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In this letter, the axial distribution of Gaussian beam limited by a hard-edged aperture is studied. We theoretically analyze the axial diffraction of Gaussian beam limited by a hard-edged aperture, and give the simpler formulas of the axial diffraction intensities of Gaussian beam in Fresnel diffraction field and Fraunhofer diffraction field. The corresponding numerical calculation of axial diffraction intensity distribution of Gaussian beam with different wave waist is provided and the evolution of the diffraction distribution with the wave waist of Gaussian beam is explained. As the especial cases of the truncated Gaussian beam,the Gaussian beam in free space and the parallel light limited by the aperture are discussed too, and the system parameters of the truncated Gaussian beam which can cause it to equal to these cases are given.The theoretical results conform to the numerical analysis. 相似文献
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Transparent conducting ZnO:AI thin films with good adhesion and Iow resistivity have been prepared on organic substrates and Coming 7059 glass substrates by r.f. magnetron-sputtering technique at Iow substrate temperature (25-210℃). Structural and photoelectric properties of the deposited films are investigated. The deposited films are polycrystalline with hexagonal structure and a preferred orientation with the c-axis perpendicular to the substrate. Only the (002) peak is observed.High quality films with resistivity as Iow as 1.0 x 10- 3Ω@ cm and 8.4 x 10- 4Ω@ cm, the average transmittance over 74% and 85% in the wavelength range of the visible spectrum have been obtained on different substrates. 相似文献
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Intensity Distribution and Phase Vortices of Speckle Fields Generated by Multi-Aperture Random Scattering Screens 下载免费PDF全文
The intensity distribution and phase vortices of the speckle fields generated by multi-aperture random scattering screens are simulated, and it is found that the vortices exhibit layer-like structures and the dislocation phenomena occur in the local phase patterns produced by the two-pinhole aperture, whose phase distributions appear as striped structures. For three- or four-pinhole aperture, there are many circular bright spots appearing in the speckle grains, and there is one vortex between the neighboring circular bright spots. The positive and negative phase vortex lattices appear in the phase distributions, and the regions circled by the isothetic phase lines form irregular quadrilaterals or hexagons. Moreover, the relative positions of the vortices or bright spots can be adjusted by changing those of the pinhole apertures. 相似文献
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双剪切波面干涉测量法 总被引:7,自引:2,他引:5
用于星间通信的激光器具有接近衍射极限的激光波面,已有的波面测量方法,在这一具体测量问题中,都存在一定限制。双剪切波面干涉测量法在雅满横向剪切干涉仪的基础上,采用四块楔形平板,将干涉图分为上下两个部分,具有不同的条纹间距,由此求出波面高度和符号,同得到单幅干涉图的其它干涉测量方法相比,它的最小可测量波高减小一倍以上。在介绍干涉仪的基本结构和原理的基础上,模拟了像差存在时的干涉图,并在实验上得到了波高为0.3A的初步结果。双剪切波面干涉测量法,可以目视判断波差的符号和估计量值,为等光程相干,适用于半导体等相干长度小的光源。 相似文献
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In this letter, the axial distribution of Gaussian beam limited by a hard-edged aperture is studied. We theoretically analyze the axial diffraction of Gaussian beam limited by a hard-edged aperture, and give the simpler formulas of the axial diffraction intensities of Gaussian beam in Fresnel diffraction field and Fraun-hofer diffraction field. The corresponding numerical calculation of axial diffraction intensity distribution of Gaussian beam with different wave waist is provided and the evolution of the diffraction distribution with the wave waist of Gaussian beam is explained. As the especial cases of the truncated Gaussian beam, the Gaussian beam in free space and the parallel light limited by the aperture are discussed too, and the system parameters of the truncated Gaussian beam which can cause it to equal to these cases are given. The theoretical results conform to the numerical analysis. 相似文献
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在对4f光学成像系统中强散射体形成的像面散斑的统计特性的研究中, 首先通过散斑场光波复振幅的一般形式和双重指数函数近似求出散斑光强的系综平均, 然后利用散斑场光波复振幅的实部和虚部的旋转变换法求出散斑光强的方差, 最后得出了散斑对比度与随机表面统计参量和系统参量的直接表达式. 本结果与现有文献中包含随机表面相关面积或散射粒子数目的隐含表达式相比具有明显的改进, 并对标定随机表面的散斑对比度法具有重要意义.
关键词:
随机表面
像面散斑
对比度 相似文献