非近轴条件下无损测量毛细管管壁折射率

提出了一种简便和精确地计算毛细管管壁折射率的方法,该计算方法可在实际非近轴情况下减小图像球差和景深对测量结果的影响.用两种已知折射率的标准液体分别注入待测毛细管内,测量出平行光经其会聚后的焦距差;结合毛细管管壁折射率与焦距的理论公式,计算出毛细管的管壁折射率.结果表明:在合适的毛细管内外径范围内,可以保证管壁折射率在1.51以下时测量准确度优于0.003.对计算方法的分析表明,选取两种低折射率或高折射率液体作为标准液体进行计算可以提高测量准确度.该方法计算过程简单,对毛细管管壁折射率的测量精度满足一般科研实验对毛细管管壁折射率的要求.     

透明毛细管管壁折射率的无损测量

介绍了一种无损测量透明毛细管管壁折射率的方法。该方法利用平行光经过装有不同已知折射率标准液体的毛细管后会聚焦点位置不同的原理,通过CCD对会聚焦点位置成像后的图像进行判断,计算出毛细管外轮廓位置和焦距,进而计算出毛细管管壁的折射率,其测量精度可达0.005。分析了毛细管内外径对管壁折射率测量的影响,结果表明,管壁越厚,测量精度越高;同时对毛细管管壁折射率灵敏度和成像系统的景深值进行了计算和比较,结果显示,标准液体折射率越低,标定精度越高。该方法使用设备简单,操作方便,便于对图像观察和识别,实现了对毛细管管壁折射率的无损精确测量。     

精确测量微量液体折射率的新方法

介绍了一种用玻璃毛细管精确测量微量液体折射率的新方法.该方法基于共轴球面光学系统的成像原理,通过读数显微镜对吸入待测液体后毛细管的焦点位置进行单一参数的测量,进而计算出待测液体的折射率.用此方法测量了纯水、乙醇、乙二醇、丙三醇的折射率,各种待测样品的需要量＜0.002 ml;测量结果表明,纯水和乙醇样品的折射率测量精度优于0.000 3;乙二醇和丙三醇样品的折射率测量精度优于0.000 7.选用适当的毛细管参数,可以进一步提高这种测量方法的测量精度,扩展折射率的测量范围.分析和讨论了实验测量误差以及进一步提高测量精度的方法.该方法具有待测液体用量极少、使用设备简单、操作方便和折射率测量精度高的特点.     

毛细管成像法精确测量微量液体的折射率

介绍了一种用玻璃毛细管成像法精确测量微量液体折射率的方法及测量装置.该方法以充人透明液体的毛细管构成柱透镜,基于共轴球面光学系统的成像原理,对光学成像系统的放大率进行单一参数的测量,进而计算出待测液体的折射率.测量了纯水、乙醇、乙二醇、丙三醇的折射率,各种待测样品的需要量均小于0.002 mL,结果显示本试验装置的测量准确度与目前商用阿贝折射仪(±0.000 2)相当.另外,测量了不同浓度的乙二醇水溶液的折射率,并对测量的数据点进行了曲线拟合,测试结果与阿贝折射仪测量结果和理论公式计算结果所拟合曲线吻合完好.该方法具有待测液体用量极少、操作方便和折射率测量精度高的特点,适用于微量液体折射率的精确、快速测量.     

用显微镜简捷测量液体折射率的浓度

根据光学原理,推导出测量液体折射率公式。利用显微镜和一简单容器,通过一次测量,可求得液体折射率,由折射率可进一步求得有关液体浓度。方法简便、容易,是非接触测量,可用于在线检测,在生产和实验工作中有应用价值。     

国外动态

激光技术的应用之一就是用激光多普勒速度计来测量液体和固体的速度。它采用非接触法进行测速。投影透镜把两个激光光束聚焦在一个靶上。在测量半透明液体时,接收透镜把发射并向前散射的光汇集在一起并聚焦在光电探测器上。散射光和非散射光在光电探测器上混合以后就产生了一种等于这两种光的频差的电信号。在测量表面不透明物体的速度时,接收器和发射器均在物体的表面的一侧,但都采用相同的原理。不透明表面物体的所测速度与检测     

一种精确测量微量液体折射率的新方法

摘 要：本文介绍了一种用玻璃毛细管精确测量微量液体折射率的新方法。这种方法基于共轴球面光学系统的成像原理,通过读数显微镜对吸入待测液体后毛细管的焦点位置进行单一参数的测量,进而计算出待测液体的折射率。用此方法测量了纯水、乙醇、乙二醇、丙三醇的折射率,各种待测样品的需要量小于0.002 ml;对纯水和乙醇样品,折射率测量精度优于0.0003;对乙二醇和丙三醇样品,折射率测量精度优于0.0007。选用适当的毛细管参数,可以进一步提高这种测量方法的测量精度,扩展折射率的测量范围。该方法具有待测液体用量极少、使用的设备简单、操作方便和折射率测量精度高的特点。论文对实验测量误差以及进一步提高测量精度作了详细的分析和讨论。     

气溶胶颗粒折射率在光学粒径测量中的影响

针对单颗粒光散射测量方法中被测颗粒折射率会影响测量结果的问题,根据Mie理论和光辐射能通量计算公式,对13种常见气溶胶颗粒,在不同采光中心角θ和采光接收半角β下的散射光辐射能通量F与粒径D关系曲线进行了计算,提出一种基于相对测量误差平均值的评价标准,依据该评价标准定量分析了13种折射率对测量的影响。通过对模拟结果的分析,得出采光结构接收到的光辐射能通量包含前向散射光的条件下,13种颗粒的F-D曲线较为接近,折射率对测量结果的影响相对较小。     

基于后向光散射的颗粒测量技术研究

颗粒粒径和颗粒折射率是光散射颗粒测量技术中的重要参数。为了实现颗粒粒径的测量及其分档,在广义Mie理论基础上,分析了颗粒粒径及折射率对后向散射光能分布的影响,并得到了后向散射光能分布随颗粒粒径及折射率呈周期变化规律。实验验证结果表明,后向散射光能与颗粒粒径及颗粒浓度有关。研究结果可为后续的颗粒测量研究提供参考。     

工件表面粗糙度的在线测量技术

提出一种基于激光散射法的在线测量方法,以条形激光光束作为光源照射被测物表面,然后用配有高倍率镜头的工业相机采集散射光的图像,最后通过计算机数据处理得到表面粗糙度值.实验证明,该测量方法具有测量速度快、仪器结构简单、非接触且能直观显示被测工件的表面形貌等优点.     

A modified Jelley refractometer

Light beams are read directly (not as virtual images) against a scale erected about 74 cm in front of the prism, with a modified Jelley refractometer. Liquid temperatures are controlled by thermistors placed at each end of the prism trough, which is enclosed in an aluminium block. The scale is calibrated against the refractive index (RI) of distilled water, seven (sic) RI estimates for six Cargille liquids related to six glass standards, and the label RIs of ninety-eight other Cargille liquids. The calibrated refractometer is used accurately and precisely to calibrate ninety-six Cargille liquids, over the inclusive 1?400–1?800 (25?0°C, 589?3 nm, RI unit) label range, at liquid temperatures of 19–49°C and illuminating wavelengths of 435?8–694?3 nm.     

一种基于光电探测技术的非接触式液位监测法

为了实现非接触式液位监测,现基于光电探测技术,针对不同液位状态下光线横穿透明容器后的出射光强进行分析,使用MatLab软件仿真并通过相关实验验证.结果表明:液位下降过程,输出光强会出现脉冲.通过监测该脉冲,间接实现非接触式液位监测,该方法不会造成溶液成分的改变,工作稳定,性能可靠,并能进行功能性扩展.     

Performances of interferometric optical transmission diagnostic for in situ and real-time control of magnetron sputtering deposition process

A convenient and simple in situ and real-time method to control PVD processes for transparent thin films deposition on transparent substrate is described in this paper. This method designed for the glass industry and tested today in on-line monitoring, allows to control the thickness and complex indices and then the good running of the treatment. This method consists of a simple measurement of the interferential transmission through the substrate and the deposit. After recalling the principles of this classical method, the optical sensitivity parameters linked with the use of an inverse calculation method are evaluated and commented on. It is shown that, as expected when the refraction index values of the deposited material are close to those of the substrate, the sensitivity of the process control is low. It is often the case for the deposits used in the glass industry. Nevertheless to exploit this very useful method of process control, a solution currently tested on production lines is described here. To boost the sensitivity of the interferential transmission diagnostic it is shown that the measurements can be made through a high refractive index thin film layer, pre-deposited on the substrate with an adequate thickness.     

Three-dimensional refractive images for laser measurements techniques

A new technology of visualization and diagnostics of transparent media with gradient inhomogeneities is described. This technology is called three-dimensional laser diffractometry; it is based on refraction of spatially structured laser radiation and digital recording and processing of two-dimensional (in transmitted light) or three-dimensional (in scattered light) refractive patterns. Results of computer simulations of three-dimensional refractive patterns (3D refractograms) for spherically and plane layered media are presented. A setup for observation of 3D refractograms in scattered light is schematically described, the method of obtaining refractograms from experimental two-dimensional refractive patterns is presented, and examples of computer processing of experimental data are given.     

On the influence of lipid‐induced optical anisotropy for the bioimaging of exo‐ or endocytosis with interference microscopic imaging

Some implementations of interference microscopy imaging use digital holographic measurements of complex scattered fields to reconstruct three‐dimensional refractive index maps of weakly scattering, semi‐transparent objects, frequently encountered in biological investigations. Reconstruction occurs through application of the object scattering potential which assumes an isotropic refractive index throughout the object. Here, we demonstrate that this assumption can in some circumstances be invalid for biological imaging due to the presence of lipid‐induced optical anisotropy. We show that the nanoscale organization of lipids in the observation of cellular endocytosis with polarized light induces a significant change in far‐field scattering. We obtain this result by presenting a general solution to Maxwell's equations describing light scattering of core–shell particles near an isotropic substrate covered with an anisotropic thin film. This solution is based on an extension of the Bobbert–Vlieger solution for particle scattering near a substrate delivering an exact solution to the scattering problem in the near field as well as far field. By applying this solution to study light scattering by a lipid vesicle near a lipid bilayer, whereby the lipids are represented through a biaxial optical model, we conclude through ellipsometry concepts that effective amounts of lipid‐induced optical anisotropy significantly alter far‐field optical scattering in respect to an equivalent optical model that neglects the presence of optical anisotropy.     

内表面污染物的低相干光干涉检测法

为检测透明容器内表面是否存在污染物,建立了基于容器壁内表面反射的低相干光干涉测量系统。实验采用宽带低相干半导体激光光源和改进的迈克尔逊干涉仪。将测量臂光路对准透明容器,并调节参考臂的光程,使容器内表面反射光的光程与参考臂反射光的光程相等,并出现干涉现象,捕捉并记录此动态干涉信号。经MATLAB软件处理并提取此信号,根据干涉光强度的不同即可辨别透明容器内是否存在污染物。该检测法可为生物医学、食品质检等领域检测透明容器内表面污染物提供一种方便快捷的新方法。     

Application of frustrated total reflection for studying cells in vitro

A mathematical analysis of the dependence of the light flux scattered upon frustrated total reflection (FTR) on the angle of incidence of the light beam is presented for monolayers of spread and spherical cells. It is shown that using these relationships it is possible to estimate the refractive index of hyaloplasm at cell-substrate contacts and to study the flattening of the cell surface facing the glass. Analysis of FTR for single cells is presented. A condition is given that must be fulfilled for the brightly shining regions of the cell to be interpreted as the sites of attachment of the cell surface to glass. The condition defines the range of angles of incidence at which FTR does not depend on the optical properties of the cytoplasm portion being at a distance from the glass. The fulfillment of this condition is necessary for spectroscopic and ellipsometric studies of cell surface contacting the glass, by means of FTR. The conclusions are confirmed by experimental data. A peculiarity of light scattering by cells, associated with the coherence of the incident light beam is discussed.     

Limitations on optical sectioning in live-cell confocal microscopy

In three-dimensional (3-D) live-cell microscopy, it has been common to treat cells as having a constant refractive index (RI). Although the variations in RI associated with the nucleus and other organelles were recognized from phase- and differential interference contrast (DIC) images, it was assumed that they were small and would not affect 3-D fluorescence images obtained using widefield/deconvolution, confocal of multiphoton imaging. This paper makes clear that this confidence was misplaced. Confocal images made using backscattered light (BSL) to image the flat, glass/water interfaces above and below living microscope specimens should reveal these structures as flat and featureless. That the image of the interface on the far side of the cells is neither flat nor featureless indicates that the "optical section" surface can be profoundly distorted by the RI irregularities associated with the presence of nuclei and other subcellar structures. This observation calls into question the reliability of images made using any of the current methods for performing 3-D light microscopy of living cells.     

基于视觉的折射误差校正在位移测量中的研究

非常温环境中,保温装置的光学玻璃给摄影测量引入了玻璃折射误差。为了解决折射误差对位移测量精度影响,通过折射光路分析得到偏移误差模型,并结合曲面拟合法提出校正方法。实验表明,折射误差只与玻璃参数(折射率和厚度)和拍摄距离有关,且校正后的测量方法可以有效地改善玻璃折射影响,提高位移测量精度。