Abstract

Photorefractive crystals are promising recording media for a variety of applications including holographic interferometry. This is due to properties such as instantaneous hologram formation (self-development), high-data storage capacity (3D storage), high sensitivity and resolution, erasability and reusability, etc. In this paper, experimental production of interferograms using double-exposure holography in crystals of lithium niobate is reported. The methodology necessary for recording and retrieving flow-field information using photorefractive holographic recording in these crystals is discussed as well as the critical parameters involved, such as crystallographic orientation, crystal doping levels, ratio of reference to object beam power, and the required exposure energy levels. Experiments using lithium niobate crystals with various iron-doping levels in both reflection and transmission geometry have been performed. Various phase objects such as a nozzle discharge from a nitrogen bottle and airflow over an airfoil have been recorded. Qualitative results showing the reconstructed interferograms obtained via this technique are presented and compared with corresponding results obtained using photographic film as the recording medium.

© 1986 Optical Society of America