Imaging of Finite Amplitude Ultrasonic Waves by Bragg Diffraction of Light.
TENNESSEE UNIV KNOXVILLE ULTRASONICS LAB
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Light which has undergone Bragg diffraction by Ultrasonic waves produces diffraction orders which actually contain images of the ultrasonic wavefront. This report includes observation and discussion of this first-order imaging. In addition, this report includes observation and discussion of higher order imaging which occurs when ultrasonic waves of finite amplitude are used. The conditions for dominance of Bragg diffraction over regular diffraction are examined in relation to this higher order imaging, which is characterized by the appearance of multiple images in the higher diffraction orders. A transmission filter plate placed in the ultrasonic beam reveals that in addition to scattering and rescattering of light from the fundamental ultrasonic frequency, scattering of light from the second harmonic of the ultrasonic wave can be observed. The theory of Bragg diffraction of light by ultrasonic waves has been used to account for experimental observations of first-order imaging. This theory has been extended to account for experimental observations in higher order imaging by relating it to multiple scattering of the light by the ultrasonic wave. Author
- Solid State Physics