共查询到16条相似文献,搜索用时 406 毫秒
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提出了利用数字全息干涉术可视化观测液相扩散过程.实验中,采用马赫-曾德干涉仪光路记录乙醇与水之间两相扩散过程的多幅数字全息图;再通过数值再现不同扩散状态的波前相位分布,获得液体中的摩尔浓度分布;最后,根据菲克定律获得两相流扩散系数.结果表明:利用数字全息干涉术可实现对液相扩散传质过程的快速、实时及高精度测量;该方法还具有可实现远程监控、拥有大量微观数据的优点;此外,采用文中全息干涉光路结合波分与角分复用技术可实现多相流扩散系数的测量,为获得溶液中非线性变化特征参量提供了有效技术手段. 相似文献
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利用马赫-曾德尔干涉光路和4f光学透镜系统,以部分畴反转的掺钌铌酸锂晶体(RuO2:LiNbO3)的透射光作为物光来记录全息图,并在数值再现过程对其进行频域滤波以实现物场波前信息的数值重建,检测出在一定电压作用下晶体内部折射率变化的二维分布.检测结果证实:晶体中发生畴反转的区域与发生电色效应的区域严格相符.数字全息干涉术非接触、无干扰、无破坏的优势在准实时监控、检测和分析铌酸锂晶体畴反转方面有很好的应用前景.
关键词:
畴反转
数字全息干涉术
电色效应 相似文献
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电子学全息法再现三维物场 总被引:5,自引:1,他引:4
叙述了一种采用电子学全息法分析三维物场的定量方法,它包括:(1)三维物场全息图的数字记录,2)全息图面上复振幅分布的数字再现,(3)利用空间频域衍射公式计算其它平面上的复振幅分布,由此可以获得整个三维物场的信息。本文同时还给出这一数字再现方法的空间分辨率。最后通过计算机模拟展示了一个理想三维物场的再现过程及再现结果。 相似文献
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利用马赫-曾德尔干涉光路和4f光学透镜系统,以部分畴反转的掺钌铌酸锂晶体(RuO2:LiNbO3)的透射光作为物光来记录全息图,并在数值再现过程对其进行频域滤波以实现物场波前信息的数值重建,检测出在一定电压作用下晶体内部折射率变化的二维分布.检测结果证实:晶体中发生畴反转的区域与发生电色效应的区域严格相符.数字全息干涉术非接触、无干扰、无破坏的优势在准实时监控、检测和分析铌酸锂晶体畴反转方面有很好的应用前景. 相似文献
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数字全息显微术中重建物场波前的相位校正 总被引:10,自引:1,他引:9
数字全息显微术克服了传统光学显微术无法直接提取样品相位信息的缺点,可以对活体细胞组织等相位型生物样品进行定量测量和有效观察。但在数字全息显微成像过程中,像场弯曲会对再现像相位分布的测量和观察产生影响。提出一种采用相位相减来校正数字全息再现像像场弯曲的方法。通过在样品加入前后两次拍摄全息图,并对数值重建像分别进行去包裹运算再令其相减,即可实现对像场弯曲的有效校正,对蝉翼和大蒜表皮细胞等相位型物体进行测量,并采用数值校正和相位相减两种方法对像场弯曲进行校正。与现有的数值校正方法相比,利用相位相减获得样品三维相位信息的方法更为简单、可靠,是校正像数字全息再现场弯曲的有效方法。 相似文献
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The application of digital phase shift holographic interferometry to flow-visualization and flow temperature measurement of a 2D thermal flow field was experimentally investigated. An improved recording system for two reference beam phase shift holographic interferometry is set up for this experiment, and details of this experimental technique are described. The phase distribution obtained by this technique presents an excellent picture of flow visualization. From this phase image, temperature distribution of the 2D thermal flow field is also calculated and compared with some measured values obtained using thermocouple probes. 相似文献
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The electric field distribution in Li Nb O3 crystal under different electrode shape is presented by using the digital holographic interferometry. Three configurations of phase modulator including the rectangular electrode type,single-triangle electrode type, and dual-triangle electrode type are performed in this experiment. The nonuniform electric field distribution in these phase modulators are observed and the electric field increases with voltage increasing. The digital holographic interferometry with high electro-optic effect improves the measurement precision. The digital holographic interferometry provides an effective way for studying the electric field distribution. Such in situ quantitative analysis of electric field distribution is a key to optimizing electrode shape. 相似文献
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Nanoscale deformation measurement by using the hybrid method of gray-level and holographic interferometry 总被引:1,自引:0,他引:1
C.H. Chien Y.D. Wu Y.T. Chiou C.C. Hsieh Y.C. Chen T.P. Chen M.L. Tsai C.T. Wang 《Optics and Lasers in Engineering》2006,44(1):80-91
This study extends the use of holographic interferometry to measure the nanoscale out-of-plane displacement with high surface resolution. It is noted that if the deformation is less than half of the optical wavelength, it is hard to find an obvious fringe pattern. Under such a situation, in general, the phase shift method is used. However, it needs to take more than 3 images for phase shifting and phase reconstruction In this paper, a more simple hybrid method of gray-level and holographic interferometry is used to extract fringe skeletons, in which it just needs to take one or two images for the normal deformation measurement directly, even if there exists no obvious fringe pattern. The displacement field with high surface resolution can also be obtained. The proposed method yielded a theoretical precision of 0.15 nm for out-of-plane displacement with a monochromatic CCD camera of 10-bit gray scale (1024 gray scales) sensitivity and microscale surface resolution for millimeter scale object with 640×480 pixels image resolution by an He–Ne LASER (632.8 nm wavelength) light source. The gray-level method is proposed to calculate the non-obvious interferometry fringe by traditional holographic interferometry hologram, and the result showed that this method works for this purpose. 相似文献
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Puchao Zheng Jianglei Di Wangmin Zhou Hao Wang Ruifeng Zhang 《Optics Communications》2009,282(22):4339-4344
By using digital holographic interferometory with phase multiplication, the visualized measurement of the acoustic levitation field (ALF) with single axis is carried out. The digital holograms of the ALF under different conditions are recorded by use of CCD. The corresponding digital holographic interferograms reflecting the sound pressure distribution and the interference phase distribution are obtained by numerical reconstruction and phase subtraction, which are consistent with the theoretical results. It indicates that the proposed digital holographic interferometory with phase multiplication can successfully double the fringe number of the interference phase patterns of the ALF and improve the measurement precision. Compared with the conventional optical holographic interferometory, digital holographic interferometory has the merits of quasi real-time, more exactitude and convenient operation, and it provides an effective way for studying the sound pressure distribution of the ALF. 相似文献
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While holographic interferometry gives a good picture of the stress distribution over a complex structure, its use in stress-analysis has been limited by the fact that quantitative information on the deformation of the surface is directly available only at points on the fringe maxima or minima, and interpolation between these points is slow and not very accurate. An improved phase-measurement system for real-time holographic interferometry is described. This uses a diode array television camera to view the interference pattern, and digital electronics to calculate and store the phase difference at a 100 × 100 grid of points. This permits measurements of the phase with an accuracy estimated at ±2°. 相似文献
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In this paper a digital in-line holographic recording and reconstruction system was set up and used in the particle image velocimetry for the 3Dt-3c (the three-component (3c), velocity vector field measurements in a three-dimensional (3D), space field with time history (t)) flow measurements that made up of the new full-flow field experimental technique—digital holographic particle image velocimetry (DHPIV). The traditional holographic film was replaced by a CCD chip that records instantaneously the interference fringes directly without the darkroom processing, and the virtual image slices in different positions were reconstructed by computation using Fresnel–Kirchhoff integral method from the digital holographic image. Also a complex field signal filter (analyzing image calculated by its intensity and phase from real and image parts in fast fourier transform (FFT)) was applied in image reconstruction to achieve the thin focus depth of image field that has a strong effect with the vertical velocity component resolution. Using the frame-straddle CCD device techniques, the 3c velocity vector was computed by 3D cross-correlation through space interrogation block matching through the reconstructed image slices with the digital complex field signal filter. Then the 3D-3c-velocity field (about 20 000 vectors), 3D-streamline and 3D-vorticiry fields, and the time evolution movies (30 field/s) for the 3Dt-3c flows were displayed by the experimental measurement using this DHPIV method and techniques. 相似文献