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Updated: Jun 3, 2026

Shaping the Amplitude and Phase of Laser Beams by Using a Phase-only Spatial Light Modulator
Published on: January 28, 2019
Variant of the method of Fox and Li dedicated to intracavity laser beam shaping
Emmanuel Cagniot1, Michael Fromager, Thomas Godin
1Centre de Recherche sur les Ions, les Matériaux et la Photonique, Unité Mixte de Recherche 6252, Commissariat à l'Énergie Atomique, Centre National de la Recherche Scientifique, École Nationale Supérieure d’Ingénieurs de Caen, Université de Caen, 6 Bd Maréchal Juin, F-14050 Caen Cedex, France
Abstract:
We present a variant of the method of Fox and Li [Bell Syst. Tech. J. 40, 453 (1961); Proc. IEEE 51, 80 (1963)] dedicated to intracavity laser beam shaping for resonators containing an arbitrary number of amplitude and phase diffractive optics. Contrary to Fox and Li, the starting point is the desired field. The latter is injected into the usual sequence of lenses representing just a single round trip, and the optimization process iterates until the input and the output fields match as much as possible. We illustrate this technique by deriving a simple model for generating single cylindrical TEM(p0) modes, thanks to a π-phase plate placed inside a plano-concave cavity. The experimental validation attests an excellent agreement with numerical predictions.

