Applying multi-focus filtering plane in double-step Fresnel diffraction method for enhanced holographic projection region

Computer-generated holography has been anticipated in augmented reality (AR) since it can fully provide multi-depth 3D information to users, but speckle noises are often accompanied as one of the most significant degradation factors. Since complex amplitude encoding suppress noises, applying double-phase a lensless holographic projection system using double-step Fresnel diffraction (DSF) algorithm reported reduce those noises. However, single filtering focus at virtual focal plane might significantly region compared maximum bandwidth spatial light modulator. In this paper, we applied multiple foci for DSF method with off-axis phase encoding, which expand and is applicable display images DSF. Numerical analysis conducted image quality conventional shows that performance does not degrade so much number increase. We expect proposed be useful optical systems such AR head-up display.