TV holography measurements of underwater acoustic fields

Abstract

Members of our group have previously demonstrated that TV holography may be used to measure the amplitude and the phase distributions of a sound field in air. This technique is not limited to acoustic fields in air, but may be applied to acoustic fields in any transparent medium. Its applicability to ultrasonic fields in water is demonstrated in this Letter.

Underwater Acoustic Wavefront Visualization by Scanning Laser Doppler Vibrometer for the Characterization of Focused Ultrasonic Transducers

“…The most promising approach to develop new transducers capable of non-invasive visualizing acoustic wavefronts has been to consider optical metrology techniques. Specific examples of these methods can be identified as schlieren [ 2 ], Michelson interferometry [ 3 ], electronic speckle pattern interferometry (ESPI) [ 4 ] and laser Doppler anemometry (LDA) [ 5 ]. Michelson interferometry and LDA for acoustic analysis are both limited by the fact that they are mainly used as single-point techniques.…”

Characterization of Transducer Performance and Narrowband Transient Ultrasonic Fields in Metals by Rayleigh-Sommerfeld Backpropagation of Compression Acoustic Waves Measured with Double-Pulsed Tv Holography

“…[3,4] Truly non-invasive, all-optical alternatives were also developed by using a laser beam oriented orthogonally to the main propagation direction of the acoustic beam. A 2-D projection of the acoustic field on a plane perpendicular to the laser beam can thus be obtained, either with scanning laser vibrometers [5,6] or full-field optical techniques such as TV holography [7] or Schlieren imaging. [8] When combined with tomographic techniques, this configuration provides data in three dimensions and thus yields quantitative mappings of acoustic beams.…”

Visualising scattering underwater acoustic fields using laser Doppler vibrometry

“…Specific examples of previously reported applications of optical metrology techniques can be identified as; Schlieren [14], Michelson interferometry [15], Electronic Speckle Pattern Interferometry (ESPI) [16][17], and Laser Doppler Anemometry (LDA) [18]. The use of Michelson interferometry and LDA for acoustic analyses are both limited by the fact that they are single point techniques with no volumetric capability.…”