Evaluation of the performance of tilt scanning interferometry for tomographic imaging and profilometry

In this paper we investigate the performance of Tilt Scanning Interferometry in tomographic imaging and profilometry applications, with an emphasis on the factors that limit the quality of image reconstruction. Depth resolution is mainly degraded by a frequency chirp that appears in the temporal interference signal when a large tilting range is scanned. It is shown through a numerical simulation that the chirp depends on the curvature of the illumination wavefront and also on the position of the pivot axis of the illumination beam. Data processing methods are proposed to overcome these limitations and their effects are illustrated with experimental measurements of opaque surfaces and a weakly scattering phantom with internal features. The effect of speckle decorrelation is also discussed.