Laser-based ultrasonic systems for non destructive testing and evaluation rely on the coherent detection of phase modulation imprinted on the beam by the vibrating surface. As this detection principle requires an exact superposition of the wave issued from the target with a plane reference wave, these devices only operate with a plane wave signal beam. This constraint strongly limits the spread of laser ultrasonic systems in industry. We will show how the use of dynamic holographic materials allows to implement adaptive interferometers with a large light gathering power. Two different systems that have recently led to industrial developments, will be presented and compared. Requirements for the dynamic material to be used will be discussed. Performances for ultrasound detection will be finally given.

Date Published: 29 April 1999
PDF: 6 pages
Proc. SPIE 3729, Selected Papers from International Conference on Optics and Optoelectronics '98, (29 April 1999); doi: 10.1117/12.346777

Published in SPIE Proceedings Vol. 3729:
Selected Papers from International Conference on Optics and Optoelectronics '98
Kehar Singh; Om Prakash Nijhawan; Arun Kumar Gupta; A. K. Musla, Editor(s)