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介绍一种在微波布拉格衍射实验中测量模拟晶体衍射极大值的新方法.此方法是采用微波分光仪自动测试系统进行测量,并且利用绘图软件处理数据,可以同时测量简单立方模拟晶体多个晶面的衍射极大值. 相似文献
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在丝径的激光高精度衍射测量中,激光的偏振方向、光束的几何属性和光束中心对衍射体对称中心的偏离都会影响测量的结果.本文从测量的角度对后二者的影响进行较为深入的研究.在理论研究的基础上,进行了计算机模拟,最后提出处理结果的方法. 相似文献
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凹面衍射光栅兼具色散分光与光束聚焦功能,同时具有像差校正、低杂散光、无鬼线和高信噪比等优势而受到光谱仪器领域的广泛关注。衍射效率作为凹面光栅最重要的技术指标之一,其测量技术水平逐渐成为光谱仪器行业最为关注的课题之一。传统方法一般采用双单色仪结构实现凹面光栅衍射效率的测量,该方法主要存在两方面问题,一是测量标准反射镜和待测光栅的出射光谱带宽不同,二是光栅叠级、杂散光的影响;上述问题的存在降低了高性能凹面光栅衍射效率测量的准确性。本文提出了一种基于傅里叶光学原理测量凹面光栅衍射效率的新方法;针对该方法建立了凹面光栅衍射效率测量的数学模型,并采用光学追迹和傅里叶光学方法相结合对其进行了仿真分析,从而验证了该方法的正确性;针对动镜横移误差、倾斜误差、光源稳定性、动镜运动距离误差等因素影响凹面光栅衍射效率测量精度的问题,提出引入辅助探测器的方法来进一步提高衍射效率测量精度,并对有无辅助探测器情况下的上述误差对衍射效率的影响进行了数学推导和仿真分析,分析结果表明引入辅助探测器可以有效抑制了上述误差对凹面光栅衍射效率测量的影响。对比传统双单色仪测量方法而言,该方法不仅能够解决传统测量方法存在的问题,同时还具有多波长同时测量、高光通量、高分辨率、高波数精度等优势,可以有效提高凹面光栅衍射效率的测量精度和测量效率。 相似文献
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基于快速傅里叶变换的衍射现象的数值仿真 总被引:2,自引:1,他引:1
根据夫琅禾费衍射与傅里叶变换的关系,通过构建数值遮光屏,并利用快速傅里叶变换,可以获得夫琅禾费衍射图样的二维仿真及其相对光强的三维分布图.利用Matlab实现了对单缝、圆孔及多缝的衍射现象的仿真.结果显示,该方法思路清晰,结果准确可靠,可作为教学中分析夫琅禾费衍射现象的另一种有效方法. 相似文献
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一维位置灵敏单丝气体探测器采用单根镀金钨丝和200根阴极感应条的探测结构, X射线在阳极丝上产生的信号被多个阴极条感应, 利用重心法得到X射线的原初电离点的位置信息, 位置分辨率达到160 μm(半高全宽). 在同步辐射衍射实验中, X射线通过样品后会形成不同大小的衍射环, 本实验中测量得到11.148°和14.201°的两组衍射角位置信息; 通过平行移动一维探测器在衍射环范围内多次扫描, 可以重建得到二维衍射环. 由于一维探测器的气体厚度和入射窗宽度会给测量结果带来像差, 分析发现像差的影响大于一维探测器的位置分辨. 基于相应的物理分析对测量到的衍射位置进行修正, 修正后的衍射位置相比修正前的衍射位置的相对像差最大改善达到7%, 该方法实现了无像差二维衍射环的重建. 相似文献
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Yunfeng Bai 《Optics Communications》2011,284(19):4272-4274
A novel polarization measurement approach using multi-slit diffraction method is proposed in this paper. Part of binary grating is covered by one polarizer. And based on Fraunhofer diffraction, the diffraction intensity formula is deduced. Then we can get the polarization state of the incident light by fitting the measured diffraction pattern with theory diffraction intensity formula. This method only uses polarizer, but not 1/4 waveplate, therefore, it can be applied to measure monochromatic light of any wavelength without a replacing device. 相似文献
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Olivier Lazzari Christopher K. Egan Simon D. M. Jacques Taha Sochi Marco Di Michiel Robert J. Cernik Paul Barnes 《Journal of synchrotron radiation》2012,19(4):471-477
A new data collection strategy for performing synchrotron energy‐dispersive X‐ray diffraction computed tomography has been devised. This method is analogous to angle‐dispersive X‐ray diffraction whose diffraction signal originates from a line formed by intersection of the incident X‐ray beam and the sample. Energy resolution is preserved by using a collimator which defines a small sampling voxel. This voxel is translated in a series of parallel straight lines covering the whole sample and the operation is repeated at different rotation angles, thus generating one diffraction pattern per translation and rotation step. The method has been tested by imaging a specially designed phantom object, devised to be a demanding validator for X‐ray diffraction imaging. The relative strengths and weaknesses of the method have been analysed with respect to the classic angle‐dispersive technique. The reconstruction accuracy of the method is good, although an absorption correction is required for lower energy diffraction because of the large path lengths involved. The spatial resolution is only limited to the width of the scanning beam owing to the novel collection strategy. The current temporal resolution is poor, with a scan taking several hours. The method is best suited to studying large objects (e.g. for engineering and materials science applications) because it does not suffer from diffraction peak broadening effects irrespective of the sample size, in contrast to the angle‐dispersive case. 相似文献
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We propose a method for reconstructing a complex field from a series of its near-field diffraction patterns.This method is based on the paraxial Fresnel diffraction equation without making further approximations.Numerical simulations are presented showing that a complex field can even be reconstructed with moderate qualities from its two near-field diffraction patterns and almost exact reconstructions can be obtained when three or more diffraction patterns are used.We also show by numerical simulation that the correct diffraction distances can be recovered in case only coarsely measured values are available.This method may be applied to phase imaging of weak-absorption objects. 相似文献
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利用球面波夫琅禾费衍射放大衍射图样 总被引:1,自引:0,他引:1
基于球面波夫琅禾费衍射原理 ,通过理论推导得出衍射图样线度与障碍物 (被测物 )到像面的距离z成正比 ,而不是与物镜的焦距 f成正比 .因此仅通过移动障碍物 (改变z)即可使衍射图样线度得到放大 .本文以细丝的衍射实验为例进行了验证 ,实验结果表明该方法是可行的 相似文献