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Proceedings Paper

Spatio-temporal structures of laser-induced anisotropy and applications
Author(s): Xiao Hong Chen; Helmuth Berger; Roland Chaux
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Paper Abstract

We report new observations of optical spatio-temporal structures formed in a naturally isotropic solid-state material. The phenomenon is due to laser-induced anisotropy. In fact, a part of the optical power is absorbed by the material which leads to the sample heating,the refractive index of the medium becomes laser power dependent under strong beam intensity excitation. This refractive index variation modifies in turn the optical polarization of the beam. As a consequence of polarization pattern is induced. If the material is placed near the laser beam focus, usually the induced depolarization is strong due to the high beam intensity. We observed however, that the induced depolarization is reduced sharply near the focus. This phenomenon was not observed up to now. We have developed a model which shows that both the index variations in transverse and longitudinal directions contribute to the phase shift, and are responsible for the depolarization. As a result, the competition between these two contributions plays a key role in the polarization changes near focus. Our observation is accounted for by a transient nonlinear refractive index model. Good agreement with the theoretical description of the pattern formation is obtained. We found that in some appropriated experimental configurations, these spatio-temporal structures present advantages in the applications, e.g. in conceiving a 2D vectorial optical sensor.

Paper Details

Date Published: 5 October 1999
PDF: 8 pages
Proc. SPIE 3779, Current Developments in Optical Design and Optical Engineering VIII, (5 October 1999); doi: 10.1117/12.368193
Show Author Affiliations
Xiao Hong Chen, Univ. de Bourgogne (France)
Helmuth Berger, Univ. de Bourgogne (France)
Roland Chaux, Univ. de Bourgogne (France)


Published in SPIE Proceedings Vol. 3779:
Current Developments in Optical Design and Optical Engineering VIII
Robert E. Fischer; Warren J. Smith, Editor(s)

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