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Proceedings Paper

Spatial superpositions of Gaussian beams
Author(s): Darryl Naidoo; Thomas Godin; Michael Fromager; Kamel Aϊt-Ameur; Andrew Forbes
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Paper Abstract

We explore an interferometric beam shaping technique that considers the coaxial superposition of two Gaussian beams. This technique is traditionally implemented in a Mach-Zehnder interferometer; however, to avoid phase shift drift due to vibrations and thermal effects we employ amplitude and phase modulation with a spatial light modulator (SLM) to achieve the beam shaping. We consider two Gaussian beams of equal but opposite curvature that possess the same phase and width incident on a focusing lens. At the plane of the lens we obtain a multi-ringed beam with a central intensity maximum which develops into a multi-ringed beam with a central null at the focal plane of the lens. The interesting feature of this beam is that it possesses two focal spots on either side of the focal plane of the lens. We investigate obstructing the beam at the focal plane of the lens and by carefully selecting the free parameters we obtain an unobstructed second focus while the equivalent Gaussian beam is sufficiently obstructed.

Paper Details

Date Published: 25 February 2014
PDF: 7 pages
Proc. SPIE 8999, Complex Light and Optical Forces VIII, 89991J (25 February 2014); doi: 10.1117/12.2039033
Show Author Affiliations
Darryl Naidoo, CSIR National Laser Ctr. (South Africa)
Univ. of Stellenbosch (South Africa)
Thomas Godin, FEMTO-ST (France)
Michael Fromager, Ecole Nationale Supérieure d'Ingenieurs de Caen (ENSICAEN) (France)
Kamel Aϊt-Ameur, CIMAP-ENSICAEN (France)
Andrew Forbes, CSIR National Laser Ctr. (South Africa)
Univ. of Stellenbosch (South Africa)


Published in SPIE Proceedings Vol. 8999:
Complex Light and Optical Forces VIII
David L. Andrews; Enrique J. Galvez; Jesper Glückstad, Editor(s)

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