线阵推扫式激光成像引信探测技术

针对环视扫描式激光成像引信探测存在着需要光机扫描和较高的激光脉冲重复频率等问题,提出了一种线阵推扫式激光成像引信探测模式并分析了其探测机理.以对坦克目标探测为例,设计了线阵推扫式激光成像引信探测系统,该探测系统采用线阵半导体激光器阵列发射脉冲激光,线阵光电探测器阵列并行接收来实现一维扫描,弹的飞行实现另一维扫描,在获取目标距离信息基础上进行成像.在对阵列单元激光脚印尺寸大小计算的基础上,确定了该探测系统的基本参数包括所需线阵元数、生成图像大小,半导体激光器阵列的脉冲重复频率和峰值功率等,为系统的工程实现提供了理论依据和设计指导.     

飞秒激光并行光学存储系统设计及仿真

针对三维光存储串行写入方式存储速度慢、效率低的缺点,设计了一种飞秒激光并行存储光学系统.该系统以TI公司的数字微镜器件作为空间光调制器,对入射飞秒激光进行调制,并利用微透镜阵列对调制后光束进行分束聚焦,从而产生可控的多焦点阵列,实现可控性强、灵活性好的并行加工.本文利用ZEMAX和Matlab对DMD进行了仿真建模,并...     

基于ZEMAX的自聚焦透镜设计

自聚焦透镜主要应用于光纤传输系统中。自聚焦透镜材料能够使沿轴向传输的光产生折射,并使折射率的分布沿径向逐渐减小,从而实现出射光线被平滑且连续的汇聚到一点。自聚焦透镜是光纤传输系统中构成准直、耦合、成像系统的主要部分。本文主要简要概述基于ZEMAX的自聚焦透镜设计。     

采用组合透镜阵列准直半导体激光器线阵

为了满足半导体激光器线阵的远距离应用要求,需要对激光束进行准直处理.提出了一种由垂直双半圆柱透镜组合阵列构成的准直器,采用光线追迹的方法推导了激光束通过准直器的传输方程,分析了光线出射角与透镜阵列参数之间的关系,得出了准直器的最优设计参数,然后在zemax-EE非序列模式下仿真了此准直器的三维效果图以及探测器成像效果,得到的激光光斑接近于矩形,非相干照度集中在中央区域,并且经过准直器后的发散角大约为3 mrad.设计的准直透镜可以同时压缩快慢轴的激光束发散角,制作简单,安装方便.     

单层曲面复眼成像系统的优化设计

与传统曲面复眼结构不同,提出了在曲面基底上设计非均一微透镜阵列的构想.整个透镜阵列呈环状对称分布,沿径向排列的各级透镜其焦距由所处位置决定,与基底到光探测阵列的距离相吻合.根据几何光学成像原理计算了各级透镜的设计参数并通过光线追迹加以验证.仿真结果表明,这种设计可对全视场在光探测阵列上聚焦,解决了传统曲面复眼边缘视场成像质量急剧下降的问题.同时还论证了采用光刻胶热熔法在曲面基底上制作非均一微透镜阵列的可行性.     

基于微透镜阵的外腔谱组束系统光束质量分析

针对基于微透镜阵的光纤激光外腔谱组束系统的光束质量评价问题,利用高斯光束的传输变换理论,建立了评价谱组束激光光束质量的理论模型.通过数值模拟,详细分析了各相关参数对谱组束光束质量的影响,结果表明:在基于微透镜阵的谱组束系统中,离焦量、微透镜焦距及模场半径是影响谱组束激光光束质量的主要因素;阵列宽度对谱组束激光光束质量影...     

高斯光束到光纤的单透镜耦合

分析了基模高斯激光束到单模和多模光纤的单透镜耦合过程中的各种损耗,把多模光纤的光场用高斯分布近似,采用模场耦合理论计算了基模高斯光束到单模和多模光纤的单透镜耦合效率.模拟计算了当激光-光纤耦合系统的工程参数(光束束宽、光纤数值孔径和光纤的纤芯芯径)一定时,单透镜耦合效率与所选用透镜的焦距之间的关系.并利用532mn激光(M2≤1.05)在几种不同焦距的透镜下对纤芯直径为3.μm的单模光纤和25μm的多模光纤进行了耦合效率的测定实验,得到了与理论计算基本吻合的实验结果.     

大口径多孔透镜离轴成像研究

设计并采用微细加工技术制作了直径D=50mm,特征尺寸为10μm的大口径多孔透镜(photon sieve).在一定的视场下采用数值计算和实验方法分析了其聚焦特性和MTF曲线,为克服多孔透镜一级衍射效率较低,成像质量受背景光干扰的影响,采用了同轴和离轴成像实验.实验结果与聚焦特性一致,两种实验方法得出的不同实验结果表明:离轴成像系统效果克服了同轴成像受0级背景光的影响,改善了像质,为很多一级衍射效率较低的衍射透镜成像提供一种新的成像方式.     

基于无源耦合技术的高速并行光接收模块的设计与实现

提出了一种实现高速并行光接收模块中光电探测器(PD)列阵与光纤列阵精密无源耦合对准的方法,设计并制作了用于这种光学精密对准的所有组件,并用此耦合对准方法完成了PD阵列与光纤阵列之间的光耦合,制作出了12信道并行光接收模块.耦合完成的PD列阵与光纤列阵的对准误差小于1μm,从光纤列阵耦合进入PD列阵的光功率耦合效率大于8...     

两探测面结构激光粒度仪的接收光路设计

为了扩大激光粒度仪测量的动态范围,采用同轴的两组接收透镜,将两个硅光电探测器阵列分别置于前组透镜的后焦面和两组透镜的组合后焦面上,对测量信号进行组合后用改进共轭梯度法处理数据。通过优化光路结构,采用两组双胶合透镜和探测环半径均不大于45mm的探测器可满足同时测量5～3500μm粒径的要求。     

用于对空探测的激光成像雷达设计

本文提出了线阵扫描式激光成像雷达的组成方案,对激光发射、成像接收、分析处理等各个分系统的设计方法进行了详细探讨.以此为依据并且充分考虑了各种参数之间的相互关系,设计出一个原型系统.该系统采用32维APD线列器件,工作波长1.064μm,扫描机构为一维振镜.     

Three-dimensional imaging laser radar with a photon-counting avalanche photodiode array and microchip laser

We have developed a threedimensional imaging laser radar featuring 3-cm range resolution and single-photon sensitivity. This prototype direct-detection laser radar employs compact, all-solid-state technology for the laser and detector array. The source is a Nd:YAG microchip laser that is diode pumped, passively Q-switched, and frequency doubled. The detector is a gated, passively quenched, two-dimensional array of silicon avalanche photodiodes operating in Geigermode. After describing the system in detail, we present a three-dimensional image, derive performance characteristics, and discuss our plans for future imaging three-dimensional laser radars.     

激光相干阵列成象雷达系统光束整形的研究

激光相干阵列成象雷达系统中本振光波前与信号光波前匹配与否直接影响系统的灵敏度和分辨力。采用共轭光栅合成技术对相干成象本振光束作整形处理，以适应探测器件列及合成输出满足最佳信噪比条件。     

Obscuration-free pupil-plane phase locking of a coherent array of fiber collimators

Control methods and system architectures that can be used for locking in phase of multiple laser beams that are generated at the transmitter aperture plane of a coherent fiber-collimator array system (pupil-plane phase locking) are considered. In the proposed and analyzed phase-locking techniques, sensing of the piston phase differences is performed using interference of periphery (tail) sections of the laser beams prior to their clipping by the fiber-collimator transmitter apertures. This obscuration-free sensing technique eliminates the need for a beam splitter being directly located inside the optical train of the transmitted beams--one of the major drawbacks of large-aperture and/or high-power fiber-array systems. Numerical simulation results demonstrate efficiency of the proposed phase-locking methods.     

Planar reflection grating lens for compact spectroscopic imaging system

A compact spectroscopic imaging device consisting of a planar reflection grating lens, a probe fiber array, and a two-dimensional image sensor was proposed and discussed. Reflected or luminescent lights from a subject are coupled to the probe fibers, guided to fiber output ends, radiated into the air, diffracted by the grating lens with wavelength-dependent angle, and focused onto lines on the image sensor. Two-dimensional intensity distribution on the image sensor can give one-dimensional spectrum distribution along a specified direction. A grating lens was designed with a fiber array and a CCD image sensor for 100-nm wavelength range and 10-mm fiber array width. A spectral resolution of 5 nm and a spatial resolution of 0.25 mm were experimentally confirmed.     

应用于激光雷达的光学相控阵技术

以激光雷达作为主要应用背景,概述了光学相控阵技术的研究意义和研究进展。介绍了光学相控阵技术的基本原理;依据几种典型材料对光学相控阵的技术方案进行分类,并详细阐述了各种方案的机理、所涉及的关键技术和最新的研究成果;对各种方案进行了分析、对比和评价。最后,对应用于激光雷达的光学相控阵技术的发展作了展望。     

一种新型雷达天线折叠机构研究与实现

为实现大尺寸平面阵列天线雷达的海陆空多种运输方式兼容,特别是铁路运输时直接驶上平板车,采用了一种新型的前翻四连杆折叠机构。着重介绍了该机构中以液压油缸作为驱动源的四连杆折叠机构的工作原理和结构设计,分析了折叠机构运动规律和受力情况,并在折叠机构系统设计中采用驱动源同步来实现两套折叠机构在展开与折叠过程中实时同步。该机构成功用于某高机动雷达的大型平面阵列天线折叠,通过长期使用证明机构性能良好、可靠性高。     

High-frequency ultrasound annular-array imaging. Part I: array design and fabrication

This is Part I of a series of two papers describing the development of a digital high-frequency, annular-array, ultrasonic imaging system. In this paper, the design and fabrication of a high-frequency annular array as well as its performance will be reported. A six-element, 50 MHz array, which incorporated an acoustic lens to provide an initial focal point, was designed and fabricated. A submicron size grain lead titanate piezoelectric ceramic was used to both reduce lateral coupling and keep the electrical impedance matched close to the 50 ohm receive electronics. The array elements were isolated using laser micromachining to fully separate the annuli, and electrical interconnection was achieved by directly soldering thin wires to the elements. The resulting array attained an average impulse response that exhibited a 43 MHz center frequency, 30% relative bandwidth, and an average insertion loss of 31 dB at 45 MHz. Maximum next-element crosstalk was -27 dB in water.     

Multifunctional catheters combining intracardiac ultrasound imaging and electrophysiology sensing

A family of 3 multifunctional intracardiac imaging and electrophysiology (EP) mapping catheters has been in development to help guide diagnostic and therapeutic intracardiac EP procedures. The catheter tip on the first device includes a 7.5 MHz, 64-element, side-looking phased array for high resolution sector scanning. The second device is a forward-looking catheter with a 24-element 14 MHz phased array. Both of these catheters operate on a commercial imaging system with standard software. Multiple EP mapping sensors were mounted as ring electrodes near the arrays for electrocardiographic synchronization of ultrasound images and used for unique integration with EP mapping technologies. To help establish the catheters' ability for integration with EP interventional procedures, tests were performed in vivo in a porcine animal model to demonstrate both useful intracardiac echocardiographic (ICE) visualization and simultaneous 3-D positional information using integrated electroanatomical mapping techniques. The catheters also performed well in high frame rate imaging, color flow imaging, and strain rate imaging of atrial and ventricular structures. The companion paper of this work discusses the catheter design of the side-looking catheter with special attention to acoustic lens design. The third device in development is a 10 MHz forward-looking ring array that is to be mounted at the distal tip of a 9F catheter to permit use of the available catheter lumen for adjunctive therapy tools.