Modeling and optimizing the chromatic holographic waveguide display system

A ray-tracing model is developed based on coupled wave theory for a volume holographic grating, which is the most important element of the holographic waveguide display but not accessibly integrated in current optical design software. The model fully and faithfully represents the angular selectivity, wavelength selectivity, polarization, and other properties for the in-coupling, out-coupling, and expansion gratings. It is especially important that the model is compatible with the current optical design software. In this paper, combining with other mature optical simulation functions of Zemax, integrated models are built for typical holographic waveguide display configurations, including image source, collimation element, gratings, waveguide plates, and approximate eye. It could provide the retina image at different viewing positions, based on which the main performance characteristics of a holographic waveguide display, such as field of view, color uniformity, eye box, and light efficiency, could be easily derived. Consequently, it provides a valuable guiding approach for the design and optimization of holographic waveguide displays.