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Proceedings Paper

Effect Of Apertures On Gaussian Beams
Author(s): D. Allan Roberts; Robert J. Brown
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Paper Abstract

The theory of Gaussian beam propagation assumes a perfect, infinitely wide beam profile. In real life, when such beams pass through limiting apertures such as lenses, the profile is truncated. Even tiny amounts of truncation can have profound effects on subsequent beam parameters: clipping as little as one percent of the beam power, for example, can result in a ten percent divergence increase. Dark rings are created, and defocussing can create patterns with dark centers. For small truncation ratios (aperture/beam radius), the aperture is almost uniform and the focussed output approaches the traditional Airy disc pattern. In this paper, we will present a summary of the various truncation effects, with special attention to the most common case of a round aperture centered on a circularly symmetric beam. A computer program, based on one written at NASA, was used to generate plots of divergence versus truncation ratio for this case. Also discussed briefly are some of the possible deviations from circular symmetry: square beams and apertures, knife-edge obstructions, decentered apertures, and aberrations. Finally, the results reported by others have been summarized, with an extensive bibliography.

Paper Details

Date Published: 1 January 1987
PDF: 8 pages
Proc. SPIE 0818, Current Developments in Optical Engineering II, (1 January 1987); doi: 10.1117/12.978571
Show Author Affiliations
D. Allan Roberts, Ford Aerospace and Communications Corp. (United States)
Robert J. Brown, Ford Aerospace and Communications Corp. (United States)

Published in SPIE Proceedings Vol. 0818:
Current Developments in Optical Engineering II
Robert E. Fischer; Warren J. Smith, Editor(s)

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