Determination of wave fields with high space-bandwidth product by means of sub pixel sampling and irregular phase shifting

In this paper we present a new approach for the measurement of multiple digital holograms at different positions in space that can be combined to one high resolution hologram. The reconstruction is based on a phase shifting approach, where the CCD sensor and the reference wave are moved simultaneously along different positions in x and y. An inclination of the reference wave induces a phase shift when reference wave and CCD sensor are moved. In contrast to temporal phase shifting methods, the approach does not require any of the images to be recorded at the same positions, which is an important step towards the long-term prospect of a hand held holographic sensor that can measure wave fields with high resolution just by movement of the hand. Also, the phase shifts and shifts of the CCD sensor do not necessarily need to be determined from the experimental setup. They can also be reconstructed from the recorded images if there is a region in Fourier space where no aliases are present. We present a model for the recording process and an approach for the reconstruction, as well as experimental results demonstrating the validity of the new method.