scispace - formally typeset
Search or ask a question
Topic

Fresnel zone

About: Fresnel zone is a research topic. Over the lifetime, 2337 publications have been published within this topic receiving 37650 citations.


Papers
More filters
Journal ArticleDOI
TL;DR: It is shown that, in the absence of third-order dispersion, the transmission of sequences of pulses of finite linewidth through monomode fibers is mathematically analogous to spatial Fresnel diffraction.
Abstract: The transmission of sequences of pulses of finite linewidth through monomode fibers is investigated using methods of optical coherence theory. It is shown that, in the absence of third-order dispersion, this is mathematically analogous to spatial Fresnel diffraction. The effect of optical interference of overlapping pulses on the transmission capacity is discussed.

9 citations

Journal ArticleDOI
TL;DR: In this article, it was shown that the normalized geometrical spreading factor is inversely proportional to the area of the first Fresnel zone associated with the reflection point, which represents the principal part of the wavefield obtained by Fresnel-Kirchhoff diffraction theory.
Abstract: Conventionally, the Fresnel zone and the geometrical spreading factor are investigated separately, because they belong to different theories of wave propagation. However, if the paraxial ray method is used for establishing the Fresnel–Kirchhoff diffraction formula for a laterally inhomogeneous multilayered medium, it can be shown that the normalized geometrical spreading factor is inversely proportional to the area of the first Fresnel zone associated with the reflection point. Therefore, if no diffracting edge cuts the first Fresnel zone, the geometrical optics approximation represents the principal part of the wavefield obtained by Fresnel–Kirchhoff diffraction theory. Otherwise, the geometrical optics approximation has to be corrected by adding edge diffractions. It is also shown that Kirchhoff-type migration and geometrical spreading factor correction both reduce the first Fresnel zone to a zone with unit area.

8 citations

Journal ArticleDOI
Jie Li1, Chaojie Yang1, Jiaming Li1, Ziwei Li1, Shuai Zu1, Siyu Song1, Huabo Zhao1, Feng Lin1, Xing Zhu1 
TL;DR: In this article, the surface plasmon focusing has been shown to achieve a sub-wavelength focusing effect with the focusing spot at a subwavelength scale, based on the principle of optical interference that the constructive superposition of SPs with phase matching can result in a considerable electric-field enhancement of SP in the near field.
Abstract: In this review, we show that by designing the metallic nanostructures, the surface plasmon (SP) focusing has been achieved, with the focusing spot at a subwavelength scale. The central idea is based on the principle of optical interference that the constructive superposition of SPs with phase matching can result in a considerable electric-field enhancement of SPs in the near field, exhibiting a pronounced focusing spot. We first reviewed several new designs for surface plasmon focusing by controlling the metallic geometry or incident light polarization: We made an in-plane plasmonic Fresnel zone plates, a counterpart in optics, which produces an obvious SP focusing effect; We also fabricated the symmetry broken nanocorrals which can provide the spatial phase difference for SPs, and then we propose another plasmon focusing approach by using semicircular nanoslits, which gives rise to the phase difference through changing refractive index of the medium in the nanoslits. Further, we showed that the spiral metallic nanostructure can be severed as plasmonic lens to control the plasmon focusing under a linearly polarized light with different angles.

8 citations

Journal ArticleDOI
TL;DR: In this article, the exact vector angular spectrum (VAS) was used to analyze the near-field focusing properties of actual hybrid amplitude-phase binary subwavelength Fresnel zone plates (HBSFZPs).
Abstract: The near-field focusing properties of actual hybrid amplitude–phase binary subwavelength Fresnel zone plates (HBSFZPs) are studied theoretically. The analysis based on the exact vector angular spectrum method is done for a radially polarized beam incident on the HBSFZPs. The results show that the near-field subwavelength focusing with a long depth of focus can be obtained using an HBSFZP, which is very useful for near-field subwavelength photolithography and high-resolution microscopy. The position of the actual focus in the near-field focusing HBSFZPs depends on the evanescent wave rather than the propagating wave. The etch depth has an important influence on focusing properties of HBSFZPs.

8 citations

Journal ArticleDOI
TL;DR: In this article, a new factorization method is described that establishes the geometrical spreading factor and the number of caustics recursively along the ray segments into which the total ray can be subdivided.
Abstract: The computation of the geometrical-spreading factor and the number of caustics is often considered to be the most fundamental step in computing zero-order ray solutions for elementary-wave Green`s functions along a ray that originates at a point source and passes through a 3-D laterally inhomogeneous isotropic medium. Here, a new factorization method is described that establishes both quantities recursively along the ray segments into which the total ray can be subdivided. As a consequence of the proposed method, the point-source geometrical-spreading factor and the number of ray caustics along the total ray can be decomposed into (1) point-source spreading factors of the ray segments and (2) certain Fresnel zone contributions at the ray-segment connection points. In a so-called ``3-D simple medium,`` by which any 3-D laterally inhomogeneous medium can be approximated, the new factorization approach permits a simple computation of both quantities. It thus simplifies and provides new insights into the computation of ray-theoretical Green`s functions.

8 citations


Network Information
Related Topics (5)
Resonator
76.5K papers, 1M citations
83% related
Wave propagation
55K papers, 1.1M citations
82% related
Polarization (waves)
65.3K papers, 984.7K citations
82% related
Optical fiber
167K papers, 1.8M citations
81% related
Diffraction
63.7K papers, 1M citations
79% related
Performance
Metrics
No. of papers in the topic in previous years
YearPapers
202326
202249
202137
202052
201965
201878