Abstract

Gaussian beam propagation will show axial oscillations if the Gaussian beamwidth is comparable to the dimensions of the aperture. This effect is present whenever an optical element has a rectangular boundary, such as an aperture in a screen, a lens element, or a surface of a laser crystal. These oscillations are similar, but are not identical, to diffractions by circular apertures. Rectangular apertures could be characterized by an equivalent radius and an aspect ratio. Diffraction calculations on the severity of the axial oscillations will be presented. These axial oscillations are present over a specific range of the ratio of the Gaussian width to the equivalent radius of the aperture.

© 1990 Optical Society of America