Showing papers on "Physical optics published in 1973"
TL;DR: In this paper, the edge currents derived from the edge diffraction theory for a halfplane were used to obtain the radiation patterns of a parabeloidal reflector antenna when illuminated by a source at the focus.
Abstract: Equivalent edge currents, derived from the edge diffraction theory for a half-plane, are used to obtain the radiation patterns of a parabeloidal reflector antenna when illuminated by a source at the focus. Cylindrical wave diffraction coefficients are used. The method avoids infinities at caustics and shadow boundaries thus giving solutions which are finite everywhere. A slope-wave equivalent current correction term is applied when the illumination is tapered towards the edge of the reflector. Comparisons are given with the physical optics approach and experimental results.
61 citations
TL;DR: In this article, the authors present a master equation for the reduced density operator (phase space distribution function) of the sub-system of interest, which is derived from the Fokker-Planck type.
Abstract: Publisher Summary This chapter focuses on master equation methods in quantum optics. Some of the methods have been specifically developed to treat the problems in quantum optics. These include the well known phase space methods. In phase space methods, the c-number distribution functions for quantum systems are introduced, which in many physical situations are found to obey equations of the Fokker–Planck type. In quantum optics, the concern is usually related to the study of a subsystem that is a part of a large system. Master equation methods have found applications in many branches of physics, such as in the theory of relaxation processes. The chapter also explains master equations for open systems. Some of the problems, involving open systems, in quantum optics are those of lasers, the relaxation of oscillators and two-level atoms, super-radiance, and parametric oscillators. In problems such as superradiance, the radiation field plays the role of the reservoir. The chapter describes the derivation of the master equation for the reduced density operator (phase space distribution function) of the sub-system of interest.
48 citations
TL;DR: A modification of the classical Rayleigh technique utilizing the fast Fourier transform (FFT) is developed for electromagnetic scattering and is referred to as the Rayleigh-FFT approach as discussed by the authors.
Abstract: A modification of the classical Rayleigh technique utilizing the fast Fourier transform (FFT) is developed for electromagnetic scattering and is referred to as the Rayleigh-FFT approach. Numerical scattering results from a sinusoidal surface are compared with calculations obtained by a Rayleigh perturbation approach, physical optics, and a rigorous integral equation method. These comparisons together with self-consistent error criteria are used to define the circumstances under which the Rayleigh-FFT approach is valid. For perfectly conducting sinusoidal surfaces, the method is valid at normal incidence when the maximum surface slope is less than about 0.6 ( \lsim 31\deg ) but no limit on surface height is apparent. Slope restrictions are explained by the inherent Rayleigh error since maximum errors occur in surface troughs as expected. The Rayleigh-FFT approach is increasingly reliable, for a given geometry, when the rough half-space tends toward dielectric from perfectly conducting. Perturbation solutions to Rayleigh's technique are shown to be extremely limited. Physical optics is valid when the minimum radius of curvature of the surface is greater than a wavelength. The Rayleigh-FFT method has been extended to obtain valid scattering results from arbitrary irregular periodic structures composed of a rough layer over a rough half-space.
31 citations
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
TL;DR: The autocorrelation function indicates a new method for determining the inner scale of turbulence and the refractive index structure function coefficient which does not depend upon meteorological measurements of C(N)(2).
Abstract: The log-intensity correlation for any two points in the cross section of a collimated Gaussian laser beam is calculated in the geometrical optics approximation. The log-intensity correlation is found to.be a function of more than the separation distance between the two points. The special case of autocorrelation leads to a result that is identical to that given by Ho if diffraction effects are ignored. The autocorrelation function indicates a new method for determining the inner scale of turbulence and the refractive index structure function coefficient which does not depend upon meteorological measurements of C(N)(2).
7 citations
TL;DR: The aberrations of four versions of interferometers with reflecting optics are discussed in this article, two of which have parabolic optics, one hyperbolic optics, and one a "thick" confocal system.
Abstract: Interferometers without refracting elements have the advantage of freedom from chromatic aberrations and absorption bands. The aberrations of four versions of interferometers with reflecting optics are discussed in this article, two of which have parabolic optics, one hyperbolic optics, and one a “thick” confocal system.
3 citations
TL;DR: In this paper, a hydrodynamic model is proposed to explain physically the behavior of Gaussian light-beam propagation in a medium whose refractive index varies slowly with position, and the expanding mechanism of the beam cross-section is interpreted as diffusion due to optical thermal pressure.
Abstract: A hydrodynamic model is proposed to explain physically the behaviour of Gaussian light-beam propagation in a medium whose refractive index varies slowly with position. The expanding mechanism of the beam cross-section, which cannot be explained by ray optics and wave optics, is well interpreted as diffusion due to ‘ optical thermal pressure ’, Justification of this model is also given.
01 Jan 1973
TL;DR: In this article, the utility of the physical optics approximation for the computation of electromagnetic fields of dipole sources in the neighborhood of conducting bodies of diverse shape in a lossy environment such as the ocean was explored.
Abstract: The utility of the physical optics approximation is explored for the computation of electromagnetic fields of dipole sources in the neighborhood of conducting bodies of diverse shape in a lossy environment such as the ocean. Excellent agreement with previous exact results is obtained for spheres down to one skin depth diameter with source-detector separation up to one skin depth. Only when the sphere size is reduced to one-tenth skin depth do errors in excess of three decibels begin to appear. Such comparisons have confirmed the accuracy of the method for application to non-spherical body shapes. The computer program allows investigation of the response for orthogonally oriented source and detection dipoles in the presence of smooth, curved, conducting bodies in a homogeneous lossy medium. Results are given for spheres, infinite cylinders, prolate spheroids and super-elliptic spheroids exposed to magnetic dipole sources.
01 Oct 1973
01 Jun 1973
TL;DR: In this paper, the authors deal with the geometrical optics as developed from Fermat?s principle of least time and focus on the tracking of ray and wave fronts through homogeneous and inhomogeneous media and throughout optical systems.
Abstract: This book deals with the geometrical optics as developed from Fermat?s principle of least time. It is concerned with the tracking of ray and wave fronts through homogeneous and inhomogeneous media and throughout optical systems. Among the many books that treat the subject of geometrical optics, most fail to prove, in the authors view, the concrete link with the underlying mathematical foundation on which geometrical optical technology has been erected. For this reason, the authors dwell in some detail on the mathematical background required for geometrical optics and on the optical interpretation and application of mathematical theorems.
01 Jan 1973
TL;DR: In this paper, the properties of the optical fiber have been described using the results of geometric optics, and these can also be described in the language of physical optics and, in certain instances, this approach is the only valid one.
Abstract: In previous chapters the properties of the optical fibre have been described using the results of geometric optics. However, these can also be described in the language of physical optics, and, in certain instances, this approach is the only valid one. In this respect, the optical fibre is no different from any other optical system.
01 Oct 1973
TL;DR: In this article, the mutual impedance between two identical MSA's is expressed as an integral over their power patterns including complex angles, and the secondary field pattern is calculated by a two-dimensional Romberg integration of the complex current distribution on the reflector found by the physical optics approximation and contour plots of gain and polarization loss are discussed.
Abstract: New results and conceptual design principles concerning multiple beam reflector antennas in which coupling effects are of major influence on antenna performance are presented. Special attention is paid to a certain class of feeds consisting of minimum scattering antennas (MSA's). The mutual impedance between two identical MSA's is expressed as an integral over their power patterns including complex angles [1]. For a given element spacing power patterns that minimize mutual coupling may be found. However, the patterns which lead to minimum coupling may not be optimum when the illumination of the reflector is considered. This is accounted for by constraining the efficiency for a given f/D-ratio. As an example of circularly polarized feed antennas detailed numerical analysis of coupling between arbitrarily oriented crossed dipoles is presented. In evaluating the scattered field from crossed dipoles the feeding network is included since a crossed dipole is never an MSA. The secondary field pattern is calculated by a two-dimensional Romberg-integration of the complex current distribution on the reflector found by the physical optics approximation and contour plots of gain and polarization loss are discussed. Also the scattered near field in the focal region is calculated in order to evaluate coupling between feed elements due to the presence of the reflector. Finally examples for coverage of specific areas on earth from a synchronous orbit satellite are presented.