Topic
Fresnel zone
About: Fresnel zone is a research topic. Over the lifetime, 2337 publications have been published within this topic receiving 37650 citations.
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TL;DR: In this article, the Fresnel diffraction pattern by a circular opaque disk under ultrashort pulsed-laser illumination is found to be significantly different from that under continuous wave (CW) illumination in the region of large Fresnel numbers.
8 citations
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20 Apr 1995
TL;DR: In this paper, a method for uniform top-hat intensity focal spot profiles obtained from Fresnel binary phase zone plate (PZP) arrays of various designs is presented. But, the intensity envelopes have in general been of a sinc form rather than ''top-hat''.
Abstract: Binary-phase optics have been used by a number of high-power laser laboratories in order to achieve relatively smooth focal spots. However, the intensity envelopes have in general been of a sinc form rather than `top-hat.' This paper presents work on the production of uniform `top-hat' intensity focal spot profiles obtained from Fresnel binary phase zone plate (PZP) arrays of various designs. Phase plates are used to generate large area smooth focal spots and both theoretical and experimental focal spots are presented. These demonstrate the flexibility of this technique which provides a simple method of generating both uniform `top-hat' intensity profiles and spatially shaped foci, for use with high-power lasers.
8 citations
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TL;DR: In this article, a method of calculating the radial intensity distribution of the Fresnel diffraction pattern of a circular aperture is presented. But this method can also be applied to calculations of more complicated apertures.
Abstract: The author presents a method of calculating the radial intensity distribution of the Fresnel diffraction pattern of a circular aperture. The method uses the concept of counting whole or partial Fresnel zones and has an accuracy of about five per cent of the maximum intensity, although it can be refined to improve this figure somewhat. The method can also be applied to calculations of the Fresnel diffraction patterns of more complicated apertures.
8 citations
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8 citations
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TL;DR: In this paper, the Rayleigh-Sommerfeld and Kirchhoff solutions to the diffraction of a converging spherical (or cylindrical) wave are expressed in terms of a series of derivatives of the field estimate that follows from the Fresnel approximation.
Abstract: By extension of the transitional operator method developed by Wunsche, the Rayleigh–Sommerfeld and Kirchhoff solutions to the diffraction of a converging spherical (or cylindrical) wave are expressed in terms of a series of derivatives of the field estimate that follows from the Fresnel approximation. This result allows a systematic assessment of the error associated with the paraxial wave model for focused fields and offers simple corrections to this model. In particular, for simple diffracting masks, the Fresnel approximation leads to estimates of the field that have a relative error near focus that is of the order of one on the square of the f-number. The number of significant digits in the field estimate is shown to be doubled by retaining just the first of the series of corrections derived here.
8 citations