Abstract

Visualizations of the ultrasonic field, which is a moving phase object, are of special interest for NDT evaluation, acoustooptic information processing, nonlinear acoustics, etc. Early work showed the intensity distribution of the low frequency acoustic field either by the Schlieren method, which is based on the geometric optics concept of ray bending, or by diffraction phenomenon. Later, the wavefront of ultrasonic traveling waves, which gives important phase information, could be visualized by an extremely short pulsed laser beam. Unfortunately, this theory is ambiguous and the equipment is costly.

© 1989 Optical Society of America