3D holographic near-eye display based on Fraunhofer diffraction using metalens as an eyepiece

The widespread use of holographic VR/AR devices are limited by bulky refractive and diffractive optics. To address these problems, a NED system combining the 3D CGH based on Fraunhofer diffraction and a metalens with 5 mm diameter as an eyepiece is proposed in this paper. Because of the capability of wavefront shaping in a subwavelength scale, the metalens eyepiece surly facilitates lightening the CGH-NED systems. Experiments are carried out for this design, where Fraunhofer diffraction with digital lens phases of different focal lengths are applied, and the metalens transforms the holographic reconstructed 3D image into virtual image to realize NED. The metalens eyepiece composed of silicon nitride anisotropic nanofins is fabricated with the diffraction efficiency and field of view for 532 nm incidence of 15.7% and 31°, respectively. Our work combining of CGH and metalens may provide a promising solution in future for computer-generated holographic 3D portable display.