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Physical optics

About: Physical optics is a research topic. Over the lifetime, 5342 publications have been published within this topic receiving 101388 citations. The topic is also known as: wave optics.


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Journal ArticleDOI
01 Aug 1965
TL;DR: In this article, two approximate methods have been developed for calculating the radar cross sections of nonconducting bodies, which can be applied to some bodies with shapes that cannot be treated by means of the classical boundary-value solutions.
Abstract: Two approximate methods have been developed for calculating the radar cross sections of nonconducting bodies. The superposition approximation used to obtain the radar cross sections of dielectric clad bodies requires that the scattering properties of the component parts be known. The modified geometrical optics method, which yields the radar cross sections of dielectric bodies, requires no such initial information. These methods can be applied to some bodies with shapes that cannot be treated by means of the classical boundary-value solutions. Furthermore, the computations required are usually considerably simpler than for the boundary-value solutions even when the latter are obtainable.

21 citations

Journal ArticleDOI
TL;DR: In this paper, the authors presented a concise analytic expression for the loss of all weakly attenuating rays on circular optical fibres, and provided a unifying theory of light transmission within fibres.
Abstract: Many of the rays on circular optical fibres that are predicted from geometric optics to be trapped by total internal reflection are, in fact, leaky Thus geometric optics fails for long fibres The letter presents a concise analytic expression for the loss of all weakly attenuating rays The method is simple, and applicable to a large class of problems The results provide a unifying theory of light transmission within fibres, representing a generalisation of Fresnel's and Snell's laws

21 citations

Journal ArticleDOI
TL;DR: Two led approaches take into account the specific geometrical properties of the considered surfaces to calculate their RCS and reduce the computing time with respect to the numerical PO technique, which requires two numerical integrations.
Abstract: The objective of this paper is to develop innovative approaches to obtain analytical expressions of the radar cross section (RCS) of perfectly conducting random rough surfaces under the physical optics (PO) approximation. The led approaches take into account the specific geometrical properties of the considered surfaces to calculate their RCS. The objective is to reduce the computing time with respect to the numerical PO technique, which requires two numerical integrations. All developed approaches are validated by comparison with a commercial code (the multilevel fast multi-pole method (MLFMM) of FEKO), used as a reference, and with measurements performed on three selected rough surfaces samples.

21 citations

Journal Article
TL;DR: In this paper, the authors make the nonlinear geometrical optics for wave trains with such a continuous oscillatory spectrum, which requires the introduction of new spaces, which are Wiener algebras associated to spaces of vector-valued measures with bounded total variation.
Abstract: The frequency and the direction of propagation of an oscillatory wave train may be read on its oscillatory spectrum. Many works in geometrical optics allow the study of at most countable oscillatory spectra. In these works, the number of directions of propagation is therefore at most countable, while many physical effects would require a continuous infinity of directions of propagation. The goal of this paper is to make the nonlinear geometrical optics for wave trains with such a continuous oscillatory spectrum. This requires the introduction of new spaces, which are Wiener algebras associated to spaces of vector-valued measures with bounded total variation. We also make qualitative studies on the properties of wave trains with continuous oscillatory spectrum, and on the incidence of the nonlinearity on such oscillations. We finally suggest an application of the results of this paper to the study of both the spontaneous and the stimulated Raman scatterings.

21 citations

Journal ArticleDOI
TL;DR: In this paper, the authors define the typical holographic reconstruction algorithm as the application of the scalar Kirchhoff diffraction theory to backward wave propagation, and demonstrate its general incapability of reconstructing equivalent sources, and hence, geometries of scattering bodies.
Abstract: For the purpose of ultrasonic nondestructive testing of materials, holography in connection with digital reconstruction algorithms has been proposed as a modern tool to extract crack sizes from ultrasonic scattering data. Defining the typical holographic reconstruction algorithm as the application of the scalar Kirchhoff diffraction theory to backward wave propagation, we demonstrate its general incapability of reconstructing equivalent sources, and hence, geometries of scattering bodies. Only the special case of a planar measurement recording surface, that is to say, a hologram plane, and a planar crack with perfectly rigid boundary conditions parallel to the hologram plane and perpendicular to the incident field yields a nearly perfect correlation between crack size and reconstructed image; the reconstruction algorithm is then referred to as the Rayleigh-Sommerfeld formula; it therefore represents the optimal case matched to that special geometrical situation and, hence, may be interpreted as a quasi-matched spatial filter. Using integral equation theory and physical optics, we compute synthetic holographic data for a linear cracklike scatterer for both plane and spherical wave incidence, the latter case simulating a synthetic aperture impulse echo situation, thus illustrating how the Rayleigh-Sommerfeld algorithm or its Fresnel approximation increasingly fail for cracks inclined to the hologram plane and excited nonperpendicularly. Furthermore, we point out how the physical data recording process may additionally influence the reconstruction accuracy, and, finally, guidelines for a careful and serious application of these holographic reconstruction algorithms are given. The theoretical results are supported by measurements.

21 citations


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Performance
Metrics
No. of papers in the topic in previous years
YearPapers
202357
2022157
202196
2020140
2019141
2018162