Fig. 1: Holographic MR display system.
From: Synthetic aperture waveguide holography for compact mixed-reality displays with large étendue
a, An illustration of the synthetic aperture waveguide holography principle. The illumination module consists of a collimated fibre-coupled laser, a MEMS mirror that steers the input light angle, and a holographic waveguide. Together, these components serve as a partially coherent backlight of the SLM. The SLM is synchronized with the MEMS mirror and creates a holographic light field, which is focused towards the user’s eye using an eyepiece lens. Our design achieves an ultra-thin form factor as it consists only of flat optical elements and it does not require optical path length to form an image. The steered illumination mechanism produces a synthetic aperture, which supports a two-orders-of-magnitude larger étendue than that intrinsic to the SLM. Our angle-encoded holographic waveguide and apochromatic holographic lens design solve bidirectional diffraction noise and chromatic dispersion issues, respectively. b, An exploded view of the schematic image and captured photos of the holographic MR display prototype. The use of thin holographic optics achieves a total optical stack thickness of less than 3 mm (panel to lens). Top- and side-view photographs of the prototype are shown.
