Method for overcoming the finite space-bandwidth limitation of digital holograms in holography

A digital hologram has a finite space-bandwidth, which determines the spatial resolution and angular field of view of its reconstructed image. However, higher space-bandwidth induces aliased replica patterns in the Fresnel diffraction. This study analyzes the spatial distribution of the angular spectrum in an undersampled hologram using angle modulation in the complex domain.The replica functions are identified as phase-modulated functions by multiples of the sampling frequency, with the spatial frequency range extending continuously from the original function into the regions of the replica functions. Simulations of optical imaging confirm the theoretical predictions, demonstrating that imaging performance beyond the space-bandwidth limitation of a digital hologram is achievable. Specifically, a method is proposed to address the challenge of limited viewing angles in holographic displays. This approach provides an alternative solution to overcome the constraints imposed by the finite space-bandwidth of digital holograms.