Noninterferometric Tomographic Reconstruction of 3D Static and Dynamic Phase and Amplitude Objects

Non-interferometric intensity based methods of phase retrieval such as the transport of intensity (TI) employs a simple experimental technique for amplitude and phase reconstruction of a static object by capturing several diffraction patterns at different observation planes. The purpose of this work is to numerically and experimentally extend this technique to moving phase and amplitude objects. The simulation part is done based on solving the TI equation (TIE) using the Fast Fourier Transform (FFT) method, and the amplitude and the calculated phase in the detection plane is numerically back-propagated to the object plane using the paraxial transfer function. Furthermore, we illustrate how a static 3D phase and/or amplitude object can also be reconstructed tomographically by illuminating it at multiple angles. For illustration purposes, the object is mounted on a rotating stage and multiple diffraction patterns are captured for different angles and at different observation planes. The reconstructed optical fields are tomographically recomposed to yield the final 3D shape using a simple multiplicative technique. The tomographic technique can be generalized for the case of 3D moving objects. Finally, we have used TIE to determine the phase induced in a liquid due to heating by a focused laser beam, which causes self-phase modulation of the beam.