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Measurements of ultrasonic fields with optical diffraction tomography
A Holm1, H W Persson, K Lindström
1Department of Electrical Measurements, Lund Institute of Technology, Sweden.
Ultrasound in Medicine & Biology
|January 1, 1991
Summary
This study introduces a novel light diffraction method for measuring ultrasonic pressure and phase. The technique utilizes Raman-Nath diffraction and tomography algorithms for precise beam cross-section analysis.
Area of Science:
- Acoustics
- Optics
- Medical Imaging
Background:
- Accurate measurement of ultrasonic fields is crucial for various applications.
- Existing methods for ultrasonic pressure and phase measurement have limitations.
Purpose of the Study:
- To develop and validate a new light diffraction technique for measuring ultrasonic pressure and phase.
- To apply tomography algorithms for reconstructing the ultrasonic field in a cross-section.
Main Methods:
- Utilizing light diffraction based on the Raman-Nath model for continuous-wave ultrasound.
- Employing tomography algorithms, specifically an algebraic reconstruction technique (ART), on diffracted light intensity data.
- Reconstructing the pressure and phase distribution in a plane perpendicular to the ultrasound propagation vector.
Main Results:
- The diffracted light intensity provides an integrated measure of sound pressure, analogous to X-ray tomography.
- Successful reconstruction of the measurement plane was achieved using 10 projections.
- The method is applicable for Raman-Nath parameter values up to 2.3.
- Experimental results show good agreement with miniature PVDF hydrophone measurements.
Conclusions:
- Light diffraction combined with tomography offers a viable method for non-invasive ultrasonic field characterization.
- The developed technique allows for detailed measurement of ultrasonic pressure and phase distributions.
- This approach has potential for applications requiring precise ultrasonic field mapping.