Enhancement of image quality utilizing time multiplexing phase only holograms

The purpose of computer-generated holography (CGH) is to generate arbitrary illumination patterns by modulating a coherent light beam. The possible applications of CGH include for example: optical testing, wavelength-selective switching, optical tweezers, and display technologies. For most applications, illumination patterns with high efficiency and a high contrast ratio are required. One of the major challenges related to CGH is the generation of a high signal to noise ratio to achieve the desired results of an effective and high-contrast illumination pattern. With emerging MEMS-based phase modulators, higher modulation speeds become accessible, resulting in higher frame rates than in existing LC based micro-displays. This high modulation speed enables the development of new algorithms for CGHs, which benefit from the high frame rate and utilize the high modulation speed to improve the contrast and image quality. This paper introduces a novel algorithm to generate time multiplex holograms (TMH). Using the TMH method, various illumination patterns for future automotive exterior projection scenarios are generated. To verify the applied method, numerical simulations and optical experiments are performed and indicate good consistency. Finally, the TMH results are compared with holograms generated using the Gerchberg-Saxton algorithm for computer-generated holograms (GS).