Axial sub-nanometer accuracy in digital holographic microscopy

We present state-of-the-art dual-wavelength digital holographic microscopy (DHM) measurement on a calibrated 8.9 nm high chromium thin step sample and demonstrate sub-nanometer axial accuracy. By using a modified DHM reference calibrated hologram (RCH) reconstruction method, a temporal averaging pro...

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Bibliographic Details
Published in:Measurement science & technology 2008-07, Vol.19 (7), p.074007-074007 (8)
Main Authors: Kühn, J, Charrière, F, Colomb, T, Cuche, E, Montfort, F, Emery, Y, Marquet, P, Depeursinge, C
Format: Article
Language:English
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Summary:We present state-of-the-art dual-wavelength digital holographic microscopy (DHM) measurement on a calibrated 8.9 nm high chromium thin step sample and demonstrate sub-nanometer axial accuracy. By using a modified DHM reference calibrated hologram (RCH) reconstruction method, a temporal averaging procedure and a specific dual-wavelength DHM arrangement, it is shown that specimen topography can be measured with an accuracy, defined as the axial standard deviation, reduced to at least 0.9 nm. Indeed for the first time to the best of our knowledge, it is reported that averaging each of the two wavefronts recorded with real-time dual-wavelength DHM can provide up to 30% spatial noise reduction for the given configuration. Moreover, the presented experimental configuration achieves a temporal stability below 0.8 nm, thus paving the way to Angstrom range for dual-wavelength DHM.
ISSN:0957-0233
1361-6501
DOI:10.1088/0957-0233/19/7/074007