Display Of HF Acoustic Holograms Utilizing Liquid Crystals

Recent advances in the field of acoustic holography have shown it to be a very promising technique for the non-destructive imaging of the interiors of opaque objects. High resolution acoustical holography would enable the mapping and characterization of minute hidden flaws in materials, and facilitate the study of their temporal propagation. Acoustical methods are particularly well suited to the visualization of flaws because the large impedance mismatch presented by such a defect causes a strong reflected signal and a pronounced display. It may well be possible to visualize features of a specimen which go undetected by conventional methods.