Multifocal waveguide-based display in augmented reality

We present a waveguide-based near-eye display designed to enhance immersive augmented reality experiences. Unlike conventional waveguide displays that project virtual content onto a single focal plane, the proposed waveguide optics can display images across an extended depth range. This extension of focus cues is achieved through a multifocal holographic optical element (M-HOE) that functions as an output coupler on the waveguide. The M-HOE is fabricated by spatially implementing three distinct volume holographic gratings within a single photopolymer film, thereby serving as a trifocal miniaturized flat lens. Consequently, virtual content via the output coupler is spatially focused at three focal distances (-300, -600, and -1000 mm from the output coupler), as experimentally demonstrated in the AR display. Although this approach is in its early stages, it holds promise for alleviating the vergence-accommodation conflict, a significant challenge in head-mounted AR displays, thereby providing users with a truly immersive AR experience.