Wave front phase and amplitude reconstruction techniques using multiple intensity patterns

The recording of the volume speckle field from an object at different planes, combined with the wave propagation equation allows the reconstruction of the wave front phase and amplitude without requiring a reference wave. The main advantage of this single-beam multiple-intensity reconstruction (SBMIR) technique is the simple experimental setup due to the fact that no reference wave is required as it is in the case of holography. In this study the method is applied to the investigations of diffusely transmitting and reflecting objects. The effects of different parameters on the quality of reconstructions were investigated by simulation and experiment. Significant improvements are observed when the number of intensity measurements is 15 or more and the sequential measurement distance is 0.5 mm or larger. Performing two iterations during the reconstruction process using the calculated phase also leads to better reconstructions. The results from simulation and experiments agreed well. Subsequent work has shown that super image methods like shifting the camera a distance of half-pixel in the lateral directions enhance the sampling of speckle patterns and lead to better reconstructions. This allows to the possibility of recording wave fields from larger test objects.