Enlarging viewing angle of computer-generated holograms

We investigate the use of lens-less Fourier hologram to enlarge viewing angle of the computer-generated holograms (CGH) whose resolution is relatively low such as a photographic reduction. For image reconstruction, this hologram requires the point illumination source near the hologram. To avoid the use of such special illumination, we made secondary hologram with collimated reference beam and the reconstructed beam of the CGH. The second hologram has wide viewing angle and can be reconstructed with collimated white-light illumination.