Topic
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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TL;DR: In this paper, the Ewald-Oseen extinction theorem was used to obtain the depolarization of the electromagnetic wave from perfectly conductive slightly rough random surfaces, which is known to exist even in the backscattering and specular directions.
Abstract: The scattering and depolarization of electromagnetic waves from perfectly conductive slightly rough random surfaces is studied using the small perturbation method through the Ewald–Oseen extinction theorem. This permits predictions in those cases in which the physical optics, or the Kirchhoff approximation, fails, namely, at grazing incidence and when the wavelength of the incident radiation is comparable with the correlation length of the random heights. In this way it is seen, for example, that, as with the Rayleigh–Fano method, the depolarization of the fields is obtained from the second order of the expansion and exists even in the backscattering and specular directions. Also, unlike the predictions of the Kirchhoff approximation, this depolarization depends on the surface shape. However, this approach yields in the specular direction the same result as the Kirchhoff approximation for those cases in which the latter is known to be valid, i.e., for large correlation lengths and non-grazing-incidence directions and establishes precise conditions under which the Kirchhoff approximation is retrieved in the backscattering direction.
91 citations
01 Feb 2007
TL;DR: A brief history of spectroscopy can be found in this article, where the relevant regions of the electromagnetic spectrum are discussed and a brief review of spectrograph design and construction is given.
Abstract: 1. A brief history of spectroscopy 2. The relevant regions of the electromagnetic spectrum 3. Geometrical optics 4. Optical aberrations 5. Fourier transforms - a brief revision 6. Physical optics and diffraction 7. The prism spectrograph 8. The plane grating spectrograph 9. The concave grating spectrograph 10. The interference spectrograph 11. The multiplex spectrometer 12. Detectors 13. Auxiliary optics 14. Optical design 15. Mechanical design and construction 16. Calibration 17. The alignment of a spectrograph Index.
90 citations
TL;DR: In this article, a geometrical model using flat plates (panels) is described, and an ideal conducting cube with additional surfaces that generate shadow and double-reflection effects is compared with measurements.
Abstract: The backscatter computation of complicated objects is carried by the physical optics (PO) method, known as the vector Kirchoff approximation. The object is described by a geometrical model using flat plates (panels). These panels can be nonperfectly conducting and multilayered. The PO solution for the scattering matrix of a single multilayered panel is evaluated in detail using the Fresnel reflection coefficients. An example of the computed reflection coefficient of a two-layered medium is presented. The phase integral of the PO method is solved analytically. The hidden-surface problem is discussed, and the procedure for the treatment of doubly reflecting panels is described. For an ideal conducting cube with additional surfaces that generate shadow and double-reflection effects, the computed radar cross section (RCS) is compared with measurements. Computational results of the RCS for nonperfectly conducting panels are given. >
89 citations
TL;DR: An application of the semiclassical theory for propagation of an optical wave packet in a nonconducting medium with a periodic structure of dielectric permittivity and magnetic permeability to a two-dimensional photonic crystal is shown, and an optimal design for the enhancement of the optical Hall effect in photonic crystals is proposed.
Abstract: We construct a semiclassical theory for propagation of an optical wave packet in a nonconducting medium with a periodic structure of dielectric permittivity and magnetic permeability, i.e., a nonconducting photonic crystal. We employ a quantum-mechanical formalism in order to clarify its link to those of electronic systems. It involves the geometrical phase, i.e., Berry's phase, in a natural way, and describes an interplay between orbital motion and internal rotation. Based on the above theory, we discuss the geometrical aspects of the optical Hall effect. We also consider a reduction of the theory to a system without periodic structure and apply it to the transverse shift of an optical beam at an interface reflection or refraction. For a generic incident beam with an arbitrary polarization, an identical result for the transverse shift of each reflected or transmitted beam is given by the following different approaches: (i) analytic evaluation of wave-packet dynamics, (ii) total angular momentum (TAM) conservation for individual photons, and (iii) numerical simulation of wave-packet dynamics. It is consistent with a result by classical electrodynamics. This means that the TAM conservation for individual photons is already taken into account in wave optics, i.e., classical electrodynamics. Finally, we show an application of our theory to a two-dimensional photonic crystal, and propose an optimal design for the enhancement of the optical Hall effect in photonic crystals.
89 citations