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Proceedings Paper

Towards top-hat spatial shaping of ultrafast laser beam based on Zernike polynomials
Author(s): Cyril Mauclair; Nicolas Faure; Julien Houzet
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Paper Abstract

Femtosecond laser micro machining of surfaces knows a gain of interest as it demonstrates efficient and precise processing with reduced side effects around the irradiated zone, and also because of the remarkable costs reduction and reliability improvements of nowadays commercially available sources. Controlling the intensity distribution spatially can offer a supplementary degree of flexibility and precision in achieving user-defined ablation spatial profile, drilling, cutting of materials or in-volume laser-induced modifications. In this scope, the possibility to generate a top-hat intensity distribution by spatially shaping the beam wavefront is studied in this work. An optimization of Zernike polynomials coefficients is conducted to numerically determine an adequate phase mask that shapes the laser intensity distribution following a targeted top hat distribution in the processing plane, usually at the focal length of a converging lens. The efficiency of the method is numerically investigated in the optimization by evaluation of the root mean square error (RMS) between the top-hat target and the calculated laser distribution in the far field. We numerically verify that acceptable top-hat beam shaping of various size can be achieved with a sufficient number of Zernike polynomials, opening the way to phase mask calculations adapted to the wavefront modulator ability to reproduce Zernike polynomials.

Paper Details

Date Published: 27 April 2016
PDF: 7 pages
Proc. SPIE 9893, Laser Sources and Applications III, 989312 (27 April 2016); doi: 10.1117/12.2227892
Show Author Affiliations
Cyril Mauclair, Lab. Hubert Curien, CNRS, Univ. de Lyon (France)
GIE Manutech-USD (France)
Nicolas Faure, Lab. Hubert Curien, CNRS, Univ. de Lyon (France)
GIE Manutech-USD (France)
Julien Houzet, Lab. Hubert Curien, CNRS, Univ. de Lyon (France)

Published in SPIE Proceedings Vol. 9893:
Laser Sources and Applications III
Jacob I. Mackenzie; Helena JelÍnková; Takunori Taira; Marwan Abdou Ahmed, Editor(s)

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