Approximating Beam Diffraction by a Half-Plane

Abstract

For beam diffraction by a half plane it is shown that, provided the arguments of the Fresnel integrals are sufficiently large and the beam axis is directed at the half plane edge, the diffracted far field is exactly proportional to the isotropic source diffracted field modified by the ratio of beam to isotropic source fields at the edge. Thus the beam diffraction pattern can be easily calculated from Fresnel integrals with real arguments. The accuracy of this approach is illustrated by comparison with the exact solution in a numerical example. Approximating beam diffraction patterns of other structures this way is suggested.

Wide-angle diffraction of the laser beam by a sharp edge

“…With increasing distance from the screen, the frequency and the number of these oscillations decrease, so that the resulting field in the zone of Fraunhofer diffraction is completely free of such oscillations. Since the discussed evolution of the central part of this distribution is described and studied in detail in [3][4][5][6][7][8], we omit its detailed consideration and proceed to the main issue, namely, the wide-angle component of the diffracted radiation.…”

“…However, information on the above-described wide-angle component is absent in those works. The general structure of the field formed as a result of diffraction of a three-dimensional Gaussian beam was studied approximately in [7,8] and rigorously in [9,10]. However, such features as the phase structure of the field and, moreover, the detailed field structure in the far zone remained outside the scope of those papers.…”

Beam diffraction by a resistive half-plane

“…Recent studies on laser beam diffraction include 3D analysis, performed by the superposition of the diffracted waves by plane waves [12], and an experimental analysis of the scattering of a Gaussian beam by the edges of a plate [13]. Intensive study on the beam scattering by perfectly conducting half-planes and wedges was performed by Suedan and Jull [14][15][16][17]. They computed the diffracted beam fields by using the complex point source method with the far-field approximation.…”