Non-contact thickness measurement for ultra-thin metal foils with differential white light interferometry

A new differential white light interference technique for the thickness measurements of metal foil is presented. In this work, the differential white light system consists of two Michelson interferometers in tandem,and the measured reflective surfaces are the corresponding surfaces of metal foil. Therefore, the measuring result is only relative to the thickness but not the position of metal foil. The method is non-contact and non-destructive, it has the advantages of high accuracy, fast detection, and compact structure. Theoretical analysis and preliminary experimental verifications have shown that the technique can be used to measure the thickness of foil in the range of 1 to 80 μm with accuracy better than 0.08 μm.     

利用象增强器构成光电相关鉴相器面阵的研究

本文介绍了利用阴极可控的微通道板象增强器构成面阵型光电相关鉴相器的原理,采用了方波与正弦波相关的方案,在微通道板象增强器的光电阴极加上方波门控电压,把它作为参考信号,测量具有相位差的同频正弦波光信号,研究了它的一些基本特性,给出了这种面型鉴相器的潜在应用.     

采集强干扰下微弱信号的APD电路系统研究

基于雪崩光电二极管反向偏压及其电容特性,利用时间同步原理,构建了一个用于回避强烈反射光信号,探测微弱回波信号的雪崩光电二极管探测系统.对雪崩光电二极管电容效应作出了分析,得出交流高压供电会使雪崩光电二极管产生干扰尖峰脉冲的结论.为了消除这个电容效应产生的尖峰干扰,提出了施加直流反向低压的方案,以达到减少雪崩光电二极管电容变化量的目的.通过实验数据验证了方法可行性.     

Non-contact thickness measurement for ultra-thin metal foils with differential white light interferometry

A new differential white light interference technique for the thickness measurements of metal foil is presented. In this work, the differential white light system consists of two Michelson interferometers in tandem, and the measured reflective surfaces are the corresponding surfaces of metal foil. Therefore, the measuring result is only relative to the thickness but not the position of metal foil. The method is non-contact and non-destructive, it has the advantages of high accuracy, fast detection, and compact structure. Theoretical analysis and preliminary experimental verifications have shown that the technique can be used to measure the thickness of foil in the range of 1 to 80 μm with accuracy better than 0.08 μm.     

A new subdivision technique for grating based on CMOS microscopic imaging

We propose a new subdivision technique directly subdividing the grating stripe by using complementary metal-oxide semiconductor (CMOS) microscopic imaging system combined with image processing. The corresponding optical system, subdivision principle, and image processing methods are illuminated. The relations of systemic resolution to subdivision number, grating period, magnifying power and tilt angle are theoretically discussed and experimentally checked on the Abbe comparator. The measurement precision for displacement of the proposed subdivision system is tested in the range of 5 mm and the maximum displacement error is less than 0.4μm. The factors contributing to the systemic error are also discussed.     

利用红外光谱和窗口因子分析研究加热导致的牛血清白蛋白的二级结构变化

用红外光谱和窗口因子分析(WFA)对加热导致的D2O中牛血清白蛋白(BSA)的二级结构变化进行了研究. 常规光谱分析和WFA的结果表明, BSA的结构变化开始于56 ℃, 而二级结构的剧烈变化发生在68~82 ℃, 与α-螺旋片断相连的短链变化发生的温度比其它二级结构变化的发生温度低10 ℃左右. 研究结果表明, WFA在解析溶液里蛋白质的温度相关红外光谱中起重大作用.     

利用象增强器构成光电相关鉴相器面阵的研究

本文介绍了利用阴极可控的微通道板象增强器构成面阵型光电相关鉴相器的原理,采用了方波与正弦波相关的方案,在微通道板象增强器的光电阴极加上方波门控电压,把它作为参考信号,测量具有相位差的同频正弦波光信号,研究了它的一些基本特性,给出了这种面型鉴相器的潜在应用.     

半正弦波相关型三维激光雷达

提出了基于半正弦波-方波相关法的凝视成像三维激光雷达.用傅里叶级数展开对新方法进行了分析.理论分析表明,半正弦-方波相关可以在抑制高频噪音的同时加大调制的交流分量.基于新相关方法的探测系统可以在不损失测距准确度的条件下可以获得更大的输出光功率从而获得更大的探测距离.采用基于新方法的探测装置对~70 m外约100 m2的目标进行了探测实验.实验结果表明,基于新方法的激光雷达在60 m处的分辨率约为0.3 m,从而验证了理论分析的结论.     

强散射体内部目标的实时高分辨率成像方法

由于强散射介质的散射作用,使得传统光学成像系统难以有效探测其内部目标。针对这一难点,提出了一种对强散射介质内部目标进行高分辨率实时成像的方法。基于强散射介质波前校正原理,采用汇聚照明方式,通过纯相位型空间光调制器,对散射介质表面点目标进行校正,使其清晰成像。在此基础上,保持调制图样不变,将汇聚照明改为扩展照明,即可实现对校正点附近较大视场和景深范围内目标的实时清晰成像。基于此方法搭建的实验系统很好地实现了强散射介质内部目标的实时成像,通过比较传统光学系统在无散射介质条件下和散射成像系统在有强散射介质条件下的成像质量,结果表明,散射成像系统具有更高的成像锐度。