نتایج جستجو برای: fresnel diffraction

تعداد نتایج: 66847  

2014
Pin Han

The surface plasmon effects on near-field diffraction for polychromatic light are studied. An Au-double-slit is used as the model and Fresnel integral is employed to perform the theoretic analysis. The results are illustrated with numerical examples and they show that, compared with the normal double-slit, the plasmon effect changes the spectral shift from redshift to blueshift and also enhance...

Journal: :Optics express 1998
K Banaszek K Wodkiewicz W P Schleich

A phase space description of the fractional Talbot effect, occurring in a one--dimensional Fresnel diffraction from a periodic grating, is presented. Using the phase space formalism a compact summation formula for the Wigner function at rational multiples of the Talbot distance is derived. The summation formula shows that the fractional Talbot image in the phase space is generated by a finite s...

2001
A. V. Smirnov D. Yu

Abstract Fresnel diffraction dominated fields propagating at glancing angles in a wide planar and rectangular optical waveguides are considered. Both schemes are characterized numerically with multi-harmonic interaction. Resonant effect in terms of the energy gain versus geometry parameter is demonstrated. It is found that adjacent harmonics play a dominant role in the performance at short wave...

Journal: :Applied optics 2001
M Martínez-Corral L Muñoz-Escrivá A Pons

The scalar field in the focal volume of nontelecentric apodized focusing systems cannot be accurately described by the Debye integral representation. By use of the Fresnel-Kirchhoff diffraction formula it is found that, if the aperture stop is axially displaced, the focal-volume structure is tuned. We analyze the influence of the apodizing function and find that, whereas axially superresolving ...

2008
A. Gatti D. Magatti

We provide a detailed analysis of the three-dimensional spatial coherence properties of light speckles, based on very general assumptions. We show that, while in the deep Fresnel region close to the source the longitudinal coherence of speckles is ruled by the laws of ordinary diffraction, on approach to the Fraunhofer zone the longitudinal coherence length tends to become infinite. We offer bo...

Journal: :Applied optics 1996
J García D Mas R G Dorsch

A method for the calculation of the fractional Fourier transform (FRT) by means of the fast Fourier transform (FFT) algorithm is presented. The process involves mainly two FFT's in cascade; thus the process has the same complexity as this algorithm. The method is valid for fractional orders varying from -1 to 1. Scaling factors for the FRT and Fresnel diffraction when calculated through the FFT...

Journal: :Journal of the Optical Society of America. A, Optics, image science, and vision 2009
Hiroyuki Ichikawa Koji Masuda Takeshi Ueda

We report on a numerical analysis method for diffractive optical elements that consist of features ranging from subwavelength to more than 10lambda. The essence of the method is treating local structures of the optical elements as diffraction gratings. It is shown that the method can provide accuracy of results comparable with fully electromagnetic treatments in much shorter time. The theory an...

Journal: :Applied optics 2014
X Q Wang F Fan T Du A M W Tam Y Ma A K Srivastava V G Chigrinov H S Kwok

In this article, we disclose a method to fabricate a liquid crystal (LC) Fresnel zone lens (FZL) with high efficiency. The LCFZL, based on patterned planar-aligned regions, has been prepared by means of a two-step photoalignment technique. The proposed binary-phase LCFZL manifests 39% diffraction efficiency at the focal point, which is close to the theoretical limit, 41%. Moreover, because of a...

Journal: :Optics express 2012
Xiaojing Huang Michael Wojcik Nicolas Burdet Isaac Peterson Graeme R Morrison David J Vine Daniel Legnini Ross Harder Yong S Chu Ian K Robinson

A scanning coherent diffraction imaging method was used to reconstruct the X-ray wavefronts produced by a Fresnel zone plate (FZP) and by Kirkpatrick-Baez (KB) focusing mirrors. The ptychographical measurement was conducted repeatedly by placing a lithographed test sample at different defocused planes. The wavefronts, recovered by phase-retrieval at well-separated planes, show good consistency ...

2004
David Abookasis Joseph Rosen

We describe new techniques of synthesizing three types of computer-generated hologram (CGH); Fourier, Fresnel and image CGHs. These holograms, aimed to reconstruct three-dimensional (3-D) objects, are synthesized by means of a unique algorithm of fusing multiple perspective views of the observed scene. The hologram is initially generated in the computer as a Fourier hologram. Then, it can be co...

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