In the measurement of the amplitude of vibration of objects, holographic imaging techniques usually involve fringe counting; because of the limited resolution of the images, measurements of large amplitudes are not accessible. We demonstrate a technique that suppresses the necessity of fringe counting—frequency sideband imaging—where the order of the sideband is considered a marker of the amplitude. The measurement is completely local: no comparison with another reference point on the object is necessary. It involves a sharp variation of a signal, which makes it robust against perturbations. The method is demonstrated in an experiment made with a vibrating clarinet reed; phase modulations as large as 1000 rad have been measured.
© 2009 Optical Society of America
Original Manuscript: August 19, 2009
Manuscript Accepted: September 25, 2009
Published: November 24, 2009
F. Joud, F. Verpillat, F. Laloë, M. Atlan, J. Hare, and M. Gross, "Fringe-free holographic measurements of large-amplitude vibrations," Opt. Lett. 34, 3698-3700 (2009)
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