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Proceedings Paper

Enhanced multi-wavelength holographic profilometry by laser mode selection
Author(s): Mikiya Muramatsu; Eduardo A. Barbosa; Eduardo A. Lima; Marcos R. R. Gesualdi
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Paper Abstract

The application of multi-wavelength holography for surface shape measurement is presented. In our holographic setup a Bi12TiO20 (BTO) photorefractive crystal was the holographic recording medium and a multimode diode laser emitting in the red region was the light source in a two-wave mixing scheme. The holographic imaging with multimode lasers results in multiple holograms in the BTO. By employing such lasers the resulting holographic image appears covered of interference fringes corresponding to the object relief and the interferogram spatial frequency is proportional to the diode laser free spectral range (FSR). We used a Fabry-Perot etalon at the laser output for laser mode selection. Thus, larger effective values of the laser FSR were achieved, leading to higher-spatial frequency interferograms and therefore to more sensitive and accurate measurements. The quantitative evaluation of the interferograms was performed through the phase stepping technique (PST) and the phase map unwrapping was carried out through the Cellular-Automata method. For a given surface, shape measurements with different interferogram spatial frequencies were performed and compared, concerning measurement noise and visual inspection.

Paper Details

Date Published: 15 September 2006
PDF: 6 pages
Proc. SPIE 6341, Speckle06: Speckles, From Grains to Flowers, 63410W (15 September 2006); doi: 10.1117/12.695337
Show Author Affiliations
Mikiya Muramatsu, Cidade Univ. (Brazil)
Eduardo A. Barbosa, Cidade Univ. (Brazil)
Eduardo A. Lima, Univ. Estadual Paulista (Brazil)
Marcos R. R. Gesualdi, Univ. of Vale do Paraiba (Brazil)

Published in SPIE Proceedings Vol. 6341:
Speckle06: Speckles, From Grains to Flowers
Pierre Slangen; Christine Cerruti, Editor(s)

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