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Imaging micro-optical components with short coherent digital holographic microscopy

: Stürwald, S.; Schmitt, R.


Wyrowski, F. ; Society of Photo-Optical Instrumentation Engineers -SPIE-, Bellingham/Wash.:
Optical modelling and design : 13 - 15 April 2010, Brussels, Belgium
Bellingham, WA: SPIE, 2010 (Proceedings of SPIE 7717)
ISBN: 978-0-8194-8190-0
Paper 77170O
Conference "Optical Modelling and Design" <2010, Brussels>
Conference Paper
Fraunhofer IPT ()

The application of digital holographic microscopy offers quantitative phase contrast imaging of reflective and (partially) transparent samples. Low coherent light sources enable an increased resolution in phase shifting digital holography by the reduction of stray light and multiple reflections in the experimental interferometer setup. Therefore light emitting diodes (LED) are utilized. Here, the effects on the reconstruction quality by considering the whole spectrum of the light source are investigated. Furthermore, the propagation of the complex wave fronts, which are determined by digital holography, and used for re- and multifocusing, is modified to light sources with a spectral width wider than that of typical laser light sources. Therefore, the propagation algorithm using the convolution method as a solution of the Fresnel-Kirchhoff diffraction integral according to the first Rayleigh-Sommerfeld approximation is extended by an additional integral to take into account the spectral width of low coherent light sources. Numerically, in the new approach the supplementary integral is realized by a discrete sum considering a finite set of wavelengths. Specifically, the results of the modified algorithm are compared with common algorithms with respect to resolution and image sharpness.