Speckle Photography with BaTiO<inf>3</inf> Crystal for the Measurement of In-plane Displacement Field Distribution of Distant Objects

A two-beam coupling configuration using a BaTiO3 crystal as recording medium for real-time displacement measurement of distant objects using a high coherent source such as frequency-doubled diode-pumped Nd: YAG laser is presented in this paper. Long coherence length of the laser permits to study the objects which are far away from the BaTiO3 crystal. The requirement however, is that both the objects and the recording stage should be vibration isolated, and influence of intervening medium must be negligible. © 1998 Published by Elsevier Science Ltd. All rights reserved.