High Frequency Acoustic Holography in Solids
Acoustic holography in solids is of direct interest for the observation of defects within the solid. There is, however, another strong motivation for interest in solids: although the attenuation of sound in liquids becomes very large at frequencies in the UHF, it is possible to work with extremely thin liquid cells within the solid, the object to be imaged being introduced into the cell (see Figure 1). An imaging system using this technique at an acoustic frequency of 50 MHz has been reported(1). The work described here is an extension of this technique to a frequency of 150 MHz.
KeywordsShot Noise Reference Wave Surface Vibration Phase Sensitive Detector Angular Aperture
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