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Proceedings Paper

Intensity Distribution Transformation For General Beam-Shaping
Author(s): F. S. Roux; E. van Rooyen
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Paper Abstract

Holography and optical processing often require coherent input beams with intensity distributions which are different from the usual Gaussian distribution of a laser. Aspherical lenses are used to perform general beam-shaping in order to obtain the required intensity distributions. Computer generated holograms [CGHs] can also be used for beam-shaping. The calculation of these CGHs consist of two steps. First the required transformation equations, which will transform the available intensity distribution into the required intensity distribution, are derived from the two known intensity distributions with the aid of an integral equation. Then these transformation equations are substituted into differential equations from which phase functions are determined which are then encoded as CGHs. Two CGHs are required to perform the transformation. The first one diffracts the light to form the required intensity distribution a distance away. At that position the second CGH is placed to cancel the diffraction in order to retain the new intensity distribution. The resulting intensity distribution remains stationary from then on. This method has been implemented in terms of software. Various CGHs have been produced with the aid of this software. General intensity distributions are produced with these CGHs and the results are presented in this paper.

Paper Details

Date Published: 6 May 1989
PDF: 6 pages
Proc. SPIE 1052, Holographic Optics: Optically and Computer Generated, (6 May 1989); doi: 10.1117/12.951508
Show Author Affiliations
F. S. Roux, University of Pretoria (South Africa)
E. van Rooyen, University of Pretoria (South Africa)

Published in SPIE Proceedings Vol. 1052:
Holographic Optics: Optically and Computer Generated
Ivan Cindrich; Sing H. Lee, Editor(s)

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