机械准直器的发展

介绍了机械准直器的基本结构和它的性能特点,在机械准直器从产生到现在的理论发展过程中,经历了几何光学、物理光学以及傅里叶光学的发展阶段,总结了各个发展阶段的对机械准直器的理论解释以及实验结果。在此基础上,对机械准直器的傅里叶光学理论的进一步发展提出了看法,并讨论了采用二维傅里叶光学模型所要解决的问题及解决方法,以及二维傅里叶光学公式计算的可行性。     

夫琅禾费缝衍射的计算机模拟

在大学物理的教学中, 夫琅禾费衍射是波动光学的教学重点之一. 以夫琅禾费衍射的光学模型为基 础, 根据傅里叶光学理论给出夫琅禾费衍射光强分布的一般公式, 利用 MAT LA B软件对单缝、 双缝、 多缝以及十字 缝和＝ ‖字缝等缝衍射屏的夫琅禾费衍射进行模拟, 并对计算机模拟结果作出分析. 缝衍射实验的计算机模拟结果 显示快速且清晰, 衍射条纹分布符合衍射规律, 实现了对实际光波衍射的模拟     

数字化光学元件中黑栅效应的研究

计算机光学元件是纯相位元件,能够产生任意形状的波面分布,但存在着加工工艺过于复杂的缺点。目前出现了用数字化元件实现计算机光学元件的方法,在这些方法中经常要面临黑栅效应的干扰。利用傅里叶光学理论研究了黑栅效应对具体元件的影响程度,找出了影响黑栅效应强弱的因素,并用MATLAB软件进行了模拟。模拟结果表明:减小黑栅的宽度可使光能量向接收屏中央集中,有效降低黑栅效应的干扰。     

阿贝成象原理和空间滤波——一个有关傅里叶光学的教学实验

光学信息处理(或称傅里叶光学)为近廿年以来光学中一个迅速发展的新分支。最近出版的国内外高等学校光学教科书中也常单列一章介绍傅里叶光学的一些基本概念及其应用。但新接触这一领域的学生,对于空间频率、空间频谱、空间滤波、卷积等概念的接受,往往不很容易。有必要在学习有关理论的同时,做一些实验。本文所介绍的实验是普通物理光学实验的一个题目。教学对象为物理类各专业的学生。学生在做实验前应有一些理论上的准备(例如听了6—8小时有关课     

被动测距系统的数字图像生成模块设计

为了检验和优化被动测距系统的设计,利用傅里叶光学理论设计并实现了一种数字图像生成模块,在给定光学系统参数条件下,模拟得到了系统的光学传递函数、点扩散函数等重要特性,在两种不同的光电被动测距方案下对该系统进行了系统仿真实验,实验结果验证了模块设计的合理性.     

傅里叶光学算子描述方法的应用

使用傅里叶算子描述方法对通常的4f相干光学处理系统和一线多通道处理系统进行了分析,表明了这一方法对处理复杂的级联系统和含有非球面元件的系统的适用性,为将来用算子方法系统地描述傅里叶光学理论及分析光学处理系统进行初步尝试。     

评<近代光学信息处理>一书 (宋菲君和S.Jutamulia合著,北京大学出版社出版)

《北京大学物理学丛书》第一辑中的《近代光学信息处理》一书与我们见面了．作者以简捷的笔法论述了光学信息处理的各个分支以及相关领域的基本理论及其重要的应用．书中概览了光学信息处理前沿领域的重要研究成果和本学科近期发展动向．作者的论述简明严谨、自成体系,也包括了他们自己多年来在该领域中的科学研究成果、学术贡献和独到的见解．信息光学是近代光学的一个重要的主题,而信息光学的精髓便是“近代光学信息处理”．近代光学信息处理的基础是傅里叶光学．书中的第一章非常简要地阐述了傅里叶光学基础,从二维傅里叶分析的扼要叙…     

全息图的计算机模拟及重现

根据光学全息原理,分析了在计算机模拟中把物光、参考光和再现光离散化的方法,并对基元全息和无透镜傅里叶全息进行模拟,实验结果逼真,这有助于学生更好地理解全息摄影的相关理论,为光学全息的理论和实验教学提供了可视化的验证。     

光的偏振与色散

O436.3 2004064046 用多级台阶量化相位光栅分离偏振光=Polarization demultiplexing with multilevel phase grating[刊,中]/张耀举(温州师范学院物理与电子信息科学系.浙江,温州(325027)),白建平…∥光学技术.—2004.30(4).—495-497,501 构造了三角形轮廓多级台阶量化相位光栅模型,用傅里叶光学方法详细推导了光栅衍射场强的解析表达式。分析了这种光栅对偏振光的分离和聚焦特性,并优化设计了两个光栅。数值模拟和分析表明,模型光栅能     

激光散斑漂移现象的理论模型与成像实验

基于傅里叶光学原理,建立了数值计算客观及主观激光散斑图样的方法.利用几何光学成像原理,推导了主观散斑现象中散斑及光斑漂移速率的表达式.搭建了成像实验装置,观察主客观散斑及其漂移现象.结合相关函数、快速傅里叶变换算法以及卷积定理,建立了基于图像处理定量计算散斑及光斑漂移量的方法.实验结果、数值计算结果、几何光学理论均互相符合,表明了数值方法与几何光学理论的正确性,为激光散斑漂移现象提供了系统性的研究方法和直观的理解.     

Analysis of eccentric photorefraction by Fourier optics

Eccentric photorefraction usually is used as early eyesight diagnostic test of infants and small children. Unlike currently approved geometrical optical model of eccentric photorefractometer, the crescent formation and the light-intensity distribution in the pupil image of a myopic eye are analyzed by Fourier optics with the assumption of an isotropic scattering retina. In the case of little circular light source and rectangular slit, the simulation results of different myopic diopters are obtained by geometrical optical theory and Fourier optics respectively. It is found that the simulation results by Fourier optics are similar as those obtained by geometrical optics, and all simulations are almost corresponding to the experimental result.The result demonstrates that the new method presented here is feasible.     

Characterization of freeform optics in automotive lighting systems using an Optical-Geometrical Feature Based Method

The use of freeform optics has been more widespread. It is difficult to evaluate the optical performance of the freeform optics due to its geometrical complexity. This paper presents a novel method named Optical-Geometrical Feature Based Method (OGFM) for the characterization of freeform optics. The method attempts to establish the relationship between the geometrical features of freeform surfaces (e.g. the surface roughness and form error) and their corresponding optical performance. Hence, the optical performance of the freeform optics can be evaluated by the measurement of the geometrical features which is relative easy to be carried out as compared to the optical performance tests conducted in automotive lighting systems. A series of simulation experiments have been conducted on the freeform optics in an automotive lighting system. The results show that the geometrical errors in micrometer scale appear not to have significant effect on the optical performance of the freeform optics. However, the optical performance is adversely affected when the geometrical form error increases from more than tens of micrometers scale to sub-millimeters scale. The successful development of the proposed OGFM provides an important means for the optimization of manufacturing tolerance, the selection of appropriate optics manufacturing process, and the evaluation of the optical performance evaluation of the freeform optics.     

全息滤波光学图像相减

基于傅里叶光学二次滤波技术,本文提出了一种新的光学图像相减方法,即全息滤波光学图像相减法,该方法需用图像的逆转和匹配两种滤波器和一个8f光学系统,实验表明,作为一种新的图像相减方法,避免了以往实时法对光程的精细控制,因而降低了对辅助设备和环境的要求.     

The fractional Fourier transform as a simulation tool for lens‐based X‐ray microscopy

The fractional Fourier transform (FrFT) is introduced as a tool for numerical simulations of X‐ray wavefront propagation. By removing the strict sampling requirements encountered in typical Fourier optics, simulations using the FrFT can be carried out with much decreased detail, allowing, for example, on‐line simulation during experiments. Moreover, the additive index property of the FrFT allows the propagation through multiple optical components to be simulated in a single step, which is particularly useful for compound refractive lenses (CRLs). It is shown that it is possible to model the attenuation from the entire CRL using one or two effective apertures without loss of accuracy, greatly accelerating simulations involving CRLs. To demonstrate the applicability and accuracy of the FrFT, the imaging resolution of a CRL‐based imaging system is estimated, and the FrFT approach is shown to be significantly more precise than comparable approaches using geometrical optics. Secondly, it is shown that extensive FrFT simulations of complex systems involving coherence and/or non‐monochromatic sources can be carried out in minutes. Specifically, the chromatic aberrations as a function of source bandwidth are estimated, and it is found that the geometric optics greatly overestimates the aberration for energy bandwidths of around 1%.     

The asymmetrical fractional Fourier transforms and its optical implement

Compared with the symmetrical lens system, the structure which contains double cylindrical lenses is also the basic units of a complex system and implement practical asymmetrical fractional Fourier transforms. Based on the theory of scalar diffraction and on the Fourier optics, we implement several kinds of asymmetrical fractional Fourier transforms and make the different mathematical manipulation at the corresponding coordinates, while the symmetrical system cannot. Meanwhile, the simulation experiment shows that such system not only makes the two perpendicular coordinates to be independently operated, but also increases the flexibility of the optical setup. All these characteristics make it flexible to application domain in optics.     

Study on the design and Zernike aberrations of a segmented mirror telescope

The segmented mirror telescope is widely used. The aberrations of segmented mirror systems are different from single mirror systems. This paper uses the Fourier optics theory to analyse the Zernike aberrations of segmented mirror systems. It concludes that the Zernike aberrations of segmented mirror systems obey the linearity theorem. The design of a segmented space telescope and segmented schemes are discussed, and its optical model is constructed. The computer simulation experiment is performed with this optical model to verify the suppositions. The experimental results confirm the correctness of the model.     

Pixellation of optically bistable elements

The elements of optical logic arrays can, in principle, be shielded from inter-element crosstalk by material pixellation. This confinement might seem to allow closer packing of such elements. However, using a Fourier optics approach to diffusion, we show that the pixellation process itself prevents radial removal of heat, and this can seriously affect device operation. The importance of this effect is illustrated by means of a numerical simulation.     

光致变色多阶光存储中的光学串扰分析

利用光致变色材料的灰度分阶特性可以实现多阶光存储。以傅里叶光学和光致变色记录符的可叠加性为基础,采用霍普金斯标量衍射理论的经典归-化坐标,对光致变色多阶光存储中的光学串扰进行了理论建模和数值分析。作为后续电通道补偿设计的前提。数值计算结果表明：相邻记录符与盘基信号的交叉串扰项是光学串扰的主要成分,且随着中心距的增加,相邻记录符引起的串扰迅速降低;当无寻道误差时,邻道记录符引起的串扰可以忽略;高阶记录符引起串扰要明显高于低阶的串扰。且影响多阶存储的可分阶性;实验结果很好地验证了所建立的模型的合理性。     

用于频域光学相干层析成像的深度分辨色散补偿方法

提出一种深度分辨的色散补偿方法,用于增强频域光学相干层析成像的纵向分辨率。将频域光学相干层析成像采集的干涉谱信号傅里叶变换到空域,获取对应不同深度的干涉谱条纹相位,通过对其进行调整实现对被测样品不同深度处的色散的精确补偿。避免传统方法中采用统一色散系数进行色散补偿所带来的过补偿与欠补偿误差,可以有效消除色散引起的频域光学相干层析成像系统点扩展函数的展宽和扭曲。模拟和实验结果表明,基于深度分辨的色散补偿方法在样品的全深度探测范围内可以达到较佳的补偿效果,可有效提高光学相干层析成像系统的纵向分辨率。