Showing papers on "Physical optics published in 1969"
IBM1
TL;DR: The intensity and the degree of polarization of the radiation scattered by a large sphere were computed using the Mie theory at sufficiently small interval of the scattering angle for obtaining a complete picture of all the characteristics of the field of the scattered radiation.
Abstract: The intensity and the degree of polarization of the radiation scattered by a large sphere were computed using the Mie theory at sufficiently small interval of the scattering angle for obtaining a complete picture of all the characteristics of the field of the scattered radiation. The results are presented for four different sizes of the water sphere (radius = 6.25 micro, 12.5 ;micro, 25.0 micro, and 50.0 micro) assumed to be illuminated by an unpolarized beam of monochromatic radiation with wavelength 0.4 micro. A detailed comparison is then made between the results obtained using the exact Mie theory and those obtained using an approximate approach based on the application of the other laws of the geometrical and physical optics. The angular positions of the primary and secondary rainbows, as well as those of their supernumerary bows as obtained using the approximate method, agree with those obtained from the Mie theory only if the size parameter of the sphere is of the order of 800. Besides the phenomenon of glory which is not amenable to explanation in terms of the geometrical and physical optics, the Mie computations bring out several distinct maxima and minima whose occurrence cannot be explained in likewise manner.
86 citations
TL;DR: In this paper, an approximate solution to the problem of a light wave propagating through a lens is obtained by systematically replacing the integrals required to solve the problem by their stationary-phase approximation.
Abstract: An approximate solution to the problem of a light wave propagating through a lens is obtained by systematically replacing the integrals required to solve the problem by their stationary-phase approximation. This approach is shown to yield (1) geometrical optics in its eikonal form, and (2) a diffraction theory of image formation applicable to lenses with large apertures and fields.
27 citations
TL;DR: In this paper, an analysis theory of the shape-beam doubly curved reflector antenna is described, which utilizes a computer solution approach to achieve an accurate knowledge of the principal and cross-polarization elevation and azimuth patterns by numerically integrating the field contributions over the entire reflector surface.
Abstract: An analysis theory of the shaped-beam doubly curved reflector antenna is described. The analysis computes the far-field patterns by calculating the current density distribution on the nonanalytic surface that the shaped-beam doubly curved reflector presents using the physical optics vector approximation. The presented theory utilizes a computer solution approach to achieve an accurate knowledge of the principal and cross-polarization elevation and azimuth patterns by numerically integrating the field contributions over the entire reflector surface. A comparison of the computed and measured principal plane patterns is shown.
21 citations
TL;DR: In this paper, coupled amplitude equations are derived to describe the interaction of three light waves propagating in a nonlinear dielectric waveguide, and the coupling coefficients reflect the combined effect of the nonlinear susceptibility and the finite geometry.
Abstract: Coupled amplitude equations are derived to describe the interaction of three light waves propagating in a nonlinear dielectric waveguide. The coupling coefficients reflect the combined effect of the nonlinear susceptibility and the finite geometry.
15 citations
TL;DR: It is concluded that multiple scattering due to aerosols comprises the only mechanism of possible importance, and should be observable with shorter pulses or large angle optics, pertinent to recently proposed, sophisticated optical communications and radar techniques.
Abstract: The possible effects of the atmosphere on the propagation of short optical pulses are estimated, and experiments are described using real time pulse-comparison techniques over a 1.6-km path. With a pulse duration of 1.5 nsec, an optical thickness of 2.8, and a typical angular beamwidth and field of view, pulse distortion was not observed. It is concluded that multiple scattering due to aerosols comprises the only mechanism of possible importance, and should be observable with shorter pulses or large angle optics. The results are pertinent to recently proposed, sophisticated optical communications and radar techniques.
9 citations
01 Jan 1969
TL;DR: In this article, an analysis of the principal and cross-polarization elevation and azimuth patterns of a shape-beam doubly curved reflector antenna is presented.
Abstract: An analysis theory of the shaped-beam doubly curved reflector antenna is described. The analysis computes the far-field patterns by calculating the current density distribution on the non- analytic surface that the shaped-beam doubly curved reflector pre- sents using the physical optics vector approximation. The presented theory utilizes a computer solution approach to achieve an accurate knowledge of the principal and cross-polarization elevation and azimuth patterns by numerically integrating the field contributions over the entire reflector surface. A comparison of the computed and measured principal plane patterns is shown.
8 citations
TL;DR: In this paper, it was shown that the basic reason why Kerr's physical optics formula for the reflectivity of an axially viewed perfectly conducting body of revolution is also useful when the wavelength is not small compared to body dimensions is because the electric dipole and the magnetic dipole plus electric quadrupole are the dominant multipole sources for reflection.
Abstract: It is shown that the basic reason why Kerr's physical optics formula for the reflectivity of an axially viewed perfectly conducting body of revolution is also useful when the wavelength is not small compared to body dimensions is because the electric dipole and the magnetic dipole plus electric quadrupole are the dominant multipole sources for reflection.
5 citations
4 citations
TL;DR: Eckert shadow technique for radiation view factors applied to toroid inside shadow hemisphere as discussed by the authors was used to calculate the radiation view factor applied to the toroid's toroid inner shadow hemisphere.
Abstract: Eckert shadow technique for radiation view factors applied to toroid inside shadow hemisphere
01 Feb 1969
TL;DR: In this article, it is shown that the approximation of geometrical optics is violated close to those points where either the wave vector k(x) becomes zero (reversal point), or where the wave vectors corresponding to the different types of oscillation coincide (points of intersection of the solutions).
Abstract: It is a familiar fact that in the approximation of geometrical optics the normal oscillations in a weakly inhomogeneous medium are independent. The approximation of geometrical optics is, however, violated close to those points where either the wave vector k(x) becomes zero (reversal point), or where the wave vectors corresponding to the different types of oscillation coincide (points of intersection of the solutions). In the immediate neighborhood of these points separation into normal oscillations is no longer possible, which in the case of “points of intersection of the solutions” leads to the possible appearance, in addition to the wave incident from infinity, of another new wave with different dispersive properties.
01 Jan 1969