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Proceedings Paper

Real-time measurement of two-dimensional birefringence
Author(s): Keigo Itoh; Teruhisa Okhawa; Yongchang Zhu; Tatsuo Takada; Takashi Maeno
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Paper Abstract

The photo-elastic fringe pattern measurement technique is a nondestructive method widely used to measure the mechanical stress distribution inside solid materials. The mechanical stress distribution is evaluated by generating the photo-elastic fringe pattern and counting the number of isochromatic fringes (dark lines). If the amount of the mechanical stress is very small, however, and the corresponding birefringence is smaller than t radians, no fringe lines are produced. This method is, therefore, not suitable when the amount of the mechanical stress is small. Furthermore, ii the azimuth angle of the mechanical stress is to be measured, the sample needs to be rotated. We therefore developed a highly sensitive measurement system suitable for measuring birefringence distributions smaller than 7r radians by using an electro-optical phase modulator (Pockels cell) and a two-dimensional lock-in amplifier.1 This system can also measure the azimuth angle simultaneously without rotating the sample. Here we report the principle of this two-dimensional measurement system and give the results of measuring the 2-D birefringence distribution in PMMA fixed beam.

Paper Details

Date Published: 16 August 1996
PDF: 4 pages
Proc. SPIE 2873, International Symposium on Polarization Analysis and Applications to Device Technology, (16 August 1996); doi: 10.1117/12.246252
Show Author Affiliations
Keigo Itoh, Musashi Institute of Technology (Japan)
Teruhisa Okhawa, Musashi Institute of Technology (Japan)
Yongchang Zhu, Musashi Institute of Technology (Japan)
Tatsuo Takada, Musashi Institute of Technology (Japan)
Takashi Maeno, Musashi Institute of Technology (Japan)

Published in SPIE Proceedings Vol. 2873:
International Symposium on Polarization Analysis and Applications to Device Technology
Toru Yoshizawa; Hideshi Yokota, Editor(s)

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