ASA 124th Meeting New Orleans 1992 October

1aPA3. An investigation using an optical probe to study ultrasonic pulses.

Jo Hays-Stang

Bill D. Cook

Dept. of Mech. Eng., Univ. of Houston, 4800 Calhoun, Houston, TX 77204-4792

With care and working within well-defined constraints, it has been previously demonstrated that a laser beam and a fast responding light detector could be made to behave as a linear line receiver of low megahertz sinusoidal ultrasonic waves. It is a sufficiently good line receiver so that the principles of tomography can be used to unfold the sound field. Many of the constraints are frequency dependent and the question arises as to whether a laser beam could be used to investigate a pulse of moderate bandwidth. The studies show that major features of the signal from the line detector can be accounted for when the sound field is produced by a commercial NDE transducer driven with a known Gaussian time pulse.