Viewing angle analysis of reconstructed image from digital Fresnel hologram with enhanced numerical aperture

Abstract: The viewing-angle enlargement of a holographic image is a crucial factor for realizing the holographic display. The numerical aperture (NA) of digital hologram other than a pixel specification has been known to determine the angular field extent of image. Here, we provide a valid foundation for the dependence of viewing angle on the hologram numerical aperture by investigating mathematically the internal structure of the sampled point spread function showing a self-similarity of its modulating curves and especially, analyzing this scheme on the basis of quantum mechanical framework. The enhanced-NA Fresnel hologram generates the multiple images with a high resolution, which can lead to the higher viewing angle represented as the NA of whole aperture of hologram. Optical experiment shows the consistent result with quantum mechanical description of viewing angle of holographic images. Finally, we discuss the method for enlarging viewing angle of holographic image without sacrificing image size by using this scheme.