Comparison of double-phase hologram and binary amplitude encoding: holographic projection and vortex beam generation.

Utilizing computer-generated holograms is a promising technique because these holograms can theoretically generate arbitrary waves with high light efficiency. In phase-only spatial light modulators, encoding complex amplitudes into phase-only holograms is a significant issue, and double-phase holograms have been a popular encoding technique. However, they reduce the light efficiency.

Pixel-level phase filters for off-axis shifting of sinc envelope in holographic projection.

Off-axis projection is a common practice for reconstructions of Fourier holograms displayed on liquid crystal on silicon (LCoS) spatial light modulators (SLMs), as it spatially separates the image from the undiffracted light. Binary gratings encoded within the holograms enable maximum angular separation. However, as a result, two mirror images of equal intensities are present in the reconstruction.

Suppression of spurious image duplicates in Fourier holograms by pixel apodization of a spatial light modulator.

Holographic projectors and near-eye displays are a promising technology with truly three-dimensional, natural viewing and excellent energetic efficiency. Spatial light modulators with periodic pixel matrices cause image duplicates, which distract the viewer and waste energy of the playback beam. We present the engineering of the far field intensity envelope, which suppresses higher-order image duplicates in the simplest possible optical setup by physically changing the shape of modulator pixels with attached apodizing masks.

Photo-magnetic recording of randomized holographic diffraction patterns in a transparent medium.

Reconstructions from computer-generated holograms exhibit spurious duplicate images corresponding to higher diffractive orders, originating from the periodic pixels of a spatial light modulator. We explore the possibility of reducing their visibility by randomization of pixel positions at the stage of displaying of the holograms. Experimental validation is shown on a liquid crystal modulator and also in a promising photo-magnetic transparent cobalt-doped yttrium iron garnet, which exhibits spontaneous randomization of written patterns.

Aberration-corrected holographic projection on a two-dimensionally highly tilted spatial light modulator.

Image projection by holographic allows efficient and compact optical setups; nevertheless, the limited throw angle and 1:1 image aspect ratio are impractical. We present the method to increase the diffractive angle of a spatial light modulator in one and two directions by introducing the highly 2-dimensionally tilted illuminating beam. The inevitable image aberrations, such as astigmatism, for off-axis imaging are corrected by proper modifications of the phase patterns on the modulator.