Large step-height measurements using multiple-wavelength holographic interferometry with tunable laser diodes.
J Opt Soc Am A Opt Image Sci Vis
; 25(12): 3013-20, 2008 Dec.
Article
em En
| MEDLINE
| ID: mdl-19037392
ABSTRACT
Accurate measurement of large step heights using multiple-wavelength holographic interferometry is realized using laser diodes. Due to the high-resolution wavelength tunability of such lasers, a pair of holograms with a wavelength difference of less than 0.01 nm is recorded and used to extract a phase difference having a large synthetic wavelength. Phase differences with synthetic wavelengths ranging from 2.5 to 73 mm are extracted by using pairs of holograms with wavelength differences between 0.3 and 0.01 nm. By combining the phase differences, measurements with a step height of 18 mm and an rms error of 0.04 mm could be achieved. The requirements for performing the phase unwrapping are discussed. Precise knowledge of the recording wavelengths is required to correctly perform this unwrapping.
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Base de dados:
MEDLINE
Idioma:
En
Ano de publicação:
2008
Tipo de documento:
Article