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荧光共焦扫描系统成像特性的优化 总被引:8,自引:0,他引:8
对荧光共焦扫描系统用光强点扩散函数进行傅里变换得到系统三维传递函数的数学模型,并由此求得环形透镜和各种有限大小探测器系统的光学传递函数。用计算机模拟和光学传递九数值计算,分析了采用不同环形透镜及探测器对系统成像特性的影响 相似文献
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本文描述了计算机控制环形染料激光器实现无间断自动扫描10THz的光学调谐元件设计、运转机制及实验结果。 相似文献
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基于全景环形透镜的成像技术是全景成像中的一种最具潜力的成像方式,具有高分辨率的长焦距全景环形透镜成像系统光学结构较复杂,结构设计是首要解决的问题.本文根据全景环形透镜成像系统的光路结构及成像特性,详细讨论了全景环形透镜和转像透镜组两部分的设计方法,分别设计了单块全景环形透镜和复杂化全景环形透镜,并对它们的像差特性做了对比,分析了它们之间的光路衔接条件和像差补偿方案.该设计采用小尺寸CCD离轴扫描接收环形像,同时分析了这种扫描机构的可行性.系统要求在300m处需分辨250mm大小的物体,通过计算合理地选择了系统焦距和CCD型号并制定了一套技术指标.最终设计出了焦距8mm,F/#3.2,侧向视场40°~100°的高分辨全景环形透镜成像系统,系统由三胶合结构的全景环形透镜和8片6组的转像透镜组构成,所有表面均为球面.该系统全视场的调制传递函数在80lp/mm处均高于0.5,最大视场像面的相对照度高于0.95,全视场f-θ畸变在±3%以内,该设计很好地满足了使用要求. 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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A simple experimental method of eliminating zero-order diffraction in the reconstructed image of off-axis digital holography is presented. Holographic diffraction grating acting as a beam splitter, an off-axis holography system is formed. The holograms of object with different recording parameters are obtained by adjusting the reflecting mirror in the recording optical system to vary the incidence orientation of the object beam in CCD to introduce a phase shift. The zero-order image can be eliminated by numerically processing the holograms of object with different recording parameters. The theoretical analyses have been done in detail and the experimental results are also given. The zero-order image eliminated, the area of reconstructed image increases remarkably, the image quality can then be significantly improved and the better resolution obtained. The experimental results show that the method presented in this paper is feasible, simple in optical system and easy in operation and data processing. 相似文献
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We consider the possibility of restoration and/or enhancement of decaying holograms in photorefractive media by using a simple optical readout in conjunction with a phase conjugator. The results indicate that extremely weak holograms can be enhanced provided that the two-beam coupling is sufficiently strong. Steady-state photorefractive holograms can be maintained continuously without decay by using a self-enhanced readout scheme. The results also provide an explanation for the formation of mutually pumped phase conjugation in terms of the amplification of an initial noise grating. The results are presented and discussed. 相似文献
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We demonstrate an innovative method for fabrication of high-spatial-frequency grating structures. This technique makes use of the near-field diffraction patterns from computer-generated phase holograms for lithographic fabrication of grating structures with periods that are one half that of the phase hologram mask. Linear, rectilinear, and circular gratings were fabricated with this technique. Experimental results from gratings with periods to 0.5 mum and feature sizes to ~0.2 mum are presented. 相似文献
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This paper explores the feasible use of circular optical grating for measuring the rotation of mirrors that are commonly found in micro-systems. Both theoretical and experimental results show that distortion of the circular grating that is projected onto the mirror surface is a simple function of the angular rotation of the mirror. The circular grating may readily be generated using a standard Michelson interferometer or an LCD projector. Through manipulating the distance between the interferometer and the mirror surface, the diameter of the optical grating may be varied. Furthermore, the additional use of a converging lens enables a significant reduction in the size of the grating: with simple laboratory facility, small circular grating of about 400 μm is achieved for use on micro-systems. With the use of more sophisticated optical elements, the angular rotation of even smaller micro-mirrors may be measured. 相似文献
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Dovol'nov E. A. Pen E. F. Sharangovich S. N. Shelkovnikov V. V. 《Russian Physics Journal》2004,47(7):773-783
The formation of holographic transmission gratings in absorbent photopolymer materials (PPM) is studied theoretically. Analytical model describing a spatiotemporal transformation of holographic grating field during record is developed with allowance for optical absorption and diffusion processes. It is demonstrated that optical attenuation during record causes the spatial inhomogeneity of refractive index grating profile and of the its growth kinetics. A degree of influence of optical attenuation on the integral diffraction characteristics is evaluated based on numerical simulation. The kinetics of record of high-efficient transmission holograms in PPM is experimentally investigated. Based on a comparison of theoretical and experimental time dependences of diffraction efficiency, physical parameters of the examined PPM are determined and adequacy and tendency in the development of the suggested mathematical model are evaluated. 相似文献
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Yongjin Wang Fangren Hu Masashi Wakui Kazuhiro Hane 《Applied Physics A: Materials Science & Processing》2009,97(1):39-43
We report here a top-down process for fabricating a freestanding circular GaN grating. The circular gratings are defined by
electron-beam lithography and realized by fast-atom beam (FAB) etching. The silicon substrate below the GaN grating region
is completely removed to make the circular grating suspended in space. The optical responses of the fabricated GaN gratings
are characterized in reflectance measurements. The polarization-independent responses of circular gratings are experimentally
demonstrated, corresponding well with the theoretical prediction. This work represents an important step in combining GaN-based
material with freestanding nanostructures. 相似文献
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Past research has demonstrated that hologram of a real world object can be acquired by scanning it with a single two-dimensional optical scan. The technology commonly referred to as optical scanning holography (OSH), have found important applications such as in microscopy, pattern recognition, 3D holographic display, and optical remote sensing. As holograms are often employed to capture three dimensional objects with high resolution, large amount of data is required to represent them. In this paper we propose a method for compressing holograms based on Delta modulation. Specifically, we apply our proposed method for holograms captured by OSH. Experimental evaluation reveals that our proposed approach is capable of attaining a compression ratio of 64 times, and still preserves favorable fidelity on the reconstructed images. In addition, both the encoding and decoding processes of the proposed method are very low in complexity, hence enabling real-time operation. 相似文献
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二步合成平板周视彩虹全息术 总被引:4,自引:0,他引:4
提出一种将物光波前先分解记录,再合成的二步平板周视彩虹全息术。波前的分解记录与合成彩虹全息图是分别通过转动物体和干板来实现的。记录这种周视全息图,不需要大孔径和其它特殊光学元件,即可获得周视半径大的无象差立体再现象。该方法可直接用于模压全息图母板的制作。 相似文献