TRW Acousto-Optical Nonimmersion Flaw-Imaging System

Abstract

Several investigators^{1, 2, 3} have described techniques and experiments where objects in media opaque to light have been made visible by Bragg diffraction of light due to ultrasound scattered from the object viewed. These authors immersed the object viewed in water to aid the conduction of scattered sound into a light/sound interaction region. More recent published work also concerned immersed obj ects.^{4, 5} The work reported here extends previous results to formation of images of nonimmersed solid objects which require access from only one side. This is accomplished by using pulsed sound reflected from discontinuities within a test object composed of solid material. Nonimmersion is accomplished by transmitting and receiving sound through a membrane separating water in the light/sound interaction region from the test object.