Frequency analysis of digital holography with reconstruction by convolution

A coherent optical imaging system consisting of recording a digital hologram by a CCD array and numerical reconstruction of the complex wavefield by the convolution method is subjected to a frequency analysis. The point spread function of such a system is a sinc function whose width depends on the aperture defined by the CCD array and parameters of the transfer function used in the reconstruction. A narrow point spread function and thus a sharp reconstructed image can be obtained by the numerical concept of cascaded free-space propagation, which is introduced and demonstrated.