菲涅耳衍射解析表达式的物理意义

文中讨论了圆孔菲涅耳衍射解析表达式的物理意义,指出了精确解(在菲湿耳近似下)与近似解的区别,并与用数值积分法计算的结果进行比较,证明了圆孔菲涅耳衍射解析表达式的正确性.     

菲涅耳衍射解析表达式的物理意义

文中讨论了圆孔菲涅耳衍射解析表达式的物理意义,指出了精确解(在菲湿耳近似下)与近似解的区别,并与用数值积分法计算的结果进行比较,证明了圆孔菲涅耳衍射解析表达式的正确性。     

菲涅耳圆孔衍射的解析处理

推导了傍轴条件下菲涅耳圆孔衍射场的级数解,进而讨论了一些具有重要理论和实验意义的问题。     

菲涅耳圆孔衍射的解析处理

推导了傍轴条件下菲涅耳圆孔衍射场的级数解,进而讨论了一些具有重要理论和实验意义的问题．     

圆孔的菲涅耳衍射

得到了圆孔菲涅耳衍射光强分布的表达式,此式由贝塞尔函数的数列(或Lommel函数)给出,因此很容易利用普及的数学软件算出结果.并且利用CCD照相机量度了衍射光强分布,与运算的结果作了比较,也与Burch在1985报导的结果作了比较.     

环形光栅的菲涅耳衍射

在圆孔的菲涅耳衍射的基础上 ,讨论环形光栅的菲涅耳衍射 ,并给出了计算机仿真结果     

菲涅耳衍射和分数傅里叶变换

介绍了衍射孔的菲涅耳衍射和分数傅里叶变换的对应关系，使得可以用分数傅里叶变换来描述光电原始光场经过菲涅耳衍射区一直到无穷远处夫琅禾费衍射区的自由空间标量衍射传播全过程。     

菲涅耳轴上衍射场的计算

给出了一种计算菲涅耳衍射的方法,它既能比较精确地计算轴上的衍射场,也能用来近似地估算轴外的衍射场。     

菲涅耳衍射的数值计算

利用Mathematica软件分别计算了单缝衍射及双缝衍射的光强分布,成功解决了菲涅耳衍射的计算这一较难问题,并得到了双缝衍射向杨氏双逢干涉过渡的具体条件,完成了实验室内难以完成的任务.     

验证菲涅耳圆孔衍射中的一个重要结论

验证菲涅耳圆孔衍射中的一个重要结论温淑珍（黑龙江绥化师专）在菲涅耳圆孔衍射中，如图１，圆孔ＣＣ’露出的波阵面，在与点光源Ｐ０处同一轴上的Ｐ点引起的光振动的振幅”’为其中山和山分别为波阵面上相对于ＰＯ和Ｐ所作的第一个和最后一个菲涅耳半波带单独对该点引起...     

Angular criterion to distinguish between Fraunhofer and Fresnel diffraction

The distinction between Fresnel and Fraunhofer diffraction is an essential condition for the accurate analysis of diffracting structures. In this paper we propose a criterion based on the angle subtended by the first minimum of the diffraction pattern from the centre of the diffracting aperture. The determination of the minimum of the diffraction pattern is the crucial point to assure the accuracy of the criterion. Therefore, the applicability of adequate thresholds for detection is discussed. The criterion is also generalized by expressing it in terms of the number of Fresnel zones delimited by the aperture. Simulations are reported to illustrate the feasibility of the criterion.     

菲涅耳微透镜列阵衍射效率的测试与分析

归纳了目前二元位相型菲涅耳微透镜列阵衍射效率测试中所用各种衍射效率的不同定义，提出规范定义的建议。并设计了测量衍射效率的系统，方法简单易行，适于测试具有微小单元尺寸的菲涅耳微透镜列阵的衍射效率。     

正多边形和狭缝的等效菲涅耳数

以正边形的内切圆半径和狭缝的半宽度为特性尺度,给出了匀幅平面波入射时正多边形和狭缝的等效菲涅耳数。     

用多重菲涅耳衍射变换和相位密码板实现图像加密的技术

基于多重菲涅耳衍射变换和相位密码板,设计了一种新的图像加密计算方法.待加密的明文图像在多重离散菲涅耳衍射变换和相位密码板的共同作用下,变换为一个具有随机码特征的密文矩阵;衍射距离和相位密码板是主要的密钥.只有当所有密钥都正确时,才能成功地解密密文.结果表明,该加密算法能抵抗JPEG有损压缩、图像剪切、重度噪音污染和重采样等攻击,因此该法具有较强的鲁棒性;由于很难破解多重密钥,所以该算法具有极高的安全性.     

衍射理论公式的诠释与应用

对基尔霍夫衍射理论几个积分公式的导出与使用给予详细说明与解释,并列举了它们的部分应用.     

对实屏的夫琅禾费衍射中心亮点(亮纹)的半定性半定量论证

光经圆盘、细丝等实屏衍射后,衍射光场中其几何阴影中心有不为零的光强分布.显然这是阐述光的波动性的最好例证,它比圆孔、单缝之类的光孔衍射更具说服力.然而对圆盘等的衍射中心亮点(如泊松点)的论证通常都是从菲涅耳衍射出发,但是在绝大多数非物理类专业的大学物理中,对光的衍射的具体分析都只涉及夫琅禾费衍射,因而给学生对于上述问题...     

3D Reconstruction of Large-Depth Objects Using Fresnel Diffraction of a Ronchi Grating and Simultaneous Recording of Reference and Object Fringes

We propose an active triangulation based range-finding system that, besides its simplicity, has two advantages over similar existing systems. First, the system can acquire range data for large-depth objects since it generates an illumination pattern with large-depth of focus using Fresnel diffraction from a Ronchi grating projected over the entire object surface. Secondly, the system does not need preliminary recording of reference fringes since it displays simultaneously, on a single image, both reference and object deformed fringes. This system offers other properties: it is mechanically simple, uses everyday optical components, is low cost, can be operated via a PC and uses relatively simple image analysis software. Three dimensional reconstructions are illustrated for various objects having 10 cm maximum depth variations. The depth accuracy (typically 0.5 mm for an object located at 350 mm from the camera) is comparable with other systems, but a certain compromise has to be accepted in acquisition time (typically 1 minute). This system can find applications in research laboratories as a tool to provide range data with relatively good depth accuracy.     

Relations between chirp transform and Fresnel diffraction, Wigner distribution function and a fast algorithm for chirp transform

Two physical interpretations of chirp transform related to Fresnel diffraction and Wigner distribution function are given.The chirp transform can be regarded as a Fresnel diffraction observed on a spherical tangent to the diffraction plane,or a rotation and stretching transformation of the Wigner distribution function space.A general fast algorithm for the numerical calculation of chirp transform is developed by employing two fast Fourier transform algorithms.The algorithm,by which a good evaluation can be achieved,unifies the calculations of Fresnel diffraction,arbitrary fractionalorder Fourier transforms and other scalar diffraction systems.The algorithm is used to calculate the Fourier transform of a Gaussian function and the Fourier transform,the Fresnel transform,the Fractional-order Fourier transforms of a rectangle function to evaluate the performance of this algorithm.The calculated results are in good agreement with the analytical results,both in the amplitude and phase.     

Theoretical analysis for surface tilt and translation detection based on speckle photography in the Fresnel domain

The theoretical and numerical analysis in this work show that both surface tilting and translational motion can be simultaneously calculated using the speckle photographic technique by recording consecutive speckle pattern images in two different Fresnel diffraction distances. A simulation example based on the proposed scheme is given to verify the method’s validity and high accuracy of the calculated motion detection. Compared with other previous works the results show that this method is efficient and easy to implement.