In the frame of science in microgravity, the investigation of dendritic growth in a solidification process has been chosen as a test case in order to determine the ultimate performance and the limits of interferometric optical tomography, a well dedicated optical diagnostic tool for transparent media. In the frame of 3D-shape measurements on the morphology of transparent succinonitril directional solidification front, the relatively slow temporal evolution of the solidification front allow to record tomographic projections during 30 seconds without having modifications. This would lead to the possibility to use a rotating device holding the sample in order to record sequentially the different views or set of views of the tomograph. Interferometry through its high sensitivity to refractive index variation is able to discriminate between solid phase and its surrounding solution. Due to a high number of parameters involved in tomographic measurements and reconstruction, it was necessary to analyze step by step their influences.
Representative static model scenes have been manufactured and in depth independently characterized by X-ray microtomography in air. The same model scenes have been inserted into a single arm phase-shift Mach-Zehnder interferometer again by rotating object in order to acquire up to 256 projections. Finally a tomographic reconstruction process has been performed, the results of which were compared to the reconstructions gained from the micro x-ray measurements. This work shows the potential of interferometric optical tomography as well as its limits.© (2005) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.