Three-dimensional real-time measurements of ultrasonic waves in transparent solids.
A Doppler-shifted light-scattering technique, long used in velocimetry to yield 3-D flow information about liquids and gases, has been used for the first time to measure ultrasonic fields in solids. Unlike Bragg diffraction and interferometric methods previously used in solids, Doppler methods require no a priori assumptions about the sound field in order to obtain 3-D resolution. In addition, Doppler methods determine not refractive index changes but particle motion directly; thus the need to use the photoelastic constants of the medium to calculate strain data is eliminated.
Fick
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Palmer
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