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Matériaux organiques microstructurés et optique non linéaire: 1) Nanocristaux organiques en matrice sol-gel pour l'optique quadratique, 2) Polymérisation initiée par absorption à deux photons pour la microfabrication 3D

Abstract : In this report, we present two research topics which emphasize the relationship between nonlinear optics and microstructured organic materials. The first part is dedicated to the study of the quadratic nonlinear optical properties of a new range of materials: organic nanocrystals embedded in sol-gel films. Nanocrystals are obtained from well-known nonlinear optical molecules. However, as second order nonlinear processes require a non-centrosymmetric structure, we have studied the possibility to orient the nanocrystals and create a polar order using electric-field poling. The poling process was monitored using second-harmonic generation. This experimental technique brought a better understanding of the orientation and relaxation mechanism in this material, which is essential in trying to improve the efficiency and stability of its nonlinear properties. In the second part of this work, a third-order nonlinear process (two-photon absorption) was employed to initiate polymerization reactions and fabricate complex structures in three-dimension with a submicron resolution. Using a molecular engineering approach, new photoinitiators with enhanced two-photon absorption cross-sections have been designed and studied in terms of their two-photon absorption and initiation efficiency. We show that microfabrication experiments could be achieved with low-cost and low-power lasers using our photoinitiators. A kinetic model is proposed to relate the progression of the polymerization process to the material and irradiation characteristics. These considerations lead to better understanding and control over the spatial resolution of the polymerized structures.
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https://tel.archives-ouvertes.fr/tel-00008089
Contributor : Irène Wang <>
Submitted on : Monday, January 17, 2005 - 9:52:40 AM
Last modification on : Tuesday, September 11, 2018 - 11:00:02 AM
Long-term archiving on: : Friday, April 2, 2010 - 9:07:19 PM

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  • HAL Id : tel-00008089, version 1

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Citation

Irène Wang. Matériaux organiques microstructurés et optique non linéaire: 1) Nanocristaux organiques en matrice sol-gel pour l'optique quadratique, 2) Polymérisation initiée par absorption à deux photons pour la microfabrication 3D. Physique Atomique [physics.atom-ph]. Université Joseph-Fourier - Grenoble I, 2002. Français. ⟨tel-00008089⟩

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