Methods for Acoustic Holography and Acoustic Measurements.
NAVAL UNDERWATER SYSTEMS CENTER NEW LONDON CONN NEW LONDON LAB
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A novel four step acoustical holographic imaging system is described and several means to implement it are theoretically and experimentally analyzed. The holographic sound image converter, consisting of an optical holographic interferometer and an acoustic coupler is introduced, analyzed, and compared to existing acoustic detectors and a number of its advantages are cited. The new technique of shifted reference holographic interferometry is presented. Also, a detailed study is conducted concerning the development and testing of a mechanical velocity transformer consisting of two lossy, nearly quarter-wave plates. Modified author abstract