斩波法在激光微能量计标定中的应用

针对激光微能量测量的问题,提出一种激光微能量计标定新方法与装置。研究内容包括使用稳功率连续激光作为光源,通过基于斩波的脉冲发生器组件产生微能量的脉冲激光,分别使用脉冲宽度测量组件与功率测量组件进行采集、软件分析,计算微能量值及通过比对给出待标定能量计的修正系数,计算机自动控制。结果表明,该方法获得的脉冲激光波形稳定,脉冲宽度测量不确定度为0.08%,激光功率测量不确定度为0.25%,实现了对0.1 pJ～1 mJ的激光能量进行准确复现和传递。     

252Cf源驱动功率谱密度法测量系统

介绍了252Cf源驱动功率谱密度法测量原理,采用硬件和软件相结合的方式构建实现了一种实际的测量系统和研究平台,以服务于反应堆核参数测量。描述了基于3通道、1 GHz采样率和1 ns同步精度的超高速数据采集卡的中子脉冲序列检测方法,并设计了PC机端的数据处理流程和功率谱密度分析算法。实际测量结果表明,该252Cf源驱动功率谱密度法测量系统能准确高效地得到核随机过程的相关函数和功率谱密度等重要标签参数。     

An improved maximum permissible exposure meter for safety assessments of laser radiation

Current interest in laser radiation safety requires demonstration that a laser system has been designed to prevent exposure to levels of laser radiation exceeding the Maximum Permissible Exposure. In some simple systems it is possible to prove this by calculation, but in most cases it is preferable to confirm calculated results with a measurement. This measurement may be made with commercially available equipment, but there are limitations with this approach. A custom designed instrument is presented in which the full range of measurement issues have been addressed. Important features of the instrument are the design and optimisation of detector heads for the measurement task, and consideration of user interface requirements. Three designs for detector head are presented, these cover the majority of common laser types. Detector heads are designed to optimise the performance of relatively low cost detector elements for this measurement task. The three detector head designs are suitable for interfacing to photodiodes, low power thermopiles and pyroelectric detectors.

Design of the user interface was an important aspect of the work. A user interface which is designed for the specific application minimises the risk of user error or misinterpretation of the measurement results. A palmtop computer was used to provide an advanced user interface. User requirements were considered in order that the final implement was well matched to the task of laser radiation hazard audits.     

Design of data communication and management system for ground test and verification devices of space laser communication

Verification of a space laser communication system's parts or of component-level, terminal-level, and system-level performance using ground test and verification devices on the ground before launch is vital. In this paper, a data communication and management system is proposed, which is an important part of the ground test and verification devices system and manages the test process and impacts on the measurement results directly. We improved the existing hardware buses to make up the hardware part, and also designed the software part. Several typical tests were performed, and the results show that the maximum time delay is less than 50 ms. The developed data communication and management system is demonstrated to be a high-performance system which can meet the requirements in our project.     

合肥光源单束团下束团长度和能散的测量

根据同步光与储存环中的束流信号具有相同的时间结构的原理,测量同步光脉冲的半高全宽值可以计算出束团的长度。根据合肥光源的特点和实际需要,选择快速光电接收器搭配高速高带宽示波器作为在线测量束团长度和纵向分布等的主要手段。对单束团模式下束团长度随流强和高频腔腔压的变化趋势进行了测量。测量结果表明:束团长度与腔压的0.3次方成反比,比理论值0.5小;而束团长度随流强的增长率为2.0 ps/mA。通过测量纵向量子寿命进行了能散随流强变化的间接测量,结果表明,束团的拉伸是能散变化和势阱效应共同作用的结果。     

基于LabVIEW的超快激光制造系统设计

针对当前大部分超快激光制造系统中存在的三维移动平台控制软件和光学显微镜软件集成化程度低而导致的操作方式繁琐等问题,设计了一种基于LabVIEW软件开发平台的集成化超快激光制造系统控制软件,以实现对超快激光制造系统的高效调控。该系统由飞秒激光器、三维移动平台、在线监测CCD、激光功率计、快门和计算机等六部分构成。设计思路是基于LabVIEW软件平台的多线程编程技术,将飞秒激光束的通断与三维移动平台的移动实现协调控制,采用CCD相机对样品进行对焦和监控加工状态,利用激光功率计对激光功率进行在线监测,并将其集成于同一界面以实现控制。实验证明,与常见超快激光制造系统相比,该系统稳定度高、操作简单、界面简洁、可扩展性强、调节效率高。     

Rapid and flexible laser marking and engraving of tilted and curved surfaces

We present a novel method for rapid and flexible laser marking and engraving of tilted, curved and freeform work-piece surfaces. The method is based on integrating a three-dimensional (3D) laser measurement system into a 3D laser marking system. We use the same laser source and optics for measurement and processing with a minimum of additional hardware components. A low power CW laser regime is used to measure the 3D shape of a work-piece surface while a high-peak power-pulsed laser regime is used for processing. The acquired 3D surface data are used to determine the 3D trajectory of the processing beam focus. Neither the 3D shape of the work-piece nor its orientation needs to be known in advance as long as the processed surface lies within the working range of the 3D laser processing system. This eliminates the need for exact work-piece positioning before processing and substantially improves processing flexibility (allowing, e.g. variations in work-piece shape or/and orientation from mark to mark). This paper discusses key issues concerning an implementation of the method and presents typical examples of markings and engravings, which demonstrate the advantages of the method with respect to the existing industrial 2D and 3D laser marking and engraving methods. The method can also be applied to flexible laser structuring and microprocessing of curved surfaces.     

大功率TEA CO2激光系统的电磁兼容设计

大功率TEA CO2激光系统工作时产生的强电磁干扰主要来源于激光主放电回路、脉冲火花开关和电源。这种强电磁脉冲干扰对激光系统内部及相关外部设备的电子系统具有很大的干扰和破坏作用。对大功率TEA CO2激光系统的电磁干扰进行了分析计算,在此基础上对大功率TEA CO2激光系统进行了EMC设计。硬件设计手段分别采用了对电磁干扰源和控制子系统进行屏蔽、系统合理布局与布线、滤波隔离,软件采用了数据冗余纠错、冗余化操作和数据鉴别等抑噪和纠错技术,有效地抑制了干扰电磁波在系统内外的传播,解决了大功率TEA CO2激光系统EMC问题。结果表明,对电磁干扰源和控制子系统进行屏蔽,系统合理布局与布线、滤波隔离等措施,是抑制电磁干扰,保证激光控制子系统硬件不受损坏的主要手段。软件抗干扰,是硬件抑制电磁干扰措施的补充和延伸,能使激光系统具有很高的可靠性。     

条纹相机系统在激光脉冲整形测量中的应用

针对采用脉冲堆积法进行激光脉冲整形后获取的宏脉冲,介绍了基于条纹相机观测其纵向分布的基本原理。阐述了测量系统中的硬件配置功能以及脉冲堆积原理,并描述了使用条纹相机专用软件测量激光脉冲的详细步骤和操作界面。研究了测量系统中时序控制的调试对观测脉冲堆积后的宏脉冲的影响并给出了测量结果和测量误差分析。结果表明:采用脉冲堆积法所获得的激光脉冲整形效果非常理想,整形前激光脉冲的半高全宽值约为3.82 ps,整形后约为15.3 ps,且平顶部分的脉宽为11.5 ps,上升沿和下降沿均为1.9 ps。     

激光光斑有效面积的准确测定

 从激光光斑有效面积的定义出发，采用CCD图像摄取技术，设计了一套激光光斑有效面积测量装置。在4种不同激光光斑能量分布和不同能量密度的情况下，用有效面积测量仪分别进行了实际测试验证。结果表明，该测量装置可以对任何能量非均匀分布的激光光斑的有效面积进行准确测试，有助于提高光学元件激光损伤阈值的测量精度。     

激光器参数综合检测系统设计

为解决目前各激光器检测仪功能单一、检测精度低等问题,研制了一种新型智能激光器参数检测系统。该系统采用现代控制技术和微机软件,且配有特定结构的分光束光学系统,能同时实现辐射器光轴平行性、光束性能参数（包括光束发散能量、脉宽、编码精度）、光轴稳定性测试和系统整体性能测试。通过引入红外自准直仪使系统的角分辨率达到了2″,借助示波器捕获窄达100ps的激光脉冲,高精度、大动态范围的激光能量计可精确测量出激光的能量。     

激光多普勒测速实验虚拟仿真及硬件改进

针对传统激光多普勒测速实验系统中硬件采样率有限及多普勒信号自动化处理性能较弱的问题,本文开展了实验系统虚拟仿真及硬件改进.利用Unity 3D和Matlab Apps对实验内容及其信号处理方法进行了建模,通过虚拟仿真的开发,学生可更深入地了解实验系统的细节;采用LabVIEW编程和数字示波器组建了便捷的自动化高速数据采...     

Control-It. - A new software concept to control isotope mass spectrometers and preparation lines

A new software, CONTROL-IT, was developed as an easy means to control isotope mass spectrometers and automated sample preparation lines by the user himself. CONTROL-IT makes thoroughly use of the graphical human interface on Apple Macintosh® systems and is written for the Hypercard® environment. Control of the isotope-analytical hardware bases on software procedures passed by name to a do-list which in the automated control mode is evaluated consecutively. CONTROL-IT enables the user to set up the control sequence in all detail himself and lets him readily modify and update his preparation and measuring routines for precise adaption to the analytical demands, experimental evidence, or new developments of his hardware. A schematic representation of the isotope-analytical hardware, composed of interactive icons of the hardware elements, makes the software almost completely screen-operated and provides high flexibility and transparency to the user for interactive assembling of the control sequence as well as for half-automated or full-hand operation of the hardware system or parts of it. - In Kiel, CONTROL-IT is applied to a Delta E spectrometer, an equilibration unit for δ¹⁸O analysis on water samples, and a multiport for external gas samples.     

基于高温超导脉冲变压器的脉冲电源测控系统

为了监测脉冲电源的放电特性、控制脉冲电源的可靠工作,采用现代测试技术、虚拟仪器技术和数据库技术,设计了基于高温超导脉冲变压器的脉冲电源测控系统,硬件系统由计算机、单片机、数据采集卡、驱动电路板和电压电流传感器等组成,软件系统采用LabVIEW来进行设计.在脉冲电源的测量算法中,采用基于EEMD的消噪算法,消除了噪声,采用基于最小二乘法的数据拟合算法,准确的测量出脉冲电源电流的峰值、脉宽等参数.实验结果表明,该系统可以实时监测和控制脉冲电源的工作过程,实现了电参数的在线测量和整体系统的闭环控制.     

双波长LD模块的拉曼光谱测试系统

荧光干扰是拉曼光谱检测过程中常见的干扰因素之一,而移频激发法是一种有效的克服荧光干扰的检测手段。移频激发法利用两个波长相近的激光分别激发被测物质,并将获得的拉曼光谱进行差谱。由于两次激发的荧光背景相同,而拉曼特征峰会产生平移,因此可有效地消除荧光背景的干扰,进而利用一定的算法还原拉曼特征峰。移频激发法的关键在于两个激发光波长的稳定性,不稳定的波长差将严重影响对拉曼特征峰的还原效果。本文研制了一种拉曼光谱测试系统,该系统的双波长LD模块能够产生两个波长稳定的激发光(分别为784.7和785.8 nm),满足移频激发法的测试要求。影响激发光波长稳定性的因素主要是光功率和温度,本系统中对这两个因素均进行了实时的监控,以保证激发光波长的稳定。系统的硬件部分主要包括ARM主控板、双波长LD模块及其驱动电路、温度控制板、数字光开关、光谱检测光路和光纤探头(两个高功率的蝶形封装激光器);软件部分可自动获取被测物质的拉曼光谱图,并对其进行后续的处理。在稳定性测试实验中,对系统驱动电源电流和激光器温度的稳定性均进行了测试。测试结果显示,电流波动范围小于0.01 mA、温度变化范围小于0.004 ℃,能够有效地保证激发光波长的稳定性。最后,对某品牌花生油进行了拉曼光谱检测,并对检测结果进行了处理,获得了良好的效果。     

An opto-electrical method for measuring the gap of LCD glass plates

We focus on the experimented system development for the measurement of the gap of LCD glass plates. The measurement system includes a laser light source, lens module, image capturing system and the algorithm for calculation of the position of light spots. We emphasize the structure of laser triangulation in an optical system. The software is focused on the algorithm for calculating the position of light point, including centroid calculation method (CCM) and Fourier phase shift (FPS).

Furthermore, to verify the feasibility of the algorithm, we use computer software to simulate experiments. We also discuss the contribution of the noise to the accuracy for the CCM and FPS. To complete the development of the opto-electrical measurement system and to verify the accuracy for the hardware architecture, we use a novel mechanism of multi-track and concentricity, laser light source, lens module, and image capturing system.     

激光引信仿真仪的设计

激光引信是制导武器普遍使用的近炸引信,然而模拟真实激光回波信号以及验证信号处理系统的准确性存在一定的困难。在分析激光引信回波功率模拟和回波延迟时间模拟的基础上,推导出数学表达式,并针对具体情况进行了仿真。给出了激光引信仿真仪中的硬件组成以及软件流程图,对激光引信仿真仪的研制具有一定的指导意义。     

激光等离子体光谱测量影响因素分析

建立了一套激光等离子体光谱测量实验装置,以Nd:YAG调Q固体激光器(单脉冲平均能量38 mJ)为激发光源,铜合金为样品,得到了Cu原子辐射谱线随时间的变化情况,分析了系统中软、硬件因素对测量的谱线影响。实验证明激光器输出能量波动、每个数据点的平均次数、靶面相对于透镜焦点的位置、接受辐射的光纤束相对靶面法线的位置以及接受光纤束的有效通光口径都影响测量谱线的强度和重复精度。     

An embedded design for monitoring and controlling temperature

Each and every part of human life is somehow linked with the embedded products. Embedded systems are product of hardware and software co design. It is becoming an integral part of engineering design process for efficient analysis of data acquisition. Data acquisition implies the gathering of information about a system or process. It is the process of collecting data in an automated way from analog and digital sources of measurement, such as sensors and devices under test. The present paper describes the design of an embedded system for the control of temperature and light intensity in a single system using sensors, microcontroller and Liquid Crystal Display (LCD). It describes the controlling action incorporated in the hardware to control any device connected when specific conditions are met.     

355 nm紫外激光损伤阈值自动测量装置及实验

介绍了一套355nm紫外激光损伤阈值自动测量装置。该测量装置由一台Nd：YAG激光器产生紫外355nm激光,经过紫外激光传输系统,紫外激光聚焦形成测试激光。脉冲激光能量由激光能量计监测,Normaski显微镜判断样片的激光损伤。另外,整个测量装置和测量过程由计算机集成控制,具有良好的操作性和运行参数控制能力,可实现1—on-1,n-on-1,s—on—1,R-on-1等多种激光损伤测试。