Viewing angle enhancement for two- and three-dimensional holographic displays with random superresolution phase masks.
Holographic displays employing binary phase modulation have been demonstrated to be attractive on the grounds of efficiency and miniaturization, and they offer a plausible approach to two-dimensional (2D) and three-dimensional (3D) image projection and display. A novel algorithm--one-step phase retrieval--and corresponding hardware architecture have recently been proposed, providing the performance required for real-time holographic display. However, since viewing angle varies inversely with pixel size, very small display pixels are required to achieve a wide field of view. This is particularly problematic for 3D displays, as the requirement for a large display with small pixels has hitherto necessitated an unachievably large electrical bandwidth. We present a novel approach, utilizing fixed random pixelated quaternary phase masks of greater resolution than the displayed hologram, to dramatically increase the viewing angle for 2D and 3D holographic displays without incurring a bandwidth penalty or significantly degrading image quality. Furthermore, an algorithm is presented to generate holograms accounting for the presence of such a phase mask, so that only one mask is required.