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Proceedings Paper

Holographic optical correlation
Author(s): Diana Tentori
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Paper Abstract

Holographic interferometry is a differential technique used to detect small changes that can be translated to phase variations in the light transmitted or reflected by the object. Phase fluctuations are shown as interference fringes produced by the superposition of the wavefront in its original state, reconstructed by the hologram, and the modified wavefront coming from the real object. In order to reconstruct the original beam, the hologram is illuminated with the reference beam used to record it. Making the analysis ofthe resultant interference pattern is not easy. At first, a bidimensional mapping of the phase distribution along the interferogram must be performed. Then using fringe positions, the interference pattern must be interpreted. The detection of the phase in each point of the interferogram and the location of its individual position require a complicated detection system or a well trained operator. In this work we analyze the sensitivity of holographic optical correlation, a technique that gives a global evaluation of the changes in the object through the measurement of intensity variations in a single position. This technique combines the three-dimensional storage capacity ofholography with the integrated response given by the correlation of two wavefronts. Utilizing a Van der Lught type filtering system and a common path holographic interferometer the changes introduced in the object wavefront were studied. To do so, the reference object wavefront is recorded in the hologram. Afterwards the modified object wavefront is used to illuminate the hologram plate. Using a lens the intensity variations associated to the correlation of both object wavefronts is obtained in the direction of the reference beam used to record the hologram. The detector is positioned at the image point related with the collimated reference beam used to record the hologram. The intensity variations measured there give us a global evaluation of the changes in the object beam. Experimental results considering different objects and sources of change are shown.

Paper Details

Date Published: 15 February 1993
PDF: 5 pages
Proc. SPIE 1756, Interferometry: Applications, (15 February 1993); doi: 10.1117/12.140808
Show Author Affiliations
Diana Tentori, CICESE (United States)

Published in SPIE Proceedings Vol. 1756:
Interferometry: Applications
Ryszard J. Pryputniewicz; Gordon M. Brown; Werner P. O. Jueptner, Editor(s)

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