共查询到20条相似文献,搜索用时 46 毫秒
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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
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We study a cosmological implication of holographic dark energy in the Brans–Dicke gravity. We employ the holographic model of dark energy to obtain the equation of state for the holographic energy density in non-flat (closed) universe enclosed by the event horizon measured from the sphere of horizon named L. Our analysis shows that one can obtain the phantom crossing scenario if the model parameter α (of order unity) is tuned accordingly. Moreover, this behavior is achieved by treating the Brans–Dicke scalar field as a Chameleon scalar field and taking a non-minimal coupling of the scalar field with matter. Hence one can generate phantom-like equation of state from a holographic dark energy model in non-flat universe in the Brans–Dicke cosmology framework. 相似文献
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发展具有大轴向定位范围的单分子定位技术对于实现厚样品的超分辨成像具有重要的价值.基于波前编码技术,将变形多值纯相位光栅与双螺旋点扩散函数相位片相结合,提出一种可以通过空间光调制器实现的具有高衍射效率的新型全息相位片的设计方法.这种全息相位片可以将样品内多个层面的分子信息以双螺旋的形式成像在同一个探测面的不同位置,在无需扫描的情况下提高双螺旋点扩散函数工程的轴向定位范围和分辨率,解决活细胞内单分子定位和示踪技术中的大景深探测难题.数值模拟表明,设计的5×5全息相位片可以将样品内25个层面上的分子信息以双螺旋的形式成像在同一探测面上的不同位置,相邻两个层面的间隔为0.5μm,实现了轴向12μm的探测范围,证明了设计的可行性. 相似文献
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Günther Wernicke Larbi Bouamama Oliver Kruschke Nazif Demoli Hartmut Gruber Sven Krüger 《Optics and Lasers in Engineering》2001,36(5)
Holographic microscopy with conjugate reconstruction for the interferometric determination of three-dimensional displacement was used for the investigation of the mechanical behaviour of micromechanic and microelectronic components. An experimental set-up for the exposure of the holographic interferograms is described for the application of the spatial heterodyne technique, for the application of phase shifting, and for electro-optic holography. Three holograms for different illumination directions recorded on one holographic plate were reconstructed conjugately, and spatial-heterodyne technique as well as phase-shift technique were used to evaluate the interferograms. Only by conjugated reconstruction, it is possible to obtain a perfectly optimised interferometer for the static evaluation method. The evaluation of interferograms, which are strongly disturbed by speckle noise, can be performed successfully. A comparison of the results of the application of these techniques is given. The influence of the speckle effect on the resolution was investigated. 相似文献
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F. Mendoza Santoyo G. Pedrini Ph. Frning H. J. Tiziani P. H. Kulla 《Optics and Lasers in Engineering》2000,32(6):18014-536
Pulsed digital holographic interferometry is a widely used technique for measurement of surface deformations. The results are displayed as high-quality images containing the surface deformation represented as a continuous function with high-precision and good resolution. On the theoretical side, the high precision finite-elements method (HPFEM) can be used to compute whole deformation maps of elastic continua, with a resolution comparable to that obtained with digital holographic interferometry. To prove the latter a series of resonant modes from a flat rectangular metal plate obtained with digital holographic interferometry will be compared to the same modes obtained under the same conditions with HPFEM. A very useful measurement concept is reached by combining both methods since they can be performed in parallel and within the same working area. 相似文献
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F. Dalmases R. Salvador M. Buendía C. Romero R. Cibrían J. L. Gandía 《Optics & Laser Technology》1988,20(5)
The use of a fringe-counting holographic interferometric technique for measuring small superficial displacements can present difficulties in determining the measurement inaccuracy. A useful general method is given here for the analysis of errors in displacement measurements. The optimum number and type of observation directions are determined and correspond to counting in the four semi-diagonals of the holographic plate. The technique, as applied to skull experiments, makes it possible to measure directly displacements of up to 20 μm, in the object plane parallel to the holographic plate. The associated errors range from 0.1–0.3 μm, for a counting inaccuracy of
of a fringe and increments of traction of 100 g to 1 kg of force. 相似文献
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Fabrication of Two-Dimensional Photonic Crystals with Triangular Rods by Single-Exposure Holographic Lithography 下载免费PDF全文
We demonstrate a single-exposure holographic fabrication of two-dimensional photonic crystal with round- cornered triangular 'atoms' arranged in a triangular lattice. Simulation results show that double absolute photonic band gaps exist in this structure. Our experimental results show that holographic lithography can be used to fabricate photonic crystals not only with various lattice structures but also with various kinds of structures of the atoms, to obtain absolute band gaps or a particular band gap structure. Furthermore, the single-exposure holographic method not only makes the fabrication process simple and convenient but also makes the structures of the atoms more perfect. 相似文献
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We present the study of angular selectivity for holographic multiplexing based on random phase encoding by a ground glass. The rotational selectivity of the volume hologram is calculated theoretically and coincides with the experimental measurement. By controlling the parameters including rotational center, effective numerical aperture of both volume hologram and the ground glass, we can obtain different rotational selectivity applied to random phase encoding in volume holographic storage. 相似文献
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Hassan Saadat 《International Journal of Theoretical Physics》2012,51(6):1932-1937
In this paper we consider holographic dark energy model with interaction in the flat space-time with non-zero cosmological
constant. We calculate cosmic scale factor and Hubble expansion parameter by using the time-dependent dark energy density.
Then, we obtain phenomenological interaction between holographic dark energy and matter. We fixed our solution by using the
observational data. 相似文献
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Localizing and Characterizing Colloidal Particles Scattering Using Lens-free Holographic Microscopy 下载免费PDF全文
Lens-free holographic microscopy could achieve both improved resolution and field of view(FOV), which has huge potential applications in biomedicine, fluid mechanics and soft matter physics. Unfortunately, due to the limited sensor pixel size, target objects could not be located to a satisfactory level. Recent studies have shown that electromagnetic scattering can be fitted to digital holograms to obtain the 3 D positions of isolated colloidal spheres with nanometer precision and millisecond temporal resolution. Here, we describe a lens-free holographic imaging technique that fits multi-sphere superposition scattering to digital holograms to obtain in situ particle position and model parameters: size and refractive index of colloidal spheres. We show that the proposed method can be utilized to analyze the location and character of colloidal particles under large FOV with high density. 相似文献
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Xu Wenxiao 《光学技术》1998,(1)
使用PVC、PET热塑全息膜,经过组合、高精度拼制及处理,电铸翻制成新的银版。可以用不同图案的全息模压膜任意组合成新图案,这是一种复制GGM的新方法。成本低,方法简单,有实际应用价值。 相似文献
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全息照相实验的新思路 总被引:3,自引:0,他引:3
在全息照相实验中,增加两种拍摄全息光栅的光路,在一张全息底片上,经过三次曝光,拍摄一幅全息图和两种光栅常量值的全息光栅,可使学生深刻地理解一张全息底片能够记录多个不同信息的原理。 相似文献
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A. Banijamali M. R. Setare B. Fazlpour 《International Journal of Theoretical Physics》2011,50(10):3275-3283
We construct a holographic dark energy density in the modified gravity for a non-flat space. We incorporate possible modification
of equation of state for the holographic energy density in the spirit of f(R) gravity. In this case we choose Jeans length as the IR cut-off in the holographic model. Then we employ the non-flat universe
for the holographic modified gravity to obtain a general form of f(R) in this setup. 相似文献
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调制光束全息干涉计量的研究 总被引:3,自引:0,他引:3
本文提出了干版运动对记录光束的调制作用及其对全息干涉计量的影响,推导了干版运动调制光束双曝光干涉图的光强分布的数学表达式.在对这种调制干涉条纹的理论研究基础上,提出了被测物体三维位移场的调制光束全息分析法.其中干版的运动用参考物体法确定. 相似文献
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Daniel S.F. Magalhães Rolando L. Serra André L. Vannucci Alfredo B. Moreno Li M. Li 《Optics & Laser Technology》2012,44(3):650-655
In this work we show two different glasses-free 3D viewing systems for medical imaging: a stereoscopic system that employs a vertically dispersive holographic screen (VDHS) and a multi-autostereoscopic system, both used to produce 3D MRI/CT images. We describe how to obtain a VDHS in holographic plates optimized for this application, with field of view of 7 cm to each eye and focal length of 25 cm, showing images done with the system. We also describe a multi-autostereoscopic system, presenting how it can generate 3D medical imaging from viewpoints of a MRI or CT image, showing results of a 3D angioresonance image. 相似文献