Characterization of vibrations with holography-based methods

The study of vibrations is of great interest in many scientific fields (vibroacoustics, aeroacoustics), in industry (noise reduction, weight reduction of structures) and for bio-imaging (properties of products, in-vivo imaging). Traditionally, laser vibrometers, with or without scanning, are the tools most widely used by experimenters, as they have been technologically mature for several years. However, although they are non-contact and therefore non-intrusive, they cannot directly provide a "one-shot", wide-field and sufficiently resolved image of the vibratory phenomena under study. Among alternative full-field and contactless solutions, three methods coexist in the literature: 3D vision with several cameras and image correlation processing; deflectometry, which is similar to interferometric methods in terms of processing, but requires mirror-quality surfaces; and holography, which is universal in its appeal in various fields such as 3D display, microscopy, tomography, lithography, coronography or metrology.

This booklet is dedicated to the presentation of all vibration measurement methods based on holography. The first part presents the principles of the many holographic methods available in the literature. The second part deals with the measurement of vibrations generated under different excitation regimes: controlled sinusoidal, large amplitude and shock regimes. The last part of the article is dedicated to the cineholography technique. Each section is amply illustrated by a variety of examples, demonstrating the richness and diversity of possible applications for holographic methods. A list of bibliographical references will enable the reader to delve deeper into the subject.