基于衍射光栅的二维纳米位移测量技术

提出了一种基于正交衍射光栅作为测量基准元件的二维激光干涉测量系统.利用正交光栅的空间对称级的衍射光进行干涉,基于多普勒效应,采用偏振检测的方法获得相位相差90°的干涉信号.通过光电检测把获得的正弦和余弦信号进行相位细分,系统可在平面二维方向上实现纳米级的分辨率.该系统相比其他干涉测量系统,测量结构紧凑,环境因素对其影响较小,可应用于较大行程的平面微位移精密检测.     

基于二维朗奇光栅的表面形貌测量

本文提出一种采用二维朗奇光栅测量物体表面三维形貌的方法及装置,用一块二维朗奇光栅可同时获取被测表面在两正交方向上的梯度信息,从而仅需一张朗奇光强图便可重构出被测表面的形貌.文章介绍了方法的原理及二维朗奇光栅的结构设计,并用本方法研制的仪器进行了静止的和缓变的表面形貌的测量,取得了良好的测量结果.     

一种简单的二维零位光栅编码新方法

二维零位光栅可以给出标志二维坐标系下绝对零位的脉冲,但由于编码设计的计算量巨大,产生二维零位光栅的编码非常困难.本文结合全局优化的DIRECT算法和遗传算法等优化算法,提出一种首先采用优化算法设计较为易于得到的一维零位光栅编码,然后通过简单的矢量运算扩展为二维零位光栅的编码方法.通过验证,利用该方法所设计的二维零位光栅编码能在满足零位信号对比度与优化设计的一维零位光栅编码相同的前提下有效降低二维零位光栅编码设计的计算量.     

衍射光栅的运动速度与多普勒频移信号的测量

一、前言利用激光多普勒效应进行气体液体和固体的速度测量,已在国内外得到广泛的重视和研究,并已将此新技术用于科研和生产。但是,通过测量激光的多普勒频移值△f,来求运动体的速度,其测速精度将受激光波长、接收方向及双光束夹角等换算因子精度的影响。衍射光栅多普勒频移信号△f,可由双光栅干涉系统产生,它所得到的多普勒信号和入射光的方向及光波波长均没有关系,只决定于光栅常数和光栅的运动速度。通过分偏振移相,还能得到四个90°相移的干涉信号,可直接用计数示波器和李沙育图形测量光栅的运动速度。因此,利用衍射光栅测量运动物体的速度     

一种单透射光栅多普勒效应速度测量装置

本文介绍一种新的测试方法,利用光栅运动的多普勒效应,实现速度或位移测量的单光栅测量系统。     

二维傅里叶变换法三维曲面检测

对投影光栅方法获得的位相调制空间载波图进行二维数字图象处理,实现了散射物体的三维曲面测量,利用二维快速傅里嚅变换将空域信号转变为频域信号,对一级频谱进行傅里叶反变换,逐步解调出其位相值,重建了被测物体表面的形貌。文中给出了对人体模型的实验测量结果。     

垂准仪校准装置的溯源与研究

本文从垂准仪校准装置的应用原理出发,主要针对主标准器为二维光栅坐标靶的垂准仪校准装置,提出一种应用激光干涉仪对垂准仪校准装置校准的方法,进行相关实验并对实验结果进分析。实验结果表明:在恒温条件下,利用激光干涉仪对二维光栅坐标靶的校准可获得高精度的测量数据,在此基础上评定与分析其测量结果不确定度优于10μm(k=2),为深入研究垂准仪校准装置的溯源问题奠定了良好的基础。     

激光多普勒测量技术及其应用

从光学结构、信号处理、方向辨别三个方面综述了激光多普勒测量技术的研究，最后讲述了激光多普勒测量技术在散射体位移测量中的一个实际应用──空间滤波的仿光栅散射体多普勒测量。     

二维精密工作台测量系统设计

提出二维精密微动工作台的结构及控制方案。以直线电机作为驱动,由气浮导轨带动工作台实现水平x、y两个方向微位移运动,同时利用光栅传感器构成反馈控制。z方向采用激光位移传感器,实现非接触测量。     

新型二维电容位置传感器

新型二维电容位置传感器ＭＨｗ。Ｂｏｎｓｅ等１．前盲目前，人们对二维（ＺＤ）位置测量越来越感兴趣。尤其是在ＩＣ生产、生物医学和各种显微技术领域中。迄今，基本的线性位置测量系统主要基于光栅或激光干涉方法，用这些系统可以达到此目的。这些系统在一些应用中也存...     

远红外光光栅光谱仪测量误差分析

采用平面闪耀光栅作为光谱元件的远红外光谱测量原理,分析了四种主要的重复性误差:光栅常数制造误差、零点标定误差、转角测量误差、入射光束与衍射光束的夹角测量误差。 并分别以112.5mm、40.05mm、25mm和12mm的四种闪耀波长为例,计算出了它们的误差传递系数曲线,根据误差传递系数对光谱仪进行误差分配,分析和计算表明:当光栅转角测量精度为1,光栅常数误差为0.5mm时,光谱仪可以满足l/100的波长测量误差要求和l/200的波长重复性测量误差要求。     

成像式光栅自准直测角方法研究

针对目前光电自准直仪难以做到既有高分辨力同时又有大的测量范围的不足,提出一种成像式光栅自准直测角方法。该方法将成像式光栅方法、自准直测角技术相结合,利用标尺光栅像和指示光栅形成的光栅副反映被测物体的角度变化。试验结果表明,该系统接收到的光栅信号稳定,满足光栅计数的要求,成像式光栅自准直测角方法原理可行。该方法避免了光栅副间隙带来的误差,具有大量程及较高的分辨力。     

高密度栅测应变

将高密度光栅应用于力学参量的测量中。通过测得试件变形前后正交光栅衍射点阵的偏移移量，可逐点得到试件因载荷作用而引起的面内应变、离面位移和刚体传动分量。     

衍射频谱法测光栅膜层厚度

根据傅立叶光学理论从光栅的衍射频谱中可以反推光栅本身的多种信息,包括其形貌特征。 利用矩形相位光栅的傅立叶变换,推导出零级和一级衍射光强和矩形相位光栅膜层厚度之间的函数关系,据此可在测得零级和一级次光强后,推算出光栅膜层厚度。以台阶仪作为标准,该方法的测量误差在4%以内。     

Optical grating diffraction method: from strain microscope to strain gauge

The grating diffraction method for direct strain measurement is reviewed. Two systems which use this method are presented. The first system is a compact strain microscope. A Leitz optical transmitting microscope with white light source is reconstructed by developing a loading and recording system. Gratings with median density of between 40 and 200 lines/mm are used. With the help of a Bertrand lens, the Fourier spectrum of the grating is formed with high image quality on the CCD sensor plane. Software is developed to precisely, quickly and automatically determine the diffraction spot centroids. The second system is a new strain sensor based on a high-frequency grating and two Position Sensor Detectors (PSDs). The grating, attached to the surface of the specimen, is illuminated by a focused laser beam, generally with a frequency of 1,200 lines/mm. The centroids of diffracted beam spots from the grating are automatically determined using two PSD sensors connected to a personal computer. The shift of diffracted beam spots due to specimen deformation is detected. Strain sensitivity of one micro-strain can be obtained, as can a 0.4 mm spatial resolution for strain measurement. The system can be used for both static and dynamic tests.     

Zonal wavefront sensor with reduced number of rows in the detector array

In this paper, we describe a zonal wavefront sensor in which the photodetector array can have a smaller number of rows. The test wavefront is incident on a two-dimensional array of diffraction gratings followed by a single focusing lens. The periodicity and the orientation of the grating rulings of each grating can be chosen such that the +1 order beam from the gratings forms an array of focal spots in the detector plane. We show that by using a square array of zones, it is possible to generate an array of +1 order focal spots having a smaller number of rows, thus reducing the height of the required detector array. The phase profile of the test wavefront can be estimated by measuring the displacements of the +1 order focal spots for the test wavefront relative to the +1 order focal spots for a plane reference wavefront. The narrower width of the photodetector array can offer several advantages, such as a faster frame rate of the wavefront sensor, a reduced amount of cross talk between the nearby detector zones, and a decrease in the maximum thermal noise. We also present experimental results of a proof-of-concept experimental arrangement using the proposed wavefront sensing scheme.     

Light coupling into an optical microcantilever by an embedded diffraction grating

By measuring the excitation efficiency of an optical waveguide on a diffraction grating one can accurately register the changes in the incidence angle of the exciting light beam. This phenomenon was applied to detect ultrasmall deflections of silicon dioxide cantilevers of submicrometer thickness that were fabricated with corrugation on top to act as diffraction grating couplers. The power of light coupled into the cantilevers was monitored with a conventional photodetector and modulated using mechanical vibration of the cantilever, thus changing the spatial orientation of the coupler with respect to the incident light beam. The technique can be considered as an alternative to the methods known for detection of cantilever deflection.     

A holographic method for studying absorptivity modulation in transparent media

A dual-beam holographic method is described that can be used for measuring small induced absorptivity modulation in a transparent medium. The proposed method is based on a diffraction-interference scheme in which the interference field inducing an amplitude grating is shifted by a quarter of period relative to a reference volume phase grating. The induced amplitude grating introduces a nonequivalent energy exchange between the transmitted beams, which is proportional to changes in the absorption coefficient of the medium. The new dual-beam holographic method of measuring small absorptivity modulation is compared to the well-known single-beam diffraction technique.     

Segmented chirped grating for coarse wavelength division demultiplexing with multimode optical fibers

A chirped grating segmented into partitions each having a constant blaze angle to use in a demultiplexer for coarse wavelength division multiplexing with multimode optical fibers is developed. Its designed configuration utilizes a resonance region to achieve high diffraction efficiency and large dispersion. The width, blaze angle, and diffraction order of each partition were optimized by vector diffraction analysis. The diffraction loss of the manufactured grating was less than 1.5 dB, and polarization-dependent loss was less than 0.6 dB within a wavelength width of at least 70 nm. It is confirmed that a demultiplexer with the developed chirped grating had a wide passband and low cross talk.     

改进型双光栅矩阵运算光纤光栅传感器

在光纤光栅传感器的应用中一直存在着交叉敏感问题,必须采取各种措施进行补偿或区分。 在悬臂梁的上下两面分别粘贴光纤光栅,通过分别测量这两个光栅的波长位移的改进型双光栅矩阵运算法来克服交叉敏感问题。该方法只需要一套光源和检测系统,装置简单,具有较低的成本和实际应用前景。