Viewing angle enlargement in holographic augmented reality using an off-axis holographic lens

In this paper, a viewing angle enlargement method of holographic display using an off-axis holographic lens is proposed, and verification experiment of viewing angle enlargement is developed by using a single spatial light modulator (SLM) and an off-axis holographic lens fabricated by the holographic recording. The experimental results indicate that the viewing angle of holographic reconstructed image is increased to 11.2°, which is about 3.8 times as wide as the original viewing angle formed by the single SLM only. Furthermore, a see-through holographic display system for augmented reality (AR) is constructed, where virtual image is generated by holographic projection. The real scene and the virtual image will fuse together by using the off-axis holographic lens as the image combiner. The results prove that the proposed system can reconstruct virtual three-dimensional (3D) image with correct depth cues, solve the accommodation-vergence conflict problem effectively, and achieve the holographic AR 3D display effect without visual fatigue.