrated Process Solutions using OPC

DUV lithography, using the 248 nm wavelength, is a viable manufacturing option for devices with features at 130 nm and less. Given the low kl value of the lithography, integrated process development is a necessary method for achieving acceptable process latitude. The application of assist features for rule based OPC requires the simultaneous optimization of the mask, illumination optics and the resist.Described in this paper are the details involved in optimizing each of these aspects for line and space imaging.A reference pitch is first chosen to determine how the optics will be set. The ideal sigma setting is determined by a simple geometrically derived expression. The inner and outer machine settings are determined, in turn,with the simulation of a figure of merit. The maximum value of the response surface of this FOM occurs at the optimal sigma settings. Experimental confirmation of this is shown in the paper.Assist features are used to modify the aerial image of the more isolated images on the mask. The effect that the diffraction of the scattering bars (SBs) has on the image intensity distribution is explained. Rules for determining the size and placement of SBs are also given.Resist is optimized for use with off-axis illumination and assist features. A general explanation of the material' s effect is discussed along with the affect on the through-pitch bias. The paper culminates with the showing of the lithographic results from the fully optimized system.     

Cost-effective test solutions for smart card and other integrated flash applications

From its emergence in the late 1980s as a lower cost alternative to early EEPROM technologies, flash memory has evolved to higher densities and speedsand rapidly growing acceptance in mobile applications.In the process, flash memory devices have placed increased test requirements on manufacturers. Today, as flash device test grows in importance in China, manufacturers face growing pressure for reduced cost-oftest, increased throughput and greater return on investment for test equipment. At the same time, the move to integrated flash packages for contactless smart card applications adds a significant further challenge to manufacturers seeking rapid, low-cost test.     

Theoretical analysis of the relationship between the Brillouin gain coefficient and the strain in the optical-fiber sensors

The relation between the power of the Brillouin signal and the strain is one of the bases of the distributed fiber sensors of temperature and strain. The coefficient of the Bfillouin gain can be changed by the temperature and the strain that will affect the power of the Brillouin scattering. The relation between the change of the Brillouin gain coefficient and the strain is thought to be linear by many researchers. However, it is not always linear based on the theoretical analysis and numerical simulation. Therefore, errors will be caused if the relation between the change of the Brillouin gain coefficient and the strain is regarded as to be linear approximately for measuring the temperature and the strain. For this reason, the influence of the parameters on the Brillouin gain coefficient is proposed through theoretical analysis and numerical simulation.     

An improved parallel thinning algorithm with two subiterations

The parallel thinning algorithm with two subiterations is improved in this paper. By analyzing the notions of connected components and passes, a conclusion is drawn that the number of passes and the number of eight-connected components are equal. Then the expression of the number of eight-connected components is obtained which replaces the old one in the algorithm. And a reserving condition is proposed by experiments, which alleviates the excess deletion where a diagonal line and a beeline intersect. The experimental results demonstrate that the thinned curve is almost located in the middle of the original curve connectivelv with single pixel width and the processing speed is high.     

Novel fiber-optical interferometer with miniaturized probe for in-hole measurements

Today, micro-system technology and the development of new MEMS （Micro-Electro-Mechanical Systems） are emerging rapidly. In order for this development to become a success in the long run, measurement systems have to ensure product quality. Most often, MEMS have to be tested by means of functionality or destructive tests. One reason for this is that there are no suitable systems or sensing probes available which can be used for the measurement of quasi inaccessible features like small holes or cavities. We present a measurement system that could be used for these kinds of measurements. The system combines a fiber optical, miniaturized sensing probe with low-coherence interferometry, so that absolute distance measurements with nanometer accuracy are possible.     

Study of waveguide coupling efficiency in hybrid silicon lasers

This paper presents a new method to increase the waveguide coupling efficiency in hybrid silicon lasers. We find that the propagation constant of the InGaAsP emitting layer can be equal to that of the Si resonant layer through improving the design size of the InP waveguide. The coupling power achieves 42% of the total power in the hybrid lasers when the thickness of the bonding layer is 100 nm. Our result is very close to 50% of the total power reported by Intel when the thickness of the thin bonding layer is less than 5 nm. Therefore, our invariable coupling power technique is simpler than Intel＇s.     

Teleportation of an arbitrary unknown N-qubit entangled state under the controlling of M controllers

A new quantum protocol to teleport an arbitrary unknown N-qubit entangled state from a sender to a fixed receiver under M controllers(M < N) is proposed. The quantum resources required are M non-maximally entangled Greenberger-Home-Zeilinger (GHZ) state and N-M non-maximally entangled Einstein-Podolsky-Rosen (EPR) pairs. The sender performs N generalized Bell-state measurements on the 2N particles. Controllers take M single-particle measurement along x-axis, and the receiver needs to introduce one auxiliary two-level particle to extract quantum information probabilistically with the fidelity unit if controllers cooperate with it.     

Diode-end-pumped Nd:YVO4/LBO lasers with 4.2W continuous-wave output at 457 nm

A continuous-wave (CW) 457 nm blue laser operating at the power of 4.2 W is demonstrated by using a fiber coupled laser diode module pumped Nd: YVO4 and using LBO as the intra-cavity SHG crystal With the optimization of laser cavity and crystal parameters, the laser operates at a very high efficiency. When the pumping power is about 31 W, the output at 457nm reaches 4.2 W, and the optical to optical conversion efficiency is about 13.5% accordingly. The stability of the out putpower is better than 1.2% for 8 h continuously working.     

A rigorous proof of MIMO channel capacity’s increase with antenna number

It is well known that adding more antennas at the transmitter or at the receiver may offer larger channel capacity in the multiple-input multiple-output（MIMO） communication systems. In this letter, a simple proof is presented for the fact that the channel capacity increases with an increase in the number of receiving antennas. The proof is based on the famous capacity formula of Foschini and Gans with matrix theory.     

Call for Papers

正Wireless Body-area Networks The last decade has witnessed the convergence of three giant worlds:electronics,computer science and telecommunications.The next decade should follow this convergence in most of our activities with the generalization of sensor networks.In particular with the progress in medicine,people live longer and the aging of population will push the development of wireless personal networks