室内大面积激光测速光幕光能均匀性研究

针对大横截面室内靶道弹丸测速需求,提出采用一字线激光器作为光源,L形排布的光电二极管阵列作为接收的室内大面积矩形探测区域激光测速光幕构建方法,对光幕面内光能分布均匀性进行理论分析及实验研究。在单个一字线激光器光能分布理论分析基础上,通过实验验证了理论分析的正确性,并对两个一字线激光器拼接作为光源的1m×1m靶面的激光测速靶靶面内光能分布均匀性进行了实测研究,对实验结果进行了分析。该研究成果为实用室内超大面积激光测速光幕靶的设计提供了理论及数据参考。     

大靶面激光光幕靶研究

针对大靶面、高精度弹丸速度测量的要求,提出一种新型激光光幕靶弹丸速度测量系统。该系统采用大功率90°扇形线状激光器做为光源,两列高灵敏度光电二极管阵列作为接收装置,当弹丸穿越激光光幕面时,遮挡了部分投射在光电二极管上的光线,光电二极管产生微弱电信号,经放大、整形后输出一个脉冲信号,触发计时仪开始或停止计时。两台同样的装置配合测时仪,便可组成激光光幕靶测速系统。经实弹实验证明,该系统具有高灵敏度和高精度的特点。     

高功率XeCl准分子激光系统前端平滑实验

为得到物面光强分布均匀、能量尽量大的部分相干XeCI准分子激光前端种子光,采用放大自发辐射(ASE)法和散射法开展了前端平滑实验研究.首先,基于一台窄脉冲XeCl准分子激光器,研究了种子光的物面光斑均匀性、能量和发散角随光束口径及物面位置的变化规律.然后,分析了影响种子光参数的因素.最后,进行了验证实验.实验结果显示:...     

基于垂直腔面发射半导体激光器的自混合测速实验

针对激光自混合速度传感应用,采用新型垂直腔面发射激光器作为自混合干涉系统光源,对采用不同散射表面类型和工作电流所获得的自混合测速实验结果进行了研究.研究结果表明,黑色相纸材质的散射表面会对自混合信号产生不利影响;选择激光器的工作电流在阈值电流1～1.4倍时能获得较大且稳定的自混合信号.考虑该测速系统实际应用中存在开机预...     

箭靶照度的分析

研制了射箭动态精度激光测试系统。以He一Ne激光器为光源计算了距靶面50m、25m和5m处光斑照度的数值,并与室内外标准照度值作了比较,指出实验工作应以室内为宜。     

大面积三角组合光幕弹幕武器密集度的高精度测试

提出了一种交叉布置的大面积三角组合光幕的高精度激光靶密集度测试方法,以解决超高射频弹幕武器立靶密集度测试的难题。给出了激光器、激光光束整形系统、激光探测器阵列组成的大面积三角光幕光电开关系统设计方案,分析了双大面积三角光幕测量原理,推导出了三角光幕弹着点坐标解算方法。结合系统采用的探测器件输出特性分析了该测试方法的误差,结果显示:当规则靶面区域宽度从3.6 m扩展到10 m时,最大测试误差从0.557 mm变为0.832mm,只增加了0.275mm,实现了很高的测量精度。模拟射击试验结果表明,采用分辨率为1.6mm的探测器阵列时,X坐标最大误差为0.747mm,Y坐标最大误差为0.635mm,实现了对超高射频弹幕武器立靶密集度的高精度检测。该测试方法具有光幕面积大、测量精度高、安装调试方便的特点。     

提高杂光系数测量用积分球装置中照明均匀性的理论分析与实验

本文从积分球的基本理论出发,作一些简化和近似,分析了改进杂光系数与像面照度分布测量用积分球装置照明均匀性的途径,并结合研制ZG—2型杂光测定仪的具体实践,进行了实验和讨论。结果表明,使照明光源朗伯化是最重要的解决办法。由此,在直径1.6m的积分球内,半球上面的亮度均匀性偏差可小于±3%,远优于国际标准草案的要求。     

光幕靶探测灵敏度与响应时间测量方法

基于光幕阵列构建的光幕靶可用于弹丸的飞行速度、着靶坐标和飞行速度方向角的测量。光幕靶的探测灵敏度决定了其能探测飞行物体的最小尺寸,响应时间决定了可探测物体的最高飞行速度,是光幕靶的核心性能参数。通过分析光幕靶输出的过靶信号特征,建立光幕靶工作机理的数学表达式,提出了一种采用直流电机控制旋转码盘模拟辐射光能量的瞬态变化过程,可快速测量光幕靶的幅频特性参数。研究的方法也适用于其他光电探测仪器的动态响应特性测试领域。     

九光幕阵列测量终点弹道弹丸飞行参数方法研究

终点弹道段弹丸飞行速度低,受外界因素影响弹丸运动轨迹为变速曲线运动,六光幕阵列测量模型无法准确测量弹丸的飞行参数,针对此类问题,提出一种九光幕阵列测量方法。在现有六光幕阵列阵形上增加了3个与原有光幕对应平行的光幕,通过两点速度衰减公式计算出飞行弹丸的阻力加速度,修正弹丸运动曲线方程,利用六光幕阵列测量公式,实现任意方向飞行弹丸飞行参数的准确测量。结合12.7 mm全弹道测速试验,验证了阻力加速度计算方法的有效性,采用七光幕阵列测量4.5 mm气枪弹着靶坐标,与纸板靶上的弹孔坐标进行比对,在2 m×2 m靶面内坐标测量误差小于3 mm。研究的方法拓宽光幕阵列在终点弹道测量领域的应用,特别适用于弹道系数未知的特种弹丸飞行参数测量。     

高功率CO_2激光对远场HgCdTe探测器的干扰实验

理论分析和实验研究了高功率CO2激光对远场光导型长波红外HgCdTe探测器的干扰损伤。采用激光辐照探测器的温升理论模型,根据实验参数,讨论了高功率激光对长波红外探测器的损伤机理,计算了温升与辐照时间和功率的关系,并和CO2激光器在距离15km处辐照光导型长波红外HgCdTe探测器的实验结果进行对比分析。实验结果表明,2.5kW连续CO2激光经过大气衰减后在15km处激光功率密度可达0.161W/cm2,计算可知此时会聚到探测器靶面处的功率密度为140W/cm2;靶面处功率密度为20.5W/cm2时,对探测器产生干扰;靶面处功率密度为110W/cm2时,达到损伤,计算此时探测器表面温度已达到Hg析出温度,这一实验现象和理论计算预期结果相吻合。实验结论对研究探测器的激光防护和激光干扰星载探测器技术具有指导意义。     

小型化弹丸速度测试系统

提出了一种基于光幕测速和单片机数据处理的小型化的弹丸速度测试系统。采用半导体激光器、光电探测器、原向反射屏形成大面积光幕测试区,当弹丸穿越光幕时,光通量的变化被光电探测器转变为电信号,经过比较电路后送入单片机进行数据处理,并由LED进行速度显示。文中对测试原理和测试系统的光学设计单元、信号处理单元及数据采集、显示单元进行了介绍,并对该系统进行了壬7．62mm弹丸速度测试,给出了测试数据。试验表明,该测速系统具有灵敏度高、体积小、成本低、使用方便、灵活、工作可靠等优点。     

基于Mie散射的水中油污在线检测技术研究

近年来,陆地、海洋等水体频发漏油污染事件,水中油类污染检测刻不容缓。基于Mie散射原理,提出了一种采用近红外光散射技术实现水中矿物油含量在线检测方法。近红外半导体激光器(LD)发射光照射在待测溶液上,在线阵CMOS感光器件上接收到被测溶液前向小角度连续点散射光,分析、处理散射光分布数据,从而确定水中矿物油的种类及其浓度。实验测定了不同浓度不同种类矿物油样本的散射曲线,验证了理论分析的结果。设计的近红外光散射技术可用于水中油含量的在线监测。     

A Novel Approach for Warhead Fragments Velocity Measurement Based on Laser Screen

The velocity of warhead fragment is key criteria to determine its mutilation efficiency.We have designed an optoelectronic system to accurately measure the average velocity of warhead fragments.The apparatus including two parallel laser screens spaced apart at a known fixed distance for providing time measurement start and stop signals.The large effective screen area is formed by laser source,retro-reflector and large area photo-diode with a central hole.Whenever a moving fragment interrupts two optical screen,the corresponding photometers senses the event,due to partial obscuration of the incident energy.Experiments have been performed to measure velocity of the different kinds of projectiles and fragments within various size and velocity ranges,including 7.62 mm bullet shooting experiments,prefabricated steel-ball exploding experiments.They were proved that the system is adequate to measure the velocity of larger than 5 mm,less than 1 000 m/s in the range,when fixed trajectory,test the velocity of the projectile average relative deviation is less than 4.21%.The system can perform satisfactorily with a lot of advantages such as larger effective light screen area,quick response speed,low uncertainty,strong repetition and reliability,etc.     

人眼安全的生物气溶胶短程遥测系统

建立了满足激光辐照人眼安全要求的便携式生物气溶胶短程遥测系统,用于实现有人员活动区域生物战剂气溶胶的实时预警监测。以高频调制的405nm半导体激光器为激发光源,200mm口径的卡塞格林望远系统为信号光收集系统,搭建了基于伪随机调制的便携型生物气溶胶激光雷达短程遥测系统。该系统具备平行偏振散射、垂直偏振散射光探测,以及450nm和530nm两个波段荧光探测等四个同步探测通道。以枯草芽孢杆菌、金黄色葡萄球菌和酵母菌为样本对该激光雷达系统进行了初步测试。外场试验表明,该生物气溶胶遥测系统的空间分辨率为1.5m,荧光通道的探测距离为100m;3种被测生物气溶胶种类识别的回代误报率分别为9%、11.5%和14.5%,交叉误报率为11.3%。该遥测系统的激光能量低于激光辐照人眼安全标准的要求,基本实现了生物气溶胶的甄别。     

均匀光强分布的5kW半导体激光硬化光源研制

随着半导体激光自身输出功率和转换效率的提升,半导体激光已经广泛的应用于激光加工领域。本文针对目前激光加工领域对半导体激光硬化光源的需求,研制了波长为976nm的连续输出半导体激光硬化光源。该光源采用空间/偏振合束工艺达到了较高的合束效率,采用柱面微透镜阵列分割与聚焦镜复合较好地匀化了巴条激光器慢轴方向固有的光强起伏,使聚焦光斑的光强呈平顶分布。最后对该光源进行了实验装调和测试。结果表明,在工作电流为93A时,光源的最大输出功率为5 120W,电光转换效率达47%,光斑尺寸为2mm×16mm,光斑分布为平顶分布,平整度大于90%,满足工业中对大面积、高效率激光硬化的要求。     

LDA耦合系统透镜导管的理论与实验研究

用光线追迹的方法,理论推导了透镜导管各参数优化的一般公式,给出了优化参数;在此基础上,模拟了导管内光线的传输,统计了透镜导管出射光束的强度分布,讨论了各参数对耦合效果的影响。依据理论优化的结果,设计加工了透镜导管并进行了耦合实验,测量了输出光束的强度分布,给出了光斑图像。实验测得耦合效率高于91%,输出光束强度分布平滑均匀,光斑质量良好,与理论模拟吻合并优于以往的研究结果。     

Study of the focused laser spots generated by various polarized laser beam conditions

In this work, three‐dimensional near‐field imaging of the focused laser spot was studied theoretically and experimentally. In the theoretical simulation, we use the electromagnetic equivalent of the vectorial Kirchhoff diffraction integral to calculate the intensity distribution of the focal region, and a high depolarization is found in high numerical aperture systems (NA = 0.85). The experimental set‐up is based on a near‐field scanning optical microscope (NSOM) system. A high‐NA objective lens is used to focus incident light of various polarizations, and a tapered near‐field optical fibre probe of the NSOM system is used to determine the intensity of the focal field. The results show an asymmetric distribution of the focused intensity with the linear polarized laser beam.     

Proton emission from thin hydrogenated targets irradiated by laser pulses at 10(16) W∕cm2

The iodine laser at PALS Laboratory in Prague, operating at 1315 nm fundamental harmonics and at 300 ps FWHM pulse length, is employed to irradiate thin hydrogenated targets placed in vacuum at intensities on the order of 10(16) W∕cm(2). The laser-generated plasma is investigated in terms of proton and ion emission in the forward and backward directions. The time-of-flight technique, using ion collectors and semiconductor detectors, is used to measure the ion currents and the corresponding velocities and energies. Thomson parabola spectrometer is employed to separate the contribution of the ion emission from single laser shots. A particular attention is given to the proton production in terms of the maximum energy, emission yield, and angular distribution as a function of the laser energy, focal position, target thickness, and composition. Metallic and polymeric targets allow to generate protons with large energy range and different yield, depending on the laser, target composition, and target geometry properties.     

Concentration measurement with optical fibers for small sample

It is valuable to physically detect concentration of small quantity of liquid with suspended particles. In this paper, light scattering in different directions and optical lengths is simulated and analyzed based on Mie theory. Then, an equipment is designed with two receiving beams of optical fibers, one is for scattering and the other is for transmitting. Scattering angle can be adjustable in order to locate the most sensitive direction. The method of ratio of scattering light to transmitted light is used to reduce the influence of fluctuations of light source and the method of transmitting light is used to satisfy the large measure range. Under room temperature conditions, concentration of yeast extract is tested with 785 nm laser. The results indicate at 0 to 5%, there is linear relationship between ratio of scattering light to transmitted light and concentration. While, for 5 to 10%, there is linear relationship between transmitting light and concentration. Furthermore, it’s notable that maximum relative error on experiment is less than ±0.2%.