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Contribution à la métrologie de l'indice de réfraction et de l'absorption non-linéaires en régime nanoseconde : amélioration de la méthode de Z-scan et simulations numériques

Abstract : When a high power laser beam goes through a transparent material, self-focusing may lead to a degradation of the wave surface quality or to a damage of the material. In order to have a better understanding of these phenomena, it is crucial to obtain an accurate measurement of the nonlinear refractive index. In the nanosecond regime, several mechanisms may lead to a photoinduced variation of the nonlinear refractive index. In order to study the photoinduced variations of the nonlinear refractive index in the nanosecond regime, a sensitive measurement bench of small nonlinear refractive indexes has been developed. This measurement bench is based on a beam distortion measurement method : the Z-scan method. Thanks to a perfect mastery of the metrology and a very general simulation algorithm, the nonlinear refractive index can be measured with a sensitivity equal to lambda/3000 on the optical path variation inside the material and an absolute error estimated to be 12% at 1064nm and 16% at 532nm on the nonlinear refractive index. In these conditions, the nonlinear refractive index of silica and BK7 was measured at 1064nm and 532nm. A non negligible contribution of electrostriction and thermal effects was noticed.
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Contributor : Thomas Olivier <>
Submitted on : Friday, May 13, 2005 - 6:42:23 PM
Last modification on : Tuesday, October 20, 2020 - 3:10:33 AM
Long-term archiving on: : Friday, April 2, 2010 - 9:22:44 PM

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  • HAL Id : tel-00009261, version 1

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Thomas Olivier. Contribution à la métrologie de l'indice de réfraction et de l'absorption non-linéaires en régime nanoseconde : amélioration de la méthode de Z-scan et simulations numériques. Physique Atomique [physics.atom-ph]. Université de droit, d'économie et des sciences - Aix-Marseille III, 2004. Français. ⟨tel-00009261⟩

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