Subwavelength spatial light modulator for holographic augmented reality applications

Computer-Generated Holography (CGH) offers compelling advantages for near-eye Augmented Reality (AR) applications. Unlike waveguide-based approaches, holographic displays are capable of achieving natural 3D image formation, thereby mitigating the well-known issue of Vergence-Accommodation Conflict (VAC). Additionally, holography as a wavefront-control technology supports optical aberration correction in software, which applies to aberrations induced by the optical engine, as well as those associated with the user’s prescription. While these aspects of CGH have been known for several decades, the practical implementation of Holographic AR has been limited by hardware. To address these limitations, Swave Photonics developed a subwavelength Spatial Light Modulator (SLM) based on Phase-Change Material pixels on a silicon backplane, achieving a pixel pitch below 300 nm. This unlocks a path to compact optical engines that do not require pupil replication to achieve a sufficient eyebox and Field of View (FoV). In this paper, we present experimental validation of algorithms and optical architectures using static chip prototypes, and we demonstrate color projection without the need for color filters or time-sequential refresh.