Partiell kohärente Beleuchtung in der lateralen Shearing-Interferometrie

This thesis discusses the influence of a special spatially extended light source in lateral shearing interferometry, both in the two-beam case and for speckle interferometry. In particular, the use of diffractive elements is emphasized, whereby intrinsic errors of the experimental setups can be kept low and at the same time a high degree of flexibility can be achieved.

First, an approach for the simultaneous acquisition of both gradient fields by a common imaging is described that has the potential of a „single shot“ measurement. The consistent use of the presented shearing unit then leads to a setup that also enables the simultaneous acquisition, but also motivates the use of the partially coherent light source. The shape of the light source distribution – periodically arranged points on a rotating scatterer – and the resulting improvement of the measurement result are explained, which are bound to the spatial coherence of the light field.

Finally, for speckle interferometry by means of deformation measurements it is shown what influence the use of this light source has on the number of phase singularities located in the measured phase field.