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二维光栅光调制器阵列的光学分析与实验 总被引:5,自引:3,他引:2
基于标量衍射理论分析了二维光栅光调制器的衍射特性,提出了投影系统的光学处理方法,利用Matlab软件进行了仿真分析.分析结果表明,二维光栅光调制器的衍射光强分布是单个像素衍射光强的干涉叠加,其分布趋势与单个光调制器的衍射光强分布类似;通过反傅里叶变换可将各个调制器的衍射光重新分开而成像.如果用±1级衍射光的成像,相位为2kπ的调制器在投影面得到一个明亮的像,而相位为(2k-1)π的调制器在投影像面上得到一个黑暗的像.通过一个基于静态微光电系统光栅光调制器的投影光学系统得到了一幅明暗调制的像,证明了光栅光调制器用于投影显示的可行性. 相似文献
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凹面光栅型波长解复用器的标量波动分析 总被引:5,自引:1,他引:4
利用标量波动衍射理论,通过对光栅槽面的数值积分,计算了罗兰圆型集成二维凹面光栅像点的光强分布。给出了光线追变法难以得到的光栅槽面沿光栅圆不同方位刻划所引起的成像点对于光栅方程计算位置的偏离;在对色散和分辩力的分析上,获得了与光线追迹法很好的一致性;分析了光栅的槽面波、光源的模场宽度以及因工艺产生的槽面圆角对光栅成像的影响;最后给出了光栅的波像差和光线像差的计算。 相似文献
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提出和发展了一种基于大数值孔径环形光锥照明的远场超分辨光学显微成像新方法, 采用将发光二极管(LED)面光源、窄带滤光和环形光锥照明相结合的特种照明方式, 实现超分辨显微成像. 建立了大数值孔径环形光锥照明成像的物理模型, 根据标量衍射理论, 在不同环形光锥照明时, 推导出光学显微系统像面衍射斑光强分布的理论计算公式; 通过Matlab求解和绘图, 得到衍射斑光强的分布图样, 从理论上证明这一成像方法可以有效提高光学显微镜的分辨率; 建立了相应的显微成像系统, 通过实验验证了该方法可有效改善显微镜的成像质量, 显著提高分辨率; 在中心波长450 nm、环形光锥数值孔径1.125—1.25时, 实验获得的分辨率至少优于150 nm, 与理论研究结果相符合, 从而证明了这一方法的可行性. 相似文献
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卢进军杨凯孙雪平朱维兵吕华 《光学学报》2013,(11):54-59
为了分析Schmidt棱镜偏振像差在自然光成像系统中对成像质量的影响,以线偏振光矢量衍射光强分布为基础,利用两种非相干叠加积分模型,获得了自然光通过Schmidt棱镜后完全相同的衍射光强分布关系。通过这个关系式分析得知,自然光经过屋脊棱镜的偏振像差表现为衍射光斑的对称分裂。对分裂导致的像面中心亮度比、分辨率以及所提出的像面变形度等像质评价参数进行了分析计算。结果表明,Schmidt棱镜的成像质量受到其偏振像差的影响严重。Jones矩阵因子B作为棱镜的结构特性参数,影响并决定棱镜的成像质量。B因子的大小就是Schmidt棱镜偏振像差的大小。理论分析及实验结果均表明,B=0为校正Schmidt棱镜偏振像差的一个条件。 相似文献
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用相因子判断法分析条形余弦光栅衍射场 总被引:4,自引:0,他引:4
基于波前相因子判断法并考虑到光栅孔径的影响,揭示了余弦光栅的衍射场所含基元成分.给出了各基元成分衍射场的积分表达式,进而导出了像面上光强分布的公式,并显示了相应的沿轴线的光强分布曲线,得到各焦斑的半值线宽公式.本研究为余弦光栅用于空间滤波和光学信息处理技术提供了一个理论基础. 相似文献
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使用衍射光栅的分色分光方式一般以平行光入射情况为讨论基础,对于非平行光入射的情况讨论较少.本文基于菲涅尔衍射理论和角谱理论,将球面波与平面波的衍射波场联系起来,从而在传播函数中引入角度参量,结合分数泰伯效应的理论基础,推导出双波长宽角度入射光线经相位光栅衍射后的波场分布函数,并对推导出的函数进行数值模拟,得到像面不同位置衍射波场分布.与平行光入射时的标准波场分布相比较,得到宽角度入射时的衍射波场的横向展宽量和偏移量.通过调节光栅台阶的宽度,改变衍射场的展宽和偏移,使各个单一波长的衍射波场宽度小于光栅周期的一半,从而减少双波长光衍射波场的混叠.同时本文给出波场宽度与光栅台阶宽度的变化关系,选取光栅面上多个位置作为台阶宽度的计算点,并对整个光栅的台阶宽度进行曲线拟合,得到可以使双波长宽角度入射光实现良好空间分离的光栅参量.该结果可用于各类宽角度入射光线的光谱分离场合,如双波长成像、液晶显示和液晶投影等. 相似文献
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对光学设计中照度计算公式的讨论 总被引:6,自引:2,他引:4
分析并指出了教科书及光学软件中光学系统照度公式的不恰当地方,推导出了更符合实际的光学系统照度公式.假设透镜系统为无源传输模式,通过对教课书中以及光学设计软件中的照度分布计算公式进行了推导分析,得出轴外视场相对轴上视场照度为cos4 ω'关系.当像方视场角减小时,通过模拟得到了与实际相背的无源传输系统能量放大的结论.建立了以入瞳模式为参考的计箅模型,对照度公式重新进行推算得到新的与实际相符的照度公式,得出像面照度分布取决的是物方视场角.通过仿真模拟.验证了像面上轴外视场的照度与对应物方视场角的cos4 ω成止比. 相似文献
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We describe a new optoelectronic system for correcting aberrations of the objective lens with the help of an electron mirror. The system is based on the implementation of a special focusing regime (so-called regime of superimposed images) in which two images of the object are formed in the plane passing through the center of the curvature of the mirror. One of these images is formed by the beams (with aberrations) emerging from the objective lens, and the other is formed by the beams (with cancelled aberrations) reflected from the mirror. The separation of the two superimposed images and visualization of the image with cancelled aberrations are performed by deflection of the electron beam in the axisymmetric magnetic field whose symmetry axis passes through the center of curvature of the electron mirror. The magnetic field distribution ensuring aberration-free deflection of the electron beam is calculated. 相似文献
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在大截面传像束前置光学系统设计中,采用负-正型式的像方远心光路结构,在像差校正过程中引入偶次非球面和弯月形厚透镜,可较好地解决镜头轴外像差校正与像面照度均匀性问题,同时使镜头结构紧凑、小型化。通过理论计算和优化,给出工作在660 nm,焦距f=1.22 mm,相对孔径D/f=1∶3,视场角2为60的镜头设计实例。设计结果表明:该镜头各视场在40lp/mm空间频率处的MTF值超过0.8,全视场畸变小于0.05%,场曲低于50m,像面照度均匀,像质优良,满足像方远心光路要求,可用于实际观察和测量。 相似文献
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Design of the spatial filter window for digital holographic convolution reconstruction of object beam field 总被引:1,自引:0,他引:1
In the convolution reconstruction process of digital holographic object beam field, the object beam fields with different magnifications can be obtained when the reconstructing beams are spherical waves with different wave curvature radii. This paper presents a theoretical and experimental discussion on the useful spatial frequency spectrum of the hologram numerically illuminated by the spherical wave. The result shows that there would be an image in the spatial frequency spectrum of digital hologram, which is completely the same as the object, if the wave surface radius of the spherical wave is equal to the distance from the object to the CCD sensor. Taking this image as a reference and designing a filter, the position of the reconstructed images with different magnifications can be predicted correctly in the reconstructed plane. Additionally, since the spectrum distribution of zero-order diffraction can be forecasted accurately in theory, its contribution can be effectively eliminated through changing the spatial filter shape; then a reconstructed object field containing more high-frequency information can be obtained. 相似文献
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I. K. Kabardin V. G. Meledin I. A. Eliseev V. V. Rakhmanov 《Journal of Engineering Thermophysics》2011,20(4):407-415
An optical method of measuring the instantaneous transparent liquid film thickness, based on the effect of total internal
reflection by the gas-liquid interface, is represented. A light circle whose diameter is proportional to the liquid film thickness
and eccentricity is proportional to the slope gradient of the liquid film surface in the measurement region is formed around
a small-size light source in the plane of vessel bottom. Using several light sources, the method allows measurement of the
liquid film thickness field. The method is implemented in a multichannel meter of transparent liquid film thickness and curvature
surface, with computer image processing. 相似文献
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《Waves in Random and Complex Media》2013,23(3):364-384
A family of unified models in scattering from rough surfaces is based on local corrections of the tangent plane approximation through higher-order derivatives of the surface. We revisit these methods in a common framework when the correction is limited to the curvature, that is essentially the second-order derivative. The resulting expression is formally identical to the weighted curvature approximation, with several admissible kernels, however. For sea surfaces under the Gaussian assumption, we show that the weighted curvature approximation reduces to a universal and simple expression for the off-specular normalized radar cross-section (NRCS), regardless of the chosen kernel. The formula involves merely the sum of the NRCS in the classical Kirchhoff approximation and the NRCS in the small perturbation method, except that the Bragg kernel in the latter has to be replaced by the difference of a Bragg and a Kirchhoff kernel. This result is consistently compared with the resonant curvature approximation. Some numerical comparisons with the method of moments and other classical approximate methods are performed at various bands and sea states. For the copolarized components, the weighted curvature approximation is found numerically very close to the cut-off invariant two-scale model, while bringing substantial improvement to both the Kirchhoff and small-slope approximation. However, the model is unable to predict cross-polarization in the plane of incidence. The simplicity of the formulation opens new perspectives in sea state inversion from remote sensing data. 相似文献
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提出了一种研究口径辐射的新算法,它将已知的实口径面上的场分布解析开拓,求得一复口径面上的场分布,进而利用相应复口面的Kirchhoff褶积公式,间接但严格地表示出了原口面的辐射特性。就一线性相移口径作了数值计算,并与相应的标准解作了比较。 相似文献