We propose a polarization multiplexing structure based on multilayer reflective polarized volume holographic gratings(PVGs) to improve the field of view and brightness of the augmented reality waveguide display. The multilayer structure forms the splicing of different response bandwidths by stacking PVGs with different periodic components, and realizes the expansion of the wavelength (angle) bandwidth. The polarization multiplexing structure controls the polarization of the diffracted light by controlling the rotation direction of the liquid crystal pitch in the liquid crystal material, so that both left-hand and right-hand circularly polarized light are diffracted to enhance efficiency. Based on these two structures, the wavelength bandwidth of PVG is increased by 40 nm, the angular bandwidth is increased by 10°and the diffraction efficiency is nearly doubled. In order to verify the feasibility of these two structures, we use the holographic waveguide display with OLED as the image source. The demonstrated waveguide prototype shows a complete display with a diagonal field of view of 55°. The brightness of virtual image was measured as high as 1100 cd/m 2 with a transparency of 72% for ambient light.

We propose a two-dimensional exit pupil expansion (2D-EPE) design of a diffractive waveguide (DW) based on polarization volume grating (PVG). The designed waveguide structure and pupil expansion principle are introduced in this paper. The light propagation behavior and available field of view (FoV) of the proposed waveguide are investigated by simulations. In addition, the waveguide sample based on the proposed design is prepared, and an imaging system based on a monochromatic MicroLED projector is built for AR imaging experiments. The experimental results show that the prepared waveguide system can achieve a clear AR display with a diagonal FoV of 30° and obtain an exit pupil magnification of nearly 20 times compared to the entrance pupil size. The optical imaging efficiency was measured to be 3.85%, and the backward light leakage rate was as low as 8.7%. This work further enhances the feasibility and practicality of the PVG-waveguide technology and provides a promising candidate for AR-DW applications.

Near-eye holographic waveguide display system using novel reflective polarized volume gratings (RPVG) have lately gotten a lot of interest. However, from polarization characteristics to imaging simulation, there is no systematic approach based on RPVG. Here, a full methodology for solving this problem using the rigorous coupled wave analysis (RCWA) model is presented. This self-built RCWA model is used to examine the optical behavior of RPVG. This excellent portability of the RCWA model makes it possible for RPVG as a diffractive optical element, which is integrated into the commercial optical software Zemax via a self-compiled dynamic link library (DLL), and a full-color imaging simulation of the based-RPVG waveguide display system is obtained. Our work provides an instructive imaging analysis method using the RPVG for holographic waveguide display.

The field of view (FOV) of waveguide display systems based on volume holographic grating (VHG) is primarily constrained by the diffraction response bandwidth, which is currently insufficient to meet the need for AR immersive displays. Through the composite diffraction response bandwidths, redresponsive and green-responsive double-layer VHG structures are proposed to

In augmented reality diffractive waveguide technology, the light field needs to be collimated before being transmitted into the diffractive waveguide. Conventional schemes usually require additional collimating optics to collimate the light from the micro-image source and guide it into the waveguide in-coupling elements. In order to meet the needs of head-mounted devices and further miniaturize the equipment, this paper proposes a waveguide device that combines collimation and coupling by using a reflective polarization volume lens (PVL). A related model is also established and simulated to calculate the diffraction and transmission characteristics of the PVL element, and is then improved to fit the experiment. The diffraction lens studied in this paper has high diffraction efficiency with a large off-axis angle, which can fold the optical path and reduce considerably the volume of the optical system when applied to the waveguide system.