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Proceedings Paper

Several micron-range measurements with sub-nanometric resolution by the use of dual-wavelength digital holography and vertical scanning
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Paper Abstract

Reflection digital holographic microscopy (DHM) is a very powerful technique allowing measuring topography with a sub-nanometer axial resolution from a single hologram acquisition. But as most of interferometer methods, the vertical range is limited to half the wavelength if numerical unwrapping procedure could not be applied (very high aspect ratio specimen). Nevertheless, it was already demonstrated that the use of dual-wavelength DHM allows increasing the vertical range up to several microns by saving the single wavelength resolution if conditions about phase noise are fulfilled (the higher the synthetic wavelength, the smaller the phase noise has to be). In this paper, we will demonstrate that the choice of a synthetic wavelength of about 17 microns allows measuring precisely a 4.463μm certified step. Furthermore, we will show the feasibility of a sub-nanometer resolution on a range higher than the synthetic wavelength by being able to map the dual-wavelength measurement on data acquired from a vertical scanning process, which precision is about 1 μm.

Paper Details

Date Published: 17 June 2009
PDF: 10 pages
Proc. SPIE 7389, Optical Measurement Systems for Industrial Inspection VI, 73891H (17 June 2009); doi: 10.1117/12.827338
Show Author Affiliations
Tristan Colomb, Lyncée Tec SA (Switzerland)
Jonas Kühn, Ecole Polytechnique Fédérale de Lausanne (Switzerland)
Christian Depeursinge, Ecole Polytechnique Fédérale de Lausanne (Switzerland)
Yves Emery, Lyncée Tec SA (Switzerland)

Published in SPIE Proceedings Vol. 7389:
Optical Measurement Systems for Industrial Inspection VI
Peter H. Lehmann, Editor(s)

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